GEOENGINEERING: PARTS I, II, AND III

HEARING

BEFORE THE

COMMITTEE ON SCIENCE AND 

TECHNOLOGY 

HOUSE OF REPRESENTATIVES

ONE HUNDRED ELEVENTH CONGRESS

FIRST SESSION 

AND 

SECOND SESSION

NOVEMBER 5, 2009

FEBRUARY 4, 2010

and 

MARCH 18, 2010

Serial No. 111–62

Serial No. 111–75

and 

Serial No. 111–88

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GEOENGINEERING: PARTS I, II, AND III

HEARING

BEFORE THE

COMMITTEE ON SCIENCE AND 

TECHNOLOGY 

HOUSE OF REPRESENTATIVES

ONE HUNDRED ELEVENTH CONGRESS

FIRST SESSION 

AND 

SECOND SESSION

NOVEMBER 5, 2009

FEBRUARY 4, 2010

and 

MARCH 18, 2010

Serial No. 111–62

Serial No. 111–75

and 

Serial No. 111–88

Printed for the use of the Committee on Science and Technology

(

Available via the World Wide Web: http://science.house.gov 
(II)

COMMITTEE ON SCIENCE AND TECHNOLOGY 

HON. BART GORDON, Tennessee, Chair 

JERRY F. COSTELLO, Illinois 

EDDIE BERNICE JOHNSON, Texas 

LYNN C. WOOLSEY, California 

DAVID WU, Oregon 

BRIAN BAIRD, Washington 

BRAD MILLER, North Carolina 

DANIEL LIPINSKI, Illinois 

GABRIELLE GIFFORDS, Arizona 

DONNA F. EDWARDS, Maryland 

MARCIA L. FUDGE, Ohio 

BEN R. LUJA ́ N, New Mexico 

PAUL D. TONKO, New York 

STEVEN R. ROTHMAN, New Jersey 

JIM MATHESON, Utah 

LINCOLN DAVIS, Tennessee 

BEN CHANDLER, Kentucky 

RUSS CARNAHAN, Missouri 

BARON P. HILL, Indiana 

HARRY E. MITCHELL, Arizona 

CHARLES A. WILSON, Ohio 

KATHLEEN DAHLKEMPER, Pennsylvania 

ALAN GRAYSON, Florida 

SUZANNE M. KOSMAS, Florida 

GARY C. PETERS, Michigan 

JOHN GARAMENDI, California 

VACANCY 

RALPH M. HALL, Texas 

F. JAMES SENSENBRENNER JR., 

Wisconsin 

LAMAR S. SMITH, Texas 

DANA ROHRABACHER, California 

ROSCOE G. BARTLETT, Maryland 

VERNON J. EHLERS, Michigan 

FRANK D. LUCAS, Oklahoma 

JUDY BIGGERT, Illinois 

W. TODD AKIN, Missouri 

RANDY NEUGEBAUER, Texas 

BOB INGLIS, South Carolina 

MICHAEL T. MCCAUL, Texas 

MARIO DIAZ-BALART, Florida 

BRIAN P. BILBRAY, California 

ADRIAN SMITH, Nebraska 

PAUL C. BROUN, Georgia 

PETE OLSON, Texas 

SUBCOMMITTEE ON ENERGY AND ENVIRONMENT

HON. BRIAN BAIRD, Washington, Chair 

JERRY F. COSTELLO, Illinois 

EDDIE BERNICE JOHNSON, Texas 

LYNN C. WOOLSEY, California 

DANIEL LIPINSKI, Illinois 

GABRIELLE GIFFORDS, Arizona 

BEN R. LUJA ́ N, New Mexico 

PAUL D. TONKO, New York 

JIM MATHESON, Utah 

LINCOLN DAVIS, Tennessee 

BEN CHANDLER, Kentucky 

JOHN GARAMENDI, California 

BART GORDON, Tennessee 

BOB INGLIS, South Carolina 

ROSCOE G. BARTLETT, Maryland 

VERNON J. EHLERS, Michigan 

JUDY BIGGERT, Illinois 

W. TODD AKIN, Missouri 

RANDY NEUGEBAUER, Texas 

MARIO DIAZ-BALART, Florida 

RALPH M. HALL, Texas 

CHRIS KING Democratic Staff Director 

SHIMERE WILLIAMS Democratic Professional Staff Member 

ADAM ROSENBERG Democratic Professional Staff Member 

JETTA WONG Democratic Professional Staff Member 

ANNE COOPER Democratic Professional Staff Member 

ROBERT WALTHER Democratic Professional Staff Member 

DAN BYERS Republican Professional Staff Member 

TARA ROTHSCHILD Republican Professional Staff Member 

JANE WISE Research Assistant 
(III)

C O N T E N T S

Geoengineering: Assessing the Implications of LargeScale Climate Intervention 

November 5, 2009

Page 

Witness List ............................................................................................................. 2

Hearing Charter ...................................................................................................... 3

Opening Statements

Statement by Representative Bart Gordon, Chairman, Committee on Science 

and Technology, U.S. House of Representatives ............................................... 11

Written Statement ............................................................................................ 12

Statement by Representative Ralph M. Hall, Ranking Minority Member, 

Committee on Science and Technology, U.S. House of Representatives ......... 13

Written Statement ............................................................................................ 13

Prepared Statement by Representative Jerry F. Costello, Member, Committee 

on Science and Technology, U.S. House of Representatives ............................. 14

Prepared Statement by Representative Eddie Bernice Johnson, Member, Committee on Science and Technology, U.S. House of Representatives ................. 14

Witnesses:

Dr. Ken Caldeira, Professor of Environmental Science, Department of Global 

Ecology, The Carnegie Institution of Washington, and Co-Author, Royal 

Society Report 

Oral Statement ................................................................................................. 16

Written Statement ............................................................................................ 17

Professor John Shepherd, FRS, Professional Research Fellow in Earth System 

Science, National Oceanography Centre, University of Southampton, and 

Chair, Royal Society Geoengineering Report Working Group 

Oral Statement ................................................................................................. 27

Written Statement ............................................................................................ 28

Biography .......................................................................................................... 32

Mr. Lee Lane, Co-Director, American Enterprise Institute (AEI) 

Geoengineering Project 

Oral Statement ................................................................................................. 33

Written Statement ............................................................................................ 34

Biography .......................................................................................................... 43

Dr. Alan Robock, Professor, Department of Environmental Sciences, School 

of Environmental And Biological Sciences, Rutgers University 

Oral Statement ................................................................................................. 43

Written Statement ............................................................................................ 45

Biography .......................................................................................................... 51

Dr. James Fleming, Professor and Director, Science, Technology and Society 

Program, Colby College 

Oral Statement ................................................................................................. 68

Written Statement ............................................................................................ 72

Biography .......................................................................................................... 79

Discussion 

The Eruption of Mt. Pinatubo: Natural Solar Radiation Management ........... 80

Structuring a Research Initiative ....................................................................... 80
Page

IV

The Potential Efficacy of Greenhouse Gas Mitigation ...................................... 82

Research and Development Before Application ................................................. 83

The Dire Need for Mitigation and Behavior Change ........................................ 84

The Need for a Multidisciplinary and Realistic Approach to Climate 

Change ............................................................................................................... 85

The Challenge of International Collaboration ................................................... 87

Agriculture and Livestock ................................................................................... 87

The Power of Scientific Innovation ..................................................................... 89

Geoengineering and Climate Simulations .......................................................... 90

A Potential Role for NASA .................................................................................. 90

Skepticism of Global Climate Change ................................................................ 95

Prioritizing Geoengineering Strategies .............................................................. 97

Needed International Agreements ...................................................................... 98

More on Livestock Methane Output ................................................................... 99

The Need for Mitigation ...................................................................................... 99

Global Dimming and Risks of Stratospheric Injections .................................... 100

The Impact of Ingenuity and Behavior Change ................................................ 100

Climate Modeling Resources ............................................................................... 101

Appendix 1: Answers to Post-Hearing Questions

Dr. Ken Caldeira, Professor of Environmental Science, Department of Global 

Ecology, The Carnegie Institution of Washington, and Co-Author, Royal 

Society Report ....................................................................................................... 109

Professor John Shepherd, FRS, Professional Research Fellow in Earth System 

Science, National Oceanography Centre, University of Southampton, and 

Chair, Royal Society Geoengineering Report Working Group .......................... 110

Mr. Lee Lane, Co-Director, American Enterprise Institute (AEI) 

Geoengineering Project ........................................................................................ 114

Dr. Alan Robock, Professor, Department of Environmental Sciences, School 

of Environmental And Biological Sciences, Rutgers University ....................... 118

Dr. James Fleming, Professor and Director, Science, Technology and Society 

Program, Colby College ....................................................................................... 126

Appendix 2: Additional Material for the Record

Letter to U.S. House of Representatives Committee on Science and Technology from ETC group, dated November 4, 2009 ............................................ 134

C O N T E N T S

Geoengineering II: The Scientific Basis and Engineering 

Challenges 

February 4, 2010

Witness List ............................................................................................................. 137

Hearing Charter ...................................................................................................... 138

Opening Statements

Statement by Representative Brian Baird, Chairman, Subcommittee on Energy and Environment, Committee on Science and Technology, U.S. House 

of Representatives ................................................................................................ 144

Written Statement ............................................................................................ 144

Statement by Representative Bob Inglis, Ranking Minority Member, Subcommittee on Energy and Environment, Committee on Science and Technology, U.S. House of Representatives ............................................................... 145

Written Statement ............................................................................................ 145
Page

V

Witnesses:

Dr. David Keith, Canada Research Chair in Energy and the Environment, 

Director, ISEEE Energy and Environmental Systems Group, University 

of Calgary 

Oral Statement ................................................................................................. 145

Written Statement ............................................................................................ 147

Biography .......................................................................................................... 151

Dr. Philip Rasch, Chief Scientist for Climate Science, Laboratory Fellow, 

Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory 

Oral Statement ................................................................................................. 151

Written Statement ............................................................................................ 153

Biography .......................................................................................................... 166

Dr. Klaus Lackner, Department Chair, Earth and Environmental Engineering, Ewing Worzel Professor of Geophysics, Columbia University 

Oral Statement ................................................................................................. 167

Written Statement ............................................................................................ 168

Biography .......................................................................................................... 175

Dr. Robert Jackson, Nicholas Chair of Global Environmental Change, Professor, Biology Department, Duke University 

Oral Statement ................................................................................................. 176

Written Statement ............................................................................................ 177

Biography .......................................................................................................... 182

Discussion 

Economic Costs of Geoengineering ..................................................................... 182

Atmospheric Sulfate Injections ........................................................................... 183

Land-Based Geoengineering ................................................................................ 184

Carbon Air Capture and Mineral Sequestration ............................................... 184

Public Opinion and Education ............................................................................ 185

Political, Scientific, and Economic Challenges .................................................. 185

Skepticism of Climate Change ............................................................................ 187

The Scientific Basis of Climate Change ............................................................. 195

Chemical & Geological Carbon Uptake .............................................................. 196

Alternatives to Fossil Fuels ................................................................................. 197

The Successes of Protera LLC and the Need for Innovation ............................ 197

Increasing Structural Albedo .............................................................................. 200

Alternative Fuels and Conservation Priorities .................................................. 200

Coal and Carbon Capture and Sequestration .................................................... 202

Economically Viable Energy Sources .................................................................. 203

Closing .................................................................................................................. 204

Appendix 1: Answers to Post-Hearing Questions 

Dr. David Keith, Canada Research Chair in Energy and the Environment, 

Director, ISEEE Energy and Environmental Systems Group, University 

of Calgary .............................................................................................................. 206

Dr. Philip Rasch, Chief Scientist for Climate Science, Laboratory Fellow, 

Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory .................................................................................................. 209

Dr. Klaus Lackner, Department Chair, Earth and Environmental Engineering, Ewing Worzel Professor of Geophysics, Columbia University .................. 214

Dr. Robert Jackson, Nicholas Chair of Global Environmental Change, Professor, Biology Department, Duke University ................................................... 215

Appendix 2: Additional Material for the Record 

Transcript of Discussion prior to the Formal Hearing Opening .......................... 218
Page

VI

C O N T E N T S

Geoengineering III: Domestic and International Research 

Governance 

March 18, 2010

Witness List ............................................................................................................. 220

Hearing Charter ...................................................................................................... 221

Opening Statements

Statement by Representative Bart Gordon, Chairman, Committee on Science 

and Technology, U.S. House of Representatives ............................................... 226

Written Statement ............................................................................................ 226

Statement by Representative Ralph M. Hall, Ranking Minority Member, 

Committee on Science and Technology, U.S. House of Representatives ......... 227

Written Statement ............................................................................................ 227

Prepared Statement by Representative Jerry F. Costello, Member, Committee 

on Science and Technology, U.S. House of Representatives ............................. 228

Panel I:

Hon. Phil Willis, MP, Chairman, Science and Technology Committee, United 

Kingdom House of Commons 

Oral Statement ................................................................................................. 229

Written Statement ............................................................................................ 232

Biography .......................................................................................................... 234

Discussion 

International Research Database ....................................................................... 246

The Future of Geoengineering Research in the U.K. ........................................ 247

Additional Opportunities for International Collaboration ................................ 248

Public Opinion of Geoengineering ...................................................................... 249

The U.K. Inquiry Process .................................................................................... 250

Panel II:

Dr. Frank Rusco, Director of Natural Resources and Environment, Government Accountability Office (GAO) 

Oral Statement ................................................................................................. 251

Written Statement ............................................................................................ 254

Biography .......................................................................................................... 271

Dr. Granger Morgan, Professor and Department Head, Department of Engineering and Public Policy, and Lord Chair Professor in Engineering, Carnegie Mellon University 

Oral Statement ................................................................................................. 272

Written Statement ............................................................................................ 274

Biography .......................................................................................................... 295

Dr. Jane Long, Deputy Principal Associate Director at Large and Fellow, 

Center for Global Strategic Research, Lawrence Livermore National Lab 

Oral Statement ................................................................................................. 296

Written Statement ............................................................................................ 297

Biography .......................................................................................................... 309

Dr. Scott Barrett, Lenfest Professor of Natural Resource Economics, School 

of International and Public Affairs and the Earth Institute at Columbia 

University 

Oral Statement ................................................................................................. 310

Written Statement ............................................................................................ 312

Biography .......................................................................................................... 320

Discussion 

Initial Regulations ............................................................................................... 320

A Potential Role for DOE and National Labs .................................................... 321
Page

VII

The Prospect of Unilateral Geoengineering ....................................................... 330

The National Security and Geopolitical Impacts of Climate Change .............. 332

The Role for Federal Agencies ............................................................................ 332

Appendix 1: Answers to Post-Hearing Questions 

Dr. Frank Rusco, Director of Natural Resources and Environment, Government Accountability Office (GAO) ...................................................................... 336

Dr. Scott Barrett, Lenfest Professor of Natural Resource Economics, School 

of International and Public Affairs and the Earth Institute at Columbia 

University ............................................................................................................. 341

Dr. Jane Long, Deputy Principal Associate Director at Large and Fellow, 

Center for Global Strategic Research, Lawrence Livermore National Lab ..... 345

Dr. Granger Morgan, Professor and Department Head, Department of Engineering and Public Policy, and Lord Chair Professor in Engineering, Carnegie Mellon University ...................................................................................... 351

Appendix 2: Additional Material for the Record 

CRS Report on the International Governance of Geoengineering ....................... 358

(1)

GEOENGINEERING: ASSESSING THE IMPLICATIONS OF LARGE-SCALE CLIMATE INTERVENTION 

THURSDAY, NOVEMBER 5, 2009

HOUSE OF REPRESENTATIVES, 

COMMITTEE ON SCIENCE AND TECHNOLOGY, 

Washington, DC.

The Committee met, pursuant to call, at 10:10 a.m., in Room 

2318 of the Rayburn House Office Building, Hon. Bart Gordon 

[Chairman of the Committee] presiding.
2
3

HEARING CHARTER

COMMITTEE ON SCIENCE AND TECHNOLOGY

U.S. HOUSE OF REPRESENTATIVES 

‘‘Geoengineering: Assessing the Implications of

Large-Scale Climate Intervention’’

THURSDAY, NOVEMBER 5, 2009

10:00 A.M.

2318 RAYBURN HOUSE OFFICE BUILDING

Purpose 

On Thursday, November 5, 2009, the House Committee on Science & Technology 

will hold a hearing entitled ‘‘Geoengineering: Assessing the Implications of 

Large-Scale Climate Intervention.’’ Geoengineering can be described as the deliberate large-scale modification of the earth’s climate systems for the purposes of 

counteracting climate change. Geoengineering is a controversial issue because of the 

high degree of uncertainty over potential environmental, economic and societal impacts, and the assertion that research and deployment of geoengineering diverts attention and resources from efforts to reduce greenhouse gas emissions. The purpose 

of this hearing is to provide an introduction to the concept of geoengineering, including the science and engineering underlying various proposals, potential environmental risks and benefits, associated domestic and international governance issues, 

research and development needs, and economic rationales both supporting and opposing the research and deployment of geoengineering activities. This hearing is the 

first in a series on the subject to be conducted by the Committee, with subsequent 

hearings intended to provide more detailed examination of these issues.

Witnesses

• Professor John Shepherd, FRS is a Professorial Research Fellow in Earth 

System Science at the University of Southampton, and Chair of the UK Royal 

Society working group that produced the report Geoengineering the Climate. 

Science, Governance and Uncertainty.

• Dr. Ken Caldeira is a professor of Environmental Science in the Department 

of Global Ecology and Director of the Caldeira Lab at the Carnegie Institution 

of Science at Stanford University, and a co-author of the Royal Society report.

• Mr. Lee Lane is a Resident Fellow and the Co-director of the Geoengineering 

Project at the American Enterprise Institute (AEI) and former Executive Director of the Climate Policy Center.

• Dr. Alan Robock is a Distinguished Professor of Climatology in the Department of Environmental Sciences at Rutgers University and Associate Director 

of Rutgers Center for Environmental Prediction.

• Dr. James Fleming is a Professor and Director of Science, Technology and 

Society at Colby College and the author of Fixing the Sky: The Checkered History of Weather and Climate Control.

Background

Climate 

Global warming is caused by a change in the ratio between the amount of incoming shortwave radiation from the sun and the outgoing longwave radiation. Greenhouse gases (GHG’s), such as carbon dioxide and methane, decrease the ability of 

longwave radiation to escape earth’s atmosphere. This makes it more difficult for 

radiation to ‘‘escape’’ and therefore, causes higher radiation absorption. The trapped 

energy causes higher global temperatures. Proposals for geoengineering typically include activities that alter the earth’s climate system by either directly reflecting 

solar radiation back into space or removing greenhouse gases from the atmosphere 

to stabilize the intake-output ratio. 

In pre-industrial times, the atmospheric concentration of carbon dioxide (CO2) remained stable at approximately 280 parts per million (ppm). Today the concentra-
4

1The Global Carbon Project’s CO2 emissions trends notes that CO2 emissions from fossil fuels 

and industrial processes have increased from 1.1% a year from 1990–1999 to 3.0% a year from 

2000–2004. This growth represents a faster rate of increase than projected by even the most 

fossil-intensive scenarios projected in by the IPCC in the late 1990s. Archived at http://

www.globalcarbonproject.org/global/pdf/TrendsInCO2Emissions.V15.pdf as of October 20, 

2009. 2Michael McCracken notes that the lowest concentration at which economic analyses [suggest] 

that stabilization seem even remotely possible is 450 ppm. See McCracken p. 2. 3 Hansen, James et al. Target Atmospheric C02: Where Should Humanity Aim? Open Atmospheric Science Journal., 2, 217–231, doi:10.2174/1874282300802010217. 4 Associated Press Interview with Seth Borenstein, April 8, 2009. See also his clarifying follow 

up email, published by Andrew C. Revkin, New York Times, April 9, 2009. 

tion stands at approximately 385 ppm and is steadily increasing. While some industrialized countries’ emissions have remained flat in recent years—due in part to 

slowing economic growth and reduction of economic energy-intensity—overall global 

emissions are still growing more rapidly than most 1990s climate projections had 

anticipated,1 currently increasing CO2 concentrations by approximately 2 ppm per 

year. 

Estimates on safe and plausible CO2 concentration targets vary greatly. Climate 

scientists at the National Oceanic and Atmospheric Administration (NOAA) and a 

consensus of other scientific authorities identify 350 ppm as the long-term upper 

limit of atmospheric carbon concentrations that avoid significant environmental consequences. A climate panel led by NASA’s Dr. Jim Hansen identified the ecological 

‘‘tipping point,’’ the level at which atmospheric carbon, without additional increases, 

would produce rapid climate changes outside of our control, to be 450 ppm.2 3 The 

U.S. Global Change Research Program has also identified a stabilization target of 

450 ppm in order to ‘‘keep the global temperature rise at or below . . . 2° F above 

the current average temperature, a level beyond which many concerns have been 

raised about dangerous human interference with the climate system.’’

Pending U.S. climate legislation and international initiatives under the United 

Nations Framework Convention on Climate Change (UNFCCC) would establish 

goals for reducing domestic and global greenhouse gas emissions and accelerating 

development of low-carbon or zero-carbon energy technologies. However, many in 

the international climate community hold that even the most aggressive achievable 

emissions reductions targets will not result in the avoidance of adverse impacts of 

climate change and ocean acidification. Given global economic growth trends, many 

consider reaching 450 ppm and temperature increases of more than 2° C to be imminent. The Intergovernmental Panel on Climate Change (IPCC) estimated in its 2007 

assessment report that, under various emissions scenarios, the global temperature 

average will rise between 1.1 and 6.4° C by the year 2100, resulting in sea level 

rise of 18 to 59 cm in the same time frame. 

Further complicating these projections is the possibility of non-linear, ‘‘runaway’’ 

environmental reactions to climate change. Two such reactions that would amount 

to climate emergencies are rapidly melting sea ice and sudden thawing of Arctic permafrost. Sea ice reflects sunlight, and as it melts it exposes more (darker) open 

ocean to sunlight, thus absorbing more heat and accelerating melting and sea level 

rise. Likewise, as Arctic permafrost thaws it releases methane, a more powerful 

greenhouse gas than CO2, which then further decreases the Earth’s albedo and accelerates warming.

Geoengineering 

It is for these reasons that geoengineering activities are considered by some climate experts and policymakers to be potential ‘‘emergency tool’’ in a much broader 

long-term and slower acting global program of climate change mitigation and adaptation strategies. Dr. John Holdren, director of the Office of Science and Technology 

Policy and President Obama’s lead science advisor, asserted that while 

geoengineering proposals are currently problematic due to potential environmental 

side effects and financial costs, the possibility ‘‘has got to be looked at’’ as an emergency approach.4 While the deployment of geoengineering will likely remain a very 

controversial subject, an increasing number of experts are calling for a robust and 

transparent international research and development program to help determine 

which, if any, geoengineering proposals have potential for slowing climate change, 

and which carry unacceptable environmental or financial risk. 

Scientific hypotheses resembling geoengineering were published as early as the 

mid 20th century, but serious consideration of the topic has only begun in the last 

few years. In 1992 the National Academies of Sciences published a brief review of 
5

5 National Academy of Sciences. ‘‘Chapter 28: Geoengineering.’’ In Policy Implications of 

Greenhouse Warming: Mitigation, Adaptation and the Science Base, 422–464. National Academies Press, 1992. 6 Council on Foreign Relations, workshop notes, May 2008. 

7For example, Rutgers University received a research grant in May 2008 to be led by Alan 

Robock and Richard P. Turco to perform collaborative research on the implications of stratospheric aerosols and sun shading. 8The Canadian Forest Service’s Forest Carbon Accounting Program educates land managers 

and the public on forestry’s contribution to GHG management and establishes a National Forest 

Carbon Monitoring Accounting and Reporting System (NFCMARS). Archived online at http://

carbon.cfs.nrcan.gc.ca/CBM-CFS3¥e.html as of October 20, 2009. Scientific sources on the impact of trees on atmospheric carbon generally attribute between 15 and 20% of global GHG 

emissions to deforestation.

climate engineering concepts 5 and provided rough cost estimates for injecting 

aerosols into the stratosphere to reflect sunlight.6 The Academies will also finalize 

a report in early 2010 which, in part, formally addresses geoengineering. The Intergovernmental Panel on Climate Change (IPCC) plans to do the same in its 5th report, to be finalized in 2014. The U.S. Department of Energy penned a White Paper 

in 2001 recommending a $64 million, five-year program for research as part of the 

National Climate Change Technology Initiative, but it was not published. NASA 

held a workshop in April 2007 to discuss solar radiation management options. In 

May 2008, the Council on Foreign Relations held the forum Geoengineering: Workshop on Unilateral Planetary Scale Geoengineering. Earlier in 2009, the Defense Advanced Research Projects Agency (DARPA) began consideration of funding certain 

geoengineering research initiatives, and NSF has funded independent research 

projects on potential implications.7 Last Friday, the Massachusetts Institute of 

Technology hosted a public symposium, ‘‘Engineering a Cooler Earth: Can We Do It? 

Should We Try?’’ In September of this year, the United Kingdom’s Royal Society—an equivalent to 

the U.S. National Academies—published what many consider to be the most significant report on geoengineering entitled Geoengineering the Climate: Science, Governance and Uncertainty, which outlines various geoengineering methods and the associated challenges in research, ethics and governance. Otherwise, in general, the 

body of work on geoengineering consists of a limited number of individual scientific 

papers exploring variations of a few potential strategies, and the body of evaluative 

information on specific topics remains modest and mostly theoretical. The specific 

ecological safety issues and ethical considerations, similarly, have been assessed by 

only a handful of scientists and ethicists. Cost estimations for the various strategies 

are generally rough. Some are inexpensive enough to be undertaken unilaterally by 

independent nations or even wealthy individuals, while others entail immensely expensive technologies that would likely only be carried out through international 

partnerships. 

The Royal Society report and other studies divide geoengineering methods into 

two main categories: Solar Radiation Management (SRM) methods that reflect 

a portion of the sun’s radiation back into space, reducing the amount of solar radiation trapped in the earth’s atmosphere; and Carbon Dioxide Removal (CDR)

methods that involve removing CO2 from the atmosphere. SRM and CDR present 

fundamentally different challenges of governance, ethics, economics, and ecological 

impacts and experts most often assess them as wholly separate topics.

Carbon Dioxide Removal (CDR) or Air Capture (AC) 

CDR purports to remove greenhouse gases from the atmosphere, either by displacement or by stimulating the pace of naturally occurring carbon-consuming 

chemical processes. CDR strategies have the advantage of lowering the carbon content of the atmosphere. However, several of the options would be slow to implement 

and may be impossible to reverse. Those strategies involving a release of chemicals 

could also have a significant effect on vulnerable oceanic and terrestrial ecosystems. 

In addition, the chemical strategies would require increased mining efforts and the 

transportation of needed materials, which would carry its own environmental implications. Some of the potential strategies include:

Afforestation/avoided deforestation—planting new trees on earlier deforested 

lands or otherwise promoting forest growth results in greater carbon absorption. In 

addition, old growth forests are efficient carbon consumers. Many believe a more 

comprehensive plan for avoiding old-forest destruction could be a useful contribution 

to greenhouse gas management.8

Biological sequestration—Because terrestrial vegetation removes atmospheric carbon, carbon sinks can sequester carbon as biomass or in soil. This biomass could 
6

9For example, FutureGen and the Clean Coal Power Initiatives (CCPI) at DOE support 

RD&D for carbon capture and sequestration. 10The Royal Society report suggests a reduction of 1.8% (RS 23). 11 Novim 8. This inherent reflectivity of the earth is often referred to as ‘‘planetary albedo.’’ 12 Albedo is usually presented as a number between 0 and 1, 0 representing a material in 

which all radiation is absorbed and 1 a material which reflects all radiation. 13 Roughly 6 to 30 miles above the earth’s surface. 14The naturally-occurring sulfur emissions from the 1991 eruption of a volcano in the Philippines, Mt. Pinatubo, are thought to have decreased the average global temperature by ∼0.5°

C for a 1–2 year period by increasing global albedo. Another example of such short term atmospheric cooling is often attributed to the eruption of El Chico ́n in March 1982.

be used for fuels or sequestered permanently as biochar or other organic materials. 

The Committee held a hearing entitled Biomass for Thermal Energy and Electricity: 

A Research and Development Portfolio for the Future on October 21, 2009 that addressed this among other topics.

Enhanced weathering techniques—Silicate materials react with CO2 to form carbonates, thereby reducing ambient CO2. Silicate rocks could be mined and dispersed 

over agricultural soils, or released and dissolved into ocean waters (discussed 

below).

Carbon capture and sequestration (CCS)—Already the subject of several U.S. and 

international research and development initiatives for electric power plant applications,9 in this case CCS describes the capture of ambient GHGs and storage in geologic reservoirs, such as natural cave systems and depleted oil wells. Some 

geoengineering papers refer to this strategy as Carbon Removal and Storage (CRS). 

Oceanic upwelling and downwelling—the natural ocean circulation processes are 

increased and accelerated in order to transfer atmospheric GHGs to the deep sea, 

a kind of carbon sequestration, using vertical pipes.

Chemical ocean fertilization—The addition of iron, silicates, phosphorus, nitrogen, 

calcium hydroxide and/or limestone could enhance specific natural chemical processes which consume carbon, such as carbon uptake by phytoplankton.

Solar Radiation Management (SRM) or Sunlight Management 

Solar Radiation strategies do not modify CO2 levels in the atmosphere. Instead, 

they reflect incoming radiation to reduce the atmosphere’s solar energy content and 

restore its natural energy balance. Proposed reductions of solar radiation absorption 

are usually 1–2% 10; around 30% is already reflected naturally by the earth’s surface 

and atmosphere.11 The methods are space, land, or ocean-based and involve either 

introducing new reflective objects within or outside of the atmosphere, or an increase in the reflectivity or albedo 12 of existing structures and landforms. SRM 

could reduce increases in temperature, but it may not address the non-temperature 

aspects of greenhouse-induced climate changes. SRM strategies would generally 

take effect more quickly than CDR strategies. However, once started, some would 

likely require constant maintenance and/or replenishment to avoid sudden and drastic increases in temperature. Some SRM proposals include: 

Stratospheric Sulfate Injections—A spray of sulfates into the second layer of 

earth’s atmosphere 13 could reflect incoming solar radiation to reduce absorption. 

This process occurs naturally after a volcanic eruption, in which large quantities of 

sulfur dioxide are released into the stratosphere.14

White roofs and surfaces—Painting the roofs of urban structures and pavements 

of urban environments white would increase their albedo by 0.15–0.25 (15–25%). 

This strategy was suggested by DOE Secretary Steven Chu in May of 2009 at the 

St. James Palace Nobel Laureate Symposium.

Cloud brightening/Tropospheric Cloud Seeding—A fine spray of salt water or sulfuric acid is injected into the lowest level of our atmosphere to encourage greater 

cloud formation over the oceans, which would increase the local albedo.

Land use changes—Portions of the earth’s natural land cover could be modified 

for more reflective growth patterns, such as light colored grasses. Also, existing agricultural crops could be genetically modified to reflect more sunlight.

Desert reflectors—Metallic or other reflective materials could be used to cover 

largely underused desert areas, which account for 2% of the earth’s surface.

Space-based reflective surfaces—One large satellite or an array of several small 

satellites with mirrors or sunshades could be placed in orbit to reflect a portion of 

sun radiation before it reaches the earth’s atmosphere. Reflectors could also be 

placed at the sun-earth Lagrange (L 1) point, where the gravitational pulls from 

each body act with equal force and therefore allow objects to ‘‘hover’’ in place.
7

15 Royal Society 19 16For example, stratospheric injections and ocean fertilization would require large chemical 

inputs of mined materials. 

Key Strategies for Levying Assessments of Geoengineering Methods 

Very little applied research to demonstrate the efficacy and outside consequences 

of geoengineering proposals has been conducted so far; study has largely been limited to computer simulations. According to the Royal Society, outside of the existing 

RD&D programs for carbon sequestration and forest management, the only proposals that have undergone sustained research by the scientific community are certain types of ocean fertilization.15 Such research will likely need to be conducted 

over many years. Thus, experts argue that broad, collaborative discussions of proposed geoengineering methods should happen in the near term so policymakers can 

be sufficiently informed of their options well in advance of potential emergency climate events. 

The primary costs for program deployment can be determined with some measure 

of accuracy, but a program’s secondary costs (ecological, political, etc) and economic 

benefits will be more difficult to measure. Strenuous modeling is required to identify 

potential ecological impacts on, among other considerations: precipitation patterns 

and the hydrological cycle, ozone concentrations, agricultural resources, acid rain, 

air quality, ambient temperatures, and species extinction. Other factors to be examined include human health impacts, the costs incurred on consumers and taxpayers, 

impacts on minerals markets and increased mining needs,16 job creation or dissolution, international opinion/consensus, data collection and monitoring needs, sources 

of technology and infrastructure, and the energy demands incurred by large scale 

deployment. Many of these criteria can be quantified in relatively absolute scientific 

and economic terms, but others will be difficult to measure and even more difficult 

to weigh against one another. 

Geoengineering methods with more encapsulated impacts (e.g. reforestation and 

white roofs) are expected to be easier to research and implement from a governance 

standpoint, but the evaluation of concentrated impacts on community natural resources and microeconomies remains a challenge. 

The reversibility of any geoengineering proposal is also a factor. Reversibility includes both the time it takes to end the program itself (e.g. the time it takes for 

stratospheric sulfate injections to dissipate) and the time in which the externalities 

will be ended and/or remediated (e.g. the time it takes for additional sulfates in the 

ecosystem to recede). Identifying the party responsible for reversing a 

geoengineering application, should it become necessary, is also a key front end consideration. 

Lastly, both the cost of carbon credits and public opinion are expected to heavily 

impact which strategies would be most viable. Just as a significant price on carbon 

would encourage the development of carbon-neutral energy sources, a higher price 

per ton of CO2, paired with offsets allowances, would likely increase the economic 

viability of many CDR options such as reforestation and CCS. Similarly, public preference for particular strategies will affect the viability of application for different 

methods. 

Experts in the field believe that the risks and costs associated with the various 

geoengineering strategies must not only be assessed in comparison to one another, 

but also relative to the potential costs of inaction on climate change or insufficient 

mitigation efforts.

Risks and Detriments

Unilateral deployment—It is possible for a non-governmental group or individual 

to undertake one of the higher-impact, lower-cost geoengineering initiatives unilaterally, perhaps without scientific support or any risk management strategy. As recognized in the Royal Society report, the materials for stratospheric injections, for example, would be readily available and affordable to a small group or even a wealthy 

individual. For this reason and others, national and global security are also key concerns with geoengineering and international governance may be needed at the front 

end.

Moral hazard—Another concern is that the public knowledge of widespread implementation of geoengineering represents a moral hazard, in which a person or group 

perceiving itself insulated from risk is more likely to engage in risky or detrimental 

behavior. The Royal Society suggests that there is significant risk in large-scale efforts being treated as a ‘‘get out of jail free card,’’ in which carbon sensitive consumer decision-making for mitigation will wane. Federal funding and political mo-
8

17 Royal Society 5

mentum for mitigation could also be compromised if geoengineering is seen as a superior substitute for traditional mitigation and adaptation.

Ocean Acidification—A clear and significant disadvantage of geoengineering is 

that, unlike carbon mitigation strategies, most strategies do not reduce the progress 

of ocean acidification or destruction of coral reefs and marine life due to higher 

ocean temperatures. CDR methods address ambient carbon levels and could indirectly affect ocean carbon levels by slowing the rate of carbon uptake, but it is not 

clear that decreases in atmospheric carbon would help reverse ocean acidification. 

SRM methods do not address carbon levels at all.

Accidental Cessation of SRM—One critical drawback of SRM methods specifically 

is that, because they do not modify atmospheric carbon concentrations, a disruption 

of service could result in large and rapid changes in climate, i.e. a return to the unmitigated impact of increased carbon levels. If SRM methods are undertaken without congruent controls on GHG emissions, then we would be constantly at risk of 

dramatic climate changes if the SRM program ends. These potential rapid, potentially catastrophic impacts must be carefully considered before implementation at 

any scale. A concurrent charge against geoengineering is that we may not have the 

political power, funds, foresight or organization, either domestically or internationally, for long-term governance of projects of this scale without incurring unacceptable negative impacts.

Food and Water Security—A large-scale initiative impacting weather patterns 

could greatly modify the precipitation patterns in particular geographic areas, jeopardizing local food and fresh water supplies for local populations. For example, a 

drought incurred by unforeseen impacts of artificial cloud formation could suppress 

crop growth. Poor and developing nations may be particularly susceptible to such 

impacts.

Butterfly Effect—Ultimately, there is near certainty that some consequences of 

geoengineering methods cannot be anticipated and will remain unseen until fullscale deployment. Skeptics have alleged the possibility of an ecological ‘‘butterfly effect,’’ in which the secondary effects of geoengineering are so wildly unforeseen that 

a large scale ecological crisis could occur. Some scientists argue that the possibility 

that such harmful side effects may be larger than the expected benefits should deter 

consideration of some or all geoengineering proposals.

Governance and International Issues 

Any effective, large-scale modification of the climate will necessarily have global 

consequences. While the technical aspects of essentially every geoengineering method will require a great deal of additional research and examination, the legal, governmental, socio-political and ethical issues may ultimately be greater challenges to 

deployment. There are several fundamental questions on geoengineering governance 

that would need to be addressed: Who decides what methods are used? What regulatory mechanisms are there, and who establishes them? Who pays for the research, 

implementation, and surveillance? Who decides our ultimate goals and the pace in 

which we take toward achieving them? While some international treaties or agreements may be applicable to certain geoengineering applications, there are currently 

no regulatory frameworks in place aimed at geoengineering specifically.17 Furthermore, several proposed geoengineering strategies may directly violate existing treaties. These frameworks may pose an additional challenge for geoengineering implementation, but they may also provide guidance on ways to address the complex 

issues of jurisdiction and responsibility at the international scale. 

One challenge to address is the likelihood of inequitable effects on particular localities. Large-scale efforts conducted in a particular place may produce greater net impact on that region. For example, stratospheric aerosols injections in the Midwest 

United States might result in decreased crop outputs in the region. In addition, a 

weather pattern, ecosystem balance or wildlife population modified as an effect of 

geoengineering could yield a disproportionate effect somewhere outside the source 

area. This could, for example, cause erratic precipitation patterns in a nonparticipatory nation. 

It is not clear whether one or more existing international frameworks such as the 

Intergovernmental Panel on Climate Change (IPCC) or the United Nations Framework Convention on Climate Change (UNFCCC) could be the appropriate managing 

entity of global geoengineering governance issues, or if the unique features of 

geoengineering would require the creation of a new international mechanism. In addition, as geoengineering is multidisciplinary, several domestic agencies at the Fed-
9

18Geoengineering’s Governance Vacuum: Unilateralism and the Future of the Planet. For the 

National Academies workshop Geoengineering Options to Respond to Climate Change: Steps to 

Establish a Research Agenda. Washington, DC. June 15–16, 2009. 19 Usually silver iodide or frozen CO2 20 A highly visible example of an application of weather modification occurred during the 2008 

Summer Olympic Games in China, when the Beijing Weather Engineering Office used cloud 

seeding to delay rainfall for several hours in order to accommodate the Games’ opening ceremonies. 21 NAS 3 22 Barrett 1 23 Barrett 2 24 Royal Society 43

eral level have clear jurisdiction over topics imbedded in all or some of the suggested geoengineering methods as well as their immediate research and development needs. A number of cabinet-level departments and Federal agencies may be 

directly pertinent to the concurrent agricultural, economic, international security, 

and governance issues.

Analogous Government Initiatives 

The early years of nuclear weapons testing display a number of similarities to 

geoengineering, including the difficulties of levying cost-benefit analyses of their impacts, uncertain ecological impacts, an unknown geographic scope of impact, and potential intra- and intergovernmental liability issues. This relationship is noted by 

the ETC Group for the U.S. National Academies workshop on geoengineering held 

earlier this year.18 Before the Limited Test Ban Treaty was signed in 1963, several 

nations regularly performed nuclear tests underwater and in the atmosphere without international agreement, regulation, or transparency. Of course, the consequences of nuclear radiation and the potential for creating weapons are inherently 

international, but domestic experimentation preceded diplomatic considerations. The 

global impacts on both human health and international diplomacy, incurred without 

international consent, were considerable. 

Human-engineered weather modification shares these characteristics as well. The 

most commonly used strategy is cloud-seeding, in which particles 19 are sprayed into 

the air to stimulate condensation and cloud formation. This practice is thought to 

modify precipitation patterns 20 in order to enhance crop growth, manage water resources and promote human safety from natural hazards like floods and droughts. 

In 2003, the National Academies’ National Research Council published its fourth report on weather modification, Critical Issues in Weather Modification Research. As 

of report publication there were 23 countries engaging in weather modification on 

a large scale, and China is the Nation most aggressively pursuing it, with an annual 

budget of over $40 million for hail suppression and precipitation enhancement. However, NAS concluded that ‘‘there is still no convincing scientific proof of the efficacy 

of intentional weather modification efforts. In some instances there are strong indications of induced changes, but this evidence has not been subjected to tests of significance and reproducibility.’’ 21 No consensus on the cause-and-effect relationship 

between cloud seeding and weather patterns has been determined, but it still continues to be practiced worldwide. 

Public Perception and Ethical Implications 

Due to the large uncertainties associated with most geoengineering methods, the 

opinions of the general public and the scientific community at this time generally 

vary from cautiously optimistic to unequivocally opposed. While a portion of the scientific community is committed to investigating the possibilities of geoengineering, 

another portion is resistant because geoengineering and carbon mitigation could be 

seen by some as direct substitutes22 and therefore in competition with one another, 

as discussed above. 

The general public may have qualms with geoengineering for several reasons. A 

given method’s efficacy and safety may not coincide with the general public’s perception, which then may unduly influence momentum toward an unjustified strategy. 

However, negative public perceptions of geoengineering may also prove to be a powerful catalyst for emissions reductions.23 A study by the British Market Research 

Bureau found that while participants were cautious or hostile toward 

geoengineering, ‘‘several agreed that they would actually be more motivated to undertake mitigation actions themselves’’ after a large-scale geoengineering application was suggested.24

One major ethical issue is that even in a best case scenario, some nations are expected to benefit more than others. Moreover, the effects won’t necessarily reflect 
10

which nations have contributed the most to the carbon problem (the debtors), nor 

those agent nations who devise, fund and execute the geoengineering activities. Another is the ‘‘Dr. Frankenstein’’ ethical concern, in which some believe deliberate 

human modification of the global climate is both a dangerous and inappropriate activity in the first place. 

Because geoengineering threatens to alter biological processes at a large scale, 

many are concerned that inequitable negative impacts may occur. Undue burdens 

may be placed on a particular locality, even if the locality or nation neither engaged 

in geoengineering nor produced a disproportionate share of anthropogenic carbon 

emissions. Because deployment and even applied research can hold global implications, open information access and an open equitable forum for international dialogue are expected to be requisite for a responsible approach to geoengineering.

Bibliography

Shepherd, John et al. Geoengineering the Climate: Science, Governance and Uncertainty. September, 2009. New York: The Royal Society, September, 2009.

Garstang, Michael et al. Critical Issues in Weather Modification Research. Washington, DC: The National Academies Press, 2003.

Barrett, Scott. ‘‘The Incredible Economics of Geoengineering.’’ Johns Hopkins University School of Advanced International Studies. 18 March, 2007.

Blackstock, J.J. et al. Climate Engineering Responses to Climate Emergencies. 

(Novim, 2009). Archived online at: http://arvix/org/pdf/0907.5140

Cicerone, Ralph J. ‘‘Geoengineering: Encouraging Research and Overseeing Implementation,’’ Climatic Change, 77, 221–226. 2006.

McCracken, Dr. Michael C. ‘‘Geoengineering: Getting a Start on a Possible Insurance Policy.’’ The Climate Institute. Washington, DC.

T.M.L. Wigley. ‘‘A Combined Mitigation/Geoengineering Approach to Climate 

Change.’’ Science Magazine, 314, 452. October 2006.
11

Chairman GORDON. Good morning. I would like to welcome everyone to today’s hearing of the House Committee on Science and 

Technology entitled Geoengineering: Assessing the Implications of 

Large-Scale Climate Intervention. 

I believe this hearing marks the first time that a Congressional 

committee has undertaken a serious review of proposals for climate 

engineering. That is not surprising because this is a very complex, 

controversial subject that has had little formal debate in the 

United States. 

Geoengineering carries with it a tremendous range of uncertainties, ethical and political concerns, and the potential for catastrophic environmental side-effects. But we are faced with the 

stark reality that the climate is changing, and the onset of impacts 

may outpace the world’s political and economic ability to avoid 

them. 

Therefore, we should accept the possibility that certain climate 

engineering proposals may merit consideration and, as a starting 

point, review research and development as appropriate. At its best 

geoengineering might only buy us some time. But if we want to 

know the answers we have to begin to ask the tough questions. 

Today we begin what I believe will be a long conversation. 

In fact, my intention is for this hearing to serve as the introduction to the concept of climate engineering. Over the next eight 

months the Committee will hold two to three more hearings to explore underlying science, engineering, ethical, economic and governance concerns in fuller detail. 

I am pleased to announce that this will be part of an inter-parliamentary project with our counterpart in the United Kingdom 

House of Commons Science and Technology Committee. When 

members of the Commons Committee visited us last spring, the 

Chairman, Phil Willis, proposed that we work together on issues of 

common interest. Geoengineering has decidedly global implications, 

and research should be considered in the context of a transparent 

international process. 

Yesterday the Commons Committee voted to undertake a parallel 

effort to examine the domestic and international regulatory framework that may be applicable to geoengineering. We will be in close 

contact with them, sharing the findings from our own efforts. When 

they complete their work in the spring, the Chairman of the Committee will testify before us in a hearing on domestic and international governance issues. 

But before we begin this discussion today I want to make something very clear upfront. My decision to hold this hearing should 

not in any way be misconstrued as an endorsement of any 

geoengineering activity, and the timing has nothing to do with the 

pending negotiations in Copenhagen. I know we will run the risk 

of misleading headlines. 

However, this subject requires very careful examination, and will 

likely only be considered as a potential stopgap tool in a much 

wider package of climate change mitigation and adaptation strategies. It will require years of internationally coordinated research 

for us to better understand our options, to examine the impacts, 

and to know if any activity warrants deployment. In the meantime 

nothing should stop us from pursuing aggressive long-term domes-
12

tic and global strategies for achieving deep reductions in greenhouse gas emissions. 

This issue is too important for us to keep our heads in the sand. 

We must get ahead of geoengineering before it gets ahead of us, or 

worse, before we find ourselves in a climate emergency with inadequate information as to the full range of options. As Chairman of 

the committee of jurisdiction, I feel a responsibility to begin a public dialogue and develop a record on geoengineering. 

With that, I look forward to a good, healthy discussion, and I 

turn it over to my distinguished Ranking Member, Mr. Hall, for his 

opening statement. 

[The prepared statement of Chairman Gordon follows:]

PREPARED STATEMENT OF CHAIRMAN BART GORDON

Good morning. I would like to welcome everyone to today’s hearing of the House 

Committee on Science and Technology entitled, ‘‘Geoengineering: Assessing the Implications of Large-Scale Climate Intervention.’’

I believe this hearing marks the first time that a Congressional Committee has 

undertaken a serious review of proposals for climate engineering. That is not surprising; it is a very complex and controversial subject that has seen little formal debate in the U.S. 

Geoengineering carries with it a tremendous range of uncertainties, ethical and 

political concerns, and the potential for catastrophic environmental side-effects. But 

we are faced with the stark reality that the climate is changing, and the onset of 

impacts may outpace the world’s political and economic ability to avoid them. 

Therefore, we should accept the possibility that certain climate engineering proposals may merit consideration and, as a starting point, review research and development as appropriate. At its best geoengineering might only buy us some time. But 

if we want to know the answers we have to first ask the tough questions. Today 

we begin what I believe will be a long conversation. 

In fact, my intention is for this hearing to serve as the introduction to the concept 

of climate engineering. Over the next 8 months the Committee will hold two to three 

more hearings to explore underlying science, engineering, ethical, economic and governance concerns in further detail. 

I am pleased to announce that this will be part of inter-parliamentary project 

with our counterparts in the United Kingdom House of Commons Science and Technology Committee. When members of the Commons Committee visited us last 

spring the Chairman, Phil Willis, proposed that we work together on issues of common interest. Geoengineering has decidedly global implications, and research should 

be considered in the context of a transparent international process. 

Yesterday the Commons committee voted to undertake a parallel effort to examine the domestic and international regulatory frameworks that may be applicable 

to geoengineering. We will be in close contact with them, sharing the findings from 

our own efforts. When they complete their work in the spring the Chairman of the 

Committee will testify before us in a hearing on domestic and international governance issues. 

Before we begin this discussion today I want to make something very clear upfront—my decision to hold this hearing should not in any way be misconstrued as 

an endorsement of any geoengineering activity, and the timing has nothing to do 

with the pending negotiations in Copenhagen. I know we run the risk of misleading 

headlines. 

However, this subject requires very careful examination, and will likely only be 

considered as a potential stopgap tool in a much wider package of climate change 

mitigation and adaptation strategies. It will require years of internationally-coordinated research for us to better understand our options, examine the impacts, and 

know if any activity warrants deployment. In the meantime nothing should stop us 

from pursuing aggressive long-term domestic and global strategies for achieving 

deep reductions in greenhouse gas emissions. 

This issue is too important for us to keep our heads in the sand. We must get 

ahead of geoengineering before it gets ahead of us, or worse, before we find ourselves in a climate emergency with inadequate information as to the full range of 

options. As Chairman of the committee of jurisdiction, I feel a responsibility to begin 

a public dialogue and develop a record on geoengineering. 
13

With that, I look forward to a healthy discussion, and I yield to the distinguished 

Ranking Member, Mr. Hall for his opening statement.

Mr. HALL. Mr. Chairman, I could make the shortest opening 

speech in the history of this committee. 

Chairman GORDON. Okay. 

Mr. HALL. I could say geoengineering, hello, but I won’t do that. 

I will just say to you that I thank you for holding this hearing 

today, and once again, the Commerce and this Committee in our 

duties are taking on issues that are really the forefront of cuttingedge science, and I appreciate your leadership. 

As many of my colleagues will agree, the debate about climate 

change is far from over, and I am sure that you have conducted 

and participated in that and came to the conclusion that the fact 

that there are still many, many opinions as to the causes, the effects and the potential solutions demonstrates how much uncertainty there is out there and how crucial it is for our Nation to continue to search for answers. 

Geoengineering, or climate engineering, is the intentional modification of the earth’s environment to promote—and just go to the 

definition and see that it is so broad that you could apply the term 

to almost any human changes that are made by humans and their 

surrounding environment, from building dams to deforestation. The 

actions are more local or regional in scope. The types of modifications we will be discussing are global in nature, and therefore, no 

matter what our preconceptions are, the implications of such technologies are far-reaching. 

I understand that the hearing is to be the first of a series of 

hearings on this topic, further exploring the scientific basis underpinning the concept of geoengineering, and the ethical concerns and 

issues surrounding any future development and deployment scenarios could be extremely helpful in advancing the discussion about 

geoengineering. 

I will reserve my full judgment on this issue until all the facts 

are in, but I have to admit I am a bit skeptical about this non-traditional approach. I know that our witnesses here today represent 

a variety of different viewpoints on geoengineering, and I am eager 

to listen to their thoughts about the issue. I am sure we will have 

plenty of questions to ask them. I really look forward to a very lively discussion, and I expect we are going to have one. 

So I think I have to thank you again, Mr. Chairman. This kind 

of opens up, you know—Alfred Hitchcock did The Birds. You remember that movie? And I have been working all since that time 

on a movie that have the elephants, flying elephants, you know, 

like Hitchcock had those birds that just were going to disturb the 

whole world. I don’t know if I can get that underway or not, but 

we will maybe work that in in some of this here. 

I would yield back to my Chairman, James Bond, and I thank 

you very much for letting me talk. 

[The prepared statement of Mr. Hall follows:]

PREPARED STATEMENT OF REPRESENTATIVE RALPH M. HALL

Thank you, Mr. Chairman. I would like to thank you for holding this hearing 

today on geoengineering. Once again, this Committee is tackling issues that are the 

forefront of cutting edge science, and I appreciate your leadership. 
14

As many of my colleagues will agree, the debate about climate change is far from 

over. I am sure that you concluded that the fact that there are still so many opinions as to the causes, the effects and the potential solutions, demonstrates how 

much uncertainty is out there and how crucial it is for our nation to continue to 

search for answers. 

Geoengineering, or climate engineering, is the intentional modification of the 

Earth’s environment to promote habitability. The definition is so broad that you 

could apply the term to any changes humans make in their surrounding environment, from building dams to deforestation. These actions are more local or regional 

in scope. The types of modifications we will be discussing this morning are global 

in nature, and therefore no matter what our preconceptions are, the implications of 

such technologies are far reaching. 

I understand that this hearing is to be the first of a series of hearings on the 

topic. Further exploring the scientific basis underpinning the concept of 

geoengineering, and the ethical concerns and issues surrounding any future development and deployment scenarios could be extremely helpful in advancing the discussion about geoengineering. I will reserve my full judgment on this issue until all 

the facts are in, but I have to admit I am a bit skeptical about this nontraditional 

approach. 

I know that our witnesses here today represent a variety of different viewpoints 

on geoengineering, and I am eager to listen to their thoughts about the issue. I’m 

sure that we will have plenty of questions to ask them, and I look forward to a lively 

discussion. 

So I have to thank you once again for holding this hearing, and I look forward 

to hearing from our distinguished witnesses.

[The prepared statement of Mr. Costello follows:]

PREPARED STATEMENT OF REPRESENTATIVE JERRY F. COSTELLO

Good Morning. Thank you, Mr. Chairman, for holding today’s hearing to examine 

the future of geoengineering strategies for reducing greenhouse gas emissions and 

counteracting climate change. 

This committee has met several times to discuss the implications of climate 

change and the best mechanisms to counter its effects. Throughout these discussions, we have emphasized the importance of working with our international partners to ensure that the global problem of climate change is addressed through a 

global solution. 

I am pleased to welcome our colleagues from the United Kingdom with whom this 

committee has worked to explore the potential of geoengineering as a means of reducing greenhouse gas emissions. 

I have been a strong supporter of many geoengineering techniques currently in 

use today, in particular the use of carbon capture and storage technology for coal, 

to reduce the amount of carbon released into the atmosphere. These demonstrated 

technologies allow us to combat climate change and continue using abundant natural resources. However, I am concerned about the unintended consequences of 

some geoengineering proposals. These untested techniques could have irreversible 

effects that may permanently change the chemical, physical and biological make-up 

of our oceans and land. While I recognize that these proposals are still in their earliest stages, I believe it is important to address these concerns early in the research 

effort. 

I would like to hear from our witnesses how they will address these risks during 

the in-depth discussions on the potential of geoengineering. Further, as research 

and development projects move forward, how will these concerns be addressed and 

what protections will be put in place. 

I welcome our panel of witnesses, and I look forward to their testimony. Thank 

you again, Mr. Chairman.

[The prepared statement of Ms. Johnson follows:]

PREPARED STATEMENT OF REPRESENTATIVE EDDIE BERNICE JOHNSON

Good morning, Mr. Chairman. 

I would like to welcome today’s panel to our hearing, focused on research and 

work done in the field of geoengineering. 

Perhaps the greatest challenge the science community will face in the years ahead 

is being able to moderate climate change and global warming. 
15

While I believe that cutting emissions of greenhouse gases is a priority in climate 

mitigation, we must also prepare for the possibility that our environment will continue 

to degrade. 

There is no simple, solution, and while geoengineering may be possible, we still 

face many hurdles to its implementation and success. 

There are a range of methods that are currently being considered in the field of 

geoengineering and I look forward to hearing more about their potential today. 

We need global solutions to this global problem. We cannot proceed with any approach until we thoroughly examine the potential downside and all of the legal and 

ethical ramifications. 

There is a great deal of uncertainty in this field and as we proceed with future 

hearing look forward to examining all the consequences of implementing this type 

of science. 

Today’s hearing represents a commitment on behalf of this Committee and Congress to work in a global capacity to foster this type of research. 

The witnesses who will join us are true subject experts. It is my hope that they 

can provide committee members with good information that is based on science. 

It is my hope that we can move forward proactively to devise policies for a broad 

approach to the problem of global warming. 

Thank you for hosting today’s full committee hearing to learn more about 

geoengineering.

Chairman GORDON. Well, Professor Shepherd, welcome to America. If there are other Members who wish——

Mr. HALL. I knew that would get me in trouble. 

Chairman GORDON. If there are other Members who wish to submit additional opening statements, your statements will be added 

to the record at this point. 

And now it is my pleasure to introduce our witnesses. Professor 

John Shepherd is a Professional Research Fellow in Earth System 

Science at the University of Southampton and Chair of the Royal 

Society Geoengineering Working Group that produced the report 

Geoengineering The Climate: Science, Governance & Uncertainty.

And it is the University of Southampton not located in New York. 

Dr. Ken Caldeira is a Professor of Environmental Science in the 

Department of Global Ecology at the Carnegie Institute of Washington and co-author of the Royal Society Report. Mr. Lee Lane is 

the Co-Director of the American Enterprise Institute for Public Policy Research’s Geoengineering Project. Dr. Alan Robock is a Professor at the Department of Environmental Science at the School 

of Environmental and Biological Sciences at Rutgers University. 

Dr. Robock, Mr. Rothman wanted us to give you his best. He is ill 

today but wanted to be with you. And Dr. James Fleming is a Professor and Director of the Science, Technology and Society Program 

at Colby College and the author of Fixing the Sky: The Checkered 

History of Weather and Climate Control.

As our witnesses should know, we will have five minutes for your 

spoken testimony. Your written testimony will be included in the 

record for the hearing, and when you have completed your spoken 

testimony we will begin the questions. Each Member then will have 

five minutes to question the witnesses. 

So we begin in the order, Dr. Caldeira. 

Dr. CALDEIRA. Isn’t Dr. Shepherd first? 

Chairman GORDON. Well, I am reading from my report here, and 

so you are first in that regard but if you would like to yield to Dr. 

Shepherd, then we will do that. So if you will turn on your mic, 

we will all be better off. 
16

STATEMENT OF DR. KEN CALDEIRA, PROFESSOR OF ENVIRONMENTAL SCIENCE, DEPARTMENT OF GLOBAL ECOLOGY, THE 

CARNEGIE INSTITUTION OF WASHINGTON, AND CO-AUTHOR, 

ROYAL SOCIETY REPORT 

Dr. CALDEIRA. Chairman Gordon, Ranking Member Hall, Members of the Committee, I thank you for giving me the opportunity 

today to speak with you about why it makes sense for us as American taxpayers to invest some of our hard-earned dollars in exploring ways to cost-effectively reduce the environmental threats that 

are facing us. 

I am a climate scientist working at the Carnegie Institution Department of Global Ecology. I have been studying climate and 

ocean acidification for over 20 years and investigating 

geoengineering options for more than 10 years. 

Climate change poses a real risk to Americans. The surest way 

to reduce this risk is to reduce emissions of greenhouse gases, such 

as carbon dioxide. We can build a 21st-century energy system 

based on solar and nuclear power along with carbon capture and 

storage from coal-, oil- and gas-fired power plants. I believe we can 

and will make this transformation to the clean energy system of 

the future. However, even if we decide to start building our 21stcentury energy system today, because of the long time lags involved, we will still face threats from climate change. 

The options we are discussing today can be divided into two categories with very different characteristics, solar radiation management [SRM] approaches and carbon dioxide removal [CDR] approaches. 

Solar radiation management methods, which you could also call 

sunlight reflection methods, seek to reduce the amount of climate 

change by reflecting some of the sun’s warming rays back to space. 

We know this basically works because volcanoes have cooled the 

earth in this way. Preliminary research suggests that we could rapidly and relatively cheaply put tiny particles high in the stratosphere and that this would cause the earth to cool quickly. 

Nobody thinks these approaches will perfectly offset the effects 

of carbon dioxide. For example, these methods do not address the 

problem of ocean acidification. However, preliminary climate model 

simulations indicate that these approaches could offset most climate change in most places most of the time. 

While these approaches may be able to reduce overall risk, they 

could and likely will introduce new environmental and political 

risks. 

In contrast, carbon dioxide removal approaches seek to reduce 

the amount of climate change and ocean acidification by removing 

carbon dioxide from the atmosphere. Essentially, these options reverse carbon dioxide emissions in the atmosphere by pulling carbon 

dioxide back out of the atmosphere. 

There are two basic types of carbon dioxide removal methods. 

One is to use growing forests or other plants to store carbon in organic forms. The other is to use chemical techniques. We could 

build centralized carbon dioxide removal factories or perhaps 

spread out finely ground-up minerals that would remove carbon dioxide from the atmosphere. 
17

With the exception of proposals to fertilize the oceans, carbon dioxide removal methods are unlikely to introduce new, unprecedented risks, so cost is likely to be the primary consideration governing deployment. 

Let me mention in closing that I do not think the term 

‘‘geoengineering’’ is very useful in informed discussions. The term 

has been used by so many people to refer to so many different and 

poorly defined grab bags of distantly related things that I do not 

believe the term can help us to think clearly about the decisions 

we need to make. 

So to conclude, we need multi-agency research programs in both 

sunlight reflection methods and carbon dioxide removal approaches 

to find cost-effective ways to protect American taxpayers from unnecessary environmental risk. Because these two basic approaches, 

the solar radiation management approaches and the carbon dioxide 

removal approaches, differ in so many dimensions, it seems unwise 

to link these research programs closely together. 

Solving our climate change problem is largely about cost-effective 

risk management. There are many different ways that risk might 

be diminished, and the most important of these is to reduce greenhouse gas emissions. However, we also need to improve our resilience so that we can better adapt to the climate change that does 

occur. We also need to understand whether there are ways that we 

can cost-effectively remove carbon dioxide and perhaps other greenhouse gases from the atmosphere. Lastly, we should try to understand whether thoughtful, intentional interventions into the climate system might be able to undo some of the damage that we 

are doing with our current, inadvertent intervention. 

The problem is too serious to allow prejudice to take options off 

of the table. I thank you for your attention, and I would be happy 

to answer your questions. 

[The prepared statement of Dr. Caldeira follows:]

PREPARED STATEMENT OF KEN CALDEIRA

1. Summary

Climate change poses a real risk to Americans. The surest way to reduce this risk 

is to reduce emissions of greenhouse gases. 

However, other options may also be available which could in some circumstances 

cost-effectively contribute to risk reduction. These options can be divided into two 

categories with very different characteristics:

• Solar Radiation Management (SRM) approaches seek to reduce the amount 

of climate change by reflecting some of the sun’s warming rays back to space.

Æ The most promising Solar Radiation Management proposals appear to be 

inexpensive (at least with respect to direct costs), can be deployed rapidly, and can cause the Earth to cool quickly. They attempt symptomatic 

relief without addressing the root causes of our climate problem. Thus, 

these methods do not address the problem of ocean acidification. While 

these approaches may be able to reduce overall risk, there is the potential that they could introduce additional environmental and political risk. 

Solar Radiation Management approaches have not yet been given careful 

consideration in international negotiations to diminish risks of climate 

change. The primary consideration governing whether such systems 

would be deployed is our level of confidence that they would really contribute to overall risk reduction.

• Carbon Dioxide Removal (CDR) approaches seek to reduce the amount of climate change and ocean acidification by removing the greenhouse gas carbon 

dioxide from the atmosphere.
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Æ The most promising of the Carbon Dioxide Removal approaches appear 

to be expensive (relative to SRM methods, but perhaps competitive with 

methods to reduce emissions), slow acting, and take a long time before 

they could cool the Earth. However, they address the root cause of the 

problem—excess CO2 in the atmosphere. There is no expectation that 

these methods will introduce any new unprecedented risks. Some Carbon 

Dioxide Removal approaches associated with forests and agricultural 

practices have received attention in international negotiations and in carbon offsetting schemes. The primary consideration governing whether 

Carbon Dioxide Removal approaches would be deployed is cost relative to 

options to reduce greenhouse gas emissions. 

We need multi-agency research programs in both Solar Radiation Management 

and Carbon Dioxide Removal. (Every agency that has something to contribute 

should be given a seat at the table.) Because Solar Radiation Management and Carbon Dioxide Removal approaches differ in so many dimensions, it seems unwise to 

link them closely together. In particular, Carbon Dioxide Removal approaches have 

more in common with efforts to reduce CO2 emissions than they have with Solar 

Radiation Management approaches.

• Solar Radiation Management research might best be led by agencies that 

have a strong track record in the highest quality science, with no vested interest in the outcome of such research, such as the National Science Foundation or perhaps NASA.

• Carbon Dioxide Removal research that focuses on storing carbon in reduced 

(organic) forms might best be led by agencies that are already involved in conventional Carbon Dioxide Removal methods involving agricultural or forestry 

practices. Carbon Dioxide Removal approaches which employ centralized 

chemical engineering methods to remove CO2 from the atmosphere might best 

be led by agencies, such as DOE, already involved in carbon dioxide capture 

from power plants. It is less clear where research into distributed chemical 

approaches might fit best, although leadership by the National Science Foundation is a possibility.

2. Background

Climate change represents a real risk to Americans

It is increasingly obvious that modern industrial society is affecting climate. It is 

less clear how much this climate change will affect the average American. Nevertheless, it is reasonable to think that there is a significant risk that climate change 

will be more disruptive to our economy than a few million mortgage defaults. 

Economists estimate that it might take 2% of our GDP to squeeze carbon dioxide 

emissions out of our energy and transportation systems. I believe that the risk is 

high that, if we continue to produce devices that dump carbon dioxide waste into 

the atmosphere, climate change will lead to problems that dwarf the subprime mortgage debacle. The recent subprime mortgage crisis, driven by defaults on several 

million mortgages, led to an approximately 4% reduction in worldwide GDP growth. 

Therefore, I believe a rational investor would invest 2% of our GDP to avoid this 

risk. 

When I am speaking, I often ask:

If we already had energy and transportation systems that met our needs without 

using the atmosphere as a waste dump for our carbon dioxide pollution, and I 

told you that you could be 2% richer, but all you had to do was acidify the 

oceans and risk killing off coral reefs and other marine ecosystems, all you had 

to do was heat the planet, and risk melting the ice caps with rapid sea-level rise, 

risk shifting weather patterns so that food growing regions might not be able to 

produce adequate amounts of food, and so on, would you take all of that environmental risk, just to be 2% richer?

Nobody I have ever spoken with has said that all of this environmental risk is 

worth being 2 % richer. (Some years, I have gotten a 2% raise and barely noticed 

it.) So, I think we have to agree that the main issue with solving the climate-carbon 

problem is not the cost per se—it is that the cost is high enough to make it difficult 

to generate the necessary level of cooperation needed to solve the problem. 

I do not know how much climate change will affect the average American. While 

I cannot with confidence predict great damage, I can predict great risk. 

The carbon-climate problem is about risk management—and the best, surest, and 

clearest way to reduce environmental risk associated with greenhouse gas emissions 

is to reduce greenhouse gas emissions. 
19

If you take the risk of climate damage seriously, you want to take action to diminish risk by reducing greenhouse gas emissions, but you would not want to limit 

yourself to only one risk-reduction approach. 

There may be novel approaches that could also help us manage risk associated 

with greenhouse gas emissions. However, these novel approaches are poorly understood and have been inadequately evaluated. There has been a paucity of the kind 

of research and development that would let us understand the positive and negative 

properties of these approaches. These novel approaches are not alternatives to reducing greenhouse gas emissions; they are supplementary measures that might help 

us reduce the risk of climate-related damage. Some of them are approaches that 

America might need in a time of crisis.

3. Introduction to the concept of ‘‘geoengineering’’

‘‘Geoengineering’’ is a catch-all term, used to refer to a broad collection of strategies to diminish the amount of climate change resulting from greenhouse gas emissions. The term ‘‘geoengineering’’ is used in different ways by different authors and 

there is no generally agreed-upon definition, although features common to strategies 

referred to by the word ‘‘geoengineering’’ generally include:

(1) Intent to affect climate

(2) Affecting climate at a regional to global scale

(3) Novelty or lack of familiarity

Emitting CO2 by driving a car is not generally considered geoengineering because, 

while it affects global climate, there is no intent to alter climate. Planting a shade 

tree to provide a cooler local environment is not generally considered geoengineering 

because, while there is intent to alter climate, it is not at a sufficiently large scale. 

Promoting the growth of forests as a climate mitigation strategy involves an intent 

to affect climate at global scales; however, we are familiar with forest management, 

so this approach does not have the novelty that would cause most people to use the 

word ‘‘geoengineering’’ to refer to it. 

The term ‘‘geoengineering’’ also has another meaning related to the engineering 

of tunnels and other structures involving the solid Earth. Furthermore, the term 

‘‘geoengineering’’ has been applied to large scale efforts to alter geophysical systems, 

such as the old Soviet plan to reroute northward flowing rivers so that they would 

instead flow south towards central Asia. 

Because ‘‘geoengineering’’ has been used by different people to refer to many different types of activities, and there is no single universally agreed definition, it is 

my opinion that the term ‘‘geoengineering’’ no longer has much use in informed discussions. More than that, use of the term ‘‘geoengineering’’ can have a negative influence on the ability to conduct an informed discussion, since there is little that 

can be said generally about such an ill-defined and heterogeneous set of proposals.

4. An introduction to the major ‘‘geoengineering’’ strategies

‘‘Geoengineering’’ strategies can be divided into two broad categories:

(1) Solar Radiation Management (SRM) and related strategies that seek to directly intervene in the climate system, without directly affecting atmospheric 

greenhouse gas concentrations.

(2) Carbon Dioxide Removal (CDR) and related strategies that seek to diminish 

atmospheric greenhouse gas concentrations, after the gases have already been 

released to the atmosphere.

These two broad classes of strategy are so different, that they should be treated 

as being independent of each other. Solar Radiation Management approaches 

(SRM—can also be thought of as Sunlight Reflection Methods) attempt to limit damage from elevated greenhouse gas concentrations—these methods are designed to 

provide symptomatic relief. In contrast, Carbon Dioxide Removal strategies try to 

remove the atmospheric drivers of climate change—these methods are designed to 

address the root causes of our climate problem. 

Solar Radiation Management proposals will inherently involve actions by governments, because the primary issues driving deployment of such approaches will involve questions of environmental risk reduction, equity, governance, and so on. (Of 

course, a clear scientific and technical basis needs to be developed to act as a foundation for these policy discussions.) 

In contrast, Carbon Dioxide Removal proposals would likely be driven by actions 

of private corporations, because the primary factor driving deployment is likely to 

be a price on carbon emissions. If it is more cost-effective to remove carbon dioxide 
20

from the atmosphere than to prevent an emission to the atmosphere, and local environmental issues have been adequately addressed, then there will be an economic 

driver to remove carbon dioxide from the atmosphere. 

Because the issues around Solar Radiation Management (and related approaches) 

differ so greatly from issues around Carbon Dioxide Removal (and related approaches), it is best to address these two classes of possible activities separately.

4.1 Solar Radiation Management (SRM) and related strategies

4.1.1. Overview of Solar Radiation Management

While proposals to intentionally alter climate go back a half century or more, relatively little research has been done on these strategies. Therefore, everything said 

about these approaches must be regarded as provisional and preliminary. The recent report on Geoengineering by the U.K. Royal Society provides a good summary 

of this preliminary research. 

The sun warms the Earth. Greenhouse gases make it harder for heat to leave the 

Earth. With additional greenhouse gases warming the Earth, one way to cool things 

back down is to prevent the Earth from absorbing so much sunlight. 

There are two classes of proposal that appear to be able to address a significant 

part, if not all, of globally averaged mean warming: (1) placing small particles high 

in the atmosphere to reflect sunlight to space or (2) seeding clouds over the ocean 

to whiten them so that they reflect more sunlight to space. 

The leading proposal for reflecting large amounts of sunlight back to space is the 

emplacement of many small particles in the stratosphere. We have good reason to 

believe that such an approach will fundamentally work because volcanoes have performed natural experiments for us. It is thought that the rate of particle injection 

needed to offset a doubling of atmospheric CO2 content is small enough that it could 

be carried in a single fire hose. The determination of whether we would ever want 

to deploy such a system would not depend on cost of the deployment, but rather 

on an assessment of whether it was really able to contribute to overall risk reduction, taking both environmental and political factors into consideration. 

In 1991, the Mt. Pinatubo volcano erupted in the Philippines, introducing a large 

amount of tiny particles into the stratosphere. This caused the Earth to cool by 

around 1 degree Fahrenheit. Within a year or two, most of this material left the 

stratosphere. Had we replenished this material, the total amount of cooling would 

have been more than enough to offset the average amount of warming from a doubling of atmospheric CO2 concentration. 

There are questions about how good a short term eruption is as an analogue for 

a continuous injection of material into the stratosphere. Nevertheless, the natural 

experiment of volcanic eruptions give us confidence that the approach will basically 

work, and while there might be negative consequences, the world will not come instantly to an end, and that after stopping a short-term deployment, the world is 

likely to return to its previous trajectory within years. 

Nobody should think that any Solar Radiation Management strategy will work 

perfectly. Sunlight and greenhouse gases act differently on the atmosphere. Sunlight 

strikes the surface of the Earth where it can both warm the surface and help to 

evaporate water. Greenhouse gases for the most part absorb radiation in the middle 

of the atmosphere. So, changes in sunlight can never exactly compensate for 

changes in greenhouse gases. 

However, preliminary simulations indicate that it should be possible to offset most 

of the climate change in most of the world most of the time. Climate model simulations show that deflecting some sunlight away from the Earth can make a high CO2

world more similar to a low CO2 world at most times and at most places. However, 

the climate might deteriorate in some places. This raises important governance 

issues in that Solar Radiation Management approaches (or Solar Reflection Methods) have the potential to cause harm at some times in some places, even if they 

are able to reduce overall environmental damage and environmental risk.

4.1.2. Concerns relating to Solar Radiation Management

While there is some expectation that Solar Radiation Management approaches 

can diminish most of the climate change in most of the world most of the time, it 

is possible that there could be bad effects that would render this offsetting undesirable. These bad effects could be environmental, or they could be socio-political. 

With regard to environmental negatives, it is possible there could be adverse 

shifts in rainfall, or damage to the ozone layer, or unintended impacts on natural 

ecosystems. These unintended consequences should be a major focus of a Solar Radiation Management research program. Furthermore, we must bear in mind that 
21

Solar Radiation Management proposals do not solve problems associated with ocean 

acidification (but they do not significantly affect ocean acidification). 

With regard to socio-political negatives, some countries might actually prefer their 

warmer high CO2 climate or perhaps they might be (or believe they are) negatively 

impacted by a Solar Radiation Management scheme—or perhaps countries might 

differ in the amount or type of Solar Radiation Management to be deployed. These 

sorts of issues could cause political tension. 

It is also possible that the perceptions that there is a technical fix could lull people into complacency, and diminish pressure for emissions reductions. However, 

when the U.K. Royal Society conducted a preliminary focus group, they found that 

people were even more willing to put effort into emissions reduction after hearing 

the extreme measures scientists are considering to reduce climate risk. Just because 

we wear seatbelts, that does not mean we will drive more recklessly. Seat belts can 

remind us that driving is a dangerous activity.

4.1.3. Governance, regulation, and when to deploy

4.1.3.1. Gradual deployments

Often, in discussions of Solar Radiation Management, there is an assumption that 

we are speaking about large scale deployments and some system of global governance is necessary. While discussions of governance and regulation of both experiments and deployments are necessary, it is not clear at this time what form that 

governance or those regulations should take. 

For example, it is thought that sulfur emissions from power plants might today 

be reflecting about 1 W/m2 back to space that would have otherwise been absorbed 

by Earth. This could be causing the Earth to be about 1 degree Fahrenheit cooler 

than it would otherwise be. In other words, if we cleaned up all of the sulfur emitted 

by power plants worldwide, the Earth might heat up another degree. 

Because sulfur lasts a year or more in the stratosphere but generally less than 

a week in the lower atmosphere, if we were to emit just a few per cent of the sulfur 

now emitted in the lower atmosphere into the upper atmosphere instead, we would 

get the same average cooling effect with a more than 95% reduction in overall pollution. What if China were to say, ‘‘For each power plant that we fit with sulfur scrubbers, we will inject a few percent of that sulfur in the stratosphere—and we will 

get the same average cooling effect with a greater than 95% reduction in our sulfur 

emissions.’’? 

Today, ships at sea burn high sulfur oil. These ships can leave white contrails in 

their wake, reflecting sunlight to space. The International Maritime Organization 

has requested that these sulfur emissions be curtailed for reasons related to pollution and health—and the expected outcome is additional global warming. What if 

these ships were retrofitted with cloud seeding devices that would produce these 

same contrails, but without releasing any pollution? (It has suggested that a seawater spray would do the job.) 

It is not clear whether these things would be good things to do or bad things to 

do. It is not clear what kind of governance or regulatory structures should be built 

around such activities. One reason why we need a research program and discussions 

about governance and regulation is so that we can make informed decisions about 

such issues.

4.1.3.2. Emergency deployments

While such gradual deployments might be one path to implement Solar Radiation 

Management schemes, there is another possibility. 

In every emissions scenario considered by the Intergovernmental Panel on Climate Change, temperatures continue to increase throughout this century. Because 

of lags in the climate system and the long time scales involved in transforming our 

energy and transportation systems, the Earth is likely to continue warming 

throughout this century, despite our best efforts to reduce emissions. Our actions 

to diminish emissions can reduce the rate of warming and reduce the damage from 

warming, but it is probably already too late for us to see the Earth start to cool 

this century, unless we engage in solar radiation management (or related climate 

system interventions). 

What if we were to find out that parts of Greenland were sliding into the sea, 

and that sea-level might rise 10 feet by mid-century? (Such rapid sea level rises apparently happened in the geologic past, even without the kind of rapid shock we are 

now applying to our climate system.) What if rainfall patterns shifted in a way that 

caused massive famines? What if our agricultural heartland turned into a perpetual 
22

dustbowl? And what if research told us that an appropriate placement of tiny particles in the stratosphere could reverse all or some of these effects? 

That was a lot of ‘‘what if’s’’, but nevertheless there is potential that direct intervention in the climate system could someday save lives and reduce human suffering. 

Moreover, direct intervention in the climate system might someday save lives and 

reduce suffering of American citizens. I do not know what the probabilities of such 

outcomes are, but I believe that if we take the risks associated with climate change 

seriously, we must investigate our options carefully and without prejudice. 

We do not want our seat belts to be tested for the first time when we are in an 

automobile accident. If the seat belts are not going to work, it would be good to 

know that now. If there is something really wrong with thoughtfully intervening in 

the climate system, we should try to find that out now, so that if a crisis occurs, 

policy makers are not put in the decision of having to decide whether to let people 

die or try to save their lives by deploying, at full scale, an untested system. 

We need the research now to establish whether such approaches can do more good 

than harm. This research will take time. We cannot wait to ready such systems 

until an emergency is upon us.

4.1.3.3. Building governance and regulatory structures

We should proceed cautiously in developing governance and regulatory structures 

that could address Solar Radiation Management approaches both in the deployment 

phase and in the research phase. 

At this point we know very lithe. It is very easy to sound as if you are taking 

the moral high ground by saying, ‘‘It is wrong to intentionally intervene in the climate system, so it should be disallowed.’’ However, every simulation of a Solar Radiation Management method that used a ‘‘reasonable’’ amount of solar offsetting has 

found that there is potential to offset most of the climate change in most places 

most of the time. If we really believe that climate change has the potential to cause 

loss of life and suffering, and we believe that Solar Radiation Management approaches may have the potential to cost-effectively reduce that loss of life and suffering, it could be immoral not to research and develop these options. 

Information on Solar Radiation Management approaches is at this point highly 

preliminary and has not been widely disseminated. Pushing too early for formal 

agreements may lock political entities into hard positions that will be difficult to 

modify later. Therefore, what is needed now for governance is a period of discussion, 

careful consideration, and learning. 

With respect to experiments, no additional regulation is needed for small scale 

field experiments designed to improve process understanding where there is no expectation of any detectable lasting effects and no detectable trans-boundary effects. 

Discussions need to begin about how to develop norms that might govern larger 

experiments where there is potential for detectable climate effects or where significant trans-boundary issues must be addressed. 

Since these larger experiments and deployments could affect people in many countries, it is important that these discussions occur both internationally and domestically. Initially, it is probably best if these discussions proceed informally, perhaps 

with the facilitation of scientific unions or professional organizations. 

In short, we need to do the informal groundwork now, so that we can develop the 

shared understanding that is necessary for the development of good governance and 

regulatory structures.

4.1.4. Additional Solar Radiation Management strategies

While this discussion has focused on introducing small particles high in the atmosphere, a number of other approaches have been proposed that attempt to reduce 

the amount of climate change caused by increased greenhouse gas concentrations 

in the atmosphere. These include proposals to whiten clouds over the ocean, to mix 

heat deeper into the ocean, to whiten roofs and roads, to put giant satellites in 

space, and so on. 

For a number of reasons, I believe that placing small particles high in the atmosphere is the most promising category of Solar Radiation Management approaches. 

However, approaches to whiten clouds over the ocean or mix heat downward into 

the deep ocean, both appear feasible and may be able to be scaled up to offset a 

large fraction of century-scale warming. Of these two options, whitening marine 

clouds seems more benign, but neither of these approaches has been subject to sufficient scrutiny. 

Most other proposed Solar Radiation Management (and related) approaches, either cannot be scaled up sufficiently (e.g., proposals to whiten roofs and roads) to 

be a ‘‘game changer’’, or cannot be cost-effectively scaled up quickly enough (e.g., 
23

massive satellites placed between the Earth and Sun) to make a difference this century.

4.1.4. Institutional arrangements for research

Within the United States, agencies such as National Science Foundation or NASA 

might be in the best position to lead research into Solar Radiation Management, although DOE, NOAA, and other agencies also may have important roles to play. 

It is important that this research be internationalized and conducted in as open 

and transparent a way as possible. 

While laboratory and small scale process studies in the field need no additional 

regulation at this time, larger scale field studies will require some form of norms, 

governance, or regulation. Discussions need to take place, both domestically and 

internationally, to better understand how to strike the best balance between allowing the advancement of science and technology while safeguarding our environment.

4.2 Carbon Dioxide Removal (CDR) and related strategies

We emit greenhouse gases to the atmosphere, causing the Earth to warm. Is there 

potential to actively remove these gases from the atmosphere? 

The answer is, ‘yes, we are confident that there are ways to remove substantial 

amounts of carbon dioxide from the atmosphere.’ By addressing the root cause of 

the climate change problem (high greenhouse gas concentrations in the atmosphere), 

Carbon Dioxide Removal strategies diminish climate risk. They also reduce ocean 

acidification. Carbon dioxide removal methods do not introduce significant new governance or regulatory issues. 

I would suggest that within the domain of Carbon Dioxide Removal there are at 

least two, and possibly three or more, relatively independent research programs. 

Because Carbon Dioxide Removal approaches represent a miscellaneous collection 

of approaches, there is no one taxonomy that would uniquely classify all of these 

proposals. Nevertheless, Carbon Dioxide Removal approaches can be divided into 

two categories:

• Strategies that use biological approaches (i.e., photosynthesis) to remove carbon dioxide from the atmosphere and store carbon in a reduced (organic) 

form.

• Strategies that use chemical approaches to remove CO2 from the atmosphere.

Biological approaches may be subdivided in several different ways, but one way 

is to divide them into land-based and ocean-based approaches. Proposed land-based 

biological approaches include planting forests, changing agricultural practices to result in more carbon storage, and burying farm waste. All of these methods are limited by the low efficiency of photosynthesis, and thus require significant land area, 

although in some cases this land can be multi-use. Many of these approaches are 

already the subject of considerable study and are already being considered in discussions about how to limit climate change. Current research indicates that biologically-mediated carbon storage in the ocean is problematic in several dimensions, 

and is not likely to represent a significant contributor to solving our climate change 

problems. 

Chemical approaches may be divided into two categories: centralized approaches 

and distributed approaches. Centralized approaches seek to build industrial chemical processing facilities to remove carbon dioxide from the atmosphere and store it 

in a form that cannot interact with the atmosphere. The most promising avenue appears to be to store the carbon dioxide underground in compressed form, as with 

conventional carbon capture and storage. Distributed approaches seek to spread 

chemicals over large areas of the land or ocean, where they can react with carbon 

dioxide and cause the carbon dioxide to be removed from the atmosphere. 

There are additional hybrid approaches that do not fit easily into this taxonomy. 

For example, it has been suggested that plants could be grown and then burned in 

power stations to generate electricity, and then the CO2 could be captured from the 

power stations and stored underground. 

More thought needs to be put into finding institutional homes for these research 

elements. While all of these research efforts are likely to require multi-agency input, 

it is likely that research into biologically based methods might best be led by agencies that have strong track records in the biological sciences or experience with agriculture and forestry issues. Research into the centralized chemical approaches 

might best be led by DOE, but this is uncertain.
24

5. Closing comments

Solving our climate change problem is largely about cost-effective risk management. There are many different ways that risk might be diminished. The most important of these is to diminish greenhouse gas emissions. However, we also need to 

improve our resilience so that we can better adapt to the climate change that does 

occur. We also need to understand whether there are ways that we can cost-effectively remove carbon dioxide and perhaps other greenhouse gases from the atmosphere. Lastly, we should try to understand whether a thoughtful intentional intervention in the climate system might be able to undo some of the damage of a 

thoughtless unintentional intervention in the climate system. This problem is too serious to allow prejudice to take options off the table.
25
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27

Chairman GORDON. Thank you, Dr. Caldeira. And Professor 

Shepherd, you are recognized. 

STATEMENT OF PROFESSOR JOHN SHEPHERD, FRS, PROFESSIONAL RESEARCH FELLOW IN EARTH SYSTEM SCIENCE, 

NATIONAL OCEANOGRAPHY CENTRE, UNIVERSITY OF 

SOUTHAMPTON, AND CHAIR, ROYAL SOCIETY 

GEOENGINEERING REPORT WORKING GROUP 

Professor SHEPHERD. Good morning, Mr. Chairman, Ranking 

Member, members of the Committee, ladies and gentlemen, thank 

you very much for the invitation to come and testify to you this 

morning. It is a privilege to have that opportunity, and my testimony will be largely based on the Royal Society study that you 

mentioned, Mr. Chairman, which was undertaken over the past 

year and which I chaired. The report of this study was published 

in September, and it is available on the Royal Society’s website, 

and printed copies have been made available to the Committee. 

The aim of this study was really to try and produce an authoritative and wide-ranging review to reduce the confusion and misinformation which exists in some quarters about this rather controversial and novel issue in order to enable a well-informed debate 

on the subject, and so it is a great pleasure for me to be here at 

the beginning of such a debate, and I hope that our work will be 

useful. 

The Working Group was composed of 12 members, mainly scientists and engineers from the U.K., but also included a sociologist, 

a lawyer and an economist and one member from the U.S.A., Dr. 

Caldeira on my left, and one from Canada. And the members of the 

group were not proponents of geoengineering; they reflected a very 

wide range of opinions on the subject, and all recognize that the 

primary goal is to make the transition to the low-carbon economy 

that Dr. Caldeira has already mentioned which we shall need to do 

eventually irrespective of climate change simply because fossil fuels 

are a finite resource. 

So our terms of reference were to consider and as far as possible 

to evaluate proposed schemes for geoengineering, which we took to 

mean the deliberate, large-scale intervention in the earth’s climate 

system primarily in order to moderate the global warming. Our 

study was based primarily on a review of the literature but also by 

a call for submissions of evidence, of which we received some 75. 

Since time is short, I would like to move directly to summarize 

the key messages of our study and first among these is that 

geoengineering is not a magic bullet. None of the methods that 

have been proposed provide an easy or immediate solution to the 

problems of climate change. There is a great deal of uncertainty 

about various aspects of virtually all the schemes that are being 

discussed. So at present, this technology, in whatever form it takes, 

is not an alternative to emissions reductions which remain the 

safest and most predictable method of moderating climate change, 

and in our view cutting global emissions of greenhouse gases must 

remain our highest priority. 

However, we all recognize that this is proving to be difficult, and 

in the future, given adequate research, geoengineering may be use-
28

ful to support the efforts to mitigate climate change by conventional means. 

We concluded that geoengineering is very likely to be technically 

possible, but there are major uncertainties and risks with all methods concerning not only their effectiveness but also their costs, 

their unintended environmental impacts, and the social consequences and mechanisms needed to manage them. 

So in our view, this is not a technology which is ready for deployment in the immediate future. It is, however, a technology that 

may be useful at some point in the future if we find that we have 

need of it. But it will not be available unless we undertake the necessary research, not only on the technology but particularly also on 

the environmental and social impacts of such proposals. And to do 

that we need to have a widespread public debate and widespread 

public engagement and especially to develop an acceptable system 

of governance. Geoengineering by intention will affect everybody on 

the planet because it is an intentional moderation of the environment, and consequently everybody has an interest in the outcome. 

And we need to find a way to engage the opinions of a very diverse 

group of people on the planet in order that this can be done in an 

orderly and acceptable manner. 

Dr. Caldeira has reviewed the major differences between some of 

the methods, which I support entirely. And I would say finally, too 

little is known about the technologies at this stage to pick a winner. What we need is research on a small portfolio of promising 

techniques of both major types in order that our Plan B will be well 

prepared, should we ever need it. 

Mr. Chairman, thank you very much. 

[The prepared statement of Professor Shepherd follows:]

PREPARED STATEMENT OF JOHN SHEPHERD

Preamble

This testimony is based extensively on the results of the U.K. Royal Society study 

undertaken during 2008 and 2009, which I chaired, entitled ‘‘Geoengineering the 

Climate: Science, Governance & Uncertainty’’. The report of this study was 

published in September 2009. It is available at on-line at http://royalsociety.org/

document.asp?tip=0&id=8770, and printed copies of it have also been made available to the Committee. For the study we considered Geoengineering to be the deliberate largescale intervention in the Earth’s climate system, in order to moderate global warming. The study was based primarily on a review of the available 

literature (concentrating so far as possible on published papers which have been 

peer reviewed) but also supplemented by a call for submissions of evidence (of which 

∼75 were received).

Key Messages

• Geoengineering is not a magic bullet: none of the methods proposed provides 

an easy or immediate solution to the problems of climate change, and it is not 

an alternative to emissions reductions.

• Cutting global emissions of greenhouse gases must remain our highest 

priority. However, this is proving to be difficult, and geoengineering may in the 

future prove to be useful to support mitigation efforts.

• Geoengineering is very likely to be technically possible. However, there 

are major uncertainties and thus potential risks with all methods, concerning their effectiveness, costs, and social & environmental impacts.

• Much more research is needed before geoengineering methods could realistically be considered for deployment, especially on their possible environmental impacts (as well as on technological and economic aspects).
29

• Widespread public engagement and debate is also needed, especially to develop an acceptable system of governance & regulation (for both eventual deployment and for some research activities)

Other major issues

Geoengineering comprises a very wide range of methods which vary in many 

ways. This includes:

• Methods that remove greenhouse gases from atmosphere (e.g. engineered air capture). 

Æ These address the root cause of problem and would be generally preferred, but they only act slowly and are likely to be costly.

• Methods that reflect a little sunlight (e.g. small particles in the upper atmosphere)

Æ These act quickly, and are relatively cheap, but have to be maintained so they may not be sustainable in the long term (there is a 

major problem if you stop) and they do nothing for ocean acidification 

(the ‘‘other CO2 problem’’).

We do not yet have enough information, so it is too soon to pick winners, and 

if geoengineering is ever deployed we may need a combination of both types of method. We therefore need to commence serious research and development on several of the promising methods, as soon as possible.

1) Introduction

It is not yet clear whether, and if so when, it may become necessary to consider 

deployment of geoengineering to augment conventional efforts to moderate climate 

change by mitigation, and to adapt to its effects. However, global efforts to reduce 

emissions have not yet been sufficiently successful to provide confidence that the reductions needed to avoid dangerous climate change will be achieved. There is a serious risk that sufficient mitigation actions will not be introduced in time, despite the 

fact that the technologies required are both available and affordable. It is likely that 

global warming will exceed 2° C this century unless global CO2 emissions are cut 

by at least 50% by 2050, and by more thereafter. There is no credible emissions scenario under which global mean temperature would peak and then start to decline 

by 2100. Unless future efforts to reduce greenhouse gas emissions are much more 

successful then they have been so far, additional action such as geoengineering may 

be required should it become necessary to cool the Earth this century. 

Proposals for geoengineering for climate intervention are numerous and diverse, 

and for our study we deliberately adopted a broad scope in order to provide a wideranging review. There has been much discussion in the media and elsewhere about 

possible methods of geoengineering, and there is much misunderstanding about 

their feasibility and potential effectiveness and other impacts. The overall aim of 

study was therefore to reduce confusion & misinformation, and so to enable 

a well-informed debate among scientists & engineers, policy-makers and the 

wider public on this subject. 

The working group which undertook the study was composed of 12 members (listed below). These were mainly scientists & engineers, but also included a sociologist, 

a lawyer and an economist. The members were mainly from U.K. but included one 

member from the U.S.A. and one from Canada, and the study itself had an international remit. The WG members were not advocates of geoengineering, and held 

a wide range of opinions on the subject, ranging from cautious approval to serious 

scepticism. 

The terms of reference for the study were to consider, and so far as possible 

evaluate, proposed schemes for moderating climate change by means of 

geoengineering techniques, and specifically:

1) to consider what is known, and what is not known, about the expected 

effects, advantages and disadvantages of such schemes

2) to assess their feasibility, efficacy, likely environmental impacts, and 

any possible unintended consequences

3) to identify further research requirements, and any specific policy and 

legal implications.

The scope adopted included any methods intended to moderate climate change 

by deliberate large-scale intervention in the working of the Earth’s natural climate 

system, but excluded:
30

a) Low-carbon energy sources & methods for reducing emissions of greenhouse gases (because these are methods for conventional mitigation, not 

geoengineering)

b) carbon capture & storage (CCS) at the point of emission, and

c) conventional afforestation and avoided deforestation schemes (because 

these are also not geoengineering per se and have been extensively considered elsewhere)

2) General issues

The methods considered fall into two main classes, which differ greatly in 

many respects, including their modes of action, the timescales over which they are 

effective, their effects on temperature and on other aspects of climate, so that they 

are generally best considered separately. These classes are:

1) Carbon dioxide removal (CDR) techniques which address the root cause 

of climate change by removing greenhouse gases from the atmosphere;

2) Solar Radiation Management (SRM) techniques that attempt to offset 

the effects of increased greenhouse gas concentrations by reflecting a small 

percentage of the sun’s light and heat back into space.

Carbon Dioxide Removal methods reviewed in the study include:

• Land use management to protect or enhance land carbon sinks;

• The use of biomass for carbon sequestration as well as a carbon neutral energy source ;

• Acceleration of natural weathering processes to remove CO2 from the atmosphere;

• Direct engineered capture of CO2 from ambient air;

• The enhancement of oceanic uptake of CO2, for example by fertilisation of the 

oceans with naturally scarce nutrients, or by increasing upwelling processes.

Solar Radiation Management techniques would take only a few years to have 

an effect on climate once they had been deployed, and could be useful if a rapid response is needed, for example to avoid reaching a climate threshold. Methods considered in the study include:

• Increasing the surface reflectivity of the planet, by brightening human structures (e.g. by painting them white), planting of crops with a high reflectivity, 

or covering deserts with reflective material;

• Enhancement of marine cloud reflectivity;

• Mimicking the effects of volcanic eruptions by injecting sulphate aerosols into 

the lower stratosphere;

• Placing shields or deflectors hi space to reduce the amount of solar energy 

reaching the Earth.

The scale of the impact required is global, and its magnitude is large. To have 

a significant effect on man-made global warming by an SRM method one would need 

to achieve a negative radiative forcing of a few WIm2, and for an effective CDR 

method one would need to remove several billion tons of carbon per year from the 

atmosphere for many decades. We did not consider in any detail any methods which 

were not capable of achieving effects approaching this magnitude. 

There are many criteria by which geoengineering proposals need to be evaluated, and some of these are not easily quantified. We undertook a preliminary and 

semi-quantitative evaluation of the more promising methods according to our judgement of several technical criteria only, namely their effectiveness, affordability, safety and timeliness. The cost estimates available are extremely uncertain, and it 

would be premature to attempt detailed cost-benefit analysis at this time.

3) Technical Aspects: feasibility, cost, environmental impacts and side-effects

Our study concluded that geoengineering of the Earth’s climate is very likely to 

be technically possible. However, the technology to do so is barely formed, and there 

are major uncertainties regarding its effectiveness, costs, and environmental impacts. If these uncertainties can be reduced, geoengineering methods could in the 

future potentially be useful in future to augment continuing efforts to mitigate climate change by reducing emissions. Given these uncertainties, it would be appropriate to adopt a precautionary approach: to enable potential risks to be assessed 
31

and avoided requires more and better information. Potentially useful methods 

should therefore be the subject of more detailed research and analysis, especially on 

their possible environmental impacts (as well as on technological and economic aspects). 

In most respects Carbon Dioxide Removal methods would be preferable to Solar 

Radiation Management methods, because they effectively return the climate system 

to a state closer to its natural state, and so involve fewer uncertainties and risks. 

Of the Carbon Dioxide Removal methods assessed, none has yet been demonstrated 

to be effective at an affordable cost, with acceptable side effects. In addition, removal of CO2 from the atmosphere only works very slowly to reduce global temperatures (over many decades). If safe and low cost methods can be deployed at an appropriate scale they could make an important contribution to reducing CO2 concentrations and could provide a useful complement to conventional emissions reductions. It is possible that they could even allow future reductions of atmospheric CO2

concentrations (negative emissions) and so address the ocean acidification problem. 

Carbon Dioxide Removal methods that remove CO2 from the atmosphere without 

perturbing natural systems, and without large-scale land-use change requirements, 

such as CO2 capture from air and possibly also enhanced weathering are likely to 

have fewer side effects. Techniques that sequester carbon but have land-use implications (such as biochar and soil based enhanced weathering) may be useful contributors on a small-scale although the circumstances under which they are economically 

viable and socially and ecologically sustainable remain to be determined. The extent 

to which methods involving large-scale manipulation of Earth systems (such as 

ocean fertilisation), can sequester carbon affordably and reliably without unacceptable environmental side-effects, is not yet clear. 

Solar Radiation Management techniques are expected to be relatively cheap and 

would take only a few years to have an effect on the climate once deployed. However 

there are considerable uncertainties about their consequences and additional risks. 

It is possible that in time, assuming that these uncertainties and risks can be reduced, that Solar Radiation Management methods could be used to augment conventional mitigation. However, the large-scale adoption of Solar Radiation Management 

methods would create an artificial, approximate, and potentially delicate balance between increased gas concentrations and reduced solar radiation, which would have 

to be maintained, potentially for many centuries. It is doubtful that such a balance 

would really be sustainable for such long periods of time, particularly if emissions 

of greenhouse gases were allowed to continue or even increase. The implementation 

of any large-scale Solar Radiation Management method would introduce additional 

risks and so should only be undertaken for a limited period and in parallel with 

conventional mitigation and/or Carbon Dioxide Removal methods. 

Of the Solar Radiation Management techniques considered, stratospheric aerosol 

methods have the most potential because they should be capable of producing large 

and rapid global temperature reductions, because their effects would be more uniformly distributed than for most other methods, and they could be readily implemented. However, potentially there are significant side-effects and risks associated 

with these methods that would require detailed investigation before large-scale experiments are undertaken. Cloud brightening methods are likely to be less effective 

and would produce primarily localised temperature reductions, but they may prove 

to be readily implementable, and should be testable at small scale with fewer governance issues than other SRM methods. Space based SRM methods would provide 

a more uniform cooling effect than surface or cloud based methods, and if long-term 

geoengineering is required, may be a more cost-effective option than the other SRM 

methods although development of the necessary technology is likely to take decades.

4) The Human Dimension (Public Attitudes, Legal, Social & Ethical issues)

The acceptability of geoengineering will be determined as much by social, legal 

and political issues as by scientific and technical factors. There are serious and complex governance issues which need to be resolved if geoengineering is ever to become 

an acceptable method for moderating climate change. Some geoengineering methods 

could probably be implemented by just one nation acting independently, and some 

maybe even by corporations or individuals, but the consequences would affect all nations and all people, so their deployment should be subject to robust governance 

mechanisms. There are no existing international treaties or bodies whose remit covers all the potential methods, but most can probably be handled by the extension 

of existing treaties, rather than creating wholly new ones. The most appropriate 

way to create effective governance mechanisms needs to be determined, and a review of existing bodies, treaties and mechanisms should be initiated as a high priority. It would be highly undesirable for geoengineering methods which involve ac-
32

tivities or effects that extend beyond national boundaries (other than simply the removal of greenhouse gases from the atmosphere), to be deployed before appropriate 

governance mechanisms are in place.

Overall Conclusion

The safest and most predictable method of moderating climate change is 

to take early and effective action to reduce emissions of greenhouse gases. 

No geoengineering method can provide an easy or readily acceptable alternative solution to the problem of climate change.

Key recommendations:

• Parties to the UNFCCC should make increased efforts towards mitigating 

and adapting to climate change, and in particular to agreeing to global emissions reductions of at least 50% by 2050 and more thereafter. Nothing now 

known about geoengineering options gives any reason to diminish these 

efforts.

• Further research and development of geoengineering options should be 

undertaken to investigate whether low risk methods can be made available if 

it becomes necessary to reduce the rate of warming this century. This should include appropriate observations, the development and use of climate models, and carefully planned and executed experiments. We suggested an expenditure of around £10M per year for ten years as an appropriate initial level 

for a U.K. contribution to an international programme, to which we would hope 

that the U.S.A. would also contribute a substantially larger amount.

Members of the working group

Chair 

Professor John Shepherd, University of Southampton, U.K.

Members 

Professor Ken Caldeira, Carnegie Institution, U.S.A. 

Professor Peter Cox, University of Exeter, U.K., 

Professor Joanna Haigh, Imperial College, London, U.K. 

Professor David Keith, University of Calgary, Canada. 

Professor Brian Launder, University of Manchester, U.K. 

Professor Georgina Mace, Imperial College, London, U.K. 

Professor Gordon MacKerron, University of Sussex, U.K. 

Professor John Pyle, University of Cambridge, U.K. 

Professor Steve Rayner, University of Oxford, U.K.

BIOGRAPHY FOR JOHN SHEPHERD

Professor John Shepherd MA Ph.D. CMath FLMA FRS is a Professorial Research 

Fellow in Earth System Science in the School of Ocean and Earth Science, National 

Oceanography Centre, University of Southampton, U.K. He is a physicist by training, and has worked on the transport of pollutants in the atmospheric boundary 

layer, the dispersion of tracers in the deep ocean, the assessment & control of radioactive waste disposal in the sea, on the assessment and management of marine fish 

stocks, and most recently on Earth System Modelling and climate change. His current research interests include the natural variability of the climate system on long 

time-scales, and the development of intermediate complexity models of the Earth climate system for the interpretation of the palaeo-climate record. He graduated {first 

degree in 1967 and Ph.D. in 1971) from the University of Cambridge. From 1989–

94 he was Deputy Director of the MAFF Fisheries Laboratory at Lowestoft, and the 

principal scientific adviser to the U.K. government on fisheries management. From 

1994–99 he was the first Director of the Southampton Oceanography Centre. He has 

extensive experience of international scientific assessments and advice in the controversial areas of fisheries management, radioactive waste disposal, and climate 

change, and has recently taken a particular interest in the interaction between 

science and public policy. He is Deputy Director of the Tyndall Centre for Climate 

Change Research, and a Fellow of the Institute of Mathematics and its Applications. 

He was elected a Fellow of the Royal Society in 1999, participated in the Royal Soci-
33

ety study on Ocean Acidification published in 2005, and chaired that on 

Geoengineering the Climate published in 2009.

Chairman GORDON. Thank you, Professor Shepherd. And now, 

Mr. Lane, you are recognized. 

STATEMENT OF MR. LEE LANE, CO-DIRECTOR, AMERICAN 

ENTERPRISE INSTITUTE (AEI) GEOENGINEERING PROJECT 

Mr. LANE. Chairman Gordon, Ranking Member Hall, other Members of the Committee, thank you very much for the opportunity 

to appear here this morning. 

I am Lee Lane. I am a Resident Fellow and head of the AEI 

Geoengineering Project. The American Enterprise Institute is a 

non-profit, non-partisan organization that engages in research and 

education on issues of public policy. AEI does not take organizational stances on the issues that it studies, and the views that I 

am going to express here this morning are entirely my own. 

I want to begin by warmly commending the Committee for convening this hearing, and my statement fundamentally urges that 

you treat this session as a first step toward embarking upon a serious, sustained and systematic exploration by the U.S. Government 

of research and development into solar radiation management in 

particular, one of the two approaches to climate engineering discussed by Dr. Caldeira and Dr. Shepherd. 

Solar radiation management, or SRM, as the Committee has 

heard, envisions offsetting manmade global warming by slightly 

raising the amount of sunlight that the earth reflects back into 

space. In a recent study, a panel of five highly acclaimed economists, including three Nobel laureates, rated R&D for two solar radiation management concepts as the first- and third-most productive kinds of investment that can be made in dealing with climate 

change. Now, the panel that did those rankings was well aware of 

the large uncertainties that continue to surround solar radiation 

management, and they were also aware of the fact that, in the long 

run, at least solar radiation management cannot replace the need 

for greenhouse gas emissions reductions. But at the same time, the 

panel was clearly very much aware of the vast potential that solar 

radiation management has. 

One preliminary assessment is that SRM, if deployed, might well 

produce savings in terms of reduce damages from climate change, 

in terms of $200 to $700 billion a year. So we have potentially a 

good deal of upside with this technology. 

The cost of an R&D effort into solar radiation management is 

likely to be miniscule in comparison with these potential benefits. 

SRM research is needed in part because for many nations, steep reductions in greenhouse gas emissions cost more than the perceived 

value of the benefits of making those reductions. The record of the 

last 20 years of climate talks amply demonstrates that the prospects for steep emissions reductions on a global scale are poor, and 

they are likely to remain so for an extended period of time. Yet, 

without such emissions reductions, and perhaps even with them, 

some risk exists that quite harmful climate change might occur. An 

SRM system might greatly reduce the potential for harm. SRM, it 

is true, carries some hazards of its own. An R&D program, though, 

provides the best chance of gaining the information that might be 
34

needed, both to assess the prospects of SRM in a more knowledgeable way and also perhaps to find ways of minimizing those risks 

in the future. 

At this point, the top priority should be to gain added knowledge 

about SRM. Eventually, the United States may wish to address 

questions of international governance, but at this point, our first 

goal should be to learn more about solar radiation management as 

a tool. 

I guess the single most important caution that I would like to 

leave with the Committee is that the governance arrangements for 

any research program, including one on solar radiation management, can either serve to nurture R&D success or they can serve 

to stifle it. And I think it is awfully important as we go forward 

in considering how we want to manage research and development 

into SRM that we keep in mind the need to balance the risks and 

the benefits of how we structure our R&D efforts. 

Thank you very much. 

[The prepared statement of Mr. Lane follows:]

PREPARED STATEMENT OF LEE LANE

1 Introduction

1.1 Summary

Chairman Gordon, ranking member Hall, other members of the Committee, thank 

you for the opportunity to appear before you today. I am Lee Lane, a Resident Fellow at the American Enterprise Institute, where I am also co-director of AEI’s 

geoengineering project. AEI is a nonpartisan, non-profit organization conducting research and education on public policy issues. AEI does not adopt organizational positions on the issues that it studies, and the views that I express here are solely 

my own. 

The Committee is to be commended for its decision to address the issue of 

geoengineering as a possible response to climate change. Climate change is an extremely difficult issue. It poses multiple threats that are likely to evolve over time. 

Too often, climate policy discussions have been locked into an excessively narrow 

range of possible responses. 

My statement this morning urges that the committee treat this hearing as a first 

step in what should grow into a serious, sustained, and systematic effort by the U.S. 

government to conduct research and development (R&D) on solar radiation management (SRM). SRM, as the committee has heard, envisions offsetting man-made global warming by slightly raising the amount of sunlight that the Earth reflects back 

into space. 

In a recent study, a panel of five highly acclaimed economists, including three 

Nobel laureates, rated fifteen possible concepts for coping with climate change. The 

rankings were based on the panel’s assessments of the ratio of benefits to costs of 

each approach. Research on the two SRM technologies discussed below ranked first 

and third among these concepts. The expert panel was aware that many doubts continue to surround SRM, but its members were also clearly impressed with SRM’s 

vast potential as one tool among several for holding down the cost of climate change. 

Research into SRM is needed in part because, for many nations, a steep decline 

in greenhouse gas (GHG) emissions may well cost more than the perceived value 

of its benefits (Nordhaus, 2008; Tol, 2009; Posner and Sunstein, 2008). The record 

of the last twenty years of climate negotiations amply demonstrates that steep emission reductions are unlikely, and will probably remain so for a long time to come. 

Yet, without such controls, and even with them, some risk exists that quite harmful 

climate change might occur. 

A successful SRM system could greatly reduce the risk of these harmful effects. 

SRM, it is true, carries some risks of its own. An R&D program may, however, provide additional information with which to assess these risks and, perhaps, to devise 

means to limit them. The potential net benefits of SRM are very large indeed. One 

recent study found that the difference between the costs of deploying SRM and the 

savings it could reap amount to $200 billion to $700 billion (Bickel and Lane, 2009). 
35

The costs of an R&D effort appear to be minuscule compared with these possible 

gains.

1.2 Main SRM concepts

SRM aims to offset the warming caused by the build-up of man-made greenhouse 

gases in the atmosphere by reducing the amount of solar energy absorbed by the 

Earth. GHGs in the atmosphere absorb long-wave radiation (thermal infrared or 

heat) and then radiate it in all directions-including a fraction back to Earth’s surface, raising global temperature. SRM does not attack the higher GHG concentrations. Rather, it seeks to reflect into space a small part of the sun’s incoming shortwave radiation. In this way, temperatures are lowered even though GHG levels are 

elevated. At least some of the risks of global warming can thereby be counteracted 

(Lenton and Vaughan, 2009). 

Reflecting into space only one to two percent of the sunlight that strikes the Earth 

would cool the planet by an amount roughly equal to the warming that is likely 

from doubling the pre-industrial levels of greenhouse gases (Lepton and Vaughan, 

2009). Scattering this amount of sunlight appears to be possible. 

Several SRM concepts have been proposed. They differ importantly in the extent 

of their promise and in the range of their possible use. At least two such concepts 

appear to be promising at a global scale: marine cloud whitening and stratospheric 

aerosols.

1.2.1 Marine Cloud Whitening

One current proposal envisions producing an extremely fine mist of seawater 

droplets. These droplets would be lofted upwards and would form a moist sea salt 

aerosol. The particles within the aerosol would be less than one micron in diameter. 

These particles would provide sites for cloud droplets to form within the marine 

cloud layer. The up-lofted droplets would add to the effects of natural sea salt and 

other small particles, which are called, collectively, cloud condensation nuclei 

(Latham et al., 2008). The basic concept was succinctly described by one of its developers:

Wind-driven spray vessels will sail back and forth perpendicular to the local 

prevailing wind and release micronsized drops of seawater into the turbulent 

boundary layer beneath marine stratocumulus clouds. The combination of wind 

and vessel movements will treat a large area of sky. When residues left after 

drop evaporation reach cloud level they will provide many new cloud condensation nuclei giving more but smaller drops and so will increase the cloud albedo 

to reflect solar energy back out to space.’’ (Salter et al., 2008)

The long, white clouds that form in the trails of exhaust from ship engines illustrate this concept. Sulfates in the ships’ fuel provide extra condensation nuclei for 

clouds. Satellite images provide clear evidence that these emissions brighten the 

clouds along the ships’ wakes. 

Currently, the widely discussed option for implementing this approach envisions 

an innovative integration of several advanced technologies. The system calls for 

wind-powered, remotely controlled ships (Salter et al., 2008). However, other more 

conventional deployment systems may also be possible (Royal Society, 2009). 

Analyses using the general circulation model of the Hadley Center of the U.K. Meteorological Office suggest that the marine clouds of the type considered by this approach contribute to cooling. They show that augmenting this effect could, in theory, 

cool the planet enough to offset the warming caused by doubling atmospheric GHG 

levels. A relatively low percentage of the total marine cloud cover would have to be 

enhanced in order to achieve the desired result. A British effort is developing hardware with which to test the feasibility of this concept (Bower et al., 2006).

1.2.2 Stratospheric Aerosols

Tnserting aerosols into the stratosphere is another approach. The record of several volcanic eruptions offers a close and suggestive analogy. The global cooling from 

the large Pinatubo eruption (about .5 degrees Celsius) that occurred in 1991 was 

especially well-documented (Robock and Mao, 1995). Such eruptions loft particles 

into the atmosphere. There, the particles scatter back into space some of the sunlight that would otherwise have warmed the surface. As more sunlight is scattered, 

the planet cools. 

Injecting sub-micron-sized particles into the stratosphere might mimic the cooling 

effects of these natural experiments. Compared to volcanic ash, the particles would 

be much smaller in size. Particle size is important because small particles appear 
36

to be the most effective form for climate engineering (Lepton and Vaughan, 2009). 

Eventually, the particles would descend into the lower atmosphere. Once there, they 

would precipitate out. ‘‘The total mass of such particles would amount to the equivalent of a few percent of today’s sulfur emissions from power plants’’ (Lane et al.,

2007). If adverse effects appeared, most of these effects would be expected to dissipate once the particles were removed from the stratosphere. 

Sulfur dioxide (SO2), as a precursor of sulfate aerosols, is a widely discussed candidate for the material to be injected. Other candidates include hydrogen sulfide 

(H2S) and soot (Crutzen, 2006). A fairly broad range of materials might be used as 

stratospheric scatterers (Caldeira and Wood, 2008). It might also be possible to develop engineered particles. Such particles might improve on the reflective properties 

and residence times now envisioned (Teller et al., 2003). 

The volumes of material needed annually do not appear to be prohibitively large. 

One estimate is that, with appropriately sized particles, material with a combined 

volume of about 800,000 m3 would be sufficient. This volume roughly corresponds 

to that of a cube of material of only about 90 meters on a side (Lane et al., 2007). 

The use of engineered particles could, in comparison with the use of sulfate aerosols, 

potentially reduce the mass of the particles by orders of magnitude (Teller et al.,

2003). 

Several proposed delivery techniques may be feasible (NAS, 1992). The choice of 

the delivery system may depend on the intended purpose of the SRM program. In 

one concept, SRM could be deployed primarily to cool the Arctic. With an Arctic deployment, large cargo planes or aerial tankers would be an adequate delivery system (Caldeira and Wood, pers. comm., 2009). A global system would require particles to be injected at higher altitudes. Fighter aircraft, or planes resembling them, 

seem like plausible candidates. Another option entails combining fighter aircraft 

and aerial tankers, and some thought has been given to balloons (Robock et al.,

2009).

1.3 Air capture of CO2 (AC)

Air capture (AC) of carbon dioxide (CO2) is the second family of climate engineering concepts. AC focuses on removing CO2 from the atmosphere and securing it in 

land- or sea-based sinks.

‘‘Air capture may be viewed as a hybrid of two related mitigation technologies. 

Like carbon sequestration in ecosystems, air capture removes CO2 from the atmosphere, but it is based on large-scale industrial processes rather than on 

changes in land use, and it offers the possibility of near-permanent sequestration of carbon.’’ (Keith et al., 2005).

Like carbon capture and storage (CCS), air capture involves long-term storage of 

CO2, but air capture removes the CO2 directly from the atmosphere rather than 

from the exhaust streams of power plants and other stationary sources (Bickel and 

Lane, 2009). 

Were technological progress to greatly lower the costs of AC, this approach might 

offer a number of advantages. However, even with costs far below those that are 

now possible, large-scale AC appears to face huge cost penalties vis-a`-vis SRM. For 

instance, compare the cost of using AC to achieve the cooling possible with one W 

m-22 of SRM. The present value cost of achieving this goal (over a 200-year period) 

with AC is (very optimistically) $5.6 trillion. The direct cost of SRM might well be 

less than $0.5 trillion (Bickel and Lane, 2009). 

Proponents of AC may argue that even this low level of SRM might entail some 

costs from unwanted side effects. AC, they may also note, conveys some added benefits with regard to ocean acidification. These points are well-taken; yet it is far from 

clear that, when taken together, these benefits would be worth anything even remotely near $5 trillion. It seems safe to conclude that, compared with SRM, when 

economics is accounted for, AC should be a distinctly lower priority target for R&D. 

Thus, the rest of my remarks this morning will focus on SRM.

2 Deploying SRM might yield large net benefits

2.1 Initial estimates of benefits and direct costs

Expert opinion suggests that SRM is very likely to be a feasible and effective 

means of cooling the planet (Royal Society, 2009). Indeed, this concept may have 

more upside potential than does any other climate policy option. At the same time, 

SRM, like all other options, entails risks, and these will be discussed below. 

As noted earlier, recent study found that the benefits of SRM exceeded the costs 

of operating the system by an amount that would translate into $200 billion to $700 
37

billion per year (Bickel and Lane, 2009). Some of these benefits stem from lowering 

the economic harm expected from climate change. SRM, by lowering the risk of 

rapid climate change, would also allow a more gradual path toward GHG control—

lowering the total costs of controls. 

It is quite true that these benefit estimates are preliminary and subject to many 

limitations. They do not, for instance, account for the indirect costs implied by possible unwanted side effects of SRM. These indirect costs could be substantial, and 

the next section of my statement will discuss them. At the same time, the estimate 

excludes several factors that would be likely to increase the estimated benefits.

2.2 Abrupt climate change might increase the value of SRM

For example, some grounds exist for fearing that many of the current models understate the risks of extremely harmful climate change (Weitzman, 2008). Emission 

controls, even if they could be implemented effectively, i.e. globally, require more 

than a century before actually cooling the planet (IPCC, 2007). SRM, however, 

might stand a much better chance of preventing the worst should such a nightmare 

scenario begin to unfold. Once developed, either of the two techniques discussed 

above could be deployed very rapidly. The low costs of SRM mean that a few nations 

working together, or even a single advanced state, could act to halt warming, and 

it could do so quickly (Barrett, 2009). 

Merely developing the capacity to deploy SRM, therefore, is like providing society 

with a climate change parachute. And like a real parachute, having it may be valuable even if it is not actually deployed. In general, the more one credits the risk 

of rapid, highly destructive climate change, the greater is the potential value of 

SRM.

2.3 Suboptimal controls will raise the value of SRM

Less-than-optimal GHG emission controls, or no controls, would decrease global 

economic welfare, but these flawed policies would actually increase the positive contribution of SRM. This fact is important because actual GHG controls are certain 

to be far from the broad, uniform, price-based incentives that economic analysis 

calls for. In fact, few, if any, countries are likely to implement controls of this kind 

(Lane and Montgomery, 2009). 

Excess GHG emissions are an example of a fairly common kind of market failure, 

which can arise when property rights allow open access to a valuable resource. Instances include open access to grazing land, fishing grounds, or to oil and gas reservoirs. Open access can cause under-investment in maintaining the resource and 

too much consumption of it (Eggertsson, 2003). In the case of climate, the open access resource is the atmosphere’s capacity to absorb GHG discharges. 

In principle, collective action could solve the problem by limiting access. In practice, efforts to limit open access property rights often founder. For example, wild 

ocean fish stocks are being seriously depleted. Curbs on the over-pumping of oil and 

gas resources have sometimes worked, but often they have only done so after a 

great deal of economic waste had already occurred (Libecap, 2008). So far, GHG control has been another instance of this pattern of frequent failure. 

Further, GHG control has many of the features that make an effective global solution more difficult to attain. In such transactions, the more diverse are the interests 

of the parties, the poorer are the prospects for success (Libecap, 2008). Contrasting 

value judgments often cause conflict (Alston and Mueller, 2008). With GHG controls, 

the differing interests of richer and poorer nations have emerged as especially problematic (Bial et al., 2001). 

Thus, for China and India, economic development offers better protection from 

harmful climate change than do GHG limits. This choice makes sense. Industrialization can boost the ability to adapt to climate change— Of course, it can also relieve 

many other more acute problems. For these countries, slowing growth in the name 

of GHG control may simply be a bad investment (Schelling, 2002). To put the matter 

bluntly, for China and India, there seem to be good reasons for thinking that taking 

any but the lowest cost steps to control GHG emissions is just not worth the cost. 

As a result, China and India have largely limited their GHG control steps to those 

that in the U.S. context have been called ‘‘no regrets’’ measures. These are steps 

that would make sense absent concern about climate change. Such measures will 

have at best marginal impacts on the growth of emissions. Yet unless far steeper 

GHG cuts are implemented, widely cited goals for 2050 and 2100 are simply unattainable (Jacoby et al., 2008). 

The most logical inference from this situation is that those goals will not, in fact, 

be met. If they are not, climate change damages will exceed those projected to occur 

with an optimal control regime, as will the risks of abrupt, high-impact climate 
38

change. This prospect suggests that SRM is likely to be more valuable than the recent Bickel/Lane analysis indicates.

3 Important uncertainties remain

SRM could, then, offer important help in reducing some of the risks of climate 

change, but it poses some risks as well.

3.1 Concerns about possible indirect costs

Some of the risks that have been ascribed to SRM are somewhat poorly defined 

(Smith, 2009). Others, however, are clear enough, at least in concept. One such risk 

is the possible lessening of rainfall. The strength of the Indian or African monsoons 

is a particular worry. Other concerns also exist. For example, until chlorine concentrations return to levels present in the 1980s, sulfate aerosols added to the stratosphere may retard the ozone layer’s recovery (Tilmes et al., 2008). 

Concerns have also arisen over acid precipitation if SO2 were injected into the 

stratosphere. In addition, stratospheric aerosol injections would whiten skies, interfere with terrestrial astronomy, and reduce the efficiency of some kinds of solar 

power (Robock, 2008). Finally, some analysis suggests the possibility of ‘‘rebound 

warming’’ should SRM be deployed for a long time period and then halted abruptly 

(Goes et al., 2009).

3.2 Viewing indirect costs in a larger perspective

Several points about the above concerns warrant attention. 

None of the possible ill-effects of SRM has been monetized. Therefore, how they 

compare with SRM’s apparently large potential benefits is unclear. In fact, the scale 

of the effects of these unintended consequences is highly speculative. With regard 

to the Indian monsoon, for example, the underlying climate science is too uncertain 

to assess the scale of the changes with confidence (Zickfeld et al., 2005). Thus, Rasch 

et al. (2008), on which Robock is an author, observe:

‘‘Robock et al. (2008) have emphasised that the perturbations that remain in the 

monsoon regions after geoengineering are considerable and expressed concern 

that these perturbations would influence the lives of billions of people. This 

would certainly be true. However, it is important to keep in mind that: (i) the 

perturbations after geoengineering are smaller than those without 

geoengineering; (ii) the remaining perturbations are less than or equal to 0.5 

mm d-1 in an area where seasonal precipitation rates reach 6–15 mm d-1; (iii) 

the signals differ between the NCAR and Rutgers simulations in these regions; 

and (iv) monsoons are a notoriously difficult phenomenon to model [Annamalai 

et al., 2007] [emphasis in original].

Ozone depletion may be a problem, but it is likely to grow less severe with the 

passage of time. Acid deposition seems to be a considerably less serious problem, 

as a recent study concluded that ‘‘. . . the additional sulfate deposition that would 

result from geoengineering will not be sufficient to negatively impact most ecosystems, even under the assumption that all deposited sulfate will be in the form 

of sulfuric acid’’ (Kravitz et al., 2009). 

On rebound warming, the significance of the problem is, again, unclear. For the 

effect to be large, the SRM regime would have to remain in place for at least several 

decades. Also, during this period, adaptation and GHG control efforts would have 

to be held to low levels (Bickel and Lane, 2009). Ex ante, such a course of events 

may be possible, but it hardly seems inevitable or, perhaps, even likely. 

All of these concerns may warrant study. Nonetheless, to take a step back from 

the details, a few broader factors should also be kept in mind. Most importantly, 

it is worth noting that the relevant choice before us is not between a climate-engineered world and a world without climate change; rather, it is between the former 

and the world that would prevail without climate engineering. SRM may, indeed, do 

some harm. Society may, however, have to choose between accepting this harm on 

the one hand and running the risk of a planetary emergency on the other (Bickel 

and Lane 2009). 

Finally, in assessing SRM, it is important to keep in mind that all climate policy 

options entail side-effects. GHG controls, for instance, may imply greater reliance 

on biofuels or nuclear power. Border tax adjustments may unleash a global trade 

war (Barrett, 2007). In weighing the relative priority of SRM and GHG control, 

these factors are no less relevant than SRM’s impacts on rainfall or ozone. The key 

to climate policy is fording the mix of responses that minimizes total costs more 

than it is about either/or choices.
39

4 Approaches to limiting the risks of SRM

Since the risks of unintended consequences are the major barriers preventing the 

exploitation of this option, it is important to ford means of lowering those risks. A 

number of options might serve this purpose.

4.1 R&D as a risk reduction strategy

Currently, we lack much of the information that would be needed to weigh all of 

the potential risks of SRM against its possible benefits. Only an R&D program can 

buy this information, and the potential benefits of SRM appear to be very large compared to the costs of such an R&D effort. A vigorous, but careful, R&D program may 

offer the means of reducing the risks of SRM. It may identify faulty concepts and 

ford new means of avoiding risks. Progress in climate science can also increase the 

expected benefits of SRM (Goes et al., 2009). 

Such an R&D program would begin with modeling and paper studies, move to laboratory testing, and eventually, embark on field trials. The latter would start small 

and increase in scale by increments. As R&D progresses, spending would increase 

from tens of millions of dollars in early years to the low billions of dollars later. 

Total spending may fall in the range of $10–15 billion (Bickel and Lane, 2009). The 

work would stress defensive research i.e. research designed to identify and limit 

possible risks. A recent report has defined this type of research agenda for stratospheric aerosols (Blackstock et al., 2009). 

Research cannot entirely eliminate risk (Smith, 2009). Yet the risk of deploying 

a system under emergency conditions and without full testing are likely greatly to 

exceed those entailed by deploying a more fully tried and better understood system. 

Again, none of the options for dealing with climate change is free of risk.

4.2 Delayed deployment as a risk management strategy

The passing of time seems likely to diminish the risks of deploying SRM. One option, therefore, might be to delay deployment. This approach offers two advantages. 

First, delay is likely to make it easier for the nations wishing to deploy SRM to 

gain international acquiescence for their plans. Today, some nations may still benefit from additional warming. Such states might strenuously object to near-term efforts to halt warming. Russia, one of the nations that might adopt this view, is a 

great power. It could probably apply enough pressure to prevent any other nation 

from deploying SRM. However, as decades pass, climate change is increasingly likely to threaten even Russia with net costs. As this happens, Russian and other objections to SRM are also likely to fade. 

Second, the ozone depletion problem will also diminish with time. The stock of 

ozone-depleting chemicals in the atmosphere is shrinking. Before mid-century, levels 

will return to those that prevailed pre-1980. At that point, the impact of stratospheric aerosols on UV radiation also loses significance (Wigley, 2006). 

Delayed deployment, of course, would also lower the difference between SRM’s 

total benefits and its direct costs. Even so, large net benefits remain. This result 

obtains for both SRM concepts. Thus, if marine cloud whitening were deployed in 

2055, the estimated present discounted value of the benefits exceeds that of the direct costs by at least $3.9 trillion, and perhaps by as much as $9.5 trillion (in 2005 

dollars). If stratospheric aerosols were deployed in 2055, the gap between total benefits and total costs would range between $3.8 trillion and $9.3 trillion (Bickel and 

Lane, 2009).

5 Proposals for international governance require caution

For some people, creating an international governance regime is the preferred 

choice for controlling the risks of SRM. A number of proposals for establishing systems of international governance of SRM seem suddenly to have sprouted up. Many 

of them seem to be couched in somewhat alarming tones about future conflicts, and 

most seem to be accompanied by expressions of great urgency (Victor et al., 2009). 

In responding to them, caution is in order.

5.1 Proposals for regulation require balancing of risks

To start with, it is important to recognize that a regime of controls can and often 

does produce counter-productive results. An overly restrictive system can raise the 

costs of undertaking R&D. Higher costs may narrow the field of active researchers. 

Since competition spurs technological progress, a regulatory regime that adds to research costs may slow the pace of progress (Arrow, 1962; Cohen and Noll, 1991; 

NRC 1999; Sarewitz and Cohen, 2009). If so, lowering the risks of unintended harm 
40

from SRM might be purchased at the costs of higher risks from abrupt, high-impact 

climate change. This trade-off may be worthwhile, or it may not be, depending on 

how one rates the relative risks.

5.2 U.S. interests may differ from those of other states

A second caution pertains to nations’ different weights in world politics. A few nations command much more heft than do others. The U.S., China, and Russia are 

clearly in this category; others may be in the process of joining it. These states have 

a disproportionate ability either to carry an SRM regime into effect or to impede 

another state from doing so. If any of these states were to conclude that SRM was 

necessary to protect its vital interests, a system of international restraints would 

be most unlikely to constrain them. 

For the U.S., the question of whether to foster the development of an international body with the authority to regulate SRM entails accepting possible future 

constraints on its own freedom of action, as well as constraints on other states that 

might be acting in accord with U.S. preferences. In exchange, the U.S. would gain 

possible added support were it is seeking to halt or change SRM activity by another 

power. 

In considering this trade-off, it may be worth pondering that at least two other 

great powers, China and Russia, are autocracies. It is at least possible that these 

states are far less constrained by global public opinion than is the United States. 

In this case, in consenting to the creation of a global regime for governing SRM, 

the U.S. might be accepting a more binding limit on its own actions than that which 

it gains on the actions of the other great powers.

5.3 Who should consider SRM regulation?

SRM regulation is a matter of U.S. foreign policy. In this matter, U.S. interests 

may be congruent with those of some countries and clash with those of others. In 

addition to distinctions in wealth, power, and climate, states may differ in risk 

averseness. The strength of the contrasting U.S. and E.U. reactions to genetically 

modified organisms suggest that in at least some specific instances, such differences 

may be large. 

Technical and scientific expertise is certainly important to the issue of how (or 

whether) SRM should be subject to international control. Yet the more basic question lies in the definition of national interests. This question is not technical; it is 

political. And how it is answered may well affect any nation’s choices among international control regimes. For this reason, recommendations made by panels of scientists or lawyers may miss central aspects of the issues and yield misleading results. Such advice may still provide useful insights, but it should be handled with 

care.

6 SRM as part of a broader context

6.1 Multiple responses are needed to cope with climate change

Multiple tools are available for coping with climate change. Adaptation to change 

is likely to be the primary response for many decades. Weak and patchy greenhouse 

gas (GHG) controls are in place, but these measures fall far, far short of those that 

would be needed to actually halt climate change. And they are likely to continue 

to do so. Solar radiation management (SRM) offers great upside potential. 

Still, it remains in the concept stage and is surrounded by uncertainties. Eventually, even air capture of CO2 may become appealing, although its economic feasibility remains speculative. 

In any case, a mix of climate policies is better than placing too much stress on 

any one response. GHG emissions pose multiple threats, and multiple responses are 

likely needed to respond to them. Further, at some point all responses are likely 

to encounter diminishing marginal returns. Excessive reliance on any one policy option is likely to raise net costs.

6.2 New knowledge as a key to climate policy success

With the current state of science and technology, the costs of coping with climate 

change are likely to be high. New knowledge may, however, drastically lower those 

costs. As just discussed, R&D on SRM may allow a better assessment of this option 

as well as offer ways of limiting its risks and controlling its costs. Better climate 

science is likely to enable more cost-effective adaption to climate change. R&D on 

new energy sources or on capturing and storing CO2 might lower the cost and raise 

the political acceptability of GHG controls. Each of the six climate policy options se-
41

lected by the above-mentioned economists’ panel as being the most promising centered on the search for one or another form of new knowledge. Clearly, in the economists’ opinions, research is a powerful strategy for dealing with climate change. 

The quest for new knowledge may not, though, be easy. First, its results are inherently uncertain. Diversified risks and hedging are important. Second, research 

can take time. Electrification of the global economy, for example, has been going on 

for over a century and is still far from complete. Third, the right kind of rules and 

structures can make the difference between success and failure. This Committee is 

very well positioned to raise questions about the kinds of arrangements likely to 

maximize the chances of R&D success. I hope that this hearing may prove to be an 

important step forward in that inquiry.

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BIOGRAPHY FOR LEE LANE

Lee Lane is a Resident Fellow at the American Enterprise Institute for Public 

Policy Research. He is Co-Director of AEI’s Geoengineering Project. Lane recently 

co-authored ‘‘An Analysis of Climate Engineering as a Response to Climate Change,’’ 

a benefit/cost analysis published by the Copenhagen Consensus Center. He has also 

recently written ‘‘Institutions for Developing New Climate Solutions’’. This paper is 

soon to be published in a book by the Geneva, Switzerland-based World Federation 

of Scientists. In 2008, Lane co-authored ‘‘Political Institutions and Greenhouse Gas 

Controls.’’ Mr. Lane was the lead author of NASA’s April 2007 report on 

geoengineering. He is also the author of Strategic Options for Bush Administration 

Climate Policy (AEI Press, November 2006). Lane has testified before Congress, and 

has been a consultant to the U.S. Department of Energy, the U.S. Department of 

Transportation, the State Department, NASA, and Japan’s Ministry of Economics, 

Trade, and Industry, as well as with CRA International, an international economics 

and management consulting firm. Before joining AEI, Lane served for seven years 

as the Executive Director of the Climate Policy Center, a policy research organization in Washington DC.

Chairman GORDON. Thank you, Mr. Lane. I also thank you for 

being an early supporter of ARPA–E. We hope that some of the research that will come out of ARPA–E will mean that this potential 

review will be moot. 

Mr. LANE. I hope so, too. 

Chairman GORDON. Dr. Robock, we welcome your discussion. 

STATEMENT OF DR. ALAN ROBOCK, PROFESSOR, DEPARTMENT OF ENVIRONMENTAL SCIENCES, SCHOOL OF ENVIRONMENTAL AND BIOLOGICAL SCIENCES, RUTGERS UNIVERSITY 

Dr. ROBOCK. Mr. Chairman, Mr. Hall, Members of the Committee, thank you for inviting me. First I would like to agree with 

Ken Caldeira, that global warming is a serious problem and that 

mitigation, reduction of emissions, should be our primary response. 

We also need to do adaptation and learn to live with some of the 

climate change which is going to happen no matter what. 

Using geoengineering should only be in the event of a planetary 

emergency and only for a temporary period of time, and it is not 

a solution to global warming. 

Could I have the first slide? 

[The information follows:]
44

I am a climatologist. I have done climate research and effects of 

volcanic eruptions for 35 years. We did a climate model simulation 

of what would happen if we put in the equivalent of one Mount 

Pinatubo volcanic eruption every four years. The green line is the 

global warming temperatures that we have seen up until now. The 

black line is one Pinatubo every four years. The brown line is one 

Pinatubo every two years, assuming that you could do it. 

This brings up several questions. What temperature do we want 

the planet to be? Do we want it to stay constant? Do we want it 

to be at 1980 levels, do we want it at 1880 levels? And who decides? What if Russia and Canada want it a little bit warmer and 

India wants it a little bit cooler? 

If we stopped after 20 years, we would have rapid warming, as 

you can see. We did it for 20 years. And this rapid climate change 

would be much more dangerous than the gradual change we would 

get without doing anything. So this is a couple of the reasons why 

I am concerned about it, but we certainly need more research. 

Now, how do we get the aerosols—I am talking about the solar 

radiation management. How do we get the aerosols into the stratosphere? There is no way to do it today. Ideas of artillery or balloons 

or airplanes need a lot of research. Ken said it would be easy and 

cheap, but there is no demonstration of that. It might not be that 

expensive, but such equipment just doesn’t exist today. 
45

So I have made a list of seven reasons why it—benefits for stratospheric geoengineering and 17 reasons why it might be a bad idea. 

Now, volcanic eruptions produce drought in Africa and Asia. 

They produce ozone depletion, no more blue skies, less solar power, 

and each of these needs to be quantified so you policymakers can 

make a decision about whether or not to implement it. We don’t 

have quantification of any of these yet. 

I disagree with the economic analysis because they just ignored 

many of the risks and didn’t even count what the possible dangers 

might be. But I agree with everybody that we need a research program so that we can quantify each of these so policymakers can tell 

if—is there a Plan B in your pocket, or is it empty? We really need 

to know that, and we don’t know the answer to that yet. 

If we were going to test putting particles in the stratosphere, we 

don’t have a system to observe them. The United States used to 

have a series of satellites called SAGE which looked at particles in 

the stratosphere. It was very useful for monitoring volcanic eruptions. And they stopped working, and there is no plan to put them 

up there. So we need the system anyway to monitor the stratosphere for the next volcanic eruption and to monitor it if we ever 

do experimentation. 

If we wanted to do experimentation, it is not possible to do just 

a small-scale test, to put a little bit of particles in and see what 

would happen. We could do that, but we couldn’t measure their effects because there are a lot of weather variability, a lot of weather 

noise. And so we would really have to put a lot of material in for 

a substantial period of time to see whether we are having an effect. 

And that would essentially be doing geoengineering itself. You can’t 

do it on a small scale. 

You could fly a plane up there and dump some gas out and see 

what would happen at the nozzle. But to do a full-scale experiment, 

we couldn’t do it. For example, if there is already a cloud there and 

we want to put gases in and see if we get more particles, you can’t 

do that if there are not particles there already. We may just make 

the particles bigger. And so it is problematic whether we could actually ever do an experiment in the stratosphere without actually 

doing geoengineering. 

So I would like to urge you to support a research program into 

the climatic response with climate models, into the technology to 

see if it is possible to develop different systems so that you can 

make an informed decision in the future. 

Thanks. 

[The prepared statement of Dr. Robock follows:]

PREPARED STATEMENT OF ALAN ROBOCK

Introduction

In the October 28, 2009, letter from Chairman Gordon inviting me to testify at 

the House Committee on Science and Technology Hearing, ‘‘Geoengineering: Assessing the Implications of Large-Scale Climate Intervention,’’ I was asked to address 

a number of specific issues, which I do below. But first I would like to give a brief 

statement of the framework within which we consider the issue of geoengineering. 

I agree with the October 21, 2009, statement from the leaders of 17 U.S. scientific 

societies to the U.S. Senate (Supplementary Material 1), partially based on my own 

research, that, ‘‘Observations throughout the world make it clear that climate 

change is occurring, and rigorous scientific research demonstrates that the greenhouse gases emitted by human activities are the primary driver.’’ I also agree with 
46

their statement that ‘‘Moreover, there is strong evidence that ongoing climate 

change will have broad impacts on society, including the global economy and on the 

environment.’’ Therefore, it is incumbent on us to address the threat of climate 

change. 

I also agree with the recent policy statement of the American Meteorological Society on geoengineering (Supplementary Material 2). I was a member of the committee that wrote this statement. As the statement explains, ‘‘Three proactive strategies could reduce the risks of climate change: 1) mitigation: reducing emissions; 2) 

adaptation: moderating climate impacts by increasing our capacity to cope with 

them; and 3) geoengineering: deliberately manipulating physical, chemical, or biological aspects of the Earth system.’’

Before discussing geoengineering it is necessary to define it. As the American Meteorological Society statement says, ‘‘Geoengineering proposals fall into at least 

three broad categories: 1) reducing the levels of atmospheric greenhouse gases 

through large-scale manipulations (e.g., ocean fertilization or afforestation using 

non-native species); 2) exerting a cooling influence on Earth by reflecting sunlight 

(e.g., putting reflective particles into the atmosphere, putting mirrors in space, increasing surface reflectivity, or altering the amount or characteristics of clouds); and 

3) other large-scale manipulations designed to diminish climate change or its impacts (e.g., constructing vertical pipes in the ocean that would increase downward 

heat transport).’’

My expertise is in category 2, sometimes called ‘‘solar radiation management.’’ In 

particular, my work has focused on the idea of emulating explosive volcanic eruptions, by attempting to produce a stratospheric cloud that would reflect some incoming sunlight, to shade and cool the planet to counteract global warming. In this testimony, except where indicated, I will confine my remarks to this specific idea, and 

use the term ‘‘geoengineering’’ to refer to only it. I do this because it is the suggestion that has gotten the most attention recently, and because it is the one that I 

have addressed in my work. 

My personal view is that we need aggressive mitigation to lessen the impacts of 

global warming. We will also have to devote significant resources to adaptation to 

deal with the adverse climate changes that are already beginning. If geoengineering 

is ever used, it should be as a short-term emergency measure, as a supplement to, 

and not as a substitute for, mitigation and adaptation. And we are not ready to implement geoengineering now. 

The question of whether geoengineering could ever help to address global warming cannot be answered at this time. In our most recent paper (Supplementary Material 9) we have identified six potential benefits and 17 potential risks of stratospheric geoengineering, but a vigorous research program is needed to quantify each 

of these items, so that policy makers will be able to make an informed decision, by 

weighing the benefits and risks of different policy options. 

Furthermore, there has been no demonstration that geoengineering is even possible. No technology to do geoengineering currently exists. The research program 

needs to also evaluate various suggested schemes for producing stratospheric particles, to see whether it is practical to maintain a stratospheric cloud that would 

be effective at blocking sunlight.

Introduce the key scientific, regulatory, ethical, legal and economic challenges of geoengineering.

In Robock (2008a; Supplementary Material 4) I identified 20 reasons why 

geoengineering may be a bad idea. Subsequent work, summarized in Robock et al. 

(2009; Supplementary Material 9), eliminated three of these reasons, determined 

that one is still not well understood, but added one more reason, so I still have identified 17 potential risks of geoengineering. Furthermore, there is no current technology to implement or monitor geoengineering, should it be tested or implemented. 

Robock (2008b; Supplementary Material 5) described some of these effects, particularly on ozone. 

Key challenges of geoengineering related to the side effects on the climate system 

are that it could produce drought in Asia and Africa, threatening the food and water 

supply for billions of people, that it would not halt continued ocean acidification 

from CO2, and that it would deplete ozone and increase dangerous ultraviolet radiation. Furthermore, the reduction of direct solar radiation and the increase in diffuse radiation would make the sky less blue and produce much less solar power 

from systems using focused sunlight. Any system to inject particles or their precursors into the stratosphere at the needed rate would have large local environmental 

impacts. If society lost the will or means to continue geoengineering, there would 

be rapid warming, much more rapid than would occur without geoengineering. If a 
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series of volcanic eruptions produced unwanted cooling, geoengineering could not be 

stopped rapidly to compensate. In addition, astronomers spend billions of dollars to 

build mountain-top observatories to get above pollution in the lower troposphere. 

Geoengineering would put permanent pollution above these telescopes. 

Another category of challenges is unexpected consequences. No matter how much 

analysis is done ahead of time, there will be surprises. Some will make the effects 

less damaging, but some will be more damaging. Furthermore, human error is likely 

to produce problems with any sophisticated technical system. 

Ethical challenges include what is called a moral hazard—if geoengineering is 

perceived to be a solution for global warming, it will lessen the current gathering 

consensus to address climate change with mitigation. There is also the question of 

moral authority—do humans have the right to control the climate of the entire planet to benefit them, without consideration of all other species? Another ethical issue 

is the potential military use of any geoengineering technology. One of the cheapest 

approaches may even be to use existing military airplanes for geoengineering 

(Robock et al., 2009; Supplementary Material 9). Could techniques developed to control global climate forever be limited to peaceful uses? Other ethical considerations 

might arise if geoengineering would improve the climate for most, but harm some. 

Legal and regulatory challenges are closely linked to ethical ones. Who would end 

up controlling geoengineering systems? Governments? Private companies holding 

patents on proprietary technology? And whose benefit would they have at heart? 

Stockholders or the general public welfare? Eighty-five countries, including the 

United States, have signed the U.N. Convention on the Prohibition of Military or 

Any Other Hostile Use of Environmental 

Modification Techniques. It will have to be modified to allow geoengineering that 

would harm any of the signatories. And whose hand would be on the thermostat? 

How would the world decide on what level of geoengineering to apply? What if Canada or Russia wanted the climate to be a little warmer, while tropical countries and 

small island states wanted it cooler? Certainly new governance mechanisms would 

be needed. 

As far as economic challenges go, even if our estimate (Robock et al., 2009; Supplementary Material 9) is off by a factor of 10, the costs of actually implementing 

geoengineering would not be a limiting factor. Rather, the economic issues associated with the potential damages of geoengineering would be more important.

Major strategies for evaluating different geoengineering methods.

Evaluation of geoengineering strategies requires determination of their costs, benefits, and risks. Furthermore, geoengineering requires ongoing monitoring. As discussed below, a robust research program including computer modeling and engineering studies, as well as study of historical, ethical, legal, and social implications of 

geoengineering and governance issues is needed. Monitoring will require the reestablishment of the capability of measuring the location, properties and vertical distribution of particles and ozone in the stratosphere using satellites.

Broadly evaluate the geoengineering strategies you believe could be most 

viable based on these criteria.

I know of no viable geoengineering strategies. None have been shown to work to 

control the climate. None have been shown to be safe. However, the ones that have 

the most potential, and which need further research, would include stratospheric 

aerosols and brightening of marine tropospheric clouds, as well as carbon capture 

and sequestration. Carbon capture has been demonstrated on a very small scale. 

Whether it can be conducted on a large enough scale to have a measurable impact 

on atmospheric CO2 concentrations, and whether the CO2 can be sequestered efficiently and safely for a long period of time, are areas that need to be researched.

Identify the climate circumstances under which the U.S. or international 

community should undertake geoengineering.

For a decision to actually implement geoengineering, it needs to be demonstrated 

that the benefits of geoengineering outweigh the risks. We need a better understanding of the evolution of future climate both with and without geoengineering. 

We need to know the costs of implementation of geoengineering and compare them 

to the costs of not doing geoengineering. Geoengineering should only be implemented in response to a planetary emergency. However, there are no governance 

mechanisms today that would allow such a determination. Governance would also 

have to establish criteria to determine the end of the emergency and the ramping 

down of geoengineering. 
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Examples of climate circumstances that would be candidates for the declaration 

of a planetary emergency would include rapid melting of the Greenland or Antarctic 

ice sheets, with attendant rapid sea level rise, or a catastrophic increase in severe 

hurricanes and typhoons. Even so, stratospheric geoengineering should only be implemented if it could be determined that it would address these specific emergencies 

without causing worse problems. And there may be local means to deal with these 

specific issues that would not produce the risks of global geoengineering. For example, sea level rise could be addressed by pumping sea water into a new lake in the 

Sahara or onto the cold Antarctic ice sheet where it would freeze. There may be 

techniques to cool the water ahead of approaching hurricanes by mixing cold water 

from below up to the surface. Of course, each of these techniques may have its own 

unwelcome side effects. 

Right now there are no circumstances that would warrant geoengineering. This 

is because we lack the knowledge to evaluate the benefits, risks, and costs of 

geoengineering. We also lack the requisite governance mechanisms. Our policy right 

now needs to be to focus on mitigation, while funding research that will produce the 

knowledge to make such decisions about geoengineering in five or ten years.

Recommendations for first steps, if any, to begin a geoengineering research 

and/or governance effort.

In 2001, the U.S. Department of Energy issued a white paper (Supplementary Material 3) that called for a $64,000,000 research program over five years to look 

into a variety of suggested methods to control the climate. Such a coordinated program was never implemented, but there are now a few research efforts using climate models of which I am aware. In addition to my grant from the National 

Science Foundation, discussed below, I know of one grant from NASA to Brian Toon 

for geoengineering research and some work by scientists at the National Center for 

Atmospheric Research, funded by the Federal Government. In addition, there have 

been some climate modeling studies conducted at the United Kingdom Hadley Centre, and there is a new three-year project, started in July 2009, funded by the European Union for Ö1,000,000 ($1,500,000) for three years called ‘‘IMPLICC—Implications and risks of engineering solar radiation to limit climate change,’’ involving the 

cooperation of 5 higher educational and research institutions in France, Germany 

and Norway. 

In light of the importance of this issue, as outlined in Robock (2008b; Supplementary Material 5), I recommend that the U.S., in collaboration with other countries, embark on a well-funded research program to ‘‘consider geoengineering’s potential benefits, to understand its limitations, and to avoid ill-considered deployment’’ (as the American Meteorological Society says in Supplementary Material 2). 

In particular the American Meteorological Society recommends:

1) Enhanced research on the scientific and technological potential for 

geoengineering the climate system, including research on intended and unintended environmental responses.

2) Coordinated study of historical, ethical, legal, and social implications of 

geoengineering that integrates international, interdisciplinary, and 

intergenerational issues and perspectives and includes lessons from past efforts to modify weather and climate.

3) Development and analysis of policy options to promote transparency and 

international cooperation in exploring geoengineering options along with restrictions on reckless efforts to manipulate the climate system.

I support all these recommendations. Research under item 1) would involve stateof-the-art climate models, which have been validated by previous success at simulating past climate change, including the effects of volcanic eruptions. They would 

consider different suggested scenarios for injection of gases or particles designed to 

produce a stratospheric cloud, and evaluate the positive and negative aspects of the 

climate response— So far, the small number of studies that have been conducted 

have all used different scenarios, and it is difficult to compare the results to see 

which are robust. One such example is given in the paper by Rasch et al. (2008; 

Supplementary Material 7). Therefore, I am in the process of organizing a coordinated experiment among the different climate modeling groups that are performing 

runs for the Coupled Model Intercomparison Project, Phase 5, which will inform the 

next Intergovernmental Panel on Climate Change report. Once we agree on a set 

of standard scenarios, participation will depend on these different groups from 

around the world volunteering their computer and analysis time to conduct the experiments. Financial support from a national research program, in cooperation with 

other nations, will produce more rapid and more comprehensive results. 
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Another area of research that needs to be supported under topic 1) is the technology of producing a stratospheric aerosol cloud. Robock et al. (2009; Supplementary Material 9) calculated that it would cost several billion dollars per year to 

just inject enough sulfur gas into the stratosphere to produce a cloud that would 

cool the planet using existing military airplanes. Others have suggested that it 

would be quite a bit more expensive. However, even if SO2 (sulfur dioxide) or H2S 

(hydrogen sulfide) could be injected into the stratosphere, there is no assurance that 

nozzles and injection strategies could be designed to produce a cloud with the right 

size droplets that would be effective at scattering sunlight. Our preliminary theoretical work on this problem is discussed by Rasch et al. (2008; Supplementary Material 7). However, the research program will also need to fund engineers to actually 

build prototypes based on modification of existing aircraft or new designs, and to 

once again examine other potential mechanisms including balloons, artillery, and 

towers. They will also have to look into engineered particles, and not just assume 

that we would produce sulfate clouds that mimic volcanic eruptions. 

At some point, given the results of climate models and engineering, there may be 

a desire to test such a system in the real world. But this is not possible without 

full-scale deployment, and that decision would have to be made without a full evaluation of the possible risks. Certainly individual aircraft or balloons could be 

launched into the stratosphere to release sulfur gases. Nozzles can be tested. But 

whether such a system would produce the desired cloud could not be tested unless 

it was deployed into an existing cloud that is being maintained in the stratosphere. 

While small sub-micron particles would be most effective at scattering sunlight and 

producing cooling, current theory tells us that continued emission of sulfur gases 

would cause existing particles to grow to larger sizes, larger than volcanic eruptions 

typically produce, and they would be less effective at cooling Earth, requiring even 

more emissions. Such effects could not be tested, except at full-scale. 

Furthermore, the climatic response to an engineered stratospheric cloud could not 

be tested, except at full-scale. The weather is too variable, so that it is not possible 

to attribute responses of the climate system to the effects of a stratospheric cloud 

without a very large effect of the cloud. Volcanic eruptions serve as an excellent natural example of this. In 1991, the Mt. Pinatubo volcano in the Philippines injected 

20 Mt (megatons) of SO2 (sulfur dioxide) into the stratosphere. The planet cooled 

by about 0.5° C (1° F) in 1992, and then warmed back up as the volcanic cloud fell 

out of the atmosphere over the next year or so. There was a large reduction of the 

Asian monsoon in the summer of 1992 and a measurable ozone depletion in the 

stratosphere. Climate model simulations suggest that the equivalent of one 

Pinatubo every four years or so would be required to counteract global warming for 

the next few decades, because if the cloud were maintained in the stratosphere, it 

would give the climate system time to cool in response, unlike for the Pinatubo case, 

when the cloud fell out of the atmosphere before the climate system could react 

fully. To see, for example, what the effects of such a geoengineered cloud would be 

on precipitation patterns and ozone, we would have to actually do the experiment. 

The effects of smaller amounts of volcanic clouds on climate can simply not be detected, and a diffuse cloud produced by an experiment would not provide the correct 

environment for continued emissions of sulfur gases. The recent fairly large eruptions of the Kasatochi volcano in 2008 (1.5 Mt SO2) and Sarychev in 2009 (2 Mt 

SO2) did not produce a climate response that could be measured against the noise 

of chaotic weather variability. 

Some have suggested that we test stratospheric geoengineering in the Arctic, 

where the cloud would be confined and even if there were negative effects, they 

would be limited in scope. But our experiments (Robock et al., 2008; Supplementary 

Material 6) found that clouds injected into the Arctic stratosphere would be blown 

by winds into the midlatitudes and would affect the Asian summer monsoon. Observations from all the large high latitude volcanic eruptions of the past 1500 years, 

Eldgja ́ in 939, Laid in 1783, and Katmai in 1912, support those results. 

Topics 2) and 3) should also be part of any research program, with topic 3) dealing 

with governance issues. This is not my area of expertise, but as I understand it, 

the U.N. Convention on the Prohibition of Military or Any Other Hostile Use of Environmental Modification Techniques prohibits geoengineering if it will have negative effects on any of the 85 signatories to the convention (which include the U.S.). 

International governance mechanisms, probably through the United Nations, would 

have to be established to set the rules for testing, deployment, and halting of any 

geoengineering. Given the different interests in the world, and the current difficulty 

of negotiating mitigation, it is not clear to me how easy this would be. And any abrogation of such agreements would produce the potential for conflict. 

How much would a geoengineering research program cost? Given the continued 

threat to the planet from climate change, it is important that in the next decade 
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policy makers be provided with enough information to be able to decide whether 

geoengineering can be considered as an emergency response to dangerous climate 

change, given its potential benefits, costs, and risks. If the program is not well-funded, such answers will be long in coming. The climate modeling community is ready 

to conduct such experiments, given an increase in funding for people and computers. 

Funding should include support for students studying climate change as well as to 

existing scientists, and would not be that expensive. It should certainly be in, the 

range of millions of dollars per year for a 5–10 year period. I am less knowledgeable 

of what the costs would be for engineering studies or for topics 2) and 3). 

A geoengineering research program should not be at the expense of existing research into climate change, and into mitigation and adaptation. Our first goal 

should be rapid mitigation, and we need to continue the current increase in support 

for green alternatives to fossil fuels. We also need to continue to better understand 

regional climate change, to help us to implement mitigation and adapt to the climate change that will surely come in the next decades no matter what our actions 

today. But a small increment to current funding to support geoengineering will 

allow us to determine whether geoengineering deserves serious consideration as a 

policy option.

Describe your NSF-funded research activities at Rutgers University.

I am supported to conduct geoengineering research by the following grant: 

National Science Foundation, ATM–0730452, ‘‘Collaborative Research in Evaluation of Suggestions to Geoengineer the Climate System Using Stratospheric Aerosols 

and Sun Shading,’’ February 1, 2008—January 31, 2011, $554,429. (Includes $5000 

Research Experience for Undergraduates supplement.) 

I conduct research with Professors Georgiy Stenchikov and Martin Bunzl and students Ben Kravitz and Allison Marquardt at Rutgers, in collaboration with Prof. 

Richard Turco at UCLA, who is funded on a collaborative grant by NSF with separate funding. We conduct climate model simulations of the response to various scenarios of production of a cloud of particles in the stratosphere. We use a NASA climate model on NASA computers to conduct our simulations. We also have investigated the potential cost of injecting gases into the stratosphere that would react 

with water vapor to produce a cloud of sulfuric acid droplets. We calculated how 

much additional acid rain and snow would result when the sulfuric acid eventually 

falls out of the atmosphere. Prof. Turco focuses on the detailed mechanisms in the 

stratosphere whereby gases convert to particles. Prof. Bunzl is a philosopher. Together we are also examining the ethical dimensions of geoengineering proposals. 

We have published five peer-reviewed journal articles on our research so far, attached as Supplementary Material items 5–9, and Prof. Bunzl has published one additional peer-reviewed paper supported by this grant.

Delineate the precautionary steps that might be needed in the event of 

large scale testing or deployment.

First of all, there is little difference between large-scale testing and deployment. 

To be able to measure the climate response to a stratospheric cloud above the noise 

of chaotic weather variations, the injection of stratospheric particles would have to 

so large as that it would be indistinguishable from deployment of geoengineering. 

And it would have to last long enough to produce a measurable climate response, 

at least for five years. One of the potential risks of this strategy is that if it is perceived to be working, the enterprise will develop a constituency that will push for 

it to continue, just like other government programs, with the argument that jobs 

and business need to be protected. 

The world will have to develop a governance structure that can decide on whether 

or not to do such an experiment, with detailed rules as to how it will be evaluated 

and how the program will be ended. The current U.N. Convention on the Prohibition 

of Military or Any Other Hostile Use of Environmental Modification Techniques will 

have to be modified. 

Any large-scale testing or deployment would need to be first be evaluated thoroughly with climate model simulations. Climate models have been validated by simulating past climate change, including the effects of large volcanic eruptions. They 

will allow scientists to test different patterns of aerosol injection and different types 

of aerosols, and to thoroughly study the resulting spatial patterns of temperature, 

precipitation, soil moisture, and other climate responses. This information will allow 

the governance structure to make informed decisions about whether to proceed—

Any field testing of geoengineering would need to be monitored so that it can be 

evaluated. While the current climate observing system can do a fairly good job of 

measuring temperature, precipitation, and other weather elements, we currently 
51

have no system to measure clouds of particles in the stratosphere. After the 1991 

Pinatubo eruption, observations with the Stratospheric Aerosol and Gas Experiment 

II (SAGE II) instrument on the Earth Radiation Budget Satellite showed how the 

aerosols spread, but it is no longer operating. To be able to measure the vertical 

distribution of the aerosols, a limb-scanning design, such as that of SAGE II, is optimal. Right now, the only limb-scanner in orbit is the Optical Spectrograph and InfraRed Imaging System (OSIRIS), a Canadian instrument on Odin, a Swedish satellite. SAGE III flew from 2002 to 2006, and there are no plans for a follow on mission. A spare SAGE III sits on a shelf at a NASA lab, and could be used now. There 

is one Canadian satellite in orbit now with a laser, but it is not expected to last 

long enough to monitor future geoengineering, and there is no system to use it to 

produce the required observations of stratospheric particles. Certainly, a dedicated 

observational program would be needed as an integral part of any geoengineering 

implementation. 

These current and past successes can be used as a model to develop a robust 

stratospheric observing system, which we need anyway to be able to measure the 

effects of episodic volcanic eruptions. The recent fairly large eruptions of the 

Kasatochi volcano in 2008 and Sarychev in 2009 produced stratospheric aerosol 

clouds, but the detailed structure and location of the resulting clouds is poorly 

known, because of a lack of an observing system.

BIOGRAPHY FOR ALAN ROBOCK

Dr. Alan Robock is a Professor II (Distinguished Professor) of climatology in the 

Department of Environmental Sciences at Rutgers University and the associate director of its Center for Environmental Prediction. He also directs the Rutgers Undergraduate Meteorology Program. He graduated from the University of Wisconsin, 

Madison, in 1970 with a B.A. in Meteorology, and from the Massachusetts Institute 

of Technology with an S.M. in 1974 and Ph.D. in 1977, both in Meteorology. Before 

graduate school, he served as a Peace Corps Volunteer in the Philippines. He was 
52

a professor at the University of Maryland, 1977–1997, and the State Climatologist 

of Maryland, 1991–1997, before moving to Rutgers in 1998. 

Prof. Robock has published more than 250 articles on his research in the area of 

climate change, including more than 150 peer-reviewed papers. His areas of expertise include geoengineering, the effects of volcanic eruptions on climate, the impacts 

of climate change on human activities, detection and attribution of human effects 

on the climate system, regional atmosphere-hydrology modeling, soil moisture, and 

the climatic effects of nuclear weapons. 

Professor Robock is currently supported by the National Science Foundation to do 

research on geoengineering. He has published five peer-reviewed journal articles on 

geoengineering, in 2008 and 2009. He was a member of the committee that drafted 

the July 2009 American Meteorological Society Policy Statement on Geoengineering 

the Climate System. He has convened sessions on geoengineering at two past American. Geophysical Union Fall Meetings, and is the convener of sessions on 

geoengineering to be held at meetings of the American Association for the Advancement of Science and European Geosciences Union in 2010. 

His honors include being a Fellow of the American Meteorological Society, a Fellow of the American Association for the Advancement of Science (AAAS), and a participant in the Intergovernmental Panel on Climate Change, which was awarded the 

Nobel Peace Prize in 2007. He was the American Meteorological Society/Sigma Xi 

Distinguished Lecturer for the academic year 2008–2009. 

Prof. Robock was Editor of the Journal of Geophysical Research—Atmospheres

from April 2000 through March 2005 and of the Journal of Climate and Applied Meteorology from January 1985 through December 1987. He was Associate Editor of 

the Journal of Geophysical Research -Atmospheres from November 1998 to April 

2000 and of Reviews of Geophysics from September 1994 to December 2000, and is 

once again serving as Associate Editor of Reviews of Geophysics, since February, 

2006. 

Prof. Robock serves as President of the Atmospheric Sciences Section of the American Geophysical Union and Chair-Elect of the Atmospheric and Hydrospheric 

Sciences Section of the American Association for the Advancement of Science. He 

has been a Member Representative for Rutgers to the University Corporation for Atmospheric Research since 2001, and serves on its President’s Advisory Committee 

on University Relations. Prof Robock was a AAAS Congressional Science Fellow in 

1986–1987, serving as a Legislative Assistant to Congressman Bill Green (R–NY) 

and as a Research Fellow at the Environmental and Energy Study Conference.
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Chairman GORDON. Thank you, Dr. Robock. Dr. Fleming, you are 

recognized. 

STATEMENT OF DR. JAMES FLEMING, PROFESSOR AND DIRECTOR, SCIENCE, TECHNOLOGY AND SOCIETY PROGRAM, 

COLBY COLLEGE 

Dr. FLEMING. Thank you, Mr. Chairman, Ranking Member Hall, 

and Members of the Committee on Science and Technology. I want 

to talk about history, and one of my epigraphs is that in facing unprecedented challenges, which I think we are, it is good to seek historical precedents. History matters, and informed policy decisions 

are going to require interdisciplinary, international, and 

intergenerational perspectives. So I applaud your international 

move, and I would like to make a case for intergenerational perspectives as well that are informed by history. 

I was once asked when humans first became concerned about climate change, and I immediately responded, in the Pleistocene. 

That is, our whole history comes out of ice age variations of climate, and all of human history lies within the last interglacial era, 

which was 12,000 years ago. We have experienced huge variations 

in climate, up to 27 degrees Fahrenheit, and I am sure the early 

humans had important tribal councils, too, to talk about these 

things, although they didn’t have mitigation yet as an option. 

European explorers and early American settlers were surprised 

that the New World was so much colder than the areas of the same 

latitude in Europe. For example, Washington D.C. is on the same 

parallel as Lisbon, Portugal. Colonists worked to improve the climate by cutting the forest, tilling the soil, and draining the 

marshes. Benjamin Franklin thought this was possible. Thomas 

Jefferson thought it was actually happening. He called for an index 

of the American climate, which is one reason we have great weather records in this country, to document the changes being caused 

by human intervention. 

I will show a few pictures. 

[The information follows:]
69

The quest to control nature, including the sky, is deeply rooted 

in the history of western science. Some climate engineers claim 

they are the first generation to propose the deliberate manipulation 

of the planetary environment, but history says otherwise. In the 

1830s, America’s first national meteorologist, James Espy, who 
70

worked for the U.S. Army Surgeon General, advocated large-scale 

engineering proposals to emulate ‘‘artificial volcanoes.’’ He proposed 

lighting huge fires each week—he preferred Sunday evenings—all 

along the Appalachian Mountains. Each week he was going to 

make it rain and control and enhance the Nation’s rainfall. Espy 

argued that the heated updrafts would trigger rain that would not 

only eliminate droughts but also temperature extremes and would 

render the air healthy by clearing it of miasmas. A popular writer 

at the time, Eliza Leslie, pointed out that manufactured weather 

control would generate more problems than it solved and would 

satisfy no one. This is 1842. 

The image of the technocrat pulling the levers of weather control 

appeared on the cover of Collier’s Magazine in 1954. We were in 

a weather control race with the Soviet Union at the time, and an 

Air Force general had just announced to the press that the nation 

that controls the weather will control the world. The magazine article inside, by President Eisenhower’s Weather Advisor, Harold 

Orville, provided detailed ways of conducting weather warfare. A 

year later, the noted Princeton mathematician, Johnny Von Neumann, in an article called, Can We Survive Technology?, wrote that 

climate control through managing solar radiation was not necessarily a rational undertaking. In his opinion, climate control 

could alter the entire globe, shatter the existing political order, 

merge each nation’s affairs with every other, and lend itself to 

forms of warfare as yet unimagined. He compared climate control 

to the threat of nuclear proliferation. 

[The information follows:]

Here, Archimedes is acting as a geoengineer and technology is 

his lever, but where is he standing and where will the earth roll 

if tipped? Geoengineering is not cheap since we don’t know the 

side-effects. Quoting Ron Prinn of MIT, ‘‘How do you engineer a 

system you don’t understand?’’ While some argue that we can control the temperature of the globe, ironically, at a recent NASA 
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meeting on the topic of managing solar, a meeting coordinator 

apologized for not being able to control the temperature of the 

room. Think about it. 

[The information follows:]

This is Hurricane King, 1947, when Project Cirrus intervened 

and seeded it. They wanted to announce to the press that they can 

control hurricanes, but basically they cancelled the press conference when it came ashore and devastated Savannah, Georgia. 

Other diplomatic disasters include Project Stormfury in the 

1960s where Fidel Castro accused America of cloud seeding over 

Cuba and in Vietnam, Operation Popeye, when the UN subsequently outlawed hostile use of weather modification. 

People have said that climate control is not a good idea. Harry 

Wexler, head of research at the Weather Bureau, said this in 1962, 

and just two years ago, Bert Bolin, the first chair of the IPCC, 

wrote that the political implications of geoengineering are largely 

impossible to assess and it is not a viable solution because in most 

cases, it is an illusion to assume that all possible changes can be 

foreseen. Climate change is simple. We should do the right thing. 

Climate is complex. It involves oceans and atmospheres, ice sheets 

and now monsoons, so studying the human dimension is essential. 

We need the interdisciplinary, international and intergenerational 

emphasis. 

Thank you for your time. 
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[The prepared statement of Dr. Fleming follows:]

PREPARED STATEMENT OF JAMES FLEMING

Thank you Mr. Chairman, Ranking Member Hall, and Members of the Committee 

on Science and Technology for the opportunity to appear before you to provide testimony on Geoengineering: Assessing the Implications of Large-Scale Climate Intervention. 

I am a historian of science and technology with graduate training in and life-long 

connections to the atmospheric sciences, and the founding president of the International Commission on History of Meteorology. I have just written a book on the 

history of weather and climate control, and I am currently working to connect the 

history of science and technology with public policy. I have been asked to provide 

a general historical context for geoengineering as a political challenge and to recommend first steps toward effective international collaboration on geoengineering 

research and governance.

Introduction

I would like to state my conclusions in advance, which are all based on the 

premise that history matters:

First, a coordinated interdisciplinary—effort is needed to study the historical, 

ethical, legal, political, and societal aspects of geoengineering and to 

make policy and governance recommendations. This is one conclusion 

of the American Meteorological Society’s 2009 Policy Statement on 

Geoengineering.

Second, an international—‘‘Working Group 4’’ on historical, social, and cultural 

dimensions of climate change in general and geoengineering in particular should be added to the Intergovernmental Panel on Climate 

Change (IPCC).

Third, a robust intergenerational—component of training and participation, especially by young people, should be included in these efforts.

That is to say climate change is not quintessentially a technical issue. It is a 

socio-cultural and technical hybrid, and our effective response to it must be historically and technically informed, interdisciplinary in nature, international in scope, 

and intergenerational in its inclusion of graduate, undergraduate, and younger students.

A year later, in a prominent article titled, ‘‘Can We Survive Technology?’’ the 

noted Princeton mathematician and pioneer in computerized weather forecasts and 

climate models John von Neumann referred to climate control through managing 
73

solar radiation as a thoroughly ‘‘abnormal’’ industry that could have ‘‘rather fantastic effects’’ on a scale difficult to imagine. He pointed out that altering the climate of specific regions or purposefully triggering a new ice age were not necessarily 

rational undertakings. Tinkering with the Earth’s heat budget or the atmosphere’s 

general circulation ‘‘will merge each nation’s affairs with those of every other more 

thoroughly than the threat of a nuclear or any other war may already have done.’’ 

In his opinion, climate control could lend itself to unprecedented destruction and to 

forms of warfare as yet unimagined. It could alter the entire globe and shatter the 

existing political order. He made the Janus-faced nature of weather and climate control clear. The central question was not ‘‘What can we do?’’ but ‘‘What should we 

do?’’ This was the ‘‘maturing crisis of technology’’ for von Neumann, a crisis made 

more urgent by the rapid pace of progress.

First of all, a male hand is on the thermometer, the hand is god-like in scale, and 

the thermostat is ‘‘nowhere,’’ but perhaps in outer space. The temperature of 73 F 

is being turned back to 54, or 5 degrees cooler than the long-term planetary average 

of 59 F. Looking closely at the center of dial, the thermometer is centered on 

Roswell, New Mexico, which I take to be symbolic. 

An emergent property of the MIT meeting was that the social science component 

the voices calling for the study of history, politics, and governance of geoengineering 

convinced more people than those engaged in geo-scientific speculation of a more 

technical nature. It is an emerging view in climate studies that humanities and governance perspectives are sorely needed. This was also clear this past summer at 

‘‘America’s Climate Choices’’ meeting on geoengineering, sponsored by Congressman 

Mollohan of West Virginia and convened by the National Academies of Science.
74

The image of Archimedes is sometimes invoked by geoengineers with the assertion that our technological levers are now getting long enough and powerful enough 

to move the Earth. But if Archimedes is a supposed geoengineer, where is he standing? And where will the Earth roll if tipped? With what consequences? Widespread 

discussions of ‘‘tipping points,’’ have involved the physical climate system or public 

opinion, but it is important to remember that the geoengineering community has 

also passed a tipping point, and many of them actually wish to try it! But while 

some argue we can control the temperature of the globe, ironically, at a recent 

NASA meeting in 2006 on the topic of ‘‘Managing Solar Radiation,’’ a meeting coordinator apologized for not being able to control the temperature of the room.

A Geopolitical Perspective on Aerosol Haze

The aerosol haze from dust storms, industrial sulfate emissions, and biomass 

burning is widely believed have a local cooling effect by reflecting sunlight and by 

making clouds brighter in the troposphere, below about 30,000 feet. As we clean up 

industrial pollution and reduce biomass burning, the warming effects of greenhouse 

gases may become more pronounced. Since the early I960s some geoengineers have 

repeatedly proposed injecting a sulfate aerosol haze into the high, dry, and stable 
75

stratosphere, where it would spread worldwide and have global cooling effects that 

might not fully offset greenhouse warming, might have unwanted side effects that 

might not be welcomed by all nations.

Although the heating effect of the major greenhouse gases is well known, the level 

of scientific understanding of the cooling effect of aerosols ranges from ‘‘low’’ to ‘‘very 

low.’’ Geoengineers propose to transfer this cooling effect, and the lack of understanding about it, to the stratosphere, where it will become a global rather than a 

local process, again with likely unwanted side effects that others will address.

What’s Wrong with Climate Engineering? (the short list)

1. We don’t have the understanding (Ron Prinn, MIT).

2. We don’t have the technology (Brian Toon, Univ. of Colorado).

3. We don’t have the political capital, wisdom, or will to govern it.

4. It is not ‘‘cheap’’ since the side effects are unknown.

5. It poses a moral hazard, reducing incentives to mitigate.

6. It could be attempted unilaterally, or worse, proliferate.

7. It could be militarized, and learning from history it likely would be militarized.

8. It could violate a number existing treaties such as ENMOD (1978).

9. It does nothing to solve ocean acidification.

10. It will alter fundamental human relationships to nature.

What Role for History?

We have known this for a long time. Some climate engineers claim they are the 

‘‘first generation’’ to propose the deliberate manipulation of the planetary environment. History says otherwise. In the 1790s Thomas Jefferson called for an ‘‘index’’ 

of the American climate to document its changes being effected by the clearing of 

the forests and the draining of the marshes. In the 1830s the first serious large 

scale engineering proposal to emulate ‘‘artificial volcanoes’’ was advanced by James 

Espy, the distinguished theorist of convection as the cause of rain who was employed by the U.S. Army as the first national meteorologist. Espy proposed lighting 

huge fires all along the Appalachian Mountains to control and enhance the nation’s 

rainfall, arguing that the heat, updrafts would trigger rain and would not only 

eliminate droughts, but also heat waves and cold snaps, rendering the air healthy 

by clearing it of miasmas. A popular writer, Eliza Leslie, immediately pointed out 

that manufactured weather control would generate more problems than it solved. 

In 1946, Nobel Laureate Irving Langmuir believed he and his team at the General 

Electric Corporation had discovered means of controlling the weather with cloud 

seeding agents such as dry ice and silver iodide. A year later, in conjunction with 

the U.S. military, they sought to deflect a hurricane from its path. After seeding, 

but not because of seeding, the hurricane veered due to what were later determined 

to be natural steering currents and smashed ashore on Savannah, Georgia. The 

planned press conference was cancelled, but Langmuir continued to claim he could 
76

control hurricanes, influence the nation’s weather, and even planned to seed the entire Pacific basin in a mega-scale experiment intended to generate climate-scale effects.

Commercial and military interests inevitably influence what scientists might consider purely technical issues. Agricultural interests drove the nineteenth-century 

charlatan rainmakers in the American west as well as commercial cloud seeding 

since the 1940s. In the early Cold War era, as mentioned earlier, the military 

sought to control clouds and storms as weapons and in the service of an all-weather 

air force. There was a ‘‘weather race’’ with the Russians and secret cloud seeding 

in Vietnam. The 1978 United Nations Convention on the Prohibition of Military or 

any other Hostile Use of Environmental Modification Techniques (ENMOD), a landmark treaty, may have to be revisited soon to avoid or at least try to mitigate possible military or hostile use of climate control. 

In 1962 Harry Wexler, Head of Research at the U.S. Weather Bureau, shown here 

in the Oval Office, used computer models and satellite observations to study techniques to change Earth’s heat budget. Wexler helped pen Kennedy’s notable line, 

‘‘We choose to go to the moon in this decade and do the other things . . .’’ Wexler 

was in charge of ‘‘the other things,’’ such as the World Weather Watch and ways 

to influence or control weather and climate. It was Wexler, in the era of JFK (not 

Paul Crutzen in 2006) who first claimed climate control was now ‘‘respectable to 

talk about,’’ even if he considered it quite dangerous and undesirable. Wexler described techniques to warm or cool the planet by two degrees. He also warned, notably, that the stratospheric ozone layer was vulnerable to inadvertent or intentional 

damage, perhaps by hostile powers, from small amounts of a catalytic agent such 

as chlorine or bromine.
77

Here is an important discovery, made just next door in the Library of Congress. 

It is Harry Wexler’s handwritten note of 1962 that reads (substituting words for 

symbols), ‘‘Ultraviolet light decomposes ozone into atomic oxygen. In the presence 

of a halogen like bromine or chlorine, atomic oxygen becomes molecular oxygen and 

so prevents ozone from forming. 100,000 tons of bromine could theoretically prevent 

all ozone north of 65° N from forming.’’ Recently, I have been in correspondence 

with three notable ozone scientists about Wexler’s early work: Nobel Laureates 

Sherwood Rowland, Paul Crutzen, and current U.S. National Academy of Sciences 

President Ralph Cicerone. They are uniformly interested and quite amazed by 

Wexler’s insights and accomplishments.

Wexler wrote in 1962, ‘‘[Climate control] can best be classified as ‘‘interesting hypothetical exercises’’ until the consequences of tampering with large-scale atmospheric events can be assessed in advance. Most such schemes that have been advanced would require colossal engineering feats and contain the inherent risk of ir-
78

remediable harm to our planet or side effects counterbalancing the possible shortterm benefits.’’ This is still true today.

Today’s science is tomorrow’s history of science

‘‘In facing unprecedented challenges, it is good to seek historical precedents,’’ this 

is the epigraph of my new book Fixing the Sky: The checkered history of weather 

and climate control. History matters—it shapes identity and behavior; it is not just 

a celebratory record of inevitable progress; and its perspective should inform sound 

public policy. Each of our personal identities is the sum of our integrated past, including personal and collective memories, events, and experiences. It is not just who 

and where we are now, how we feel today, and what we had for breakfast. Applied 

to geoengineering, we should base our decision-making not on what we think we can 

do ‘‘now’’ and in the near future. Rather our knowledge is shaped by what we have 

and have not done in the past. Such are the grounds for making informed decisions. 

Students of climate dynamics who are passionate about climate change would be 

well-served to study science dynamics (history), since on decades to centuries and 

millennial time scales ideas and technologies have changed as dramatically or perhaps more dramatically than the climate system itself. 

History can provide scholars in other disciplines with detailed studies of past 

interventions by rainmakers and climate engineers as well as structural analogues 

from a broad array of treaties and interventions. Only in such a coordinated fashion, 

in which researchers and policymakers participate openly, can the best options 

emerge that promote international cooperation, ensure adequate regulation, and 

avoid the inevitable adverse consequences of rushing forward to fix the sky. 

Climate change is simple, and we all should seek ways of having less impact on 

the planet though a ‘‘middle course’’ of mitigation and adaptation that is amenable 

to all, reasonable, practical, equitable, and effective. But the climate system is extraordinarily complex, perhaps the most complex system ever modeled or observed, 

with the most important consequences imaginable for life and ecosystems. At best 

we can only apprehend climate change, with three senses of the word apprehension 

implied: (1) awareness and understanding, (2) anticipation, dread, fear, and (3) 

intervention and control. Certainly clouds, oceans, ice sheets and other factors make 

it more complex. But the wildest of the wild cards in the system is the human dimension, so studying that is absolutely essential.

Recommendations

I repeat my recommendations to the committee. We need:

1. A coordinated and autonomous interdisciplinary effort to study the historical, 

ethical, legal, political, and societal aspects of geoengineering and to make 
79

policy and governance recommendations, not as an afterthought and not necessarily within an existing scientific society.

2. An international ‘‘Working Group 4’’ on historical, social, and cultural dimensions of climate change in general and geoengineering in particular, perhaps 

under the auspices of the IPCC.

3. A robust intergenerational component of training and participation in such 

efforts.

In these ways I believe history can effectively inform public policy. Thank you for 

your attention.

Selected References:

Fleming, James Rodger. Fixing the Sky: The checkered history of weather and climate control. Columbia University Press, 2010.

Fleming, James Rodger. ‘‘The Climate Engineers: Playing God to Save the Planet,’’ 

Wilson Quarterly (Spring 2007): 46–60. http://www.colby.edu/sts/

climateengineers.pdf.

Fleming, James Rodger. ‘‘The Pathological History of Weather and Climate Modification: Three cycles of promise and hype,’’ Historical Studies in the Physical 

Sciences 37, no. 1 (2006): 3–25. http://www.Colby.edulsts/

06¥fleming¥pathological.pdf

BIOGRAPHY FOR JAMES FLEMING

James Rodger Fleming is Professor of Science, Technology, and Society at Colby 

College. He earned degrees in astronomy (B.S., Penn State), atmospheric science 

(M.S. Colorado State), and history (M.A. and Ph.D. Princeton) and worked in atmospheric modeling, airborne observational programs, consulting meteorology, and as 

historian of the American Meteorological Society. Professor Fleming has held major 

fellowships from the Smithsonian Institution, the National Science Foundation, the 

National Endowment for the Humanities, and the American Association for the Advancement of Science. He has been a visiting scholar at MIT, Harvard, Penn State, 

the National Air and Space Museum, the National Academy of Sciences, and the 

Woodrow Wilson International Center for Scholars. 

Awards and honors include election as a Fellow of the AAAS ‘‘for pioneering studies on the history of meteorology and climate change and for the advancement of 

historical work within meteorological societies,’’ participation as an invited contributing author to the Intergovernmental Panel on Climate Change, appointment to 

the Charles A. Lindbergh Chair in Aerospace History by the Smithsonian Institution, the Roger Revelle Fellowship in Global Stewardship by the AAAS, and a number of named lectureships including the Ritter at Scripps Institution of Oceanography, the Vetelsen at the University of Rhode Island, and the Gordon Manly 

Lectureship of the Royal Meteorological Society. 

He is the author of Meteorology in America, 1800–1870 (Johns Hopkins, 1990), 

Historical Perspectives on Climate Change (Oxford, 1998), The Callendar Effect

(American Meteorological Society, 2007), and his latest, Fixing the Sky: The Checkered History of Weather and Climate Control (Columbia University Press, 2010). Recent co-edited volumes include Intimate Universality (Science History/U.S.A., 2006), 

Globalizing Polar Science (Palgrave, 2010), and Osiris 26 (forthcoming) on climate. 

He is currently working to link the local and global in the history of Earth system 

science and to connect the history of science and technology with public policy. 

Professor Fleming was the founder and first president of the International Commission on History of Meteorology and associate editor of the New Dictionary of Scientific Biography, He currently serves as editor-in-chief of History of Meteorology,

domain editor for Wiley Interdisciplinary Reviews on Climate, history editor of the 

Bulletin of the American Meteorological Society, and member of the history committee of the American Meteorological Society and the American Geophysical Union. 

Jim is a resident of China, Maine (not Mainland China!) with his wife Miyoko. 

Together they raised two sons. He enjoys fishing, good jazz, good BBQ, seeing students flourish, and building the community of historians of the geosciences. ‘‘Nothing is really work unless you would rather be doing something else.’’

DISCUSSION

Chairman GORDON. Thank you, Dr. Fleming. At this point, we 

will begin the first round of questions, but first I would like to give 
80

a premise. Listening to the panel makes me think that for most 

people, this is like coming in after the intermission to Mr. Hall’s 

movie about the elephants, and that we might want to give a little 

bit more of a premise. And I would really advise that anyone that 

has an interest in this issue to review the Royal Society’s report. 

It is very good. 

I was thinking about giving Mr. Hall the two-page summary, but 

I didn’t want to overwhelm him. So Professor Shepherd——

Mr. HALL. You would have had to read it to me. 

THE ERUPTION OF MT. PINATUBO: NATURAL SOLAR

RADIATION MANAGEMENT

Chairman GORDON. Professor Shepherd, just quickly, would you 

sort of remind everyone about the volcano in Pinatubo in 1991 and 

what happened? I think that is a good foundation for everyone to 

know. 

Dr. SHEPHERD. Yes, thank you. The volcano emitted a large 

amount of sulfur dioxide, amongst other things, some of which 

made its way to the stratosphere, and the result of this was the 

formation of a natural sulfate-based aerosol that spread very rapidly around the world and lasted for a couple of years, causing a 

fall in temperature of approximately 1° degree Fahrenheit for a 

couple of years. 

So this gives us some confidence that aerosols in the stratosphere 

do have a cooling effect and that the quantities of material required to do this are not unthinkably large. However, volcanoes, of 

course, emit a lot of other stuff, as well as sulfur dioxide, and so 

they are not a perfect analogue. And one of the other issues in relation to——

Chairman GORDON. I just wanted you to sort of point out that 

really nature has already given us somewhat of a model and this 

is not completely not out of line. 

Mr. HALL. I don’t really understand it yet. 

STRUCTURING A RESEARCH INITIATIVE

Chairman GORDON. I am going to give the panel some questions 

to take home with you, and I would like your response later. But 

let us just start a discussion if we could today because if we are 

looking at a research program, I would like to get a little better 

idea of what we should do. So let me put out some questions for 

the panel and get some reaction, and again, I would like for you 

to take it back and respond to us later. 

What would be the critical features of such a program? Would 

there be just one coordinated program in the United States? Which 

U.S. agencies would have to be involved from the start and which 

would need to play a later role? What scale of investment would 

be necessary, both initially and in the long term, and what kind 

of expertise would be required? I will later ask about the international implications but I would like to get your thoughts on a research program here in the United States. Who wants to start? 

Yes, sir. Dr. Fleming? 

Dr. FLEMING. I think based on what I said, we would have to 

have more humanists involved, a lot more social science compo-
81

nent, and I know that the National Academy has done things, but 

it is the National Academy of Science. And so I would like to recommend that we go multi-agency but include not only technical 

outfits in the discussion. 

Chairman GORDON. We will just go down the hall. Professor 

Shepherd and then Caldeira and then Lane and then Robock? 

Professor SHEPHERD. Yes, I would suggest that the program has 

to be international and that it should not focus exclusively on one 

technology and specifically that it should not focus exclusively on 

solar radiation management, because that is a technology which requires you to maintain your activity for as long as the greenhouse 

gases stay in the atmosphere, which is several centuries to a thousand years. And it is not clear that human society has the ability 

to sustain an activity on that time scale. 

So I think it would be very dangerous to start solar radiation 

management without having figured out your exit strategy, and 

your exit strategy would almost certainly include one or other of 

the carbon dioxide removal methods. So I would suggest that a 

small portfolio of methods of both of these types should be researched in parallel. 

Chairman GORDON. Dr. Caldeira? 

Dr. CALDEIRA. I would like to suggest that we should be thinking 

in terms of several research programs, each multi-agency in character but led by different agencies. If we separate the solar radiation management proposals from the carbon dioxide removal proposals, I think the solar radiation management proposals, the research, should perhaps be led by the National Science Foundation 

[NSF], possibly the National Aeronautics and Space Administration 

[NASA]. 

On the carbon dioxide removal, approaches again could be divided into two major classes. Some are essentially growing plants 

and burying the organic carbon made by plants. We already have 

some research programs into growing new forests and similar techniques. And those programs could perhaps be expanded to encompass a broader range of biologically based methods to remove carbon dioxide from the atmosphere. 

The Department of Energy is already leading projects to remove 

carbon dioxide from gases coming out of power plants. Those programs could be expanded to also consider removal of gases from the 

atmosphere. And so I think there is at least three separate programs, and some of them might involve expansion of existing programs on the carbon dioxide removal side, but there is really no 

program at all on the solar radiation management side. And I personally would like to see NSF probably lead it, although NASA 

might make sense as well. 

Chairman GORDON. Let us move to Mr. Lane. 

Mr. LANE. I would suggest that the solar radiation management—first of all, let me agree with Dr. Shepherd that I think 

there ought to be research in both families, both air capture and 

solar radiation management. However, solar radiation management 

offers much larger economic payoffs potentially and a much greater 

ability to reverse rapid, highly destructive climate change should 

that occur. Therefore, I guess I would reverse Dr. Shepherd’s judgment of priorities and say that of the two approaches, solar radi-
82

ation management deserves more attention, and as Dr. Caldeira 

has suggested, it is not really receiving any support from the U.S. 

Government at this time. It is clearly the sort of problem that is 

going to require multiple agency inputs and poses a very difficult 

organizational challenge for combining science and engineering. 

Chairman GORDON. I am going to let everybody respond in writing later, but Dr. Robock, if you would maybe just quickly close us. 

Dr. ROBOCK. First of all, I would like to mention that although 

the Pinatubo volcanic eruption cooled the planet, it also produced 

drought in Asia and Africa. It destroyed ozone, and it reduced solar 

radiation generation from direct solar radiation by 30 percent in 

those technologies that were developing. So it is a lesson of efficacy 

but also of problems. 

I think that research into solar radiation management needs to 

be done in a coordinated way, internationally, with climate models. 

The National Science Foundation should probably take the lead in 

the United States along with the National Oceanic and Atmospheric Administration [NOAA] and NASA. There also needs to be 

a research program to the technology. Can we actually get particles 

into the stratosphere, and probably NASA, the—Aeronautics, and 

the Department of Defense might be looking into the technology of 

it, whether it is possible. 

Chairman GORDON. I thank you. I now yield to Mr. Hall for rebuttal. 

Mr. HALL. I always come out second on that one when you are 

the Chairman. You have got the gavel. 

I will be serious with you because I appreciate you and I appreciate your backgrounds and many years of studying and the gifts 

you have made to this country, and your very appearance here 

today makes me even more appreciative of you. I especially like Dr. 

Shepherd, Professor Shepherd, because he at least discussed global 

warming and he added the term cost to it, and that is what we 

can’t get hardly anybody to talk about, who is going to pay it or 

how much China is going to continue to pollute the world and not 

pay a dollar and then increase it on an increasing ratio. So thank 

you for that. I agree with you on that. 

I don’t disagree with you on anything you have said, I just don’t 

fully understand it. But he has given me the right to write you, 

and you will be hearing from me. Thank you. 

THE POTENTIAL EFFICACY OF GREENHOUSE GAS

MITIGATION

Mr. Lane, you said you advocate research and not deployment, 

I guess that is what I am trying to say. Would you expand on your 

comment and your testimony that a steep decline in greenhouse 

gas emissions may well cost more than the perceived value of the 

benefits? And let me say before that, we had a study, I chaired one 

of the committees one time when we were studying and we studied 

about asteroids. A professor told us about volcanoes, but we were 

studying asteroids and the danger and trying to get an international thrust on them. We got no help on that because we had 

I think about $1.5 million budget on that, and that was a couple 

of brilliant people and their workers, co-workers with them. But we 

learned during that hearing something that none of the group 
83

knew, including the chairman, and that was me, that an asteroid 

just missed the earth by five minutes some time in 1987 or 1988. 

So I think this is worthwhile. And I was just spoofing the Chairman. He is so good-natured. He is the only Chairman I can kid like 

that. 

But go ahead now and answer me, if you would, Mr. Lane. 

Mr. LANE. Yes, sir. It seems that the last 20 years have shown 

not only that it is difficult to get agreement on greenhouse gas controls, but that that is happening for very clear reasons. China and 

India both have very rapidly growing emissions, and yet it is clear 

from the way their governments are dealing with the negotiations 

that they do not perceive greenhouse gas emissions reductions, at 

least not steep ones, as being in their national interest. And both 

of those countries are too powerful to coerce, and the cost of bribing 

them to reduce emissions when they don’t feel that it is in their 

national interests are likely to be prohibitively high. I don’t want 

to give the impression that I believe that we can go on emitting 

greenhouse gases at ever-increasing rates. I don’t. I think eventually controls are going to be essential, but I really strongly believe 

that the conditions are not in place yet for a global agreement on 

significantly reducing emissions. And until those conditions are in 

place, there really isn’t very much that the United States can do 

to change the global trajectory of emissions. 

RESEARCH AND DEVELOPMENT BEFORE APPLICATION

Mr. HALL. Well, I thank you for that, and also I guess I would 

ask you, your testimony seemed to suggest at the time that there 

is R&D and not implementation. Are there entities, organizations 

or countries that see an urgent need for implementation versus the 

process of R&D? I know most of the really rabid advocates of global 

warming mention everything but the cost and mention everything 

but the fact that China I think every six days are spewing—not 

using clean coal. And I think we will fall back on coal one day, we 

are going to have to. But it has to be clean coal. But they are increasing again I say on an increasing ratio the damage to the earth 

without paying anything. That goes for them, that goes for Russia, 

it goes for India, it goes for Mexico, and it could go on and on of 

those that want the benefits of the work that you probably all believe in but don’t want to participate in the cost. One or the others 

of you made mention of that. I will let you have whatever—I think 

I have may be two seconds left, but if you can do your best to give 

me——

Mr. LANE. I do support R&D rather than deployment. Dr. Robock 

is absolutely right. We don’t have the technology yet to do deployment, nor would it be prudent. For me personally, if I were going 

to put my bet on where to do R&D in the U.S. Government, along 

with NSF, as that Dr. Caldeira mentioned, I would suggest that 

DARPA [Defense Advanced Research Projects Agency] might have 

a role. 

Mr. HALL. Thank you. 

Chairman GORDON. Thank you, Mr. Hall. I think we can submit 

unanimously that this panel would say that there should be no deployment, only research. I don’t think you are going to find anybody that is going to disagree with that. 
84

Dr. Baird is recognized. 

THE DIRE NEED FOR MITIGATION AND BEHAVIOR CHANGE

Mr. BAIRD. Thank you, Mr. Chairman. I thank our panelists. 

Roughly, how much CO2 do human beings put into the air, anthropogenic CO2 on a daily basis? Anyone have an estimate of that or 

annual, whatever number? Dr. Caldeira? 

Dr. CALDEIRA. The average American puts out something like 

their own average body weight each day in the form of carbon dioxide. So something like 150 pounds of CO2 per person per day in the 

United States. 

Mr. BAIRD. Times 300 million people? 

Dr. CALDEIRA. Right, times 365 days a year. 

Mr. BAIRD. Mr. Robock, did you want to add to that? The reason 

I ask the question is, we are doing geoengineering on a massive 

scale. If 100 years ago somebody had said, hey, here is a bright 

idea. We should promote a plan to put that much carbon into the 

air—And Dr. Caldeira, I commend you for mentioning ocean acidification—25 percent of which will go into the oceans to make the 

oceans 30 percent more acidic within 50 years, and then continuing 

on after that to make it so acidic that it reaches levels since not 

seen since the age of the dinosaurs and dissolve coral reefs. 

Shouldn’t Congress support that? People would say, you are crazy. 

Geoengineering on that scale, which is what we are doing, and now 

we are looking at ways to reverse that. 

Second observation would be, you know, years ago there was a 

psychologist named Elizabeth Ku ̈bler-Ross who looked at what happens when people are dying, and not everybody goes through her 

five stages of dying, which got a lot of play at the time. Nevertheless, her stages of dying went, you know, denial and then bargaining, and the bargaining tends to be, isn’t there going to be 

someone to come rescue me from this cancer or this other illness 

that I have got? 

It strikes me that we are in sort of in those stages now, and the 

reason I raise that, in the context of geoengineering. We have had 

a whole series of hearings in my subcommittee and this full committee on carbon sequestration, on nuclear fusion, on 

geoengineering, and it seems to be everybody is trying to say, isn’t 

there someway out there that we don’t have to make changes in 

our behavior, that we can continue to spew just as much CO2 or 

use just as much energy and something somewhere is going to save 

us from just having to make this horrific changes like turning 

down our thermostat, putting air in our tires, et cetera? And so I 

applaud you all for suggesting that we are not going to have this—

to rescue us by, you know, chemtrails or whatever people want to 

distribute into the air. 

There are some positive things that we could do. What would be 

the impact of simple things like changing the color of roof shingles 

or painting the rooftops? My rooftop here in town is black. It is a 

black rubber surface. It gets hot as blazes up there. I am told we 

can make substantial differences in temperature and energy consumption, not on the scale that we need. It is not enough. But the 

point is, piece together the small stuff that doesn’t require massive 

interventions. What are some of the things we could do? 
85

Dr. ROBOCK. Actually, if we put solar panels on our roofs, that 

would be a much better way to respond because we would produce 

electricity from the sun and that would reduce the amount of CO2

emissions from other sources, and that would be much better than 

just painting the roofs white. It would cost a little bit more money 

to start with, but in the long run, it would be the best investment 

and it would be a business opportunity. Why doesn’t every new 

house have solar panels built into the shingles rather than retrofitting it like I did on my house, thanks to the subsidies from the 

State of New Jersey? 

And there are lots of little things we can do, and they will all 

add up to a mitigation plan. 

Mr. BAIRD. We focused mostly today so far on atmosphere and 

solar radiation management. What about in water? I mean, we are 

also geoengineering our water system. We are putting hundreds of 

billions of pounds of effluent and fertilizers, et cetera, in the water. 

What are some positive changes that we can do to agricultural 

practices, runoff practices, et cetera, that could help improve the 

quality of our water, not, you know, dumping clay as a flocculent 

of algal blooms but some positive things to reduce them from occurring to begin with. Do any of you have comments on that? Are we 

mostly atmospheric today? You get the point I am trying to make 

here, that we are causing the problem through our own behavior 

and then we are somehow going to try to fix the earth instead of 

fixing ourselves. If you had to summarize that, which would you 

say is easier, change our behavior or change the planet? Dr. Shepherd? 

Dr. SHEPHERD. Well, you are making it into a black-and-white 

choice, and my answer would be both. The problem is there is an 

awful lot that we could do in Europe, in the United States and in 

China and everywhere to reduce the impacts that we are having, 

but however hard we try, that may not be enough. So I think it 

is a mistake to make it black and white and say it is either/or. I 

think we need to do both, and that may at some stage involve 

geoengineering. 

Mr. BAIRD. My time is expired. Thank you. 

Chairman GORDON. Thank you, Dr. Baird. Dr. Barlett. Excuse 

me, Dr. Ehlers is recognized. 

Mr. EHLERS. Thank you, Mr. Chairman. I appreciate the interesting interaction you just had. I am not quite sure what Mr. Baird 

meant when he talked about fixing people. I know a lot of people 

fix their dogs and cats, but on the other hand that might be part 

of a good solution. 

Mr. HALL. Professor, do you remember the name of that woman 

that wrote that book? 

THE NEED FOR A MULTIDISCIPLINARY AND REALISTIC

APPROACH TO CLIMATE CHANGE

Mr. EHLERS. Anyway, hearing this discussion I am very much reminded of Garrett Hardin who was a great environmentalist, and 

he had a statement which I framed and hung on my wall for a 

while. You can’t do just one thing. And that is the heart of the 

issue we are facing here today. I think we have a lot of good ideas, 

a lot of things we might want to try, but you can’t do just one 
86

thing. And almost everything you do has side-effects, some may be 

good, some may be bad. Frequently you don’t know until you have 

tried it. And that is what is going to be the major impediment here 

as we proceed. 

There is also a public attitude problem that—well, the best example that I can give you, in the 1973 gas shortages, when we had 

the big long gas lines, and you know, as a physicist I was very interested in people’s attitude toward energy, and I thought we could 

do a much better job of conserving energy. The response of most 

people even talking to me would say, well, we really don’t have to 

worry about this. The scientists will come up with a solution. This 

intrinsic faith that science can solve mammoth problems like that 

is not—it is nice they think that much of me, but I don’t think it 

is realistic. I think we have to face these problems in all of their 

dimensions. 

And the point was made about China and India and what their 

attitude is going to be. As long as we continue with the current economic behavior of this Nation, we have no leverage in which to try 

to solve the environmental problems. How can we threaten the Chinese? If you don’t do this for us, we are going to stop borrowing 

money from you. That is not an awful lot of leverage. 

So I think you have to keep all these factors in mind. I am not 

in the least bit skeptical about geoengineering. I think that is 

something we really have to investigate. I am skeptical about saying this is the answer to a major problem until we get some data, 

do some experiments, find out what works and what doesn’t work, 

and above all, continue to recognize you can’t do just one thing. 

I remember very clearly—I am showing my age by this—but in 

the era when everyone believed we could shoot silver iodide up into 

the atmosphere and make rain wherever we had a drought spot. 

And we seriously pursued this in some areas of our Nation and 

found that it just didn’t work well because we had a lot of side-effects we didn’t anticipate. 

So this was a bit more of a sermon than a question, and you are 

welcome, any of you who wish to, can feel free to comment on this 

and how you think our Nation and other nations can address this 

problem in a thoughtful, reasonable, meaningful way to try to come 

up with some solutions of geoengineering that would work. Any 

comments? Yes. Dr. Caldeira. 

Dr. CALDEIRA. I think you are correct in that we can’t do just one 

thing, and that I think everybody on the panel here believes that 

we need to eventually get to an energy system that does not use 

the atmosphere as a waste dump for our industrial products, but 

that there is a potential for some of these methods to reduce the 

risks that we are facing and reduce these risks cost-effectively. And 

while the panel disagrees about maybe the scale and scope of what 

a research program should be, I think it is indicative that the entire panel asserts the need for a research program. 

I would just also like to take this opportunity to support something Alan Robock said before when I was talking about the structure of research, that on the solar radiation management side, 

there is an environmental science component that might be NSF 

but there is another component about developing and engineering 
87

hardware that might better fit in the agencies that Alan mentioned. Thank you. 

Mr. EHLERS. Dr. Robock? 

Dr. ROBOCK. I would just like to say that we can’t hold 

geoengineering as a solution and allow that to reduce our push toward mitigation. It is never going to be a complete solution. We 

may need it in the event of an emergency, but let us not stop mitigation and wait and see if geoengineering would work. That is not 

the right strategy. 

Mr. EHLERS. Along that line, I think it would be very important 

for us to continue very strongly the approach of reducing our use 

of fossil fuels. For example, I have advocated for years that we try 

to move to solar shingles, that every house has to be built with 

solar shingles. 

Dr. ROBOCK. We don’t really need all these lights on in here, either. 

Mr. EHLERS. No, we don’t. 

Chairman GORDON. Well, the cameras wouldn’t work as well. Dr. 

Ehlers, if you don’t—I am going to be a little more strict because 

we are going to votes, unfortunately, in a few minutes. 

Mr. EHLERS. It is so amazing how the clock runs so much faster 

when it is my time. 

Chairman GORDON. Well, it is also moving up, not down. 

Mr. EHLERS. Thank you. 

Chairman GORDON. Dr. Griffith, you are recognized for five minutes. 

THE CHALLENGE OF INTERNATIONAL COLLABORATION

Mr. GRIFFITH. Thank you, Mr. Chairman. I appreciate this opportunity, and I do think the initial discussions of this subject are important, even though we may not reach a conclusion. We do know 

we have a wide diversity here, with the life expectancy of a male 

in China of 73 and the life expectancy of the male in India of 63, 

which points out a great disparity in what the needs of the various 

countries are. And it makes it greatly difficult for a country like 

the United States that represents only five percent of the world’s 

population to come to a conclusion or reach an agreement on how 

we should approach or sell ourselves to the rest of the world. I 

guess if we included Germany, France and England in that population group, and Denmark, we may get up to six or seven percent 

of the world’s population. 

So it is a good subject, and it is certainly necessary. I appreciate 

each and every one of you being here, and I appreciate the Chairman bringing the subject up. I think this is a start, so thank you. 

Chairman GORDON. Thank you, Dr. Griffith. Dr. Bartlett is not 

here right now. We will recognize him when he gets here, so Mr. 

Smith, you are up to bat. 

AGRICULTURE AND LIVESTOCK

Mr. SMITH OF NEBRASKA. Thank you, Mr. Chairman. I will try 

to be brief. This is my third year here, and it is interesting being 

on the Science Committee and trying to sift through the science 

and, you know, whether something is peer reviewed, whether it is 
88

not, and rejection of recommendations that are science is peer reviewed. It has been for this Nebraskan interesting and how we 

might contribute and especially as it relates to industry in my district. And if any of you could speak to the impact, your perceived 

impact, of livestock industry, I have heard various accusations, and 

if any of you would care to comment on that. 

Dr. CALDEIRA. I am not expert on the livestock industry, but I 

do know that one of the concerns with respect to livestock and global warming are methane emissions from livestock. And I know that 

people are working on various ways of removing methane from 

gases that might be in barns or pens where livestock are held, and 

it might be potential for the kind of research to remove greenhouse 

gases from the atmosphere in general also to be applied to facilities 

such as livestock pens or barns. 

Mr. SMITH OF NEBRASKA. Thank you. Anyone else? 

Dr. FLEMING. Yes, I am involved with the University of Kansas 

in a group that is doing this interdisciplinary graduate education, 

and certainly as one of your neighbors, the group there is getting 

technical training in agricultural sciences as well as in techniques 

to mitigate or perhaps reduce some of this. But the group is also 

looking at behavioral issues and choices and ways of working together with the industries to advance their purposes as well as 

other goals. 

And so the point I was making is that I think the education we 

have often is in content and technique of science or techniques of 

engineering, but that social dimension is very important. And so in 

looking at issues like global warming, making personal commitments and personal decisions I think is a very significant aspect of 

this program. It is not a solution to the beef issue, but if smoking 

is bad for you or beef is bad for the planet, people have to make 

some decisions or alignments. 

Mr. SMITH OF NEBRASKA. Are you suggesting that beef is bad for 

the planet? 

Dr. FLEMING. No, but others have. It has been in the news recently. 

Mr. SMITH OF NEBRASKA. Well, I did read the comments of a 

writer one time who said that eating a T-bone steak is more egregious to the environment than driving a Hummer per se. I was astounded, you know. I am not sure the nutritional values were considered, you know, in the bigger picture, but certainly there are 

some concerns, especially in the midst of this economy, that in the 

so-called mitigating efforts, whether it is cap and trade, which is 

called a lot of other things, or whatever approach we might take, 

I hope that we remember that we need to look at the big picture 

economically, that there are some important factors here. Dr. 

Caldeira? 

Dr. CALDEIRA. We do not know how well these methods will 

work, these solar radiation methods will work at affecting regional 

climates, but there is at least some possibility that as a result of 

climate change, weather conditions will change in America’s heartland and that this will impact on the production of grain. And you 

know, I would be misleading you if I said oh, I thought we could 

reverse this, but I think there is at least the potential that a research program with a relatively small investment could under-
89

stand, you know, if the American heartland does turn into a 

dustbowl, is there a potential to change weather patterns to allow 

us to engage in agriculture once again? And so even if there is a 

small probability that this will occur, the investment is small and 

so the expected benefit of this investment is very high. 

Mr. SMITH OF NEBRASKA. In my part of the country that I represent we had an extended drought, and now we have certainly a 

wet October. Is that wet October a result of climate change and 

carbon emissions? 

Dr. ROBOCK. There is a lot of weather variability that, because 

of the chaotic nature of the weather, you can’t attribute any 

drought or any flooding event to global warming. The probability 

of different weather events changes over time, but certainly that is 

just part of normal weather variability. 

But cows do put a burden on the climate system. There are the 

methane emissions and there is all the energy used in the production of beef, and so that is—one of the mitigation strategies is for 

people to eat less beef. And maybe there could be a way for your 

constituents to gradually transition to other things that they could 

do that would create less greenhouse gases. 

Chairman GORDON. I am sure that is the answer you wanted to 

hear, Mr. Smith. 

Mr. SMITH OF NEBRASKA. If only my time had not expired. Thank 

you, Mr. Chairman. 

Chairman GORDON. Ms. Kosmas is recognized. 

THE POWER OF SCIENTIFIC INNOVATION

Ms. KOSMAS. Thank you, Mr. Chairman. I appreciate the opportunity to listen to these gentleman before us today and to suggest 

to all of you here—I am from Florida, and Kennedy Space Center 

is in my district, and so I am really big on solar and sun as well 

as NASA and space exploration. So my remarks will be focused for 

the most part on the solar radiation management, my remarks and 

questions. But I want to suggest to my friend, Mr. Hall, that while 

you might think this is science fiction, I was talking with my 

daughter yesterday who was telling me my son, who is in China, 

was saying that they had a massive snowstorm induced by the 

state of China or the nation of China. So do you not believe that 

that happened? 

Dr. ROBOCK. I believe that the snowstorm happened, but I don’t 

think you can prove that they caused it. 

Ms. KOSMAS. Okay. All right. Well, maybe it is science fiction. I 

don’t know. But it is interesting, and I suspect if they could, they 

would. And so I think all the comments mentioned today about the 

necessity for research and development and international cooperation in so doing are valid and worth great consideration, that it is 

not impossible and maybe not even improbable that someone, 

somewhere will ultimately take advantage of the scientific opportunity. I would like to see us move forward with research and development, and I appreciate the comment of Dr. Shepherd that, you 

know, be careful what you ask for because you are going to have 

to wind it down eventually. And as you suggested with the volcanoes, you need to know where you are going next. 
90

Nevertheless, I think in this Nation we have both the brains and 

the capability to move forward on new frontiers as this is, mitigation, obviously, combined with new opportunities for better ways to 

produce energy and also to protect the environment. They kind of 

seem like they go without saying. 

In fact, one of the reasons that I ran for office is exactly that. 

I think we needed to be moving in a different direction in this 

country with regard to protection of the environment and conservation of energy and new energy methodology. So I am pleased to be 

here and pleased to be on this Committee. 

GEOENGINEERING AND CLIMATE SIMULATIONS

I wanted to just discuss for a moment with Dr. Caldeira, you discussed in your comments the simulations and small-scale field experiments of solar radiation management. Can you discuss what 

the simulations and the experiments entailed? Let us start with 

that. 

Dr. CALDEIRA. Today there have been a number of modeling 

groups using climate models to simulate the effects of deflecting 

more sunlight away from the earth, and I believe that all of the 

simulations that used some reasonable amount of sunlight deflection found that sunlight deflection was able to reduce most of the 

climate change in most places most of the time. But as Alan 

Robock points out, after Mount Pinatubo, the Amazon and the Ganges River delta had some of the lowest river flow on record. And 

so there are negative consequences we need to be aware of and to 

study more deeply. 

In terms of experiments, so far no experiments have gone on in 

the field, but we could think of process-based experiments. You 

know, if you did put some material into the stratosphere, what 

kind of chemical reactions would occur? Would the particles stick 

together? So there are a lot of small-scale field studies that could 

be done short of something that affects climate. And we need to 

think carefully about how to go about conducting these experiments. 

A POTENTIAL ROLE FOR NASA 

Ms. KOSMAS. Okay. I know that it has been suggested that the 

National Science Foundation and DARPA, maybe, would be agencies. Could you tell me something about your feeling about NASA 

being involved perhaps in these projects? Yes, sir. I am sorry. 

Dr. ROBOCK. We use a NASA climate model with NASA computers to do our simulations, and certainly NASA should be heavily 

involved in the climate research. And also, NASA puts up satellites, and we need a capability being able to measure particles in 

the stratosphere. There used to be the SAGE satellite, stratospheric aerosol and gas experiment, but they no longer exist. There 

is a spare sitting on a shelf in Hampton, Virginia. 

Ms. KOSMAS. We could bring it down to the Kennedy Space Center, and I guarantee you we could get it out there. 

Dr. ROBOCK. That is right. And so NASA really needs to be involved in an enhanced earth-observing program that can really 

help us. I was here in Washington earlier this year at the National 
91

Academy of Sciences in a panel, are we ready for the next volcanic 

eruption? And the answer was no. And Jim Hansen was sitting 

next to me. He said, no, we need a better capability of being able 

to observe the stratosphere for a volcanic eruption and for any 

geoengineering experiments. And NASA could be heavily involved 

in that. 

Chairman GORDON. Thank you, Ms. Kosmas. I think you are 

going to get some business down there. 

Ms. KOSMAS. Good. Thank you. 

Chairman GORDON. Mr. Rohrabacher, Mr. Hall has been anxious 

by awaiting your five minutes. 

Mr. ROHRABACHER. Thank you very much, Mr. Chairman, and no 

hearing like this would be fulfilled without my adding a list at this 

point of 100 top scientists from around the world who are very 

skeptical of the very fact that global warming exists at all, but I 

would like to submit that for the record at this time. 

[The information follows:]
92
93
94
95

SKEPTICISM OF GLOBAL CLIMATE CHANGE

Mr. ROHRABACHER. There you go. Let me just note that there is 

ample reason for us to question whether or not things that are 

being suggested today are really needed because there is reason to 

question whether there is global warming, considering the fact that 
96

it has gotten—it is not gotten warmer for the last nine years, and 

the Arctic polar cap is now refreezing for the last two years. 

But that argument isn’t what today’s hearing is about, so I will 

just make sure that that is on the record and in people’s minds 

when looking at some of these suggestions. 

Let me ask about some of the specific suggestions. I understand 

at 9/11 when they grounded all the airplanes that it actually increased the temperature of the planet, is that right? And thus——

Dr. ROBOCK. Excuse me, that is not correct. 

Mr. ROHRABACHER. It is not correct? 

Dr. ROBOCK. There was one study that showed that without 

clouds from contrails that the diurnal cycle of temperature went 

up, the daily temperature went up, the nighttime temperature 

went down, but later disproven. It was shown that was just part 

of natural weather variabilities. So that wasn’t a very——

Mr. ROHRABACHER. Let me note that every time it doesn’t fit into 

the global warming theory, it becomes natural variability but when 

it does fit in, it becomes proof that there is global warming. 

Let me ask you this. That really wasn’t then? Does anyone else 

have another opinion of vapor trails, by the way? So we have 

learned today that we really just have—and am I misreading you 

by suggesting that you, too, are part of the group that believes in 

global warming that would like to restrict air travel or try to find 

ways of eliminating frequent flyer miles? We know you don’t want 

us to eat steak now. Are we also not going to be able to fly on airplanes? 

Dr. ROBOCK. Airplanes are one of the sources of emissions. If 

they use biodiesel and it recycles the fuel, then it wouldn’t be part 

of the problem. But indeed, if we—we can do some emissions of 

CO2. We don’t have to—these mobile transportation sources are 

very hard to retrofit on airplanes. With cars, you can, of course, 

generate electricity with wind and solar, but airplanes, we still 

have to keep flying and we can live with a little bit of CO2 emission 

if we deal with other sources. 

Mr. ROHRABACHER. Again, let me note that—by the way, you are 

a scientist here. What is the percentage of the atmosphere that is 

CO2? What percentage of the atmosphere? 

Dr. ROBOCK. It is .039 percent. 

Mr. ROHRABACHER. Okay. And most people, when I ask that 

question, Mr. Chairman, out in the hinterland, people believe it is 

25 percent, and instead of this miniscule, that is .03, that is 3 percent of 1 percent of the atmosphere. And there are those who have 

realized—in the past there have been many times when that CO2

content was enormously greater, wasn’t that right? And during 

that time period there were lots of animals, like dinosaurs and lots 

of things growing, and the world seemed to be doing pretty good. 

Dr. CALDEIRA. CO2 concentrations were high in the past, and the 

biosphere flourished. And even if we disagree about what the 

threats are from climate change, and I think we do, that, you 

know, I don’t think my house is going to burn down, but I buy fire 

insurance. And——

Mr. ROHRABACHER. But you don’t tell your neighbor that he can’t 

have steak or visit his kids in an airliner, and that is the point. 

Dr. CALDEIRA. I don’t——
97

Mr. ROHRABACHER. There are going to be changes. People have 

to understand, there are going to be huge changes in our lifestyle——

Dr. CALDEIRA. I don’t——

Mr. ROHRABACHER.—if this nonsense is accepted. 

Dr. CALDEIRA. I don’t believe we are going to solve this problem 

by asking people to behave differently. 

Mr. ROHRABACHER. Okay. 

Dr. CALDEIRA. I think we are going to solve it by improving the 

systems that surround us. But to get back to my point, even if we 

don’t believe that climate change will damage us, we have to say 

there is some risk. So then we have to say, well, how much should 

we invest to try to mitigate that risk. 

Mr. ROHRABACHER. We are broke right now, and the bottom line 

is that we have very little to invest in theories that may or may 

not be correct, and we also have a lot of indication, just the fact 

that you are using the word climate change is a difference than 

what was used 10 years ago which was global warming. And most 

of us realize that is because people now are trying to hedge their 

bets so they can have these controls, whatever way the temperature goes. 

Dr. CALDEIRA. No, I don’t think that is true. You know——

Chairman GORDON. Time. 

Mr. ROHRABACHER. Thank you very much. 

Chairman GORDON. Speaking of dinosaurs, the time for Mr. 

Rohrabacher has run out, and we will need to proceed to——

Mr. ROHRABACHER. Thank you, Mr. Chairman. 

Chairman GORDON. Mrs. Dahlkemper. 

PRIORITIZING GEOENGINEERING STRATEGIES

Mrs. DAHLKEMPER. Thank you very much, Mr. Chairman, and I 

want to thank our witnesses for coming today. This is a fascinating 

hearing, and I look forward to more hearings on this as we delve 

into this subject further. 

I have a question for the panel and anyone who would like to address it. Do you believe that any particular geoengineering options 

should be removed from consideration completely? If so, why? 

Dr. CALDEIRA. You know, I think we have to think in terms of 

a portfolio and that there are some things that are clearly more 

promising. There are some things that can be scaled up on the 

solar radiation management side. There are things that could be 

scaled up and deployed rapidly, and I think those two are really 

particles in the stratosphere and perhaps whitening clouds over the 

ocean. 

On the carbon dioxide removal side, there are a bunch of landbased options to increase the storage from carbon from photosynthesis that need to be explored, and also industrialized capture of 

CO2 from the air, and also spreading minerals around on the earth. 

My own view is that other options such as ocean fertilization, for 

example, are not going to play a significant role in solving the problem. That is not to say I would put zero money into them. I would 

just put them way down in the list of my portfolio of investments. 

Mrs. DAHLKEMPER. Anyone? Dr. Robock? 
98

Dr. ROBOCK. There has been a suggestion to put frisbees into 

space to put a cloud of particles, of satellites, up to block the sun 

at a point between the earth and the sun, and that would probably 

cost trillions of dollars and nobody is sure if it would work. So I 

wouldn’t suggest we invest money in that idea. 

Ms. DAHLKEMPER. Dr. Shepherd? 

Mr. SHEPHERD. I would personally exclude from consideration 

the idea of covering desert areas with reflective material because 

of the potential impacts on local rainfall patterns, not to mention 

the environmental impacts on the desert ecosystems themselves. 

Ms. DAHLKEMPER. Dr. Fleming? 

Dr. FLEMING. Given the hurricane I showed that came ashore, I 

would also suggest we be very careful about redirecting storms. 

Mrs. DAHLKEMPER. Dr. Caldeira. 

Dr. CALDEIRA. I think we need to be clear what kind of research 

we are considering. If we are talking about a climate model and 

somebody wants to say, well, what would happen if we changed the 

reflectivity of a desert in a climate model, that is a small-scale, 

non-invasive kind of research that might be good to do. But if 

somebody wants to start rolling out giant plastic sheets over the 

deserts, that is something that we shouldn’t do. So what I am talking about portfolio, there are some things that we should do at 

small scale, maybe just in climate models and that should receive 

relatively low priority. 

Dr. ROBOCK. And I would say there is nothing that we should do 

right now. We need a lot more research, theoretical research, with 

climate models to see what the benefits but also the risks would 

be of different suggested strategies. So far everybody has done a 

different climate model experiment. It is hard to compare the results. So I am organizing an international program where all the 

climate modeling groups in the world do exactly the same experiment so we can see, do they really get drought in certain regions 

for certain experiments. And if everybody does the same experiment, we can compare it, and we will have a much better confidence that our models are correct, just like we do for global 

warming experiments. 

NEEDED INTERNATIONAL AGREEMENTS

Mrs. DAHLKEMPER. If we are looking at this climate system being 

so complex, and we haven’t even talked about some of the international agreements, what kinds of things do we need to have in 

place in terms of international agreements and legal steps before 

we could really do a large-scale testing initiative? Mr. Lane? 

Mr. LANE. Yes, I would pick up on something that I said in my 

written statement which is that nations may differ in their interests in geoengineering, at least in solar radiation management, 

which is the kind we are talking about for the most part here. I 

would suggest that the United States really needs to learn a lot 

more about the potential risks and benefits of solar radiation management for the United States before it embarks on any kind of 

international agreement or international protocol. We need to be 

clear on U.S. interests, not that it ultimately isn’t going to turn 

into international bargaining, but each country needs to be clear 
99

about its own interests before we are ready for diplomatic bargaining, I would suggest. 

Chairman GORDON. Thank you, Mr. Lane. 

Mrs. DAHLKEMPER. Thank you. 

Chairman GORDON. To demonstrate that the California Republican Party is a big tent, Mr. Bilbray is recognized. 

Mr. BILBRAY. Thank you, Mr. Chairman. I would like to quickly 

yield to the gentleman from the frozen wasteland of Nebraska at 

this time. 

MORE ON LIVESTOCK METHANE OUTPUT

Mr. SMITH OF NEBRASKA. I didn’t realize that was a—thank you, 

I guess. 

Dr. Robock, following up on your suggestion that mitigating the 

consumption of beef would help the environment, do you see any 

nutritional drawbacks to that? Do you consume beef yourself? 

Dr. ROBOCK. Yes. Now, I am not an expert on nutrition or on the 

entire system of agriculture. I have just seen papers that calculate 

how much greenhouse gases are admitted for, say, a pound of beef 

versus a pound of pork or a pound of chicken or a pound of potatoes, and just in that one narrow way of looking at it, there is more 

emitted that causes more global warming from beef. 

Mr. SMITH OF NEBRASKA. But a narrow way of looking at it, you 

are suggesting? 

Dr. ROBOCK. Yes. Yes. There are a lot of other considerations. I 

am just talking about the impact on global warming. 

Mr. SMITH OF NEBRASKA. But you would advocate mitigating consumption of beef as a means of accomplishing your objective? 

Dr. ROBOCK. Yes. 

Mr. SMITH OF NEBRASKA. And how would you suggest going 

about that? And in the interest of time, I do want to leave some 

time. How would you suggest going about that? 

Dr. ROBOCK. Education. I mean, people—you can’t—I don’t—it is 

your job to decide what to tax or not to tax. Obviously, if you wanted people to behave differently, you give them incentives and disincentives for behavior. But that is just one of the ways that the 

climate system responds to methane and it responds to carbon dioxide, and the current way of producing beef emits a lot of those 

gases. That is just—what to do about it? What the entire portfolio 

of mitigation should be? I am not——

Mr. SMITH OF NEBRASKA. However, you just advocated for something to mitigate the consumption of beef? 

Dr. ROBOCK. Well, so the way—if you do want to do that, of 

course, then you give——

Mr. SMITH OF NEBRASKA. For the record, I don’t want to. 

Dr. ROBOCK. I mean, I guess I am trying not to say something 

that will make you feel bad but I am trying also to be honest 

about——

Mr. SMITH OF NEBRASKA. I think you are a little too late. 

Dr. ROBOCK. Sorry. 

Mr. SMITH OF NEBRASKA. But thank you. 
100

THE NEED FOR MITIGATION

Mr. BILBRAY. Reclaiming my time, Mr. Chairman, as stated before, the changing, you know, quote unquote, lifestyles or whatever 

is going to be too little, too late. I want to thank you for having 

this hearing. The fact is after seeing what kind of proposal that 

supposedly was going to address climate change that came out of 

the political structure here, I have come to the conclusion that we 

need to talk about mitigation of the crisis because we are not going 

to avoid it. There is not the political will to do what it takes. There 

is not even the political will to make it legal in the United States 

to do what it takes to avoid climate change because I believe 

strongly that we have got to have the ability to produce energy that 

doesn’t emit greenhouse gases so we can shut down all those facilities that do, and there is not the political will to do with that what 

we did with the interstate freeway system where the government 

went out and sited, did the planning, did the things so we can shut 

down the coal producing and the emissions and all that other stuff. 

We are not willing to do that. We are just willing to talk about how 

terrible it is. 

GLOBAL DIMMING AND RISKS OF STRATOSPHERIC

INJECTIONS

So this is going to be a treating the crisis and trying to mitigate 

the adverse impact, and I appreciate that approach. The question 

is, there was a comment, have we now eliminated global dimming 

as a consideration in this issue? 

Dr. ROBOCK. If by global dimming you mean the effect of——

Mr. BILBRAY. The pooling effect of particulates——

Dr. ROBOCK. In the troposphere. That is not global but it is continuing in places that emit a lot of particles, like in India and 

China. But solar radiation management is global dimming on a 

global scale. People are talking about putting a cloud in the stratosphere, not down near here where we breathe it. 

Mr. BILBRAY. My concern is as somebody who has worked on air 

pollution, I would assume eliminating coal—I mean, clean coal is 

like safe cigarettes. I am hard-core against it, but that is fine. But 

if you eliminate coal which puts a lot of particulates in, I am concerned that there may be an adverse impact we don’t consider. 

Dr. CALDEIRA. If we eliminated coal use today, the earth would 

probably heat up by about another degree Fahrenheit from removing the sulfur. If we put just a few percent of that sulfur in the 

stratosphere, we would get the same cooling effect on a global average while eliminating something like 95 or more percent of lowerlevel pollution. And so we need to think about what if China were 

to say, for each power plant that we put sulfur scrubbers on, we 

will take three or four percent of that sulfur and put it higher in 

the atmosphere to get that cooling effect while eliminating 95 or 

more percent of the——

Chairman GORDON. Excuse me, Doctor. We have about eight 

minutes until we have to go vote. So I just want to assure Mr. 

Smith that he can go home and tell his constituents that the beef 

police will not be knocking on their door. And I recognize Mr. 

Luja ́n to conclude our questions. 
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THE IMPACT OF INGENUITY AND BEHAVIOR CHANGE

Mr. LUJA ́ N. Mr. Chairman, I appreciate that, and as someone 

that enjoys a T-bone or a lamb chop, sometimes it is raised on the 

family farm that I live on. And I hope to do more wonderful hunting in New Mexico. I would invite my colleagues to come down to 

New Mexico to see for themselves. I appreciate the emphasis with 

mitigation and what we are talking about here. I would say that 

as we look to see what we have to do as a Nation and what I hope 

that we are truly looking at here is not telling people they don’t 

have to fly to visit their family or that they don’t have to eat beef 

or that they don’t have to do whatever it is that is being said today, 

but that we are telling people we can be smarter about the way 

that we do things—that we are saying when we are talking about 

human behavior, I do not see how encouraging people to be more 

efficient with their home energy use or with vehicle use or being 

smarter about things like that, that that doesn’t have a positive 

impact on all that we are looking at. 

Again, being smarter about the way we do things, being able to 

embrace ingenuity and challenge our scientists, our engineers, our 

researchers to continue to do great things. You know, when I was 

young I remember watching cartoons about science fiction and this 

whole notion that people could one day be in space, building a 

space station, not only walking on the moon but staying up there 

for months upon end to do research. Lo and behold, yesterday there 

were three astronauts that came to visit us here on Capitol Hill 

who came back from making improvements where there are more 

and more people that are living in space, staying there for months 

upon end, where in a global community we’re doing some of these 

things that were once considered science fiction. We are being 

smarter about the way we do things, and we are doing them better. 

And so as we look to see what is happening around the earth, 

I know that there are many who truly believe that there still isn’t 

a problem, that this isn’t something that we have to do something 

about. And I would hope that we could get something submitted 

into the record from those of you that are willing to speak to them, 

to tell us what it is that we can share with them as well, to talk 

about this problem that I believe is facing us as a Nation and facing us as a global community. 

CLIMATE MODELING RESOURCES

As we talk about the science, though, and what indeed that we 

can employ to be more aware of what is actually occurring with the 

warming of the oceans or weather patterns, can you talk about the 

importance of how we are able to include computer modeling capabilities, of research laboratories, of our national laboratories, of our 

colleges and our universities around the United States that have 

super-computing capabilities and the ability to now use new data 

to be able to feed you the information that you need so that we can 

indeed solve some of these problems? Dr. Caldeira? 

Dr. CALDEIRA. I and my colleagues did some of the first computer 

model simulations of the solar radiation management methods at 

a Department of Energy National Lab, Lawrence Livermore Lab, 

and the kind of computing facilities at places like Los Alamos and 
102

the other labs in the system are really valuable and were a great 

place to be able to do this work. 

I am also, as an academic, a strong supporter of our academic research institutions and the computing facilities at those institutions. And I think that there is potential through investing in this 

research area to revitalize our science, education and the computing facilities that support that education. 

Chairman GORDON. Dr. Caldeira and for the rest of the panel, we 

are down to less than five minutes now, so I will quote, if he 

doesn’t mind, Dr. Ehlers in saying, Mr. Luja ́n, you brought us to 

an eloquent conclusion. Thank you for your statement. 

Before we close the hearing, as I told the witnesses earlier, I will 

provide for them two questions, one, what does a research program 

look like, and the second one, if we have any type of international 

treaties or collaboration, what should that look at. We would also 

welcome any comments to follow up, Mr. Luja ́n, or anything else. 

You have been an excellent panel. This has been I think an important hearing, the start of a longer-term discussion, and I think 

that we can say with consensus that no one is advocating that 

geoengineering is a one-stop shop or any type of an alternative to 

mitigation, but is something that needs to be reviewed. And so I 

will say now that the record will remain open for two weeks for additional statements from Members and for answers to any followup questions the Committee might ask the witnesses. The witnesses are excused, and the hearing is adjourned. Thank you. 

[Whereupon, at 11:45 a.m., the Committee was adjourned.] 
(103)

Appendix: 

ANSWERS TO POST-HEARING QUESTIONS
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ANSWERS TO POST-HEARING QUESTIONS

Responses by Ken Caldeira, Professor of Environmental Science, Department of Global Ecology, The Carnegie Institution of Washington, and Co-Author, Royal Society Report

Questions submitted by Representative Ralph M. Hall

Q1. For the Solar Radiation Management options, you state that there are only two 

that would be able to address a significant part if not all warming issues, sulfate injections and cloud seeding.

a. Although smaller options like white roofs and surfaces or desert reflectors 

would not address the whole warming issue, would it be useful to deploy these 

low impact options?

b. Or, is the idea that once the radiation infiltrates the earth’s atmosphere to a 

point where it would be reflected off the surface, the battle has already been 

lost since it will be captured on its return to space?

A1. Dr. Caldeira did not provide an answer to this question.

Q2. In your testimony you mention the Mt. Pinatubo volcanic eruption in 1991 that 

caused a 1 degree Fahrenheit cooling of the earth for about a year or two. Then 

the particles in the stratosphere discharged by the volcano left, and the cooling 

effect wore off.

a. Where did those particles go to?

b. Is there a similar concern about acid rain or particulate matter pollution if 

we inject particles into the stratosphere to simulate a volcanic eruption?

A2. Dr. Caldeira did not provide an answer to this question.

Q3. Ultimately, almost all the energy we use here on earth comes from the sun. Coal, 

oil and natural gas are essentially the remainder of large amounts of biomass 

from millions of years ago. Water, wind, and to a lesser extent, tidal energy are 

all derived from the Earth-Sun system. Solar and bioenergy quite obviously require energy from the sun. Only nuclear and geothermal energy seem to be independent of energy from the sun. What are the potential risks to global energy 

resources if we reduce the amount of solar radiation reaching the Earth?

A3. Dr. Caldeira did not provide an answer to this question.

Questions submitted by Representative Dana Rohrabacher

Q1. If stopping coal use immediately would cause more supposed warming than the 

entire CO2 increase since the beginning of industrialization, why is that a good 

thing?

A1. Dr. Caldeira did not provide an answer to this question.
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ANSWERS TO POST-HEARING QUESTIONS

Responses by John Shepherd, FRS, Professional Research Fellow in Earth System 

Science, National Oceanography Centre, University of Southampton, and Chair, 

Royal Society Geoengineering Report Working Group

Questions submitted by Chairman Bart Gordon

Q1. Please describe what you think a comprehensive federal research program on 

geoengineering should entail. What are the critical features of such a program?

• Which U.S. agencies would contribute to a research initiative, and in what capacity?

• What scale of investment would be necessary, both initially and in the longer 

term?

• What kind of professional and academic expertise would be required?

A1. A comprehensive research programme should involve research on both Solar 

Radiation Management (SRM) and Carbon Dioxide Removal (CDR) methods, since 

CDR methods are less risky, and would be needed for a long-term solution, to provide the exit strategy for SRM methods, and to deal with the ocean acidification 

problem. Since it is too early to pick winners, research on several of the more promising methods of each class should be undertaken. The scientific and technological 

research should comprise technological development, computer modelling of both intended and unintended environmental impacts, laboratory and pilot-plant scale experiments, and field testing on various scales in due course. For methods which involve dispersion of material in the environment and/or transboundary effects (other 

than simply the removal of greenhouse gases (GHGs) from the atmosphere), largescale field tests should await the establishment of appropriate national and/or international arrangements for the regulation of such research. Research on economic aspects (especially life-cycle assessment on financial, energy and carbon accounting 

bases), and on social, legal, ethical and political aspects should be undertaken in 

parallel. 

I am not an expert on U.S. research funding or institutional capability, but would 

advocate that the research should be undertaken as a coordinated joint programme 

by academic institutions, national laboratories and where appropriate also by contracted commercial research organisations. Funding of various aspects by NSF, 

DOE, NOAA and NASA would be appropriate. Private and philanthropic funding 

should not be excluded if channelled via a suitably transparent ‘‘arms length’’ mechanism. 

A suitable scale of investment for the U.S.A. would be of the order of $100 million 

per year (direct costs only) for the first five years, as a contribution to a coordinated 

international programme, increasing progressively thereafter (possibly doubling 

each five years) until one or more methods are selected for deployment, or all are 

abandoned as unnecessary or undesirable. 

A very wide range of scientific and engineering expertise will be required (the precise requirement will depend on the technology in question), together with professional expertise in socio-economic and legal fields. Particular areas which may require additional support are in all aspects of Earth System & Environmental 

Sciences, and Chemical, Electrical & Mechanical Engineering. The further enhancement of Earth System Models (and the computing infrastructure to run them) are 

likely to be an early requirement.

Q2. Please prioritize the geoengineering strategies you believe warrant extensive research, and explain your reasoning.

• Within these, please highlight examples of potential negative impacts you predict might accompany their deployment and/or large-scale research.

• Are there any strategies that you believe should be eliminated from consideration due to unacceptable risks and costs?

A2. Estimates of costs for all methods are very uncertain at present, so cost should 

not be taken as a decisive selection criterion for the time being (and it is premature 

to attempt comparative cost-benefit analyses except at a very broad-brush level). 

Among SRM methods the order of priority, nature of the research, and potential 

negative impacts should be 

High: Stratospheric aerosols [R&D on all aspects especially deployment technology, and intended and unintended environmental impacts: possible negative impacts on stratospheric ozone, upper tropospheric clouds, poor cancellation of precipitation pattern changes]. 
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Medium: Cloud brightening [R&D on all aspects especially deployment technology, 

radiative forcing attainable, and intended and unintended environmental impacts: 

possible negative impacts on regional weather patterns & ocean upwelling due to 

strongly localised radiative forcing]. 

Low: Space-based methods [R&D: Desk-based feasibility studies only: potential 

negative impacts due to non-uniform forcing and release of rocket fuel combustion 

products etc to the atmosphere]. 

Among CDR methods the order of priority, nature of the research, and potential 

negative impacts should be 

High: Engineered capture of CO2 from ambient air [R&D on technological development especially energy use and cost reduction: potential negative impacts due to 

materials used and CO2 sequestration] 

Medium: Enhanced weathering methods (both terrestrial and oceanic) [R&D on 

technological development, effectiveness, and environmental impacts: potential negative impacts due to materials & energy used, and possibly on soil and ocean ecosystems] 

Low: Biological methods (SECS, Biochar, enhanced soil carbon & afforestation). 

[R&D on ecological impacts and land-use requirements & conflicts: potential negative impacts on forest & grassland ecosystems] 

Unpromising methods include land-surface (desert) albedo enhancement, and 

ocean fertilisation (by both iron and macronutrients) because of their expected high 

impacts on natural ecosystems. 

[Please see Royal Society report for further explanation of rationale]

Q3. Could some geoengineering activities be confined to specific geographic locations?

• For example, could solar radiation management be localized specifically for 

the protection of polar ice?

A3. In general CDR methods can be applied at any location (e.g. where energy and 

other costs are low) as convenient, though not all would necessarily be confined 

within national boundaries (e.g. ocean fertilisation). 

It would on the other hand be generally undesirable to attempt to localise SRM 

methods, because any localised radiative forcing would need to be proportionally 

larger to achieve the same global effect, and this is likely to induce modifications 

to normal spatial patterns of weather systems including winds, clouds, precipitation 

and ocean currents & upwelling patterns. It would be particularly undesirable to attempt to cool some area (e.g. the polar regions) of one hemisphere but not the other, 

as this is very likely to lead to a shift in the location and seasonal range of the 

inter-tropical convergence zone (ITCZ) with possible alteration of low-latitude 

weather systems (especially the seasonal pattern and strength of monsoon systems). 

It could however be useful to engineer a slight and smooth latitudinal variation 

of SRM forcing {e.g. by aerosol release primarily at high latitudes), to balance the 

spatial pattern of greenhouse warming more precisely, and so to reduce any residual 

over-compensation effects which are likely with a spatially uniform forcing (such as 

a simple fractional reduction of solar radiation).

Q4. In his submitted testimony, Dr. Robock explained simply: ‘‘To actually implement geoengineering, it needs to be demonstrated that the benefits of 

geoengineering outweigh the risks.’’

• What do you believe are the ‘‘tipping points’’ that would justify large scale deployment of geoengineering?

• Based on the current pace of carbon increases (about 2 parts per million a 

year) and your prediction of the efficacy of conventional mitigation strategies, 

what would be an appropriate timeline for research and possible deployment?

A4. I do not consider that a ‘‘tipping point’’ or ‘‘emergency’’ rationale for implementation of geoengineering is appropriate, simply because it will be extremely difficult 

to detect tipping points (at which irreversible state changes occur) before they are 

passed, or even to be certain when they have been passed. Moreover, waiting for 

an emergency situation more or less implies introducing a high level of intervention 

rapidly, which is likely to be imprudent. I think it is more constructive to consider 

trigger or threshold levels at which it would be prudent to commence progressive 

implementation of geoengineering over several decades (allowing the intervention to 

commence at a low level so that one could verify its intended impacts and hopefully 

detect any adverse impacts before they become serious). It could for example be appropriate to commence geoengineering intervention in time and in such a way as 

to limit the increase of global temperature to 2° C (or any other agreed level) and 

maintain it at that level for some considerable time, before deciding whether to seek 
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to reduce it. As stated above and in the Royal Society report, it would be imprudent 

to commence SRM intervention without an exit strategy, such as simultaneously 

commencing CDR intervention on a scale sufficient to supplant the SRM intervention in the long term. 

In the light of current (i.e. post-Copenhagen) expectations of climate change, it 

would be desirable to commence a substantial programme of R&D immediately, 

with a view to possible large-scale deployment in about 20 years time, i.e. about 20 

years before it is expected that the global mean temperature increase will reach 2° C.

Q5. The effects of many geoengineering strategies such as stratospheric injections 

could not likely be tested at less than full-scale. To your knowledge, what types 

of international agreements would address the challenges of large-scale testing?

• Can you identify any existing treaties or agreements that would apply to largescale testing of geoengineering?

A5. To the best of my knowledge, there are no international treaties or institutions 

which are at present appropriate to deal with regulation of geoengineering in general, or stratospheric aerosol release in particular (see fuller discussion in the Royal 

Society report). A major revision and extension of ENMOD, and the creation of an 

executive arm for this treaty, could be a possible route for the future. However, any 

such body would have to cooperate closely with the UNFCCC eventually, to ensure 

coordinated development of mitigation, adaptation and geoengineering activities, 

and such a formal linkage should be created in any new legal and institutional 

framework. A critical review of existing treaties and institutions is a necessary and 

important early action.

Questions submitted by Representative Ralph M. Hall

Q1. Mr. Shepherd, in your written testimony you mention that the technologies required to achieve sufficient mitigation action are available and affordable right 

now.

a. Would you please comment on what those technologies are?

b. Would you consider carbon capture and sequestration technologies available 

and affordable?

c. Would you consider the installation and use of such technologies available 

and affordable?

A1. (a) Please see the report of the Royal Society ‘‘Towards a Low Carbon Energy 

Future’’ (available at http://royalsociety.org/WorkArea/DownloadAsset.aspx?id

=5453) which summarises technologies available for implementation in the immediate future, the medium term (up to 2050) and thereafter. Most such technologies 

would result in somewhat higher energy prices, but should nevertheless be regarded 

as affordable, since energy prices are rarely the dominant component of domestic 

or industrial costs. Moreover energy prices have historically been held at artificially 

low levels (because the costs of the environmental impacts have hitherto been ignored). Society and industry will of course need time to adapt to higher energy 

prices. 

(b) Given a sufficient investment of effort CCS would be available for deployment 

over the next few decades, beginning well before 2020. It would result in a substantial increase in electricity prices, but for the reasons given above this should not be 

regarded as an insurmountable obstacle. 

(c) There are a number of technologies (see above) available for rapid development 

and progressively increasing deployment, but the timescale for the transition to a 

low-carbon energy system is nevertheless several decades even using existing technology such as nuclear fission.

Q2. We’ve heard a great deal today about Solar Radiation Management techniques. 

Would you please tell us of some of the significant side effects and risks associated with stratospheric aerosol methods?

A2. Please refer to the Royal Society report ‘‘Geoengineering the Climate’’ for a detailed account of the possible side effects and risks associated with SRM using stratospheric aerosols. Briefly the possible side-effects identified to date are: 

(a) Imperfect cancellation (over-compensation) of important facets of climate 

change, including regional temperature patterns, but more seriously of the regional 

and seasonal distribution of precipitation (rainfall) especially at low latitudes. It 

should be noted that rainfall is notoriously difficult to predict in all weather forecasting and climate models anyway, and the reliable prediction of the effects of SRM 
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intervention is similarly difficult. Advances in computer modelling are required for 

all of these purposes. 

(b) Reduction of stratospheric ozone levels. 

(c) Possible modification of high-level tropospheric clouds (with consequences for 

climate which have not yet been evaluated). 

(d) SRM methods have no effect on CO2 levels and therefore do almost nothing 

to ameliorate ocean acidification. 

The most serious risk is however that SRM techniques ‘‘would create an artificial, 

approximate, and potentially delicate balance between increased greenhouse gas 

concentrations and reduced solar radiation, which would have to be maintained, potentially for many centuries. It is doubtful that such a balance would really be sustainable for such long periods of time, particularly if emissions of greenhouse gases 

were allowed to continue or even increase.’’ Moreover, if the intervention were terminated for any reason, all the climate change to be expected from the elevated 

level of GHGs still in the atmosphere would then occur very rapidly indeed (this 

is the ‘‘termination problem’’).

Q3. During your ‘‘Working Group’’ deliberations, were there any discussions surrounding liability? For example, if one nation were to act, using a stratospheric 

aerosol method, and several nations gained from the resultant ‘‘cooling’’, but 

there were unintended negative impacts as well, would each nation be liable in 

some way or just the one nation taking the action? How would the liability or 

remediation be shared?

A3. We did discuss liability issues briefly (see sections 4.5 and 5.4 of the report) but 

did not feel able to offer firm conclusions on this difficult subject (which also already 

arises, of course, over liability for the impacts of climate change itself). As with climate change, it is likely to be extremely difficult to attribute specific events causing 

losses to the intervention undertaken, with sufficient confidence to underpin a system for compensation. It may be more practicable to establish a generic system, 

similar to that which is evolving under the UNFCCC for compensation for the impacts of climate change on vulnerable communities.
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ANSWERS TO POST-HEARING QUESTIONS

Responses by Lee Lane, Co-Director, American Enterprise Institute (Aei) 

Geoengineering Project

Questions submitted by Chairman Bart Gordon

Q1. Please describe what you think a comprehensive federal research program on 

geoengineering should entail. What are the critical features of such a program?

A1. Overview: Such a program should include both scientific research and technology development. Over time, resource allocation should shift from the former to 

the latter. Research should explore both the possible benefits and the possible risks 

of geoengineering options. Both solar radiation management (SRM) and air capture 

(AC) deserve to be explored, but the former is far more important and less likely 

to win adequate private sector support; it should receive the lion’s share of the public funding. The SRM program will eventually entail field testing. The scale of the 

testing should gradually increase. To advance SRM, the U.S. government will need 

to build its capacity to model and to observe Earth’s climate.

Three broad principles are crucial:

First, the solar radiation management (SRM) R&D program should be organized 

separately from the air capture (AC) R&D program. Exploring SRM entails tasks 

that differ from those needed to explore AC. Disparate tasks demand disparate 

skills. Also, if research on AC were ever to be successful it might well devolve to 

the private sector; whereas, SRM is likely to remain under direct government control. Yoking together two such different efforts would be certain to impede the 

progress of both. 

Second, each program should have a clearly defined and accountable ‘‘owner’’. He 

or she must be accountable for project performance: therefore, he or she must also 

be able to allocate the available budget. The R&D process is uncertain; surprises 

are inevitable; therefore, managers must be free to respond to them. 

Third, Congress, too, would have to play a part in the success of R&D on 

geoengineering. R&D involves failures; indeed, an R&D program that experiences 

no failures is almost certainly too conservative. Members of Congress may be tempted to react to agency failures in ways that reinforce this tendency. The temptation 

to view R&D through the lens of local jobs is another notorious source of R&D inefficiency.

Q1a. Which U.S. agencies would contribute to a research initiative, and in what capacity?

A1a. For SRM, R&D will involve Earth observation, modeling, and several different 

areas on scientific research. NASA, NOAA, and NSF all possess relevant expertise. 

As R&D progresses, skill in managing technology development will play a growing 

role. Few civilian agencies of the U.S. government have demonstrated talent for 

tasks of this kind. 

A critical issue will be to choose the project’s lead agency. The lead agency should 

have a budget that allows it to draw on the expertise available in other government 

agencies without granting any of them the status of monopoly supplier. Congress 

would need to refrain from allocating tasks and dollars to favored agencies and facilities.

Q1b. What scale of investment would be necessary, both initially and in the longer 

term?

A1b. Initially, a few million dollars a year would suffice. At some point, SRM would 

require sub-scale testing. Eventually a full scale test might be warranted. These 

tests, and the needed global observation, could eventually cost several billion annually. Seeking alternatives to satellite observation might be an important cost saving 

R&D task. At least some experts believe that such alternatives exist.

Q1c. What kind of professional and academic expertise would be required?

A1c. The natural scientists on the panel are better qualified than Ito respond to this 

question as it pertains to those disciplines; however, Professor Fleming has observed 

that geoengineering also poses a number of questions that fall within the ambit of 

the social sciences. On this point, he is, I believe, correct. How government should 

respond to this need is an open question. In an earlier era, with the RAND Corporation, the U.S. government had great success in productively using social science. The 

Committee is, I believe, going to be hearing from Dr. Thomas Schelling. Dr. Schel-
115

ling has had experience with RAND and with other similar ventures. The Committee might wish to draw on his views on this subject. 

One fundamental question about SRM is the way in. which it should be integrated 

with other means of coping with climate change. While the natural sciences provide 

important inputs to answering this question, economists, decision theorists, and political scientists also have crucial contributions to make.

Q2. Please prioritize the geoengineering strategies you believe warrant extensive research, and explain your reasoning.

A2. SRM may offer a defense against the possible onset of rapid and very harmful 

climate change. Should such climate change occur, no other response appears to 

offer a comparable option for avoiding harm. This feature of SRM, combined with 

its apparently low cost, makes exploring it a high priority. AC may also warrant 

R&D, but does not offer either of these advantages; further, the private sector has 

fairly strong economic incentives to explore AC. In contrast, if we are to have an 

SRM option, the public sector will have to develop it.

Q2a. Within these, please highlight examples of potential negative impacts you predict might accompany their deployment and/or large-scale research.

A2a. Professor Robock has developed an extensive list of possible objections. This 

list constitutes a starting point for the defensive research agenda associated with 

SRM. I have nothing to add to his list. 

In the case of AC, most of the technologies entail relatively localized impacts; 

however, to have a global scale impact, AC must capture and safely store truly gargantuan quantities of mass. The shear scale of the task seems to dictate that its 

environmental costs will be substantial.

Q2b. Are there any strategies that you believe should be eliminated from consideration due to unacceptable risks and costs?

A2b. For reasons laid out in a recent paper (Bickel and Lane, 2009) the space sunshade concept is an unappealing approach to SRM. It offers few benefits that might 

not be achieved at vastly lower costs with other SRM techniques, and the very large 

up-front infrastructure costs would simply be so much waste if the project were to 

fail or be abandoned for any reason.

Q3. Could some geoengineering activities be confined to specific geographic locations?

A3. My understanding is that Dr. Michael MacCracken has been considering some 

SRM options for localized interventions. See: MacCracken, Michael, C. ‘‘On the possible use of geoengineering to moderate specific climate change impacts.’’ Environ. 

Res. Lett. 4 (2009), 045107, available at: http://www.iop.org/EJ/article/1748-9326/

4/4/045107/er19¥4¥045107.html#er1317855s3

Another line of research has been summarized in recent work by Rasch, Latham, 

and Chen. See: Rasch, Philip J., John Latham, and Chih-Chieh (Jack) Chen. 

‘‘Geoengineering by cloud seeding: influence on sea ice and climate system.’’ Environ. Res. Lett. 4 (2009), 045112, available at: http://www.iop.org/EJ/article/1748-

9326/4/4/045112/er19¥4¥045112.pdf?request-id=dc8ba35701-01a3-4aec-b654-

eee98f4a8a71

The Committee may wish to query these scholars on the results of their findings.

Q3a. For example, could solar radiation management be localized specifically for the 

protection of polar ice? If so, how?

Q4. In his submitted testimony, Dr. Robock explained simply: ‘‘To actually implement geoengineering, it needs to be demonstrated that the benefits of 

geoengineering outweigh the risks.’’

A4. The potential net benefits of SRM are, however, very large. One recent study 

found that, globally, the difference between the benefits of deploying SRM and the 

direct costs of doing so range from $200 billion to $700 billion a year in perpetuity. 

If other studies confirm this result, SRM should be deployed unless its side-effects 

entail annual net costs of at least $200 to $700. Determining if they do is a key 

part of a research agenda for exploring this option. (Professor Eric Bickel of the University of Texas at Austin is currently doing innovative work in this field, and the 

Committee might wish to consult him on these matters.) 

Research of this kind must also encompass the indirect benefits of deploying SRM, 

e.g. lowering the risk of trade wars triggered by GHG controls, the ecologic havoc 

wreaked by biofuel mandates, and so forth. No valid study can weigh only the indirect costs of SRM while ignoring those of other approaches.
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Q4a. What do you believe are the ‘‘tipping points’’ that would justify large-scale deployment of geoengineering?

A4a. The natural scientists on the panel are better qualified than Ito respond to 

this question.

Q4b. Based on the current pace of carbon increases (about 2 parts per million a year) 

and your prediction of the efficacy of conventional mitigation strategies, what 

would be an appropriate timeline for research and possible deployment?

A4b. Globally, no consensus exists about paying the costs of GHG controls, nor is 

such a consensus likely to emerge in less than several decades at the very least. 

Under these conditions, global emissions will continue rising for many decades to 

come. Atmospheric concentrations will continue rising until long after emissions 

have peaked. 

At the same time, research on SRM is likely to progress rather slowly. Larger 

scale field tests in particular might have to proceed at a deliberate pace. It would 

be better to observe the climate’s reaction to one intervention at a time and with 

a significant interval between interventions. The latter precaution would ensure 

that time-lagged impacts were discovered. This combination of factors implies that 

R&D on SRM should begin as soon as possible in order to allow the eventual field 

tests to proceed cautiously.

Q5. The effects of many geoengineering strategies such as stratospheric injections 

could not likely be tested at less than full-scale. To your knowledge, what types 

of international agreements would address the challenges of large-scale testing? 

Can you identify any existing treaties or agreements that would apply to largescale testing of geoengineering?

A5. In a recent paper prepared for the American Enterprise Institute, Professor 

Scott Barrett of Columbia University observed:

‘‘According to Daniel Bodansky (1996: 316), ‘‘international law has relatively little specific to say about climate engineering.’’ Moreover, he adds, ‘‘we should be 

cautious about drawing conclusions from existing rules, for the simple reason 

that these rules were not developed with climate engineering in mind’’ 

(Bodansky 1996: 316). Geoengineering creates a new institutional challenge.

Professor Barrett’s observations seem to suggest that no clear regime exists. SRM 

is a problem that is likely to require arrangements that are designed to fit its 

unique characteristics. 

I would reinforce the caution that I expressed in my written statement There is 

too much uncertainty about the nature of the U.S. national interest in 

geoengineering for the U.S. government to consider international agreements that 

might restrict our government’s future freedom of action.

Questions submitted by Representative Ralph M. Hall

Q1. Mr. Lane, would you expand on your comments in your testimony that a steep 

decline in greenhouse gas (GHG) emissions may well cost more than the perceived value of its benefits?

A1. Most economic studies of climate change have concluded that a policy of gradually restraining global GHG emissions would yield net benefits. These same studies 

indicate that attempts to apply more rapid emission restraints would be likely to 

impose costs that exceed their benefits. Professor Richard Tol’s recent paper for the 

Copenhagen Consensus Center basically reaffirms this consensus. 

A few studies have departed from this consensus. Some of these, like the analyses 

of Lord Stern and. William Cline, produce different results largely because of atypical assumptions about the rate at which future benefits should be discounted. William Nordhaus of Yale has presented a cogent critique of this approach. It is my 

personal impression that, on this point, at least here in the U.S., most economists 

who have examined the question, although not all of them, would favor the basic 

thrust of Nordhaus’ analysis over that offered by Stern and Cline. 

On a different point, Professor Martin Weitzman of Harvard has argued that the 

possible harm from low-probability, but very high-impact, climate change events is 

so great that benefit-cost analysis becomes, in his view, a poor guide to policy. Other 

economists, including Nordhaus, disagree. Debate continues, but unless GHG controls have a large impact on the trend in emissions, they might have little probability of lowering the risk of high-impact climate change. Nothing in the last twenty years’ history of GHG control talks suggests that controls will, in fact, produce 

sharp reductions in emissions. 
117

Finally, but perhaps most importantly, how GHG controls are structured will 

have a major effect on their costs. GHG control policies that are overly stringent, 

or those that fall unevenly across countries or economic sectors, will drastically raise 

the costs of reaching any given emission reduction target. Unfortunately, both globally and in the U.S., GHG controls are taking on exactly these cost increasing features. China’s and India’s refusal at the Copenhagen climate talks to make firm 

commitments or to pledge more than business-as-usual steps guarantees that either 

GHG controls will have virtually no effect on emissions or that they will do so only 

at an exorbitant cost.

Q2. How do you see R&D informing or defining the scope of the potential problems 

associated with solar radiation management (SRM)?

A2. Current climate models do a poor job of replicating regional rainfall patterns. 

Yet changes in regional rainfall, if they occur, are likely to account for the most economically significant unwanted side effect of SRM. Without improved models, it will 

be impossible to determine if a problem exists and, if it does, how severe it might 

be. With all of the potential drawbacks of SRM, the initial scientific research should 

then supply inputs for studies monetizing any costs that are found. 

Where research finds real problems with current SRM, concept redesign may 

avoid them. Alternatively, new SRM concepts might avoid problems; thus, earlier 

defensive research may partly shape the course of development.

Q3. While the U.S. is party to many international treaties, some of the more significant ones are agreements that we have not been able to sign on to, like the Law 

of the Sea.

a. How does this affect our future abilities to develop international governance 

and regulatory structures to address development and deployment of 

geoengineering technologies?

A3. Agreements designed for other purposes, as suggested by Dr. Bodansky, may 

fit awkwardly with the features of SRM. A workable SRM option would not require 

universal participation. Indeed, if transaction costs of managing the system were to 

be kept within reason, a relatively small subset of major powers would have to assume disproportionate authority over its operations. For the ‘‘governance’’ arrangements for SRM, a coalition of the willing might be a better model than agreements 

based on the fiction of international equality.

Q3b. How soon should these international negotiations begin? Before the technologies 

are deemed feasible by research? Or should we wait until the technology is mature enough to be considered deployable?

A3b. The U.S. interest in the various kinds of geoengineering remains unclear. It 

is clear, however, that the concept of geoengineering as a weapon is nonsense, but 

it is also clear that the benefits and costs of geoengineering are likely to vary from 

country to country. U.S. interests in the future development of this concept may, 

therefore, differ from those of other countries; yet the substance and the form of a 

possible international regime on geoengineering would be likely to affect the course 

of its development. Indeed, a regime that did not have such an effect would be a 

waste of effort. The U.S. government should acquire substantially more knowledge 

about geoengineering’s potential benefits and risks before embarking on any talks 

that might restrict its future freedom of action.
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ANSWERS TO POST-HEARING QUESTIONS

Responses by Alan Robock, Professor, Department of Environmental Sciences, School 

of Environmental and Biological Sciences, Rutgers University

Questions submitted by Chairman Bart Gordon

As stated in my original testimony, geoengineering proposals can be separated 

into solar radiation management (by producing a stratospheric cloud or making low 

clouds over the ocean brighter) or carbon capture and sequestration (with biological 

or chemical means over the land or oceans). My expertise is in the first area. In 

particular, my work has focused on the idea of emulating explosive volcanic eruptions, by attempting to produce a stratospheric cloud that would reflect some incoming sunlight, to shade and cool the planet to counteract global warming. In these 

answers, except where indicated, I will confine my remarks to solar radiation management, and use the term ‘‘geoengineering’’ to refer to only it. I do this because 

it is the suggestion that has gotten the most attention recently, and because it is 

the one that I have addressed in my work.

Q1. Please describe what you think a comprehensive federal research program on 

geoengineering should entail. What are the critical features of such a program?

A1. A comprehensive federal research program should follow the advice of the policy 

statement on geoengineering endorsed by both the American Meteorological Society 

and the American Geophysical Union in 2009, who recommend:

1. ‘‘Enhanced research on the scientific and technological potential for 

geoengineering the climate system, including research on intended and unintended environmental responses.

2. ‘‘Coordinated study of historical, ethical, legal, and social implications of 

geoengineering that integrates international, interdisciplinary, and 

intergenerational issues and perspectives and includes lessons from past efforts to modify weather and climate.

3. ‘‘Development and analysis of policy options to promote transparency and 

international cooperation in exploring geoengineering options along with restrictions on reckless efforts to manipulate the climate system.’’

Being only an expert in the first category, I will confine my responses to those 

issues, but urge you to seek advice from historians, social scientists, and political 

scientists on items 2 and 3, which are also very important. 

A research program devoted to the scientific and technological potential should include computer modeling, engineering studies of systems that could create particles 

in the stratosphere or brighten clouds, and observing systems for marine stratocumulus clouds and stratospheric aerosols. 

State-of-the-art climate models, which have been validated by previous success at 

simulating past climate change, including the effects of volcanic eruptions, should 

be used for theoretical studies. They would consider different suggested scenarios 

for injection of gases or particles designed to produce a stratospheric cloud, and different scenarios of marine cloud brightening, and evaluate the positive and negative 

aspects of the climate response. So far, the small number of studies that have been 

conducted have all used different scenarios, and it is difficult to compare the results 

to see which are robust. Experiments should be coordinated among the different climate modeling groups that are performing runs for the Climate Modeling Intercomparison Project (CMIP) of the World Climate Research Programme Working 

Group on Coupled Modelling, described at http://cmip-pcmdi.11n1.gov/, for assessing climate models and their response to many different causes of climate change, 

including anthropogenic greenhouse gases and aerosols. As they explain at the 

above website, CMIP is ‘‘a standard experimental protocol for studying the output 

of coupled atmosphere-ocean general circulation models (AOGCMs). CMIP provides 

a community-based infrastructure in support of climate model diagnosis, validation, 

intercomparison, documentation and data access. This framework enables a diverse 

community of scientists to analyze GCMs in a systematic fashion, a process which 

serves to facilitate model improvement. Virtually the entire international climate 

modeling community has participated in this project since its inception in 1995.’’ Financial support from a national research program, in cooperation with other nations, will produce more rapid and more comprehensive results. The studies need 

to include advanced treatment of aerosol particles in climate models, including how 

they form and grow, as well as their effects on radiation and ozone. 
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Another area of research that needs to be supported under the first category is 

the technology of producing a stratospheric aerosol cloud. Robock et al. [2009] calculated that it would cost several billion dollars per year to just inject enough sulfur 

gas into the stratosphere to produce a cloud that would cool the planet using existing military airplanes. Others have suggested that it would be quite a bit more expensive. However, even if SO2 (sulfur dioxide) or H2S (hydrogen sulfide) could be 

injected into the stratosphere, there is no assurance that nozzles and injection strategies could be designed to produce a cloud with the right size droplets that would 

be effective at scattering sunlight. However, the research program will also need to 

fund engineers to actually build prototypes based on modification of existing aircraft 

or new designs, and to once again examine other potential mechanisms including 

balloons, artillery, and towers. They will also have to look into engineered particles, 

and not just assume that we would produce sulfate clouds that mimic volcanic eruptions. In addition, engineering studies will be needed for ships that could inject salt 

into marine clouds. 

At some point, given the results of climate models and engineering, there may be 

a desire to test such a system in the real world. But this is not possible without 

full-scale deployment, and that decision would have to be made without a full evaluation of the possible risks. Certainly individual aircraft or balloons could be 

launched into the stratosphere to release sulfur gases. Nozzles can be tested. But 

whether such a system would produce the desired cloud could not be tested unless 

it was deployed into an existing cloud that is being maintained in the stratosphere. 

While small sub-micron particles would be most effective at scattering sunlight and 

producing cooling, current theory [e.g., Heckendorn et al., 2009] tells us that continued emission of sulfur gases would cause existing particles to grow to larger sizes, 

larger than volcanic eruptions typically produce, and they would be less effective at 

cooling Earth, requiring even more emissions. Such effects could not be tested, except at full-scale. 

Furthermore, the climatic response to an engineered stratospheric cloud could not 

be tested, except at full-scale. The weather is too variable, so that it is not possible 

to attribute responses of the climate system to the effects of a stratospheric cloud 

without a very large effect of the cloud. Volcanic eruptions serve as an excellent natural example of this. In 1991, the Mt. Pinatubo volcano in the Philippines injected 

20 Mt (megatons) of SO2 (sulfur dioxide) into the stratosphere. The planet cooled 

by about 0.5° C (1° F) in 1992, and then warmed back up as the volcanic cloud fell 

out of the atmosphere over the next year or so. There was a large reduction of the 

Asian monsoon in the summer of 1992 and a measurable ozone depletion in the 

stratosphere. Climate model simulations suggest that the equivalent of one 

Pinatubo every four years or so would be required to counteract global warming for 

the next few decades, because if the cloud were maintained in the stratosphere, it 

would give the climate system time to cool in response, unlike for the Pinatubo case, 

when the cloud fell out of the atmosphere before the climate system could react 

fully. To see, for example, what the effects of such a geoengineered cloud would be 

on precipitation patterns and ozone, we would have to actually do the experiment. 

The effects of smaller amounts of volcanic clouds on climate can simply not be detected, and a diffuse cloud produced by an experiment would not provide the correct 

environment for continued emissions of sulfur gases. The recent fairly large eruptions of the Kasatochi volcano in 2008 (1.5 Mt SO2) and Sarychev in 2009 (2 Mt 

SO2) did not produce a climate response that could be measured against the noise 

of chaotic weather variability. 

Any field testing of geoengineering would need to be monitored so that it can be 

evaluated. While the current climate observing system can do a fairly good job of 

measuring temperature, precipitation, and other weather elements, we currently 

have no system to measure clouds of particles in the stratosphere. After the 1991 

Pinatubo eruption, observations with the Stratospheric Aerosol and Gas Experiment 

II (SAGE II) instrument on the Earth Radiation Budget Satellite showed how the 

aerosols spread, but it is no longer operating. To be able to measure the vertical 

distribution of the aerosols, a limb-scanning design, such as that of SAGE II, is optimal. Right now, the only limb-scanner in orbit is the Optical Spectrograph and InfraRed Imaging System (OSIRIS), a Canadian instrument on Odin, a Swedish satellite. SAGE III flew from 2002 to 2006, and there are no plans for a follow on mission. A spare SAGE III sits on a shelf at a NASA lab, and could be used now. There 

is one satellite in orbit now with a laser, but it is not expected to last long enough 

to monitor future geoengineering, and there is no organized system to use it to 

produce the required observations of stratospheric particles. Certainly, a dedicated 

observational program would be needed as an integral part of any geoengineering 

implementation.
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Q1a. Which U.S. agencies would contribute to a research initiative, and in what capacity?

A1a. The U.S. agencies most involved in climate modeling are the National Science 

Foundation (NSF), National Center for Atmospheric Research (funded mostly by 

NSF), National Oceanic and Atmospheric Administration, National Aeronautics and 

Space Administration (NASA), and Department of Energy (DOE). I would recommend that NSF be in charge of a climate modeling research program, coordinated 

with the other agencies, with the Program for Climate Model Diagnosis and Intercomparison of the DOE continuing their program of archiving all the model output 

for intercomparisons. For the engineering studies, I recommend that NASA be in 

charge, in cooperation with the Department of Defense, which may be able to provide expertise in some of the proposed delivery systems. For an improved system 

of stratospheric aerosol observing, as well as better cloud observing from space, 

NASA should be in charge.

Q1b. What scale of investment would be necessary, both initially and in the longer 

term?

A1b. A geoengineering research program should not be at the expense of existing 

research into climate change, mitigation, and adaptation. Our first goal should be 

rapid mitigation, and we need to continue the current increase in support for green 

alternatives to fossil fuels. We also need to continue to better understand regional 

climate change, to help us to implement mitigation and adapt to the climate change 

that will surely come in the next decades no matter what our actions today. But 

a small increment to current funding to support geoengineering will allow us to determine whether geoengineering deserves serious consideration as a policy option. 

The total expenditure for climate model experimentation should be on the order of 

$10 million per year, which would include expanding current efforts as well as 

training of new scientists to work on these problems, through postdocs and graduate 

student fellowships. 

As for the engineering studies, you would have to ask engineering experts. Certainly studies should be done of the feasibility of retrofitting existing U.S. Air Force 

planes to inject sulfur gases into the stratosphere, as described by Robock et al.

[2009], as well as of developing new vehicles, probably remotely-piloted, for routine 

delivery of sulfur gases or production of aerosol particles. A separate engineering 

effort aimed at ships that could inject salt into marine clouds should be part of the 

effort. 

The dedicated observational effort described above would involve field campaigns 

to observe cloud experiments, which could probably be conducted with existing aircraft, but the campaigns would need to be funded. In addition, NASA needs to develop a robust, ongoing set of satellites to observe stratospheric aerosols, to prepare 

for the next volcanic eruptions, which serve as natural analogs for stratospheric 

geoengineering, as well as to monitor any in situ stratospheric experiments that 

may be conducted in the future. However, right now NASA could devote $1 million 

per year to just using current satellites to produce a continuous record of stratospheric aerosols and precursors. Many different observations are not being analyzed 

in a routine manner, and are only used by individual investigators to study specific 

cases, such as the Australian forest fires early in 2009 or the Kasatochi volcanic 

eruption of 2008. If a NASA-produced database were available routinely, much could 

be learned from these ongoing natural experiments. For new systems, experts on 

aircraft field campaigns and satellite development would need to be consulted about 

the costs.

Q1c. What kind of professional and academic expertise would be required?

A1c. Climate modelers; experts in atmospheric chemistry and aerosols; cloud physicists; specialists in aircraft and satellite observations; satellite, aircraft, balloon, artillery, and tower engineers; historians; social scientists; political scientists.

Q2. Please prioritize the geoengineering strategies you believe warrant extensive research, and explain your reasoning.

A2. Two types of solar radiation management, using stratospheric aerosols and marine cloud brightening, warrant extensive research. Both mimic observed changes in 

the atmosphere that have already occurred. We know that volcanic eruptions reduce 

solar radiation and cool the planet and we know that particles injected into marine 

stratocumulus clouds make them brighter, which presumably would cool the surface 

if there were no other compensating changed in the clouds. In both cases, there are 

no obvious serious side effects from the sulfur gases or salt proposed for the injections.
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Q1a. Within these, please highlight examples of potential negative impacts you predict might accompany their deployment and/or large-scale research.

A1a. Computer modeling research of stratospheric aerosols or marine cloud brightening would only have negative effects if it took resources, such as the time of scientists or computers, away from more productive activities. But if funded in addition to other ongoing climate research, it would enhance our understanding of the 

climate system both in theory and in enhanced observations. 

Actual deployment of either scheme into the atmosphere, however, would have the 

potential to produce serious side effects. That is why I advocate extensive computer 

modeling before any such decision is made, to better understand and quantify each 

of the potential problems. I have enumerated many potential negative impacts of 

stratospheric geoengineering in Robock [2008a, 2008b], so will only list them briefly 

here, from Robock et al. [2009]:

1. Drought in Africa and Asia

2. Continued ocean acidification from CO2

3. Ozone depletion

4. No more blue skies

5. Less solar power

6. Environmental impact of implementation

7. Rapid warming if stopped

8. Cannot stop effects quickly

9. Human error

10. Unexpected consequences

11. Commercial control

12. Military use of technology

13. Conflicts with current treaties

14. Whose hand on the thermostat?

15. Ruin terrestrial optical astronomy

16. Moral hazard - the prospect of it working would reduce drive for mitigation

17. Moral authority - do we have the right to do this?

As for marine cloud brightening, cooling over the oceans with persistent cloudiness might affect the entire oceanic biosphere and food chain. Because marine 

clouds would only be in certain locations, the differential cooling would change 

weather patterns. Jones et al. [2009] found in their climate model experiments that 

this could produce a drought in the Amazon rainforest, with devastating effects on 

the forests and other life there.

Q2b. Are there any strategies that you believe should be eliminated from consideration due to unacceptable risks and costs?

A2b. Angel [2006] proposed placing shades in orbit between the Sun and Earth to 

reduce the amount of insolation, but it would be very expensive and difficult to control, so I would not recommend research into this idea.

Q3. Could some geoengineering activities be confined to specific geographic locations?

A3. Marine cloud brightening could be conducted in specific locations, but that 

might not be very effective at dealing with global warming.

Q3a. For example, could solar radiation management be localized specifically for the 

protection of polar ice?

A3a. Not that I know of. Marine cloud brightening would not be effective in the Arctic, since there is no proposed technology to whiten clouds that would operate on 

ice in the Arctic. Furthermore, one would need clouds in the correct location in order 

to brighten them. In the Arctic, unlike off the west coasts of North and South America and Africa, marine stratocumulus do not persist as regularly in specific locations. In addition, because of the low angle of the Sun in the Arctic, changing cloud 

albedo would not be very effective. 

With respect to stratospheric aerosols, Robock et al. [2008c] showed that if 

aerosols were created in the Arctic stratosphere, while Arctic temperature could be 

controlled and sea ice melting could be reversed, there would still be large consequences for the summer monsoons over Asia and Africa, since the aerosols would 

not be confined to the polar region.
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Q3b. If so; how?

Q4. In your submitted testimony, you explained simply: ‘‘To actually implement 

geoengineering, it needs to be demonstrated that the benefits of geoengineering 

outweigh the risks.’’ What do you believe are the ‘‘tipping points’’ that would justify large scale deployment of geoengineering?

A4. The declaration of a planetary emergency that would justify large-scale 

geoengineering would require more climate research. While increased melting of 

Greenland or Antarctica along with rapidly rising sea level, or an increased frequency of severe hurricanes, droughts or floods, might appear to be a tipping point 

or an emergency, we would need much more research to quantify whether these 

changes were indeed caused by global warming and whether geoengineering would 

halt them. We would also have to be sure that the negative side effects of any proposed geoengineering would be much less than the problems it was attempting to 

solve, and that those affected by these actions would be fairly compensated.

Q4a. Based on the current pace of carbon increases (about 2 parts per million a year) 

and your prediction of the efficacy of conventional mitigation strategies, what 

would be an appropriate timeline for research and possible deployment?

A4a. No matter how effective conventional mitigation strategies prove to be in the 

next decade, the amount of global warming will be about the same, as the greenhouse gases already in the atmosphere will continue to cause warming. Mitigation 

will only make a difference in the longer term. So geoengineering research should 

not depend on the short-term political decisions in the next few years (and mitigation should definitely not wait for the possibility of safe and effective 

geoengineering). So independent of short-term changes in greenhouse gases emissions, I would recommend a 10-year research program that will use climate models 

to investigate the efficacy, risks, and costs of proposed geoengineering schemes, include technical research to determine whether it is even possible to implement the 

proposed schemes, and develop and deploy robust observing systems. This will allow 

policymakers to have enough information in a decade to decide whether 

geoengineering should ever be implemented as an emergency measure. Since these 

proposed schemes would work very quickly, within a year or two, this would leave 

enough time to adequately research them and still implement them before catastrophic climate change is likely.

Q5. The effects of many geoengineering strategies such as stratospheric injections 

could not likely be tested at less than full-scale. To your knowledge, what types 

of international agreements would address the challenges of large-scale testing?

A5. There are several current international treaties, such as the Montreal Protocol 

on Substances That Deplete the Ozone Layer, the Antarctic Treaty, the Law of the 

Sea, the Framework Convention on Climate Change, and Nuclear Test Ban treaties, 

that seek to limit environmental damage from human emissions. These treaties, 

while they do not apply directly to geoengineering, serve as a warning that humans 

can have a strong, inadvertent, negative impact on the environment, and that we 

must keep this in mind with respect to geoengineering. They also serve as models 

for the types of treaties that different nations can sign to agree to protect the environment.

Q5a. Can you identify any existing treaties or agreements that would apply to largescale testing of geoengineering?

A5a. I am not a lawyer, but the U.N. Convention on the Prohibition of Military or 

Any Other Hostile Use of Environmental Modification Techniques (ENMOD) may 

apply. The terms of ENMOD explicitly prohibit ‘‘military or any other hostile use 

of environmental modification techniques having widespread, long-lasting or severe 

effects as the means of destruction, damage, or injury to any other State Party.’’ 

Any geoengineering scheme that adversely affects regional climate, for example, producing warming or drought, would therefore violate ENMOD if done in a hostile 

manner, which would be difficult to determine. Therefore, new governance mechanisms would have to be developed before any experimentation in the atmosphere. 

SEE END OF DOCUMENT FOR ALL REFERENCES.

Questions submitted by Representative Ralph M. Hall

Q1. In your testimony, you indicate that one of the shortcomings of ‘‘solar radiation 

management’’ geo-engineering is that it could produce drought in Asia and Afri-
123

ca and threaten the food supply for billions of people. Some scientists have suggested that global climate change could have the same result; others have suggested that it will actually increase agricultural production in some areas of the 

world.

a. If we were to undertake some type of large scale geo-engineering experiment, 

how would we be able to differentiate between the effects of global climate 

change and those from the geo-engineering and make the necessary modifications to prevent catastrophe?

A1,1a. There is a certain natural variability of climate because of the chaotic nature 

of the atmosphere and oceans. This randomness limits our ability to make weather 

forecasts beyond about two weeks and limits our ability to make ocean forecasts, 

such for El Nin ̃no events, beyond about six months. So the attribution of particular 

weather and climate events, such as strong hurricanes, tornado outbreaks, droughts, 

and floods, to a particular geoengineering experiment or to the effects of greenhouse 

gases is not possible in the absolute sense and can only be done statistically. That 

is, theory (models) tell us that the probability of events like this would change in 

response to different things human might put into the atmosphere, but we cannot 

attribute any particular event to a particular cause. Therefore, a real-world 

geoengineering experiment would have to be conducted for a long time, 10 or 20 

years or longer, so as to gather enough data to calculate the statistics. It is only 

after 60 years of global warming since about 1950 and decades of the IPCC process 

that we have a clear understanding the greenhouse gases are responsible. 

The answer to the question would depend on what type of geoengineering were 

conducted, such as stratospheric aerosols or marine cloud brightening, and the 

strength of the geoengineering. For a massive injection of aerosols into the stratosphere, or massive seeding of clouds, the effects of geoengineering would be stronger 

and a shorter experiment would be needed to separate the effects from global warming. Climate model experiments will be able to give us a good idea of how strong 

and how long a real-world experiment would be needed to separate the effects from 

natural variability and from global warming.

Q1b. If we were able to differentiate between the effects of global climate change and 

effects from geoengineering, is it now possible to determine whether a drought 

is caused by anthropogenic climate change or just natural variability?

A1b. No. As explained above, the attribution of particular weather and climate 

events, such as strong hurricanes, tornado outbreaks, droughts, and floods, to a particular geoengineering experiment, to the effects of greenhouse gases, or just to natural variability is not possible in the absolute sense and can only be done statistically. That is, theory (models) tells us that the probability of events like this would 

change in response to different things human might put into the atmosphere, but 

we cannot attribute any particular event to a particular cause. For example, what 

if we start geoengineering and we get a reduction of summer monsoon rainfall in 

India for two out of the first five years? Could this have happened by chance, or 

was it caused by the geoengineering? We could not answer that question without 

many more years of experimentation in the real world. However, we could easily do 

that experiment in climate models.

Q2. In your testimony you indicate that you have been using NASA climate models 

and NASA computers to conduct climate model simulations. You also indicate 

that increases in funding for research are necessary to explore these concepts further.

a. Do you believe much of this research can be done utilizing existing resources 

such as those at NASA?

A2,2a. No. Climate modeling needs to be done at many different research centers 

with many different climate models, and the results compared to be sure they are 

robust. This is the current strategy of CMIP, as discussed in detail in the answer 

to Mr. Gordon’s question 1 above. 

All the world climate modeling groups are currently finalizing their latest model 

versions so that they can begin a suite of experiments, called CMIP–5, in preparation for the next Intergovernmental Panel on Climate Change report. While NASA 

and other climate modeling centers in the United States, such as at the National 

Oceanic and Atmospheric Administration (NOAA) Geophysical Fluid Dynamics Laboratory. and the National Center for Atmospheric Research do not need new resources to complete their model development, the current scientists working there 

are completely occupied with the CMIP–5 experiments. They would need more personnel and computer resources to complete additional geoengineering experiments.
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Q2b. What additional resources and capabilities would be required to further research in this area?

A2b. This question is completely answered in response to questions 1 and 2 of Mr. 

Gordon above, and I refer you to those answers.

Q2c. Are these models peer reviewed? Are you privy to the assumptions that go into 

building the models before you run your simulations?

A2c. Absolutely yes. The climate model we are currently using, Goddard Institute 

for Space Studies ModelE, is described in peer-reviewed publications by Schmidt et 

al. [2006], Russell et al. [1995], and Koch et al. [2006]. We and anyone else who 

reads these papers completely understand the assumptions that go into them. Furthermore, this model is part of the CMIP experiments described above, and its capabilities are well known and documented.

Q3. In reading your testimony, one comes to the conclusion that regardless of how 

much research we perform ahead of time, we will never really know the true effects geo-engineering would have on the planet without actually doing it because 

of all the possible variables. Is that an accurate statement? How accurate is that 

for other technological ventures we have undertaken?

A3. I guess that depends on what ‘‘know the true effects’’ means. Indeed we would 

learn a lot by experimenting in the real world and would be able to compare the 

responses to those obtained theoretically by climate modeling. But as explained 

above, there is a certain natural variability of climate because of the chaotic nature 

of the atmosphere and oceans. This randomness limits our ability to make weather 

forecasts beyond about two weeks and limits our ability to make ocean forecasts, 

such for El Nino events, beyond about six months. So the attribution of particular 

weather and climate events, such as strong hurricanes, tornado outbreaks, droughts, 

and floods, to a particular geoengineering experiment or to the effects of greenhouse 

gases is not possible in the absolute sense and can only be done statistically. That 

is, the probability of events like this would change in response to different things 

human might put into the atmosphere. Therefore, a real-world experiment would 

have to be conducted for a long time, 10 or 20 years or longer, so as to gather 

enough data to calculate the statistics. For example, what if we start geoengineering 

and we get less drought in California for three out of the first five years. Could this 

have happened by chance, or was it caused by the geoengineering? We could not answer that question without many more years of experimentation in the real world. 

However, we could easily do that experiment in climate models. 

As for other technical ventures, it would depend on the technology, and I am not 

an qualified to answer the question in general. But I would like to say that some 

experiments should never be conducted in the real world. For example, I have conducted a lot of research on the climatic effects of nuclear weapons. If used in warfare, the fires they would ignite would produce so much smoke that climate models 

tell us that the cold and dark at the Earth’s surface would severely impact agriculture and even produce a nuclear winter [Robock et al., 2007a, 2007b]. This is an 

experiment we should never try to verify in the real world.

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Angel, R. (2006), Feasibility of cooling the Earth with a cloud of small spacecraft 

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Heckendorn P., et al. (2009), The impact of geoengineering aerosols on stratospheric 

temperature and ozone, Environ. Res. Lett., 4; 045108, doi:10.1088/1748-9326/4/

4/045108.

Jones, A., J. Haywood, and O. Boucher (2009), Climate impacts of geoengineering 

marine stratocumulus clouds, J. Geophys. Res., 114, D10106, doi:10.1029/

2008JD011450.

Koch, D., G. A. Schmidt, and C. V. Field (2006), Sulfur, sea salt, and radionuclide 

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(2007a), Climatic consequences of regional nuclear conflicts. Atm. Chem. Phys., 

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ANSWERS TO POST-HEARING QUESTIONS

Responses by James Fleming, Professor and Director, Science, Technology and Society Program, Colby College

Questions submitted by Chairman Bart Gordon

Q1. Please describe what you think a comprehensive federal research program on 

geoengineering should entail. What are the critical features of such a program?

A2. The American Meteorological Society’s Statement on Geoengineering http://

www.ametsoc.org/policy/2009geoengineeringclimate¥ansstatement.html (also approved by the American Geophysical Union) recommends that proposals to 

geoengineer climate require more research of an interdisciplinary nature, cautious 

consideration, and appropriate restrictions. Here are their summary recommendations:

a. Enhanced research on the scientific and technological potential for 

geoengineering the climate system, including research on intended and unintended environmental responses.

b. Coordinated study of historical, ethical, legal, and social implications of 

geoengineering that integrates international, interdisciplinary, and 

intergenerational issues and perspectives and includes lessons from past efforts to modify weather and climate.

Development and analysis of policy options to promote transparency and international cooperation in exploring geoengineering options along with restrictions on 

reckless efforts to manipulate the climate system. 

Geoengineering, understood as purposeful manipulation of the global climate and 

biophysical systems of the entire Earth by a particular project or entity, however 

well intentioned, could lead to international conflict and unpredictable ecological 

disasters. Humans know far too little about the climate system to imagine that any 

large-scale intervention would have the desired result, or even a predictable result. 

Any nation engaging in global-scale geoengineering could be placing itself and all 

other life on the plant in jeopardy. 

The famous mathematician John von Neumann called climate engineering a ‘‘thoroughly ‘abnormal’ industry,’’ arguing that large-scale interventions, especially solar 

radiation management, were not necessarily rational undertakings and could have 

‘‘rather fantastic effects’’ on a scale difficult to imagine. Tinkering with the Earth’s 

heat budget or the atmosphere’s general circulation, he said, ‘‘will merge each nation’s affairs with those of every other, more thoroughly than the threat of a nuclear 

or any other war may already have done’’—and possibly lead to ‘‘forms of climatic 

warfare as yet unimagined.’’ In this sense, geoengineering is potentially more powerful and more destructive than an arsenal of H-bombs. Since some forms of solar 

radiation tinkering could be undertaken by private entities or rogue nations unilaterally and relatively cheaply, what is urgently needed is research, discussion, and 

education on all the possible things that are wrong with such a technocratic approach to thinking about climate change. As Harry Wexler once said, ‘‘the human 

race is poised precariously on a thin climatic knife-edge.’’ One of the worst climatic 

disasters imaginable involves destabilizing the climate system, damaging stratospheric ozone, triggering drought, and otherwise destroying our relationship with 

the sky by misplaced climate tinkering. 

Therefore, a comprehensive research program in geoengineering cannot be merely 

a scientific and technically-based effort. It must be led by historically-informed humanistic and social science efforts to understand the precedents and contextualize 

human desires (and hubris) involved in intervening in natural systems. Such discussions should seek to avoid being dominated by Western technocratic influences, and 

would need to be fully international, interdisciplinary, and intergenerational in nature so that a global conversation emerges. 

In this sense, no technical agency in the U.S. or elsewhere has the capacity to 

lead such an effort. More likely international scholarly, humanitarian, and governance organizations would have to pool their resources in such an undertaking. Any 

scientific or technical research on geoengineering should be conducted only as part 

of the mainstream effort in atmospheric science. It should not be in any way be a 

secret effort within DoD, or a single or multi-agency effort funding mainly enthusiasts for the techniques. It should be spearheaded in the U.S. by NSF, which has 

the best open peer review practices and which also sponsors the National Center 

for Atmospheric Research (NCAR). NSF has the added virtue of funding social, eco-
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nomic, and behavioral studies (including Science Studies) and NCAR maintains a 

unit specializing in environmental and social impacts. 

Support is urgently needed for historical studies of existing environmental treaties, international accords, and efforts to govern new technologies. These would include the 1978 UN Convention on the Prohibition of Military or Any Other Hostile 

Use of Environmental Modification Techniques (ENMOD), the Antarctic Treaty, the 

Law of the Sea, the Peaceful Uses of Outer Space, and gatherings such as the 1975 

conference in Asilomar, California on recombinant DNA. This would be followed by 

meetings of historians, ethicists, social scientists, and policy experts from around 

the world for interdisciplinary discussion and recommendations. Funding for a program involving about 10 core staff, office support, a variety of conferences, and a 

publishing program with peer-reviewed reports and volumes may be able to function 

for approximately $2 million per year or ten times this amount for a robust international effort. To foster historical, humanistic, social, public policy, and governance 

discussions, the Woodrow Wilson International Center for Scholars is a likely venue. 

It could serve as a scholarly, non-partisan integration point for related efforts at 

other institutions. Investment in this program would not require much if any hardware purchases or facilities, but should involve a full program of conferences, meetings, seminars and high-level consultations. It should have a director and staff, senior and junior fellows, affiliated members from around the world, and internships 

and other student opportunities. 

Geoengineering research is currently not ready, and may never be ready for any 

field testing, large scale or otherwise. It is best done indoors using computer simulations and in other controlled conditions, such as laboratories and wind tunnels. For 

decades, verification of weather modification experiments has been stymied by natural variability in cloud and weather conditions. The same is true many times over 

for experiments on the global climate. 

What is most needed in atmospheric science today is more focused and basic research on atmospheric dynamics and chaotic forcings. If, as Edward Lorenz maintained, the climate system exhibits modes that are extremely sensitive to perturbations, what unknown effect might a sulfate cannon in China, Russia, or perhaps 

Livermore, California have on the global or regional climate? Also needed, especially 

now, is a concerted effort to restore scientific and public confidence in the atmospheric sciences, their peer review practices, Earth’s instrumental and proxy temperature records, and the authority and behavior of computer models and their results. The Earth orbiting satellite monitoring gap identified in the National Academy’s Decadal Survey (2007) also needs to be addressed. This effort alone may involve approximately doubling the current support for basic research, or about $1–

2 billion per year. 

So in summary, $2–20 million for open conferences on social aspects and governance, and $1–2 billion for basic peer-reviewed research on and monitoring of the climate system seem to be in order.

Q2. Please prioritize the geoengineering strategies you believe warrant extensive research, and explain your reasoning.

A2a. As described above, concerted study of the history, social aspects, and governance of technological interventions and geoengineering proposals, past and present, 

to cast a new light on just what is being proposed. 

b. As described above, increased capacity in basic atmospheric science and climate 

monitoring, in which model geoengineering proposal play a role, but only a role in 

a better understanding of the planet. 

c. All of the proposed techniques of solar radiation management (SRM) and carbon 

capture and sequestration (CCS) have many, many serious and unexamined problems. None are really cheap, because economists have only looked at direct costs, 

not at potential damages. None are ready for field testing or deployment. All of the 

techniques might well be researched using models and laboratory experiments. For 

example:

Space mirrors. In 1989 James Early, a scientist from Lawrence Livermore National Laboratory, revisited the issue of space mirrors (first proposed in the 1920s) 

and linked space manufacturing fantasies with environmental issues in his wild 

speculations on the construction of a solar shield ‘‘to offset the greenhouse effect.’’ 

His back-of-the-envelope calculations indicated that a massive shield some 1,250 

miles in diameter would be needed to reduce incoming sunlight by 2 percent. He 

estimated that an ultra-thin shield, possibly manufactured from lunar materials 

using nano-fabrication techniques, might cost ‘‘from one to ten trillion dollars.’’ 

Launched from the moon by an unspecified ‘‘mass driver,’’ the shield would reach 

a ‘‘semi-stable’’ orbit at the L1 point one million miles from Earth along a direct 
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line toward the Sun, where it would perch ‘‘like a barely balanced cart atop a steep 

hill, a hair’s-width away from falling down one side or the other.’’ Here it would be 

subjected to the solar wind, harsh radiation, cosmic rays, and the buildup of electrostatic forces. It would have to remain functional for ‘‘several centuries,’’ which would 

entail repair missions. It would also require an active positioning system to keep 

it from falling back to Earth or into the Sun. Early did not indicate what a guidance 

system might look like for a 5 million square mile sheet of material possibly thinner 

than kitchen plastic wrap, with a mass close to a billion kilograms (2.2 billion 

pounds in Earth gravity). In other words, it was not feasible. A recent update of 

this proposal by Roger Angel fares no better. 

Stratospheric Aerosols. Using guns, rockets, or balloons to maintain a dust or 

aerosol cloud in the stratosphere to increase the reflection of sunlight may sound 

cheap and appealing, but it is far from rational and may have many unwanted an 

unexpected side effects. Geoengineering advocate Lowell Wood has proposed attaching a long hose to a nonexistent but futuristic military High Altitude Airship (a 

Lockheed-Martin/DOD stratospheric super blimp now on the drawing board with 

some twenty-five times the volume of the Goodyear blimp) to ‘‘pump’’ reflective particles into the stratosphere. According to Wood, ‘‘Pipe it up; spray it out!’’ Wood has 

worked out many of the details—except for high winds, icing, and accidents, since 

the HAAs are likely to wander as much as 100 miles from their assigned stations. 

Imagine a 25-mile long hose filled with ten tons of sulfuric acid ripping loose, writhing wildly, and falling out of the sky. Environmental problems from such techniques 

(as documented by Alan Robock) include damage to tropical rainfall patterns, unwanted stratospheric ozone depletion, and regional effects that may lead to international disagreements. 

Air capture of carbon dioxide, with long-term storage. Klaus Lackner of the 

Earth Institute at Columbia University, collaborating with Tucson, Arizona-based 

Global Research Technologies, envisions a world filled with millions of inverse chimneys, some of them over 300 feet high and 30 feet in diameter, inhaling up to 30 

billion tons of carbon dioxide from the atmosphere every year (the world’s annual 

emissions) and sequestering it in underground or undersea storage areas. Lackner 

has built a demonstration unit in which a filter filled with caustic and energy intensive sodium hydroxide can absorb the carbon dioxide output of a single car. He admits, however, that this system is not safe or practical, so he is currently looking 

into proprietary ‘‘ion-exchange resins’’ with undisclosed energetic and environmental 

properties. Of course, the capture, cooling, liquefaction, and pumping of 30 billion 

tons of atmospheric carbon 

dioxide (the world’s annual emissions) would require an astronomical amount of 

energy and infrastructure, and it is not at all certain that Earth has the capacity 

for safe long-term storage of such a large amount of carbon.

Q3. Could some geoengineering activities be confined to specific geographic locations?

A3. No. If they could, they would not be ‘‘geo’’—scale engineering. Also, the Earth’s 

atmosphere is a fluid system that interacts and exchanges energy, mass, and momentum. Interventions in the radiation budget anywhere will trigger changes in the 

general circulation, including changes in stoma tracks and in particular storms and 

precipitation patterns. Proposals to restrict aerosol injections to the Arctic circle do 

not address the global spread of matter in the stratosphere or the interaction of air 

masses across latitudes. An imaginary Arctic forecasting center with authority to 

trigger stratospheric aerosol attacks is far beyond modem operational meteorology. 

Understanding and prediction are what is needed. Intervention and control are not 

really possible.

Q4. In his submitted testimony, Dr. Robock explained simply, ‘‘To actually implement geoengineering, it needs to be demonstrated that the benefits of 

geoengineering outweigh the risks.’’ [Questions on tipping points and timeline for 

research and deployment].

A4. Dr. Robock has published ‘‘20 Reasons Why Geoengineering May Be a Bad 

Idea.’’ His list includes the following:

(1) Potentially devastating effects on regional climate, including drought in Africa and Asia, (2) Accelerated stratospheric zone depletion, (3) Unknown environmental impacts of implementation, (4) Rapid warming if deployment ever stops, 

(5) Inability to reverse the effects quickly, (6) Continued ocean acidification, (7) 

Whitening of the sky, with no more blue skies, but nice sunsets, (8) The end 

of terrestrial optical astronomy, (9) Greatly reduced direct beam solar power, 

(10) Human error, (11) The moral hazard of undermining emissions mitigation, 
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(12) Commercialization of the technology, (13) Militarization of the technology, 

(14) Conflicts with current treaties, (15) Who controls the thermostat? (16) Who 

has the moral right to do this? (17) Unexpected consequences.

Some of these results (1–5) are derived from general circulation model simulations 

and others (6–9) from back-of-the-envelope calculations; most, however (10–17), 

stem from historical, ethical, legal, and social considerations. Regarding item (8), 

most enthusiasts for solar radiation management have overlooked its ‘‘dark’’ side: 

the scattering of starlight as well as sunlight, which would further degrade seeing 

conditions for both ground-based optical astronomy and general night sky gazing. 

Imagine the outcry from professional astronomers and the general public if the 

geoengineers pollute the stratosphere with a global sulfate cloud; imagine a night 

sky in which sixth-magnitude stars were invisible, with a barely discernable Milky 

Way, and fewer visible star clusters or galaxies. This would constitute a worldwide 

cultural catastrophe. 

Since global climate change is forced by a combination of natural and human factors, since it is a relatively slowly developing problem, and since it will affect different nations and groups differently, there is no clear ‘‘cliff’’ or readily defined ‘‘tipping point,’’ beyond which the sulfate cannons should roar. Mitigation and adaptation are the best strategies, so no lines in the sand can yet be set. The 1992 UN 

Framework Convention on Climate Change requires the ‘‘stabilization of greenhouse 

gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.’’ No one has yet defined ‘‘dangerous,’’ but attempts have been made to set the goal at 2 degrees of warming or 

350 or 450 ppm CO2. SRM does not stabilize greenhouse gas concentrations at all, 

it does not help with ocean acidification, and it may in its own right be considered 

‘‘dangerous anthropogenic interference with the climate system.’’ CCS maybe possible, but the energetics, cost, and stability of long term sequestration, with giant 

pools of CO2 underground remain unknown. 

The increase in CO2 concentration of 2 ppm per year is not in itself a significant 

problem. It is the sensitivity of the climate system to CO2 forcings (via water vapor, 

clouds, and other mechanisms) that is at issue. Efforts at mitigation and adaptation 

must be bipartisan and international; they must be given every possibility for success. Research in the historical, social, governance aspects of geoengineering should 

begin now, with the possibility left open that these technologies are too dangerous 

and unpredictable to govern. Also research into the negative side effects of 

geoengineering proposals should continue with modeling studies. There are no current prospects for responsible deployment of geoengineering techniques.

Q5. The effects of many geoengineering strategies such as stratospheric injections 

could not likely be tested at less than full scale. To your knowledge, what types 

of international agreements would address the challenges of large-scale testing?

A5. The 1978 UN Convention on the Prohibition of Military or Any Other Hostile 

Use of Environmental Modification Techniques (ENMOD) serves as a landmark 

treaty that may have to be revisited soon to avoid or at least try to mitigate both 

inadvertent harm or possible military or otherwise hostile use of climate control. 

This includes the governance and possible side effects of large-scale outdoor testing. 

If ‘‘climate change has the power to unsettle boundaries and shake up geopolitics, 

usually for the worse,’’ it is certain that the governments of the world will have 

their strategic military planners working in secret on both worst-case scenarios and 

technological responses. 

Chairman Gordon, the U.S. Congress can play a large role in supporting efforts 

to study the problems and limits of the non-existent technologies of geoengineering, 

but there is as yet no warrant for field testing or deployment.

Questions submitted by Representative Ralph M. Hall

Q1. Dr. Fleming, in your statement you include a short list of reasons that many 

people have claimed as the fundamental problems with climate engineering. Just 

to name a few, you mention the claims regarding lack of understanding, lack 

of technology, lack of political will to govern over it, etc.

a. Are these claims very similar to the ones people have heard every time a new 

technology or concept arises that threatens to alter our fundamental understandings of the universe?

b. How has society managed to get through those previous technological growth 

spurts?
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A1. Geoengineering does not ‘‘alter our fundamental understanding of the universe’’ 

in any Copernican sense. Nor is it a ‘‘quantum revolution’’ or in any way comparable 

to famous discoveries or theories, such as evolution, relativity, or plate tectonics. It 

is not a scientific discover at all, but a set of speculative intervention strategies with 

potential military implications. In the past new technologies such as radio or transistors allowed us to communicate across the miles and to miniaturize electronic devices such as radios and computers. New drugs such as penicillin battled infections. 

While they needed regulation and some guidelines, they did not offer a global threat 

to the planet. Recombinant DNA is a new technology that required oversight and 

regulatory control. This was true in spades for nuclear power and nuclear weapons. 

Geoengineering comes closest to these types of dangerous technologies, but it is 

much, much more speculative, and as yet, it does not even exist! 

There is no one answer to how ‘‘society managed to get through those previous 

technological growth spurts.’’ I think each case is unique and requires special historical contextualization. In some cases, such as the use of the machine gun in the 

Anglo-Zulu War of 1879, that society did not ‘‘manage’’ very well. And civil society 

itself was lucky to survive the escalation of civilian aerial bombing that occurred 

during World War II.

Q2. Just for the sake of argument, if it was decided that such climate engineering 

projects needed regulation, which Federal agency would be the most appropriate 

to do it?

A2. This answer closely parallels my response to Congressman Gordon, which I 

hope you have in hand. No technical or regulatory agency in the U.S. or elsewhere 

has the authority or capacity to lead such an effort. Just as no nation has the authority to set the global temperature, even if it could. Study and discussion of 

geoengineering must be international, interdisciplinary, and intergenerational, with 

strong historical, social, and governance efforts leading the way. In the US, the NSF 

would be the best agency to study the issues, but regulation would have to be international, perhaps through UN mechanisms such as the ENMOD Convention.

Q3. I find it interesting that you state that the human dimension is the biggest 

wildcard in the whole climate change debate that essentially makes it unpredictable. One of the reasons the hearing is important is due to the concern that one 

nation, or even just one individual, could take it upon themselves to ‘‘fix the climate change problem’’ and utilize some technology that would have global effects.

a. Should we be looking at this issue as a national security problem? Not unlike 

a rogue state or terrorist group that releases a biological, chemical or nuclear 

weapon on some unsuspecting populace?

b. Could the actions of a lone ‘‘climate savior’’ have global effects that would rise 

to this level of concern? Or is the technology really not in a place where this 

is an issue now, but we should be discussing it for the future?

A3. Unilateral or rogue nation intervention in the global climate system is indeed 

possible and would raise very serious national and international security concerns, 

as John von Neumann in 1956 and many others have repeatedly pointed out. One 

problem is that such interventions may start out as well-intentioned, but the effects 

could be widespread, harmful, and unpredictable. That is, they might be indiscriminate. Other scenarios may include climate tinkering favoring one nation and harming another, for example by redirecting rainfall. Also attribution may be a real problem, given the large variability of weather and climate, so such tinkering may be 

hard to prove. A favorable result of this situation may be a desire to strengthen satellite or ground-based measuring and monitoring capabilities in order to detect such 

activity and take more measurements. In this sense it may resemble the need for 

verification schemes for other potential weapons systems. 

I think many of the recent and current geoengineering proposals have a tinge of 

‘‘climate savior’’ As (rightly or wrongly) alarm over global warming spreads, some 

climate engineers are engaging in wild speculation and are advancing increasingly 

urgent proposals about how to ‘‘control’’ Earth’s climate. They are stalking the hallways of power, hyping their proposals, and seeking support for their ideas about fixing the sky. The figures they scribble on the backs of envelopes and the results of 

their simple (yet somehow portrayed as complex) climate models have convinced 

them, but very few others, that they are planetary saviors, lifeboat builders on a 

sinking Titanic, visionaries who are taking action in the face of a looming crisis. 

They present themselves as insurance salesmen for the planet, with policies that 

may or may not pay benefits. In response to the question of what to do about climate change, they are prepared to take ultimate actions to intervene, even to do 
131

too much if others, in their estimation, are doing too little. We are already discussing these attitudes, and there may arise some day a need to stop even a wellintentioned action. Bill Gates is currently investing in geoengineering and may have 

such an attitude; while $25 million ‘‘Branson prize’’ for reducing global warming 

acts to encourage planetary tinkers, cum saviors. 

Ranking Member Hall, the U.S. Congress can play a large role in supporting efforts to study the problems and limits of the non-existent technologies of 

geoengineering, but there is as yet no warrant for field testing or deployment. 

(133)

Appendix 2: 

ADDITIONAL MATERIAL FOR THE RECORD
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GEOENGINEERING II: THE SCIENTIFIC BASIS 

AND ENGINEERING CHALLENGES 

THURSDAY, FEBRUARY 4, 2010

HOUSE OF REPRESENTATIVES, 

SUBCOMMITTEE ON ENERGY AND ENVIRONMENT

COMMITTEE ON SCIENCE AND TECHNOLOGY, 

Washington, DC.

The Subcommittee met, pursuant to call, at 10:03 a.m., in Room 

2318 of the Rayburn House Office Building, Hon. Brian Baird 

[Chairman of the Subcommittee] presiding.
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138

1 Albedo is measured on a scale from 0 to 1, with 0 representing the reflectivity of a material 

which absorbs all radiation and 1 represents a material which reflects all radiation. Newly laid 

asphalt has a typical albedo of ∼0.05 and fresh snow can have an albedo of 0.90.

HEARING CHARTER

COMMITTEE ON SCIENCE AND TECHNOLOGY

U.S. HOUSE OF REPRESENTATIVES 

Geoengineering II:

The Scientific Basis and Engineering Challenges 

THURSDAY, FEBRUARY 4, 2010

10:00 A.M.

2325 RAYBURN HOUSE OFFICE BUILDING

Purpose 

On Thursday, February 4, 2010, the House Committee on Science & Technology, 

Subcommittee on Energy and Environment will hold a hearing entitled 

‘‘Geoengineering II: The Scientific Basis and Engineering Challenges.’’ The 

purpose of the hearing is to explore the science, engineering needs, environmental 

impact(s), price, efficacy, and permanence of select geoengineering proposals.

Witnesses

• Dr. David Keith is the Canada Research Chair in Energy and the Environment at the University of Calgary.

• Dr. Philip Rasch is a Laboratory Fellow of the Atmospheric Sciences and 

Global Change Division and Chief Scientist for Climate Science, Pacific 

Northwest National Laboratory, U.S. Department of Energy.

• Dr. Klaus Lackner is the Ewing Worzel Professor of Geophysics and Chair 

of the Earth and Environmental Engineering Department at Columbia University.

• Dr. Robert Jackson is the Nicholas Chair of Global Environmental Change 

and a professor of Biology at Duke University.

Background 

This hearing is the second of a three-part series on geoengineering. On November 

5, 2009 the Full Committee held the first hearing in the series, entitled 

‘‘Geoengineering: Assessing the Implications of Large-Scale Climate Intervention.’’ 

This Subcommittee hearing will examine the scientific basis and engineering challenges of geoengineering. In the spring of 2010 the Committee will hold the final 

hearing in this series in which issues of governance will be discussed. This series 

of hearings serves to create the foundation for an informed and open dialogue on 

the science and engineering of geoengineering. 

As discussed in the first hearing, strategies for geoengineering typically fall into 

two major categories: Solar Radiation Management and Carbon Dioxide Removal 

(hereafter SRM and CDR, respectively). The objective of Solar Radiation Management (SRM) methods is to reflect a portion of the sun’s radiation back into space, 

thereby reducing the amount of solar radiation trapped in Earth’s atmosphere and 

stabilizing its energy balance. Methodologies for SRM include: installing reflective 

surfaces in space; and increasing reflectivity, or albedo 1 of natural surfaces, built 

structures, and the atmosphere. To balance the impacts of increased atmospheric 

carbon levels, most SRM proposals recommend a goal of 1–2% reduction of absorbed 

solar radiation from current levels. Carbon Dioxide Removal (CDR) methods propose 

to reduce excess CO2 concentrations by capturing, storing, or consuming carbon directly from air, as compared to direct capture from power plant flue gas and storage 

as a gas. CDR proposals typically include such methods as carbon sequestration in 

biomass and soils, ocean fertilization, modified ocean circulation, non-traditional 

carbon capture and sequestration in geologic formations, and distributing mined 

minerals over agricultural soils, among others. 
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2 An increase in ocean cloud cover to 37.5–50% of ocean surface area. 3Groisman PY (1992)

4 Novim (2009) 

Geoengineering Strategies

Atmospheric solar radiation management (SRM) 

One approach to atmospheric SRM is known as ‘marine cloud whitening’ in which 

a fine spray of particles, typically via droplets of salt water, would be injected into 

the troposphere (the lowest level of our atmosphere) to increase the number of 

cloud-condensation nuclei and encourage greater low level cloud formation. The objective is to increase the albedo of existing clouds over the oceans, thus reflecting 

more sunlight into the atmosphere before it reaches Earth. To achieve the necessary 

radiative forcing to stabilize global temperatures, cloud cover would need to increase 

50–100% from current levels.2

Stratospheric sulfate injection is another atmospheric SRM approach.. The objective is to mimic the large quantity of sulfuric emissions and the consequent albedo 

increase that a volcanic eruption would naturally create. For example, the 1991 

eruption of Mt. Pinatubo in the Philippines is thought to have caused a 1–2 year 

decrease in the average global temperature by ∼0.5° C by increasing global albedo.3

To accomplish this effect via stratospheric sulfate injections, a spray of sulfate particles would be injected into the stratosphere, which is between six and 30 miles 

above the Earth’s surface. This proposal typically garners the most attention among 

geoengineering’s scientific community. 

Drawbacks and challenges 

Both atmospheric SRM approaches described here could be quickly deployed at a 

relatively low cost and shut down if necessary; however, both approaches require 

further research and may carry significant unintended consequences for ocean ecosystems, agriculture, and the built environment. 

Marine cloud whitening deployment strategies could include aerosol distribution 

from a large fleet of ships, unmanned radio-controlled ocean vessels, or aircraft. 

Further research is needed to optimize variables such as droplet size and concentration, cloud longevity, and the necessary increase in cloud cover to achieve desired 

results. The material itself (i.e. salt water) would be inexpensive for marine cloud 

whitening as it is abundant, and environmental impacts may be limited and somewhat predictable. However, it has been noted that marine cloud whitening activities 

could cause changes in local weather patterns, and deployment might be very energy-intensive. 

A variety of deployment methods have been suggested for stratospheric sulfate injections, including sprays from aircraft, land-based guns, rockets, manmade chimneys, and aerial balloons.4 Environmental impacts from sulfate injection could occur 

because the sulfate materials would eventually fall from the stratosphere into the 

troposphere and ‘‘rain out’’ onto the land and ocean. This would contribute to ocean 

acidification and could negatively impact crop soils and built structures. 

The SRM strategies discussed here would be long term investments that must be 

carefully planned and continually maintained in order to achieve their goals and 

avoid rapid climatic changes. Presumably, greenhouse gas levels could continuously 

rise while such SRM strategies were deployed. Therefore, in the case of an interruption or termination in service, the actual impact(s) of increased greenhouse gas concentrations would be felt, i.e., the effects of SRM would be quickly negated. This 

would present great risk to human populations and natural ecosystems. Apart from 

these effects, stratospheric injections and marine cloud whitening also run the risk 

of creating localized impacts on regional climates throughout their deployment. In 

addition, the decrease in sunlight over the oceans due to marine cloud whitening 

could affect precipitation patterns and regional ocean ecosystem function. Furthermore, as with other geoengineering ideas, these SRM approaches are criticized for 

drawing attention and resources away from climate change mitigation and CO2 reduction efforts.

Terrestrial-based biological approaches (SRM and CDR) 

The terrestrial-based biological approaches to geoengineering discussed here include vegetative land cover and forestry methods (e.g., the biological sequestration 

of carbon, CDR strategies, and increasing the albedo of terrestrial plants, an SRM 

strategy). These strategies are at different stages of development and deployment, 
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5The Reduced Emissions Deforestation and Degradation (REDD) carbon trading concept provides a starting point for this discussion. The REDD program employs market mechanisms to 

compensate communities in developing countries to protect local forests as an alternative income 

mechanism to logging or farming the same land. 6 Research suggests that vegetative land cover in the form of crops and grasslands can impact 

climate by increasing local albedo by up to 0.25 (on a 0–1 point scale) and thus reflect more light 

into the atmosphere. 7The technology exists, but to deploy it on a commercial scale across the globe could take a 

decade or more. 8 Biochar is charcoal created by the heating of biomass, trees and agriculture waste, in the absence of air, i.e. pyrolysis. 9 Biomass could consist of trees and agricultural wastes. 

10Laird (2008) 11 Not only do biochar-enriched soils contain more carbon, 150gC/kg compared to 20–30gC/

kg in surrounding soils, but biochar-enriched soils are, on average, more than twice as deep as 

surrounding soils. Therefore, the total carbon stored in these soils can be one order of magnitude 

higher than adjacent soils (Winsley 2007). 12Soils also plateau in their ability to sequester CO2. 

with carbon sequestration in forest ecosystems 5 likely to be the most effective in 

the near-term. 

Increasing albedo and carbon sequestration potential in forests, grasslands, and 

croplands 

The ability of forests and other vegetative systems such as grasslands and croplands to store CO2 and to reflect solar radiation is crucial to climate change mitigation efforts. Certain geoengineering strategies propose to leverage these properties 

through massive-scale planting of more reflective or CO2-absorbent vegetation. In 

traditional, terrestrial-based biological carbon sequestration, CO2 is absorbed by 

trees and plants and it is stored in the tree trunks, branches, foliage, roots, and 

soils. Geoengineers propose to alter the ability of the plants and trees to sequester 

carbon or to reflect light 6 using non-native species and techniques from traditional 

plant breeding and genetic engineering. The basic processes of photosynthesis and 

light reflection would still occur, but geoengineers would either increase the carbon 

absorption and reflective capacities of existing vegetation, or introduce non-native 

species with such increased capacity(s). Deployment of these land-cover systems 

would be both systematic and massive to achieve the desired effect(s). 

There are a number of advantages of these approaches. Development and implementation is relatively low cost and the global infrastructure required to create and 

propagate similar traits in crops and grasses through to large-scale cultivation already exists.7 There are fewer potential issues concerning irreversibility than other 

proposed geoengineering schemes. And, the climate impacts are inherently focused 

in the regions that are most important to food production and to population centers, 

thus providing more directed benefits even when applied globally. Maintaining the 

technology is also less of a problem as crops are replanted annually; however, to 

maintain the mitigation benefit, high albedo varietals must be continually planted 

and mature forests must be maintained. 

Biochar 

Biochar 8 may have potential as an efficient method of atmospheric carbon removal (via plant growth) for storage in soil. Biomass 9 is converted to both biochar 

(solid) and a bio-oil (liquid) by heating it in the absence of air. The bio-oil can be 

converted to a biofuel after a costly conversion process, and the biochar can serve 

as bio-sequester (i.e. atmospheric carbon capture and storage). Biochar, is a stable 

charcoal-solid that is rich in carbon content, and thus can potentially be used to lock 

globally significant amounts of carbon in the soil.10 Unlike typical CO2 capture 

methods which typically require large amounts of oxygen and require energy for injection, the biochar process breaks the carbon dioxide cycle, releasing oxygen, and 

removing carbon from the atmosphere and sequestering it in the soil for possibly 

hundreds to thousands of years.11

Drawbacks and challenges 

The biological systems discussed here present challenges to the development of effective deployment, accounting, and verification systems for these terrestrial-based 

approaches to geoengineering. For example, the climate benefits of sequestration 

practices can be partially or completely reversed because these resources are subject 

to natural decay, disturbances, and harvests, which could result in the sudden or 

gradual release the carbon back to the atmosphere. Forests plateau 12 in their ability to reflect light and absorb CO2 as they mature, and they release CO2 as they 
141

13Lehmann, Gaunt and Rondon (2006) 14Lal et al. (1999) 15West and Post (2002) 16Dubey et al. (2002) 17Kelemen and Matter (2008)

decay; therefore, their utilization as geoengineering strategies would require careful 

monitoring and accounting of CO2 storage over time as these systems do not provide 

long-term storage stability. These systems would also need to be maintained even 

after saturation to prevent subsequent losses of carbon back to the atmosphere. This 

would also be the case for management of soils.13 14 15 Addressing these challenges 

is important if sequestration benefits are to be compared to other approaches. 

Sophisticated and verifiable carbon accounting strategies are needed across the 

board to optimize carbon-sensitive land uses at different climates and geographies. 

Existing statistical sampling, models and remote sensing tools can estimate carbon 

sequestration and emission sources at the global, national, and local scales. However, complex spatial-temporal models would be required for each technique described here. For example, estimating changes in soil carbon over time is generally 

more challenging than those for forests due to the high degree of variability of soil 

organic matter—even within small geographic scales like a corn field—and because 

changes in soil carbon may be small compared to the total amount of soil carbon. 

And, it is not presently clear whether there would be greater carbon savings by 

planting trees and then converting those trees into biochar or planting trees and 

allowing them to grow, thereby sequestering carbon in both the soil and in the plant 

material. 

Tradeoffs between immediate climate objectives and environmental quality may 

be necessary with these techniques. If nitrogen-based fertilizers are applied to crops 

to increase yields for biological sequestration methods, the benefit would be partially 

or completely offset by increased emissions of N2O. The installation of non-native 

or genetically engineered species could be associated with additional environmental 

disruption such counteractive changes in reflectivity. For example, a large scale 

afforestation initiative over snow or highly reflective grasslands would increase carbon consumption but greatly decrease local albedo. Similarly, genetic modification 

of crops to increase their albedo could reduce their carbon uptake. Lastly, these 

techniques are likely to replace diverse ecosystems with single-species timber or 

grass plantations to generate greater carbon accumulation at the cost of biodiversity.

Non-traditional carbon capture and sequestration or conversion 

Non-traditional carbon capture and sequestration (i.e. conversion) strategies 

would utilize geological systems to capture carbon. First carbon would be captured 

by exposing it to chemical adsorbents such as calcium hydroxide (CaCO3, zeolites, 

silicates, amines, and magnesium hydroxide (Mg(OH)2).16 Then, heat or agitation 

would be used to separate the carbon from the adsorbent. The carbon can then be 

stored in a geologic receptacle or it would be stored as a new chemical compound 

in a liquid or solid formation. 

Most geologic carbon removal strategies can be categorized as in situ or ex situ. 

Ex situ carbonation requires the sourcing and transportation of materials that react 

with carbon to the source of output (e.g., the smokestack). The energy input may 

be quite high because the carbon absorbent must be ground up to allow for a sufficient rate of carbon absorption. Air capture is a key component to the geologic carbon sequestration and geochemical weathering of carbon. In this process, a carbonadsorbent chemical, such as calcium hydroxide, binds to carbon and separates it 

from the ambient air. The adsorbent chemical is then heated, the bound CO2 is released, and a pure CO2 stream is produced. Air capture differs from traditional carbon capture on power plants and other high-intensity carbon emitters in that it is 

a distributed approach to capture (as many of the main sources of carbon are actually a collection of distributed entities, e.g. vehicles and buildings). 

Alternatively, in situ carbonation injects carbon into geologic formations suited to 

the mineralization of carbon.17 The injected material is then left in the formation 

to carbonize at a more natural rate. Carbon storage in a liquid or solid represents 

a more permanent option for carbon management and can be thought of as the mere 

stimulation of naturally occurring processes that take place over thousands of years 

instead of months. It would potentially require less stringent regulatory and liability 

frameworks than traditional carbon storage in a gaseous form. This could make deployment costs more manageable per unit than traditional carbon capture and storage. 
142

Challenges and drawbacks 

The scale required for deployment of non-traditional carbon capture and sequestration methods present challenges to their eventual use. Geological capture and 

storage at a geoengineering scale would represent an immense investment, requiring hundreds or thousands of units and immense land formations suitable for storage. In addition, most suggested geological sequestration strategies require a high 

input of heat or pressure, either to release the carbon from its adsorbents or to 

speed the necessary reactions for solid storage, and thus are energy burdens for the 

deployment of this technology. 

Ambient air is comprised of 0.04% carbon, and the slip streams of exhaust from 

coal fired power plants are approximately 15%; therefore, the amount of carbon 

gathered per unit of air processed would be far lower. In addition to issues of scale, 

in situ storage material may remain as a gas and be released after a period of time, 

which leads to additional monitoring and verification needs.

Other Strategies 

Several geoengineering strategies were not emphasized in this hearing due to projected environmental impacts and project feasibility. Several of these techniques are 

detailed below.

Enhanced weathering techniques—Silicate minerals would be sourced, ground, and 

distributed over agricultural soils to form carbonates. This category of in situ

carbonation works in the same manner as the non-traditional carbon consumption 

strategies discussed above. The actual mineral distribution could be performed at 

a relatively low direct cost; however, the mining activities would require sizable energy inputs. In addition, introducing large quantities of chemicals to a landmass 

could incur significant changes, both predictable and unpredictable, to the entire 

ecosystem.

Chemical ocean fertilization—Similar to enhanced weathering in terrestrial systems, this strategy calls for the distribution of ground minerals over the oceans. 

Iron, silicates, phosphorus, nitrogen, calcium hydroxide and/or limestone could enhance natural chemical processes that consume carbon, such as photosynthesis in 

phytoplankton. Mining and environmental impacts are major challenges. Iron is the 

most popular candidate chemical for this strategy as it would require the smallest 

quantity to significantly lower carbon concentrations.

Oceanic upwelling and downwelling—Naturally occurring ocean circulation would 

be accelerated in order to transfer atmospheric greenhouse gases to the deep sea. 

Atmospheric carbon is absorbed by the ocean at the air-water interface, and it is 

largely stored in the top third of the water column. This approach would use vertical 

pipes to transfer the carbon rich surface waters to the deep ocean for storage. It 

would likely require massive engineering efforts and could significantly alter the 

ocean’s natural carbon cycle and circulation systems.

White roofs and surfaces—Painting the roofs of urban structures and pavements 

in the urban environment white would increase their albedo by 15–25%. A white 

roofs program would need global implementation to achieve a meaningful impact on 

radiative forcing, incurring great costs and logistical challenges; however, white 

roofs can help mitigate the urban heat island problem, which plagues metropolises 

like Tokyo and New York City.

Desert reflectors—Metallic and other reflective materials would be used to cover 

largely underused desert areas, which account for 2% of the earth’s surface to reflect 

sunlight. This approach could have large detrimental impacts on local ecosystems 

and precipitation patterns. Preliminary cost estimates are in the high billions or 

trillions of dollars.

Space-based reflective surfaces—A large satellite or an array of several small satellites with mirrors or sunshades would be placed in orbit or at the sun-earth Lagrange (L l) point to reflect some percentage of sun radiation. Preliminary cost estimates for this strategy are usually in the trillions of dollars.

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1Some discussion was held prior to the formal opening of this hearing. For a transcript of 

these comments, see Appendix. 

Chairman BAIRD. I will call the hearing to order.1

As I mentioned earlier, I have already introduced our witnesses, 

and this is a hearing on geoengineering. As we deal with the issues 

of overheating of our planet and acidification of the ocean, this is 

one option for possibly mitigating the impacts, part of a series of 

hearings and an effort initiated by our Chair, Mr. Gordon. 

[The prepared statement of Chairman Baird follows:]

PREPARED STATEMENT OF CHAIRMAN BRIAN BAIRD

Good morning. I want to welcome everyone to today’s hearing discussing the scientific and technological premises underlying various proposals for geoengineering. 

Geoengineering is a term that has come to define a range of often controversial 

strategies to deliberately alter the Earth’s climate systems for the purpose of counteracting climate change—presumably through reflection of sunlight or absorption 

of CO2 from the air. 

Make no mistake, despite the sometimes far-fetched proposals, this is not a subject that should be taken lightly. As Chairman Gordon has also made clear: 

Geoengineering has been proposed as, and it can only be responsibly discussed as 

a last-ditch measure in the case that traditional carbon mitigation efforts prove ineffective on their own. Even then, a tremendous amount of research is required to 

know what strategies may be worth deploying. 

The concentration of greenhouse gases in the atmosphere is already driving great 

changes in the Earth’s climate. 

The long-term consequences of climate change will become especially threatening, 

and some of these consequences are already being felt. 

For example, oceans naturally absorb atmospheric carbon through the air-water 

interface. As the concentration of greenhouse gases has increased in the atmosphere 

so has the absorption of carbon by the oceans. On the surface this is good because 

it helps to mitigate climate change; however, below the ocean’s surface the excessive 

absorption of carbon is changing the chemistry of the ocean—it is creating ocean 

acidification. 

The effects of ocean acidification will span the ocean food web which will affect 

our fishermen, coastal communities, and our national and global economies. 

Today’s hearing is not about ocean acidification per se, but it is about controversial methods to reduce or mitigate the causes and effects of climate change through 

geoengineering. 

Without question, our first priority is to reduce the production of global greenhouse gas emissions. 

However, as I said, if such reductions achieve too little, too late, there may be 

a need to consider a plan B—to utilize methodologies to counteract the climatic effects of greenhouse gas emissions by ‘geoengineering’. 

Many proposals for geoengineering have already been made. Some may have potential, some sound downright scary, and they all carry levels of uncertainty, hazards, and risks that could outweigh their intended benefit. 

Furthermore, the technologies proposed for deployment of many of these 

geoengineering techniques are very young or non-existent, and there are major uncertainties regarding their effectiveness, environmental impacts, and economic costs. 

For example, I am especially interested in discussing the potential for the solar 

radiation management techniques to exacerbate ocean acidification. 

The implications of geoengineering are decidedly global in scope, but 

geoengineering has the potential to be undertaken in a unilateral fashion, without 

consensus or regard for the well-being of other nations. 

Therefore, an open, public dialogue is needed in the face of such hazards, risks, 

and uncertainties. As you may recall this hearing is the second of a three-part series 

on geoengineering. 

On November 5, 2009, the Full Committee held the first hearing in the series, 

entitled ‘‘Geoengineering: Assessing the Implications of Large-Scale Climate Intervention.’’

Today’s Subcommittee hearing will examine the scientific basis and engineering 

challenges of geoengineering. 
145

This series of hearings serves to create the foundation for an informed and open 

dialogue on the science of geoengineering, and should in no way be regarded as supportive of deployment of geoengineering. 

With that I turn it over to the distinguished Ranking Member, Mr. Inglis. 

Chairman BAIRD. I thank the Ranking Member for being here, 

and recognize him if he has any opening remarks. 

Mr. INGLIS. I don’t, Mr. Chairman, and I will submit them for 

the record. 

[The prepared statement of Mr. Inglis follows:]

PREPARED STATEMENT OF REPRESENTATIVE BOB INGLIS

Good morning, and thank you for holding this hearing, Mr. Chairman. I look forward to discussing the scientific and engineering challenges related to 

geoengineering. 

Last November, the full committee began our examination of geoengineering as 

a strategy to minimize the impacts of a warming climate. What we heard was theoretically promising: geoengineering may prove to be a low-cost intervention to buy 

us time to reduce our greenhouse gas emissions and limit our impact on the global 

climate system. 

Still, we face considerable uncertainty. Dr. Rasch appropriately describes 

geoengineering as a ‘‘gamble’’ in his testimony. is this a gamble worth trying? At 

this hearing, I hope to hear what steps we need to take to increase our understanding of geoengineering technologies and come one step closer to determining 

whether this is a viable option. 

In particular, I hope that the witnesses will discuss what technologies, techniques, 

and capabilities must be developed to study and deploy geoengineering options, and 

what level of financial investment is required for these developments. I also hope 

the witnesses will discuss the gaps in our understanding of the climate system that 

may limit our ability to justify such large-scale intervention, and which alternatives 

may minimize further changes to the climate, resource cycles, or global ecology. 

We also need to decide whether investments in geoengineering are worthwhile. 

There are a number of ecological, economic, and political uncertainties that also 

need to be addressed before these interventionist strategies are implemented. Moreover, there is a significant ethical question involved in deploying large-scale 

geoengineering techniques to forcibly change the climate in an effort to undo the 

damage we have already done. I hope to address these questions in a future hearing. 

Again, thank you for holding this important hearing, Mr. Chairman. I look forward to hearing from the witnesses and I yield back the balance of my time.

Chairman BAIRD. Thank you, and I will submit my opening remarks for the record. 

With that, we will proceed. Each witness will have five minutes 

to proceed. Then if we have time, we will follow up with questions. 

If not, we will take a break for votes. 

Dr. Keith, please. 

STATEMENTS OF DR. DAVID KEITH, CANADA RESEARCH 

CHAIR IN ENERGY AND THE ENVIRONMENT, DIRECTOR, 

ISEEE ENERGY AND ENVIRONMENTAL SYSTEMS GROUP, 

UNIVERSITY OF CALGARY 

Dr. KEITH. Chairman Baird, Committee Members, thank you 

very much for having me here today. 

We must make deep cuts in global emissions if we are going to 

manage the risks of climate change. Emissions reductions are necessary, but they are not necessarily sufficient. This is because even 

if we halt all emissions instantly today, which is not going to happen, the climate risks they pose would persist for millennia. Also, 

the climate’s response to the amount of CO2 we put in the air is 

highly uncertain. We could get lucky and see small amounts of climate change, or we could be unlucky. Risk management is the 
146

heart of climate policy, so a small risk of catastrophic impact exists 

even with today’s carbon burden, and that risk grows with each ton 

of new emissions. So because risk management is central, we must 

hope for the best while laying plans to navigate the worst. 

Geoengineering describes two distinct concepts. Carbon dioxide 

removal, CDR, is a set of tools for removing carbon dioxide from 

the atmosphere, while solar radiation management, SRM, would 

reduce the earth’s absorption of solar energy, cooling the planet by 

adding sulfur aerosols to the upper atmosphere or by adding sea 

salt aerosols to whiten marine clouds. SRM and CDR—forgive my 

acronyms—do different things, entirely different things. SRM is 

cheap and can act quickly to cool the planet, but it introduces novel 

environmental and security risks, and it can at best only partially 

mask the impacts of CO2 in the air. The low price tag is very attractive but it raises the risks of unilateral action and a facile 

cheerleading that promotes exclusive reliance on SRM. 

In concert with emissions cuts, CDR can reduce the carbon burden in the atmosphere, a kind of global climate remediation. We 

need this capability. Unless we can remove CO2 from the air faster 

than nature does, we will, we are, consigning the earth to a warmer future for millennia or a sustained and risky program of solar 

radiation management. 

Carbon removal can only make a difference if we capture carbon 

by the gigaton. The sheer scale of the carbon challenge means that 

just like emissions cuts, CDR will always be much more expensive 

and much slower acting than SRM. 

SRM and CDR—again, forgive the acronyms—each provide a 

means to manage climate risk, but they are wholly distinct with respect to the science and technology required to deploy and test 

them, with respect to their costs and environmental risks, and with 

respect to the challenges they pose for public policy and governance 

regulation. Because these technologies have little in common, I suggest that we will have a better chance to craft sensible policy if we 

separate them almost entirely in the policy process. 

In the spirit of disclosure, I offer a few comments about my own 

work. Along with my academic work, I run a startup company, Carbon Engineering, that seeks to develop large-scale industrial technologies for capturing CO2 from the air, a form of CDR. Professor 

Lackner will say more about this later. I am thrilled to work on 

this technology. It has a shot, however small, at providing a tool 

to manage one of the greatest environmental threats. I will be 

happy to answer questions about this and other CDR technologies 

but I will focus my remarks on SRM because I believe that is 

where there is the most urgent need for government action. 

Because of the serious concerns raised by the enormous leverage 

SRM grants us over the global climate, I think it is crucial that development of these technologies be managed in a way that is as 

transparent as possible. I therefore do no commercial or proprietary work on SRM. 

In my written comments, I offer some thoughts about the specific 

kinds of research that are needed, the funding, the agencies that 

might be appropriate or might not, the scale of the research program. One thing I will say here is that we don’t want to start too 
147

fast. Research programs can be killed by getting too much money 

too quickly. 

The idea of deliberately manipulating the earth’s energy balance 

to offset human-driven climate change strikes many as dangerous 

hubris. Solar engineering is like chemotherapy: no one wants it. It 

is far better to avoid carcinogens but we all want the ability to do 

chemo and to understand its risks should we find ourselves with 

dangerous cancer. The primary argument against doing SRM research is fear that it will sap our will to cut emissions. I share this 

view. Yet I believe that the risks of not doing research outweigh 

the risks of doing it. SRM may be the only means to fend off the 

risk of rapid and high-consequence climate impacts. Furthermore, 

there are environmental and geopolitical risks posed by the potential of unilateral deployment of SRM by a small or large state acting alone which can best be managed by developing widely shared 

knowledge, risk assessment and norms of governance. I don’t mean 

one big U.N.-style government system, I just mean some understanding, however it works, of how we manage this thermostat for 

the planet. 

It is a healthy sign that a common first response to 

geoengineering is revulsion. It suggests we have learned something 

from past instances of techno-optimism and subsequent failures, 

but we must not overinterpret past experience. Responsible management of climate risk requires sharp emissions cuts and cleareyed research on SRM linked with the development of shared tools 

for managing it. The two are not in opposition. They are not dichotomies. We are currently doing very little on either, cutting 

emissions or this, and we urgently need action on both. Thank you. 

[The prepared statement of Dr. Keith follows:]

PREPARED STATEMENT OF DAVID KEITH

Learning to manage sunlight: Research needs for Solar Radiation Management

Two kinds of geoengineering 

Geoengineering describes two distinct concepts. Carbon Dioxide Removal (CDR) 

describes a set of tools for removing carbon dioxide from the atmosphere, while 

Solar Radiation Management (SRM) would reduce the Earth’s absorption of solar 

energy, cooling the planet by, for example, adding sulfur aerosols to the upper atmosphere or adding sea salt aerosols to increase the lifetime and reflectivity of lowaltitude clouds. 

We must make deep cuts in global emissions of carbon dioxide to manage the 

risks of climate change. While emissions reductions are necessary, they are not necessarily sufficient. Emission cuts alone may be insufficient because even if we could 

halt all carbon emissions today, the climate risks they pose would persist for millennia—by some measures, the climate impact of carbon emissions persists longer 

than nuclear waste. Moreover, the climatic response to elevated carbon dioxide concentration is uncertain, so a small risk of catastrophic impacts exists even at today’s 

concentration. 

Technologies for decarbonizing the energy system, from solar or nuclear power to 

the capture of CO2 from the flue gases of coal-fired power plants, can cut emissions—allowing us to limit our future commitment to warming—but they cannot reduce the climate risk posed by the carbon we have already added to the air, and 

that risk grows as each ton of emissions drive up the atmospheric carbon burden. 

Risk management is at the heart of climate policy: planning our response around 

our current estimate of the most likely outcome is reckless. We must hope for the 

best while laying plans to navigate the worst. 

SRM and CDR do different things. SRM is cheap and can act quickly to cool the 

planet, but it introduces novel environmental and security risks and can—at 

best—only partially mask the environmental impacts of elevated carbon dioxide. 
148

In concert with emissions cuts, CDR technologies can reduce the carbon burden 

in the atmosphere; one might call it global climate remediation. We need a means 

to reduce atmospheric CO2 concentrations in order to manage the long-run risks of 

climate change. Unless we can remove CO2 from the air faster than nature does, 

we will consign the earth to a warmer future for millennia or commit ourselves to 

the risks of sustained SRM. 

But, carbon removal can only make a difference if we capture carbon by the 

gigaton. The shear scale of the carbon challenge means that CDR will always be 

relatively slow and expensive. 

SRM and CDR each provide a means to manage climate risks; they are, however, 

wholly distinct with respect to

the science and technology required to develop, test and deploy them;

their costs and environmental risks; and,

the challenges they pose for public policy and governance.

Because these technologies have little in common, I suggest that we will have a 

better chance to craft sensible policy if we treat them separately. 

In the spirit of disclosure, I offer a few comments about my own work. I run Carbon Engineering, a startup company that aims to develop industrial scale technologies for capturing CO2 from the air. I will be happy to answer questions about 

these technologies, but I will focus my remarks on SRM because I believe that is 

where there is the most urgent need for action that links the development of a research program to progress on learning how to manage this potentially dangerous 

technology. 

Because of the serious and legitimate concerns raised by the enormous leverage 

SRM technologies grant us over the global climate, I think it is crucial that development of these technologies be managed in a way that is as transparent as possible. 

I therefore do no commercial or proprietary work on SRM. 

The primary argument against research on SRM is fear that it will reduce the 

political will to lower greenhouse gas emissions. I believe that the risks of not doing 

research outweigh the risks of doing it. Solar-radiation management may be the 

only response that can fend off unlikely but rapid and high-consequence climate impacts. Further, there are environmental and geopolitical risks posed by the potential 

of unilateral deployment of SRM, which can best be managed by developing widelyshared knowledge, risk assessment, and norms of governance. 

The idea of deliberately manipulating the Earth’s energy balance to offset humandriven climate change strikes many as dangerous hubris. It is a healthy sign that 

a common first response to geoengineering is revulsion. It suggests we have learned 

something from past instances of over-eager technological optimism and subsequent 

failures. But we must also avoid over-interpreting this past experience. Responsible 

management of climate risks requires sharp emissions cuts and clear-eyed research 

and assessment of SRM capability. The two are not in opposition. We are currently 

doing neither; action is urgently needed on both.

An overview of solar radiation management 

SRM has three essential characteristics: it is cheap, fast, and imperfect. Long-established estimates show that SRM could offset this century’s global-average temperature rise a few hundred times more cheaply than achieving the same cooling 

by emission cuts. This is because such a tiny mass is required: a few grams of sulfate particles in the stratosphere can offset the radiative forcing of a ton of atmospheric carbon dioxide. At a few $1000 a ton for aerosol delivery to the stratosphere 

that adds up to a figure in the order of $10 billion dollars per year to provide a 

cooling that—however crudely—counteracts the heating from a doubling of atmospheric carbon dioxide. 

This low price tag is attractive, but raises the risks of single groups acting alone 

and of facile cheerleading that promotes exclusive reliance on SRM. 

SRM can alter the global climate within months—as shown by the 1991 eruption 

of Mt. Pinatubo, which cooled the globe about 0.5° C in less than a year. In contrast, 

because of the carbon cycle’s inertia, even a massive program of emission cuts or 

carbon dioxide removal will take many decades to discernibly slow global warming. 

A world cooled by managing sunlight will not be the same as one cooled by lowering emissions. An SRM-cooled world would have less precipitation and less evaporation. Some areas would be more protected from temperature changes than others, 

creating local winners and losers. SRM could weaken monsoon rains and winds. It 

would not combat ocean acidification or other carbon dioxide-driven ecosystem 

changes and would introduce other environmental risks such as delaying the recov-
149

ery of the ozone hole. Initial studies suggest that known risks are small, but the 

possibility of unanticipated risks remains a serious underlying concern. 

Cheap, fast and imperfect: each of these essential characteristics has profound implications for public policy.

Because SRM is imperfect, it cannot replace emissions cuts. If we let emissions grow and rely solely on SRM to limit warming, these problems will eventually 

grow to pose risks comparable to the risks of uncontrolled emissions. 

Because SRM is cheap, even a small county could act alone, a fact that poses 

hard and novel challenges for international security. 

Finally, because SRM appears to be the only fast-acting method of slowing 

global warming it may be a powerful tool to manage the risks of unexpectedly dangerous climate outcomes.

Towards Solar Radiation Management research plan 

The capacity to implement SRM cannot simply be assumed. It must be developed, 

tested, and assessed. Research to date has largely consisted of a handful of climate 

model studies, using very simple parameterization of aerosol microphysics. More 

complex models of aerosol physics need to be developed and linked to global climate 

models. Field tests will be needed, such as experiments generating and tracking 

stratospheric aerosols to block sunlight and dispersing sea-salt aerosols to brighten 

marine clouds. Decades of upper atmosphere research has produced a mass of relevant science. But, except for a recent ill-conceived Russian test, there have been 

no field tests of SRM. 

There has been no dedicated government research funding available for SRM anywhere in the world; though, a few programs for have begun in Europe in the past 

few months. 

The environmental hazards of SRM cannot be assessed without knowing the specific techniques that might be used, and it is impossible to identify and develop techniques without field testing. Such tests can be small: tonnes not megatonnes. 

It is widely assumed, for example, that a suitable distribution of stratospheric sulfate aerosols can be produced by releasing SO2 in the stratosphere, but new simulations of aerosol micro-physics suggest the resultant aerosol size distribution would 

be skewed to large particles that are relatively ineffective. Several aerosol compositions and delivery methods may offer a way around this problem, but choosing between them and assessing their environmental impacts will require small-scale insitu testing. 

To provide a specific example related to my own work, NASA’s ER–2 high-altitude 

research plane might be used to release a ton of sulfuric acid vapor along a 10 km 

plume in the stratosphere, and fly through the plume to assess the formation of aerosol and its sun scattering ability and its impact on ozone chemistry. Such tests 

take a few years to plan and cost a few million dollars. 

An international research budget growing from roughly $10 million to $1 billion 

annually over this decade would likely be sufficient to build the capability to deploy 

SRM and greatly improve understanding of its risks. 

It is important to start slowly. Research programs can fail if they get too much 

money too quickly. Given the limited scientific community now knowledgeable about 

SRM, a very rapid buildup of research funding might result in a lot of ill-conceived 

projects being funded and, given the inherently controversial nature of the technology, the result might be a backlash that effectively ends systematic research. 

The U.S. will need an interagency research program, because no single agency has 

the right combination of abilities to manage the whole program. For example, NSF’s 

processes for transparent peer-review and investigator driven funding will be important in effectively supporting the diversity of critical analysis that is necessary on 

such an inherently controversial topic. But NSF is perhaps less suited to manage 

the larger mission oriented programs that link technology development and science. 

NASA has some institutional history and abilities that may be particularly relevant to stratospheric SRM. The high-speed research program, for example, linked 

scientific efforts to understand the impacts a supersonic transport fleet on the ozone 

layer with technology development aimed to minimize those impacts. The management and research assets used in this program could serve as the foundation of a 

program to develop and test technologies for delivering stratospheric aerosols. But 

NASA is less suited to fostering diverse early-stage science. 

DOE’s Office of Science has a record managing large programs and DOE has a 

relevant track record with its Atmospheric Radiation Measurement (ARM) program. 

But SRM is not at its core an energy problem and there will be difficulties fitting 

it into the DOE structure. 
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Finally, the inherently controversial nature of SRM research makes it particularly 

important that it not be entrusted exclusively to either its proponents or its adversaries. The development of an interagency program may help to foster the necessary 

diversity. Indeed, there may be value in a ‘‘blue team/red team’’ approach, as sometimes used for military preparedness planning. One team is charged to make an approach as effective and low-risk as possible, while the other works to identify all 

the ways it can fail. Anticipating the conditions of urgency, even panic, that might 

attend a future decision to deploy SRM, such an adversarial approach may increase 

the quality and utility of information available in time to aid future decision-makers.

Concluding thoughts 

Although risk of climate emergencies may motivate SRM research, it would be 

reckless to conduct the first large-scale SRM tests in an emergency. Instead, experiments should expand gradually to scales big enough to produce barely detectable climate effects and reveal unexpected problems, yet small enough to limit resultant 

risks. Our ability to detect the climatic response to SRM grows with the test’s duration, so starting sooner makes the scale of experiment needed to give detectable results by any future date-say by 2030-smaller. A later start delays when results are 

known, or requires a bigger intervention in order to detect the response. 

Beyond research, building responsibly toward future SRM capability also requires 

surmounting problems of international governance that are hard, and novel. These 

are quite unlike the problems of emissions mitigation, where the main governance 

challenge is motivating contributions to a costly shared goal. For SRM, the main 

problem will be establishing legitimate collective control over an activity that some 

might seek to do unilaterally. Such a unilateral challenge could arise in many forms 

and from many quarters. At one extreme, a state might simply decide that avoiding 

climate-change impacts on its people takes precedence over environmental concerns 

of SRM and begin injecting sulfur into the stratosphere, with no prior risk assessment or international consultation. If this were a small state, it could be quickly 

stopped by great-power intervention. If it were a major state, that might not be possible. 

Alternatively a nation might grow frustrated at the pace of international cooperation and establish a national program of gradually expanding research and field 

tests. This might be linked to a distinguished international advisory board, including leading scientists and retired politicians of global stature. It is plausible that, 

after exhausting other avenues to limit climate risks, such a nation might decide 

to begin a gradual, well-monitored program of SRM deployment, even absent any 

international agreement on its regulation. In this case, one nation—which need not 

be a large and rich industrialized country—would effectively seize the initiative on 

global climate, making it extremely difficult for other powers to restrain it. 

No existing treaty or institution is well suited to SRM governance. Given current 

uncertainties immediate negotiation of a treaty is probably not advisable. Hasty 

pursuit of international regulation would risk locking in commitments that might 

soon be seen as wrong-headed, such as a total ban on research or testing, or burdensome vetting of even innocuous research projects. 

A better approach would be to build international cooperation and norms from the 

bottom up, as knowledge and experience develop—as has occurred in cases as diverse as the development of technical standards for communications technology to 

the landmine treaty which emerged bottom-up from action by NGOs. A first step 

might be a transparent, loosely-coordinated international program supporting research and risk assessments by multiple independent teams. Simultaneously, informal consultations on risk assessment, acceptability, regulation, and governance 

could engage broad groups of experts and stakeholders such as former government 

officials and NGO leaders. Iterative links between emerging governance and ongoing 

scientific and technical research would be the core of this bottom-up approach. 

Opinions about SRM are changing rapidly. Only a few years ago, many scientists 

opposed open discussion of the topic. Many now support model-based research, but 

discussion of field testing of the sort we advocate here is contentious and will likely 

grow more so. The main argument against SRM research is that it would undermine 

already-inadequate resolve to cut emissions. I am keenly aware of this ‘moral hazard’—indeed I introduced the term into the geoengineering literature—but I am 

skeptical that suppressing SRM research would in fact raise commitment to mitigation. Indeed, with the possibility of SRM now widely recognized, failing to subject 

it to serious research and risk assessment may well pose the greater threat to mitigation efforts, by allowing implicit reliance on SRM without critical scrutiny of its 

actual requirements, limitations, and risks. If SRM proves to be unworkable or 
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poses unacceptable risks, the sooner we know the less moral hazard it poses; if it 

is effective, we gain a useful additional tool to limit climate damages.

BIOGRAPHY FOR DAVID KEITH

Professor Keith has worked near the interface between climate science, energy 

technology and public policy for 20 years. His work in technology and policy assessment has centered on the capture and storage of CO2. the technology and implications of global climate engineering, the economics and climatic impacts of large-scale 

wind power and the prospects for hydrogen fuel. As a technologist, David has built 

a high-accuracy infrared spectrometer for NASA’s ER–2 and developed new methods 

for reservoir engineering increase the safety of stored CO2. He now leads a team 

of engineers developing technology to capture of CO2 from ambient air at an industrial scale. 

David took first prize in Canada’s national physics prize exam, he won MIT’s 

prize for excellence in experimental physics, was listed as one of TIME magazine’s 

Heroes of the Environment 2009 and was named Environmental Scientist of the 

Year by Canadian Geographic in 2006. He spent most of his career in the United 

States at Harvard University and Carnegie Mellon University before returning to 

Canada in 2004 to lead a research group in energy and environmental systems at 

the University of Calgary. 

David has served on numerous high-profile advisory panels such as the U.K. 

Royal Society’s geoengineering study, the IPCC, and Canadian ‘blue ribbon’ panels 

and boards. David has addressed technical audiences with articles in Science and 

Nature, he has consulted for national governments, global industry leaders and 

international environmental groups, and has reached the public through venues 

such as the BBC, NPR, CNN and the editorial page of the New York Times. 

Chairman BAIRD. Thank you, Dr. Keith. 

Dr. Rasch. 

STATEMENTS OF DR. PHILIP RASCH, CHIEF SCIENTIST FOR 

CLIMATE SCIENCE, LABORATORY FELLOW, ATMOSPHERIC 

SCIENCES AND GLOBAL CHANGE DIVISION, PACIFIC NORTHWEST NATIONAL LABORATORY 

Dr. RASCH. Thank you, Chairman Baird and the Subcommittee, 

for inviting me today. 

I think I will start by just reminding you of what solar radiation 

management is. Scientists tend to loosely refer to light or heat or 

energy as radiation, and so when we speak of solar radiation management, we really mean managing the amount of sunlight reaching the surface of the earth. If we can reflect a little bit more sunlight back to space, then we will cool the planet. 

Before jumping into some of the scientific issues, I am going to 

speak just for a second on funding issues. If you look at my assessment of funding in the written testimony, you will see that I think 

that the total grants from U.S. agencies today for geoengineering 
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research amounts to about $200,000 a year. If you add in some invisible funding that comes from faculty members or scientists like 

myself donating their time, it might double. If you add in foundation money, it might come to a million dollars a year. If you contrast this with the kind of program like the Apollo program to put 

a man on the moon of $2 billion per year or total up all the climate 

research today of $1 billion per year, then you can see we are currently putting a tiny, tiny amount in, and maybe that is the right 

thing to do. That is really for policymakers like you to help us decide. But if you think it is important to do geoengineering research, 

then it would be very easy to make a big difference with a relatively small amount of money. 

You asked me to talk about the solar radiation management 

techniques known as stratospheric sulfate aerosols and cloud whitening. I have worked in both of these areas. Scientists are interested in these two ideas because we already know they play a role 

in the real world. We see that when volcanoes produce sulfate 

aerosols high in the atmosphere, the planet cools. We see that 

when ships inject aerosols as pollution into clouds, that those 

clouds become whiter and reflect more sunlight—some of those 

clouds do—which should cool the planet a bit. We think we might 

be able to do the same kind of thing deliberately. In climate models 

when we brighten the clouds, we see that the planet cools. When 

we inject an aerosol like volcanoes do, we see that the planet cools. 

That is the good news, but that statement is far too simple. There 

are also undesirable things that happen. We see that even though 

we might make the average temperature of the planet about right, 

the rainfall patterns would change some from today, and some 

places become warmer and some places become cooler. 

So there are going to be winners and losers in this 

geoengineering activity if we were to do it. But nevertheless, as 

David has said, there are reasons why we might consider doing it. 

We know that the models that we are using today are far too simple and incomplete. We know how to do better. There are many 

outstanding unresolved important issues that need to be addressed 

if one wants to understand geoengineering better. I have made 

some suggestions in my written testimony about ways we might 

use funding to strengthen the activity involving computer modeling, technology development, and lab and field research. There 

are a bunch of first-class research scientists and engineers in the 

United States and Europe now working for free in their spare time 

to think about this, but there are some things that take money to 

solve, and a much better job could be done if there was a funded 

program for geoengineering. 

All the work that I have suggested doing essentially comes down 

to focusing on two questions: Can we actually create particles in 

the stratosphere or whiten clouds as we assumed in our first climate studies? We need technology development and we need fundamental research to understand this. 

Then the second part would be: What would be the impact on climate if we did put the particles into the stratosphere or whiten 

clouds? This involves deployment, actually, at some level. I think 

I have to skip over, in the interest of time, my discussions of some 

of the subtleties of the ways we could focus on the cloud whitening 
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or the stratospheric aerosols, but I would be glad to take questions 

about it. 

You also asked me to address deployment issues. I feel very 

strongly we are not ready for deployment, if by deployment you 

mean trying to affect the climate. There are too many things that 

haven’t been looked at yet, but there is a lot we can do with 

fieldwork that will help us understand geoengineering but won’t 

change the climate. For the cloud whitening strategy, field and 

modeling studies would help us understand a critical feature of the 

climate system called the aerosol indirect effect, which is really 

critical for understanding climate change more generally as well. I 

don’t have the time to talk to you about this now but I would love 

to address it if you ask me questions. 

I think that if we managed to tighten up our work to the point 

that we think a geoengineering strategy looks viable, it would probably require a Manhattan Project, looking at it with a much larger 

group of stakeholders, checking the science, searching for flaws in 

our initial work and worrying about issues far beyond the scope of 

physical scientists. 

Thanks for listening to me and I am happy to take questions. 

[The prepared statement of Dr. Rasch follows:]

PREPARED STATEMENT OF PHILIP RASCH

I would like to thank the committee for the invitation to provide testimony at this 

hearing. I am aware that this is the second of three hearings on geoengineering, 

and that you have already been introduced to many of the concepts behind 

geoengineering at your previous hearing. A number of important documents were 

submitted during the previous hearing. I will not submit any more beyond my own 

testimony during this hearing, but I do refer to a few more scientific papers that 

I think are relevant (listed in the references at the end). I have attempted to strike 

a balance between repeating some of the information covered in the last hearing to 

provide continuity, and new material. 

There are two classes of geoengineering (the intentional modification of the 

Earth’s Climate) being discussed in the scientific community and by the congressional committee: 1) Approaches designed to draw down the concentration of Greenhouse Gases, to reduce Global Warming; and 2) ‘‘Solar Radiation Management’’. You 

asked me to focus on Solar Radiation Management, with particular attention to 

stratospheric sulfate aerosols, and marine cloud whitening. I will try to respond to 

the specific questions that you listed in your letter, and will also provide additional 

information where I think it relevant. 

What is Solar Radiation Management? Solar Radiation Management refers to 

the idea that mankind might be able to influence the amount of sunlight reaching 

the surface of the Earth deliberately. Scientists sometimes use the terms ‘‘radiation’’, ‘‘light’’, ‘‘energy’’ and ‘‘heat’’ in this context interchangeably. So ‘‘Solar Radiation Management’’ really means, ‘‘managing the amount of sunlight reaching the 

Earth’s surface’’. The global temperature of the planet is determined by the Earth 

system finding a balance between the energy absorbed from sunlight, and the energy leaving the atmosphere as radiant energy (heat) in the infrared part of the 

electromagnetic spectrum. The idea behind Solar Radiation Management is that if 

mankind could find a way to make the planet a little more reflective to sunlight, 

then less would be absorbed by the Earth, and the planet will be slightly cooler than 

it would otherwise be. So Solar Radiation Management is designed to cancel 

some of the warming that we expect from increasing Greenhouse Gas Concentrations.

Note that even if Solar Radiation Management succeeds, it will not cancel all the effects of increasing greenhouse gas concentrations. The increasing acidity of the oceans with its impact on ocean life is a good example of a consequence of increasing CO2 that will not be treated by Solar Radiation Management. 

Before jumping in further, I want to get past a few ‘‘buzzwords’’ immediately. 

From here on I will often replace the term ‘‘Solar Radiation Management’’ with the 

word ‘‘geoengineering’’. And I will often loosely refer to the ‘‘changes in the amount 

of energy entering or leaving some part of the planet because of some climate factor’’ 
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as a ‘‘forcing’’. So there is a forcing associated with increasing greenhouse gases, and 

there is another forcing associated with Solar Radiation Management. The idea is 

to try to match the forcings so that they kind of cancel. 

Preliminary Remarks on Geoengineering Research Goals and Expected 

Outcomes: There are many uncertainties in geoengineering research. Identifying 

the consequences of geoengineering to the climate of the planet is at least as difficult as identifying the changes to the planet that will occur from increasing greenhouse gases. Just as scientists cannot be certain of all of the consequences of doubling (or more) the concentration of CO2 to the planet, we cannot be certain of the 

outcome of any particular strategy for geoengineering the planet to counter that 

warming. What science can do is use the same tools and body of knowledge to identify likely outcomes from either class of perturbations to the planet. 

I am not sure we could ever be certain of the outcome of geoengineering. I think 

it is important to recognize that geoengineering is a gamble. The decision to try 

geoengineering in the end will probably be based upon balancing the consequences 

of a negative outcome from geoengineering against the negative outcome from ‘‘not 

geoengineering’’. 

I believe there are a variety of activities to consider for geoengineering research:

• Assessment, Integration: to brainstorm, review suggested strategies, and 

identify obviously unsuitable suggestions. Only a little work has been done 

to evaluate proposed strategies for efficacy and costs (e.g. Royal Society report, 2009 and Lenton and Vaughan, 2009).

• Computer Modeling: There are a variety of kinds of modeling studies that 

are relevant to geoengineering.

Æ Climate models and Earth system models are needed that provide a global view about interactions between many parts of the climate system over 

time scales as long a centuries.

Æ ‘‘Process Models’’ that include a lot of detail about one specific feature of 

the Earth system are also needed. These kinds of models might describe 

how for example cloud drops might form, but they neglect anything that 

isn’t central to that understanding, like what the rainfall was a thousand 

miles away. They do calculations that are generally far too expensive to 

be used for a global computer calculation but they are incredibly useful 

for understanding how a particular process operates. Science frequently 

uses global models to produce a broad view of geoengineering outcomes, 

but for those strategies that look promising, increasingly stringent levels 

of analysis are required to see whether the simple assumptions used in 

a climate model hold up. Process models are used to understand important details.

Æ Other models may also be needed for a broader set of questions (for example the impact of geoengineering on ecosystems or the economy).

• Lab and Fieldwork: Lab and fieldwork are critical to assure a thorough understanding of the fundamental physical process important to climate and 

that computer models are reasonably accurate in representing that process. 

I think it is critical to distinguish between ‘‘small scale field studies’’ where 

we might introduce some particles into the atmosphere over such a small 

scale that they would have negligible climate impact, and ‘‘full scale deployment’’ where we expect to actually have a climate impact. Field studies might 

try to induce a deliberate change to some feature of the earth system at a level 

with a negligible impact on the climate, but the change would allow us to detect a response in a component important to climate. For example, with Cloud 

Whitening one might try to modify a cloud, or a group of clouds by introducing a change over a very small area, over and over again for a month, to 

see whether we really understand how that kind of cloud works, and whether 

models can reproduce what we see in the real world. With Stratospheric 

Aerosols one might envision devoting a few aircraft to trying to deliver the 

material needed to make aerosol particles in the stratosphere, and then look 

to see whether the right size particles form, and how long they last.

• Technology Development: to develop equipment and measurement strategies that might be used for process studies, for exploratory trials, or as prototypes for full deployment. Some work has been done to develop plans for the 

devices needed for the cloud whitening strategy, and the ships that could deploy the sea salt particles.

• Deployment Activities: Obviously, one can envision a gradation of experiments to the climate, ranging from those with no impact, to those having a 
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huge impact. I am going to reserve the word ‘‘deployment’’ to refer to 

geoengineering designed to have a big impact on climate. I don’t 

think scientists know enough today about geoengineering, and so I 

don’t think we are ready for ‘‘deployment’’. I am going to avoid much 

discussion of full deployment scenarios for the rest of my testimony 

except to tell you what a climate model says might happen, and to acknowledge that when and if we think we understand geoengineering 

well enough to deploy it we must consider many new issues. Monitoring, infrastructure, energy consumption, economic modeling, governance, 

and much else are needed if we reach a stage where deployment is viable.

Preliminary Remarks on Costs associated with Geoengineering Research.

The costs are determined in large part by the goals of the research, and the outcomes that are to be achieved. 

In my opinion before a nation (or the world) ever decided to deploy a full scale 

geoengineering project to try to compensate for warming by greenhouse gases it 

would require an enormous activity, equivalent to that presently occurring within 

the modeling and assessment activities associated with the Intergovernmental Panel 

on Climate Change (IPCC) activity, or a Manhattan Project, or both. It would involve hundreds or thousands of scientists and engineers and require the involvement of politicians, ethicists, social scientists, and possibly the military. These 

issues are outside of my area of expertise. Early ‘‘back of the envelope’’ calculations 

estimated costs of a few billion dollars per year for full deployment of a stratospheric aerosol strategy (see for example, Crutzen, (2006) or Robock et al (2009b)). 

These numbers are very rough. I am not sure it is worth refining them much at 

this time, due to the many uncertainties that need to be resolved by exploratory research. 

There are many smaller steps that can be taken to make initial progress on understanding geoengineering at a much lower cost, and at a level that does not require an international consensus, or actually introduce significant changes in the 

Earth’s climate. These steps are worth doing because they allow us to identify obvious deficiencies in geoengineering strategies, and revise or abandon the problematic 

strategies. 

To put my recommendations on future research in context, I want to start by summarizing the research taking place today, and estimating the costs associated with 

that research. 

The research that has been done so far has been done on a shoestring budget. I 

am aware of 3 research groups in the U.S. that have done substantial 

geoengineering research in the last five years (I believe there are now 4 groups). 

Some of that work was done by postdoctoral researchers or students with fellowships allowing the freedom to work on any topic of their choice. Other work was 

done because a faculty member or a scientist like myself (in my previous position) 

had some small amount of flexibility in his or her appointment that allowed them 

to do research on geoengineering for a small fraction of their time. I believe that 

there are now two very small research grants sponsored by U.S. government agencies that explicitly support GEOE research totaling about $200,000/year. The ‘‘implicit’’ funding I described might double that contribution. Foundations have also 

contributed funding for geoengineering that may amount to another $500,000 per 

year. 

I estimate the total (2009) budget for all geoengineering research within the U.S. 

is probably $1M/year or less. Perhaps half of that is from private foundations.

There is a single major European Proposal funded by the E.U. at $1.5 Million per 

year to fund geoengineering research, and a number of activities started in the 

United Kingdom on geoengineering that total perhaps $1.6 Million per year. I believe that Germany is also now considering funding some geoengineering research. 

I think the Apollo Program to send a man to the moon took place over about 10 

years, and ran about $20 Billion dollars (http://spaceflight.nasa.gov/history/apollo) 

so that comes to about $2 Billion per year. And those costs are not cast in today’s 

dollars, so it would appear to be more if we adjusted for inflation. 

I estimate from the U.S. Climate Change Science Program 2009 budgets (http:/

/www.usgcrp.gov/usgcrp/Library/ocp2009/ocp2009-budget-gen.htm) that the total 

for climate science in the U.S. is about $l Billion per year. 

So the current spending on geoengineering research is tiny compared to these activities. And maybe it should be, that is not for me to decide. I think that is your 

job in part. But I can tell you that $10, 20, or $50 Million per year would have an 

enormous effect on the research activity in this area. 

Finally, it is worth writing a little bit about costs of field experiments. Although 

the comprehensive, international and successful VOCALS field research experiment 
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conducted off Chile in 2008 had no geoengineering component to it, the range of 

techniques and measurement strategies involved were very similar to those required 

for a limited-area field test of the cloud whitening scheme discussed below. VOCALS 

cost $20–25 Million. 

Now, on to your questions.

How does stratospheric sulfate aerosol achieve the necessary radiative 

forcing? 

Mankind has known for many years that the planet cools following a moderately 

strong volcanic eruption (like Pinatubo). We believe that the planet cools because 

volcanoes inject a lot of a gas called sulfur dioxide into the layer of the atmosphere 

called the stratosphere (a stable layer in the atmosphere with its base at about 

10km near the poles, and about 18km at the equator). This gas undergoes a series 

of natural chemical reactions that end up producing a mixture of water and sulfuric 

acid in small droplets we call sulfate aerosols. These sulfate aerosols act like small 

reflectors that scatter sunlight. Some of the sunlight hitting these drops gets scattered down, and some up. The part that goes up never reaches the surface of the 

Earth and so the Earth gets a bit cooler than it would otherwise. 

The geoengineering idea is to inject a ‘‘source’’ for aerosols into the same region 

of the atmosphere that volcanoes tend to inject the gas. I use the word ‘‘source’’ to 

refer to either a gas like sulfur dioxide (or another gas that will eventually react 

chemically and form sulfate aerosols), or to inject sulfuric acid (or some other particle type) directly. The expectation is that similar particles to those following a volcanic eruption will form from that source, and the earth will undergo a cooling similar to a volcano. The idea is to reduce the amount of energy reaching the surface 

of the earth to introduce just enough to balance the warming caused by increases 

in greenhouse gases. If the particles were like those that formed after Pinatubo we 

think that an amount like one quarter of that injected by Pinatubo per year would 

balance the warming that we expect from a doubling of CO2 concentrations if it 

were injected at tropical latitudes. These numbers might change if the aerosols were 

injected in Polar Regions. 

You might also be interested to know that scientists have occasionally considered 

using other kinds of particles to do geoengineering. But you asked me to focus on 

sulfate aerosols so I will not discuss other particles further. 

Scale and amount of materials needed. The amount of material needed depends upon the size of the particles that form. Little particles are better reflectors 

than big particles, and big particles also settle out faster than little ones do, so it 

is desirable to keep them small. Unfortunately, the size of the particles that form 

is a really complicated process. It depends upon whether particles already reside in 

the volume where the source is introduced. If particles already exist near the place 

the source is introduced then the source will tend to collect on the existing particles 

and make them bigger, rather than making new small particles. One of the main 

challenges to this geoengineering strategy is finding a way to continue to make 

small particles. One very recent paper (Heckendorn et al, 2009) suggests that first 

studies underestimated how quickly big particles will form, and that more of the 

source will be needed than the first studies assumed (perhaps 5 times as much). 

One challenge to this type of geoengineering research is to establish whether it is possible to produce small particles deliberately at the appropriate altitude for long periods of time.

Over what time period would deployment need to take place? 

If the geoengineering works as we have seen in climate models [that is, it cooled 

the planet] there would be very strong hints that the strategy was working within 

a couple of years of deployment. Scientists would certainly be more comfortable considering averages of 5 to 10 years of temperature data before making very strong 

statements about temperature changes. It would also take multiple years to sort out 

all the consequences (good and bad) to precipitation, sea ice, etc. Some of the known 

negative consequences from this type of geoengineering would be evident quickly 

(e.g. impact on concentrations of ozone in the stratosphere, changes in the amount 

of direct sunlight useful for solar power concentrators, and other consequences discussed in Rasch et al, 2008 and Robock 2009). Some effects, like those on ecosystems, might take more years to manifest. I don’t think anyone has yet looked 

at impacts on ecosystems. 

How would we do the deployment? This geoengineering strategy would require deploying the particle source year after year, for as long as society wanted to 

produce a cooling. Aerosols introduced in the stratosphere will gradually mix into 

other layers in the atmosphere as they are blown around by winds or as gravity 
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draws them into lower layers where they are rapidly removed. Aerosols in the stratosphere tend to last about a year before being removed (shorter near the poles 

where the aerosols get flushed out faster, and longer near the equator). One strategy is to deploy the source near the equator, and allow the particles to spread as 

a thin layer over the whole globe (this is roughly how things worked for Pinatubo). 

This would apply a cooling that is relatively uniform over the globe. Model studies 

usually assume that the source would be introduced steadily near the equator over 

the course of a year. Another strategy might be to produce the particles only near 

the poles during the spring, and let them get flushed out over the course of a summer (because they are flushed out faster near the pole). While the aerosols are located above the poles, they would shield the sea ice to keep the poles cooler in summer, and then allow the aerosols to disappear during winter when there is no sunlight at the poles anyway. Robock (2009) has shown that the particles actually 

spread and produce a cooling beyond the Polar Regions. 

An important issue to note is that will be substantial difficulties in evaluating this geoengineering strategy without full deployment. This makes it 

difficult to improve our understanding slowly and carefully using field experiments that do not change the Earth’s climate. The issue is this. We know 

from volcanic eruptions that stratospheric aerosols reside at these high altitudes for 

long periods of time (months to a year or so), and over that time, no matter where 

the aerosols are initially produced, they will spread to cover quite a bit of a hemisphere. We also know stratospheric aerosols develop differently if a source is introduced where aerosols already exist compared to the way they would form if there 

are only a few aerosols around. A fully implemented geoengineering solution would 

require that the aerosols cover a very large area of the globe with high concentrations. So it is important that we study the aerosols in an environment where they 

exist in high concentrations. 

But to avoid introducing a large perturbation to the atmosphere with consequences to the Earth’s climate during exploratory tests it would be desirable to 

start by introducing the aerosol over a very small patch of the earth. However if 

one started with a small patch of aerosol, then it will mix with the rest of the atmosphere and dilute quite rapidly, and we do not expect the aerosol to evolve in 

the same way when the particles are dilute, as they would if there were a lot of 

them around. It will also be difficult to monitor their evolution if there aren’t many 

of them around. 

So we are caught between rock and a hard place. Too small a field test, and it 

wont reveal all the subtleties of the way the aerosols will behave at full deployment. 

A bigger field test to identify the way the aerosols will behave when they are concentrated will have an effect on the planet’s climate (like Pinatubo did), albeit for 

only a year or two. I have not seen a suggestion on how to avoid this issue. 

How long the direct and indirect impacts would persist: Model simulations, and 

observations of volcanic eruptions suggest that when the source is terminated, most 

of the aerosols would disappear in a year or two. Models suggest that the globally 

averaged temperature would respond by warming rapidly (over a decade or so) to 

the temperature similar to what would occur if no geoengineering had been done 

(Robock et al, 2008). The rapid transition to a warmer planet would probably be 

quite stressful to ecosystems and to society. There might be other longer timescale 

responses in the climate system (in Ecosystems (plant and animal life) because it 

takes many years for plants and animals to recover from a perturbation (think of a 

forest fire for example). Deep ocean circulations also respond very slowly, so it would 

take many years to influence them, and many years for them to recover. These effects 

have not been looked at in climate models and it is another area meriting scientific 

research.

State of Research on geoengineering by stratospheric aerosols Here is a 

very brief overview of research has been taking place given the current ‘‘shoestring 

budgets’’:

1. Assessment, Integration: As mentioned above, the papers by Lenton and 

Vaughan (2008), and the report of the Royal Society (citation) provide some 

assessments of this strategy compared to others. Those studies are already 

somewhat out of date, given the additional information from studies over the 

last two years.

2. Modeling: A number of papers have appeared in the scientific literature exploring consequences of geoengineering with stratospheric aerosols using 

global models. These studies essentially frame the questions by assuming 

that it is possible to deliver a source gas to the stratosphere, and that gas 

will produce particles similar to the ones produced after the Mount Pinatubo 

eruption. Then they proceed to ask questions like ‘‘What would be the effect 
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of those aerosols on the Earth System?’’ using standard climate modeling 

techniques. The community is beginning to transition from the first ‘‘quick 

and dirty look’’ (e.g. Robock et al, 2008; Rasch et al, 2008). Each modeling 

group that explored stratospheric aerosol geoengineering did it a different 

way. Alan Robock has proposed that modeling groups try to compare their 

stratospheric aerosol geoengineering studies in a more systematic for the 

next IPCC assessment. Only one group (Heckendorn) has tried to understand 

the details of formation and aerosol size evolution, and they used a model 

framework with a number of very significant simplifications. It would be desirable to remove those simplifications. It is also time to begin assessing the 

evolution of the source of the aerosol from the time it is delivered from an 

aircraft until it spreads to a larger volume (like a few hundred km). Rasch 

et al (2008) revisited research performed during the 1970s and 1980s to estimate the aerosol formation and evolution after the source is released from 

an aircraft.

3. Lab and Field Studies: I am not aware of any efforts to conduct or plan 

lab or field studies to understand component processes important for this 

kind of geoengineering.

4. Technology development: I am not aware of any efforts to assess or develop technologies for producing the stratospheric aerosols.

5. Deployment: There has been one study that tried to assess the cost of just 

lifting various candidate compounds to the needed altitude using existing 

technology (Robock et al, 2009). There have been no studies yet published 

that explore what the optimal source gas or liquid is, how it should be injected into the atmosphere, or how to optimally deliver it. I know that David 

Keith, who is also testifying here, has thought about this, and he can do a 

better job briefing you on this activity than I.

Cost estimates and recommendations for an improved research program 

for stratospheric Aerosols:

A few $10s of Million per year funding for research would allow substantial theoretical progress in geoengineering research through modeling, and perhaps some 

proto-typing of instruments to produce the aerosol source, and specialized instruments for measurement. It might be sufficient for a field program every other year.

Here is an incomplete list of some of the tasks that should considered in 

terms of the topics the committee charged me with addressing: 1) 

Research, 2) Deployment, 3) Monitoring 4) Downscaling, cessation 

and necessary environmental remediation, and 5) Environmental 

impacts:

1) Research: There are many opportunities for research. Here are a few ideas.

Detailed Models

a. Systematic assessment of particle formation and growth using size resolved aerosol models. Two different kinds of models would probably be 

required: 1) A plume model to deal with the evolution of the particles 

from source release to the point that the plume has grown to maybe 

10km in horizontal extent and a few hundred meters in the vertical, 2) 

a size resolved aerosol model to track the particle evolution from 10km 

until the aerosol has been removed. Investigator could be tasked with exploring whether one would inject particles or a gas as a source, the strategies for the temporal and spatial scales of injection, and sensitive to the 

environment that the source is injected (e.g. do the particles developed 

differently if the air already contains aerosols).

Global Models

a. Global models indicate a number of positive and negative consequences 

to the planet from geoengineering. The first ‘‘quick and dirty’’ calculations described above produced different cooling responses, and different 

precipitation responses in different models. We don’t yet know whether 

the differences are due to model differences, or different assumptions 

about emissions, particle size, etc. It would be good to systematize studies of geoengineering across multiple models to help in assessing uncertainty about the effect of geoengineering.
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b. We need to make sure that the global models are producing similar pictures of aerosol formation, coalescence and removal to the picture provided by the detailed process models.

c. Very little work has been done in exploring sensitivity to injection scenarios. For example we don’t know whether the geoengineering may 

have a different impact if we produce the aerosol at a constant rate over 

a year, or mimic a volcanic injection every other year.

d. There has been no assessment of the impact of the geoengineering aerosol on homogeneous nucleation of ice clouds

e. There has been no exploration of how changes in how geoengineering 

might affect ecosystems (plants and animal health)

2) Field testing and Deployment

a. How do we deliver the source to the region of release? A variety of delivery mechanisms have been proposed, but none have been tested, and no 

engineering details have ever been developed to the point that costs 

could be assessed.

b. Once we have a detailed idea of precisely what source we want, can we 

produce that source?

c. Plan an exploratory field experiment to help understand the formation 

and evolution of the particles for the first few weeks. After injecting the 

source in the stratosphere do particles form as models suggest? How do 

we track the plume? What instruments are required to measure the particle properties, the plume extent, and the reduction in sunlight below 

the plume. Do the particles coagulate and grow as our models suggest? 

Do the particles mix and evolve the way our models tell us they will 

(from source to the first scale, and from the first scale to the globe 

scale?).

3) Monitoring: We don’t have much capability of monitoring the details of sulfate 

aerosol from space any more (we had better capability in the past before the NASA 

SAGE instrument died). This issue is documented in some of the contributions submitted by Allen Robock in the previous hearing. It would also be good to develop 

a ‘‘standing task force’’ that was capable of monitoring the detailed evolution of the 

aerosol plume following a volcanic eruption. This would allow us to gain significant 

understanding of plume evolution without the need to produce a source for the aerosol.

4) Downscaling, cessation, environmental remediation.

a. The only insight that we have about impacts of the geoengineering by 

sulfate aerosols come from that gained from the global climate model 

studies, and seeing the impact of climate changing volcanic eruptions. 

Both classes of studies suggest that if the source for stratospheric 

aerosols was turned off, the aerosols go away within a year or two, and 

the climate returns to a state much like it was before the stratospheric 

aerosols over a decade or so. The rapid return of temperature to the 

ungeoengineered state would probably produce significant stresses to society, and ecosystems, but no studies have been done to explore this.

5) Environmental Impact: There are a variety of possible environmental consequences, which have been described in the studies by Rasch and Robock submitted 

at the last hearing. Among them are a) changes in the ratio of direct to diffuse sunlight, with possible impacts on ecosystem, and solar electricity generation; b) 

changes in precipitation patterns; c) changes in El Nin ̃ o.

Which U.S. Agencies might be involved: I can easily identify expertise and capability in the following agencies:

1) NASA (which has a long history of interest in particles and chemistry at the 

relevant altitudes through its High Speed Research Program and Atmospheric Effects of Aviation Programs, as well as the capability of remote sensing of particles and their radiative impact from space and the surface).

2) NSF (many university researchers can also contribute to the same parts of 

the project that are mentioned for NASA).

3) There are individual research groups within DOE and NOAA that could 

make important contributions to modeling, field campaign and measurement 

programs.
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How does marine cloud whitening achieve the necessary radiative forcing?

The idea behind ‘‘Solar Radiation Management’’ by ‘‘cloud whitening’’ is to make 

clouds a bit ‘‘whiter’’ (a bit more reflective to sunlight) than they would otherwise be.

Clouds are enormously important to the climate of the earth. Everyone has experienced the cooling that results on a hot summer afternoon when a cloud goes by 

overhead and shades the earth. This occurs because the cloud reflects the sunlight 

that would otherwise reach the surface and heat up the ground. Clear winter nights 

will frequently be much colder than a nearby night when the sky is overcast. This 

is because high clouds ‘‘trap’’ heat that would otherwise escape to space. So it is 

warmer when high ice clouds are around. 

These features of clouds acting to cool or warm the planet are (like the stratospheric aerosols) due to their impact on ‘‘radiation’’ (again loosely identified with 

‘‘energy’’, or ‘‘light’’, or ‘‘heat’’). Low altitude liquid clouds tend to cool the planet 

more than they warm it. High altitude ice clouds also act to warm the planet, by 

trapping some of the energy that would otherwise escape to space. Scientists believe 

the low cloud effect wins out in terms of reflecting or trapping energy, and clouds 

as a whole tend to cool the planet more than they warm it. 

It is easy to find a few places on the planet where we know that mankind makes 

clouds ‘‘whiter’’ (by which I mean more reflective) because we see evidence for it in 

satellite pictures. These are the areas where ‘‘ship tracks’’ occur. In these special 

regions dramatic changes occur in cloud properties near where the ships go. Scientists believe that the clouds are whiter due to the aerosols emitted as pollution 

by the ships as they burn fuel. The extra aerosols in the clouds change the way the 

cloud develops, and this makes it whiter, as I describe below. 

All clouds are influenced by (both man-made and natural) aerosols. Every cloud 

drop has an aerosol embedded in it. Cloud drops always form around aerosols. The 

way that aerosols interact with a cloud is determined by the size and chemical composition of the aerosol, and by the cloud type. To make an extreme simplification 

of a very complex process, the general idea of geoengineering a cloud goes like this. 

If one introduces extra aerosol into a region where a cloud is going to form, then 

when the cloud forms, there will be more cloud drops in it than there would otherwise have been. The term ‘‘seeding’’ has been introduced to describe the process of 

introducing extra aerosols into an area. It ends up that if cloud has more drops in 

it, then it tends to be whiter than if it had fewer drops. Again, this is a simplification. The whiteness also has to do with the size of each cloud drop, and how it 

changes the way that the cloud precipitates, but I am trying to keep the discussion 

short. 

It is possible to demonstrate the whitening effect by aerosols for many cloud types 

over many regions, but the effect is most dramatic in the clouds that form in ship 

tracks. 

The whiteness of a cloud is influenced by many factors. Aerosols are critical but 

certainly not the only important factor influencing a cloud. One type of cloud (for 

example midlatitude storm clouds seen in Washington in January) will respond differently to aerosol changes than another cloud type (for example the marine stratocumulus seen off the coast of California). 

The whitening phenomenon is believed to occur in many cloud systems, but the 

effect may be most important in marine clouds near the Earth’s surface. Also clouds 

generally become more important in reflecting sunlight over oceans because the 

ocean surface reflects less sunlight than the land or snow even without clouds, so 

putting a bright cloud over oceans cools the Earth more than if you put the same 

bright cloud over already bright land or ice. 

Scientists have speculated that geoengineering could be performed by whitening 

many clouds over oceans deliberately, rather than whitening a few of them 

accidently as we do today with ‘‘ship tracks’’. The idea is to introduce tiny particles 

made of sea salt into the air near where clouds might form, rather than the pollution particles produced by freighters, and to do it in a lot more places in a controlled 

and efficient way. Scientists think this seeding might make the clouds whiter, and 

thus make the planet reflect more sunlight, and become cooler. 

Conceptually, the idea is quite simple, but realistically many complications come 

into play. Clouds are enormously complex features of the atmosphere. While we 

know a lot about the physics of clouds, we aren’t good at representing their effects 

precisely. One of the most complex and uncertain aspects of clouds is in understanding and predicting how clouds interact with aerosols (the so called ‘‘Aerosol Indirect Effect’’). This complexity is well described in the Fourth Assessment by the 

Intergovernmental Panel in Climate Change (AR4, 2007). While we know that there 

are situations where additional aerosol will make a cloud whiter, we also believe 
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there are situations where putting extra aerosol into a cloud will make little or no 

difference. 

The idea behind cloud whitening as a geoengineering strategy is thoroughly described in a review paper by Latham (2008). Some hints about the complexities associated with changing cloud properties can be found in the papers by Wang et al 

(2009a, b). Some of the difficulties in treating aerosol cloud interaction are discussed 

in the paper by Latham et al (2008), and the papers cited there. A very recent review of the reasons why aerosol cloud interactions are so difficult to treat in models 

can be found in Stevens and Feingold (2009). Some preliminary scoping work has 

been done to consider how one might design a field experiment to explore changing 

the reflectivity of a cloud. This is discussed below. 

One very attractive consequence of doing a limited field test of whitening clouds 

by geoengineering is that it provides an opportunity to get a fundamental handle on 

the ‘‘Aerosol Indirect Effect’’. Trying to whiten a cloud, or a cloud system, is a fundamental test of our understanding of how a particular cloud type works, and of the 

ways in which clouds and aerosols interact. Because the Aerosol Indirect Effect is one 

of the critical and outstanding questions in climate change, doing that kind of field 

experiment would be of incredible value.

Scale and amount of materials needed: Latham et al (2008) and Salter et al 

(2008) have estimate that the total amount of aerosol that needs to be pumped into 

that atmosphere is about 30 m3 per second. They estimate that it might require X 

ships deployed over a large area (perhaps as much as 30% of the ocean surface) to 

distribute that sea. 

Over what time period would deployment need to take place and how 

would we do the deployment? One interesting and important difference between 

geoengineering using stratospheric aerosols, and geoengineering using cloud whitening is that the very short lifetime of clouds and aerosols near the surface (of a 

few days or less) means that if one is able to change clouds the changes will be local, 

and it should be possible to ‘‘turn on’’ and ‘‘turn off’ the changes in reflectivity of 

the clouds very quickly (on the time scale of a few days). 

There is a lot of variability in clouds, and scientists considering geoengineering 

by cloud whitening don’t expect to change clouds as dramatically as a ship track 

does. The changes will be subtle and some care will be required to ‘‘detect’’ the 

change in clouds. 

The fact that the response by clouds to the aerosols is immediate and local is good 

and bad. The positive aspect is that a meaningful experiment can be designed to 

try to change clouds in a small region for a short time. Since one can restrict the 

experiment this way it is possible to be very confident that a small test would have 

no discernable effect on the Earth’s climate, but it would be a meaningful test. (I 

have indicated that this is a difficult for Stratospheric Aerosol Geoengineering). One 

could imagine trying field experiment at successive locations to see whether it was 

possible to change particular types of cloud to gain knowledge and experience about 

cloud, aerosols, and cloud whitening. This means that designing a program to explore the cloud whitening concept and examine the impact on clouds in an incremental fashion is much easier than doing it with stratospheric aerosols. 

With either the stratospheric aerosol strategy, or the cloud whitening strategy the 

goal is to reduce the amount of sunlight reaching the Earth’s surface a bit. If the 

strategy spreads out the shading over a large area (as done with the stratospheric 

aerosol strategy) then it is not necessary to make much change in sunlight reaching 

the surface anywhere. If the strategy concentrates the changes over smaller areas 

(as done with the cloud brightening strategy) then the change in sunlight reaching 

the surface will be larger at those locations. So geoengineering by cloud whitening 

is likely to introduce stronger effects locally than would be seen in the stratospheric 

aerosols. 

If it does prove possible to deliberately change the whiteness of a cloud system, 

then it would be possible to ramp up the activity, increasing the ocean area and 

the duration of time that the cloud systems are affected to the point that the Earth’s 

climate should be influenced. Obviously larger and larger communities of stakeholders would need to be involved as scope of the project increased. 

If changing the cloud forcing was effective and it was ramped up to the point that 

it is influencing the climate then other issues must be considered. It ends up that 

the local changes in cooling patterns are likely to set up stronger responses in 

weather and ocean currents than the broader and weaker patterns seen with the 

stratospheric aerosols. Also, it is the case that the clouds that are believed to be 

most easily influenced by the cloud whitening reside in the subtropics, so the reduction in the amount of sunlight reaching the surface will tend to be strongest in those 

regions. Since the atmosphere and ocean distribute the heating and cooling through 

winds and currents the effect will eventually be distributed over the globe, but the 
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difference in the weather or precipitation for example may still be more evident in 

the cloud whitening than the stratospheric aerosol strategy. 

However, there are many processes in the Earth System that would take much 

longer to respond (with timescales of weeks, months, and years). If society were to 

‘‘turn on’’ cloud whitening globally we would probably see noticeable effects on surface temperature within a couple years. We might also see any negative consequences (e.g. changes in some major precipitation systems, if those changes were 

to occur) within a few years, although it would take a number of years to feel confident in documenting the positive or negative changes in climate (as also seen with 

stratospheric aerosol geoengineering). 

How long the direct and indirect impacts would persist: As far as I know, 

no one has explored the response of the Earth system if geoengineering by sea salt 

aerosols were terminated in a climate model, and there are no natural analogues 

like there are with stratospheric aerosols and volcanoes. I expect that after terminating the source for the aerosols, the aerosols perturbations would disappear over 

a few days. Like the stratospheric aerosols, I would expect after removal of the 

geoengineering forcing to see a rapid return (on the timescale of a decade or so) to 

the globally averaged temperature similar to a world experiencing only high concentrations of greenhouse gases. Again, there will probably be longer timescale responses in the Earth System of a more subtle nature (for example some ocean circulations will take years to respond, and there could be long term responses in ecosystems). As with the stratospheric aerosol strategy, these issues should be explored. 

State of Research on geoengineering by cloud whitening. Here is a very 

brief overview of recent research with the current ‘‘shoestring budgets’’:

1. Assessment, Integration: The report of the Royal Society (2009) provides 

some assessments of this strategy compared to others.

2. Modeling:

Global Models

a. A number of papers have appeared in the scientific literature exploring 

consequences of geoengineering with cloud whitening using global models (Rasch et al 2009; Jones et al 2008). These studies essentially frame 

the questions by assuming that it is possible to control the number of 

drops in a cloud system perfectly. Then they proceed to ask questions 

like ‘‘what would the effect be of those cloud changes on the Earth System’’ using standard climate modeling techniques. The community is beginning to transition from the first ‘‘quick and dirty look’’ to a more thorough exploration of the subtleties of the strategy (e.g. Korhonen et al, 

2010) although that study still employed some significant simplifications 

compared to the state of the art in aerosol and climate modeling.

b. Each modeling group that has explored cloud whitening geoengineering 

has assumed different ways of producing cloud changes, and introduced 

those changes at different longitudes and latitudes, and made different 

assumptions about greenhouse gas concentrations changes. There have 

been no attempts yet to systematize these scenarios and explore variations on them.

Process Models

a. There has been some recent work with Large Eddy Simulation studies 

on ship tracks by Wang (2009)

3. Lab and Field Studies: No recent field studies have been done with cloud 

whitening. In 2008 a field experiment called VOCALS took place to study clouds and 

cloud aerosols interactions off the coast of Peru and Chile. This field experiment had 

no geoengineering component to it but the clouds systems in that region are of the 

type relevant to geoengineering, and the range of techniques and measurement 

strategies involved were very similar to those required for a limited-area field test 

of cloud whitening, and it could be used to estimate costs for limited field testing. 

There have been earlier field studies to measure cloud changes following ship tracks 

(for example, MAST, the Monterey Ship Track experiment), and I believe another 

similar study is being planned by B. Albrecht and J. Seinfeld. 

4. Technology Development: Some exploratory work in developing spray generators to produce the appropriately sized sea salt particles for seeding the clouds 

has been done in two groups, one led by Armand Neukermans in California, and 

another led by Dan Hirleman at Purdue. 

5. Deployment: I don’t think we are ready to address this issue 

6. Interactions with other communities: I don’t have the expertise to provide 

guidance on this issue, but I am interested.
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Cost estimates and recommendations for an improved research program 

for cloud whitening.

I see three logical phases to research in exploring cloud whitening. I believe only 

the first phase should be considered at this time. The others require much more discussion, governance, and involvement by national and international stakeholders 

and planning.

• Phase 1: Using Models, and extremely limited field experiments where there 

is no chance of significantly effecting to the climate to determine whether it 

is actually possible to whiten clouds in a predictable, controlled manner. Are 

there changes to other cloud properties (for example, cloud precipitation, 

cloud height, cloud thickness)

• Phase 2: Enlarge the scope of the geoengineering research and consider the 

consequences if we were to whiten cloud for long enough that it might actually make a difference to local climate. Look at the consequences to the local 

environment on short time scales (like less than a week). These consequence 

might matter to people, but they would be small compared to the kind of 

ways we already perturb the climate system (like the forest fires in Borneo, 

a Pinatubo, etc)

• Phase 3: Full scale deployment.

Again, progress would be increased immediately by funding and attention for all 

of these activities. If the cloud whitening actually proves successful during the 

smallest scale tests then the deployment issues become important, and a second 

phase of research and development become necessary. 

For the initial exploratory phase, $10 Million per year funding for research would 

allow substantial theoretical progress in geoengineering research through modeling, 

and perhaps some proto-typing of instruments to produce the aerosol source, and 

specialized instruments for measurement. 

The 2008 VOCAL field campaign might serve as a reasonable estimate of the cost 

of a first class one-time field experiment with a focus on aerosol cloud interaction 

in the right kind of cloud system. That field experiment cost over $20 Million. 

Thus, a strong initial effort to study cloud whitening might well be funded at $20–

$25 million per year, assuming a field study every 2–3 years. 

Here is an incomplete list of some of the tasks that should be considered in terms 

of the topics the committee charged me with addressing: 1) Research, 2) Deployment, 

3) Monitoring 4) Downscaling, cessation and necessary environmental remediation, 

and 5) Environmental impacts:

1. Theoretical Research and Technology development:

Process Models

a. The first studies by Wang (2009) using ‘‘Large Eddy Simulation’’ model 

for ship track research should be extended to explore the problem from 

a geoengineering point of view. Investigators could be tasked with exploring how to optimize the injection of the aerosols (how many ships per 

cloud region, whether it makes a difference if the cloud system has already formed or is expected to form soon, sensitivity to diurnal cycle of 

boundary layer clouds, sensitivity to levels of background aerosol (pollution levels). This would require simulations over larger domain, longer 

time frames, different cloud regimes, perhaps with more complex formulations of cloud and aerosol microphysics.

b. Very high resolution modeling studies should be performed of the evolution of the aerosol particles as they are emitted from the seed generator until they enter a cloud.

Global Models

a. Make emission scenarios uniform across multiple models

b. Impact on precipitation 

c. Make sure models are consistent with the picture provided by the detailed models

Technology Development

d. We need to develop equipment that is capable of producing the aerosols 

that will be used to seed the clouds.

2. Deployment: The knowledge and technology are not yet at a stage where deployment should be considered. The research program will change completely if research indicates it is possible to whiten clouds in a controllable and reproducible 

way. 
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3. Monitoring: During the first phase, while trying to establish whether cloud 

whitening is viable; monitoring should be consider part of the field campaign. The 

picture will change completely if deployment becomes viable and much more work 

is required to scope out a monitoring activity.

4. Downscaling, cessation, environmental remediation.

a. During phase 1 there should be no impact on the climate.

b. If a geoengineering solution were to be deployed, The only guidance we 

would have on this is research from global climate models. There are no 

analogues that come to mind in nature for cessation of geoengineering 

by cloud whitening. My suspicion is that climate models would show a 

recovery quite similar to that discussed in the section on stratospheric 

aerosols. This kind of study should be performed.

5. Environmental Impact: Because geoengineering has the potential for affecting precipitation patterns, and major circulation features like ENSO and monsoons, 

there are many ways in which it can have an environmental impact, with consequences to society and ecosystems. This issue will be very important in a ‘‘Manhattan’’ level activity if phase 1 research ever succeeds and deployment is seriously 

considered. 

Which U.S. Agencies might be involved: NASA, NSF, DOE and NOAA all 

have relevant responsibilities and expertise for the Phase 1 activities.

Closing Remarks:

Thank you for asking me to testify. I have tried to respond to you questions, and 

provide some of the answers, although I think that science does not know enough 

to answer completely. 

I would like to leave you with a few take home messages.

1. I recognize that geoengineering is a very controversial and complex subject, 

and that there are many issues associated with it of concern to scientists and 

society. It can, for example, be viewed as a distraction, or an excuse to avoid 

dealing with greenhouse gas emissions. Scientists interested in 

geoengineering want to be responsible and transparent. We care about doing 

the science right, and in a responsible way. We believe that our energy system transformation is proceeding too slowly to avoid the risk of dangerous 

climate change from greenhouse gases, and that there has been little societal 

response to the scientific consensus that reductions must take place soon to 

avoid the risk of large and undesirable impacts.

2. Geoengineering should be viewed as a choice of last resort, It is much safer 

for the planet to reduce greenhouse gas emissions. Geoengineering would be 

a gamble. Just as there are many uncertainties associated with predicting 

the kind of changes to our climate from increasing greenhouse gases, there 

will be similar uncertainties to predicting the changes from geoengineering.

3. Current Climate models indicate that geoengineering would cool the planet 

and compensate for some, but not all of the consequences of increased greenhouse gases.

4. I don’t think scientists know enough today about consequences of 

geoengineering to climate, and so I don’t think we are ready for ‘‘deployment’’. Before anyone should consider full-scale deployment of a 

geoengineering strategy, lots of basic work (what I call phase 1 research) 

could be done to lay the groundwork for deployment. The basic work will 

help in eliminating unsuitable strategies, in identifying important issues to 

hone in on, to help us revise strategies to make them more suitable for deployment, and in some cases could help in revealing fundamental information critical for understanding climate change (I am thinking about information about the ‘‘Aerosol Indirect Effect’’ when I refer to the issue of critical 

understanding).

5. Right now, less than $1 million per year is spent on geoengineering research 

in the US. A viable research activity with a chance of making rapid, solid 

progress including field studies would probably require $20–40 million per 

year for either program.

6. I believe that if phase 1 research does come up with a promising strategy 

for geoengineering, and deployment is seriously considered, that the level of 

scrutiny and level of funding must increase very sharply to a level similar 

to that of a ‘‘Manhattan Project’’. Such a project would need to consider many 

issues beyond the physical sciences.
165

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166

BIOGRAPHY FOR PHILIP RASCH

Dr. Philip Rasch serves as the Chief Scientist for Climate Science at the Pacific 

Northwest National Laboratory (PNNL), a Department of Energy Office of Science 

research laboratory. In his advisory role, he provides leadership and direction to 

PNNL’s Atmospheric Sciences and Global Change (ASGC) Division. The Division 

conducts research on the long-term impact of human activities on climate and natural resources using a research strategy that starts with measurements and carries 

that information into models, with a goal of improving the nation’s ability to predict 

climate change. 

Dr. Rasch provides oversight to more than 90 researchers who lead and contribute 

to programs within a number of government agencies and industry. These programs 

focus on climate, aerosol and cloud physics; global and regional scale modeling; integrated assessment of global change; and complex regional meteorology and chemistry. 

Dr. Rasch received a Bachelor Degree in Atmospheric Science and another in 

Chemistry from the University of Washington in 1976. He then moved to Florida 

State University for a Master of Science in Meteorology. He went to the National 

Center for Atmospheric Research (NCAR) in Boulder, Colorado as an Advanced 

Study Program (ASP) Graduate Fellow to complete his PhD (which was also awarded from Florida State University). Following his PhD, Rasch remained at NCAR, 

first as ASP Postdoctoral Fellow, and then as a scientist where he worked in various 

positions. He joined PNNL in 2008. Rasch also holds an adjunct position at the University of Colorado and is an Affiliate Professor in the Department of Atmospheric 

Science at the University of Washington. 

Dr. Rasch is internationally known for his work in general circulation, atmospheric chemistry, and climate modeling. He is particularly interested in the role of 

aerosols and clouds in the atmosphere, and has worked on the processes that describe these components of the atmosphere, the computational details that are needed to describe them in computer models, and on their impact on climate. For the 

last five years, he helped to lead the technical development team for the next generation of the atmospheric component of the Community Climate System Model 

Project, one of the major climate modeling activities in the United States. He also 

studies geoengineering, or the intentional manipulation of the atmosphere to counteract global warming. 

Dr. Rasch was a chair of the International Global Atmospheric Chemistry Program (IGAC, 20042008), and participates on the steering and scientific committees 

of a number of international scientific bodies. He was named a fellow of the American Association for the Advancement of Science, recognized for his contributions to 

climate modeling and connecting cloud formation, atmospheric chemistry and climate. He has contributed to scientific assessments for the World Meteorological Organization, NASA and the Intergovernmental Panel on Climate Change. 

Chairman BAIRD. Thank you, Dr. Rasch. 

Dr. Lackner. 
167

STATEMENTS OF DR. KLAUS LACKNER, DEPARTMENT CHAIR, 

EARTH AND ENVIRONMENTAL ENGINEERING, EWING 

WORZEL PROFESSOR OF GEOPHYSICS, COLUMBIA UNIVERSITY 

Dr. LACKNER. Chairman Baird, Mr. Inglis, Members of the Committee, thank you for inviting me. I am delighted to be here. It is 

a great honor. 

I was a little bit puzzled though to start with why I would think 

of this, what I do, air capture and mineral sequestration as 

geoengineering. But then I started on reflection to think well, we 

have to stabilize the CO2 in the atmosphere against 30 billion tons 

or more in the future of CO2 emissions. That, by anybody’s scale, 

would be considered geoengineering, and in my view, we will have 

to stabilize carbon dioxide in the atmosphere sooner or later, and 

it doesn’t really matter whether we manage to do it right away or 

whether we fail and it takes a longer time and we stabilize at a 

higher level. As we reach stabilization, we have to balance out all 

emissions. We have to go to a net zero carbon economy, and I focus 

on capture and storage—these are capture and storage options—because I firmly believe that we have to solve the problem 

directly and not just mask the symptoms. We may have to do that 

for a short time but ultimately one has to solve the problem, which 

means managing that all the carbon which goes out is balanced 

against something else. 

That means in turn we need comprehensive solutions for carbon 

capture and storage, and I would put air capture and mineral sequestration into that larger category. I would argue that carbon 

capture and storage has to be more comprehensive than just power 

plants, and we have to have the ability to store carbon anywhere 

and at the requisite scale because we have the ability to put out 

one or two Lake Michigans in terms of mass of CO2 over the next 

century. We better find a way to put all of this away, and this is 

where in my view mineral sequestration comes in as an important 

part. 

Let me begin briefly with the air capture and storage, and I 

would argue what makes this so nice is it separates the sources 

from the sinks. One of the side effects is, you will actually get a 

group of players who want to solve the problem and not just get 

dragged in because they must solve the problem. I think that is important, but most importantly, it allows us to rely on the future on 

liquid fuels. These fuels could come from oil, they could come from 

coal, they could come ultimately from biomass or from synthetically 

made processes which started with CO2 in the first place and renewable energy, but whatever liquid fuel you had and burned in 

an airplane or a car will go into the atmosphere and will have to 

be taken back. Ultimately, CO2 capture from the air allows you to 

reduce CO2 levels in the air back down, and that makes it important. 

The basic idea of the technology is actually quite simple. You can 

do it in a high school experiment. As a matter of fact, my daughter 

did just that. Really, the issue is cost and scaling. You have to 

build collectors, and what we found out, they are actually surprisingly small, and you then move them up to larger and larger 

scales. What we are working on right now is an attempt to go to 
168

roughly one-ton-a-day units, and I can show you here what we can 

do in the laboratory right now. This actually is sort of a synthetic 

pine branch, as people talk about it, as CO2 capture devices. This 

guy is loaded with CO2 because he has been in my briefcase all 

day, and he picked up the CO2 while we were coming down here. 

Ultimately, we have to get the large scale of one ton a day. These 

units as they are mass-produced would be like cars. You would 

need 10 million to make a real dent in the CO2, 10 million of those, 

maybe 100 million if you wanted to solve the problem exclusively, 

but keep in mind, in order to have 10 million units running, you 

would need one million production a year, which is a tiny fraction 

of the world car production. Cars and light trucks add to roughly 

750 million. Ultimately, it comes down to cost. We are predicting 

that once it is mass-produced, it would operate at about 25 cents 

per each gallon of gasoline, and that is the price for cleaning up 

climate and cleaning up after yourself. 

Ultimately, let me say a few words about mineral sequestration. 

I view that as carbon storage version 2.0. It is bigger in scope. It 

can literally deal with all the carbon we ever have. It is definitely 

permanent. There is no question. It doesn’t require monitoring because you did take the geological weathering cycle and you accelerated it artificially, and once you have done that, there is no way 

back. So you can break it into xenon tube where you mine the rock 

and then process it, which turns out is big, but is no bigger than 

coal-mining operations we have to produce the coal which produces 

the CO2. And ultimately you also have in situ. I am involved in a 

project in Iceland where we put CO2 underground for forming carbonates under ground, and the nice feature there is, you can come 

back in 25 years and say it actually is permanently stored. Monitoring beyond that time is not necessary. 

The challenge here in my view is cost. We are roughly five times 

more expensive then we should be at this point, in my view, and 

I think that is an R&D challenge. If I look at the other sources of 

energy, I would argue a factor two is well within what can be done. 

So to me, air capture and mineral sequestration provide a comprehensive solution. Under that umbrella will be better specific solutions. It makes no sense to not scrub a power plant and then go 

after it from the air. But I believe we ultimately have a big challenge that the energy infrastructure of the year 2050 is not yet understood, and I think therefore I have a can-do attitude, but you 

can only do by doing and you can only learn by doing and you have 

to do the research to make it happen. Energy is so central to our 

well-being that I think we should not take the risk of not knowing 

what to do in 50 years from now and put a reasonable large-scale 

research effort behind this. I thank you for your attention. 

[The prepared statement of Dr. Lackner follows:]

PREPARED STATEMENT OF KLAUS LACKNER

Air Capture and Mineral Sequestration

Tools for Fighting Climate Change

Summary 

Thank you for giving me the opportunity to express my views on air capture and 

mineral sequestration, two of the technologies that are included in this hearing as 

geoengineering approaches to climate change. 
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1For a more detailed discussion see Lackner, K. S. (2010), Comparative Impacts of Fossil 

Fuels and Alternative Energy Sources, in Issues in Environmental Science and Technology: Carbon Capture, Sequestration and Storage, edited by R. E. Hester, and R.M. Harrison, pp. 1–40. 

Together, air capture and mineral sequestration provide a comprehensive solution 

to combat climate change. Capturing carbon dioxide from the air and storing it safely and permanently as solid mineral carbonate provides a way to maintain access 

to plentiful and affordable energy, while stabilizing the carbon dioxide concentration 

in the atmosphere. Abandoning fossil fuels would seriously affect energy security. 

On the other hand, the continued emission of carbon dioxide would have harmful 

consequences for climate, oceans, and ecosystems. Air capture can extract unwanted 

carbon from the atmosphere, and mineral sequestration can provide a virtually unlimited and safe reservoir for the permanent storage of excess carbon.

Introduction 

Stabilizing the concentration of carbon dioxide in the air requires reducing carbon 

dioxide emissions to nearly zero. Think of pouring water into a cup; as long as you 

pour water into the cup, the water level in the cup goes up. It does not matter 

whether the maximum level is one inch below the rim or one and half inches below 

the rim. In either case, you will eventually have to stop pouring. 

Stopping or nearly stopping carbon dioxide emissions cannot be achieved with energy efficiency and conservation alone. These steps will slow the rate of increase but 

will not prevent us from eventually reaching the top of the glass, so to speak. Unfortunately, there are only a few choices for energy resources big enough to satisfy future world energy demand. Solar, nuclear and fossil energy are the only resources 

large enough to let a growing world population achieve a standard of living that we 

take for granted in the United States. Eliminating fossil fuels from the mix could 

precipitate a major energy crisis. Thus, it is critical for us to maintain all options 

by developing technologies that allow for the use of carbon-based fuels without leading to the accumulation of carbon dioxide in the atmosphere.1

The goal of a perfectly carbon neutral energy economy is only a slight exaggeration of what is needed; only a small and ever decreasing per capita rate of emissions 

is compatible with a constant concentration of carbon dioxide in the atmosphere. For 

the developed countries, this means reductions in the carbon intensity of their energy systems by much more than 90% by some point in this century. Without such 

reductions, the world would have to settle for far less energy, or an uncontrolled 

rise in the carbon dioxide concentration of the atmosphere. This is true whether the 

world succeeds in stabilizing the carbon dioxide concentration in the air at the currently suggested level of 450 ppm, or fails and ends up stabilizing at a much higher 

level some decades later. In my view, a transition to a carbon neutral economy is 

unavoidable. The question is only how fast we will be able to stabilize the carbon 

dioxide level in the atmosphere, and what pain and what risk the world will accept 

in exchange for a less rapid transition. 

Capture of carbon dioxide from the air and mineral carbonate sequestration are 

two important tools in stabilizing carbon dioxide concentrations without giving up 

on carbon-rich energy sources and carbon-rich fuels like gasoline, diesel, or jet fuel. 

While this committee is considering air capture and mineral sequestration in the 

context of geoengineering, these technologies are very different from other 

geoengineering approaches like albedo engineering or ocean fertilization technologies. They involve far less risk, because they do not attempt to change the dynamics of the climate system, but simply return it to a previous state. Air capture 

and mineral sequestration simply work towards restoring the carbon balance of the 

planet that has been disturbed by the massive mobilization of fossil carbon. Their 

purpose is to capture the carbon that has been mobilized and to immobilize it again. 

Because they function within the existing carbon cycle, they also have far fewer unintended consequences than many other geoengineering approaches. 

Air capture removes carbon dioxide directly from the air. It therefore can compensate for any emission, even emissions that happened in the past. We could theoretically reduce the atmospheric level of carbon dioxide to the pre-industrial level 

(280 ppm) while continuing to use fossil fuels. Mineral sequestration closes the natural geological carbon cycle and immobilizes carbon dioxide by forming stable and 

benign minerals. Both technologies fall into the broader category of carbon dioxide 

capture and storage. Among these technologies, they stand out because they are 

comprehensive. Air capture could cope with all carbon dioxide emissions; mineral sequestration could store all the carbon that is available in fossil fuels. 

Without carbon dioxide capture and storage, the only way to stabilize the carbon 

dioxide concentration of the atmosphere is to abandon coal, oil and natural gas. As 

previously discussed, this option is, in my opinion, not viable or practical. Carbon 
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2K.S. Lackner, H.-J. Ziock, and P. Grimes (1999), Carbon Dioxide Extraction from Air: Is It 

an Option?, presented at Proceedings of the 24th International Conference on Coal Utilization 

& Fuel Systems, Clearwater, Florida, March 8–11, 1999. 

dioxide capture and storage technology offers a way to maintain access to this plentiful and cost-effective energy source, while addressing the biggest environmental 

downside associated with their use. 

In my view, carbon dioxide capture and storage pose two major challenges: how 

to catch the ‘‘fugitive’’ emissions that are not amenable to capture at the source of 

emission and how to deal with the vast amounts of carbon dioxide that will need 

to be stored safely and permanently. 

Air capture can address the myriad emissions from small emitters including cars 

and airplanes and also deal with the last few percent of power plant emissions 

whose escape is expensive to prevent. Other capture options may be advantageous 

for particular situations, e.g., in the flue stack of a power plant, but air capture can 

assure that all emissions can be dealt with. 

Storage of carbon dioxide is difficult. Since carbon dioxide is a gas, it will tend 

to escape from its storage site unless it is chemically converted to a mineral. Over 

this century, the mass of the carbon dioxide that will need to be stored will rival 

the amount of water in Lake Michigan. To avoid the escape of the carbon dioxide 

back into the atmosphere, it becomes necessary to maintain a physical barrier between the gas and the atmosphere, and to assure its efficacy for thousands of years. 

Given the large volumes involved, this raises serious questions about the safety and 

permanence of underground gas storage. These questions can only be answered by 

considering the specifics of each particular site. Quite rightly, the public will demand a careful risk analysis and detailed accounting, which will result in a gradual 

reassessment of the overall capacity of geological storage. I consider it likely that 

current estimates are too optimistic. Nevertheless there will be significant and adequately safe underground storage of carbon dioxide gas because there are some excellent storage sites available, and the technology to use them already exists. However, mineral sequestration may be required to complete the task of carbon sequestration on a longer time scale. Mineral sequestration converts the carbon dioxide 

chemically into a solid mineral that is common and stable in nature. There is no 

possibility of a spontaneous return of the carbon dioxide. Even though mineral sequestration may be more expensive up front, its long-term costs may prove to be 

more affordable.

Air Capture 

The ability to capture carbon dioxide from the air is not new. Every submarine 

and every spaceship needs to remove carbon dioxide from the air inside in order to 

keep the crew healthy. The challenge is not to capture carbon dioxide from the air, 

but to do so in an economically affordable fashion and on a large scale. 

I was the first to suggest that capture of carbon dioxide from the air should be 

considered as a promising approach to managing carbon dioxide in the atmosphere 

and hence to combating climate change.2 Capture from the atmosphere has many 

advantages. First, it separates carbon dioxide sources from sinks, so it makes it possible to collect carbon dioxide anywhere in the world. Air mixes so fast and so thoroughly that capture in the Nevada desert could compensate for emissions in New 

York City, in Mali, in Ghana, or anywhere in the world. In a matter of weeks to 

months after starting to capture carbon dioxide in the Northern Hemisphere, the 

carbon dioxide reduction will have spread out over the entirety of this hemisphere. 

Before starting research in this field, I was struck by two observations that suggested technical feasibility. First, the concentration of carbon dioxide in the air, although usually considered very small, is by some measure surprisingly large. To illustrate this point, consider a windmill, which can be viewed as an apparatus to 

reduce the human carbon footprint by delivering electricity without carbon dioxide 

emissions. For the same amount of electricity from a conventional power plant could 

be made carbon neutral with a carbon dioxide collector. The frontal area of this collector standing in the wind could be more than a hundred times smaller than that 

of a windmill. This convinced me that the cost of scrubbing the carbon dioxide out 

of the air is not in the apparatus that stands in the wind, but rather it is in the 

cost of ‘‘scraping’’ the carbon dioxide back off collector surfaces, so they can be used 

again. Fortunately, the binding strength of these sorbent surfaces need not be much 

stronger than the binding strength of the sorbent materials that would be used in 

a flue stack to scrub the carbon dioxide out of the flue gas. This fact, which follows 

from basic thermodynamics, is surprising considering the three hundred times higher initial concentration of carbon dioxide in the flue gas stream versus in the atmosphere. These insights—based on fundamental physics and thermodynamics—led me 
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3Lackner, K. S. (2009), Carbon of Dioxide Capture from Ambient Air, The European Physics 

Journal: Special Topics, 176(2009), 93–106. 4The 21% is based on the average CO2 emissions in U.S. electricity generation. 

to start a large effort in air capture research, which has been funded by Gary 

Comer, the former owner of Lands End. Much of the work has been performed at 

a small research company (Global Research Technologies) of which I am member, 

a fact that I feel obligated for reasons of transparency to disclose. Much of the research effort is now housed at Columbia University. 

This original R&D effort allowed us to go beyond theoretical arguments of what 

could be done with some ideal sorbent materials. We were able to demonstrate our 

ability to capture carbon dioxide from the air with real sorbents that require very 

little energy both in their regeneration and in the preparation of a concentrated 

stream of carbon dioxide ready for sequestration. We discovered a novel process, 

which we refer to as a moisture swing absorption system. We create air scrubbers 

that load up with carbon dioxide when dry and then release the carbon dioxide 

again when exposed to moisture. 

We have demonstrated the capabilities of this sorbent in public and have published our results.3 In short, our system requires water and electricity to collect carbon dioxide. The water can be saline and the energy consumption of the process is 

such that only 21% of the carbon dioxide captured would be released again at a distant power plant that produces the electricity required in the process.4 Nearly 80% 

of the captured carbon dioxide counts toward a real reduction of carbon dioxide in 

the atmosphere. At this point we have demonstrated the system on the bench scale, 

and are moving toward a one-ton-per-day prototype. Just like a hand-made car will 

be expensive we expect a first of a kind version to capture carbon dioxide at approximately $200 per ton. This cost is dominated by manufacturing and maintenance cost 

and we see significant and large potential for cost reductions. We have set ourselves 

a long term goal of $30/ton of carbon dioxide, or roughly an addition of 25C per gallon to the price of gasoline. While we are not the only ones developing air capture 

technology, we were the first to get started, and we believe we are the closest to 

viable solutions. 

Technical air capture, as opposed to growing biomass in fields, in forests and in 

algae ponds, can operate with a much smaller footprint. A ‘‘synthetic tree,’’ our mechanical device to capture carbon dioxide from the air, collects approximately a 

thousand times as much carbon dioxide as a natural tree of similar size. It is for 

this reason that air capture is of practical interest. 

Just as there are proposed side benefits to industry and the economy from biomass management of carbon dioxide, there are several immediate applications for 

carbon dioxide captured from the air. First, there is a small market of eight million 

tons per year for merchant carbon dioxide (i.e., carbon dioxide that is shipped by 

truck to its customers). Applications range from dry ice production to welding supply and carbonation of drinks. The price of merchant carbon dioxide depends on the 

distance from the nearest source and is often well above $100/ton. This market 

could provide a toehold for air capture technology where it could be tested before 

carbon regulations address climate change issues. Oil companies provide another potential market for air capture. In the United States some forty million tons of carbon dioxide are consumed annually in enhanced oil recovery. 

In the future one can expect a large market for air-captured carbon dioxide in 

managing carbon for climate change. Total emissions in the United States are nearly six billion tons of carbon dioxide per year. Some fraction—currently nearly 

half—of all emissions comes from sources that do not lend themselves to capture 

at the point source. These include emissions from automobiles and airplanes. Indeed, practically all emissions from oil consumption fall into this category. As a result, air capture is the only practical option to maintain access to oil-based energy 

products. Indeed, mitigating the use of liquid hydrocarbon fuels is an important application for air capture. There is no good alternative to liquid fuels, e.g., gasoline, 

diesel or jet fuel. A pound of fuel contains about one hundred times as much energy 

as a pound of battery. 

Air capture remains necessary as long as liquid carbon-based fuels are used in 

the transportation sector. Regardless of the carbon source in the fuel, the carbon 

will end up as carbon dioxide in the air, which will need to be captured. Rather than 

storing the carbon dioxide, it is also possible to recycle its carbon back into fuel, but 

this way of closing the carbon cycle requires renewable or other carbon-free energy 

inputs. Biomass fuels are a special example of closing the carbon cycle. Green plants 

capture carbon dioxide from the air by natural means and with the help of sunshine 

convert it into energy rich carbon compounds. However, the ability of biological systems to collect carbon dioxide from the air is slow. Thus, large-scale fuel production 
172

requires large swaths of land. Indeed, algae growth is limited by the innate ability 

of algae to collect carbon dioxide. And many companies have realized that they could 

improve performance by providing carbon dioxide from other sources. This could be 

carbon dioxide from a power plant, but ultimately one can only close the global carbon cycle if this carbon dioxide comes directly from the air. Air capture would be 

a natural complement to algae production of synthetic fuels. 

Air capture can work for any emission of carbon dioxide, no matter where it occurs. Thus, it can provide the capture of last resort. For most power plants, capture 

at the site is the most economic approach, but in a number of older plants, it may 

be cheaper to collect carbon dioxide from the air or to install scrubbers that can only 

partially remove the carbon dioxide in the flue stack. The remaining fraction would 

still be released to the air and could be compensated for by an equivalent amount 

of air capture. 

Finally, air capture provides one of the few options to drive the carbon dioxide 

content of the air back down. In a sense, here you are capturing carbon dioxide that 

was released decades ago. This is the ultimate separation of sources and sinks not 

only in space but also in time. This ability to turn the clock back, at least partially, 

is important, because it is very difficult to envision a scenario in which the world 

manages to stabilize carbon dioxide concentration so that the total greenhouse gas 

impact is less than that of 450 ppm of carbon dioxide. Adding up all greenhouse 

gases, including for example methane, the world is only seven years away from 

breaching this limit. 

Managing global carbon dioxide emissions is a huge task, but air capture could 

operate at the necessary scale. Right now the technology is still in its infancy, but 

one can already see an outline of how it may work in the future. A collector that 

can produce one ton of carbon dioxide per day would easily fit into a standard fortyfour-foot shipping container. While the first few of these containers will likely cost 

$200K each, we expect the price to come down to that of a typical automobile or 

light truck. 

For the sake of argument, let us assume that air capture units stay at this scale, 

and that they are mass produced like cars. With ten million such units operating, 

air capture would make a significant contribution to the world’s carbon balance. Ten 

million units would collect 3.6 billion tons annually or 12% of the world’s carbon 

dioxide emissions. If these units last ten years, annual production would need to be 

1 million. This is a tiny fraction of the world’s annual production of cars and light 

trucks (approximately 70 million units). Thus, reaching relevant scales would certainly be feasible, although it would require a substantial commitment, and obviously a policy and regulatory framework that support such an effort.

Mineral Sequestration 

Capturing carbon dioxide is just the first step in carbon management. After one 

has the carbon dioxide, it must be permanently stored to prevent it from returning 

to the atmosphere. Columbia University has an active research program on mineral 

sequestration, involving Juerg Matter, David Goldberg, Alissa Park and Peter 

Kelemen. Our group is also working on DOE-sponsored research on monitoring carbon dioxide in underground reservoirs. 

Underground injection, or geological sequestration, is one option for carbon dioxide storage. It seems straightforward and simple, but it does not have an unlimited 

resource base, and it comes with the requirement of maintaining (virtually indefinitely) a seal to keep a gas that naturally wants to rise to the surface safely underground. By contrast, mineral sequestration has a much larger resource base, and 

it results in a stable, benign carbonate material that is common in nature and will 

last on a geological time scale. For all practical purposes, the storage of carbon dioxide in mineral carbonates is permanent. It requires energy to reverse the 

carbonation reaction. Therefore this reversal cannot happen spontaneously. 

Mineral sequestration taps into a very large, natural material cycle on Earth. Volcanic processes push carbon dioxide into the atmosphere, and geological weathering 

removes it as carbonate. Carbon dioxide, which in water turns to carbonic acid, reacts with a base to form a salt. This happens every time it rains. There are plenty 

of minerals to neutralize carbonic acid, but this geological weathering process is 

very slow. Left to its own devices, nature will take on the order of a hundred thousand years to reabsorb and fixate the excess carbon that human activities have mobilized and injected into the atmosphere. The purpose of mineral sequestration in 

managing anthropogenic carbon is to accelerate these natural processes to the point 

that they can keep up with human carbon dioxide releases. 
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5Lackner, K. S., C. H. Wendt, D. P. Butt, J. E.L. Joyce, and D. H. Sharp (1995), Carbon Dioxide Disposal in Carbonate Minerals, Energy, 20(11), 1153–1170. 6For more information, see: http://pubs.usgs.gov/ds/414/. 7To set the scale, $10 per ton of CO2 would add roughly 1 cent to the cost of the electricity 

from a 33% efficient coal fired power plant, it would add 8 cents to the gallon of gasoline. 8Matter, J. M. et al (2009), Permanent Carbon Dioxide Storage into Basalt: The CarbFix Pilot 

Project, Iceland, Energy Procedia, 1(1), 3641–3646. 

There are two fundamentally different approaches to mineral sequestration. The 

first is ex situ mineral sequestration.5 Here one envisions a mine where suitable 

rock, usually serpentine and/or olivine is mined, crushed and ground up, and then 

in an industrial, above-ground processing plant, carbon dioxide is brought together 

with the minerals to form solid carbonates that can then be disposed of as mine 

tailings. Mining operations would be large, but no larger than current mining operations. It would take roughly six tons of rock to bind the carbon dioxide from one 

ton of coal. An above-ground mine producing coal in the Powder River Basin typically has to move ten tons of overburden in order to extract one ton of coal. Therefore, without wanting to minimize the scale of these operations, it is worth pointing 

out that current mining operations to produce coal already operate on the same 

scale. 

The cost of ex situ mineral sequestration is directly related to the time it takes 

to convert base minerals to carbonates. In effect, the reactor has to hold an amount 

of minerals that is consumed during processing time. Thus, a reactor vessel which 

requires a day to complete the process is twenty-four times larger than a reactor 

vessel that finishes the job in an hour. Cost effective implementations must aim for 

a thirty to sixty minute processing time. There are very few minerals that are sufficiently reactive to achieve this goal. The only ones that exist in large quantities are 

serpentine and olivine. A recent study performed by the USGS and two of my students has shown that in United States, the resource base of these minerals is ample 

and could cope with U.S. carbon dioxide emissions.6

Worldwide, these minerals are sufficiently abundant to cope with all the carbon 

dioxide that could be produced from the entire fossil fuel resource. 

Somewhat surprisingly the cost of mining and managing the tailings is quite affordable; estimates are below $10 per ton of carbon dioxide.7 The cost that still 

needs to be reduced is the cost of the neutralization or carbonation reaction. In nature the chemical processes are slow and accelerating them either costs energy 

(which is self-defeating as it leads to more carbon dioxide emissions) or money. 

Today, total costs are estimated around $100 per ton of carbon dioxide, which makes 

costs roughly five times higher than they would need to be for a competitive process. 

Overcoming a factor of five in costs sounds challenging, but most alternative forms 

of energy still have high costs or started out with costs that were even further away 

from what would be required in a competitive market. 

The second approach to mineral sequestration is in situ mineral sequestration. In 

this case the carbon dioxide is injected underground just as it is in geological storage, but for in situ mineral sequestration, the site has been carefully selected so 

that the carbon dioxide will react with the local mineral rock and form carbonates 

underground. The result will be carbonates that form solids, or in some case remain 

dissolved in the pore water deep underground. For this to be useful, the reactions 

will have to bind all or most of the carbon dioxide on a time scale that is suitable 

for human decision making. If it takes more than a few decades for the carbon dioxide to bind, the carbonation process comes too late to affect human decision making. 

Nevertheless, a few decades is a lot longer than thirty to sixty minutes, which is 

the time limit for an above ground reactor used for ex situ mineralization. As a result, a larger variety of minerals are available for in situ mineral sequestration than 

for ex situ mineral sequestration. Of particular interest are basalt formations. At 

Columbia University we have tested this in our own backyard on the Palisades 

along the Hudson River. On a larger scale in the U.S. North West, the Columbia 

River Basalts provide an inexhaustible resource base for in situ mineral sequestration. The Earth Institute is also involved in an in situ demonstration project in Iceland called the CarbFix project, as Iceland boasts some of the freshest and therefore 

most reactive basalt formations in the world.8

Mineral sequestration could play an important role in carbon management, if 

R&D could drive the cost down. First, mineral sequestration would provide a very 

different alternative for storing carbon dioxide that would provide a more permanent and potentially safer method than geological storage. The uncertainties in geological storage may well result in a general downgrading of the resource estimates, 
174

9Lackner, K. S., and S. Brennan (2009), Envisioning Carbon Capture and Storage: Expanded 

Possibilities Due to Air Capture, Leakage Insurance, and C-14 Monitoring, Climate Change, 

96(3), 357–378. 

leaving only remote and particularly well characterized storage sites.9 For example, 

underground storage of carbon dioxide in seismically active areas is almost certainly 

going to be challenged by nearby communities due to public safety concerns. Luckily, California has very large serpentine deposits and could entirely rely on mineral 

sequestration. 

Second, particularly ex situ mineral sequestration may provide a virtually unlimited supply of carbon dioxide storage capacity and thus could act as an assurance 

that access to fossil fuels is not at risk. Mineral sequestration raises the value of 

the U.S. coal reserves because it assures that they could be used if they are needed. 

Otherwise, the resource limitations on fossil fuels may not be the carbon in the 

ground, but the capacity of the atmosphere to accept the carbon dioxide. The world 

resource base in coal, tars, shales, and, potentially, in methane hydrates is so large 

that the accumulation of carbon dioxide in the atmosphere will need to be addressed. 

Third, mineral sequestration makes accounting simple and it provides a high degree of assurance that the carbon storage is, for all practical purposes, permanent. 

The environmental footprint is contained to the site and to the time window in 

which the mine operates.

Combining Mineral Sequestration and Air Capture 

It has been suggested that one could combine mineral sequestration and air capture into a single process. For example, one could use olivine or serpentine minerals 

as soil enhancers and rely on the soils to remove additional carbon dioxide from the 

air in a typical geological weathering reaction. Alternatively, it is possible to spread 

these minerals into the ocean, and let the reaction between the ocean and the carbon dioxide from the air happen spontaneously to neutralize the additional base. 

I do not advocate such an approach, because I see major challenges with distributing that much material over large distances. For the same reason, I believe that 

in ex situ mineralization the serpentine has to be processed at the serpentine mine. 

There are several options: the coal plant could be collocated with the serpentine 

mine with the coal would shipped in; the carbon dioxide could be pipelined from a 

remote power plant to the serpentine mine; or the carbon dioxide could be captured 

from the air directly at the mine site. In no case, would the heavy serpentine rock 

have to move over large distances, because the shipment of large amounts of solid 

material is too expensive. 

Furthermore, I see unnecessary environmental complications with distributing 

finely ground rock in the environment. Mineral rocks, when ground finely, represent 

environmental and health hazards, which are better dealt with in the confines of 

a mining operation rather than in open fields of enormous extended areas. Finally, 

these soil enhancers or ocean fertilizers will, by their very nature, change the ecological balance in the areas to which they are applied. 

One of the major advantages of air capture and mineral sequestration is that both 

operations can be performed on a well contained and relatively small footprint. 

Thus, one can limit the environmental impacts to small areas and keep them well 

contained.

The Research Agenda 

One of the major challenges facing mankind is to provide ample energy without 

destroying the environment. The energy sector is exceptional in that the problems 

we face cannot be solved by simply promulgating the state of the art worldwide. 

With state of the art technology in water and food the world would be assured plenty fresh water and plenty of food. However, the state art in energy is based on fossil 

fuels without carbon management, and its continued growth would wreak environmental I havoc. While there is reason to believe that technologies for carbon management can be developed, they have not been developed yet, and thus it is necessary to create a large and ambitious research agenda. 

Stabilizing carbon and providing energy is a century scale problem. It is not just 

about retrofitting existing plants, but it is about developing a brand new energy infrastructure. The power plant of the future will be different from conventional 

plants of today. Success will require a portfolio from basic research to commercial 

applications. Learning by doing will not happen until we actually do build a new 

infrastructure. 

Most of the immediate research agenda does not fit with the goals and aspirations 

of a company in the private sector. Since there is no market for carbon reduction 
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in the absence of regulation, it is difficult to appeal to a profit motive. However, 

since there is no accepted technology to solve the problem, it is difficult to force new 

power plant designs through regulation. Thus, public R&D must make major contributions to solve the problem of carbon dioxide emission and demonstrate feasibility. 

There are very few resource pools for providing the amount of energy that the 

world will need in the second half of the twentieth century. The only sources big 

enough are solar energy, nuclear energy and fossil fuel energy combined with carbon 

capture and storage. In developing a sustainable energy platform, the world will 

need to place a big bet on all three options and hope that at least one of these bets 

pays off. In the unlikely event that all three resources fail to become sustainable 

and affordable energy resources, the world will be hit by an energy crisis of unprecedented proportions. Developing these alternatives will take a long time and the second half of the twentieth century is not that far away. The world has been working 

for more than fifty years on alternatives to fossil fuels—so far without success. 

R&D will need to span the gamut from basic research to testing out new pilot 

plants, and from physics to health sciences. Nearly by necessity, research will span 

agencies from the National Science Foundation to the Department of Energy, from 

National Institute of Standards and Technology to the Environmental Protection 

Agency. Energy is important enough that it should be woven into nearly all aspects 

of technology development. Specific to air capture and mineral sequestration, research needs to focus on better sorbents, reaction kinetics, carbonate chemistry, and 

catalysts to speed up reactions. In applied research, we should consider applications 

in which carbonate disposal could become a byproduct of mineral extraction. We 

need to find better ways of producing carbonates from serpentines, and develop advanced capabilities of modeling the weathering of basalts in the presence of carbon 

dioxide. Demonstrations of the technology are necessary if they are ever to be introduced in the market. Altamont Pass was able to convince the world that wind energy has a future. Imagine what a large air capture park could do to convince the 

world that capturing carbon dioxide from the air is both possible and practical.

BIOGRAPHY FOR KLAUS LACKNER

Klaus Lackner is the Ewing Worzel Professor of Geophysics at Columbia University, where he is also the Director of the Lenfest Center for Sustainable Energy, the 

Chair of the Department of Earth and Environmental Engineering, and a member 

of the Earth Institute faculty. Lackner’s current research interests include carbon 

capture and sequestration, air capture, energy systems and scaling properties (including synthetic fuels and wind energy), energy and environmental policy, lifecycle 

analysis, and zero emission modeling for coal and cement plants. 

Lackner’s scientific career started in the phenomenology of weakly interacting 

particles. While searching for quarks, he and George Zweig developed the chemistry 

of atoms with fractional nuclear charge. He participated in matter searches for particles with a non-integer charge in an experiment conducted at Stanford by Martin 

Perl and his group. After joining Los Alamos National Laboratory (LANL) in 1983, 

Lackner became involved in hydrodynamic work and fusion-related research. He 

was a scientist in the Theoretical Division, but also an active part of the Laboratory’s upper management. He was instrumental in forming the Zero Emission Coal 

Alliance and was a lead author in the IPCC Report on Carbon Capture and Storage. 

In 2001, Lackner joined Columbia University and, in 2004, became a member of 

Global Research Technologies, LLC. 

Lackner earned his degrees from Heidelberg University, Germany: the Vordiplom, 

(equivalent to a B.S.) in 1975; the Diplom (or M.S.) in 1976; and his Ph.D. in theoretical particle physics, summa cum laude, in 1978. He was awarded the ClemmHaas Prize for his outstanding Ph.D. thesis at Heidelberg University. Lackner held 

postdoctoral positions at the California Institute of Technology and the Stanford 

Linear Accelerator Center before beginning his professional career, and he attended 

Cold Spring Harbor Summer School for Computational Neuroscience in 1985. 

Lackner was also awarded the Weapons Recognition of Excellence Award in 1991 

and the National Laboratory Consortium Award for Technology in 2001. 

Chairman BAIRD. Thank you, Dr. Lackner. 

Dr. Jackson. 
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STATEMENTS OF DR. ROBERT JACKSON, NICHOLAS CHAIR OF 

GLOBAL ENVIRONMENTAL CHANGE, PROFESSOR, BIOLOGY 

DEPARTMENT, DUKE UNIVERSITY 

Dr. JACKSON. Chairman Baird, Chairman Gordon and others, 

thank you for your attention today. Let me begin by stating that 

a wealth of evidence already shows our climate is changing and is 

a threat to people and organisms. As a scientist and citizen of our 

great Nation, I urge you to act quickly to reduce greenhouse gas 

emissions. So far today, you have heard about several approaches 

for geoengineering the earth’s climate. My task is to discuss biological and land-based strategies. 

My first take-home message is that some geoengineering on land 

is already feasible, including restoring or planting forests, avoiding 

deforestation and using crops to store carbon in soils and reflect 

sunlight. Plants are one of the cheapest ways to remove carbon 

from our air. Several limitations in land-based approaches are 

worth mentioning. One is that we need to apply these strategies 

over millions of acres to play a meaningful role. 

The second is money. Private landowners will need incentives to 

apply geoengineering. How much will these incentives cost and how 

sustained will the landowners’ responses be? 

A third limitation is that geoengineering will surely alter other 

resources we value, including water and biodiversity. One difference for geoengineering on land is that carbon removal and sunlight reflections both change, never just one or the other. 

Geoengineering also alters other factors that affect temperature. 

We need a new framework that includes a full accounting for 

greenhouse gases and biophysics together. That long-term framework should include water evaporation, energy exchange and other 

factors in addition to carbon dioxide and sunlight. 

Consider this example. Imagine providing incentives for tree 

planting on former croplands or pasture. This activity will remove 

carbon from air as the trees grow. What about the same activity 

viewed from the standpoint of solar radiation management? Trees 

tend to be darker than grasses or crops and to absorb more sunlight. The same plantation that cools the earth by removing carbon 

could warm it by reflecting less light. Your new plantation affects 

the earth’s temperature in other ways too. Trees typically use more 

water than other plants. This increases evaporation, cools land locally, loads energy into the atmosphere and can produce clouds 

that absorb or reflect sunlight and produce rain. Overall, such biophysical changes can affect climate more than carbon removal does 

and sometimes in a conflicting way. 

New research is needed on a full accounting system for greenhouse gases and biophysics, particularly in climate models. Some 

gaps in scientific understanding include the ways the models resolve cloud cover, melt snow, supply water for plant growth and 

simulate the planetary boundary layer. The fusion of real-world 

data and models is critical for reducing these uncertainties. 

Our lands do more than store carbon and protect climate. They 

supply water, detoxify pollutants, support life and produce food. 

Geoengineering on land will alter the abundance of many things we 

value. We need research on its full environmental effects. 
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In the best-case scenario, geoengineering activities can help the 

environment. Restoring habitats or avoiding deforestation will store 

carbon, slow erosion, improve water quality and provide habitat for 

wildlife. In a worst-case scenario, geoengineering will harm ecosystems, such as proposals to cover deserts with reflective shields. 

In most cases, we will have to choose which services we value most. 

Returning to our plantation example, forests store more carbon 

than grasslands but also use more water. Yearly stream flow often 

drops by half after planting and streams can dry up completely. 

Which is worth more: carbon or water? The answer likely depends 

on whether you live in a water-rich area, as I do, or a water-poor 

one. Unfortunately, you can’t have your cake and drink it too. 

A new interdisciplinary research agenda for geoengineering 

drafted by a panel of experts is urgently needed. This process 

should be open and seek input from any stakeholders. Because no 

federal agency has the expertise to lead geoengineering alone, a coordinated working group is the best solution. I recommend that the 

U.S. Global Change Research Program [USGCRP], comprised of 13 

departments and agencies, lead this effort. 

In conclusion, although emitting less carbon dioxide and other 

greenhouse gases should remain our first priority, we do have 

short-term opportunities on land. In general, though, we need to 

study the feasibility, cost and environmental co-effects before applying geoengineering broadly. We need to get geoengineering right 

as a tool of last resort. Thank you. 

[The prepared statement of Dr. Jackson follows:]

PREPARED STATEMENT OF ROBERT JACKSON

Biological and Land-Based Strategies for Geoengineering Earth’s Climate

Chairman Baird and other members of the Science and Technology Committee, 

thank you for the chance to testify today. I appreciate the opportunity and your attention. 

Let me first state that a wealth of scientific evidence already shows that climate 

change is happening and presents a grave threat to people and other organisms. We 

need to act quickly. The safest, cheapest, and most prudent way to slow climate 

change is to reduce greenhouse-gas emissions soon. No approach—geoengineering or 

otherwise—should lead us from that path. 

Unfortunately, the world has so far been unable to reduce greenhouse-gas emissions in any substantive way. We therefore need to explore other tools to reduce 

some of the harmful effects of climate change. That is why we are discussing what 

was once purely science fiction—the remarkable possibility of geoengineering 

Earth’s climate. 

For my testimony, you asked me to discuss biological and land-use-based strategies for geoengineering. Here are four take-home messages of my testimony:

1) Some biological and land-use strategies for geoengineering are already feasible, including restoring or planting forests, avoiding deforestation, and 

using croplands to reflect sunlight and store carbon in soils. 

2) Biological and land-based geoengineering alters carbon uptake, sunlight absorption, and other biophysical factors that affect climate together. 

3) Geoengineering for carbon or climate will alter the abundance of water, biodiversity, and other things we value. 

4) A research agenda for geoengineering is urgently needed that crosses scientific disciplines and coordinates research across federal departments and 

agencies.

Let me begin by describing some of the most common biological and land-usebased strategies for geoengineering and their relative effectiveness and feasibility.
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Biological and Land-Based Options for Geoengineering 

As described in the recent Royal Society report, Geoengineering the Climate, many 

geoengineering options are possible. One set of activities focuses on carbon dioxide 

removal. The other examines how to manage systems to reflect sunlight and cool 

the planet, termed solar radiation management. I will call these approaches ‘‘carbon’’ and ‘‘climate’’, respectively. For biological and land-based sequestration, what 

constitutes ‘‘geoengineering’’ instead of ‘‘carbon mitigation’’ or ‘‘offsets’’ is sometimes 

unclear. I will try to focus on strategies that are usually placed in the realm of 

geoengineering. An example of a land-use strategy that is not usually considered as 

geoengineering is the production of biofuels (in the absence of carbon capture and 

storage). I do not have the space to consider biofuels in this brief discussion.

Biological Carbon Dioxide Removal 

Biological and land-based strategies provide a meaningful opportunity to remove 

carbon from the atmosphere and to store it on land. Since 1850, human activities 

accompanying land-use change have released at least 150 gigatons (1015 g) of carbon 

to the atmosphere, roughly one fifth of the total amount of carbon in the atmosphere 

today. 

Plants and other photosynthetic organisms (hereafter ‘‘plants’’) provide one of the 

oldest and most efficient ways to remove carbon dioxide from our air. For this reason, they provide a feasible, relatively cheap way to reduce the concentration of carbon dioxide in the Earth’s atmosphere—at least in the short term. 

Several biological and land-based approaches are possible for removing carbon dioxide from air. Because carbon is lost when a forest is cut or disturbed, restoring

forests is an important tool for placing carbon back in lands. Afforestation, or planting trees in places that were not previously forested (or have not been for many 

years) is another way to remove carbon from the atmosphere. Avoided deforestation

is a third tool that improves the carbon balance and is sometimes considered to be 

geoengineering. If a policy incentive keeps a rainforest in Amazonia or Alaska from 

being cut, carbon that would have moved to the atmosphere is ‘‘removed’’ from the 

atmosphere. 

Restoring and enhancing soil organic matter is another tool for carbon management and removal. Because agriculture tends to release soil carbon to the atmosphere, typically soon after land conversion, incentives to restore native ecosystems 

or to improve agricultural management are two ways to remove carbon from the atmosphere. Restoring or enhancing the amount of organic matter in soil has many 

benefits, including improved fertility and crop yield, reduced erosion, and better 

water-holding capacity. 

Three issues or limitations in biological or land-based geoengineering are important. One is the scale of the approach needed to reduce the amount of carbon in 

our air. For any given project, a single acre of land can be managed or manipulated 

to remove carbon. Nationally, however, we need to implement these strategies over 

millions of acres if they are to play a meaningful role in policy (remembering that 

we already manage millions of acres). Otherwise, their net effect will be too small 

compared to the amounts of carbon entering the atmosphere through fossil fuel 

emissions. 

A second issue is landowner behavior. Land is a valuable commodity, and private 

landowners will need financial incentives to make geoengineering a reality. How 

much will these incentives cost, and under what conditions, financial or otherwise, 

might they change their minds? 

A third issue is that biological and land-based management will inevitably alter 

other resources that we care about, including water and biodiversity. I will return 

to this point after exploring solar radiation management as a second type of 

geoengineering.

Solar Radiation Management 

Managing solar radiation directly is an alternative to removing carbon dioxide 

from air. In effect these approaches manipulate ‘‘climate’’ directly, or at least temperature. The most common approach for cooling is reflecting sunlight back into 

space. You only have to reflect a small percentage of the sun’s rays to counterbalance the temperature effects of a doubling of atmospheric carbon dioxide. Managing solar radiation is thus the basis for many geoengineering strategies, including 

stratospheric dust seeding and whitening clouds over the oceans. 

Biological and land-based strategies can also employ solar radiation management. 

One approach is to select crops, grasses, and trees that are ‘‘brighter’’ in color, reflecting more sunlight into space. This strategy can cool plants locally and save 

water but will likely reduce plant yields in some cases. The option may be especially 

valuable in sunny, dry areas of the world. 
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Like strategies for carbon removal, solar radiation management will need to be 

applied across large areas to be effective, probably millions of acres, at least. One 

smaller-scale exception may be when solar radiation manipulations reduce the energy needed to heat or cool buildings. Urban forestry, white buildings, and ‘‘green 

roofs’’ are examples. The energy savings are local but could play a small but meaningful role in reducing our national energy budget. 

A disadvantage of solar radiation management is that it offsets only the climate 

effects of increased greenhouse gases but does not reduce greenhouse gas concentrations. It does nothing for the pressing problem of ocean acidification, for instance, 

caused by increased carbon dioxide dissolving into our oceans. Also, changing the 

amount of sunlight alters not just temperature but atmospheric circulation, rainfall, 

and many other factors. Less sunlight will almost certainly mean less rainfall globally and is likely to reduce global productivity of plants and phytoplankton.

Geoengineering on Land is Carbon and Climate Management

As just discussed, geoengineering strategies are typically lumped into two categories, those that remove carbon from the atmosphere and those that manage solar 

radiation (‘‘carbon’’ and ‘‘climate’’, respectively). Unlike some geoengineering strategies, however, every biological and land-based approach will alter carbon storage 

and sunlight absorption. Moreover, sunlight is not the only factor that changes the 

temperature and energy balance of an ecosystem. 

We need a new framework for geoengineering that includes a full radiative accounting for greenhouse-gas and biophysical changes together. That 

long-term framework should include not just reflected sunlight but water evaporation, energy exchange, and other important biophysical factors. Such a framework 

will then help us make best-practice recommendations for if, when, and where to 

promote geoengineering activities. 

To demonstrate the need for better accounting, consider the following example. 

Imagine providing landowners with incentives to plant trees on lands that were previously croplands or pasture. Under a carbon management framework, this activity 

will almost certainly remove carbon dioxide from our air (assuming that planting 

and management practices do not increase net greenhouse gas emissions). That is 

what trees do—they grow. 

What about the same activity viewed from the standpoint of solar radiation management or ‘‘climate’’? Trees tend to be darker than grasses or other crop species 

and thus reflect less sunlight (Figure 1; Jackson et al. 2008). The same plantation 

that cools the Earth through carbon removal may warm it by absorbing more sunlight. Planting dark trees in snowy areas could cause substantial warming, for instance. 

Your new plantation in Figure 1 also affects the Earth’s temperature in more 

ways than just storing carbon and reflecting less sunlight. Trees typically evaporate 

more water than the grasses or other crops they replace do. This increased evaporation (the blue arrows in Figure 1) cools the land locally. It also loads more energy 

into the atmosphere and can alter the production of convective clouds that absorb 

or reflect sunlight and produce rain. Trees also alter the roughness or unevenness 

of the plant canopy, transmitting more heat into the atmosphere (the red arrows 

in Figure 1). Overall, such biophysical changes can affect local and regional climate 

much more than the accompanying carbon sequestration does—and sometimes in a 

conflicting way.
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New research is needed to provide a full radiative accounting for greenhouse-gas 

changes and biophysics together. Some examples of gaps in scientific understanding 

include the ways that climate models do (and don’t) resolve cloud cover, melt snow, 

supply water for plants to grow, and simulate the planetary boundary layer. The 

fusion of observations and models is critical for reducing these uncertainties.

Geoengineering for Carbon or Climate Will Alter Other Valuable Resources 

As just described, our lands do many things for us. They store carbon and protect 

our climate. They also supply and purify water, detoxify pollutants, support a treasure of biodiversity, and produce the food we need to survive. Geoengineering strategies to remove carbon from our air or to reflect sunlight will inevitably change the 

abundance of these resources. We need immediate research on the full environmental effects of geoengineering.

In a best-case scenario, managing lands to store carbon or reflect sunlight will 

provide additional ecosystem benefits. An example of this win-win scenario is restoring degraded lands. Restoring forests or native grasslands on lands that have been 

over-used will not just store carbon in plants and the soil; it will slow erosion, improve water quality, and provide habitat for many species. Similarly, avoiding deforestation in the tropics keeps carbon out of the atmosphere, preserves biodiversity, 

and provides abundant water for streams and for the atmosphere to be recycled in 

local storms. 

In a worst-case scenario, blindly managing lands to store carbon or reflect sunlight will harm ecosystem goods and services. Covering hundreds or thousands of 

square miles of deserts with reflective surfaces, as has been proposed, may indeed 

cool the planet. It would also harm many other ecosystem services we value. 

The more common reality will lie somewhere in between. One example of a tradeoff in services that I have studied is carbon storage and water supply. Continuing 

the analogy in Figure 1, most trees store carbon for decades after planting. Because 

they grow quickly, however, trees also use more water than the native grasslands 

or shrublands they replace (Figure 2; Jackson et al. 2005). These losses are substantial. Yearly streamflow typically drops in half soon after planting. In about one in 

ten cases the streams dry up completely.
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In many real-world scenarios, we will have to choose which ecosystem 

services we value most. In the specific case of our plantation, which currency 

should we value more—carbon or water? The answer probably depends on whether 

you live in a relatively water-rich area or a water-poor one. Unfortunately, you can’t 

always have your cake and drink it, too. 

Research into the environmental co-effects of geoengineering is critical for successful policy and for avoiding surprises. In the final section of this testimony, I present 

a few ideas for designing and coordinating geoengineering research.

Which U.S. Agency Should Lead Geoengineering Research? 

Because of the range of geoengineering activities and their environmental consequences, no single agency has the expertise needed to lead all geoengineering research. A more feasible approach would build on a model that is sometimes used 

successfully—a coordinated, interagency working group. One example of such a 

group is the U.S. Global Change Research Program comprised of thirteen departments and agencies. 

Choosing a single U.S. agency to lead the research effort is appealing administratively but would duplicate efforts. The Environmental Protection Agency might be 

one home for geoengineering research, particularly if the EPA is to regulate carbon 

dioxide emissions. The Department of Agriculture, including its Forest Service and 

Agricultural Research Service, has a long history of expertise in managing our forests and agricultural lands. The Department of Energy leads federal agencies in lifecycle and energy analysis on the global carbon cycle. The National Aeronautics and 

Space Administration (NASA) coordinates satellite-based research needed to understand global processes and feedbacks. Many other agencies, including the National 

Science Foundation, the National Oceanic and Atmospheric Administration, and the 

Department of the Interior, play important roles in research. 

Geoengineering research is most likely to succeed if research agencies agree on 

a joint research agenda. The agencies should therefore immediately convene 

a multi-disciplinary panel of experts to outline an agenda for 

geoengineering research. This process must be open and should seek input from 

the broader research community and from stakeholders outside that community.

Conclusions 

To discuss the possibility of engineering the Earth’s climate is to acknowledge 

that we have failed to slow greenhouse gas emissions and climate change. Emitting 

less carbon dioxide and other greenhouse gases should remain our first goal. 

Because our climate is already changing, we need to explore every tool to reduce 

the harmful effects of those changes. Geoengineering is one such tool. We have some 

valuable, short-term opportunities at hand, including restoring ecosystems and 

avoiding deforestation. Overall, though, we need to study the feasibility, cost, and 
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environmental co-effects of geoengineering broadly before applying it across the 

United States and the world. We need to get geoengineering right—as a tool of last 

resort.

References 

Royal Society 2009 Geoengineering the climate: science, governance, and uncertainty. RS Policy document 10/09, The Royal Society, London.

Jackson, RB, JT Randerson, JG Canadell, RG Anderson, R Avissar, DD Baldocchi, 

GB Bonan, K Caldeira, NS Diffenbaugh, CB Field, BA Hungate, EG Jobba ́gy, 

LM Kueppers, MD Nosetto, DE Pataki. 2008. Protecting climate with forests. 

Environmental Research Letters 3: 044006, doi:10.1088/1748-9326/3/4/044006.

Jackson RB, EG Jobba ́gy, R Avissar, S Baidya Roy, D Barrett, CW Cook, KA Farley, 

DC le Maitre, BA McCarl, B Murray 2005 Trading water for carbon with biological carbon sequestration. Science 310:1944-1947.

BIOGRAPHY FOR ROBERT JACKSON

Robert B. Jackson is the Nicholas Professor of Global Environmental Change at 

Duke University and a professor in the Biology Department. His research examines 

how people affect the earth, including studies of the global carbon and water cycles 

and climate change. 

Jackson received his B.S. degree in Chemical Engineering from Rice University 

(1983). He worked four years for the Dow Chemical Company before obtaining M.S. 

degrees in Ecology (1990) and Statistics (1992) and a Ph.D. in Ecology (1992) at 

Utah State University. He was a Department of Energy Distinguished Postdoctoral 

Fellow for Global Change at Stanford University and an assistant professor at the 

University of Texas before joining the Duke faculty in 1999. He is currently Director 

of Duke’s Center on Global Change. In his quest for solutions to global warming, 

he also directs the Department of Energy-funded National Institute for Climate 

Change Research for the southeastern United States and co-directs the Climate 

Change Policy Partnership, working with energy and utility corporations to find 

practical strategies to combat climate change. 

Jackson has received numerous awards, including a 1999 Presidential Early Career Award in Science and Engineering from the National Science Foundation (honored at the White House), a Fellow in the American Geophysical Union, and inclusion in the top 0.5% of most-cited scientific researchers (http://

www.isihighlycited.com/). His trade book on global change, The Earth Remains Forever, was published in October of 2002. He has also written two children’s books, 

Animal Mischief and Weekend Mischief, both published by Boyds Mills Press, the 

trade arm of Highlights Magazine. Jackson’s research has been covered in various 

newspapers and magazines, such as the Boston Globe, Washington Post, U.S.A. 

Today, New York Times, Scientific American, Economist, and BusinessWeek, and on 

national public radio. He conceived and organized the Janus Fellowship, an annual 

undergraduate award to encourage the study of an environmental problem from diverse perspectives; 1999’s first recipient traveled down the Nile River to examine 

water use and water policy in Egypt.

DISCUSSION

Chairman BAIRD. Thank you, gentlemen. I commend you for 

keeping your comments in the time period. That enabled us to hear 

all of your initial testimony. We have about probably seven or eight 

minutes until we need to leave. Then what we will do is, we will 

proceed with questions. I will probably ask the first one and I 

imagine we will have to break after that. 

ECONOMIC COSTS OF GEOENGINEERING

I think your points are well taken about that we need to prepare 

for this, but it also well taken that we don’t want to have people 

believe oh, hey, we don’t have to do anything to reduce, and you 

have spoken a lot about carbon. Obviously there are many other 

greenhouse gases of great concern, some much more potent in their 
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efficacy and greenhouse warming. The cost issue seems to me to be 

so prohibitive relative to all the other things we could do more 

promptly to reduce carbon. If you look at conservation, for example, 

if you look at development of alternative energies, if you look at the 

CCS cost curve, and I know carbon sequestration is different than 

what you are talking about, but it would seem to me that your 

technology may be fairly more expensive than carbon capture and 

sequestration. Educate me. Is it or is it not more expensive, and 

if so, why or why not? 

Dr. KEITH. I think it is crucial to distinguish these two completely different kinds of things. Carbon removal is inherently expensive. We can disagree about exactly how much but it is expensive. Putting sulfates in the stratosphere is potentially so cheap 

that costs are irrelevant. In the same sense as when you think 

about security strategy, the actual cost of nuclear warheads is not 

a big driver in security strategy. Costs are so cheap that the richest 

people on the planet could perhaps afford to buy an Ice Age and 

that individual small states could act alone. So essentially that 

doesn’t mean you should do it but it means that this will be a 

risk——

Chairman BAIRD. How cheap is that? Educate us on that. 

Dr. KEITH. Pardon? 

Chairman BAIRD. You are saying it is so cheap. What is it that 

makes it so cheap? 

ATMOSPHERIC SULFATE INJECTIONS

Dr. KEITH. The underlying physical fact that makes it so cheap 

is that a couple of grams of sulfur in the stratosphere offsets a ton 

of CO2 in the atmosphere, not in terms of all the environmental effects, but in terms of the crude radiative forcing. So I am working 

with one of the leading contractors of high-altitude aircraft in the 

United States, Aurora Flight Sciences. We are in the middle of a 

contract they have with us looking at the cost of doing this, and 

the costs are, as we thought, small. 

Chairman BAIRD. Would you add it to the fuel or would it—— Dr. KEITH. No, no, no, that doesn’t work at all. That is in the 

blogosphere. No, you build custom aircraft that would fly at about 

65,000, 75,000 feet. They would put the appropriate sulfur or whatever it is in the atmosphere. And the costs of doing that really 

work out to be low enough that costs don’t matter. We are talking 

about a cost offset the entire effect of doubled CO2. That is an order 

of just billions a year, so that is 100 to 1,000 times cheaper than 

the cost——

Chairman BAIRD. When you say offset the entire effects of 

CO2——

Dr. KEITH. In terms of gross rate of forcing. As I have said and 

we all have said, it can’t solve all the problems. 

Chairman BAIRD. Only on the radiative side? 

Dr. KEITH. Yes. 

Chairman BAIRD. This would have—my guess, I may be 

wrong—would have no impact on ocean acidification. 

Dr. KEITH. None at all. 

Chairman BAIRD. And I think it is really important to understand that. 
184

Dr. KEITH. Absolutely. So this is inherently imperfect. It can’t 

compensate for CO2 in the air completely but it can provide an extraordinarily fast-acting thing, and this business of it being cheap 

I think is pretty much a fact, and it is not necessarily a good thing. 

The downside is, it allows unilateral action. 

Chairman BAIRD. How long does it last up there? 

Dr. KEITH. The lifetimes are years, a couple years. 

Chairman BAIRD. And then it, what, precipitates out or——

Dr. KEITH. Yeah, that is correct. 

Chairman BAIRD. No toxic side effects that we know of? 

Dr. KEITH. The thing we always wonder about is the unknown 

unknown, so if you are thinking about, say, the acidification, it is 

clear that is not a problem in several studies that showed that. But 

of course, the concern here is with so little research there may be 

some unknown unknown that comes out of left field that bites us. 

LAND-BASED GEOENGINEERING

Dr. JACKSON. There may be. There are issues that have come up 

in the literature including interactions with the ozone layer, the 

water cycle and things like that, and I agree with David: more research is necessary. In my group, we do work on both geologic sequestration, CCS sequestration and land-based, and I would say it 

is useful to remember the land-based strategies are much cheaper 

than carbon capture and storage strategies. The issue with landbased strategies is that on a 50- to 100-year time frame, the bucket 

is not big enough to solve this problem. So my answer would be, 

there are some shorter term options that we can do some good and 

we can also do some harm, but there are relatively low-cost options 

that we can use to help us get started. Long term, we need these 

bigger-picture solutions like others here have talked about. 

Chairman BAIRD. Dr. Lackner? 

CARBON AIR CAPTURE AND MINERAL SEQUESTRATION

Dr. LACKNER. Let me make a case for the more expensive carbon 

capture and storage options, which all of them are. My point in a 

way is that air capture is probably more expensive than any other 

capture, but not much more expensive so they are all in the same 

ballpark. Yes, it is correct that it is cheaper to put some conservation in place, to drive efficiency up and all of this. But consider I 

came from New York this morning and I could have said, it is 

much cheaper to walk so maybe I should buy myself some running 

shoes and get going. But in the end I broke down and said the distance is so large, I will buy myself an airplane ticket and fly down 

here. And so I would argue the same is true here too. We can make 

a difference by efficiency, by conservation and doing all of these 

things, but in the end, if you want to keep the level in the atmosphere constant at any number, once you got to that number you 

really have to drive emissions close to zero, and keep in mind with 

the rest of the world growing, basically you have to come down by 

factors of 20 to 30 in order to hold things in a semblance of stability and that requires more drastic solutions. They in the end will 

cost a little more, and you are closing the carbon loop by adding 

another third to it. 
185

Chairman BAIRD. Thank you. We are going to recess at this 

point. My belief is, we have most likely at least an hour of votes, 

so we will resume the hearing at 11:30 and with the indulgence of 

our guests and our panelists, I apologize for the interruptions but 

we don’t get to set that part of the schedule. Thanks. We will see 

you in an hour. 

[Recess.] 

PUBLIC OPINION AND EDUCATION

Chairman BAIRD. I thank you for your indulgence on this hour 

break. I will recognize Mr. Inglis in a minute. I will share with you, 

though, this idea of placing particles in the upper atmosphere. Are 

any of you familiar with the conspiracy theory known as 

chemtrails? Have you heard of this? It is a rather interesting phenomenon. I was at a town hall and a person opined that the shape 

of contrails was looking different than it used to, and why was 

that? I gave my best understanding of atmospheric temperature 

and humidity and whatnot, but the theory which is apparently 

pretty prevalent on the Net is that the government is putting psychotropic drugs of some sort into the jet fuel and that is causing 

a difference in appearance of jet fuel and allowing them to secretly 

disseminate these foreign substances through the atmosphere via 

our commercial jet airline fleet. Thanks to Dr. Keith, I know that 

is true. The blogs will have your name, Dr. Keith. I am just kidding. 

But it does—on a more serious note, it does highlight that if we 

are going to do this, we are going to have to be very clear with the 

public about what we are doing and how we are doing it and why 

we are doing it and unintended consequences, because legitimate 

scientific research must not get tied up into these kind of things. 

Dr. Keith? 

Dr. KEITH. I think it is really crucial to do it in a transparent 

way. One of the reasons I think we need a small government program now is to inject some transparency because right now we 

have got a hodgepodge, including private money, and that increases 

the risk that people are very fired up about this. I have voice mails 

from people who told me I am going to burn in a lake of fire and 

I don’t love my kids and I am a murderer. 

Chairman BAIRD. You too? 

Dr. KEITH. Oh, yeah. 

Chairman BAIRD. We must be on the same mailing list. 

Dr. KEITH. So I think that it is—the only cure for that is transparency. 

Chairman BAIRD. Mr. Inglis. 

POLITICAL, SCIENTIFIC, AND ECONOMIC CHALLENGES

Mr. INGLIS. Thank you, Mr. Chairman. 

It strikes me what we are talking about here is something that 

is very difficult to do because there is no profit to be made in it, 

and if you think about it, the other way of cutting off the CO2 has 

a real profit motive in it, and the way that you can really get 

things done in a free-enterprise society like ours is to give people 

an opportunity to make money. They will move quickly if they can 
186

make a buck. What you are talking about here, I think just involves government expenditures because I don’t know of any customer who would buy these things. So it means if you are doing 

appropriations to support this with, A, some real questions about 

the science of it, and B, selling people on the idea of using their 

tax money to spend money on something that they can’t see any 

tangible result from. It is a little bit like putting padding in a car 

to avoid injuries with DUI or something. I mean, maybe what you 

should do is stop the people from being DUI rather than putting 

padding in the car. And I am also aware that the Committee had 

an opportunity to be in Greenland and we heard about an earlier 

idea several decades ago of putting coal dust out on the glaciers in 

order to help heat up the glaciers. Gee, I am glad we didn’t do that. 

And we heard too, though, about the good thing of getting lead out 

of gasoline and the result is that real improvement in the situation 

in the glaciers. So it meant sort of a picture. I mean, one, we are 

thinking about putting out coal dust. In the other, we are just removing a noxious substance, and the result was really good. 

So you have to be real certain of the science and then you have 

to figure out how you sell a constituency on it, and the thing I am 

looking for always when dealing with climate change is some way 

of getting a two-fer or a three-fer, and this is a one-fer. I mean, you 

just get one thing, CO2 out of the air and you have a problem finding a constituency, you have real questions about the science. If 

you think about it, if you can incentivize people to really go after 

reducing emissions and make money at it, then you can create jobs, 

you can improve the national security of the United States, especially by breaking the addiction to Middle Eastern oil and you can 

clean up the air. It is a three-fer and it is driven by profit motive. 

Wow, what a deal. Because, you know, this thing, if we had done 

this by appropriations, we would be dragging behind our cars in a 

trailer, you know, with two technicians figuring out how to get an 

e-mail across but because this was profit motive, look at this incredible thing. They made a bazillion dollars making these things. 

So that is what we are after, right? And so I realize I am really 

panning the idea here, so does anybody want to defend it since I 

have totally panned it? Who wants to go? Dr. Rasch, you still look 

like you want to tell me. 

Dr. RASCH. Sure, I am happy to respond. I guess the first thing 

to say is that I think probably all of us agree with you on 99 percent of what you said. I think the first thing to say is that the only 

reason that we are considering doing geoengineering—it is going to 

cost money that we wish we didn’t have to spend—is because the 

consequences of not doing anything might be more costly. That is 

the first thing. Then the second thing to just mention is that of 

course we also want to find a way of changing our energy technology so that we are not emitting the CO2 or other greenhouse 

gases, and the best way is to do it the way that you are talking 

about. We are a bit concerned that it is going to take a while both 

to convert the technology to reduce or zero out emissions, and also 

even if we were to do that, it is going to take a while for the planet 

to come to some equilibrium with respect to the emissions that we 

have already made and those that are coming. There are also difficulties with respect to continuing emissions for things like trans-
187

portation sectors, which were also mentioned earlier this morning. 

So we don’t really like the idea of doing geoengineering, but we 

can’t see any way around it. We see that we may need to do 

geoengineering. 

Mr. INGLIS. I see that my time is up. I hope we may come back 

to it but, you know, it reminds me of the Malthusian predictions 

too about the manure in New York City. It really undercuts, I 

think, our efforts to do something about climate change to have 

Malthusian predictions. I mean, the reality is that Henry Ford created the car and made a bazillion dollars on it and the result was, 

we didn’t have horse manure piling up to second-story levels in 

New York City or however deep is was supposed to get. And so I 

really think that when those of that are out there trying to say let 

us take responsible action or sort of hear the chorus of a Malthusian prediction, then it really undercuts our effort of trying to get 

people to buy into this and say gee, we can make a buck, we can 

improve the national security of the United States, and if you care 

about it, you don’t have to care about it but if you care about it, 

we can clean up the air too. That is how to sell change. 

The other thing is, it is really hard to sell. I can tell you in the 

4th District of South Carolina, it would be extremely hard to sell. 

I yield back. 

Chairman BAIRD. Apparently Dr. Keith would like to speak about 

euphemistic Malthusian predictions, which may be a euphemism 

for horse pucky, but Dr. Keith? 

Dr. KEITH. I think profit motive and entrepreneurialism are just 

fantastic and I think it is vital that we actually talk about this in 

a positive way. We have solved an enormous number of pollution 

problems over the last 100 years. We made huge progress on cleaning up air and water and there was a lot of innovation that came 

about. I run a little company that is trying to innovate, and we 

don’t think we should make that money, in the long run, by government appropriations. We think what we need is a clean, transparent law where government doesn’t pick winners but does restrict the amount of CO2 going in the atmosphere, and we want to 

and intend to compete and win in that world. 

Chairman BAIRD. Mr. Rohrabacher. 

SKEPTICISM OF CLIMATE CHANGE

Mr. ROHRABACHER. Thank you very much, Mr. Chairman. You 

know, I come to this. I actually waded through the snow coming 

here, and noticing how miserable I would be without global warming would be even worse. Actually the snow we have had and the 

temperatures we have had in the last nine years totally are contrary to what we were told in this Committee for about 10 years, 

all the predictions of the people who came here to talk to us about 

global warming. I know they have changed it now to climate 

change because the climate doesn’t seem to be doing what they said 

it would do, but in this Committee, testimony after testimony about 

what was going to be happening. We were going to reach this turning point. It was going to get hotter and hotter until it would reach 

some point and then it would really get hotter, and it has been just 

the opposite. We come into this hearing today—just in the last 

month we have heard not only the revelations that came out of 
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these hacked communications which indicate a lack of scientific 

credibility behind certain issues that have been brought up in the 

global warming debate but we also have found that there was in 

the IPCC report itself that the Himalayan glaciers that were predicted, that prediction was not based on any scientific research. 

Just last week it was indicated that and found out that the guesstimate on the Amazon rain forestation, the elimination of the rain 

forest in the Amazon had no scientific research and basis, and we 

also heard just recently a statement from the Russian Academy of 

Sciences that the information they had provided the IPCC was 

cherry-picked before it was put into the computer model to have an 

outcome that was not a scientific outcome but an outcome that was 

predetermined by the people who were putting the project together. 

These things would cause us reason to doubt the premise which 

your request for the spending of billions of dollars to remediate a 

problem is based on. 

For the record, Mr. Chairman, I would like to place in the record, 

out of—there are thousands of such scientists, and you know them, 

who disagree with this theory that your proposals are based upon 

but I would like to put a list of at least 100 of those thousands of 

scientists who are prominent scientists who agree with the case for 

alarm regarding climate change is grossly exaggerated. Surface 

temperature changes over the past century have been episodic and 

modest. There has been no net global warming for over a decade. 

The computer models forecasting rapid temperature change abjectly fail to explain recent climate behavior. And finally, characterization of the scientific facts regarding climate change and the degree of certainty informing the scientific debate is simply incorrect. 

I would like to place for the record the list of 100 prominent scientists who agree with those statements. 

Chairman BAIRD. If it doesn’t exceed the requisite page limit—— Mr. ROHRABACHER. Well, we will squeeze them down into a little——

Chairman BAIRD. Because that is an issue. 

Mr. ROHRABACHER. —one page if you would like, Mr. Chairman. 

Chairman BAIRD. If you want to submit one page, then without 

objection. 

Mr. ROHRABACHER. Otherwise we would be wasting all of that 

carbon the paper. 

Chairman BAIRD. Well, it has happened before that we have 

sought to do that on our side with objections——

[The information follows:]
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Mr. ROHRABACHER. So now to the questions based on some of the 

reading that I obviously have had on this. What percentage of the 

atmosphere is CO2? I have asked that question, by the way, of numerous people, and after hearing all of the various proposals about 

the importance of CO2, most novices think it is 10 percent or 20 

percent of the atmosphere. What percentage is it? 

Dr. JACKSON. Three hundred and ninety parts per million. 

Mr. ROHRABACHER. It is .0395 something. It is less that one 

tenth of 1 percent of the atmosphere. As a matter of fact, it is less 

than one half of one tenth percent of the atmosphere. Is that correct? 

Dr. KEITH. Yes, and maybe it is useful to think about where the 

knowledge that that could cause a problem came from. It came 

from the Air Force geophysics lab in the 1950s. So one thing that 

you lose in all the hype, and IPCC has overhyped, and all the hype 

on both sides is the stability of the core science. So the original 

modeling that showed that surprisingly—it is surprising that that 

small amount of CO2 could have a big effect on climate. That modeling was first done accurately by the U.S. Air Force and it 

wasn’t—— Mr. ROHRABACHER. The point is not accurate. There are many 

scientists who disagree that that small amount of CO2 has anything to do with the changes in the climate, especially—now, is it 

your contention that this tiny, miniscule amount, and of course, 

mankind’s investment into that is only 10 to 20 percent of that. 

Eighty percent of it comes from natural sources. That makes it 

even more miniscule. That that is a more important factor to the 

change in our climate than solar activity? The biggest source of 

power in our universe but this little tiny thing is more important 

than that? 

Dr. LACKNER. I would say yes, and I don’t come at it as a climate 

scientist. I would be happy to stand away from this. I am a harmless physicist when it comes to this. But Joseph Fourier understood 

this in 1812. And really nothing much has happened new since 

Svante Arrhehius in 1900, and yes, if you were to take the CO2 out, 

the United States would be very much colder than it is today. It 

is a simple greenhouse gas, and what we are talking about are fine 

details of what happens if you make small changes to that admittedly small number. Nevertheless, it is important. If you take it 

out, you also have no photosynthesis. Your ocean would be a hydroxide solution. So there are lots of things which make this important. Nobody argues about argon, which is comparable in content, 

because it is inert. It doesn’t do anything. 

Mr. ROHRABACHER. At that time in the early——

Dr. RASCH. Those 100 scientists that you mentioned would not 

disagree with anything that Dr. Lackner just said. 

Mr. ROHRABACHER. But let me try——

Dr. LACKNER. Let me try to——

Mr. ROHRABACHER. Let me ask you this specifically. Has there 

been a time when the CO2 in this planet’s history, when the CO2

level was much greater but that we had abundant plant life, oceans 

that flourished. 

Dr. KEITH. Absolutely. So 50 million years ago there was 1,000 

or 2,000 parts per million CO2 in the air, several times what it is 
194

now, and there were alligators in the high Arctic and there is nothing wrong with that whatsoever. The problem is about pace of 

change. It took 10 million years for CO2 levels to come down from 

where they were, and we are planning to put them back up to that 

level in one human lifetime. That is 100,000 times faster. There is 

nothing inherently wrong with a warmer climate, but that argument is fallacious because it neglects the issue of rate of change. 

When things came 100,000 times faster, you have a problem. 

Mr. ROHRABACHER. Well, except, of course, if the earth has several volcanoes that erupt, right, and that might do as much change 

as what we do in a full year or two. Isn’t that right? 

Dr. RASCH. If you get a big enough volcano, it can have a catastrophic effect on the atmosphere. 

Mr. ROHRABACHER. So volcanic activity really has something to 

do with this as well that may even override what human beings do. 

Dr. LACKNER. It certainly will override a year or two. The point 

which convinced me to work on it, because I had to go through the 

same sort of questions 10, 15 years ago when the climate science 

was far less certain, and whether it is worth spending time on 

these issues. What convinced me is we can have a long and learned 

debate what precisely is the right number to stop at, but once we 

reach that number, we have to stop emitting, because to a very 

good approximation, this is like pouring water in a cup. As long as 

I keep pouring, it goes up, and so we could have an argument 

whether 450 is the point to stop and there are some people who are 

of a different opinion than I am on that, but——

Mr. ROHRABACHER. A lot of scientists, for example, suggest that 

the baseline that you are using to claim that there is a temperature change going on starts in 1850, and we all know that 1850 

represented the bottom of a 500-year decline in temperatures, 

which is what they call I think the Little Ice Age or something, 

which the scientists that I am talking about point to that and say 

there has not been any change, even though we have this supposed 

increase in CO2. 

Dr. JACKSON. It discourages me a bit, I must confess, to still be 

debating things like whether greenhouse gases are increasing and 

whether the earth is warming. The earth’s temperature is warming. In 1998—the only reason that there is some discussion about 

the warming slowing is the 1998 weather was off the charts in 

terms of warmth. It was unprecedented in terms of warmth, and 

it was so high that the bouncing around since then, it may have 

slowed a little bit. My suspicion is that in five years it will be back 

to the same—— Mr. ROHRABACHER. So you are saying that this 1850 argument, 

that using that as the baseline really isn’t accurate because we 

have actually grown a lot more than what would have normally 

been throughout the 1,000-year, 2,000-year history of humans. 

Dr. JACKSON. I am just saying that it is not an 1850 discussion, 

it is a million years and longer discussion through different methods. I am just saying that the knowledge base is quite strong. I 

guess I would also like to add that when we think about changing 

the earth’s climate, I would like—as a climate and environmental 

scientist, I would also like to remind people that there are millions 

of other species that we share this planet with, and for 50 million 
195

years those species were free to migrate and move. That is no 

longer the case, so we have to think about human adaptation and 

human cost but also the ability of the other species that we share 

the planet with to move in the kind of lifetime that David Keith 

was talking about——

Mr. ROHRABACHER. Well, the CO2 argument—and I certainly 

agree that we have a footprint but it is not just a carbon footprint, 

and thank you very much. I see my time is up. Thank you for indulging me, Mr. Chairman. 

THE SCIENTIFIC BASIS OF CLIMATE CHANGE

Chairman BAIRD. I thank the gentlemen for their responses and 

want to commend you. Some of the arguments that Mr. Rohrabacher has made have been offered previously to panels of climate 

scientists without response, and I commend you for the response. 

I want to drill down a little bit on one of these issues, and Dana 

and I are very good friends and we disagree on the conclusion here, 

but there is a premise that seems to be that if something appears 

to be a small quantity, that it then assumes it cannot have a large 

effect. My understanding is, ricin in microscopic quantities can be 

dreadfully fatal. I take a little tiny pill each day called Lipitor, 

which relative to my body mass is pretty darn small, and it seems 

to extend my life. If I were to put a thin, thin, thin film of plastic 

over your mouth, you would die. If I hold it under the sun, it will 

warm you up a lot. A thin film of plastic which relative to thickness of atmosphere is far smaller than the parts per million we are 

talking about, and yet it could—you know, nobody would dispute 

you lay a piece of plastic on the ground, sun comes through it, 

things get hot. So this fundamental core argument that because 

CO2 is a small percentage of our total atmosphere it cannot have 

dramatic effects is—we can illustrate countless examples in nature 

where apparently tiny quantities have dramatic impact. So I think 

we would do well to reject that as a line of argument. 

But beyond that, my understanding of the recent temperature 

data from this year suggests this past year was a pretty warm year 

in spite of the fact—I think proponents of climate change make an 

egregious mistake when there is a tornado somewhere or a hot day 

somewhere and they say oh, look, it must be climate change. The 

opponents are guilty of the same problem. And my understanding 

is the pattern of temperature last year was actually pretty warm 

year. Is that your understanding? And my understanding also is 

that IPCC and NASA itself have looked at the solar radiation issue 

and largely refuted the notion that solar radiation increases. I 

mean, they modeled it elsewhere and they said solar radiation increases are not believed to be responsible for the apparent temperature increase. Is that your understanding? The record will 

show that these four distinguished gentlemen all say yes on that. 

I think there is a need to—you know, the temptation is to say 

well, there is one thing or a few things that point maybe in the opposite direction or questions of doubt, and there is no question in 

my mind that if doubt is distorted on either side of an argument, 

that—as a scientist and someone who has introduced legislation to 

promote ethical scientific conduct, that is a problem. But a few bad 
196

examples don’t seem to me to overwhelm the abundant evidence 

that I think you gentlemen are citing. 

CHEMICAL & GEOLOGICAL CARBON UPTAKE

So back to the issue at hand of geoengineering. Let us talk about 

solar radiation management a little bit. I want to talk about that 

and also about the carbon uptake. We will start with carbon uptake. The white pine tree that you gave us, give us some costs, both 

carbon costs, you know, and what does it cost to produce that in 

terms of carbon and cost to manufacture? You mentioned, I think, 

25 cents a gallon. 

Dr. LACKNER. Well, this is once we are in a mass manufacturing 

mode. We are still in a research phase so we have developed this 

material which is an anion exchange resin. If it is dry, it absorbs 

CO2 out of the air. If it is wet, it gives it back. So around that we 

built a cycle which allows us to collect the CO2, compress it, and 

we will pay energy for that, and so the main energy consumption 

is the compression. Figure that we roughly give 20 percent of the 

CO2 we collected back because some distant power plant is generating electricity in order to feed that system, so that is the order 

of magnitude of what you have to give back. The cost of the electricity is small and would be well within that 25 cents. 

Chairman BAIRD. So you are able to—once that thing draws the 

carbon out of the air, you are able to then draw the carbon off of 

that? 

Dr. LACKNER. Exactly. So this is like a sponge to soak it up and 

then I squeeze the sponge out and then I can do with the CO2

whatever is necessary. I can put it to mineral sequestration, I can 

use geological sequestration or you could just happen to want some 

CO2 for a fizzy drink. I can sell you that CO2 for that purpose. 

Clearly, I have no carbon impact if I do that. 

Chairman BAIRD. But if we burp, we screw up the cycle. 

Dr. LACKNER. Yeah, you would have kept the cycle going. But for 

a small company, again, that actually gives you the profit motive 

because in the beginning those are the markets and quite clearly 

in the beginning I am not down to $30 of ton of CO2. We estimate 

that the next round where we go to a one-ton-a-day unit, we are 

at about $200 a ton on the first try. 

Chairman BAIRD. How about the carbon costs of producing the 

material? 

Dr. LACKNER. The carbon cost of that is nearly negligible to the 

total, because in a matter of a week or two this machine will have 

collected its own weight in CO2 multiple times over. Roughly 

speaking, without doing a careful lifecycle analysis, you have collected a few times your own weight, in the CO2 emitted that you 

have produced. Furthermore, the material is a polymer so at the 

end of the day it becomes fuel to close the cycle. 

Chairman BAIRD. And my understanding is, we are getting—there was an article in Science a couple weeks ago about how 

we are making some new developments in terms of molecules that 

may be able to—and catalysts that may be able to more efficiently 

strip carbon out as well. Is that——

Dr. LACKNER. Yes. There are a variety of options. We believe 

what we did here, we discovered actually a brand new way of doing 
197

it and we will pursue this further and try to drive the costs down, 

and one of the things we can do is just make the material finer. 

Therefore, we use less of it, and therefore the cost is coming down. 

That is why I am optimistic that mass production—I don’t just 

have to appeal to the world’s learning curves for other things when 

you say things get cheaper if you make more, but I can point my 

finger to things here and here and here. I can make it much cheaper. 

ALTERNATIVES TO FOSSIL FUELS

Chairman BAIRD. And one last point on this and then I will recognize Mr. Inglis. My understanding is that a portion of the energy 

demand, it will be very possible to meet it through renewable energies, particularly in off-peak times. 

Dr. LACKNER. Certainly, and——

Chairman BAIRD. So we are not having to burn more coal, for example, to power our carbon cleansing mechanism. We can use renewables to do that? 

Dr. LACKNER. You could certainly do that, and we actually have 

developed ways where we can wait for the electricity demand when 

you don’t need it so that we can fit in that way. But overall, I 

would argue you can also get away from fossil fuels, and the dream 

of the hydrogen economy is to use renewable energy to make hydrogen as a fuel. If I can give you CO2 and hydrogen, you can make 

any fuel you like with technologies we have developed in the 1920s. 

So it seems to me this opens the door both ways to carbon sequestration if you want to go that route, and if renewable electricity or, 

for that matter, nuclear electricity, becomes cheap enough to make 

it worthwhile. You can get independent of oil by making your own 

synthetic fuels. 

Chairman BAIRD. Thank you. 

Mr. Inglis. 

THE SUCCESSES OF PROTERA LLC AND THE NEED FOR

INNOVATION

Mr. INGLIS. So Dr. Keith, thank you for that answer for Mr. 

Rohrabacher. I think it is a very helpful explanation because if it 

is a pace of 100,000 times faster, that really helps people to understand why it is that it is a problem, and that is the kind of thing 

that really builds our credibility as we try to address the issue, and 

I am with Chairman Baird, I thank you for answering the question 

because quite often those questions do go—or those assertions go 

unchallenged and so very cogent explanation there. It is 100,000 

times faster. I think we can all understand that, that is fast. 

So right now I have to sort of celebrate something happening in 

our district that is relevant to this. Protera, which is an electric 

bus company, is announcing that they are coming to Greenville, 

South Carolina, at Clemson University’s Center of Automotive Research, where they are going to begin building these buses. The bus 

has a number of advances. It is made out of balsa wood that is infused with resins that make it as strong as steel. It has got a fiberglass case on it that is very light. It is about a third shorter but 

carries as many people as an average bus, a city bus, because it 
198

doesn’t have big diesel engines in the back, and it runs on 3,000 

pounds of batteries, heavy batteries. It is a lot of batteries. They 

are quick charge and quick discharge, 6-minute charge, which 

means—the physicists here can explain to us that that means they 

discharge quickly too, right? But they figure that by going around 

from stop to stop, and stop and have an extended stop, maybe a 

minute and a half, they can actually recharge the battery enough 

to get to several more stops. And so around the city that uses such 

a bus, there won’t be any emissions from the diesel. The electric 

bus goes faster than a diesel because you can go lickety split. I 

drove one right up the hill here several months ago, and we beat 

a city bus off the line, and all you do is put the accelerator down 

and that thing moves. It doesn’t have the grinding of the diesel and 

it doesn’t have the smoke coming out the back. And it has regenerative braking too so when you let off the accelerator, the thing 

slows down as it is recapturing that energy. What an exciting 

thing. These people have decided that the economics work right 

now, and I wish I were there now to celebrate this with them but 

I did a recording yesterday to celebrate it, and what I pointed out 

is, if we get action on climate change, those economics will look 

even better, so the amazing thing is that they have something that 

works right now but imagine them in the catbird seat if we do actually insist on accountability and say incumbent fuels, consider all 

of your externalities, force a recognition of all the negative 

externalities and suddenly Protera is going to be—wow, everybody 

is going to be asking for one of those buses or many of those buses 

and we are going to have jobs in South Carolina. We are going to 

have an improved national security because we are going to be saying to the Middle East, we just don’t need you like we used to. And 

we will clean up the air. 

Now, of course, that assumes a clean way of producing electricity, 

but if you insist there on internalizing the externals associated 

with the cheap coal, then we will fix that one too. We will be building IGCC machines in Greenville, South Carolina, at General Electric, creating a lot of jobs there. We will be creating windmills. 

They are building wind turbines at General Electric in Greenville. 

And so we will be building nuclear power plants with a whole high 

concentration of engineers in the upstate of South Carolina. 

Now, you see I have a parochial interest in this. I want to make 

a lot of people very wealthy out of figuring out a way to fix this 

problem, and we can create jobs in the process. We are going to say 

to the Middle East, we just don’t need you as much, and we are 

going to clean up the air. So what an exciting thing. So I just had 

to celebrate this Protera announcement, Mr. Chairman. Can I hear 

a cheer for Protera? 

Chairman BAIRD. Go, Protera. All I care about is you driving 

buses. 

Mr. INGLIS. Yes, I shouldn’t have admitted that. I don’t have a 

CDL. 

Dr. JACKSON. May I comment briefly? I think that is a wonderful 

example, and one way or another, one of the things that we clearly 

need is some sort of carbon price, and the reason I think for having 

a carbon price down the road is that you don’t pick winners and 

losers in terms of technology. You let the private sector and mar-
199

kets drive the innovation and the energy savings and all the technologies including perhaps things like capturing CO2 from the air 

but we must have a carbon price and we must figure out a way to 

do it smartly and efficiently to protect our jobs and business but 

that is what we need to drive exactly the kind of innovation that 

you are talking about. That is fantastic. 

Mr. INGLIS. And can I pass one on to you? How about this? Art 

Laffer, one of Reagan’s economic advisors, is a neighbor of Al 

Gore’s in Tennessee. They agree on a 15-page bill that I have introduced. It reduces payroll taxes and an equal amount shifts those 

taxes to emissions. So it is a revenue-neutral bill. It is also border 

adjustable tax so it is removed on exports, and it is imposed on imports. 

Dr. KEITH. That is beautiful. May I comment on the need for innovation? 

Mr. INGLIS. Yes. 

Dr. KEITH. I think private money can do great, and both Klaus 

and I are, in a friendly way, competing, and we both have private 

money to work on air capture. And in the long run prices are absolutely necessary to allow clean competition but we also have to find 

ways, and government has a role. It is not easy to figure out exactly how to do it right in incentivizing innovation because we just 

are not putting enough energy into energy innovation. The U.S. 

electric power industry puts as much money into R&D as a fraction 

of gross sales as the pet food industry does. I didn’t make that 

number up. We checked that number. It is a very small amount, 

and we need to find a way to make this economy more innovative, 

and private money is necessary but we need ways for government 

to encourage innovation both through specifics of tax policies and 

direct funding for basic R&D. I think that is crucial. 

Mr. INGLIS. You know, I found that out actually visiting the utility that is subject to a Public Service Commission. They are sort 

of proud of the fact they didn’t have an R&D department, and the 

reason is that they can’t figure out how to pass those costs along 

through the PSC, and so they took it as a point of pride that they 

weren’t charging the consumer with those. So it is a real chicken 

and egg kind of thing. You have to figure out how to—but if you 

establish a clear price and you insist on accountability, which I believe, by the way, is a very conservative concept. I mean, I am a 

conservative Republican and I am here to tell you that if you allow 

people to be not accountable for what they do, well, then you get 

market distortions. But if you insist on accountability, then those 

incumbent technologies lose to new technologies. 

Dr. LACKNER. Let me 100 percent agree with you on that point. 

We do need some way of holding people accountable for the carbon. 

My view is, this has to be somehow built into the price, ideally, as 

high upstream as you possibly can. And then we move on and say 

all these various options can compete. Your electricity-driven bus 

I think is a great idea. I am 100 percent behind that. It is a little 

harder for my sports car to have all of those batteries in it, and 

so maybe the 100 times higher concentration in the liquid fuel, 

which could be synthetic, is another option, but let the market figure that out, and what I am driving towards is that we shouldn’t 

close options off. Air capture is an option. Electricity is another op-
200

tion. Which of the two will win? I tell my students, I can’t tell you 

today. The markets will have to figure this out and it is too close 

to call with 50 years ahead trying to work this out, but we do need 

the market to sort this out. 

INCREASING STRUCTURAL ALBEDO

Chairman BAIRD. Thanks, Mr. Inglis. 

I want to ask two more quick questions and then, Mr. Inglis, we 

may finish at that point. It seems to me that the most basic form 

of—you folks have been very informative here and it makes sense 

to me that we ought to look at this much more than we are. The 

most basic form of geoengineering that I have heard about is paint 

your roof white, which actually is very little cost and dramatic benefit. Is that your understanding, that if we could move, you know, 

towards lighter colored shingles—in fact, I understand people are 

making photovoltaic shingles now. What are your thoughts on 

that? 

Dr. KEITH. Huge local benefits, such huge potential benefits——

Chairman BAIRD. In this city——

Dr. KEITH. —cooling loads and city-level loads, but I think it is 

pretty clear that as a method of changing he global climate, it is 

both too small of a matter and actually not cheap. But locally to 

help cities and to help reduce cooling loads, it can be very effective. 

Chairman BAIRD. And dramatic—not dramatic but noticeable impact on cooling loads especially. 

Dr. RASCH. If I could respond, it doesn’t have much effect on the 

brightness of the planet but it does have a big effect on the energy. 

Chairman BAIRD. So we are not going to change planetary albedo 

by painting our roofs white, but the city of Washington, D.C., could 

substantially reduce its load, and that means less air conditioning, 

that means less carbon burning for the air conditioning. 

Dr. RASCH. Yes, absolutely. 

ALTERNATIVE FUELS AND CONSERVATION PRIORITIES

Chairman BAIRD. In terms of research dollars, one of my concerns—I was just at the World Economic Forum and there is a lot 

of discussion about CCS, carbon capture and sequestration. We are 

building an enormous base infrastructure right now. We already 

have one in coal but we are building—China, particularly, and 

other nations, are continuing to expand on the bet basically that 

we are going to have some sort of CCS that is economically viable. 

And the projections we have heard in this committee previously 

suggest there is a real question about that, and on top of that, if 

you are adding more carbon, the efficacy of reducing the existing 

carbon that you are just trying to keep up with an ever-fleeing target. It would seem to me that we would be much better to do a couple of things, to make a large investment right away in conservation because that is your quickest and most immediate return on 

investment. Then put money into disruptive technologies like distributed photovoltaics or wind or like Dr. Daniel Nocera is doing 

at the Massachusetts Institute of Technology [MIT], some form of 

better hydrogen and fuel cell rather than letting the money go into 

these big coal plants that just commit us to a coal path and then 
201

make all your clever devices, Dr. Lackner, not reducing down to 

350, which we are already above 350 parts per million but trying 

to keep up with this fleeing target. What are your thoughts on 

this? If we throw so much money into new coal capacity 

versus—what does that do to us? 

Dr. LACKNER. I think we should do what you just said because 

it is important to go after the low-hanging fruit, but I come back 

to where I started, particularly if you talk about what other countries are getting into, you are talking in the end about a world of 

10 billion people who strive to have a style of living we take for 

granted, and I think we should do everything we can to allow that 

to happen. Now you need an awful lot of energy, probably four or 

five times as much energy as we are using today. So I started to 

ask myself the question, where could all that energy possibly come 

from? There are very few resources which are big enough to do 

that. I would argue one of them is solar energy. There is no question we have enough sunshine and we should have a big, big program there. 

Secondly, I think nuclear energy with all its problems is a second 

one which is actually large enough to solve this problem and can 

play as a truly big player. Thirdly, you have fossil fuels. We may 

be running out of oil. We are not so likely running out of gas and 

we are certainly not running out of coal in the foreseeable future. 

So in my view, we have some 200 years there to keep banking on 

that fuel, provided you have carbon capture and storage in place. 

So that has to be part of the bundle because otherwise you simply 

couldn’t dare to use all of this carbon. So in my view, standing back 

a little, there are three major resources and we better place three 

big bets, making sure that at least one of them pays out. And I am 

optimistic that each one of the three has a fair chance of getting 

through, but if we were to fail on all three, we would have an energy crisis of unprecedented proportion no matter how well we do 

in terms of conservation or improved efficiency. Those can help but 

they cannot solve the problem, and I would argue the other energy 

sources we are talking about on that scale are too small. So those 

three I would view as in a special category, and we have to pay 

attention that they work. And then the market has to figure out 

whether it is 30, 35, 40 or whether it is one winner takes all in 

50 years. I cannot predict that. But we better not close the door 

on any one of those. 

Dr. JACKSON. May I add wind to that list as well? I agree with 

all of that. I can’t pass up an opportunity to say thank you for emphasizing the need for conservation and renewables. Those are 

things that we can do now. When we are discussing 

geoengineering, we are talking about things that work at best 10, 

20 years and perhaps and hopefully never if we don’t get to that 

point, but it is increasingly likely that we will get to it because of 

the increasing use of fossil fuels. So anything that we can do now, 

and there are many things we can do now to improve efficiency and 

provide incentives for renewables like wind and solar, I wholeheartedly support, and the market is the best way to do that. On 

top of that, though, when we build a coal plant, that coal plant is 

on the ground for 40 or 50 years perhaps, so I do believe, as strongly as I feel about conservation and renewables, that we have to 
202

pursue at least economic and feasibility analyses of CCS. Perhaps 

carbon capture and storage directly from the atmosphere is another 

example. These are not—it is not an either/or situation. In my 

view, these are backup plans because we are not doing the job we 

should be doing as quickly as we should be doing it. 

COAL AND CARBON CAPTURE AND SEQUESTRATION

Dr. KEITH. CCS has become a bit of an orphan child, so I think 

we should do everything we can to stop building any new coal 

plants without CCS. I would be happy to see a ban. But I think 

it is tempting to say, and I agree very much with the idea that 

solar and nuclear and coal with capture are the big players in the 

long run, wind to a lesser extent. But I think it is important to be 

clear about the politics of CCS right now. It is an orphan child. The 

NGOs at best are lukewarm and the coal companies’ preferred 

strategy, in many ways, would be to have it be R&D forever so they 

don’t get regulated. And so it is sort of caught in between the two. 

Yet nevertheless, it looks to those of us who spent a lot of time on 

it that you could actually build gigawatt-scale power using coal 

with capture today, and the costs of doing that would be much 

lower than, say, the cost of solar today, much meaning factors of 

several. 

Chairman BAIRD. With respect, there is substantial dispute of 

that. 

Dr. KEITH. I actually don’t know any serious dispute. I have 

served on the IPCC panels. 

Chairman BAIRD. About the cost curve? 

Dr. KEITH. Here is a simple way to say it. The feed-in tariffs that 

we need to make solar happen are of order 30, 40 plus cents a kilowatt hour in places where we are really doing it. I helped to get 

in Alberta, where I come from, one of the first—probably what will 

be the first megaton-a-year scale plant happen. I helped to recommend and was involved in the contracting for that. Those costs 

are substantially lower. So they will be done in three years for a 

million-ton-a-year effort and that is baseload power. It is ugly. Nobody likes it. It is not sexy. It is something that sort of nobody 

wants but it is something you can actually do and provides low CO2

electricity at a cost that is reasonable, and I think we would be 

very foolish to throw it out. 

Chairman BAIRD. I will not stipulate to that, having heard Mr. 

Heller’s comments in Davos last week. 

Dr. JACKSON. I am not sure I agree completely with that either. 

Dr. LACKNER. It is indeed a complicated story, but if you look 

back to the sulfur discussions, the sulfur dioxide discussions in the 

1980s, the estimate right before it happened where typically an 

order of magnitude larger. I think in the absence of economic incentives, prices tend to escalate and so I would argue there is a 

complicated story. If you want my intuitive feeling, and it is no 

more than that, these costs will come down to somewhere around 

$30 a ton in power plants. 

Chairman BAIRD. I also wanted to say, to say that it is an orphan 

child, the energy bill that passed the House had $100 billion over 

time into CCS. That is a hell of an orphan. You were saying, Dr. 
203

Rasch, the best you could get was $1 billion. Was it even a billion? 

It was a million. 

Dr. RASCH. A billion dollars for climate, and we are currently at 

a million dollars per year for geoengineering. 

Chairman BAIRD. A million for geoengineering, so we are—order 

of magnitude. 

Dr. RASCH. Many orders of magnitude. 

Chairman BAIRD. Three orders of magnitude. 

Dr. LACKNER. Five. 

Chairman BAIRD. Five orders. Yes, right, five orders of magnitude. And so I don’t think it is an orphan child by any means, 

and I think as an orphan child, it is a darn expensive child when 

you are putting $100 billion in. So if you are going to say that yes, 

the cost of CCS may come down, well, what if you put $100 billion 

in alternative technologies? 

And one last note on this and I will get to Mr. Inglis. The coal 

cost is not just the carbon cost. Five thousand miners a year die 

in China. It is a centralized system with a very inefficient transmission. We lose a tremendous amount of power across the transmission. There are all the other eminent domain issues, whether 

it is pipelines to transport the carbon or transporting the energy 

through those lines. I am very much, personally, much more of a 

distributed energy person with backups of the kind of thing you are 

doing, but I worry greatly about the big investment in coal, and 

$100 billion is a lot of darn money that could go somewhere else. 

Mr. Inglis. 

Mr. INGLIS. Thank you, Mr. Chairman. 

ECONOMICALLY VIABLE ENERGY SOURCES

Just briefly. I don’t know, Dr. Rasch, whether—you referenced $1 billion for a year in climate research. Our numbers show it is $2.5 

billion. 

Dr. RASCH. I tried to cite the location for the information that I 

used to assess that, but I could be off by a factor of two. You can 

also correct me if I am not looking at the right numbers. I am glad 

to be educated on that. 

Mr. INGLIS. Which is a fair amount of money. The thing I just 

go back to is, what we see in this Committee quite often is some 

things that work and we know they work. For example, wave energy works. It has obviously got to work. I mean, you can do it all 

kinds of waves. The question is whether it works economically, and 

the way to get things—I believe a basic rule of government is to 

basic research. I mean, it is an important function we do. But then 

once it gets into the applied range, what you are looking for is just 

economics at work, and when those economics start working, things 

happen quickly. So the internet came from defense research that 

then saw real opportunities in the private sector, and wow, what 

an opportunity it was. 

By the way, I might point out this 15-page bill, do another commercial for it. It starts out at $15 a ton, gets to $100 a ton over 

30 years. But we can go steeper than that if you want to. Just give 

me a tax cut somewhere else. In other words, how low do you want 

to go on taxes? How low do you want to go on reducing those FICA 

taxes? I will go all the way down and then we will shift them on 
204

to something else. So the idea of the curve is, it gives a period of 

time for innovation and it starts going more steeply. But the process is—I just want to point out, the bill, as I said, that Art Laffer, 

Ronald Reagan’s economic advisor, and Al Gore both support this. 

It is 15 pages compared to the 1,200-page cap-and-trade monstrosity. And so—which is a tax increase, decimates American manufacturing and is a trading scheme that Wall Street brokers would 

blush about. And so we have to find something simpler and something that people can say oh, I see, we are just going to—you are 

going to give me money in my pocket so I can go buy these wonderful shingles that Chairman Baird was just talking. We are getting 

ready to need to replace shingles on our house in several years. I 

want to replace them with solar-collecting shingles. But I need 

some money in my pocket, so reduce my FICA taxes and I got some 

money now to innovate. If you just give me a tax, I am stuck, I 

don’t have money to innovate. And the cap-and-trade folks who go 

around saying oh, it is not going to increase energy cost, well, then 

why do it? I mean, it is disingenuous. Of course it is going to increase energy cost. Otherwise you wouldn’t be doing it. 

But in my case, what I am saying is, I have money for you in 

your pocket. Then we are going to increase energy cost but I admit 

that energy costs will go up under what Art Laffer, Al Gore and 

I are talking about. But we have got a tax cut. If Art Laffer is on 

the scene, you can be assured that it starts with a tax cut. And so 

you have money in your pocket. It is just a small fair tax. It is one 

sector fair tax. 

Anyway, enough of my commercial, Mr. Chairman. Thank you. 

Chairman BAIRD. I am actually a supporter of the commercial 

product. 

CLOSING

I want to thank our witnesses. We could go on for a great length 

here but you have been very generous with your time and your expertise, and it has been most informative to us. As is customary, 

the record will remain open for two weeks for additional statements for the Members and for answers to any follow-up questions 

the Committee may ask of the witnesses. And with that, the witnesses are excused with our great gratitude and appreciation for 

your work. 

[Whereupon, at 12:25 p.m., the Subcommittee was adjourned.] 
(205)

Appendix 1: 

ANSWERS TO POST-HEARING QUESTIONS
206

ANSWERS TO POST-HEARING QUESTIONS

Responses by David Keith, Canada Research Chair in Energy and the Environment, 

Director, ISEEE Energy and Environmental Systems Group, University of Calgary

Questions submitted by Chairman Brian Baird

Q1. Why does the rate of change of carbon dioxide concentration suggest climate 

risk?

A1. Several independent lines of evidence suggest that carbon dioxide concentrations reached about 1000 parts per million (ppm) during the beginning of the Eocene 

about 55 million years ago, these carbon dioxide levels then declined to about one 

third of that value over a few tens of millions of years. The Eocene climate was far 

warmer than today’s. Crocodilians walked the shores of Axel Heiberg Island in the 

present-day Canadian Arctic. While there is lots of scientific uncertainty about the 

precise amount of climate change that will arise from increasing carbon dioxide levels, there is no doubt that carbon dioxide levels are currently being driven by combustion of fossil fuels and that were we to continue increasing our combustion of 

fuels at the current rate we would drive concentrations to roughly 1000 ppm by the 

end of the century. 

This increase in atmospheric carbon dioxide over a century would be, therefore, 

roughly as large as the declining carbon dioxide over the few tens of millions of 

years that followed the Eocene thermal maximum, that is a human driven rate of 

change perhaps 100,000 times larger than the average rate in nature. 

There is nothing wrong with the Eocene climate; there is no inherent reason we 

should prefer our crocodiles in the Florida Keys rather than on Axel Heiberg Island. 

The climate risks come from the rate of change, not because the current climate is 

some magic optimum for life. Our infrastructures, our crops, the very locations of 

our coastal cities have evolved for the current climate. The slow adaptation that has 

anchored us to the current climate puts us at risk if climate changes fast. The climate has varied for billions of years, and would keep changing without us, but on 

our current high-emissions path, the rate of climate change over the next century 

will likely be many times faster than humanity has experienced in the past millennia. 

While it is beyond the ability of science to predict the exact consequences of this 

increase in carbon dioxide, both our understanding of the physics of carbon dioxide 

and climate developed over the last century and with our understanding of the geological record suggest that the resulting climate changes will be dramatic. While the 

consequences of climate change may be somewhat worse or somewhat less severe 

than our models that predict, there is simply no scientific line of argument that concludes that we should expect no climate response to this increase in carbon dioxide.

Q2. Is it possible to somewhat confine the impacts of atmospheric geoengineering 

strategies?

A2. The climate throughout the whole world is coupled together by winds and ocean 

currents that move heat and moisture between distant locations. This means that 

the whole world’s climate is strongly coupled together as an interacting system. This 

strong coupling is not a one-to-one link. Its possible for one area of the world to cool, 

or to be cooled by some external influence such as geoengineering, while other parts 

warm. Nevertheless, in general and on average, any manipulation of solar radiation 

that substantially alters the climate over a large area, such as that of India or the 

continental United States, will necessarily involve the alteration of climate over 

much larger areas. Future research might find some particular locations or methods 

that reduced this coupling, but I suspect that the physics of the atmosphere makes 

it practically impossible to control climate of different parts the world in a completely independent fashion. 

So, to answer the specific question, geoengineering that focused on cooling the 

Arctic and thus increasing the extent of Arctic sea ice, could not be completely localized, and would necessarily have influences that would be felt over much of the 

northern hemisphere. 

That said, it’s completely possible that geoengineering could be used both help 

cool the Arctic and help reduce the severity of climate change over the areas covered 

by the South Asian monsoon. It is not correct to assert that these two objectives 

are necessarily in opposition.

Q3. Will adding sulfur in the stratosphere increased acidification the ocean?
207

A3. Sulfur added to the stratosphere will be returned to the earth as sulfuric acid 

in rain. However the amounts of sulfur now being contemplated are sufficiently low 

that there are no serious concerns about acidification of surface waters. 

Combustion of fossil fuels, most importantly coal, currently adds about 50 million 

tons of sulfur to the atmosphere each year. The resulting air pollution impairs the 

health and shortens the life of millions around the world, and also increases the 

acidity of surface waters, a phenomenon called ‘‘acid rain’’. The worst environmental 

effects come from concentrated sources that overwhelm the buffering capacity of 

local lakes causing them to become acidified. Because of the way the oceans are 

chemically buffered, this addition of sulfur is not a substantial contributor to ocean 

acidification which is primarily caused by carbon dioxide. 

Most discussion of sulfate geoengineering proposes adding a few million tons a 

year of sulfur to the stratosphere. At first glance, one might assume that the impact 

of this geoengineering on acidification of surface waters would thus be about a tenth 

as bad as the current impact of sulfur from fossil fuel combustion. However because 

the sulfur injection in the stratosphere would be deposited much more evenly 

around the world the rate of acid deposition would be far lower (e.g., 100 times 

lower) than the concentrated acidic deposition that causes acidification of lakes by 

overwhelming their natural buffering capacity. The overall impact of these sulfur 

emissions on acidity of surface waters are therefore thought to be vanishingly small. 

While it seems unlikely that addition of sulfur in the stratosphere will be a significant contributor to acidification of surface waters, it’s important to remember 

that there a host of other potential environmental problems that might arise from 

the injection of sulfur into the stratosphere, and that these can only be evaluated 

by a research program which enables scientists to quantify these risks.

Q4. How much funding for geoengineering is appropriate?

A4. I think it’s important to start with a relatively small amount of funding for 

Solar Radiation Management, and then to gradually increase the funding as the 

community of active scientists and engineers grows. I would suggest starting with 

about $5 million per year and then ramping the funding up towards $25 million per 

year over about five years. 

I suggest starting small because research programs (however important) can fail 

if too much money is spent too quickly. This seems to me a particular concern here 

because the topic is (justifiably) controversial and there is a relatively small community of serious scientists who seem currently inclined to work on the topic. Under 

these circumstances a sudden ‘‘crash’’ research program with a lot of funding would 

inevitably find some research which was ill considered and controversial raising a 

chance at the entire program would be killed. It’s important to learn to walk before 

one runs. 

The agencies best positioned to begin funding research are likely the NSF and 

DOE’s office of science, but many other agencies including, for example, NOAA, 

NASA and EPA clearly have capabilities that will be important as a research program grows. 

I don’t believe, however, that agency funding alone will be sufficient for the program to thrive. There is a vital need for a crosscutting role which articulates the 

broad objectives of the research program, minimizes duplication, and provides a 

forum for within which interested parties, including nongovernmental civil society 

groups such as representatives of major environmental and industry organizations 

can advise on the programs scope and progress. I suspect that the Office of Science 

and Technology Policy will be best positioned fill this role. I suspect that the presence of broadly representative advisory panel would serve as a place for parties to 

air their differing views about the merits of this research area and that that would 

in turn increase the chance of establishing a stable and sustainable research program that serves the public interest. 

Finally I want to emphasize the need to begin research program quickly. Research 

programs are starting in Europe and in private hands as are international efforts 

to ban all such research through existing treaties. The absence of a U.S. federal research program means that the U.S. government is unable to play an effective role 

in shaping the direction of research on solar radiation management in the public 

interest.

Q4. How to coordinate SRM and CDR?

A4. As I said in my opening testimony: SRM and CDR each provide a means to 

manage climate risks; but they are wholly distinct with respect to (a) the science 

and technology required to develop, test and deploy them; (b) their costs and environmental risks; and, (c) the challenges they pose for public policy and regulation. 
208

Because these technologies have little in common, I suggest that we will have a 

better chance to craft sensible policy if we treat them separately. 

As research programs, I don’t believe they require more coordination with each 

other than either of them do with other areas of climate related research such as 

research into low carbon energy systems or adaptation to climate change. All of 

these (and others) need to be woven into a coherent national strategy for managing 

climate risk. But I see no special reason for tight coordination between SRM and 

CDR research. I don’t believe one should attempt to avoid use of the word 

geoengineering, as attempts to avoid controversy by avoiding use of controversial 

terms are rarely, if ever, well advised; but in crafting a research program should 

one should treat SRM and CDR independently and used the word geoengineering

primarily in association with SRM.
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ANSWERS TO POST-HEARING QUESTIONS

Dr. Philip Rasch, Chief Scientist for Climate Science, Laboratory Fellow, Atmospheric Sciences & Global Change Division, Pacific Northwest National Laboratory

Questions submitted by Chairman Brian Baird

Q1. In your testimony you suggested employed field and modeling studies to examine 

the aerosol indirect effect, which is critical to understanding the marine cloud 

whitening strategy, and climate change more generally. Please describe what is 

lacking in our understanding as it applies to geoengineering?

A1. As a reminder, the term ‘‘aerosol indirect effect’’ refers to the response of clouds 

to the presence of aerosols. Aerosols affect clouds in many ways. They can act to 

‘‘whiten’’ clouds or make them more extensive, or more persistent, all of which will 

make the clouds more reflective to sunlight, and thus cool the planet. But aerosols 

can also act to trigger precipitation, depleting the cloud of condensed water, reducing cloud amount, and reducing the cloud lifetime, making the clouds ‘‘less white’’. 

These processes can act simultaneously, with some effects essentially counteracting 

others. This makes the effect of aerosols on clouds very uncertain (this is thoroughly 

discussed in the Assessment of the Intergovernmental Panel on Climate Change report). Science currently believes that on balance that aerosols tend to make clouds 

whiter, and that increasing aerosols will tend to cool the planet. 

Key points regarding this feature of the climate system as it applies to 

geoengineering include:

1. The ‘‘cloud whitening’’ geoengineering strategy depends upon the ‘‘more 

aerosols➔ more/brighter clouds➔ cooler planet’’ effect to work. We need to 

be sure that this aspect of the aerosol indirect effect is the dominant 

one for this geoengineering strategy to work.

2. Equally important, the aerosol indirect effect is critical to our understanding 

of climate change in the past, and in the future. Scientists believe that 

aerosols have increased dramatically over the last 150 years. If our understanding is correct, then the aerosols will have tended to cool the planet, partially compensating for the warming arising from increasing 

greenhouse gas concentrations. We believe that in the future the warming from more and more greenhouse gases will eventually ‘‘win out’’ over the 

cooling from aerosols, especially if we continue to clean up our emissions of 

aerosols. But in the past we think both effects played a role. Our lack of 

precision in knowing how much aerosols acted to cool the planet in 

the past also interferes with our ability to identify how much the 

greenhouse gases warmed the planet in the past and will warm the 

planet in the future.

The same research on the aerosol indirect effect that will help us evaluate the 

positive and negative consequences of geoengineering will help us understand how 

much aerosols have been compensating for the warming arising from greenhouse 

gases. Our lack of understanding confounds our ability to interpret the past temperature record, and to predict the changes that will occur in the future. 

What kinds of studies would be most useful for exploring the aerosol indirect effect? 

One very good way of understanding the aerosol indirect effect is to try to deliberately change a cloud system for a short time period. One would try to measure 

the cloud properties in an ‘‘unperturbed environment’’ and then do the same kind 

of measurement for the same type of clouds after deliberately and carefully trying 

to change the clouds to see whether our models can predict the changes that we 

see in the cloud system. The desired perturbation would be introduced for a relatively short period of time, over a small area. Mankind changes clouds all the time 

through pollution, but we don’t do it in a way that makes it easy to measure, or to 

identify the response of the clouds. 

The best way to do this is in the context of a scientific field experiment. The field 

experiment should be designed to deliberately change the local cloud system for a 

short time. It would introduce a local change far smaller than the kinds of changes 

to aerosol amounts introduced by, for example, emissions from a large city, or a 

large forest fire, and thus the field experiment would be expected to have much less 

effect on climate than those already produced by many other situations. 
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Our models suggest that the cloud systems most susceptible to the ‘‘cloud whitening effect’’ are those called ‘‘marine stratocumulus’’. These cloud systems are also 

very important climatically, so it would be an obvious cloud system to study first. 

Marine Stratocumulus clouds were recently studied in the VOCALS field experiment. The difference between VOCALS and a study designed to understand the aerosol indirect effect would be that the study would attempt to deliberately change 

the cloud system for a short time.

Q2. In your testimony you explain that lab and fieldwork are critical to assure that 

the physical processes that are critical to climate are understood. What scale 

would ultimately be needed to field test these SRM technologies to develop the 

technology and to test its effects?

A2. I advocate conducting scientific research to understand approaches to and implications of geoengineering, particularly as they relate to a deeper understanding 

of the dynamic processes and interactions of aerosols and cloud systems. Lab and 

Field tests are required at a variety of scales to explore the relevant issues. I describe a sequence of studies in the next few paragraphs.

1. At the smallest time and space scales it is important to see whether we can 

produce the sea salt particles that are suggested to be used to seed the 

clouds. The first steps would involve production of the particles on a laboratory bench scale for a few seconds.

2. If engineers were able to produce the particles for a few seconds then the 

next stage would be to study how those particles interact with each other 

and their environment after they are produced. Do the particles bump into 

each other and stick to each other growing big enough to sediment out from 

gravity? Do they mix rapidly with surrounding air or stay confined near the 

surface like the particles from a fog machine? Some of these tests could be 

done in a big warehouse, others off the end of a pier for a few minutes, to 

a few hours.

3. If the previous tests are positive then larger scale field tests become informative that require studies of over areas of the ocean the size of a few tens 

of city blocks for a few hours to answer questions like the following. How 

rapidly would the salt particles mix into the surrounding air? How long 

would they last? Does it matter whether they are produced during the day 

or at night? Do they go into the clouds as our models suggest? Does it matter 

what kind of a cloud environment the particles are near? (our models suggest 

that it would matter). How many particles survive after they are produced. 

How rapidly do they mix with their surroundings? All of these studies would 

take place for such a small area and over such a small amount of time that 

they would be indiscernible a few kilometers away, or a few hours after they 

were stopped.

4. The next set of field tests would reach the scale where the sea salt particles 

might actually influence cloud system for a short period of time. Stage 1 (involving a single small research aircraft nearby a single emitter of salt particles) would be to see whether scientists could produce a ‘‘ship track’’ like 

the ones that are seen regularly in satellite pictures as a result of ship pollution, and to try to construct experiments where the effects of the sea salt 

particle emissions could produce a measurable effect on the cloud. Stage 2 

studies on a larger scale (maybe a box a hundred kilometers on a side, involving 2–3 aircraft and a ship to make measurements above multiple 

sources of sea salt particles) would look at: a) how many particles are needed 

to brighten a particular kind of cloud; b) the influence of the seeding on surrounding clouds; c) how many sources that emit particles are required to influence a particular type of cloud over a small region (say a square a few 

tens of kilometers on a side). One would then be in a position to use that 

kind of a perturbation to answer the question of whether our models are able 

to predict the evolution of a cloud and its response to a perturbation. Various 

strategies could be employed by turning the sea salt particle source on and 

off for a few hours, or by seeding patches of clouds adjacent to unseeded regions, and contrasting the behavior of the cloud in both regions to explore 

how the salt particles influence that particular cloud type. This kind of field 

experiment should be performed at a variety of locations to see whether scientists are able to predict the response of models to such a perturbation for 

different situations.

Larger scale studies: All of the previous field tests would be designed to introduce a local change that is far smaller than the kinds of changes to aerosol amounts 
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introduced by, for example, emissions from a large city, or a large forest fire, and 

the emissions would take place for only a brief time. Because the sea salt particles, 

and the clouds themselves persist for only a few hours to a few days the field experiment effects would disappear rapidly, and one would not be able to detect the effects 

of the experiment itself a few days after sea salt emissions were terminated. 

If the previous studies indicated that it were possible to introduce measurable and 

predictable changes in clouds, then more intrusive studies on the climate system 

would need to be considered. The next level of field experiments could have possible 

(temporary) effects on the climate system, and such studies would require a much 

more intensive level of scrutiny, governance and planning. These type of field experiments would attempt to introduce significant changes in clouds for a sufficiently 

long time over a broad enough region that they would temporarily cool an small 

area of the ocean surface, and possibly introduce small shifts in winds or precipitation patterns. While the study is taking place, it could have an equivalent effect to 

that introduced by the pollution from a city on clouds. It would still have a much 

smaller impact on climate than many major features like ENSO, but it could be 

large enough to actually be detectable days or weeks after the field experiment had 

taken place. It will take a dedicated and coherent research program to understand 

how one would design such field experiments to maximize the possibility of detecting temporary changes in surface temperature, winds and precipitation. One wants 

to make changes that are large enough to be detectable, but small enough that they 

will disappear soon after the field experiment is over. It is difficult to outline a complete and appropriate strategy at this scale without more research. 

Field experiments at scales larger than this, for longer time periods would have 

more and more impact on the climate, and thus require more and more caution.

Q3. Is it possible to somewhat confine the impacts of atmospheric-based 

geoengineering strategies, marine cloud whitening or stratospheric injections, to 

protect geographically-specific areas?

A3. The Earth system is interconnected in many ways, and all geoengineering strategies will probably affect all parts of the planet, but the effects will be felt most 

strongly near the area where the sunlight shading is strongest. The marine cloud 

whitening strategy should have a much more ‘‘localized influence’’ than the stratospheric aerosol strategy because the aerosols near the surface and the clouds they 

affect have a much shorter lifetime than the stratospheric aerosols. Climate models 

suggest that the cloud whitening strategy will maximize the cooling in local regions, 

although the effects will gradually spread away from a local area as the planet adjusts to the local cooling and that cooling effect is transmitted to other areas by the 

winds and ocean currents. This aspect of geoengineering research requires more 

study.

For example could SRM be localized specifically for the protection of polar 

ice? 

It may in principle be possible to apply either the cloud whitening strategy, or 

the stratospheric aerosol strategy to protect polar ice. Computer model studies by 

Caldeira and colleagues suggest that if it were possible to shade the Arctic by reducing sunlight reaching the Arctic surface by 10–20% then polar ice could be preserved 

to the current ice extent and thickness, but Robock and colleagues have shown that 

stratospheric aerosols introduced over the Arctic will spread to lower latitudes and 

influences features there also. It may also be possible to use the cloud whitening 

strategy to maintain sea ice extent and thickness, because there are many low 

clouds in the Arctic during the summertime. There are a number of relevant studies 

that could be made to explore these issues:

1. It would be useful to understand how stratospheric aerosols introduced in 

the polar regions evolve. This would include knowing how rapidly the 

aerosols propagate to lower latitudes, and how rapidly they are removed 

from the stratosphere by sedimentation and mixing. Both computer models 

and field experiments should be used in these kinds of studies.

2. It would be useful to explore how susceptible low-level polar clouds are to 

whitening by using aerosol particles. Most of the focus to date has been on 

whitening clouds at subtropical latitudes and little or no studies have been 

done in polar regions. Literature reviews, computer models studies, and 

fieldwork would help in identifying the efficacy of whitening polar clouds.

3. It is worthwhile noting that very little work has yet to be done in studying 

the influence of geoengineering on ocean features (boundary currents, deep 

water formation and features like ENSO) or ecosystems. The changes to 

these features will occur only if geoengineering techniques are applied for 
212

months or years, so they may not be critical for the very earliest studies but 

these features are very important to the planet, and work should be done to 

understand the impact of geoengineering on them.

If it is unclear whether or not localized geoengineering is possible, what 

types of research could help inform the answer? 

More work can be done in each of the areas mentioned above with computer modeling. As technology becomes available to produce the particles needed to explore a 

given geoengineering strategy it would make sense to develop small scale field programs to verify the behavior predicted by the computer models. As discussed above, 

the initial field studies would not be designed to understand the consequences of 

geoengineering to the planet, but only to explore our understanding of the effect on 

components of the climate system at the process level by answering such questions 

as: 1) how rapidly do stratospheric aerosol particles grow? 2) how quickly are they 

flushed out of the stratosphere? 3) can we produce stratospheric aerosols in sufficient numbers that they might shield the planet? 4) how do sea salt particles mix 

near the ocean surface in polar regions? 5) Is there special chemistry taking place 

on those sea salt particles that influences for example ozone concentrations in the 

Arctic? 6) do the sea salt particles act to effectively whiten Arctic clouds in summer? 

These are just examples of the questions that need to be considered.

Q4. In your testimony, you stated that geoengineering research receives about $1M 

per year in funding, and roughly $200,000 of that is from federal sources. What 

initial funding levels would you recommend for a federal program authorizing 

atmospheric sulfate injection and marine cloud whitening research?

A4. I think a minimal funding level of $5–10M/year from federal sources for scientific research would help progress in geoengineering research, and also provide reassurance to society that the research is being done in an objective and unbiased 

manner. This level would allow some exploratory work to take place with strategies 

that have already been thought of. The work could involve computer modeling studies, and some support for lab and bench studies to explore the technology needed 

to produce aerosol particles for either the stratospheric aerosol, or the cloud whitening to be done. That funding level might also allow some support for as yet unidentified strategies to be fleshed out. 

As our understanding of a particular approach increases more money would be 

required. A single ambitious field study for cloud whitening would involving multiple aircraft, a ship for a month, support for satellite studies and scientific research 

would require $20–30M to see whether one could actually produce a measurable effect on the reflectivity of the planet locally. More money would be needed for planning the field experiment and analyzing the results. 

It would probably take another factor of 10 in funding if one were to then start 

considering measuring the consequences to the planet (by for example looking for 

the impact on ecosystems, or on ocean features) for geoengineering that might actually have a measurable effect on the planet.

Which agencies and or national labs would be best equipped to initiate 

such modeling and laboratory and field-based research? 

NASA, DOE, NOAA, and NSF all have a mandate to study various relevant components of the earth system and climate change science. I believe firmly that each 

of these agencies can and should participate in research in stratospheric aerosol and 

cloud whitening strategies. Here is a quick list of some of the relevant labs by agency and their particular expertise. Each of these agencies also funds university and 

other research entities and they should also play a part.
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These Agencies also have a great deal of relevant expertise in CDR, but I did not 

testify on that topic and will not make recommendations on how research in that 

area should be conducted.

Q5. The science and technology committee has held three geoengineering hearings 

and each witness at each hearing has emphasized the deep distinctions between 

the two types of geoengineering: solar radiation management) SRM) and carbon 

dioxide removal (CDR). If legislation were developed to facilitate geoengineering 

research, how should these distinctions be dealt with or accommodated? For example should CDR research initiatives be sited amongst existing activities at 

federal agencies while SRM research is authorized separately under the umbrella of ‘‘geoengineering research?’’

A5. I agree that CDR and SRM techniques should be treated separately, both at 

the funding level, and in terms of their oversight, and research goals. I see no reason why CDR research could not be accommodated within the existing activities involving managements of CO2 and the Carbon Cycle. I do believe that SRM should 

be authorized separately.
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ANSWERS TO POST-HEARING QUESTIONS

Dr. Klaus Lackner, Department Chair, Earth and Environmental Engineering, 

Ewing Worzel Professor of Geophysics, Columbia University

Questions submitted by Chairman Brian Baird

Q1. The mineral sequestration technologies you describe are certainly distinct from 

the technologies being researched through existing CCS programs at the Department of Energy, such as the Clean Coal Power Initiative (CCPI). In your testimony, however, you described mineral sequestration as ‘‘Carbon Storage 2.0.’’

a. Should mineral sequestration research be sited among the existing CCS activities within the federal agencies?

b. Alternatively, should mineral sequestration research activities be undertaken 

in a newly established, separate research program?

c. Which federal agency(s) would be best suited to carry out mineral sequestration research activities?

A1. Mineral sequestration is a particular form of CCS, so it could well be sited 

among existing CCS programs. However, most funded CCS technologies are further 

down the development path. Mineral sequestration and other more innovative technologies would benefit from an institutional home that looks at a longer development horizon. A stronger role of basic sciences and the USGS would be very welcome.

Q2. The Science and Technology Committee has held three geoengineering hearings, 

and each witness at each hearing has emphasized the deep distinctions between 

the two types of geoengineering: solar radiation management (SRM) and carbon 

dioxide removal (CDR).

a. If legislation were developed to facilitate geoengineering research, how should 

these distinctions be dealt with or accommodated?

b. For example, should CDR research initiatives be sited among existing activities at federal agencies, while SRM research is authorized separately under 

the umbrella of ‘‘geoengineering research?’’

A2. Solar radiation management and most carbon dioxide removal have very little 

in common. Specifically, the technical capture of carbon dioxide from the air is certainly a form of CCS and naturally fits under this umbrella. It is very different from 

technologies that aim to modify natural geodynamic systems.
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1 Bala, Govindasamy et al.‘‘Combined Climate and carbon-cycle effects of large-scale deforestation.’’ PNAS, Volume 104, no. 16. April 17, 2007. Archived online at: http://www.pnas.org/content/104/16/6550.abstract as of April 27, 2010.

ANSWERS TO POST-HEARING QUESTIONS

Dr. Robert Jackson, Nicholas Chair of Global Environmental Change, Professor, Biology Department, Duke University

Questions submitted by Chairman Brian Baird

Q1. You noted in your testimony that reflective materials over deserts would be an 

undesirable geoengineering strategy because of its harmful effects on ecosystems. 

Please elaborate upon this statement.

A1. This suggestion strikes me as a poor idea, environmentally and scientifically. 

Deserts are unique ecosystems with a diverse array of life. They are not a wasteland 

to be covered over and forgotten. 

Based on the best science available, I believe that placing reflective shields over 

deserts (and other comparable manipulative strategies) is likely to be both 

unsustainable and harmful to native species and ecosystems. Take as one example 

the suggestion to use a reflective polyethylene-aluminum surface. This shield would 

alter almost every fundamental aspect of the native habitat, from the amount of 

sunlight received (by definition) to the way that rainfall reaches the ground. Implemented over the millions of acres required to make a difference to climate, such a 

shield could also alter cloud cover, weather, and many other important factors. 

Examined from a different perspective, consider the recent public opposition to 

solar-thermal power facilities in California, Nevada, and other states. If siting relatively limited power facilities in desert ecosystems is difficult, how likely is the 

public to accept such a disruptive shield for thousands of square miles in the United 

States? Taxpayers in the United States deserve better solutions than proposals such 

as this one.

Q2. You described in your testimony the interrelated, and sometimes conflicting, impacts on atmospheric carbon concentration and surface albedo caused by largescale afforestation. While new forests sequester atmospheric carbon through photosynthesis, the dark growth can also decrease the local reflectivity, causing 

more sunlight to be absorbed. One article written by scientists at Lawrence 

Livermore National Lab,1 among others, suggests that because of this relationship, tropical afforestation would be very beneficial, but afforestation in temperate regions would be marginally useful. 

a. Do you agree with this assessment?

b. What geographic areas are, in general, most appropriate for afforestation, and 

what types should be avoided?

A2. My response below is a summary based on the information in Jackson et al. 

2008 (Jackson RB, JT Randerson, JG Canadell, RG Anderson, R Avissar, DD 

Baldocchi, GB Bonan, K Caldeira, NS Diffenbaugh, CB Field, BA Hungate, EG 

Jobba ́gy, LM Kueppers, MD Nosetto, DE Pataki 2008 Protecting Climate with Forests. Environmental Research Letters 3:044006). 

Based on decades of research in carbon sequestration and biophysics, we (the authors of the above paper) suggest that avoided deforestation, forest restoration, and 

afforestation in the tropics provide the greatest value for slowing climate change. 

Tropical forests combine rapid rates of carbon storage with biophysical effects that 

are beneficial in many settings, including greater convective rainfall. Forestry 

projects in warm-temperate regions, such as the southeastern US, can also help reduce warming, but large uncertainties remain for the net climate effects of forestry 

projects in temperate regions. Forestry projects in boreal systems are less likely to 

provide climate cooling because of the strong snow-cover feedback. Thus, incentives 

for reforesting boreal systems should be preceded by thorough analyses of the true 

cooling potential before being included in climate policies. 

Policies could also be crafted to provide incentives for beneficial management 

practices. For instance, urban forestry provides the opportunity to reduce energy use 

directly; in temperate regions deciduous trees block sunlight in summer, reducing 

the energy needed to cool buildings, but they allow sunlight to warm buildings in 

winter. In addition to choosing appropriate deciduous species, foresters could also 

select trees that are ‘brighter’, such as poplars, with albedos relatively close to those 

of the grasses or crops they replace. Additionally, forest planting and restoration can 

be used to reclaim damaged lands, reducing erosion and stabilizing streambanks. 
216

It is important to remember that trade-offs and unintended consequences are possible when forests are included in climate policies. The choice of tree species matters. Eucalypts, for instance, grow quickly and have a fairly bright albedo, but they 

are fireprone, can be invasive, and typically use more water than native vegetation. 

Because forestry projects can appropriate scarce water resources, they may be poor 

choices in drier regions. Applying fertilizers in forest sequestration projects helps 

trees grow more quickly but also increases the emissions of nitrous oxide, a potent 

greenhouse gas. Finally and perhaps most importantly, forests provide a wide range 

of important services, including preserving biodiversity, wildlife habitat, and freshwater supply. To the greatest extent possible, policies designed for climate change 

mitigation should not jeopardize other key ecosystem services.

Q3. In your testimony you recommended that the U.S. Global Change Research Program lead domestic geoengineering research efforts.

a. Is one or more of the existing interagency working groups within the 

USGCRP equipped to absorb geoengineering research? Or should one or more 

new working groups be created within the USGCRP to work on 

geoengineering?

A3. Aspects of the science of geoengineering cut across many of the working groups 

within USGCRP, including atmospheric composition, global carbon cycle, ecosystems, human contributions and responses, and land use and land cover change. 

For that reason, a new crosscutting working group may be needed. Complicating 

matters further, coordination with the U.S. Climate Change Technology Program 

(CCTP) on the technology of geoengineering will be equally important.

Q4. The Science and Technology Committee has held three geoengineering hearings, 

and each witness at each hearing has emphasized the deep distinctions between 

the two types of geoengineering: solar radiation management (SRM) and carbon 

dioxide removal (CDR).

a. If legislation were developed to facilitate geoengineering research, how should 

these distinctions be dealt with or accommodated?

b. For example, should CDR research initiatives be sited among existing activities at federal agencies, while SRM research is authorized separately under 

the umbrella of ‘‘geoengineering research?’’

A4. The federal government’s first priority for geoengineering research should be to 

provide incentives for carbon dioxide removal. The sooner we invest in, and make 

progress on, reducing greenhouse gas emissions today and promote ways to restore 

the atmosphere through carbon-removing technologies in the future, the less likely 

we are ever to need much riskier global sunshades. Our goal should be to cure climate change outright, not in treating a few of its symptoms. 

In a new paper in Issues in Science and Technology (Jackson and Salzman 2010 

Pursuing Geoengineering for Atmospheric Restoration), I coin the term ‘‘atmospheric 

restoration’’ as a guiding principle for prioritizing geoengineering efforts. The goal 

of atmospheric restoration is to return the atmosphere to a less degraded or damaged state and ultimately to its pre-industrial condition. Our climate is already 

changing, and we need to explore at least some kinds of carbon-removal technologies 

because energy efficiency and renewables cannot take carbon dioxide out of the air 

once it’s there. 

In response to your last question about where to place research initiatives, I have 

already stated that coordination through the USGCRP (and CCTP) is needed. If a 

different option is needed, some CDR activities could be sited within the Department of Energy. However, ocean fertilization is just one example of a CDR strategy 

that does not fit well in DOE and would be better placed in a different department 

or agency. 

I do not believe that a separate umbrella of ‘‘geoengineering research’’ should be 

authorized specifically for SRM activities. Such a stand-alone structure would give 

SRM greater visibility (and priority) than it deserves compared to CDR. It would 

also be counter-productive scientifically. Splitting CDR and SRM research may be 

desirable administratively; I simply take exception to the suggestion that CDM belongs in current agencies but SRM doesn’t and deserves its own structure. 
(217)

Appendix 2: 

ADDITIONAL MATERIAL FOR THE RECORD
218
219

GEOENGINEERING III: DOMESTIC AND 

INTERNATIONAL RESEARCH GOVERNANCE 

THURSDAY, MARCH 18, 2010

HOUSE OF REPRESENTATIVES, 

COMMITTEE ON SCIENCE AND TECHNOLOGY, 

Washington, DC.

The Committee met, pursuant to call, at 12:06 p.m., in Room 

2318 of the Rayburn House Office Building, Hon. Bart Gordon 

[Chairman of the Committee] presiding.
220
221

1 Chairman Willis will testify via satellite.

2The Royal Society (2009). Geoengineering the Climate: Science, Governance and Uncertainty. 

Edited by J. Sheperd et al., New York. 

HEARING CHARTER

COMMITTEE ON SCIENCE AND TECHNOLOGY

U.S. HOUSE OF REPRESENTATIVES 

‘‘Geoengineering III: Domestic and

International Research Governance’’

THURSDAY, MARCH 18, 2010

12:00 P.M.

2318 RAYBURN HOUSE OFFICE BUILDING

Purpose 

On Thursday, March 18, 2010, the House Committee on Science and Technology 

will hold a hearing entitled ‘‘Geoengineering III: Domestic and International Research Governance.’’ The purpose of this hearing is to explore the governance needs, 

both domestic and international, to initiate geoengineering research programs. Specifically, discussion will focus on governance to guide potential geoengineering research projects and which U.S. agencies and institutions have the capacity or authorities to conduct such research.

Witnesses

Panel I

• The Honorable Phil Willis, MP is the Chair of the Science and Technology 

Committee in the United Kingdom House of Commons.1

Panel II

• Dr. Frank Rusco is the Director of Natural Resources and Environment at 

the Government Accountability Office (GAO).

• Dr. Scott Barrett is the Lenfest Professor of Natural Resource Economics 

at the School of International and Public Affairs and the Earth Institute at 

Columbia University.

• Dr. Jane Long is the Deputy Principal Associate Director at Large and a 

Fellow for the Center for Global Strategic Research at Lawrence Livermore 

National Lab.

• Dr. Granger Morgan is the Department Head of Engineering and Public 

Policy and Lord Chair Professor in Engineering at Carnegie Mellon University.

Background 

Geoengineering can be described as the deliberate large-scale modification of the 

earth’s climate systems for the purposes of counteracting climate change. 

Geoengineering has recently gained recognition as a potential tool in our response 

to climate change. However, the science is new and largely untested and the international implications of research and demonstration are complex and often novel in 

nature. For these reasons, a pressing need for governance of geoengineering research has emerged. Geoengineering can be controversial because of the potential 

for environmental harm and adverse socio-political impacts, uncertainty regarding 

the effectiveness and cost of the technologies, the scale that may be needed to demonstrate the technology, and concern that the prospect of geoengineering may weaken current climate change mitigation efforts.2 These issues highlight the potential 

barriers to research as well as the need for governance of these emerging technologies. Experts are calling for a governance model or set of models that will allow 

the field to develop in an adaptive manner that facilitates development and explo-
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3Lenton and Vaughan (2008). A review of climate geoengineering options. Tyndal Centre for 

Climate Change Research, UEA. 4Formerly the U.K. Innovation, Universities, Science and Skills Committee. 

5The Royal Society (2009). 

ration of effective technologies that are environmentally and socially acceptable 

while being relevant for both domestic and international policy solutions. 

There is broad consensus among geoengineering experts that expansive reductions 

in greenhouse gas emissions must be made to limit the effects of climate change. 

However, political inertia and trends in greenhouse gas emissions indicate that traditional mitigation efforts may not provide an adequate response to mitigate the effects of climate change.3 Tools other than emissions reductions may be therefore 

needed. Proponents claim that geoengineering technologies, compared to traditional 

mitigation techniques, offer faster-acting, politically palatable, and cost-effective solutions. Only through research and testing can these assertions be validated or refuted. That said, greenhouse gas mitigation strategies alone may ultimately prove 

insufficient and the lead times that will be needed for sufficient geoengineering research, should it become necessary for deployment, may be years long. 

Today’s hearing is the third in a series of hearings that is intended to provide 

a forum for an open discussion of the merits and disadvantages of geoengineering 

research. These hearings are not intended to be an endorsement of geoengineering 

deployment.

Collaboration with the U.K. Science and Technology Committee 

The U.S. and the U.K. Science and Technology Committees have successfully built 

upon each other’s efforts to advance the international and domestic dialogues on the 

need for international collaboration on regulation, oversight, environmental monitoring, and funding of geoengineering research. In April of 2009, Chairman Gordon 

met with the Science and Technology Committee 4 of the U.K. House of Commons, 

chaired by the Honorable Phil Willis, MP. The chairmen agreed that their committees should identify a subject for collaboration. The U.K. Committee had recently 

published a report, Engineering, Turning Ideas into Reality, recommending that the 

government develop a publicly-funded program of geoengineering research. Given 

the international implications of geoengineering research and the authorities and interests of each committee, geoengineering emerged as an appropriate subject for collaboration by the chairmen. 

The chairmen coordinated the research and both committees have been in close 

communication throughout. The U.K. Committee established its terms of reference 

for its inquiry into the regulation of geoengineering, issued a call for evidence in 

November 2009, and is issuing a Committee report on the topic in March 2010. This 

report will be submitted as written testimony on behalf of Chairman Willis at today’s hearing. The official agreement between the U.S. and U.K. Committees, outlining the terms of work and collaborative agreement, will be included in the final 

hearing record. 

In the first session of the 111th Congress the U.S. Science and Technology Committee began a formal inquiry into the potential for geoengineering to be a tool of 

last resort in a much broader program of climate change mitigation and adaptation 

strategies. To initiate this, Chairman Gordon requested information on 

geoengineering from the Government Accountability Office (GAO) on September 21, 

2009. Dr. Frank Rusco, Director of Natural Resources and Environment at GAO will 

present the draft response to this request as his written testimony at today’s hearing. The Committee formally introduced the topic of geoengineering research in Congress on November 5, 2009 with a Science and Technology Full Committee hearing, 

‘‘Geoengineering: Assessing the Implications of Large-Scale Climate Intervention.’’ On 

February 4, 2010 the Energy and Environment Subcommittee held the second hearing in the series, ‘‘Geoengineering II: The Scientific Basis and Engineering Challenges.’’ Together with today’s hearing, this series of hearings serves as the foundation for an inclusive and transparent dialogue on geoengineering at the Congressional level.

Definition of Geoengineering 

Geoengineering technologies aim to intervene in the climate system through 

large-scale and deliberate modifications of the earth’s energy balance in order to reduce temperatures and counteract the effects of climate change.5 Most proposed 

geoengineering technologies fall into two categories: Carbon Dioxide Removal (CDR) 

and Solar Radiation Management (SRM). The objective of SRM methods is to reflect 

a portion of the sun’s radiation back into space, thereby reducing the amount of 
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6See the draft CRS report (2010) that is attached to this charter for descriptions of CDR and 

SRM technologies. 7For example, researchers at Rutgers University received a grant in 2008 to model stratospheric injections and sun shading. 

solar radiation trapped in the earth’s atmosphere and stabilizing its energy balance. 

CDR methods propose to reduce excess CO2 concentrations by capturing, storing or 

consuming carbon directly from air, as compared to direct capture from power plant 

flue gas and storage as a gas. CDR proposals typically include such methods as carbon sequestration in biomass and soils, modified forestry management, ocean fertilization, modified ocean circulation, non-traditional carbon capture, sequestration, 

distribution of mined minerals over agricultural soils, among others.6

The above definition of geoengineering may need to be modified going forward to 

create a more productive discourse on our response to climate change. CDR technologies remove excess amounts of CO2 from the air, thus presenting different hazards and risks than SRM technologies. In fact, many CDR technologies could be categorized with traditional carbon mitigation strategies, especially if they were undertaken at a small scale. For example, a mid-scale program for avoided reforestation 

does not carry the same risks as large-scale atmospheric sulfuric injections. In fact, 

such a program’s risks and challenges may not be greatly divergent from some traditional carbon management proposals, such as carbon credits. CDR technologies 

may not invoke the need for international governance instruments either. SRM approaches, on the other hand, call for the introduction of technologies into the environment; therefore, presenting novel challenges to governance and larger hurdles for 

basic research and risk assessment. Some experts suggest that the term 

‘‘geoengineering’’ encompass fewer of the more benign technologies discussed above. 

Coming to a resolution on appropriate terminology for this field may be a key step 

to increasing public understanding of geoengineering and assist the field in moving 

forward.

Domestic Research 

Although formal research in Federal agencies has been largely limited to a small 

number of National Science Foundation (NSF) grants to study closely-scoped issues 

related to geoengineering,7 it is clear that a number of Federal agencies have jurisdiction over one or more areas imbedded in geoengineering research. It is as yet unclear how Federal geoengineering research programs could be organized or allocated 

among Federal research bodies, as well as how non-governmental research consortia 

might contribute. The location of existing expertise in pertinent scientific and engineering fields, and the ability to execute comprehensive plans for interdisciplinary, 

inter-agency coordination would be key considerations in structuring domestic research in this area. Furthermore, it should be recognized that many of the developments and research activities needed for a formal geoengineering research program 

are also desirable for non-geoengineering purposes, such as general climate science 

research. 

The following are examples of how existing research capacities in Federal agencies 

could be engaged in geoengineering research from the basic science and engineering 

behind the technology, to quantifying its effectiveness, and to understanding the 

risk of such hazards as environmental impacts. 

The National Science Foundation (NSF) supports basic foundational research that 

may assist in the identification of the most promising geoengineering technologies. 

The Biological and Environmental Research program (BER) at the Department of 

Energy’s (DOE) Office of Science houses key expertise related to various elements 

of atmospheric and land-based geoengineering strategies. Satellite capabilities sited 

within the National Aeronautics and Space Administration (NASA) and the National Oceanic and Atmospheric Administration (NOAA) could help identify potential locations for land-based carbon management, inform atmospheric 

geoengineering approaches, and monitor large-scale land use changes. Climate modeling tools at NOAA, the Environmental Protection Agency (EPA) and DOE’s Office 

of Science could potentially be used to monitor large-scale demonstration projects. 

Such resources could also be used in a basic research setting for reverse climate 

modeling activities to project the potential impacts of decreased solar radiation and 

atmospheric carbon levels. High-end computing capabilities within the Office of 

Science at DOE, e.g., facilities located at Oak Ridge National Lab, may be suited 

to provide such highly detailed climate projections. 

For all CDR geoengineering strategies, a robust carbon accounting and 

verification program would be needed to ensure program effectiveness. Existing expertise in programs at EPA, the National Institute of Standards and Technology 

(NIST), and the Ameriflux and Atmospheric Radiation Measurement (ARM) pro-
224

8For example, the deployment of genetically engineered plants with increased albedo could invoke treaties such as the Convention on Biological Diversity of 1992. 9 CRS (2010). 

10The Royal Society (2009).

grams within the BER program at DOE could contribute to such a program. In addition, monitoring and verification tools such as NOAA’s Carbon Tracker and the Advanced Global Atmospheric Gases Experiment (AGAGE) at NASA could also be useful. More advanced and comprehensive tools may be needed, however. 

More specifically, the Forest Service and National Resource Conservation Service 

at the Department of Agriculture (USDA), the United States Geological Survey 

(USGS) at the Department of Interior, and DOE’s BER program could contribute 

expertise and management experience to land-based carbon reduction strategies 

such as afforestation, avoided deforestation, and biochar. NOAA’s expertise in oceanography at offices such as the Geophysical Fluid Dynamics Laboratory (GFDL) could 

contribute to ocean fertilization research. DOE’s Office of Fossil Energy (FE) and 

the National Energy Technology Laboratory (NETL) could leverage their capacity 

from such initiatives as FutureGen and the Clean Coal Power Initiative for air capture and non-traditional carbon sequestration research activities. And the Office of 

Basic Energy Sciences (BES) at DOE could inform the geological materials side of 

non-traditional carbon sequestration. 

The U.S. State Department would coordinate activities and agreements with foreign ministries for some geoengineering technologies. State Department involvement 

would depend, as noted, upon which activities are determined to impede upon existing international agreements or be associated with trans-boundary impacts. In addition, the involvement of more cabinet-level departments and Federal agencies may 

be useful for effective development of geoengineering research given the potential 

for associated agricultural, economic, international security, and governance effects.

Criteria for Governance Development 

Criteria to consider regarding the impacts of geoengineering technologies include: 

whether they are international or trans-boundary in scope; whether they dispense 

hazardous material into the environment or create hazardous conditions; and 

whether they directly intervene in the status of the ecosystem. 

Governance needs for geoengineering research will likely differ based on the technology type, the stage of research, the target environment (e.g., the high seas, space, 

land, atmosphere), and where potential impacts may occur. As noted above, SRM 

and CDR technologies may have differing regulatory needs. CDR technologies that 

are similar in scope to most of those proposed today could be governed by existing 

U.S. laws and institutions. An exception to this would possibly be enhanced weathering in oceans and ocean fertilization techniques (both are CDR technologies), 

which may require international governance structures due to the potential for 

trans-boundary ecosystem impacts. SRM technologies, on the other hand, are more 

likely to require international governance for research. For example, two proposed 

SRM technologies, marine cloud whitening and atmospheric injections of sulfur particles would likely take place in an area governed by the international community, 

disperse trans-nationally, and have trans-national effects. Other SRM technologies 

such as land surface albedo modification may have lesser need for international governance.8 Different governance needs will also become apparent as research develops from modeling, to assessments, and finally to field trials. Built-in flexibility and 

feedback mechanisms throughout the research process will assist in the effective development and governance of these emerging technologies. Lastly, different environments for research and demonstration are likely to require different governance 

strategies. Activities that take place in or affect the high seas or space versus the 

lower atmosphere, terrestrial, and near-shore areas will fall under different jurisdictions with different legal authorities. 

Governance Options 

Possible options for governance are outlined below. Please refer to the attached 

draft Congressional Research Service (CRS) report 9 and The Royal Society’s study 10

for further information. 

No Regulation 

Governments could fully refrain from all governance of geoengineering, allowing 

the field to develop at will under existing frameworks. Advocates of this approach 

see private efforts as the best avenue to pursue research and development. Advocates of the ‘‘no regulation’’ approach may see government involvement as a stamp 
225

11See the draft CRS report (2010) that is attached to this charter for descriptions of CDR and 

SRM technologies. 12Lenton and Vaughan. (2008).

of approval for potentially unfavorable technologies. It is important to note that this 

approach essentially results in an unregulated research environment for largely new 

and unproven technologies, whose impacts are uncertain and may be unevenly distributed, even from small demonstration projects.

International Treaties and Agreements 

At this time, no international treaties or institutions exist with sufficient mandate 

to regulate the full suite of current geoengineering technologies.11 Although no existing international agreements or treaties govern geoengineering research by name, 

existing institutions could theoretically be modified to incorporate this field. For example, the U.N. Framework Convention on Climate Change (UNFCCC) may serve 

as a potential governing body for geoengineering. Another suggestion is that the 

Intergovernmental Panel on Climate Change (IPCC) could establish a technical 

framework to determine where the research should be focused and what technologies are scientifically justified. 

Treaties for geoengineering research governance may be inappropriate at this 

time as the field encompasses many emerging technologies. In such a situation, 

treaty discussions could lead to a moratorium on research because nations often negotiate based on what their capacity for research, development, deployment and assessment is today, which in most cases is limited. Proponents of a moratorium argue 

that the potential risks of these technologies are just too great. Alternatively, some 

suggest that a research moratorium would be ill-advised because it would prematurely inhibit the generation of scientific knowledge and fail to discourage potentially dangerous experimentation by less responsible parties. It could limit society’s 

ability to gather the information necessary to make informed judgments about the 

feasibility or acceptability of the proposed technologies. A moratorium could also 

deter responsible parties while failing to dissuade potentially dangerous experimentation by less responsible parties.

International Research Consortia 

Given how little is understood about the scientific, technical, and social components of proposed geoengineering technologies, crafting appropriate governance 

through new or existing treaties may be difficult. International research consortia 

such as the World Climate Research Program (WCRP) could be used effectively to 

safely advance the science while building a community of responsible researchers. 

This would essentially provide a middle ground between the no regulation and international treaty options. Past experiences show that international research consortia 

(e.g., the Human Genome Project and the European Organization for Nuclear Research) can succeed at prioritizing research for emerging technologies, developing effective and objective assessment frameworks, providing independent oversight of 

evolving governance needs, and developing voluntary codes of practice to govern 

emerging technologies.

Conclusions 

Some geoengineering technologies appear to be technically feasible; however, 

there is high uncertainty regarding their effectiveness, costs, environmental effects, 

and socio-political impacts. Appropriate governance structures that allow for an 

iterative exchange between continued public dialogue and further research are needed to determine if such technologies are both capable of producing desired results 

and socially acceptable. Climate change is a global problem that impacts people and 

ecosystems at the local scale. If traditional mitigation efforts are not effective on 

their own,12 we will need alternatives at the ready. In the next decade the debate 

over geoengineering will intensify. Research will lead to increasingly plausible and 

economically feasible ways to alter with the environment. At the same time, political 

and social pressure will grow—both to put plans into action (whether multi- or unilaterally), and to limit the development of geoengineering research. These issues led 

the U.K. and U.S. Science and Technology Committees to jointly consider the role 

for potential governance structures to guide research in the near term and to oversee potential demonstration projects in the long term. 
226

Chairman GORDON. Good morning and welcome to this hearing 

on and discussion with domestic and international research governance of geoengineering. And let me give a little preface, particularly to our guest, Chairman Willis. We are going to be having 

votes around our time, 12:30 or 1:00. You know what that is like, 

when the bells go off, so it is our hope to move forward with your 

first part of this hearing, and as we go along, we will have a little 

better understanding. 

Our changing climate has been the topic of sometimes heated 

discussion by some of our committee’s hearings. It is understandable. As with any field of science, climate service, or climate 

science, will continue to evolve over time to provide an ever-greater 

level of accuracy for findings and forecasts. 

However, in my opinion, one thing is now clear. The overwhelming preponderance of data indicates that global climate is 

changing, that humans are at least partially responsible, and that 

we can best mitigate the damage by reducing our emissions of 

greenhouse gases such as carbon dioxide. 

Additionally, I am concerned that the impacts of climate change 

could outpace the world’s political, economic, and physical ability to 

avoid them through greenhouse gas reductions alone. Therefore, we 

must know what other tools we have at our disposal. Certain proposals for deliberate modification of the climate, otherwise known 

as geoengineering, represent one option. But we cannot know until 

we have done the research on the full range of impacts of global 

engineering. 

It will take substantial time and research to determine whether 

these new technologies can develop appropriately, whether there is 

an appropriate governance structures, and to test them, to see 

what potential benefits and hazards may be posed. 

As the Chairman of the committee of jurisdiction, my interest is 

to provide a forum for open and honest discussion of 

geoengineering, just as we will have on nuclear power, on carbon 

capture and sequestration, other energy sources, as well as other 

types of mitigation. 

And today, we are here to discuss the matters of domestic and 

international governance of geoengineering research programs. 

With that, I would like to thank our excellent witness, Chairman 

Willis, for appearing before this committee, and I yield to the distinguished Ranking Member, Mr. Hall, for his opening remarks. 

[The prepared statement of Chairman Gordon follows:]

PREPARED STATEMENT OF CHAIRMAN BART GORDON

Good Afternoon. I want to welcome everyone to today’s hearing to discuss the Domestic and International Research Governance of Geoengineering. 

Our changing climate has been the topic of sometimes heated discussion at some 

of our Committee’s hearings. 

It is understandable—As with any field of science, climate science will continue 

to evolve over time to provide an even greater level of accuracy in its findings and 

forecasts. 

However, in my opinion one thing is clear now—the overwhelming preponderance 

of data indicates that the global climate Is changing, that humans are at least partially responsible, and that we can best mitigate the damage by reducing our emissions of greenhouse gases such as Carbon Dioxide. 

Additionally, I am concerned that the impacts of climate change could outpace the 

world’s political, economic, and physical ability to avoid them through greenhouse 

gas reductions alone. 
227

Therefore, we must know what other tools we have at our disposal, and if certain 

proposals for deliberate modification of the climate, otherwise known as 

geoengineering, represent an option. 

But we cannot know until we have done the research on the full range of impacts 

of geoengineering. 

It will take substantial time to research these new technologies, to develop appropriate governance structures, and to test them to see what potential benefits and 

hazards they may pose. 

As the Chairman of the Committee of jurisdiction my interest is in providing a 

forum for an open and honest discussion of geoengineering, just as we will do for 

nuclear engineering, carbon caption sequestration, and other complex engineering 

subjects. 

Today we are here to discuss matters of domestic and international governance 

for geoengineering research programs.

Mr. HALL. Thank you, Mr. Chairman, and but for my respect for 

you, I would have a lot longer opening remark here, but I would 

just say that I believe this is the third hearing our committee has 

held on geoengineering. 

As I have expressed on previous occasions, I have significant reservations about pursuing this line of research. With that, in the interest of time and courtesy to our very distinguished guest, I will 

just put this in the record. 

You can read it later, if you would like to. 

[The prepared statement of Mr. Hall follows:]

PREPARED STATEMENT OF REPRESENTATIVE RALPH M. HALL

Thank you, Mr. Chairman. I believe this is the third hearing our Committee has 

held on geoengineering. As I have expressed on previous occasions, I have significant reservations about pursuing this line of research. 

The debate about climate change is far from over. This statement is even more 

true today given the several admissions by the Intergovernmental Panel on Climate 

Change, or IPCC, since the end of last year, regarding mistakes, miscalculations 

and the use of non-peer reviewed science in the 4th Assessment Report. Despite 

many assurances that the base science has not been compromised, our faith in the 

scientific community when it comes to climate change research has been severely 

shaken. We are now facing an onslaught of regulations that could severely harm our 

economy based upon this science that has now come into question. 

Today’s hearing focuses on domestic and international research governance of 

geoengineering. Although I think it is premature to be wading into this aspect of 

geoengineering—we have yet to agree on whether or not we should pursue this—

there are several hurdles that would need to be overcome in order to implement any 

type of governance structure. On the domestic side, there is no way to truly verify 

the science without conducting experiments. Like every other test that could potentially effect the environment, an Environmental Impact Assessment would have to 

be conducted in order to comply with current law. 

Since a geoengineering experiment is supposed to affect the environment, I am 

not sure that such an Assessment could successfully meet current standards under 

the National Environmental Protection Act (NEPA), as this law has been interpreted over time to ensure that any impact on the environment is minimized or 

eliminated. 

Internationally, I find it hard to believe that there would be any kind of consensus 

on this issue. 

And, as we witnessed with the Copenhagen conference last December, when a 

larger consensus breaks down, a small group of nations may try to work out a deal 

amongst themselves. If world leaders decide to come together and seriously discuss 

geoengineering, it could force a situation where some nations feel justified embarking on their own program. Geoengineering could have global repercussions, so it is 

especially troubling that one or more nations could band together to produce an outcome that could have global implications, such as attempting to mimic a volcanic 

eruption. 

So, Mr. Chairman, while I am interested in the testimony of our witnesses today, 

I must state that I am skeptical of this research and wary of the potential diplomatic minefield we may be stumbling into if we pursue this. I look forward to hearing from our distinguished witnesses.
228

[The prepared statement of Mr. Costello follows:]

PREPARED STATEMENT OF REPRESENTATIVE JERRY F. COSTELLO

Good Afternoon. Thank you, Mr. Chairman, for holding today’s hearing to discuss 

the governance of potential geoengineering research projects in the U.S. and abroad. 

Global climate change is an international issue that will require an international 

response. For this reason, I am pleased to welcome our colleagues from the United 

Kingdom with whom this Committee has worked to explore the potential of 

geoengineering as a means of reducing greenhouse gas emissions. 

Geoengineering could have a global impact on our atmosphere, oceans, and land. 

Because these techniques have the potential to change the chemical make-up of the 

earth, international cooperation and governance of the research will be necessary. 

In particular, it will be important to have the involvement of as many international 

partners as possible. I would like to hear how all countries, including less developed 

countries that have been reluctant to work on climate change mitigation in the past, 

may engage in geoengineering research. Further, I would like to know what international organizations would best be suited to take the lead in governing this research. 

In addition, geoengineering remains in its earliest stages of research and development, but there are significant concerns about the safety and reliability of 

geoengineering. I would like to know how the international community may address 

these safety risks should geoengineering research move forward. 

I welcome our two panels of witnesses, and I look forward to their testimony.

Chairman GORDON. Without objection. Thank you, Mr. Hall. And 

now, it is my pleasure to introduce our witness at this time. Member of Parliament Phil Willis is the Chairman of the United Kingdom’s House of Commons Science and Technology Committee. 

Chairman Willis has represented the constituency of Harrogate 

and Knaresborough in the Parliament since 1997. Before his election to the House of Commons, Chairman Willis served as a distinguished educator in U.K. schools for over 35 years, 20 of those 

years as head teacher at a large comprehensive school. 

During his tenure in Parliament, Chairman Willis has been a 

champion for inclusive childhood education, vocational training, 

and affordable university tuition. I am honored to have or embarked upon these joint activities with your committee during each 

or our last terms. 

We thank you for your commitment to this inquiry and appearing before us today. 

And let me remind everyone here today, this is a very historic 

and unique hearing that we are having. To the best of my knowledge, it is the first time that two committees, similar committees, 

in this case, the Science and Technology Committee within Congress and the U.K., have agreed to have a joint hearing, or I guess 

I should say parallel hearings on a topic from which there will be 

brought back information, not as a legislative proposal, but rather, 

as a potential recommendation. 

So, again, this is historic, and Chairman Willis, I appreciate you 

being a part of this. Your written testimony will be included in the 

record, and now, we welcome you to begin your oral testimony. 

Let us see. Mr.—Chairman Willis, do you hear us now? Hold 

your hand up if you can hear us. Well, we know we have a time 

delay, but not that much? Larry, what do you think? Let us—once 

again, Chairman Willis, can you—raise your hand if you can hear 

me. 

Well, again, do we have Larry around, or has he escaped? I can 

understand him trying to get away. I see Chairman Willis’ lips, but 

I can’t read them. So, let me suggest to the staff—are we having 
229

a parallel telephone conversation with them, or internet conversation? Okay. 

Well, I am going to try one more time. Mr. Willis, if you could 

hear me, raise your hand. I don’t see it. So, why don’t I suggest 

that our other—our Panel II come forward, and whatever—I wish 

there was a way that we could—we don’t have any kind of parallel 

communication? 

Okay, Larry, what do you think? Okay. Chairman Willis, can you 

hear me? Raise your hand if you can. 

Chairman WILLIS. I certainly can. 

Chairman GORDON. Oh, good. Good. 

Chairman WILLIS. Barely hear you. 

Chairman GORDON. Well, you may have missed the well-deserved 

glorious introduction that I had given you earlier, as well as the 

statement of the uniqueness and historic aspect of this hearing. 

There is another historic matter going on right now, and that is a 

healthcare debate in Congress. 

Our phone lines are being jammed, we had 40,000 yesterday, so 

it is making all communication difficult, but as we pointed out earlier, if we could get to the Moon, we should be able to complete this 

hearing. 

And so, with that, I welcome you to begin. 

STATEMENT OF HON. PHIL WILLIS, MP, CHAIRMAN, SCIENCE 

AND TECHNOLOGY COMMITTEE, UNITED KINGDOM HOUSE 

OF COMMONS 

Chairman WILLIS. Well, first of all, thank you very much indeed, 

Chairman Gordon. I was making the comment that if we can’t get 

this to work, then geoengineering is a long way off the agenda. 

But may I commence by saying how honored I am to appear before the U.S. House of Representatives Science and Technology 

Committee. And this, as I am probably—I am sure you said in 

Washington, is a first for our Committees, and I trust that the 

level of cooperation between our Committees can be continued after 

our general election, which occurs in, probably, May of this year. 

This inquiry really began right in April 2009, when we visited 

Washington, D.C., and your Chairman, Bart Gordon, and we discussed the possibility of a joint inquiry. My fellow Committee Members and I are delighted that we have managed, within the constraints of procedure, to undertake something that approached a 

joint inquiry. 

I state in the record that our staff have found your staff to be 

absolutely superb to work with, highly professional, exceedingly 

helpful, and knowledgeable. And we, as a committee, have thoroughly enjoyed the process of dovetailing our inquiry on 

geoengineering specifically to fit into your larger inquiry into the 

wider issues of geoengineering. I would very much hope that this 

relationship between our two committees is something that can 

outlast my, and indeed your, tenure. 

Today, we published in London our report, The Regulation of 

Geoengineering, and geoengineering is a topic that, as a committee, 

we have been interested in for a while. We were, I believe, the very 

first legislature to examine geoengineering, which we did as part 

of a larger report on engineering itself. 
230

In that report, we urged the U.K. government to consider the full 

range of policy options for managing climate change, and that includes various geoengineering options as potential Plan Bs, in the 

event that Plan A, mitigation and adaption, was not sufficient. 

We divided geoengineering into technologies that reduce solar radiation, SDM or SRM, as I think you call it, that is, to keep the 

Earth cooler by reflecting more of the Sun’s energy, and carbon sequestration, that is, taking carbon out of the atmosphere to reduce 

the greenhouse effect. 

We cautioned against mass roll-outs without extensive research, 

and suggested that our U.K. Research Council fund research on 

modeling the effects of geoengineering and to start a public debate 

on the use of geoengineering techniques, both of which, I am 

pleased to say, are now underway. 

Following that inquiry, the Royal Society produced a report on 

geoengineering, an excellent report that details the scientific and 

technological issues and options, and I believe that you took evidence from Professor John Shepherd, who was Chairman of the 

Royal Society’s geoengineering panel. 

One of the key recommendations from the Royal Society’s report 

was that the regulation of geoengineering required careful consideration. We decided, as part of a dovetailing exercise with your 

committee, to take on that challenge and move the debate on the 

regulation of geoengineering a little further. 

The first question in our terms of reference for this inquiry was, 

is there a need for international regulation of geoengineering research and deployment? And if so, what international regulation 

mechanisms need to be deployed? We discovered two things. First, 

such geoengineering techniques are already subject to regulation. 

In fact, there is a lot of regulation in this field. For example, ocean 

fertilization is being managed by the London Convention on Ocean 

Dumping under the London Protocol, and existing international 

regulatory arrangements, such as the U.N. Framework Convention 

on Climate Change, could relatively easily incorporate some 

geoengineering techniques, particularly carbon dioxide removal 

technologies. 

Second, with regard to remaining techniques, such as stratospheric aerosols or space mirrors, it is not clear that existing treaties could be adequately altered to encompass them, and they 

would need looking at afresh. 

Additionally, particularly for technologies such as injecting 

aerosols into the stratosphere, the costs are relatively low, which 

means that a rich country might be able to engage in this kind of 

activity unilaterally. And the effects are not predictable, and cannot be contained with national boundaries. We should be keen, 

therefore, to avoid a situation where one nation, deliberately or 

otherwise, alters the climate of another nation without prior agreement. 

We concluded that, and I quote: ‘‘The science of geoengineering 

is not sufficiently advanced to make the technology predictable, but 

this, in itself, is not grounds for refusing to develop a regulatory 

framework. There are good scientific reasons for allowing investigative research to proceed effectively to devise and implement some 

regulatory frameworks, particularly for those techniques that a sin-
231

gle country or small group of countries could test or deploy and impact the whole climate.’’

We also concluded that there is a need to develop a regulatory 

framework for geoengineering. Whether our existing international 

regulatory regimes, which need to develop a focus on 

geoengineering, or some regulatory systems that need to be designed and implemented for those solar radiation management 

techniques that currently fall outside any international framework. 

Having decided that there is a need for regulatory regimes for 

geoengineering, we considered what principles might govern them. 

So, a group of academics from universities at Oxford, University 

College London and Cardiff, came up with a set of five principles, 

of which we are very supportive. 

And these principles are: First, that geoengineering should be 

regulated as a public good, and we need to define what a public 

good is. Second, that public participation in geoengineering and decision-making is absolutely essential. If we don’t take people with 

us, we may well lose the argument. Third, that disclosure of 

geoengineering research and open publication of results is absolutely essential if we are going to take the scientific community 

with us, and particularly, if we are going to take the public with 

us. Fourth, independent assessment of impacts. Peer review in this 

area is crucially important. And finally, governance before deployment, that we make sure that we have a framework before, in fact, 

there is major deployment. 

May I conclude with a few specifics that might be of interest to 

your inquiry? 

Following careful consideration of a wide range of views on 

geoengineering, we concluded the following. First, regarding research that uses computers to model the impact of geoengineering 

technologies, we wholeheartedly support that work, so long as it 

adheres to principle three on the disclosure and open publication 

of results. 

We thought that even a short-term ban on solar radiation management research would be a mistake, largely, because it would be 

unenforceable, and therefore, having bans would not work. 

Third, it seems sensible that if small-scale testing of solar radiation management geoengineering is going to take place, it should 

adhere to the full set of principles that I just outlined, and there 

should be negligible or predictable environmental impact as far as 

is possible, and that there should be no trans-boundary effects. 

Fourth, it would be prudent for researchers exploring the impact 

of geoengineering techniques to make a special effort to include 

international expertise, and particularly, scientists from the developing world, which is most vulnerable to climate change. 

And finally, we concluded that, and I quote: ‘‘Any testing that 

has impacts on the climate,’’ that is large scale enough to have a 

real impact on the wider climate, must be subject to an international regulatory framework. 

May I finish my comments, Mr. Chairman, by making some 

broader observations? We found this to be a hugely complex area. 

International agreements are not always easy for noncontroversial 

issues, but climate change, which is a controversial issue, because 

of the impact that mitigation efforts might have on our economies, 
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1The Science and Technology Committee, The Fifth Report of Session 2009–10, The Regulation of Geoengineering, HC 221

has proven very difficult to get international agreement on, as we 

saw recently at Copenhagen. 

I cannot see how geoengineering could be any easier, but that 

should not be a reason to back off. If the climate warms dangerously, and we can’t fix the problem by reducing carbon emissions or adapting to the changing climate, geoengineering might be 

our only chance. 

It would be irresponsible of us not to get the ball rolling on regulation. And to that end, we considered the only appropriate forum 

for managing something like geoengineering would be the United 

Nations. Geoengineering covers such a wide range of technologies 

that more than one international body would be required to work 

on international agreements. And we suggested that the U.K. government—and it is something it might be able to do in partnership 

with the U.S. government—should one, press hard for a suitable 

international body to commission a review of how geoengineering 

regulation might work in practice, and two, we should press hard 

for the establishment of an international consortium to explore the 

safest and most effective geoengineering options. 

Thank you very much indeed, Mr. Chairman. 

[The prepared statement of Chairman Willis follows:]

PREPARED STATEMENT OF PHIL WILLIS

INTRODUCTION

This inquiry really began life in April 2009, when we visited Washington DC and 

met with your Chairman, Bart Gordon. We discussed then the possibility of a joint 

inquiry. My fellow committee members and I are delighted that we have managed—

within the restraints of procedure—to undertake something that approached a ‘joint’ 

inquiry. 

May I state for the record that our staff have found your staff to be terrific to 

work with, professional, helpful and knowledgeable. 

And we as a committee have thoroughly enjoyed the process of dovetailing our inquiry on geoengineering specifically to fit neatly into your larger inquiry into 

geoengineering issues more broadly. I very much hope that this relationship between the two committees is something that outlast mine and Bart’s tenures.

BACKGROUND

Today we published our Report, the Regulation of Geoengineering.1

Geoengineering is a topic that as a committee we have been interested in for a 

while. We were, I believe, the very first legislature to examine geoengineering, 

which we did as part of a larger report on engineering. In that report we urged the 

U.K. Government to consider the full range of policy options for managing climate 

change, and that includes various geoengineering options as potential ‘‘plan B’’, in 

the event of ‘‘plan A’’—mitigation and adaptation—not being sufficient. 

We divided geoengineering into technologies that reduce solar insolation (that is, 

keep the earth cooler by reflecting more of the sun’s energy) and carbon sequestration (that is, taking carbon out of the atmosphere to reduce the greenhouse effect). 

We cautioned against mass rollout without extensive research and suggested that 

our U.K. research councils fund research on modelling the effects of geoengineering 

and start a public debate on the use of geoengineering techniques—both of which 

are now underway. 

Following that inquiry, the Royal Society produced a report on geoengineering—

a fine report that detailed the scientific and technological issues and options—and 

I believe that you took evidence from Professor John Shepherd, who was chairman 

of the Royal’s geoengineering panel. 

One of the key recommendations from the Royal’s report was that the regulation 

of geoengineering required careful consideration. We decided—as part of a dove-
233

tailing exercise with your committee to take on that challenge and move the debate 

on the regulation of geoengineering a little further.

A NEED FOR REGULATION?

The first question in our terms of reference for this inquiry was: is there a need 

for international regulation of geoengineering research and deployment and if so, 

what international regulatory mechanisms need to be developed? We discovered two 

things. 

First, some geoengineering techniques are already subject to regulation. For example, ocean fertilisation is being managed by the London Convention on ocean 

dumping under the London Protocol. And existing international regulatory arrangements such as the UN Framework Convention on Climate Change could relatively 

easily incorporate some geoengineering techniques such as carbon dioxide removal 

technologies. 

Second, as regards the remaining techniques—such as stratospheric aerosols or 

space mirrors—it is not clear that any existing treaties could be adequately altered 

to encompass them. Additionally, particularly for technologies such as injecting 

aerosols into the stratosphere, the costs are relatively low—which means that a rich 

country might be able to engage in this kind of activity unilaterally-and the effects 

are not predictable and cannot be contained with national boundaries—we should 

be keen to avoid a situation where one nation deliberately or otherwise alters the 

climate of another nation without prior agreement. 

We concluded that ‘‘the science of geoengineering is not sufficiently advanced to 

make the technology predictable, but this of itself is not grounds for refusing to develop regulatory frameworks. There are good scientific reasons for allowing investigative research and better reasons for seeking to devise and implement some regulatory frameworks, particularly for those techniques that a single country or small 

group of countries could test or deploy and impact the whole climate.’’

We also concluded that there is a need to develop regulatory frameworks for 

geoengineering. There are existing international regulatory regimes, which need to 

develop a focus on geoengineering. And some regulatory systems need to be designed and implemented for those solar radiation management techniques that currently fall outside any international regulatory framework.

PRINCIPLES FOR GEOENGINEERING REGULATIONS

Having decided that there is a need for regulatory regimes for geoengineering we 

considered what principles might govern them. A group of academics from Oxford, 

University College London and Cardiff came up with a set of five principles of which 

we are very supportive. These principles are:

- geoengineering to be regulated as public good

- public participation in geoengineering decision-making

- disclosure of geoengineering research and open publication of results independent assessment of impacts, and

- governance before deployment.

We made a series of recommendations on the basis of these excellent suggestions. 

1. Geoengineering should be for the public good. That is a given. And therefore 

any regulations should support this position. However, we suggested that for the 

sake of clarity,‘‘public good’’ should be defined; after all, there are many different 

‘‘publics’’—some would benefit from global warming and they might not be too 

pleased with geoengineering deployment. We also noted that striving to make 

geoengineering for the ‘‘public good’’ might risk intellectual property rights, and that 

would be a shame. No IP means no industrial and private sector input; and without 

industrial input, a lot of these technologies might never get off the ground. 

2. We are in favour of public consultation, but a bit cautious about ‘‘public participation in . . . decision-making’’. For example, could people who were adversely affected by geoengineering—even if the majority of people benefited—veto or alter 

geoengineering tests? 

3. Our support for the notion of full disclosure of geoengineering research and the 

open publication of results is unqualified. In fact, we went further and suggested 

that an international database of geoengineering research to encourage and facilitate disclosure might be useful. 

4. The called for ‘‘independent assessment of impacts’’ is very important. Independent assessment is a key scientific concept—it takes the task of assessing the 

effectiveness of an intervention away from its inventors. That is a good thing. However, we do think that the term ‘impacts’ covers a range of issues. For example, de-
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ployment of geoengineering might occur only when temperatures go past a dangerous point of warming, say 3.5 degrees centigrade, so our definition of impact 

would need honing. Another issue it raises is compensation for people that suffer 

because of geoengineering. This legal aspect of geoengineering is unavoidable and 

central to the reasons why good regulation is necessary. 

5. The last of the principles, ‘‘governance before deployment’’, again, we support 

without qualification. We suggested that our government commission research and 

press for research to be carried out through international bodies on the legal, social 

and ethical implications of geoengineering.

SPECIFICS

May I conclude with a few specifics that may be of interest to your inquiry? Following careful consideration of a wide range of views on geoengineering, we concluded the following:

- regarding research that uses computers to model the impact of geoengineering 

technologies, we support that work-so long as it adheres to principle 3 on the 

disclosure and open publication of results;

- we thought that even a short-term ban on all solar radiation management research would be a mistake, at least in part because it would be unenforceable;

- it seems sensible that if small-scale testing of solar radiation management 

geoengineering is going to take place it should adhere to the full set of principles that I just outlined, that there should be negligible or predicable environmental impact as far as is possible, and that there should be no transboundary effects;

- it would be prudent for researchers exploring the impact of geoengineering 

techniques to make a special effort to include international expertise, and particularly scientists from the developing world which is most vulnerable to climate change; and

- finally, we concluded that ‘‘any testing that impacts on the climate’’-that is, 

that is large-scale enough to have a real impact on the wider climate-’’must 

be subject to an international regulatory framework’’.

CLOSING

May I finish my comments, Chairman, by making some broader observations. We 

found this to be a very complex area. International agreements are not always easy 

for non-controversial issues. Climate change, which is a controversial issue because 

of the impact that mitigation efforts might have on our economies, has proven very 

difficult to get international agreement on. I cannot see how geoengineering would 

be any easier. 

But that should not be a reason to back off. If the climate warms dangerously, 

and we can’t fix the problem by reducing carbon emissions or adapting to the changing climate, geoengineering might be our only chance. It would be irresponsible for 

us not to get the ball rolling on regulations. 

To that end, we considered that the only appropriate forum for managing something like geoengineering would be the U.N. Geoengineering covers such a wide 

range of technologies that more than one international body would be required to 

work on international agreements. We suggested that the U.K. government—and 

this is something it might be able to do in partnership with the U.S. government—

should (1) press hard for a suitable international body to commission a review of 

how geoengineering regulations might work in practice; and (2) press hard for the 

establishment of an international consortium to explore the safest and most effective 

geoengineering options.

BIOGRAPHY FOR PHIL WILLIS

Phil Willis was born in Burnley, Lancashire. At school he excelled in sport and 

at one time was a trialist for Burnley FC. He went to study History and Music at 

the City of Leeds and Carnegie College, qualifying as a teacher in 1963 from the 

University of Leeds Institute of Education. Later in his career he was seconded to 

Birmingham University where he gained a B.Phil. degree with distinction in 1978. 

Phil’s teaching career was mostly spent in Leeds where he rose rapidly from Assistant Master at Middleton Secondary Boys’ School in 1963 to become Deputy 

Headteacher at West Leeds Boys’ Grammar School in 1974, Perhaps his most rewarding period was spent at Primrose Hill High School in the Chapletown district 
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of Leeds where for seven years he was involved in multi-cultural education and outreach youth work. 

In 1978 he became head of Ormesby School in Middlesbrough where he helped 

pioneer the integration of children with physical disabilities into mainstream education. In 1983 he returned to Leeds as Head of one of the city’s largest comprehensive schools, John Smeaton Community High School. Situated in one of the more 

deprived areas of Leeds, he continued his mission, for ’inclusive’ education. 

He became nationally recognised for the inclusion of children with severe learning 

difficulties and others with sensory impairments into mainstream education. Prior 

to his election to Westminster he was involved with another pioneering development—‘The family of Schools’ initiative—which brought together all agencies concerned with developing first class opportunities for children from disadvantaged 

backgrounds. 

Phil joined the Liberal party in 1985 and was elected to Harrogate Borough Council in 1988. He became leader of the Council in 1990 and following his election to 

North Yorkshire County Council in 1993 became Deputy Group Leader. 

His period as Leader of Harrogate Council coincided with an unprecedented rise 

in Liberal Democrat representation and he is credited with many of the economic 

generating initiatives which have made the area one of the top earners in the country. His most notable success was turning the famous Harrogate Conference Centre 

from a loss making ‘white elephant’ into a £1m a year success story. 

At Westminster, he was appointed Shadow Secretary of State for Education and 

Skills in 1999 retaining the post until 2005, when he was appointed Chairman of 

the House of Commons Science and Technology Select Committee. In May 2007 he 

was also appointed Chair of the Joint Committee on the Draft Human Tissue and 

Embryos Bill. In November 2007 the Science and Technology Select Committee was 

disbanded and the House of Commons Innovation, Universities, Science and Skills 

Select Committee was formed; Phil Willis was elected chairman soon after. 

In the summer 2009 departmental reshuffle the department for Innovation, Universities and Skills was disbanded, along with its corresponding Select Committee. 

Following a hard-fought campaign from Phil and leading members of the Science 

community, the Science and Technology Select Committee was re-created on October 

1st, with Phil elected as Chairman. 

Married with two children, Phil is a keen supporter of Leeds United and spends 

much of his spare time in Ireland where he retains an interest in his family’s farm 

in Donegal

Also submitted for the record by Chairman Willis:

United Kingdom House of Commons Science and Technology Committee. The Regulation of Geoengineering. Fifth Report of Session 2009–10. London: The Stationery 

Office Limited. 10 March 2010. 

This report, totaling 119 pages, is available in its entirety archived online as of 

June 21, 2010 at http://democrats.science.house.gov/Media/file/Commdocs/hearings/2010/Fu11/18mar/UKR¥Regulation¥of¥Geoengineering¥report.pdf. The full 

report should be considered Chairman Willis’ full submission for the hearing record.

Attached here are:

I. Table of Contents

II. Executive Summary

III. Introduction
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DISCUSSION

Chairman GORDON. Well, thank you, Chairman Willis, for that 

very good presentation. 

We received your report, I think, 130 pages, today, which we are 

starting to go through. 

INTERNATIONAL RESEARCH DATABASE

I certainly concur with you that geoengineering is controversial, 

both on the left and the right. It is, and I concur that it is something that we hope that will never take place, but it would be irresponsible for us not to start at least looking at the foundation for 

potential research. 

I think any implementation is decades out, but you have to start 

somewhere. And so, we very much appreciate your participation, 

and that of your excellent staff. 

Now, we will at this point move to the first round of questions, 

and the Chair will recognize himself for five minutes. As you mentioned in your testimony, you felt that an international database 

would be a very good way to have a tool for transparency and public understanding. 
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Do you have any suggestions on how that database might be developed or how it would work? 

Chairman WILLIS. Well, first of all, Mr. Chairman, there are no 

extensive examples of international databases. I mean, here in the 

United Kingdom, we have a database which deals particularly with 

clinical trials, and the use of clinical trials. And in fact, the World 

Health Organization [WHO] also has a voluntary database on clinical trials. So, that is an example. 

And the National Center for Biotechnology, or GenBank, which 

is, of course, held in the United States, has an excellent international global database for looking particularly at gene therapies 

and the like. 

So, I think there are examples there. But really, it is hugely important that in terms of actually creating a database, that that is 

done in terms of international collaboration, that we include particularly Third World countries as well in that, because they are 

the most affected by climate changes, as we know. 

So, I think it is important to, first of all, find somewhere where, 

in fact, we would have the repository, and there would have to be 

international agreement on that. I think secondly, we would want 

to know what would go in the database. And we felt that there 

were a number of things, first of all, in terms of simply listing current research. 

I think it is quite possible, indeed, to pull together the research 

that is going on around the world. As you know, Mr. Chairman, 

there is some extensive research going on in the United States. 

There is research going on in Australia, in Canada, and elsewhere 

in the world. 

I think secondly, we need to ensure that we state that research 

is out. If we are looking at particularly modeling from, for instance, 

aerosols in stratosphere, it is important that we get the results of 

that midterm. We don’t wait for it to be completed. 

I think thirdly, that we make sure that the database looks at the 

aims of research, that when research projects are being launched, 

that it is clear what the aims are, so that other scientists around 

the world can, in fact, collaborate and work with that, can actually 

replicate its experiments. 

And I think fourthly, it is important that wherever research is 

taking place, that within the database comes the order of risk. 

That we know that a lot of these technologies are usually low risk 

and therefore, you know, can easily be lodged in a database without, in fact, having to have huge explorations or it causing controversy. 

Where, in fact, you are, for instance, seeding the oceans, if in 

fact, you are going to put aerosols into the stratosphere, which 

might have an effect somewhere else, then clearly, those elements 

of risk have got to be assessed and put into the database. All that 

would be hugely influential in actually guiding future 

geoengineering regulation. 

THE FUTURE OF GEOENGINEERING RESEARCH IN THE U.K. 

Chairman GORDON. Thank you, and how do you foresee the future of geoengineering research in the United Kingdom? What direction will it go, if at all? Are national or European Commission 
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geoengineering research programs likely to be a reality? Is the 

United Kingdom’s Defense Department looking at geoengineering 

possibilities also? 

Chairman WILLIS. Well, thank you, Mr. Chairman. I think what 

is interesting here is, if you would have asked me that question 18 

months ago, I would have said no, no, no, and no to all those 

points, because I think 18 months to two years ago, geoengineering 

was not on the agenda. 

I can recall having a Committee session in the U.K. Parliament 

with the Minister responsible for climate change, to ask if, in fact, 

there was any research being commissioned in this particular area, 

and the answer was no. We have Plan A, which is about mitigation, and we don’t, in fact, plan to go down the road of 

geoengineering. 

Eighteen months later, the government has commissioned research, to its credit. And in fact, the National Environment Research Council [NERC] is also conducting research. A number of 

leading universities in the U.K. are conducting research in terms 

of regulation, and as I have said to you, the Royal Society has conducted a major inquiry looking at the different types of 

geoengineering, and in fact, they have just announced that they are 

going to set up a major inquiry looking at the regulation of 

geoengineering. 

In Europe as well, while there is nothing in the current framework program in terms of research projects for geoengineering, we 

understand that the European Research Council is, in fact, considering bids to actually look at, particularly, the modeling of 

geoengineering in terms of certain aspects. 

So, this is on the rise, and I think it is good that that is happening, and it is good that we are not turning our minds away from 

the future need which might arise to use geoengineering technologies. 

And I agree totally with you, Mr. Chairman, that this is an issue 

of last resort and must not, in fact, deflect us from our major task 

of making sure that we put less CO2 into the air, and where it is 

there, that we look, in fact, to sequestrate it. 

ADDITIONAL OPPORTUNITIES FOR INTERNATIONAL

COLLABORATION

Chairman GORDON. And one last question. As we have discussed 

before, when you look at the major problems facing our world and 

globe, whether it is climate change, whether it is energy sustainability, or energy independence, or just sustainability of the planet, 

I think we are going to need cooperation with multinational efforts, 

both intellectually and financially. 

And I wanted to get your thoughts, again, in the future, what additional topics might be taken up? I know you had talked about 

synthetic biology at one time. Any other suggestions on those type 

of global issues that we might work on in the future? 

Chairman WILLIS. Well, Mr. Chairman, I think there is no doubt 

that the great challenges are not challenges simply for the United 

States or the United Kingdom, or indeed, for China or India, the 

emerging economies. 
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They are global challenges. The great challenges of water security, food security, energy, as well, of course, as issues like terrorism and other matters, all of which science has a major role to 

play, require global solutions. 

And I think that there is a fairly exhaustive list. I mean, for instance, the whole of the oceans. I can remember being in the 

United States not long ago, at Woods Hole Laboratory, you know, 

looking at the effect of the oceans on the climate. I think that that 

is an area for international and global cooperation. 

The issue of space, and the use of space, again, requires global 

activities. You and I talked, when you were last in London, about 

the whole issue of nanotechnologies, the way in which 

nanotechnologies are going to need very, very careful global cooperation if, in fact, we are going to make the most use of those 

technologies. 

The issue of sustainable agriculture: there is no way, by 2050, we 

are going to be able to feed the world’s population, given current 

agrarian policies. And therefore, the need for international cooperation there is enormous. 

And if I may finally say, both your economy and our economy in 

the U.K. have suffered massively because of the economic downturn. And if there is one area where there is a need for far greater 

cooperation, certainly between our two nations, in terms of the social science of economics. My goodness, that is one area we ought 

to look at. 

Chairman GORDON. Thank you, Chairman. My time has expired. 

In the United States, we have Americans and we have Texas 

Americans, and now I recognize my Ranking Member and good 

friend from Texas, Mr. Hall. 

PUBLIC OPINION OF GEOENGINEERING

Mr. HALL. Now, being from Texas, we are happy to have international discussions from time to time, and about 10 or 15 years 

ago, we had a similar discussion on asteroids here, urging England, 

Germany, France, and others to come together to share the cost of 

tracing and tracking. 

And it didn’t work out, because I guess there was not enough 

there, but we learned during that time that an asteroid missed the 

Earth only about 15 minutes, I think in 1986 or ’88, so there is a 

lot to learn together. And I admire the Chairman for making a trip 

over there. His trip there spawned this historical meeting, where 

you come before us, Chairman Willis, to testify. I have enjoyed 

hearing your testimony. 

I will ask you just a question or so, as kind a question as I know 

how to ask. I don’t really—I am not terribly enthusiastic about 

this, but I am excited about your appearance here and the Chairman’s vision. 

As you may have noticed from our newspapers, public opinion on 

the concept of geoengineering here in the United States covers the 

whole spectrum. It just goes everywhere here. Did you find yourself 

in a similar situation in England initially? 

Chairman WILLIS. Well, Representative Hall, welcome to you and 

it is good to talk to you. Or is it Mr. Hall I should officially address 

you as? But there is no doubt that when we did, and we did, I said, 
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a piece of investigation about geoengineering 18 months ago, as 

part of a bigger inquiry, that there were many people, and particularly some of the green NGOs, nongovernment organizations, who 

contacted us to say that this was really a distraction. It was distracting us from the main issue, which was about climate change, 

which was about removing CO2, and which was about stopping the 

temperature of the Earth rising. 

And it is interesting that that has slightly changed, and there is 

now an acceptance that this is a long-term technology, something 

which clearly needs to be put into the basket of tricks. But equally, 

it is important that it does not, in fact, actually take U.K. pounds, 

in your case, U.S. dollars, away from the main thrust, which is 

about creating sort of green technologies for transport, you know, 

for energy, and indeed, making sure that we don’t continue to create the problem. 

But I can tell you, Mr. Hall, that there are a significant number 

of people in the United Kingdom who actually regard this as a 

rather strange set of technologies, and ones that, quite frankly, we 

have better things to spend our time on. 

THE U.K. INQUIRY PROCESS

Mr. HALL. Did you start with public hearings? How did you initiate it? Did you start with public hearings to discuss the issue? 

Chairman WILLIS. Well, we—what we do with all our inquiries 

is, we announce a set of terms of reference for our inquiry, and of 

course, we engage the public immediately at that time. 

We then try to seek out witnesses, as you did, including Professor Shepherd, from across the globe, in order to be able to feed 

into us, into our inquiry. And then to assemble a report, and make 

a number of key recommendations, including of course, interviewing the government, the government ministers, to see what 

government policy is. 

And of course, we did not have any government policy in this 

particular area, because government did not have a policy towards 

geoengineering, and it is interesting that whilst they still don’t 

have a major commitment to geoengineering as a mitigation technology, nevertheless, the governments have, I think to their credit, 

actually engaged with the science, and to at least examine whether 

the science is or could be could be effective and predictable. 

Mr. HALL. I thank you for that, and I am near the end of my inquiry. Appreciate you being here. It is historic. I know his trip over 

there, visiting with you, spawned this meeting, and I think it is 

very helpful. Perhaps we can reciprocate with you somewhere down 

the line. 

Thank you, sir, and I yield back my time. 

Chairman GORDON. Ms. Fudge is recognized. Or Governor 

Garamendi is recognized for five minutes. 

Mr. GARAMENDI. The inquiry—the information from the United 

Kingdom is excellent, and I don’t have any questions right now. 

Thank you. 

Chairman GORDON. And I see Ms. Dahlkemper, and Ms. 

Dahlkemper is recognized. 

Ms. DAHLKEMPER. I thank you, Mr. Chairman. This is a very interesting hearing, and I certainly appreciate the Chairman being 
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here with us today, but I also do not have any questions at this 

time. 

I am sure, as we go forward with this cooperation, we will have 

many more questions. So, thank you, and I yield back. 

Chairman GORDON. Well, Chairman Willis, as I said earlier, we 

are on the precipice of votes here. We received your report last 

night. We have been in constant contact with your staff, and been 

very pleased with that. 

We are going to digest that now, and hopefully, we will have a 

chance to be back in touch with you, but we want to thank you for 

the excellent body of work that you have presented us with. 

Chairman WILLIS. Thank you indeed, Mr. Gordon, and it has 

been a pleasure not only to present to your committee, but on the 

two opportunities we have been able to meet over the past year, 

you have treated us with huge courtesy, and we hope that this will 

be the sign of things to come, certainly after our general election 

here in May. 

Chairman GORDON. Thank you. And we are going to move to a 

second panel, of which we are going to keep you tuned in, and so, 

if you would like to continue to hear that, you are welcome, until, 

again, we are required to leave for votes. 

And so, I would ask the second panel to come forward. We are 

now told that it is going to be about 1:00 before the votes get started, so—okay. 

So, we are ready now for our second panel. It is my pleasure to 

introduce our witnesses. First, Dr. Frank Rusco is the Director of 

Natural Resources and Environment at the Government Accountability Office, GAO. 

Dr. Scott Barrett is the Lenfest Professor of Natural Resource 

Economics at the School of International and Public Affairs and the 

Earth Institute at Columbia University. 

Dr. Jane Long is the Deputy Principal Associate Director at 

Large at Lawrence Livermore National Lab [LLNL]. 

And Dr. Granger Morgan is Professor and Head of the Department of Engineering and Public Policy, as well as the Lord Chair 

Professor in the Engineering at the Carnegie Mellon University. 

As witnesses should know, you have five minutes for your spoken 

testimony. Your written testimony has been included in the record, 

and when you complete your spoken testimony, we will then have 

questions. Each member will have five minutes to ask those questions. 

So, Dr. Rusco, we will begin with you. 

STATEMENTS OF DR. FRANK RUSCO, DIRECTOR OF NATURAL 

RESOURCES AND ENVIRONMENT, GOVERNMENT ACCOUNTABILITY OFFICE 

Dr. RUSCO. Chairman Gordon, Ranking Member Hall, and Members of the Committee, thank you for the opportunity to speak before you today on the important issue of domestic and international 

governance of geoengineering. 

Geoengineering has recently become an area of intensified interest, in part, because of challenges in reaching international agreement to limit the growth of, and eventually reduce, global greenhouse gas emissions. 
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In this context, if severe or relatively sudden climate change occurs at some future date, attempts to reverse or slow such trends 

through deployment of geoengineering technologies, either by reflecting some of the sun’s rays that help heat the Earth, or by removing and sequestering ambient carbon dioxide, may become relatively more attractive, especially in nations or regions that are 

particularly vulnerable to the effects of climate change. 

Three facts point to the importance of getting in front of the 

issue of domestic and international governance of geoengineering 

research and deployment. First, the severity of the effects of large 

scale geoengineering, efforts are uncertain, and would likely be distributed unevenly, potentially creating relative winners and losers. 

As a result of the unknown severity and potential unevenness of 

outcomes, geoengineering research or deployment at a scale large 

enough to actually influence the global climate would carry with it 

the potential to be economically and politically destabilizing. 

Second, climate change modeling exercises or small scale physical experiments for certain geoengineering approaches, such as 

stratospheric aerosol injection, may be inadequate to evaluate the 

efficacy or extent and distribution of unintended effects of 

geoengineering deployed if at full scale. Put simply, to adequately 

assess the efficacy and distribution of effects of geoengineering, it 

may be necessary to actually deploy these technologies on a large 

scale and for a long period of time. 

Research on this scale would, itself, have uncertain and likely 

uneven effects around the globe, would potentially create winners 

and losers, and could lead to conflict over how to mitigate or adapt 

to any adverse effects. 

Third, some geoengineering technologies could be implemented at 

low enough cost that they could be undertaken by nations or other 

actors unilaterally, or in coalitions. Simply put, if a nation or group 

perceives it in their interest to deploy such a technology that will 

have global but uncertain and unevenly distributed effects, it may 

well be possible for them to do so without broad international consensus or assistance. 

In our ongoing work in this area, we have found that some federal agencies have funded research and small demonstration 

projects of technology related to geoengineering. However, federal 

agencies have not been directed to, nor does there exist, a coordinated federal geoengineering research strategy. 

Further, some existing federal laws could apply to 

geoengineering research and deployment. However, some federal 

agencies have not yet assessed their authority to regulate 

geoengineering, and those agencies that have done so have identified regulatory gaps. 

For example, under the Marine Protection, Research, and Sanctuaries Act of 1972, certain persons would be prohibited from 

dumping material for ocean fertilization into the ocean without a 

permit from EPA. EPA officials told us that the ocean dumping 

permitting process is sufficient to regulate certain ocean fertilization activities. However, they noted a domestic company could conduct ocean fertilization outside of EPA’s regulatory jurisdiction if, 

for example, the company’s fertilization activities took place outside 
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U.S. territorial waters from a foreign registered ship that embarked from a foreign port. 

With regard to international governance, legal experts we spoke 

with identified a number of existing international agreements that 

are potentially relevant to specific geoengineering technologies. 

However, these agreements were not drafted with geoengineering 

in mind, and the signatories and parties to these agreements have 

typically not determined whether and how they apply to 

geoengineering. 

Further, these agreements have generally not been signed by all 

countries, nor have all signatories ratified or acceded to the agreements, thereby giving them the force of law. 

While GAO cannot advise Congress at this time on specific needs 

for domestic or international governance of geoengineering research 

or deployment, we found broad consensus among both legal and scientific experts we spoke with that any geoengineering research of 

a large enough scale to have trans-boundary effects should be addressed in a transparent and international manner. 

However, there was a variety of views on the precise structure 

of such regulation or governance. For example, scientific experts 

recommended that research governance be established in consultation with the scientific community, in order to not unduly restrict 

research. 

Similarly, we found a broad consensus that additional 

geoengineering research is warranted, but no consensus on the desirable extent of such research. We look forward to continuing our 

work in this area for the Committee, and hope to be able to make 

specific recommendations for Federal actions in future reports. 

Mr. Chairman, this concludes my statement. I would be happy 

to answer any questions you or the Committee may have. 

[The prepared statement of Dr. Rusco follows:]
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PREPARED STATEMENT OF FRANK RUSCO
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BIOGRAPHY FOR FRANK RUSCO

Frank Rusco is a Director in GAO’s Natural Resources and Environment team, 

working on a broad spectrum of energy and related issues. He has worked at GAO 

for almost 11 years, at first, working as an economist in the Center for Economics. 

In addition to providing economics analysis, he also managed numerous teams 

working on energy topics, including electricity restructuring, and crude oil and petroleum products markets, as well as related natural resources work on oil and gas 

royalty collection and policy. Prior to coming to GAO, he was an assistant professor 

in the Department of Economics for the University of Hong Kong. He has published 

articles on energy, transportation, environmental economics and related topics. He 

received both his M.A. and Ph.D. in economics from the University of Washington 

in Seattle and his B.A. degree in music performance from the University of Nevada, 

Reno.

Chairman GORDON. Thank you, Dr. Rusco, and Dr. Morgan is 

recognized. 
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STATEMENTS OF DR. GRANGER MORGAN, PROFESSOR AND 

DEPARTMENT HEAD, DEPARTMENT OF ENGINEERING AND 

PUBLIC POLICY, AND LORD CHAIR PROFESSOR IN ENGINEERING, CARNEGIE MELLON UNIVERSITY 

Dr. MORGAN. Mr. Chairman and distinguished Members, thank 

you for the opportunity to appear today to discuss issues related to 

research and governance in geoengineering. 

I am Granger Morgan, head of the Department of Engineering 

and Public Policy at Carnegie Mellon University. Our department 

is the home of a large National Science Foundation-supported distributed center on climate decision research. 

Some of our center’s research has addressed the subject of solar 

radiation management, or SRM, that would involve adding fine reflective particles to the stratosphere. We have also supported research on technology for directly scrubbing carbon dioxide out of 

the atmosphere. 

As part of our work on SRM, we have organized and run two 

workshops to engage leading climate scientists and foreign policy 

experts in discussions of the issues of global governance of SRM, 

and we have published a paper on this topic in the Journal of Foreign Affairs that I have appended to my written testimony. 

I want to emphasize that I am not arguing that the U.S. or anybody else should engage in SRM. The U.S. and other large emitting 

countries need to get much more serious about reducing emissions 

and lowering the concentration of atmospheric carbon dioxide. I believe that can be done at an affordable cost. 

However, we also need to understand, to undertake a serious 

program of research on SRM. In a piece attached to my written testimony, my colleagues and I argued, in Nature this January, that 

the risk of not understanding whether and how well SRM might 

work, what it would cost, and what its intended and unintended 

consequences might be, are today greater than the risks associated 

with undertaking such research. 

Initial research on SRM should be supported via the National 

Science Foundation at a level of a few million dollars per year. NSF 

should be the initial funding agency for two reasons. One, NSF 

does a good job of supporting open, investigator-initiated research, 

and we need a lot of bright people thinking about this topic from 

different perspectives before developing any serious program or 

field studies. 

Two, in additional to natural science and engineering, NSF supports research in the social and behavioral sciences, and those perspectives on the subject are urgently needed. However, we will not 

be able to learn everything we need to learn with laboratory and 

computer studies, and once it is clear what sorts of field studies are 

needed, then NASA and/or NOAA should become involved. I believe 

that DOE should stay focused on the problems of de-carbonizing 

the energy system and reducing atmospheric concentrations of carbon dioxide. 

All research on SRM should be open and transparent. Hence, 

SRM research should not be undertaken by DoD or the intelligence 

communities. Private, for-profit funding of SRM research should be 

actively discouraged, since it holds the potential to create a special 

interest that might push to move beyond research into deployment. 
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I turn now to the global governance of SRM research. I believe 

that there should be constraints on modest, low level field studies, 

done in an open and transparent manner, designed to better understand what is and what is not possible, what it might cost, and 

what possible unintended consequences might result. 

That said, I think it likely that pressure will grow for some more 

formal international oversight of SRM, and for that reason, I think 

one of the first objectives in a U.S. research program should be to 

give the phrase ‘‘modest low-level field testing’’ a more precise definition. 

[The information follows:]

My first slide shows one way to frame this issue. In that diagram, X, Y, and Z define the limits of an allowed zone. They refer, 

respectively, to the upper bounds on the amount of radiative forcing that an experiment might impose, the duration of that forcing, 

and the possible impacts on ozone depletion. 

[The information follows:]
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As my second slide shows, early research should ask what should 

the allowed zone, how should the allowed zone be defined, and 

should it use different axes? What should be the shape of that 

zone? What should be the values of X, Y, Z, and so on, and then, 

in joint discussion with foreign policy experts, what forms of international agreement and enforcement, if any, would be most appropriate, and what scientific input would they require? 

Now, all my remarks are focused on SRM. There are a number 

of technologies for directly scrubbing carbon dioxide from the 

Earth’s atmosphere and sequestering it underground. These are 

very important. The Department of Energy should support research 

and development, and test such technologies, starting at a level of 

several tens of millions of dollars per year. Research and development by private, for-profit firms in this area should be very actively encouraged. 

Mr. Chairman, thank you. 

[The prepared statement of Dr. Morgan follows:]

PREPARED STATEMENT OF GRANGER MORGAN

Mr. Chairman, distinguished members, thank you for the opportunity to appear 

today to discuss research and governance related to the issue of geoengineering. 

I am Granger Morgan, Professor and Head of the Department of Engineering and 

Public Policy at Carnegie Mellon University. I hold a Ph.D. in applied physics and 

have worked on a range of the technical and policy aspects of climate change for 

roughly 30 years. 

When we were awarded a large NSF grant to create The Center for Integrated 

Study of the Human Dimensions of Global Change, in 1995, one of the early things 

we did was to conduct a review of the state of knowledge in geoengineering. My colleagues Hadi Dowlatabadi and David Keith published several papers as a result, including:
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• David W. Keith, ‘‘Geoengineering the Climate: History and Prospect,’’ Annual 

Review of Energy and the Environment, 25, pp. 245–284, 2000.

• David W. Keith and Hadi Dowlatabadi, ‘‘A Serious Look at Geoengineering, 

Eos, Transactions American Geophysical Union, 73, pp. 289–293, 1992.

After this initial work we moved on to other topics, and I did not think seriously 

about geoengineering again until about three years ago. At that time the foreign 

policy community was largely unaware of the possibility that humans might be able 

to rapidly increase earth’s albedo (the fraction of sunlight reflected back into space) 

by roughly one percent and in so doing offset the warming caused by carbon dioxide 

and other greenhouse gases. The Royal Society had recently termed such activity 

SRM, or ‘‘solar radiation management.’’

In reflecting on the dismayingly slow pace of progress the world was making in 

cutting emissions of carbon dioxide, I began to be concerned that there is a growing 

risk that large effects from climate change might occur somewhere in the world that 

could induce a nation or group of nations to unilaterally modify the albedo of the 

planet in order to offset rising temperature. If someone were to do that, it could impose large effects on the entire planet. 

In order to start a conversation with the foreign policy community I enlisted four 

colleagues (two like me with backgrounds in physics and planetary science backgrounds and two with backgrounds in political science and foreign policy). We organized a workshop at the Council on Foreign Relations (CFR) here in Washington, 

DC on May 5, 2008. We had excellent attendance from senior folks in both the 

science and foreign policy communities. 

The five of us subsequently published a paper in the journal Foreign Affairs that 

summarized our thinking at that time:

• David G. Victor, M. Granger Morgan, Jay Apt, John Steinbruner, and Katharine Ricke, ‘‘The Geoengineering Option,’’ Foreign Affairs, 88(2), 64–76, 

March/April 2009. (Attachment 2)

Because the CFR workshop involved only North Americans, and because this is 

a global issue, I subsequently organized a second more international workshop, 

again with the objective of stimulating discussion between the scientific and foreign 

policy communities. This second workshop was hosted by the Government of Portugal on April 20–21, 2009. Participants in this second workshop came from North 

America, from across the E.U., and from China, India and Russia. 

SRM has five key attributes:

1. It is fast (i.e. cooling could be initiated in months not decades).

2. It is likely to be relatively inexpensive (i.e. as much as 100 to 1000 times 

cheaper than achieving the same temperature reduction through a systematic reduction of global emissions of carbon dioxide).

3. It will be imperfect (i.e. it will do nothing to offset the effects of rising 

carbon dioxide levels on ocean acidification and the associated destruction of coral reefs and ocean ecosystems; it will dry. out the hydrological 

cycle—and while recent studies indicate it will move temperature and 

precipitation back closer to what they were before climate change, it will 

not do so perfectly and there will be differences in how well it will work 

in different parts of the world); it will not offset impacts from elevated 

concentrations of carbon dioxide on terrestrial ecosystems.

4. Once started, if SRM is ever stopped, and carbon dioxide emissions have 

continued to rise, the resulting rapid increase in temperature would result in catastrophic ecological effects.

5. Unlike emission reduction which requires cooperation by all large 

emitters, a single nation (indeed, perhaps even a single very wealthy private party) could undertake SRM and effect the entire planet.

Up until now there has been very little serious research conducted on strategies 

to modify rapidly the albedo of the planet (i.e. on SRM): Historically, most folks in 

the climate science community have been reluctant to work in this area for two reasons:

• they did not want to deflect scarce funding and attention from the very important task of improving our understanding of the climate system;

• they were worried that if we better understand SRM and how to do it, that 

might deflect attention away from reducing emissions, and might also increase the probability that someone would actually engage in SRM.
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I want to emphasize in the strongest possible terms that I am not arguing that 

the U.S. or anyone else should engage in SRM. We need to get much more serious 

about achieving a dramatic reduction in emissions of carbon dioxide. 

However, because I believe that we are getting closer to the time when someone 

might be tempted to unilaterally engage in SRM in order to address local or regional 

problems caused by climate change, or a situation in which the world faces a sudden 

and unexpected climate emergency that places large number of people at risk, I 

think we have passed a tipping point. In my view, the risks of not understanding 

better whether and how SRM might work, what its intended and unintended consequences might be, and what it might cost, are today greater than the risks associated with doing such research. My colleagues and I have spelled out these arguments in two recent publications:

• David W. Keith, Edward Parson and M. Granger Morgan, ‘‘Research on Global Sun Block Needed Now,’’ Nature, 463(28), 426–427, January 2010. (Attachment 3)

• M. Granger Morgan, ‘‘Why Geoengineering?,’’ Technology Review, 14–15, January/February 2010.

With this background, I turn now to two questions which I understand this Committee is especially interested: who should fund research and what approach should 

be taken to issues of governance. 

Up until now my remarks have been exclusively about SRM. There are a number 

of technologies for directly scrubbing carbon dioxide the earth’s atmosphere and sequestering it deep underground. In my view, these are very important, and deserve 

considerably expanded research support, but do not pose significant issues of global 

governance. While slow, this approach is particularly attractive because it gets to 

the root of the problem by reducing the amount of carbon dioxide in the atmosphere. 

Thus, unlike SRM it also addresses ecosystem risks such as ocean acidification. 

I believe that the Department of Energy should support research to develop and 

test technology to directly scrub carbon dioxide from the atmosphere at a level starting at several tens of millions of dollars per year. I do not believe that more than 

modest support is warranted for other strategies to remove carbon dioxide from the 

atmosphere. 

As with power plants with carbon capture (CCS), once carbon dioxide has been 

captured it must be disposed of. At the moment, the best alternative is to do this 

via deep geologic sequestration. There are significant regulatory challenges for such 

sequestration. At Carnegie Mellon, we anchor the CCSReg project that is developing 

recommendations on the form that such regulation should take. Details are available on the web at www.CCSReg.org and are summarized in Attachment 4. 

With respect to SRM, I believe that initial research support should be provided 

via NSF beginning at a level of a few million dollars per year. Indeed, both the policy and scientific work that I and my colleagues and Ph.D. student (Katharine 

Rieke) have been doing in this area have been conducted with support from NSF. 

I argue that NSF should be the initial funding agency for two reasons:

1. NSF does a good job of supporting open investigator initiated research and 

we need a lot of bright people thinking about this topic from different perspectives in an open and transparent way before we get very far down the 

road of developing any serious programs of field research.

2. In addition to natural science and engineering, NSF supports research in the 

social and behavioral sciences. Perspectives and research strategies from 

those fields needs to be brought to bear on SRM as soon as possible.

We will not be able to learn everything we need to learn with laboratory and computer studies. Once it becomes clear that we need to be doing some larger scale field 

studies, then it would be appropriate to engage NASA and or NOAA. In addition 

to small scale field studies, it may also be possible to learn through more intensive 

studies of the ‘‘natural SRM experiments’’ that occur from time-to-time when volcanoes inject large amounts into the stratosphere. NSF, NASA or NOAA would all be 

able to prepare instrumentation and research plans to study such events, and 

should be encouraged to do so. 

I would argue against involving DoE. They need to stay focused on the problems 

of decarbonizing the energy system. 

While private funding should be encouraged for research and development of technologies to scrub carbon dioxide out of the atmosphere, steps should be taken to 

strongly discourage private funding for SRM since that holds the potential to create 

a special interest that might push to move past research to active deployment. 
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I believe that any research in SRM should be open and transparent. For this reason, and for reasons of international perceptions, 1 argue strongly that research on 

SRM should not be undertaken by DOD or by the intelligence communities. 

Finally, I turn to the issue of global governance and SRM—the subject of the two 

workshops I described above. People do lots of things in the stratosphere today, 

most of which are pretty benign. So long as it is public, transparent, and modest 

in scale, and informally coordinated within the scientific community (e.g. by a group 

of leading national academies, the international council of scientific unions (ICSU), 

or some similar group) I believe there should be no constraints on modest low-level 

field testing, done in an open and transparent manner, designed to better understand what is and is not possible, what it might cost, and what possible unintended 

consequences might result. 

That said, I think it likely that pressure will grow for some more formal international oversight. For that reason I think one of the first objectives in a U.S. research program should be to give the phrase ‘‘modest low-level field testing’’ a more 

precise definition. Figure 1 illustrates one way to think about this issue. In this diagram X, Y and Z define the limits to an ‘‘allowed zone.’’ They refer respectively to 

upper bounds on the amount of radiative forcing that an experiment could impose, 

the duration of that forcing, and the possible impact on ozone depletion (the surface 

of particles can provide reaction sites at which ozone destruction could occur). 

Initial research should explore whether these three axis are the right ones, or 

whether there should be other or additional dimensions.

The ‘‘allowed space’’ might not be a simple cube. For example, as Figure 2 suggests, if the scientific community thought it was important to test a small number 

of particles that because of special properties would be very long lived, but would 

have de minimus effect on planetary forcing or ozone depletion, a more complex ‘‘allowed space’’ might be called for.
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I am not prepared to argue that there should be a formal treaty any time soon 

that addresses these issues. However, I think there is a good chance that pressure 

will grow for some form of international agreement (perhaps just an agreement 

among major states that others can choose to sign on to). For this reason we should 

start now to lay the scientific foundation for defining such an ‘‘allowed space.’’ If 

work has not been done before hand it might be very hard to introduce a reasoned 

scientific argument if political momentum grows for serious limitations—perhaps 

even an outright ban or ‘‘taboo.’’ For this reason I think we should continue to promote discussion between the scientific and foreign policy communities about what 

form(s) of international agreement and enforcement (if any) would be most appropriate and what sorts of scientific foundation they would require.

Attachments: 

1. Short vita for M. Granger Morgan. 

2. Copy of the paper ‘‘The Geoengineering Option’’ from Foreign Affairs, 2009. 

3. Copy of the opinion piece ‘‘Research on Global Sun Block Needed Now’’ from 

Nature, 2010. 

4. Summary of regulatory recommendations for deep geological sequestration of 

carbon dioxide from the CCSReg project.
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BIOGRAPHY FOR GRANGER MORGAN

M. Granger Morgan is Professor and Head of the Department of Engineering 

and Public Policy at Carnegie Mellon University where he is also University and 

Lord Chair Professor in Engineering. In addition, he holds academic appointments 

in the Department of Electrical and Computer Engineering and in the H. John 

Heinz III College. His research addresses problems in science, technology and public 

policy with a particular focus on energy, environmental systems, climate change and 

risk analysis. Much of his work has involved the development and demonstration 

of methods to characterize and treat uncertainty in quantitative policy analysis. At 

Carnegie Mellon, Morgan directs the NSF Climate Decision Making Center and codirects, with Lester Lave, the Carnegie Mellon Electricity Industry Center. Morgan 
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serves as Chair of the Scientific and Technical Council for the International Risk 

Governance Council. In the recent past, he served as Chair of the Science Advisory 

Board of the U.S. Environmental Protection Agency and as Chair of the Advisory 

Council of the Electric Power Research Institute. He is a Member of the National 

Academy of Sciences, and a Fellow of the AAAS, the IEEE, and the Society for Risk 

Analysis. He holds a BA from Harvard College (1963) where he concentrated in 

Physics, an MS in Astronomy and Space Science from Cornell (1965) and a Ph.D. 

from the Department of Applied Physics and Information Sciences at the University 

of California at San Diego (1969).

Chairman GORDON. Thank you. And Dr. Long is recognized. And 

we need to use your—there you go. 

STATEMENTS OF DR. JANE LONG, DEPUTY PRINCIPAL ASSOCIATE DIRECTOR AT LARGE AND FELLOW, CENTER FOR 

GLOBAL STRATEGIC RESEARCH, LAWRENCE LIVERMORE 

NATIONAL LAB 

Dr. LONG. Thank you. Okay, I hope the timer starts now. Mr. 

Chairman and Members of the Committee, thank you for this opportunity to talk to you. 

My name is Jane Long. I am Principal Associate Director at 

Large at Lawrence Livermore, and I am currently acting as the CoChair of the National Commission on Energy Policies Task Force 

on Geoengineering. Today, my comments represent my own views, 

and not the views of either my laboratory or the NCEP Task Force, 

which has just begun its work. 

I am going to talk about geoengineering, about three classes of 

geoengineering that were identified by the American Meteorological 

Society: climate remediation, or taking carbon dioxide out of the 

air; climate intervention, which is an actual act to change the nature of the climate; and the third category, which is a catch-all category. Most of my remarks will focus on the second category, because you are interested in governance, and this is where the governance issues largely occur. 

My only remark about the category of climate remediation in my 

oral remarks today would be that there are fewer governance 

issues associated with it, that the research, as Dr. Morgan has 

pointed out, falls closely allied to CCS, carbon capture and storage 

research currently being pursued by the Department of Energy, 

and that this program should be expanded to include this. From a 

governance perspective, there is a question about whether the technology should be a public good, or we should tap into the forces of 

the market, and I think that that question depends on whether we 

end up having a price for carbon. If we have a price for carbon, this 

technology could easily be innovated in the private sector. If not, 

it is more like picking up the garbage, and should be a public good. 

Let me turn my attention now to climate intervention. I really 

endorse the U.K. principles that were heard this morning. I think 

they are extremely important, and I would like to endorse those, 

and say that those are at the top of my list. 

First of all, I think that the climate technology should be a public 

good, and we should say, up front, that we are not planning for deployment. If we start our research program by saying we are planning for deployment, we will feel a lot of pressure and a lot of 

pushback on whether people are against it. A lot of people who are 
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against the idea of geoengineering are clearly for research, and we 

should not involve those at this point. 

There are four questions that we need to get after in the national 

research governance format. One is what constitutes an appropriate level of governance for specific types of research? The second 

is, what are the guiding principles that should be used to sanction 

the research? And then, given these principles, what process should 

be used to sanction the research? And then, how will the governance process engage society? 

Dr. Morgan has presented a concept for determining that level 

of research which should proceed with what I will call only ‘‘normal 

governance’’. I endorse that, and recommend that you convene a 

National Academy of Science panel now to help define what that 

bright line is, below which research can proceed with impunity. 

This is critically important, because we need to get started on research, and a lot of research is not problematic, and getting a definition of what we can go ahead with would be very important. 

Then, we need to work on principles. I would like to add a few 

principles to those you heard this morning, and that is: beneficence 

should be a principle. We should have, we heard transparency, we 

heard public good, we heard public participation, we heard independent assessment of impacts, and we heard governance before 

deployment. 

But I would like to add to that, we need to have some assessment that the benefits of the project, the potential benefits of the 

project, clearly outweigh any risks that are there. And some aspect 

of justice, ensuring a reasonable, non-exploitive, well considered 

procedures, and that the risks are fairly distributed. 

In the research program, I think that the justice perspective is 

one that should be quite clear. We should not be taking advantage 

of people or peoples in doing research, but beginning to ask the 

question in the research program that will help us as we move towards possible deployment. 

The review process then has to go forward, and let me just make 

one clear point about that. We don’t know how to govern this research and do the review, but we have other models, and what I 

would recommend now is that we start a program with mock governance and mock review boards, that can try different principles 

and different procedures and see how they work, much as the institutional reviews for human subjects research try different ways to 

proceed, and then assess how well they have done. 

Thank you for the opportunity to comment today, and I will, the 

rest of my remarks are my written testimony. Thank you. 

[The prepared statement of Dr. Long follows:]

PREPARED STATEMENT OF JANE LONG

Mr. Chairman, members of the committee, thank you for this opportunity to add 

my comments about geoengineering to the record. This is a difficult and complex 

topic and your willingness to organize these sessions is both courageous and admirable. I hope I can add a little to the dialogue. 

My academic background is geohydrology; I have worked in environmental and resource problems for over 35 years. My experience includes nuclear waste storage, 

geothermal energy, oil and gas reservoirs, environmental remediation, sustainable 

mining, climate science, energy efficiency, energy systems and policy, adaptation 

and recent attention to geoengineering. I have worked at two national laboratories, 

Lawrence Berkeley National Lab and Lawrence Livermore National Lab and have 
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been a dean of engineering and science at University of Nevada, Reno. I am a Senior Fellow of the California Council on Science and Technology (CCST) and an Associate of the National Academy of Sciences. In my current position, I am a fellow in 

Lawrence Livermore National Laboratory’s Center for Global Strategic Research 

and Associate Director at Large for the laboratory. I work in developing strategies 

for a new, climate friendly energy system and currently chair the CCST’s California’s Energy Future committee which is charged with examining how California 

could meet 80% reductions in greenhouse gas emissions by 2050. I am also a member of the State of California’s Climate Change Adaptation Advisory Council. I currently serve as co-chair of the National Commission on Energy Policy’s (NCEP) Task 

Force on Geoengineering. I work to understand and advance a full spectrum of management choices in the face of climate change: mitigation, adaption and now 

geoengineering. 

My comments today reflect the perspective of my experience. They are my own 

opinions and do not reflect positions taken by my laboratory (Lawrence Livermore 

National Laboratory) or the NCEP task force on geoengineering I co-chair.

Introduction 

Our climate is changing in response to massive emission of greenhouse gases. 

First, we have to stop causing this problem. We have to change our energy system, 

food system, transportation system, industries and land use patterns. Even with 

mandatory concerted effort, such massive change will take decades. During these 

same decades we will continue to burn fossil fuels and add to the greenhouse gases 

we have already emitted. This atmospheric perturbation will last for centuries and 

will continue to warm our planet. We have created, and will continue to create unavoidable risk of disruptions to our way of life which may force us to spend more 

on protection (resistance), change our way of life to accommodate the change (resilience), or perhaps even to abandon parts of the Earth that are no longer habitable 

by virtue of being under water or having too little fresh water (retreat). 

Because the carbon dioxide we have already emitted will be with us for centuries, 

the problem of climate change cannot be ‘‘solved’’ in the same sense that other pollution problems—such as ozone depletion—have been solved by phasing out emissions 

over time. Climate change is like a chronic disease that must be managed with an 

arsenal of tools for many years while we struggle with a long term cure. In this future, if climate sensitivity (the magnitude of temperature change resulting from a 

doubling of CO2 concentrations in the atmosphere) turns out to be larger than we 

hope or mitigation proceeds too slowly, we cannot rule out the possibility that climate change will come upon us faster and harder than we—or the ecosystems we 

depend on—can manage. No one knows what will happen, but we face an uncertain 

future where catastrophic changes are within the realm of the possible. 

In the face of this existential threat, prudence dictates we try to create more options to help manage the problem and learn whether these are good options or bad 

options. I believe this is the most fundamental of ethical issues associated with our 

climate condition. We must continue to strive to correct the problem. This is why 

scientists today have become interested in a group of technologies commonly called 

geoengineering that are aimed at ameliorating the harmful effects of climate change 

directly and intentionally. Intentional modification of the climate carries risks and 

responsibilities that are entirely new to mankind. (We accept unintended but certain 

harm to climate from energy production much more easily that we accept unintended harm through intentional climate modification.) As we consider 

geoengineering, we have to recognize that society has not been able to quickly or 

easily respond to the climate change challenge. Consequently, the geoengineering 

option isn’t just a matter of developing new science and technologies. It is also a 

matter of developing new social and political capacities and skills. 

As much as I think we should research geoengineering possibilities, I think we 

should remain deeply concerned by the prospect of geoengineering. We will not be 

able to perfectly predict the consequences of geoengineering. Some effects may be 

irreversible and unequally distributed with harm to some even if there is benefit 

to many. Geoengineering could be a cause for conflict and a challenge for representative government. Geoengineering might be necessary in the future, but as we proceed to investigate this topic, we will need extremely good judgment and a very 

large dose of hubris. 

Three different classes of geoengineering have been identified (American Meteorological Society, http://www.ametsoc.org/POLICY/2009geoengineering

climate¥amsstatement.html). The first is actively removing greenhouse gases from 

the atmosphere. This has been called ‘‘Climate remediation’’ or carbon dioxide removal (CDR) or ‘‘carbon management’’. Climate remediation is similar in concept to 

cleaning up contamination in our water or soil. The first problem is to stop polluting 
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(mitigation) and the second is to remove the contaminants (remediation) and put 

them somewhere—for example filter CO2 out of the air and pump it underground. 

The second set of technologies has been called ‘‘Climate intervention’’ where we 

act to modify the energy balance of the atmosphere in order to restore the climate 

closer to a prior state. Climate intervention has also been called solar radiation 

management (SRM) or sun-block technology and some consider the technologies to 

be a radical form of adaptation. If we cannot find a way to live with the altered 

climate, we intervene to roll back the change. 

The third is a catch-all category that includes technologies to manage heat 

flows in the ocean or actions to prevent massive release of methane in the melting 

Arctic. These technologies are less well understood and developed, but the classification recognizes that not all the ideas are in and, as well, we may wish to address 

some very specific global or sub-global scale emergencies caused by climate change. 

I do not view any of these methods as stand-alone solutions, but some or all of 

these could be integrated in a comprehensive climate change strategy that starts 

with mitigation. A comprehensive climate change strategy might include:

• A steady, but aggressive transformation of the global energy system to eliminate emissions with concurrent elimination of air pollution in a few decades 

(mitigation) • Carbon removal over perhaps 50 to 100 years to return to the ‘‘safe zone’’ of 

greenhouse gas concentrations (climate remediation) 

• Time limited climate intervention to counteract prior emissions and reductions in air pollution, tapering off until greenhouse gases fall to a ‘‘safe’’ level 

(climate intervention). 

• Specific focused actions to reverse regional climate impacts such as preventing methane burps or melting Arctic ice (technologies from the ‘‘catch-all’’ 

category)

My remarks below do not discuss the technologies themselves in any depth as 

that has been done by others nor are they comprehensive. I will discuss some of 

the implications for research and experimentation. Where possible I will comment 

on existing US research programs and their capacity or suitability to expand into 

geoengineering research. As well, I will try to point to specific research topics that 

I have not seen in the geoengineering discourse up to now which are critical for any 

future geoengineering capability. I will bring out specific issues related to governance and international relations and some possible approaches for dealing with 

these. Discussion of governance and international relationships will focus mainly on 

climate intervention methods which are in general a more difficult societal and research problem. I will also some important research needed in climate science which 

is also critical for geoengineering.

Climate remediation technologies 

Climate remediation technologies are with some exceptions relatively safe and 

non controversial. They address the root cause of the problem, but these methods 

are slow to act. It would take years if not decades to reduce the concentration of 

CO2 in the atmosphere through air capture and sequestration. These technologies 

are expensive when compared to the option of not emitting CO2 in the first place. 

It costs less to capture concentrated streams of CO2 in flue gas or to use non-emitting sources of energy in lieu of burning fossil fuel, so many carbon removal technologies are likely to remain uneconomical until we have exhausted the opportunities for mitigation. However, research into these ideas is important because at some 

point we may decide that the atmospheric concentrations must be brought down 

below stabilized levels. If we don’t want to wait many hundreds of years for this 

to happen through natural processes, we may have to actively remove greenhouse 

gases. As we begin to understand more about the costs of adapting to unavoidable 

climate change, remediation technologies may become a cost effective option. Developing carbon removal technology that is reliable, safe, scalable and inexpensive 

should be the goal of a research program. 

Some of the more promising technologies in carbon removal are closely related to 

carbon capture and storage (CCS) technologies. CCS offers the most, if not only 

promise for preventing greenhouse gas emissions from fossil fuel-fired electricity 

generation. For CCS, we contemplate separating out CO2 after combustion of coal 

and then pumping it deep underground into abandoned oil or gas fields or saline 

aquifers. The technologies for removing CO2 from air (air capture) and flue gas are 

similar. 

In general, CCS is expected to be much less expensive than air capture, but air 

capture does have some possible advantages over CCS. It may be possible to site 

air capture facilities near a stranded source of energy (remote geothermal or wind 
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power for example, or in the middle of the ocean) and also near geologic formations 

that are capable of holding the separated gases. This arrangement might obviate 

some of the infrastructure costs associated with capturing CO2 at a power plant and 

having to choose between locating the power plant near the geologic storage reservoir and transmitting the power to the load, or conversely locating the power 

plant near load and conveying the CO2 to the storage facility. Further the cost of 

capture is likely to decline. In the long-run these considerations may become dominant. 

After capturing the CO2, it has to be put somewhere isolated from the atmosphere. Currently, we are considering geologic disposal: pumping the CO2 deep underground. There are important policy and legal issues associated with geologic storage. The implementer must obtain rights to the underground pore space and be able 

to assign liability for accidents and leakage etc. These same issues exist for storage 

of CO2 in a CCS project and the US CCS project currently deals with them. However, Keeling (R. Keeling, Triage in the greenhouse, Nature Geoscience, 2, 820–822, 

2009) has suggested that the amount of CO2 we may need to remove from the atmosphere is such that we will have to consider disposal in the deep ocean as a form 

of environmental triage. Ocean dumping would clearly involve much more serious 

governance issues, similar to climate intervention which are discussed below. 

Because of the similarities with CCS, it makes some sense to augment current 

research by DOE’s Fossil Energy program in CCS to include separation technology 

related to air capture of CO2. There are technical synergies in the chemical engineering of these processes and the researchers are in some cases the same. The research is complementary. The governance issues related to geologic storage are exactly the same. 

A second governance issue has to do with intellectual property (IP). If there is no 

significant price for carbon, and carbon removal becomes a function of the government (like picking up the garbage) we might consider making any air capture technology we develop freely available throughout the world as it is in our interest to 

have anyone who is able and willing help clean up the atmosphere. If however, 

there is a price for carbon, then IP could help to motivate innovation to gain a competitive edge which is also in the interest of society. Unfortunately, we don’t have 

a price for carbon now, and we are not sure whether we will, so the choice is difficult. 

Beyond air capture, the Royal Society report on Geoengineering (J. Shepherd et 

al., Geoengineering the Climate: Science, Governance and Uncertainty, The Royal 

Society, London, 2009 http://royalsociety.org/geoengineeringclimate/) lists a number of other carbon removal technologies. Among these, augmentation of natural 

geologic weathering processes and biological methods would fit well within either 

NSF’s science programs or in DOE’s Office of Science program. For the near term, 

research will involve the kind of modeling studies and field experiments that are 

already a mainstay of these programs. NSF is focused on university researchers and 

is extremely competitive which means that high risk ideas will likely not be funded. 

In the DOE program, there is more focus on mission, high risk research, and national laboratory researchers. There should be room for both. The US Geological 

Survey will certainly have highly applicable expertise. 

A climate remediation program should also provide money to investigate issues 

such as the possibility of putting out coal mine and peat fires that continually burn 

underground and emit large amounts of CO2 and other greenhouse gasses. With the 

demise of the US Bureau of Mines, there is no clear place for this research, but 

might be best done through the Mine Safety and Health Administration (MSHA). 

Biological methods of remediation might include genetically modified organisms 

(GMO) that would raise governance issues. Early stage research would likely be covered under existing review and governance mechanisms in place by NIH or NSF for 

other GMO research. Any large scale experimentation would also raise governance 

issues similar to those associated with climate interventions which are discussed 

below. Similarly, ocean iron fertilization methods have governance issues similar to 

climate intervention methods and may also be governed by existing treaties such as 

the London Convention or the Law of the Sea.

Climate intervention 

Climate model simulations have shown that it is possible to change the global 

heat balance and reduce temperatures on a global basis very quickly with aerosol 

injection in the stratosphere for example. We also have experience with natural analogues in the form of volcanic eruptions which emit massive amounts of sulfates 

that cause colder temperatures for months afterwards. So we have a pretty good 

idea that some methods could be effective at reducing global temperatures. 
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Climate intervention techniques include a variety of controversial methods aimed 

at changing the heat balance of the atmosphere by either reducing the amount of 

radiation reaching the Earth or reflecting more into outer space. The common features of these technologies are that they are inexpensive (especially compared to 

mitigation), they are fast acting, and they are risky. Some could lower temperatures 

within months of implementation, but they do not ‘‘solve’’ the problem in that they 

do nothing to reduce the excess greenhouse gases in the atmosphere. So, if we reflect more sunlight and don’t reduce CO2 in the atmosphere, the oceans will continue to acidify, severely stressing the ocean ecosystems that support life on Earth. 

And if we keep adding CO2 the atmosphere we will eventually overwhelm our capacity to do anything about it with geoengineering intervention. So, climate intervention cannot be a stand-alone solution. It is at best only a part of an overall strategy 

to reduce atmospheric concentrations of greenhouse gases and adapt to the unavoidable climate change coming down the pike. Climate interventions are unlikely to be 

deployed until or unless we become convinced that the risks of climate change plus 

climate intervention are less than the risks of climate change alone. 

There are ideas for putting reflectors in space and increasing the reflectance of 

the oceans, land or atmosphere (see the Royal Society Report on Geoengineering). 

Some propose global interventions such as injection of aerosols (sulfate particles or 

engineered particles) in the stratosphere and the Novim report spells out the required technical research in some detail (J.J. Blackstock et al., Climate Engineering 

Responses to Climate Emergencies, Novim, Santa Barbara, CA 2009 http://

arxiv.org/pdf/0907.5140). Others propose more regional or local interventions, such 

as injecting aerosols in the Arctic atmosphere only in the summer to prevent the 

ice from melting (On the possible use of geoengineering to moderate specific climate 

change impacts, M. MacCracken, Env. Res. Letters, 4/2009, 045107). Even more 

local and perhaps the most benign is the idea of painting rooftops and roadways 

white to reflect heat. 

The more global and effective these methods, the more they harbor the possibility 

of unintended negative consequences which may be unequally distributed over the 

planet and extremely difficult to predict. We can expect few if any unintended consequences from painting roofs white, the benefit will be real and a cost-effective part 

of our arsenal. However, this action alone is not enough of an intervention to hold 

back runaway climate change. On the other hand, we could reverse several degrees 

of temperature rise by injecting relatively small amounts of aerosols in the stratosphere (because a few pounds of aerosols will offset the warming of a few tons of 

CO2), but it may be difficult to predict exactly how the weather patterns will change 

as a result. Although the net outcome may be positive, certain regions may experience deleterious conditions. It will be very difficult to determine whether these deleterious conditions arise simply from climate variability or are due to the intentional 

intervention. In general, methods with high potential benefits also have higher risks 

of unintended negative consequences. 

Climate intervention might be part of an overall climate strategy in ways and 

with difficulties that we have only begun to contemplate. Climate model simulations 

have shown that if we were to suddenly stop a global intervention, then the global 

mean temperature will quickly return to the trajectory it was following before the 

intervention. This means that temperatures could increase very rapidly upon cessation of the intervention which would likely to be devastating. Climate intervention 

may only provide temporary respite, and ironically would be difficult to stop. However, we already emit millions of tons of aerosols now in the form of air pollution 

which is masking an unknown amount of global warming, perhaps as much as 5 

or 10 degrees C. So, as we clean up this air pollution to protect human health or 

stop emitting air pollution as we shut down coal-fired electricity generation in mitigation efforts, we will also cause a significant increase in short-term warming. (Long 

term warming remains largely a function of the concentration of CO2.) We may 

want to offset this additional warming by injecting some aerosols in the stratosphere where they are even more effective at reflecting radiation. This plan might 

cause much less acid rain and improve human health impacts compared to the 

power plant and automobile emissions while continuing to mask undesirable warming. It is possible that the ‘‘drug’’ of aerosol injection could be a type of ‘‘methadone’’ 

as we withdraw from fossil fuels. 

Beyond technical problems, international strife is possible. State or non-state actors may think it is in their interest to deploy geoengineering without international 

consensus. Could a country suffering from climate change see a benefit to the technology and not have sufficient concern with disrupting the rainfall in other countries? Any indication that a nation is doing research solely to protect their national 

interests will be met with appropriate suspicion and hostility. On the other hand, 

the possibility of reaching of global consensus to deploy these technologies seems ut-
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terly impossible. Who gets to determine what intervention we deploy or even what 

the goal of the intervention should be? 

Climate intervention techniques offer tremendous potential benefits to life on 

Earth, at the same time they are hugely vulnerable to mismanagement and may 

have severe and unacceptable unintended consequences and risks. For all these reasons, practically no one thinks we should deploy these technologies now if ever and, 

we should remain skeptical and appropriately fearful of deploying these technologies 

at any point in time. But many, including me, think we should gain knowledge 

about them in a research program simply to inform better decisions later and to be 

sure we have explored all options in light of the enormity of the threat. It would 

be especially better to know more about what could go wrong and what not to do.

In light of these concerns, how should a research program proceed? 

The nature of research into climate intervention may call for a focus on public 

management rather than private sector motivation. There is much at 

stake—literally the future of the planet. There are distinct problems with letting 

companies with vested financial interests in intervention technology have a say in 

the intervention choices we make. For example, when California decided it no longer 

had to dig up old leaking gas tanks because the bacteria in the soil were able to 

remediate the contamination if just left alone (intrinsic remediation), the industry 

that served to dig up leaking gas tanks fought the ruling. Not digging up the tanks 

was in the interest of society, but the industry was concerned with its financial future. We do not want to place the deliberations about how to modify the climate 

in a profit making discourse. The role of the private sector and public-private partnerships should be carefully constructed to avoid these problems. 

The United States Government should make it absolutely clear we are not planning for deployment of climate intervention technology. Many serious people worry 

that geoengineering will form a distraction from mitigation. Many are worried because they do not see the societal capacity to make mitigation decisions commensurate with the scale of the climate problem. Others find the very thought of 

geoengineering abhorrent and unacceptable. However, many people who are against 

deployment are 

in favor of research. By making it clear we are not planning to deploy we can take 

some of the political pressure off the research program and allow more room for 

honest evaluation. 

A very good example of how this might work can be found in the Swedish nuclear 

waste program. In 1980, Sweden voted to end nuclear power generation in their 

country in the early part of the 21St century. Then, they began a program to build 

a repository to dispose of nuclear waste. Opposition to the nuclear waste program 

was not saddled by the question of the future of nuclear power. The program proceeded in an orderly manner and with extensive public interaction and consultation 

focused narrowly on solving the nuclear waste problem. They jointly developed a 

clear a priori statement of the requirements for an appropriate site before the site 

was chosen. Today, Sweden has chosen a repository site which is supported by the 

local population and is scientifically the best possible site in Sweden. (In contrast, 

the goal of the American policy was to show that we could store waste in order to 

have nuclear power, the repository site was chosen by Congress without public consultation. Astonishingly, the site criteria were established after the site was chosen. 

In the end we do not have a successful nuclear waste storage program. See J. C.S. 

Long and R. Ewing, Yucca Mountain: Earth-Science Issues at a Geologic Repository 

for High-Level Nuclear Waste, Annual Review of Earth and Planetary Sciences, Vol. 

32: 363–401 May 2004) Likewise for geoengineering, a perception that the purpose 

of the research program is to plan deployment would saddle the research program 

with needless controversy. We should be careful to state we are not planning deployment. 

Second, as in the Swedish nuclear waste program, we should embed public engagement in the research program from the very beginning. I will discuss science 

and public engagement from three perspectives: national governance, international 

interactions, and the requirement for adaptive management.

National research governance: 

In constructing a national research program, we have to be concerned with these 

questions:

1. What constitutes appropriate levels of governance for specific types of research?

2. What are the guiding principles and values that will be used to sanction research?
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3. Given these principles, what process will be used to sanction proposed research?

4. How will the governance process engage society?

Types of research 

One of the truly difficult problems in climate intervention research has been 

pointed out by Robock et at (Science 29 Jan 2010, Vol 327, p 530). Namely, it is 

not possible to fully understand how a specific technology will work on a global 

scale, over extended periods of time without actual deployment. But we certainly 

would not want to deploy an intervention without understanding how it works first. 

We cannot plunge into deployment, so how should research proceed? 

The first key point is that there are many types of research that require no new 

governance. For example computer modeling studies that simulate proposed interventions are clearly completely benign. On the other hand, a proposal for full- or 

even sub-scale deployment with non-trivial effects would clearly require a very high 

level of scrutiny. So, the first task is to determine the scale and intensity of experimentation below which research can proceed with impunity. What amount of perturbation, reversibility, duration, impact, etc falls squarely within the existing bounds 

of normal research? I will call this the ‘‘bright line,’’ even though in practice the line 

is likely to be fuzzy and the characterization of this line is likely to be difficult to 

express quantitatively. Never-the-less, if research falls under the bright line, essentially no new governance is required. 

There is no single bright line for all proposed climate intervention research; the 

nature of the ‘‘bright line’’ is technology dependent. Although the types of questions 

might be similar, the specific questions we would ask about aerosol injection in the 

stratosphere are completely different than the questions we would ask about putting 

small bubbles on the surface of the ocean. So, when a technology is sufficiently mature to be seriously considered for expanded research, it will become necessary to 

understand the bright line for that technology. The process and deliberation used 

by the National Academy of Sciences/ National Research Council (NAS/NRC) is ideal 

for determining this bright line. They assemble a panel of experts, take testimony, 

and opine on complex scientific and social issues. Two of the technologies currently 

under discussion, aerosol injection in the atmosphere and cloud brightening, have 

probably reached this level. An NAS/NRC panel should be convened now to determine what research projects in these two technologies can proceed with ‘‘normal’’ 

governance. 

More difficult is the area of research above the bright line. The National Environmental Policy Act (NEPA) mandates federal agencies to prepare an Environmental 

Impact Statement (EIS) for any major federal action that significantly affects the 

quality of the human environment or to conduct an Environmental Assessment 

when the effects of the proposed action are uncertain. These and other environmental laws and regulations may directly affect above the line research. Beyond 

these environmental laws, governance principles and procedures are yet to be developed. 

Nanotechnology has attributes in common with climate intervention research. 

There is great promise but risks that are hard to quantify. How will nano-particles 

behave in the environment? Will they disrupt natural processes in a way we cannot 

predict? One approach has been to fund research on the toxicology of nano-particles 

to find out what might wrong. At least part of a climate intervention research program should be dedicated solely to understanding the potential negative impacts 

and what might go wrong.

Principles 

For research that rises above the bright line, there is a lot to be learned from examining other research governance principles and practices. Human subjects research is particularly apropos. The Nuremburg trials after WWII revealed horrendous medical experiments on human subjects by Nazi ‘‘doctors’’. America’s shameful 

history of research on syphilis in the 1960s and 1970s which horribly mistreated the 

Tuskegee airman and subjected them to unimaginable suffering is another salient 

reminder of how dangerous experiments may be when detached from appropriate 

moral and ethical guidelines. These experiences led to a commission charged with 

providing guidance for future research governance. The Belmont report written by 

this commission lays out principles which must be met in order to sanction proposed 

research where humans are the subject of the research. (From Wikipedia http://

en.wikipedia.org/wiki/Belmont¥Report: The Belmont Report is a report created by 

the former United States Department of Health, Education, and Welfare (which was 

renamed to Health and Human Services) entitled ‘‘Ethical Principles and Guidelines 
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for the Protection of Human Subjects of Research,’’ authored by Dan Harms, and 

is an important historical document in the field of medical ethics. ) The principles 

are quite basic and we can easily see how they might translate to principles that 

might apply to ‘‘Earth subject’’ research. 

The three fundamental principles of the Belmont report are:

1. respect for persons: protecting the autonomy of all people and treating them 

with courtesy and respect and allowing for informed consent;

2. beneficence: maximizing benefits for the research project while minimizing 

risks to the research subjects; and

3. justice: ensuring reasonable, non-exploitative, and well-considered procedures 

are administered fairly (the fair distribution of costs and benefits to potential

research participants.)

These principles stimulate a good discussion of possible governance principles for 

geoengineering. For the first principle, there are really two parts, respect and informed consent. The respect part probably translates to ‘‘Respect for all persons of 

the planet.’’ Geoengineering research should not be frivolous, or dismissive of 

human life. As well, life other than human is also an issue, so perhaps this principle 

translates to ‘‘respect for life on Earth’’. Does the proposed research exhibit respect 

for life on Earth? 

The informed consent principle is perhaps the most important and most vigorously evaluated principle in human subjects research review. Proposals are rejected 

based on obfuscation of the research methods. For example, a proposal for research 

on child molestation was recently rejected. The proposer told parents he would be 

playing a game of Simon Says with the children. What the proposer failed to tell 

the parents was that he would ask the children to do things like ‘‘suck my thumb’’. 

The proposal was denied based on lack of informed consent. The message here is 

that the researcher obscured the procedure in order to get consent from the parents. 

What is the moral equivalent of informed consent for geoengineering research? I 

think it is at least in part that the proposal methods, plans, analysis and even engineering should be open and transparent. We might ask researchers for specific actions to make their work transparent and collaborative. Say posting on a specific 

website, or advertisements in new media. Beyond this, it is not possible to get the 

informed consent of all life on Earth or even all countries. The question will be who 

is informed and who has to consent? How will the public and the democratic process 

be involved? These are matters for public deliberation. 

The beneficence principle applies essentially without change. It is perhaps the 

most straightforwardly applicable of the three. The benefits of the research should 

outweigh the risk of unintentional harm to life on Earth. The research must be 

aimed at accomplishing a benefit and must not intentionally do harm. To demonstrate this, proposers should take actions such as modeling their results, evaluating natural analogues, assessing potential impacts, and other due-diligence measures that, in the end, must be evaluated by judgment in review. Again, the question 

is, who reviews? Who gets to sanction the research? We can examine the review 

process used for human subjects and other controversial research and learn more 

about what we should do for climate intervention research. 

The third principle, justice, requires somewhat different articulation for 

geoengineering, but the basic ideas apply. The intent of this principle is to avoid 

experiments that take unfair advantage of a class of vulnerable people (prisoners 

or children for example) for the benefit of others. In the case of Earth subject research, the issue might be this: does the proposed activity sacrifice the interests of 

one group of people for the benefit of everyone else? I would think that at the research level, the answer to this question should be categorically ‘‘no’’, the research 

does not gain information about a proposed method at the expense of vulnerable 

populations. Proposers could be required to show how and why they expect their research to be fair. The problem will become more difficult as research reaches 

subscale or full scale deployment. If some parts of the Earth are harmed by the 

intervention, will there be compensation, how much and from whom? How will causation be established? Worse, is it fair to deprive some countries of the right to 

choose the temperature? These questions themselves must be topics for research 

and public deliberation. 

There are of course major differences between the ethics governing medical research on human subjects and Earth subject research. One of the most interesting 

is that the need for research governance is diminished over time for medical research. Eventually, if the research is successful, protocols with statistical results to 

support them are obtained. The research results can be used to set standards of 

practice and the ethics become ethics of normal medical practice. The need for re-
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search review declines with time. In the case of geoengineering the research aspects 

are likely to continue indefinitely, and may become more acute with time. We cannot do double-blind studies. We cannot have a statistical sample of Earths. At some 

level, geoengineering, will always be research and always require research-ethics 

type governance. And the worst case from a risk perspective is actual implementation. Whereas in medical research, the need for governance subsides over time, for 

geoengineering, governance will get more and more pronounced over time, until or 

unless the idea is abandoned.

Review Process 

In human subjects research, Institutional Review Boards (IRBs) are vested with 

the authority to review and sanction research. These boards review the research 

protocols and procedures to insure they meet ethical standards. If the IRB approves 

the research, then the institution is free to allow the research to be conducted. If 

the IRB disapproves, the institution may not conduct the research as proposed. The 

IRB cannot decide that the research will be done, only that it may be done. IF the 

IRB disapproves, the institution must comply with the ruling and cannot allow the 

research to continue. 

There are perhaps three salient features of the IRBs that control the outcomes. 

First, they are part of the research institution. They are not an external body. However, once appointed, they are independent. Second, their rulings are not based on 

specific regulations. They are based on principles which are derived mainly from the 

Belmont report. Third, the board membership is defined by federal code: http://

www.accessdata.fda.Rov/scripts/cdrh/cfdocs/cfCFR/CFRSearch.cfm?fr=56.107. 

This guidance specifies that each IRB must have at least five people, members must 

include those qualified to review the research and members from the community. 

So, it is the principles and the board appointments that insure the quality of the 

IRB decisions. 

It is notable that IRB’s from around the country meet regularly together and 

present prior cases without revealing their ultimate decisions until after the cases 

are discussed. Then the board that presented the case reveals the decision they actually made. In this way, the boards gain insight and skill at making difficult rulings. The point is, their rulings are not prescriptive, they are based on judgment 

and good judgment requires learning. 

The IRB’s have public members in order to protect public interests. Even so, dissatisfaction with this process arises from a sense that IRBs end up rubber-stamping 

research protocols, do not deliberate conflict of interest issues, and do not engage 

in any real public dialogue about values. Consequently, researchers and social scientists are experimenting with new models to engage the public in human subjects 

research. 

Given the problems with governance of human subjects research, it would be wise 

to develop a program that seeks to propose and test research governance and engagement models. One of the best ways to learn about what works is to go through 

exercises in mock governance. For example, an institution or project could try out 

a governance process in a ‘‘moot court’’ type trial such as this:

• A draft set of guiding principles for research is given to blue and red teams. 

They might start with the principles outlined above for example. Both teams 

should include scientists, but also might include members of the public or social scientists.

• Blue teams would prepare mock (or real!) research proposals for 

geoengineering field tests and gives these to the red teams. For example, a 

team may propose an Arctic sulfate injection or mid ocean for cloud whitening 

trial.

• Red teams prepare critiques of the blue team proposals. The job of the red 

team is to try to find the weaknesses in the blue team proposal and bring 

these to light.

• Both teams present the research and critique respectively to a mock review 

board at the meeting following the draft guidelines/principles. We might 

choose the people for the mock board as a mix of scientific backgrounds and 

a strong mix of public interest members as well as ethicists or philosophers—ie far beyond the IRB membership as specified in the federal statute.

• The mock board uses the draft principles to evaluate the proposals. They 

could issue a mock ruling to sanction the research, turn the proposal down, 

or perhaps recommend additional measures for due diligence.
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• Everyone discusses the process—did the principles cover the important 

issues? —was the process appropriate? How might the process go wrong? The 

goal should be to identify all salient lessons learned.

• Do this again changing the process as appropriate.

Another set of exercises are being tried in the field of nanotechnology research 

to incorporate the values of society. David Gustin, for example, describes experiments in ‘‘anticipatory governance’’ (Gustin, Innovation policy: not just a jumbo 

shrimp, Nature, Vol 454/21, August 2008). There are three parts to this process. The 

first part is designed to educate the public about the nature of the research and to 

bring public deliberation of values into the open. The second part is to have scientists and the public collaborate on imagining how the future might unfold given 

new technology and social trends. Gustin calls this ‘‘anticipatory knowledge’’. Discussions then give voice to public concerns about the future. Finally, the public engagement and anticipatory knowledge are integrated with the research. For example, social scientists and humanists have become ‘‘embedded’’ in nanotechnology research labs. They help the scientists reorient their work in more socially acceptable 

directions. This could also be a very good model for geoengineering. It would be possible to create a geoengineering forum where publics could be informed and express 

concerns. Exercises that highlight the possible futures with and without 

geoengineering would help all to understand how we should focus. Finally, keeping 

social scientists are part of any scientific research team may help with both guiding 

the research towards more socially acceptable directions and also help scientists 

with communication and outreach. 

There is no absolute clear answer to the question how to govern geoengineering 

research. The fact is that we need research and experimentation to understand how 

to govern this research, ie research and experimentation on how to govern research 

with public engagement. It is likely that research governance models will be different for different types of technologies and there will not be a one-size-fits-all governance model. As technologies reach the stage of research that approaches the 

‘‘bright line’’, specific governance models should be explored and evaluated.

International governance: 

Geoengineering research has the potential to cause international conflict. Tensions could easily rise if countries perceive that the research is being conducted solely for national interests. If geoengineering research programs became part of defense research programs, it would certainly convey the message that the goal was 

to advance national interests. Consequently, research programs should explicitly 

only develop technology that will have international benefits. Research should not 

be managed by national defense programs (J. J. Blackstock and J. C. S. Long, The 

politics of Geoengineering, Science, Vol 327, p. 527, 29 Jane 2010.) 

Secrecy also has the potential to create tension and conflict. It is important that 

geoengineering research be conducted in the open with results published in the open 

literature. Especially in the early stages, a pattern of trust and consultation will be 

critical to a future that might well require agreement and collaboration. Inclusion 

of international scientists in a national research program or the 

establishment of international research programs would have tremendous benefits 

in both expanding the knowledge base and as an investment in future collaboration. 

In starting down a research path, we must remember that critical decisions about 

deployment may be needed someday and that these decisions should not be made 

unilaterally. We should be extremely careful not to increase tensions or 

misperceptions that would make these decisions even harder. On the other hand, 

there is less and less confidence that all affected nations would ever be able to come 

to an agreement and sign a treaty to support a single set of actions. Such a treaty 

may still be our goal, but there are other strategies that can help us to make good 

choices together. I am fond of a quotation from the famous French sociologist, Emil 

Durkheim in which he noted: ‘‘Where mores are strong, laws are unnecessary. 

Where mores are weak, laws are unenforceable.’’ In that spirit, we may hope that 

good cooperative relationships in geoengineering research and research governance 

may help to develop common norms of behavior and it may be these norms that provide the capacity to make good collaborative decisions in the future.

Adaptive management 

Climate is a complex, non-linear system with many moving parts. When we set 

about to intentionally intervene in climate outcomes, there will always be uncertainty about whether our chosen actions will result in the desired outcomes. An essential feature of any climate intervention will be the need to provide for adaptive 
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management, also known as ‘‘learning by doing’’. If we are to use adaptive management in a climate intervention it means that we

1. Choose to make an intervention,

2. Predict the results of the intervention,

3. Monitor the results of the intervention,

4. Compare the observations to the predictions,

5. Decide if we are going in the right direction and

6. Make a new set of decisions about what to do.

(See http://en.wikipedia.org/wiki/Adaptive¥management.). In the real world it is 

very hard to actually do adaptive management. 

First, it is difficult enough to make a decision to act. To then change this decision 

becomes confusing and politically negative. Consequently, successful adaptive management establishes a structure for the adaptive modification a priori. So, regular 

intervals and formats are established for comparing observations with predictions 

and a formal requirement is put in place for deciding whether or not and when to 

change directions. When this process is specified up front, it can avoid the political 

fallout of changing direction. Part of a geoengineering research program should examine the potential policy and institutional frameworks for conducting adaptive 

management. In particular it is important to determine a priori how the technical 

and political parts of the process will interact. Will the deciding entity be a board 

made up of scientists and policy makers and perhaps members of the public and 

social scientists? 

Or should we structure a hierarchy of decision makers where higher level boards 

have decisions about overall direction, but less control of specifics? 

Second, you must have a very good data base of observations. If you haven’t made 

extensive observations all along, how will you be able to detect what is changing? 

This is not just a problem for geoengineering, but for all of our climate strategies. 

The observation network we have for climate related data is far too sparse and in 

some cases, inadequately calibrated. We need a major commitment for all our climate research to collecting and calibrating data relevant to climate change on a continuous, ubiquitous basis and perpetual basis. This is a sine qua non recommendation for any climate solution. We cannot rewind the tape and go back to collect data 

that we failed to collect over time. The observation network for climate is inadequate to our needs and this is an extremely high priority for research dollars. 

Third, you must be able to discern whether a change is attributable to simple climate variability or to the specific intervention. The science of detection and attribution of human effects on climate has advanced tremendously in the past decades. 

But the challenge of detecting and attributing changes to intentional, fairly short 

term interventions has not been met. This must be a focus of research. As it is 

strongly related to the existing climate science program, the expanded work belongs 

there. 

In the simplest terms, the scientific approach to attribution of human induced climate change—whether through unintentional emissions or intentional climate intervention—is to use climate models to simulate climate behavior with and without the 

human activity in question. If the results of the simulations including the activity 

clearly match observations better than the results without the activity, then scientists say they have ‘‘fingerprinted’’ the activity as causing a change in the climate. 

Perhaps the most famous illustration in the International Panel on Climate Change 

(IPCC) reports shows two sets of multiple model simulations of mean global temperature over the twentieth century, one with and the other without emitted greenhouse gases. On top of this plot, the actual temperature record lines up squarely 

in the middle of the model results that included greenhouse gas emissions. This plot 

is a ‘‘fingerprint’’ for human induced warming. Scientists have gone far beyond 

mean global temperature as a metric for climate change. Temperature profiles in 

the atmosphere and ocean, the patterns of temperature around the globe and even 

recently the time of peak stream flow have been used to fingerprint human induced 

warming. 

Structured climate model intercomparison projects are fundamental to drawing 

fingerprinting inferences. No single model of the climate gets it all right. Each climate model incorporates slightly different approaches to approximating the complex 

physics and chemistry that control climate outcomes. So, we use multiple models all 

running the same problems. We can then examine a statistical sample of results 

and compare this to data. In a form of ‘‘wisdom of the crowd’’, the mean of all the 

model results has proven to be a better overall predictor of climate than any single 

model. 
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The science of fingerprinting is becoming more and more sophisticated. Increasingly, scientists are looking at patterns of observations rather than a single number 

like mean temperature. Patternmatching is a much more robust indicator of causality because it is much harder to explain alternative causality for a geographic or 

time-series pattern than for a single value of a single parameter. A famous example 

of this was discerning between global warming caused by emissions versus caused 

by a change in solar radiation. Solar radiation changes could not account for the 

observed pattern of cooling of the stratosphere occurring simultaneously with a 

warming of the troposphere, but this is exactly what models predicted for emission 

forced climate change. There exist ‘‘killer metrics’’ like this that tightly constrain the 

possible causes of climate observations. 

We are making progress on the ‘‘holy grail’’ of using present observations to predict future climate states. Recently, Santer et al showed that it possible to rank individual models with respect to their particular skill at predicting different aspects 

of future climate. Interestingly, the models fall into groups. The top ten models that 

get the mean behavior right are different than the top ten models that get the variability right. (Santer et al., PNAS 2009, Incorporating model quality information in 

climate change detection and attribution studies, http://www.pnas.org/content/

106/35/14778.full?sid=e20c4c31-5ab1-4f69-b541-5158e62e4baf). 

Some think that the ability to detect and attribute intentional climate intervention will be nearly impossible. The fingerprinting of human induced climate change 

has been based on decades of data under extremely large human induced perturbations. For climate intervention, we contemplate much smaller perturbations and 

would like proof positive of their consequences in a matter of years. Even though 

this is clearly a big challenge, it is not hopeless. Neither should we expect a panacea. We will be able to identify specific observations that certain models are better 

at predicting and we will be able to find some ‘‘killer metrics’’ that constrain the 

possible causes of the observations. In some respects, conclusive results will not be 

possible and we will have to learn how to deal with this. Fingerprinting—detection 

and attribution of human intervention effects on climate—must be an important 

area for research if we are to be able to conduct adaptive and successful management of geoengineering. As this topic is closely interconnected to basic climate 

science, the program to extend research into intentional intervention should belong 

in the US Climate Science Program. 

A geoengineering research program should include the development of technology 

and capacity for adaptive management.

The ‘‘Catch-All’’ Category 

Recent studies have shown vast amounts of methane, a powerful greenhouse gas, 

are leaking from the Arctic Ocean floor. Billions of tons of methane are stored in 

permafrost and will be released as the frozen lands thaw. Methane is a green house 

gas that is approximately 25 times more powerful than CO2. Abrupt increases in 

methane emissions have been implicated in mass extinctions observed in the geologic record and could trigger runaway climate change again. (It is the possibility 

of such runaway climate change that most clearly supports the need for 

geoengineering research.) James Cascio recently posed an idea for deploying genetically engineered methanotrophic bacteria (bacteria that eat methane) at the East Siberian Ice Shelf (http://ieet.org/index.php/IEET/more/3793/). Is this possible? 

Could bacteria survive in the Arctic? Could they eat the methane fast enough to 

make a difference? 

What are the risks? Could release of genetically modified methanotropic organisms cause problems to the Arctic ecosystems? Is the idea worth pursuing? This 

may be an idea with merit -or it may be a very stupid idea. 

Somewhere in the geoengineering research program there should be funding to 

freely explore theoretical ideas and perform the modeling and laboratory studies to 

determine which concepts are worthy of more work, and which are completely impractical or too dangerous. This should be a ‘‘gated’’ research program wherein small 

amounts of funding are provided to explore many out-of-the-box ideas with thought 

experiments, modeling and laboratory experiments as appropriate. At this stage, 

none of the research ideas should require more than traditional governance mechanisms provided by existing research programs. At the end of this initial funding, the 

concepts would have to be reviewed and if they are deemed to have promise, then 

they would become eligible for more funding. If the ideas are found to be lacking 

in merit, then they would be shelved. Several stages or gates should be set up with 

increasingly higher bars so that a large number of ideas can be generated at the 

first gate, but these are increasingly winnowed down as we learn more about their 

practicality, dangers and effectiveness. 
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Beyond this ‘‘bottom-up’’ approach, there should be a ‘‘top-down’’ research program 

that examines potential emergencies that could result from climate change and then 

attempts to design interventions for these specific situations. The primary climate 

interventions currently under discussion attempt to reduce temperature. Although 

higher temperatures that result from climate change will be a severe problem, I 

would argue that other impacts of climate change might be more critical. For example, one of the major impacts of climate change will be increased water stress—we 

will need more water because it is hotter and there will be less water because there 

will be more droughts. Water shortage will lead to problems with food security. A 

choice to control temperatures with aerosol injection for example might result in reduced precipitation. Volcanic eruptions such as Pinatubo provide a natural analogue 

for such aerosol interventions. Gillett et al. were able to show that a result of these 

eruptions caused a reduction in precipitation (Gillett, N.P., A.J. Weaver, F.W. 

Zwiers, and M.F. Wehner, 2004: Detection of volcanic influence on global precipitation, Geophysical Research Letters, 31, doi: 10.1029/2004GL020044.). So, we might 

reduce temperatures with aerosols, but make hydrological conditions worse. Reducing precipitation would clearly be a bad thing to do. By looking only at what we 

know how to do (reduce temperatures) vs what problem we want to solve (increase 

water supply), we could be making conditions worse. Geoengineering research 

should not only be structured around ‘‘hammers’’ we know about. We should also 

collect the most important ‘‘nails’’ and see if we can design the right hammer. 

Thus, we might try to develop methods that directly attack specific climate impacts. Can we conceive of a way to control the onset, intensity or duration of monsoons to ensure successful crops in India? Can we conceive of a way to stop methane 

burps, or hold back melting glaciers? Some part of a geoengineering research program should take stock of the possible climate emergencies and then look for ideas 

that would ameliorate these problems.

Conclusions 

The above comments describe a number of measures we might take in establishing a geoengineering research program. If we are to have a successful research 

program we must be careful about public engagement, principled actions, transparency, international interaction and adaptive management. We will have to build 

the capacity to develop rational options coupled to the capacity to make rational decisions about deploying them. If we succeed, it may be that these capacities spill 

over into other difficult climate problems. We may ask in the end: Are we building 

the capacity to do geoengineering or using geoengineering research to build capacity 

for any climate solution? If we are lucky, the answer will be the latter.

BIOGRAPHY FOR JANE LONG

Dr. Long is currently the Principal Associate Director at Large for Lawrence 

Livermore National Laboratory working on energy and climate. She is also a Fellow 

in the LLNL Center for Global Strategic Research. Her current interests are in 

managing climate change including reinvention of the energy system, adaptation 

and geoengineering. From 2004 to 2007, as Associate Director, she led the Energy 

and Environment Directorate for the Lawrence Livermore National Laboratory. The 

Energy and Environment Directorate included programs in Earth System Science 

and Engineering, Nuclear System Science and Engineering, National Atmospheric 

Release Advisory Center, and the Center for Accelerator Mass Spectrometry. In addition, the directorate included 12 disciplinary groups ranging from Earth sciences, 
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to energy efficiency to risk science. From 1997 to 2003 Dr. Long was the Dean of 

the Mackay School of Mines. The Mackay School of Mines had departments of Geological Sciences, Mining Engineering and Chemical Engineering and Materials 

Science and Engineering as well as the Nevada Seismological Laboratory, the Nevada Bureau of Mines and Geology and the Keck Museum. Dr. Long led the University of Nevada, Reno’s initiative for renewable energy projects and served as the Director of the Great Basin Center for Geothermal Energy and initiated the Mining 

Life-Cycle Center. Prior to this appointment, Dr. Long worked at Lawrence Berkeley 

National Laboratory for 20 years. She served as Department Chair for the Energy 

Resources Technology Department including geothermal and fossil fuel research, 

and the Environmental Research Department. She holds a bachelor’s degree in engineering from Brown University and Masters and Ph.D. from U. C. Berkeley. 

Dr. Long has conducted research in nuclear waste storage, geothermal reservoirs, 

petroleum reservoirs and contaminant transport. For the National Academy of 

Sciences, Dr. Long was chairman of the US National Committee for Rock Mechanics, the Committee for Fracture Characterization and Fluid Flow and a committee 

to recommend a research program for the Environmental Management Science Program for DOE. She served on the NAS/NRC Board on Radioactive Waste Management, as well as several study committees under the aegis of this board, and had 

been a member of the Board on Energy and Environmental Systems. In 2001, she 

was appointed as a member, subsequently chair of the State of Nevada Renewable 

Energy Task Force. She is an Associate of the National Academies of Science, member of the Stanford University College of Earth Sciences Advisory Board, the Energy 

and Environment and National Security Visiting Committee for Brookhaven National Laboratory, the Intercampus Advisory Board for the UC Energy Institute, the 

chairman for the mitigation advisory committee of the NAS Koshland Science Museum’s Climate Change exhibition, and member of the Governor’s Task Force on California’s Adaptation to Climate Change sponsored by the Pacific Council. Dr. Long 

currently co-chairs the ‘‘California’s Energy Future’’ study being conducted by the 

California Council on Science and Technology (CCST) and was recently elected as 

a Senior Fellow of CCST. She is a member of the National Commission on Energy 

Policy’s Task force on Geoengineering. She has been a member of the UC Berkeley 

Department of Nuclear Engineering Advisory Board, the Colorado School of Mines 

Department of Geophysics Advisory Board, and the American Geological Institute 

Foundation Board.

Chairman GORDON. Thank you, Dr. Long, and Dr. Barrett is recognized. 

STATEMENTS OF DR. SCOTT BARRETT, LENFEST PROFESSOR 

OF NATURAL RESOURCE ECONOMICS, SCHOOL OF INTERNATIONAL AND PUBLIC AFFAIRS AND THE EARTH INSTITUTE AT COLUMBIA UNIVERSITY 

Dr. BARRETT. Thank you very much, Chairman Gordon, and 

thank you other Members for this opportunity. 

Climate change is a real risk, and we have to do five things to 

limit that risk. First, we need to reduce global emissions of greenhouse gases. Second, we need to invest in research and development to develop new technologies to allow us to reduce emissions 

at lower cost in the future. Third, we need to prepare to adapt, and 

to assist more vulnerable countries to adapt. Fourth, we need to develop technologies that can remove carbon dioxide directly from the 

atmosphere. 

And finally, we need to contemplate the possibility of using 

geoengineering, which I will define as being a technology that can 

address global warming without affecting the concentration of 

greenhouse gases in the atmosphere. Solar radiation management 

[SRM] might be a shorthand for what I just said. 

I think it is helpful to look at this problem from two different 

perspectives. One is from that of the perspective of the world as a 

whole, and the other is the perspective of individual countries. 
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Let us start with the perspective of the world as a whole. I think 

there are four different options for thinking about deployment of 

geoengineering. The first one would be we just ban it, and there 

are a lot of people, I think, their first instincts would be that we 

should ban it. But then, you have to imagine going forward. 

Suppose we are in the situation where we start to see the worst 

fears of abrupt, catastrophic climate change appearing. At that 

point, the only thing we could do that would have any impact, 

would have an immediate impact, would be to use geoengineering. 

So, I believe that a ban on geoengineering, although I understand 

the instinct, I believe it would not be a credible policy, or even a 

responsible policy. 

The second thing we could do would be to rely entirely on 

geoengineering, a quick fix and an easy way of dealing with this 

problem. That would also be irresponsible, because this is a risk 

problem, and that would be putting all our eggs in one basket. 

Also, of course, the geoengineering that we are discussing won’t address other problems, such as ocean acidification. 

The third thing we might do is start using geoengineering, actually fairly soon, in conjunction with, say, emission reductions or 

other policies. And the fourth thing that we might do would be to 

develop the technology, and to keep it in reserve, should the moment arise in the future where we do face this scenario of abrupt 

and catastrophic climate change. 

I have looked at all four options, and I think a case can be made 

for the last two. I think a case may not be made for the first two. 

So, let us look at this issue now from the perspective of individual countries, and I think two scenarios are relevant. One is the 

scenario of gradual climate change. This is kind of the slow unfolding of climate change over time. And what we know about this scenario is that it produces winners and losers. 

Now, the losers—and I have done some back of the envelope calculations—the losers may find it in their interests to want to use 

geoengineering to offset the effects of what I will call global warming. The problem is that if that kind of climate change creates winners and losers, the use of geoengineering will also create winners 

and losers. So, this is a situation in which there will be, I would 

say international tensions and possibly conflict. 

I actually think, though, that when you have a situation like 

this, there are incentives there for the conflict to be resolved, and 

I am going to come back to that a little bit later. I don’t worry 

about geoengineering wars. 

The second scenario that I think is relevant would be abrupt and 

catastrophic climate change. In that scenario, opinion around the 

world is going to be very uniform, and a lot of countries are going 

to want to contemplate the use of this technology. So, I think in 

that scenario, clearly, you don’t have a problem of international 

conflict. 

In both cases, though, I think we need to contemplate the development now of rules, because rules will reduce uncertainty, and 

uncertainty is something we want to manage these risks. And in 

particular, I think we need rules for the possible use of 

geoengineering, as well as for research and development into 

geoengineering. 
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And the essential thing to understand about this is that we also 

need rules, we need international arrangements to reduce emissions, but the incentives for countries to reduce emissions individually are relatively modest, even though collectively, we would be 

much better off if all countries took action. So, we have a colossal 

free-riding problem. 

But geoengineering is exactly the opposite. It would be something a country could do its own, and the costs, as we understand 

them today, are sufficiently low that it may be in one country’s interest, or a small coalition of countries’ interests, to actually use it. 

So, for the one issue, reducing emissions, you want to encourage 

countries to act. On geoengineering, you want to do the opposite. 

You want to restrain countries from acting, when that action would 

be opposed and may possibly harm other countries. 

Now, what kind of rules would we need to address 

geoengineering? I can think of seven that would be relevant right 

now. The first is that we need to understand that geoengineering 

is only one of, as I said, five things we need to do to reduce the 

risks associated with climate change, and I think that 

geoengineering should be embodied within an agreement like the 

Framework Convention on Climate Change, so we can balance all 

those risks. 

Second, we should make that agreement open for all countries to 

participate, since all countries would be affected. Third, the focus 

of the agreement should be on what countries can agree on, and 

not what they cannot agree on. Fourth, there should be a requirement that states must declare, announce that they will use 

geoengineering. There should be prior information about that. 

Fifth, there should be an obligation for countries to cooperate, to 

resolve any conflicts. And finally, we should be seeking a seeking 

a consensus. And then, finally, on research and development, we 

should have transparency, and I would also encourage international cooperation. 

I think the final point to make is that we need not only to understand the technology, but also, to build trust. Thank you. 

[The prepared statement of Dr. Barrett follows:]

PREPARED STATEMENT OF SCOTT BARRETT

There are two ways to look at the policy challenges posed by the threat of global 

climate change. The first is ‘‘top down,’’ from the perspective of the world as a 

whole. Looked at in this way, the fundamental challenge is to reduce risk. The second is ‘‘bottom up,’’ from the perspective of each of nearly 200 countries. Looked at 

in this way, the fundamental challenge is to realign incentives. Ultimately, the aim 

of policy should be to realign incentives so that states will make choices, either on 

their own or in concert with others, that serve the same purpose as the first perspective—choices that reduce global risks. 

Reducing global risks requires that we do five things. First, we need to reduce 

global emissions of greenhouse gases. Second, we need to invest in research and development and demonstration of new technologies so that we can reduce global 

emissions substantially, and at lower cost, in the future. Third, we need to adapt, 

and help vulnerable countries to adapt. Fourth, we need to invest in technologies 

that can directly remove greenhouse gases from the atmosphere. Finally, we need 

to consider the possible role that geoengineering can play in reducing global risks. 

The important point is that geoengineering’s role should be looked at in the context of all the other things we need to do, just as these other things should now 

be looked at in the context of us possibly choosing to use geoengineering.
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Defining geoengineering

The term ‘‘geoengineering’’ lacks a common definition. I take it to mean actions 

taken deliberately to alter the temperature without changing the atmospheric concentration of greenhouse gases. More formally, the temperature is determined by the 

amount of incoming shortwave radiation and outgoing longwave radiation. Actions 

to limit concentrations of greenhouse gases seek to increase the amount of longwave 

radiation emitted by the Earth. Geoengineering options, as defined here, limit the 

amount of shortwave radiation absorbed by the Earth. 

Some people define the term more broadly, to include interventions that remove 

greenhouse gases directly from the atmosphere. This approach to reducing risks is 

very important. It was the fourth of the five things I said we need to do to reduce 

risks. But it is very different from technologies that reduce incoming shortwave radiation, which is why I think it is better to distinguish between these approaches. 

Industrial air capture, assuming that it can be scaled to nearly any level, would be 

a true backstop technology. It is a nearly perfect substitute for reducing emissions. 

Changes in shortwave radiation—as defined here, ‘‘geoengineering’’ techniques—are 

an imperfect substitute for efforts to reduce emissions. 

There are four basic ways to change incoming shortwave radiation—by increasing 

the amount of solar radiation reflected from space, from the stratosphere, from lowlevel clouds that blanket the skies over parts of the ocean, and from the Earth’s surface. There are significant differences as between these approaches. There are interesting questions as to whether one approach may be better than the others, whether 

combinations of approaches may be better still, and whether new approaches, as yet 

unimagined, may be even better. In my testimony, I shall ignore all these distinctions and consider ‘‘geoengineering’’ as a generic intervention.

Geoengineering and related risks

From the perspective of risk, reducing emissions is a conservative policy. It means 

not putting something into the atmosphere that is not currently in the atmosphere. 

Energy conservation is an especially conservative policy for reducing climate change 

risks. 

Adaptation lowers the damages from climate change. It would therefore reduce 

the benefit of cutting emissions. In other words, adaptation is a substitute for reducing emissions. It is often asserted that these approaches are complementary. What 

people mean by this, however, is that we will need to do both of these things. This 

is true; we should reduce emissions now and we will need to adapt in the future 

and make investments today that will help us to adapt in the future. But it is also 

true that the more we reduce emissions now, the less we will need to adapt in the 

future; and the more able we are to adapt to climate change in the future, the less 

we need to reduce emissions now. 

R&D and demonstration is a complement to emission reductions. As we invest 

more in these activities, the costs of reducing emissions will fall. As we do more 

R&D, we will therefore want to reduce emissions by more; and the more we want 

to reduce emissions, the more we will want to spend on R&D. 

Air capture is a substitute for reducing emissions, but it could be a more flexible 

option. Emission reductions, by definition, cannot exceed the ‘‘business as usual’’ 

level. Air capture, by contrast, can potentially remove more greenhouse gases from 

the atmosphere than we add to it. Only air capture can produce ‘‘negative’’ emissions. 

Geoengineering is also a substitute for reducing emissions. It would be used to 

reduce climate change damages. One reason often mentioned for not considering 

geoengineering is the fear that, if it were believed that geoengineering would work, 

less effort would be devoted to reducing emissions. But if we knew that 

geoengineering would work, and if the costs of geoengineering were low relative to 

the cost of reducing emissions, then it would make sense to reduce emissions by 

less. 

As noted before, however, geoengineering is an imperfect substitute for reducing 

emissions. For example, geoengineering would not address the problem of ocean 

acidification. Also, we don’t know if geoengineering will work, or how effective it will 

be, or what its full side effects will be. We may contemplate using geoengineering 

to reduce climate change risks, but using geoengineering would introduce new risks. 

It would mean trying to reduce the risks of one planetary experiment (adding greenhouse gases to the atmosphere) by carrying out another planetary experiment (reducing shortwave radiation). As compared with reducing emissions by promoting energy conservation, geoengineering is a radical approach to reducing climate change 

risks. 
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We need to be careful how we think about this. We can reduce emissions somewhat by means of energy conservation, even using existing technologies. To reduce 

emissions dramatically, however, will require other approaches. It is difficult to see 

how emissions could be reduced dramatically without expanding the use of nuclear 

power. This may mean spread of this technology to countries—many of them nondemocratic—that currently lack any experience in using it, increasing the risk of 

proliferation. It would certainly mean the need to dispose of more nuclear waste. 

Abatement of emissions can thus also involve risks. 

I mentioned before that ‘‘air capture’’ is a near perfect substitute for reducing 

emissions. But if the carbon dioxide removed from the atmosphere were stored in 

geologic deposits, it might leak out or affect water supplies. If it were put into the 

deep ocean, it may harm ecosystems the importance of which we barely understand. 

It would also, after a very long time, be returned to the atmosphere. This technology 

also involves risks. 

The main point I am trying to make here is that we face risk-risk tradeoffs. 

Geoengineering would introduce new risks even as it reduced others. But the same 

is true, more or less, of other approaches to reducing climate change risk. Adaptation maybe an exception (we don’t yet know this; there may be some kinds of adaptation that introduce new risks), but adaptation, like geoengineering, is an imperfect 

substitute for reducing emissions. 

I can imagine some people thinking that we can address the challenge entirely 

through energy conservation and by substituting renewable energy for fossil fuels. 

Some people might think that we can do this while also closing down all our existing nuclear power plants. It might even be believed that we could do this without 

having to remove carbon dioxide from the atmosphere and storing it underground. 

All these choices are certainly feasible. But they will also be costly. The question 

is whether people are willing to bear this cost in order to reduce the associated 

risks. 

Even if we make all these choices, risks will remain. The threat of climate change 

has now advanced to the stage where every choice we make requires risk-risk tradeoffs. Many people believe that it is imperative that we limit mean global temperature change to 2 degrees Celsius. Indeed, some people believe that we ought to limit 

temperature change to no more than 1.5 degrees Celsius. Due to ‘‘climate sensitivity’’ and long delays in thermal responses, however, there is a chance we may 

overshoot these targets, even if we reduced global emissions to zero immediately. 

People who believe we must stay within these temperature limits should be especially open to the idea of using geoengineering. Alternatively, if they perceive that 

geoengineering is the greater threat, then they should reconsider the imperative of 

staying within these temperature change bounds.

Policy options for deployment

There are four main options. 

First, we could ban geoengineering. One reason for doing so would be that use 

of geoengineering poses unacceptable risks. Another reason would be that, if use of 

geoengineering were banned, efforts to reduce emissions would be shored up. 

One problem with this proposal is that, as already mentioned, our other options 

also pose risks. We need to be rational and consistent in how these risks are balanced. 

Another problem is that a ban lacks credibility. Suppose that our worst fears 

about the future start to come true, and we are confronting a situation of ‘‘runaway 

climate change.’’ At that point, adaptation would help very little. Air capture would 

reduce concentrations only over a period of decades, and because of thermal lags it 

would take decades more before these reductions translated into significant temperature change. Meanwhile, the climate changes set in motion could, and probably 

would, be irreversible. The only intervention that could prevent ‘‘catastrophe’’ would 

be geoengineering. If we had banned its use before this time, we would want to 

change our minds. We would change our minds. 

In a referendum thirty years ago, voters in Sweden supported a phase-out of nuclear power. Today, the government says that new reactors are needed to address 

the threat of climate change. Polls indicate that the public supports this change. 

Bans can be, and often are, reversed. 

Second, we could make geoengineering the cornerstone of our climate policy, and 

not bother to reduce emissions or do the other things I said we needed to do. One 

reason would be that this would spare us from having to incur costs in the short 

term. Another is that we wouldn’t need to take action until uncertainties about 

climate change were revealed. Geoengineering would be a ‘‘quick fix.’’
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A problem with this proposal is that we may find that geoengineering does not 

work as expected. It may not reduce temperature by much, or it may change the 

spatial distribution of climate. It may, and probably would, have unexpected side 

effects. We know it would not address ocean acidification. But it might also fail to 

address the ‘‘catastrophe’’ we face at that particular time, even if worked precisely 

as expected. For example, this catastrophe may be due to ocean warming, which 

geoengineering could alter only over a long period of time. Putting all our eggs, as 

it were, in the geoengineering basket would be reckless. 

Third, we could use geoengineering soon and in combination with emission reductions, as suggested by Wigley (2006). By using geoengineering soon, we could prevent global mean temperature from increasing, or from increasing by much. By reducing emissions we could avoid serious climate change in the future. We could 

limit ocean acidification. We could also avoid the need to use geoengineering in the 

future. As noted before, it is extremely unlikely that we could limit global mean 

temperature change to 1.5 degrees Celsius by reducing emissions only. The goal is 

likely to be achievable only if we used air capture or geoengineering or a combination of the two approaches in addition to reducing emissions. By extension, the same 

may also be true for meeting the more modest but still very ambitious goal of limiting mean global temperature change to 2 degrees Celsius. 

Finally, we might hold geoengineering in reserve, and use it only if and when 

signs of ‘‘abrupt and catastrophic’’ climate change first emerged. The advantage in 

this proposal is that we would avoid the risks associated with geoengineering until 

the risks of climate change were revealed to be substantial. The disadvantage is 

that, when we finally used geoengineering, we might discover that it does not work 

as expected, or that it cannot prevent the changes taking place at that time. 

Overall, the third and fourth options have merit. I cannot see the case for the first 

and second options.

Implications for R&D

Having now contemplated when we might one day use geoengineering, let me now 

turn to the question of near-term decisions to carry out R&D. 

A ban on R&D would expose the world to serious risks. Suppose we face a situation of ‘‘abrupt and catastrophic’’ climate change, and decide that we must use 

geoengineering, but that, because of the ban put in place previously, we had not 

done any R&D before this time. Then we would deploy the technology without 

knowing whether it would work, or how it would work, or how we could make it 

work better and with fewer side effects. 

R&D can involve computer simulations, examination of the data provided by ‘‘natural, large-scale experiments’’ like volcanic eruptions, and ‘‘small-scale’’ experiments. Ultimately, however, large-scale experiments, undertaken over a sustained 

period of time, would be required to learn more about this technology. If 

such an experiment were done for the purpose of learning how geoengineering 

might be deployed to avoid a future risk of ‘‘abrupt and catastrophic’’ climate 

change, it would resemble using geoengineering along with emission reductions to 

prevent significant climate change. This makes the distinction between R&D and 

deployment somewhat blurred. It also blurs the distinction between the third and 

fourth options discussed above. 

It might be argued that carrying out R&D would hasten the use of the technology. 

That depends on what we discover. We might discover that it doesn’t work, or that 

it has worrying side effects of which we were previously unaware (in addition to the 

worrying side effects of which we were previously aware). This would make us less 

inclined ever to use geoengineering. Alternatively, we might discover that we can 

make it work better, and reduce its side effects. This would make us more inclined 

to use it—but this knowledge should make us more inclined to use it. 

It is very hard to understand how knowing less about this option could possibly 

make us better off.

The geopolitics of geoengineering

Thus far I have considered geoengineering’s role in a climate policy oriented towards reducing global risks. As mentioned in my introduction, this is one of two important perspectives. The second is the perspective of the nation state. 

It is important that we consider the perspective of different states and not only 

our own. Many countries are capable of deploying geoengineering. Over time, more 

and more countries will be capable of deploying geoengineering.
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Risks and incentives

Let us now reconsider all the things that can and should be done to reduce the 

risks associated with climate change, but do so from the perspective of individual 

countries. 

Emission reductions are a global public good. Emissions mix in the atmosphere. 

The benefits of reducing emissions are thus diffused. A country that reduces its own 

emissions receives just a fraction of the global benefit, while paying the full cost. 

There is thus a temptation for countries to ‘‘free ride.’’ In the case of climate change 

this tendency is particularly powerful because the costs of abating one more ton increase as the level of emission reductions increases. Put differently, starting from 

a situation in which every state is cutting its emissions, each state has a strong incentive to save costs by abating less. 

Countries are also interconnected through trade. As one country or small group 

of countries cuts its emissions, ‘‘comparative advantage’’ in greenhouse-intensive 

goods will shift to other countries, causing the emissions of these countries to increase. In addition, as some countries reduce their emissions by reducing their use 

of fossil fuels, the price of these fuels traded internationally will fall, causing other 

countries to increase their consumption and, hence, their emissions. 

Overall, the incentive for countries to cut back their emissions is weak (Barrett 

2005). This explains why international agreements to limit emissions worldwide are 

needed. This also explains why our efforts to develop effective agreements have 

failed. It is really because of this failure that we need to consider geoengineering. 

We also need to undertake R&D into new technologies that can help us to reduce 

emissions at lower costs. However, the returns to this investment in R&D depend 

on the prospects of the knowledge generated being embodied in new technologies 

that are used worldwide to reduce emissions. In other words, the incentives to undertake R&D are derived from the incentives to reduce emissions. Because the latter incentives are weak, the former incentives are weak, which explains why the 

world has done remarkably little to develop the new technologies needed to address 

the threat of climate change fundamentally. 

Adaptation is very different. The benefits of adaptation are almost entirely local. 

The incentives for countries to adapt are very powerful. 

The problem here is that some countries are incapable of adapting. Much adaptation will be done via the market mechanism. The rest of it will mainly involve local 

public goods (dikes being an obvious example). The countries that have failed to develop are the countries that will fail to adapt. 

These countries need our assistance, and we and other rich countries have 

pledged to offer this assistance, most recently in the Copenhagen Accord. But the 

incentives for the assistance to be given are rather weak. Climate change could 

widen existing inequalities. 

The incentives to undertake air capture are mixed. On the one hand, air capture 

can be undertaken unilaterally. In theory, a single country could use this technology 

to stabilize atmospheric concentrations, even if every other country failed to lift a 

finger to help. Air capture is thus very unlike the challenge of getting countries to 

reduce their emissions. However, inexpensive options for air capture are of limited 

scale, while options to remove carbon dioxide from the atmosphere on a large scale 

are expensive (Barrett 2009). The latter options would only be used if the threat 

posed by climate change were considered to be very grave. 

Geoengineering is like air capture. It can be undertaken as a single project. It can 

be done by a single country acting unilaterally, or by a few countries acting 

‘‘minilaterally.’’ It does not require the same scale of cooperation as reducing emissions. But geoengineering is very unlike air capture in other ways. It does not address the root cause of climate change. It does not address the associated problem 

of ocean acidification. Most importantly for purposes of this discussion, 

geoengineering is cheap (Barrett 2008a). The economic threshold for deploying 

geoengineering is a lot lower than the threshold for deploying air capture at a massive scale. 

Because the cost of geoengineering is low, the incentives to deploy geoengineering 

unilaterally or minilaterally are strong. In this sense, geoengineering is akin to adaptation. The difference is that geoengineering undertaken by one country or by a 

coalition of the willing would change the climate for everyone. Depending on the circumstances, this could be a good thing (recall that the incentives for rich countries 

to adapt are powerful, but that their incentives to help the poor to adapt are weak) 

or a bad thing. It is because the incentives for individual countries to use 

geoengineering may be strong, and yet other countries may be adversely affected, 

that geoengineering poses a challenge for governance.
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A scenario of ‘‘gradual’’ climate change

Imagine first a situation in which climate change unfolds gradually. In this scenario, there will be winners and losers over the next few decades, perhaps even for 

longer. (Over a long enough period of time, if climate change were not limited, all 

countries will lose.) 

To be concrete, let us consider estimates of the effects of climate change on agriculture as developed by William Cline (2007). According to this work, India’s agricultural potential could fall 30 percent for a 3° C mean global temperature increase 

by around 2080. Upon doing some back-of-the-envelope calculations, I have found 

that India might suffer a loss valued at around $70 billion in 2080. Estimates of 

the costs of offsetting this amount of warming by geoengineering are generally lower 

than this. Hence, it is at least plausible that India might be tempted to use 

geoengineering in the future. 

To reinforce this point, note that about 70 percent of India’s more than one billion 

people currently live in rural areas. Over time, this percentage will fall, but perhaps 

not by that much. Is it realistic to expect that a democracy will not act to help a 

substantial fraction of its people when doing so is feasible and not very costly? 

Note as well that India has already sent an unmanned spacecraft to the moon. 

It is currently planning a manned mission to the moon. It is certainly within India’s 

technical capability to deploy a geoengineering project. 

It is also within its political capability. In early 2009, a joint German-Indian research team undertook an experiment on ‘‘ocean fertilization’’ in the South Atlantic, 

despite protests by environmentalists. India, it should also be remembered, developed nuclear weapons outside of the Nuclear Nonproliferation Treaty, and tested 

those weapons over the objections of other countries. External pressure for restraint 

may not deter India from deploying geoengineering, should India believe that its national interests are at stake. 

India would also have a moral and quasi-legal case for using geoengineering. The 

Framework Convention on Climate Change says that ‘‘developed countries [need] to 

take immediate action . . . as a first step towards comprehensive response . . ..’’ 

India might argue that developed countries failed to fulfill this duty. It might also 

claim that it lacked any alternative means of protection. India might conceivably assert a need to use geoengineering for reasons of ‘‘self-defense.’’

I am not saying that it is inevitable that India would want to deploy 

geoengineering. I am only saying that, under plausible assumptions, the possibility 

needs to be considered. 

Of course, India may not be the first country to contemplate using geoengineering. 

May other scenarios can be imagined. 

If ‘‘gradual’’ climate change produces winners and losers, then the use of 

geoengineering to reduce the effects of gradual climate change will also produce winners and losers. The winners would join India. They might be willing to provide financial support for India’s geoengineering effort. If a ‘‘coalition of the willing’’ were 

to form, the economics of ‘‘minilateral’’ action would likely strengthen the likelihood 

of geoengineering being deployed. 

The losers of any such geoengineering effort would have very different incentives. 

Cline (2007) finds that, due to gradual climate change, agricultural capacity in 

China, Russia, and the United States would likely increase 6 to 8 percent by around 

2080. Under this scenario, if India, on its own or in concert with others, were to 

deploy geoengineering to protect their economies, other countries may suffer as a 

consequence. 

What might these other countries do? They would certainly voice their objections. 

They might threaten to impose sanctions. They might attempt a countervailing 

geoengineering effort to warm the Earth. They might seek to ‘‘disable’’ India’s 

geoengineering effort by military means. This last possibility is especially worrying, 

given that many of the states mentioned as being affected, whether positively or 

negatively, possess nuclear weapons. 

But it is also for this reason that a military strike is most unlikely. The situation 

I have described here points to a clash in rights-the right of one or more states to 

use geoengineering to avoid losses from climate change versus the right of other 

states not to be harmed by geoengineering. Clashes like this occur all the time. They 

rarely, if ever, lead to military conflict. 

To give an example, there are no general rules for assigning rights to transboundary water resources. An upstream state will assert its right to divert the waters of a shared river for its own purposes, while the downstream state will claim 

its right to an uninterrupted flow of this water. Resolution of such disputes invariably demands mutual concessions. Typically, the parties will seek an ‘‘equitable’’ solution, meaning a sharing of rights. The nature of the bargain that is struck will 
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depend on the context, including the characteristics of the parties. For example, if 

the upstream state is poor and the downstream state rich, the latter state may need 

to pay the upstream state not to divert its waters. By contrast, if the upstream state 

is rich and the downstream state poor, the former may need to compensate the latter. 

Perhaps, then, India will refrain from using geoengineering, or scale back its 

plans, in exchange for other countries offering to help India improve the productivity of its agriculture (taking the climate as given). By contrast, if the United 

States were inclined to use geoengineering first, it seems more likely that there 

would be an expectation that the US should finance investments in other countries, 

to blunt the negative impacts on these countries of its use of geoengineering. In both 

cases, the need for a state to take into account the concerns of other states would 

have a moderating influence.

A scenario of ‘‘abrupt and catastrophic’’ climate change

The situation changes when we peer farther into the future. Over longer periods 

of time, even gradual climate change will be harmful all around—melting of the 

Greenland Ice Sheet, for example, would increase sea level by about seven meters. 

It is hard to see how any country could gain from this degree of sea level rise, even 

if it unfolded, as expected, over a period of many centuries. 

Abrupt climate change is a greater worry. Warming is expected to be especially 

strong in the Arctic region. Should this warming trigger massive releases of carbon 

dioxide and methane, a positive feedback will be unleashed. No country will gain 

from such a climate shock. A collapse of the West Antarctic Ice Sheet, though unlikely, would also have very serious consequences. No country will gain from this 

kind of change either. 

It thus seems likely that the interests of states as regards geoengineering will 

tend to converge over time. Tensions that loom large in a world of gradual climate 

change will evaporate in the longer run and will disappear very quickly should the 

prospect of abrupt, catastrophic climate change appear imminent.

Outlines of a geoengineering regime

Should there be a regime for using, or not using, geoengineering? Currently, no 

such regime exists. There are some agreements and some aspects of custom that 

would be relevant to such a decision (Bodansky 1996). But the situation we are contemplating here is unprecedented. Should a country believe that its national security interests were at stake, it would make decisions largely unrestrained by international law. The absence of a regime essentially allows states to act as they please. 

This means that the United States could act as it pleased, more or less. But it 

also means that Russia and China, India and Brazil, Europe, and Japan, and Indonesia and South Africa could all act as they pleased as well. It is in the interests 

of each county to agree to restrain its own choices in exchange for other countries 

agreeing to restrain theirs. The governance arrangement needed for geoengineering 

is thus one of mutual restraint (Barrett 2007). 

As I have stressed throughout this testimony, geoengineering needs to be considered in the context of all the other things we need to do to limit climate change 

risk. For this reason, international governance arrangements for geoengineering 

should be developed under the Framework Convention on Climate Change. Currently, the focus of the Framework Convention is on limiting atmospheric concentrations of greenhouse gases. It would be better, in my view, if the agreement were 

revised to focus on reducing climate change risk, and on balancing this risk against 

the risks associated with addressing climate change. Every good international agreement is revised and reworked as circumstances change. 

Protocols developed under this convention should address specific collective action 

challenges that serve to reduce risks. There should be many such protocols, even 

as regards reducing emissions (Barrett 2008b). There should also be a protocol for 

geoengineering governance. 

A geoengineering protocol should be open to be signed and ratified by every party 

to the Framework Convention. It is important to underscore that every country is 

entitled to participate in the Framework Convention, and that nearly every country 

in the world is a party to this treaty today (the only non-parties are the Holy See 

and Andorra). This principle of universality is important. Every country will be affected by whatever is decided about geoengineering. Every country should have an 

opportunity to shape this technology’s governance. 

The protocol can be more or less restrictive. As it becomes more restrictive, fewer 

states will consent to participate. An agreement that fails to attract the participation of the geoengineering-capable states would be of little benefit. It will be in 
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every country’s interests that as many geoengineering-capable states as possible 

participate in this agreement. It may not be essential that every geoengineering-capable state participate, but at the very least the agreement should establish normative limits that would restrain the behavior even of non-parties. 

As a general approach, negotiations should focus on what countries can agree on 

rather than on what they cannot agree on. The treaty should enter into force only 

after being ratified by a substantial number of countries. An additional requirement 

may be needed to ensure that the geoengineering-capable states also participate in 

great numbers. Note, however, that as the latter condition for entry into force becomes more restrictive the agreement will essentially hand every such state the 

veto. A consequence may be that the agreement would never enter into force. 

What is it that countries can countries agree on? It is likely that all states will 

agree that every state ought to be obligated to inform all other states of any intention to deploy geoengineering. One reason for this is that deployment would be observable by other states in any event. As well, deployment must be sustained if it 

is to affect the climate. The element of surprise would offer no advantages. 

Negotiations will likely focus on a state’s rights and responsibilities—its right to 

deploy geoengineering to safeguard its own citizens and its responsibility not to 

harm other states. It is in the nature of this technology that the latter outcome 

could not be assured. This is likely to have a restraining influence on the decision 

to deploy. 

Countries may agree that they should cooperate to resolve conflicts. A country declaring an intention to deploy geoengineering may agree to hear opposition to its 

plans (these will be voiced in any event, but an agreement may help to establish 

the basis on which opposition can be expressed). It is unlikely that the 

geoengineering-capable states would be willing to have their hands tied completely. 

It is also unlikely that they would agree to have their freedom of action be determined by a vote. Even if they did agree to this in principle, it would be very hard 

to conceive of a voting rule that would be acceptable to all states. It is, however, 

likely that states would agree to aim to seek a consensus. 

Consensus has powerful advantages. It makes each state take into account the 

collective interests of all states, and the individual interests of every state. It creates 

a presumption in favor of unanimity. At the same time, however, it does not give 

any state the veto. Every state may retain the right to act, should a consensus not 

be possible. But any state contemplating deployment would have to face the consequences of its actions. These consequences would include possible counter measures by other states. 

Rules for R&D will be influenced by the rules for deployment. An agreement to 

cooperate over deployment would reduce any advantages to undertaking R&D secretively. In justifying its decision to deploy, for example, a country would need to 

present evidence that geoengineering would not harm other states. Undertaking 

R&D openly, and collaboratively would favor a shared understanding of this technology’s capabilities and effects. It would promote trust. 

The rules I have sketched here are minimal. The main purpose of the protocol 

would be to provide a restraining influence, a forum for resolving conflicts, and a 

setting in which various risks can be balanced. Returning to the two scenarios outlined previously, in the case where some countries might be in favor of 

geoengineering and some against, the consensus rule would create a space for negotiating conflict resolution. In the case where nearly all countries would favor 

geoengineering, this arrangement would provide the stamp of approval.

References

Barrett, Scott (2009). ‘‘The Coming Global Climate-Technology Revolution,’’Journal 

of Economic Perspectives, 23(2): 53–75.

Barrett, Scott (2008a) ‘‘The Incredible Economics of Geoengineering,’’ Environmental 

and Resource Economics, 39: 45–54.

Barrett, Scott (2008b). ‘‘Climate Treaties and the Imperative of Enforcement,’’ Oxford Review of Economic Policy, 24(2): 239–258.

Barrett, Scott (2007). Why Cooperate?: The Incentive to Supply Global Public Goods. 

Oxford: Oxford University Press.

Barrett, Scott (2005). Environment and Statecraft: The Strategy of Environmental 

Treaty-Making, Oxford: Oxford University Press (paperback edition).

Bodansky, Daniel (1996). ‘‘May We Engineer the Climate?’’ Climatic Change 33: 

309321.

Cline, W. R. (2007). Global Warming and Agriculture: Impact Estimates by Country, 

Washington, DC: Peterson Institute for International Economics.
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Wigley, T.M.L. (2006). ‘‘A Combined Mitigation/Geoengineering Approach to Climate 

Stabilization.’’ Science 314: 452–454. 

BIOGRAPHY FOR SCOTT BARRETT

Scott Barrett is the Lenfest-Earth Institute Professor of Natural Resource Economics at Columbia University in New York City. He is also a research fellow with 

CESifo (Munich), the Beijer Institute (Stockholm), and the Institute of World Economics (Kiel). Until recently, he was a professor at the Johns Hopkins University 

School of Advanced International Studies in Washington, DC. He was previously on 

the faculty of the London Business School, and has also been a visiting scholar at 

Yale. He has advised a number of international organizations on climate change, including the United Nations, the World Bank, the OECD, the European Commission, 

and the International Task Force on Global Public Goods. He was previously a lead 

author of the Intergovernmental Panel on Climate Change and a member of the 

Academic Panel to the Department of Environment in the U.K. He is the author 

of Environment and Statecraft: The Strategy of Environmental Treaty-Making, published in paperback by Oxford University Press in 2005. His most recent book, Why 

Cooperate? The Incentive to Supply Global Public Goods, also published by Oxford 

University Press, will appear in paperback, with a new afterword, in May 2010. His 

research has been awarded the Resources for the Future Dissertation Prize and the 

Erik Kempe Award. He received his Ph.D. in economics from the London School of 

Economics.

DISCUSSION

Chairman GORDON. Thank you, Dr. Barrett. 

I think the concept of trying to find what we can agree upon is, 

unfortunately, unusual around here. We spend too much time on 

what we can’t agree upon. 

I thank all of our witnesses for their testimony. I understand 

that Dr. Barrett and Dr. Long are Co-Members of the Bipartisan 

Policy Centers Initiative. Well, you and we are all part of a pioneering effort here. So, we look forward to your additional information, in this, in the body of evidence, in this early, pioneering effort. 

And I am, now I am going to yield to Mr.—Governor Garamendi 

for any question he might have. 

INITIAL REGULATIONS

Mr. GARAMENDI. Thank you very much. Dr. Barrett, your rules 

are a great place to start. What we need is some forum in which 

to begin the discussion, and setting out the rules of the game. And 

I really urge this committee and Congress, and anybody else to try 

to figure out what that forum would be, to set that down. 

Do you have a suggestion on how that might be accomplished? 

Dr. BARRETT. You need a process to initiate discussion. You 

know, it is a great question, and right now, you know, in the follow-up to Copenhagen, there has been a lot of discussion about that 

process, and whether that process is the problem. And I actually 

don’t think the process, the U.N. process is the problem. I think it 

is our approach to climate change that has been the problem. So, 

I think the diagnosis is very important. 

I think on this issue, because all countries have a stake in the 

issue, and I think this is an issue that people need some time to 

think about. You know, our first reactions to this issue were not 

the same as our reactions as we think about it more. 

So, I think the natural place in which there should be the beginning of a discussion would be under the United Nations Framework Convention on Climate Change [UNFCCC]. I think that 
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agreement needs to be revised to address this fundamental problem 

of reducing risk, and once we look at this as a problem of reducing 

risk, we will want to, you know, conclude under that agreement a 

lot of different issues, including geoengineering. 

A POTENTIAL ROLE FOR DOE AND NATIONAL LABS

Mr. GARAMENDI. I don’t have time with my questions to go to 

each one of you about that, but I think that is really a central piece 

of where we need to go as a committee is to, okay, what is the next 

step, what is the process for that. 

I wanted to—I would like to go to Dr. Long for a couple of reasons. One, we have had wonderful discussions about this over the 

years, and you are from my district. So, the other three please excuse me. And this really speaks to Dr. Morgan’s point that the Department of Energy should not have a role here. I disagree with 

that, and I would like Dr. Long to really talk to this issue. 

It turns out that the national laboratories, the Department of 

Energy labs, have a very, I think, wrongly defined mission at the 

moment, which is nuclear security, and I think they should have 

to have a change in their mission statement to one of national security, where all of the resources at those labs can be used to deal 

with a broader range of national security issues, non-bombs. 

For example, the biggest and perhaps the best computer to deal 

with climate modeling is at Lawrence Livermore National Laboratories. Sometimes, Los Alamos will dispute that, and others will 

dispute it, but the labs do have extraordinary computing capability, 

which is central to this issue. And also, a lot of knowledge about 

things that go boom. For example, if you want to seed the atmosphere with sulfates, you are probably going to use something that 

goes boom. 

Anyway, these kinds of things are there, and I would just recommend that. 

So, Dr. Long, if you could speak about the assets that are at the 

laboratories, in the context of dealing with this issue? 

Dr. LONG. Well, I think one of the most important things that 

is in my written testimony, and I didn’t get a chance to talk about, 

is the need for adaptive management in this problem. 

And to do adaptive management, we are going to have to be able 

to predict, we are going to have to make a prediction about the result of our actions, and then, we are going to have to be able to 

discern whether that prediction is correct, by making observations. 

And then, we are going to have to decide whether we are going in 

the right direction, and change direction if we are not. 

There are many things that are required to do that. One of them 

is computing, and one of them is simulation of the climate. The laboratory conducts, currently, a program called PCMDI, which is program and model comparison for climate. These kinds of studies 

that provide very careful, even-handed assessments of whether the 

climate is changing in response to the actions we are taking, or it 

is just climate variability that we are seeing, are going to be critical. and These kinds of calculations are very demanding, and can 

be done at national laboratories. 

But also, this problem, though, also relates to something that Dr. 

Barrett said. Somewhere in here, we have to engage with the pub-
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lic and with the policymakers at the same time that this kind of 

analysis is coming in, because the hardest piece is, as hard as it 

is to make a decision to take an action, we are also going to have 

to make decisions to change the direction of our action, and that 

is going to have to be supported hand in hand with really good 

analysis and fingerprinting of what we are actually doing. And that 

exists at the National Laboratories. 

Mr. GARAMENDI. Dr. Morgan, do you want to jump in in the remaining seconds, do so. 

Dr. MORGAN. One activity that is going forward, the Royal Society, as we heard in the first session, has just undertaken something called the Solar Radiation Management Governance Initiative, which will be undertaken by the Royal Society, the science societies of the developing world, by Environmental Defense Fund, 

the NGO, and a number of other organizations, including, for example, the International Risk Governance Council, whose Scientific 

and Technical Council I chair, and which convened one of the two 

workshops that I mentioned. 

So, that is a process, an international process that is ongoing. I 

would argue that one does not want to get too firm a restriction 

in place on small scale studies early on, because it will tie the 

science’s hands. 

Mr. GARAMENDI. Well, you were very quick on—when the red 

light came on, right in the middle of a sentence. I don’t know if the 

Chairman is that strict. Could you finish your sentence? 

Dr. MORGAN. No, I was simply—I mean, the reason I showed 

that slide with the funny box was to simply say, I think what the 

science community ought to be trying to do is say, you do small 

scale stuff inside this space, and it is a scientific question what 

that space ought to be. There shouldn’t be a lot of oversight and 

restriction. If you put too much U.N. approval and other stuff in 

place, we are never going to get any answers. 

And so, we have got to find a space that is safe and appropriate 

to do studies, and then say, outside that, that is forbidden until, 

you know, there is some larger governance structure in place. 

Mr. GARAMENDI. Mr. Chairman, I am going to take another 30 

seconds if I might, and just compliment you on this meeting, and 

really urge you and your committee staff and the rest of us, to really hone in on this issue. 

I am very taken by the issue of setting the rules, whatever those 

might be, and the caution that was given, and also, the full utilization of all of our research capabilities here in the United States and 

around the world, in some sort of a coordinated effort. It is really, 

really important in my mind, and I thank you for the hearing. 

Chairman GORDON. Thank you, Governor. The lights are automatic, but folks have made a lot of effort to get here and participate, so we try to be generous with our time. 

Mr. Hall is recognized. 

Mr. HALL. Mr. Chairman, I only want to ask unanimous consent 

to do something here, if I can find it. I want to, a paper that was 

published in the Journal of Petroleum Science and Engineering, by 

the Economides couple. I would like unanimous consent to place 

that journal article into the record. 

Chairman GORDON. Without objection. 
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Mr. HALL. I yield back my time, sir. 

Chairman GORDON. Dr. Baird is recognized. 

THE PROSPECT OF UNILATERAL GEOENGINEERING

Mr. BAIRD. I thank the Chair. I thank our witnesses. I find this 

one of the most fascinating things we are dealing with, because you 

have got as consequential a situation as you can imagine, and a 

system more complex than anything else on Earth, because it is 

Earth, and lots of unintended consequence risks. 

In just the last week, or this week, I read an article about fertilization of the oceans leading to excessive algal blooms, presumably, and domoic acid. And the question here is, we are doing 
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geoengineering. It is called the CO2 we are putting into the atmosphere, and the methane, et cetera. And now, we are trying to sort 

of put that genie back in the bottle. 

Let us suppose I am on the Maldive Islands, and I quite fairly 

and realistically assume that the likelihood of the industrialized 

world actually cutting CO2 emissions in a reasonable time is grim, 

and it is existential for us, and I am going to just do some SRM 

on our own. You can’t hardly fault them. We have done 

geoengineering in the other direction on our own. What is to prevent that, or even in a James Bond scenario, some rogue rich guy 

puts some airplanes in the air and seeds the clouds? What is to 

prevent that? Dr. Morgan, or Dr. Rusco, you please talk about that. 

Dr. MORGAN. Nothing to prevent somebody initiating it, but the 

U.S. Navy can stop the Maldives. The U.S. Navy can’t stop, you 

know, Russia, if it decides that the whole interior of the country 

has become an impermeable bog, because of the thawing of permafrost, China, because precipitation patterns have changed and they 

can’t feed their people anymore. 

So, one of the reasons that we initiated this workshop at the 

Council on Foreign Relations a couple of years ago was precisely 

to begin to address the issue of unilateral action of the sort you 

have described, and I think it remains a serious concern. There is 

disagreement within the foreign policy community about just how 

big a concern unilateral activity might be, but the notion that one 

or a couple of major states might decide to do it, I think, is quite 

troubling, and given the right circumstances, might be very hard 

to do much about. 

Mr. BAIRD. And a new variation on mutually assured destruction. 

Yeah, Dr. Barrett. 

Dr. BARRETT. It is a great question. I think an important, and 

actually, there is a scenario I developed in my written testimony 

about India. That would be much more likely, to be the country to 

use it. It is only a hypothetical, but still, it is very plausible, given 

the impact on their population. 

Mr. BAIRD. Yes, indeed. 

Dr. BARRETT. And the migration that would be forced by it, sure. 

Yes, indeed. And, but other countries, again, that scenario of graduated climate change. If India had the incentive to want to use 

geoengineering, other countries would be adversely affected. They, 

of course, would oppose that move, and you can imagine, first, opposition would be voiced, then other measures might be taken. 

There might be a development of counter-geoengineering measures, 

and also, there could be a military strike. It is precisely because 

of that, actually, I think what you are looking for, and I think what 

we want in the form of, what I call ‘‘rules.’’ Or in terms of a kind 

of regime on geoengineering, a space in which countries can actually negotiate through their differences. 

And I think there will be strong incentives to do that. The countries that are the most capable to act on geoengineering are all nuclear-capable states, and I think the most important thing is that 

we don’t let this whole system rift, but we create the space for negotiation. 

Mr. BAIRD. Dr. Long. 
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Dr. LONG. I would like to add to that that I think that the research program can help to mitigate the situation. The thing that 

we need to focus on is the creation of international norms and 

mores that support the same ethical constructs when it comes to 

deploying geoengineering, and by building that in to an international research program, and beginning to practice those kinds 

of relationships and norm-building exercises through the research 

program, I think we can help to mitigate that situation. 

THE NATIONAL SECURITY AND GEOPOLITICAL IMPACTS OF

CLIMATE CHANGE

Mr. BAIRD. I would really encourage this panel and my colleagues on the other side of the aisle to, I think there is an urgent 

need for a constructive dialogue with my friends on the other side 

of the aisle on this, because we spend an inordinate amount of time 

here, on this committee, unfortunately, debating whether or not 

this is real, as if the outcome of our debate will somehow impact 

what happens in the real world. 

By that, I mean, as if climate change is going to be stopped if 

we declare it is not happening. But I think the adverse consequences that you are describing, the profound geopolitical, national security, economic disruption if you get your bet wrong, really has to be discussed. Because if we are at this level of discussion, 

and when you talk about India, the migratory disruption of coastal 

sea rises, it is astonishing, and how that affects everything else. 

You really have to engage my friends on the other side, who have 

a good and healthy decent respect for national security and economic issues, to consider this aspect, and we haven’t done it 

enough, and I would invite them to discuss with you folks these implications. Because if we just say well, we are not going to do anything, because climate change is a hoax, as is sometimes said by 

colleagues, that hoax can have some darn serious consequences if 

it is not a hoax. 

And we just need to speak in the language of my friends on the 

Republican side, I think, will appreciate, in terms of national security, et cetera, and so, I hope—I am sorry they are not here, but 

I think it is an avenue that we ought to explore more. 

Thank you, Mr. Chairman, for calling this hearing. 

Chairman GORDON. Thank you, Dr. Baird. We will be sure to 

have metal detectors when we get ready to do that discussion. 

THE ROLE FOR FEDERAL AGENCIES

Let me conclude here, unless Mr. Hall has some additional suggestions, there have been discussions about federal research. 

Could, I would ask the panel in general, what different agencies 

would be the, what agency or agencies would be the appropriate vehicles for this type of research, and we will just start and go down. 

Dr. RUSCO. Thank you. We are in the process of engaging all the 

agencies that might have a role to play in this, and we will be reporting on that soon to the Committee. 

Chairman GORDON. Will you speak something like the National 

Nanotechnology Initiative, where there would be a coordinated effort across a variety of different agencies? 
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Dr. RUSCO. I think that our past work points to a need for a coordinated effort on anything of this magnitude. There, you want to 

avoid unnecessary duplicative activities, but you also want to utilize all the many resources and assets that the Federal agencies 

bring to this sort of an effort. And so, a coordinated effort that 

looks at the costs and benefits of a national strategy for looking at 

this sort of research is what is needed. 

Chairman GORDON. We are being called for votes, so let me just 

ask, I would assume everyone concurs with that, unless you have 

a suggestion of something specific. Otherwise, is there anyone that 

has anything else? Yes, Dr. Long. 

Dr. LONG. In carbon remediation, on the carbon remediation side, 

we already, as I mentioned, we already run a CCS program that 

could be easily expanded. EPA should probably be involved in that. 

On the climate intervention technologies, many of them are related 

strongly to Climate Science Program, and much of it, particularly 

the observation network and the ability to predict what is going to 

happen when you make an intervention, that is, as an expansion 

of climate science, DOE, NASA, NSF, are all involved, and should 

be probably involved in that. 

Dr. MORGAN. And my testimony speaks specifically to your question, so I won’t. 

Dr. BARRETT. Briefly. First, I would not have the Department of 

Defense, and second, I would encourage international collaboration. 

Chairman GORDON. And you want to elaborate on why you would 

not have the Department of Defense participate? 

Dr. MORGAN. I think this issue of trust that I ended my testimony on, is extremely important, and I think the moment that, and 

if our Defense Department can be involved, then so can other countries, and I think there is already enough distrust on a number of 

issues, including, for example, space, involving different countries. 

And I think it could be much better to keep this as an issue that 

is addressing just the one threat. 

Dr. BARRETT. Both of the international workshops reached much 

that same conclusion. 

Dr. LONG. Thank you. And I would take it one step further, 

which is to say that our national programs should explicitly look 

at research that would enhance the global welfare, rather than the 

national welfare. 

Mr. BAIRD. Mr. Chairman. 

Chairman GORDON. Dr. Baird is recognized. 

Mr. BAIRD. Would you not, however, think it is beneficial for the 

Department of Defense to at least inform the debate by this body 

about the consequences if we fail to address this? They may not be 

involved in structuring the global regulatory environment, but they 

certainly ought to be involved in gaming out the consequences for 

their responsibilities. Would that make sense? 

Dr. BARRETT. I think they already are, in terms of what would 

happen, in terms of migration of peoples and that sort of thing. 

Mr. BAIRD. They certainly are. Just—that point I made earlier. 

I want—— Dr. BARRETT. You give some credibility. 

Chairman GORDON. As I said, we, our votes are on their way 

right now, so let me thank all of our witnesses for being here 
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today. The record will remain open for two weeks for additional 

statements from Members, and for answers to any follow-up questions this committee may ask the witnesses. 

Once again, I appreciate you giving you information to this pioneering body of information, that I think will be beneficial for generations to come. 

And this hearing is concluded, and the witnesses are excused. 

[Whereupon, at 1:23 p.m., the Committee was adjourned.] 
(335)

Appendix 1: 

ANSWERS TO POST-HEARING QUESTIONS
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1The Royal Society, Geoengineering and the climate: science, governance and uncertainty (London: September 2009). 2 National Academy of Sciences, Policy Implications of Greenhouse Warming: Mitgadon, Adaptation, and the Science Base (Washington, D.C.: 1992). 3 As we testified, the Royal Society noted that large-scale deployment of some CDR approaches 

such as widespread afforestation—planting of forests on lands that historically have not been 

forested—or methods requiring substantial mineral extraction—including land or ocean-based 

enhanced weathering-may have unintended and significant impacts within and beyond national 

borders.

ANSWERS TO POST-HEARING QUESTIONS

Responses by Frank Rusco, Director of Natural Resources and Environment, Government Accountability Office (GAO)

Questions submitted by Chairman Bart Gordon

Q1. Geoengineering is an emerging field, and as such, it does not have a standard, 

widely agreed upon definition.

Q1,1a. How is geoengineering being defined today?

A1,1a. Our work to date indicates that scientists, policy experts, and major research 

bodies have not yet agreed on the definition of geoengineering. Our testimony uses 

the relatively broad definition of geoengineering—deliberate large-scale interventions to diminish climate change and its impacts—used by the United Kingdom’s 

Royal Society in its September 2009 geoengineering report, which classified 

geoengineering approaches into two major categories: solar radiation management 

(SRM) and carbon dioxide removal (CDR).1 The National Academy of Sciences used 

a similarly broad definition of geoengineering in its 1992 report on the policy implications of greenhouse warming.2 However, some policy experts have published articles that apply a relatively narrow definition of geoengineering that only includes 

SRM approaches. Most recently, the scientific organizing committee of the March 

2010 Asilomar International Conference on Climate Intervention Technologies released a statement reclassifying geoengineering approaches into two groups—climate intervention methods (SRM) and climate remediation methods (CDR). 

Q1,1b. Discuss the pros and eons of the existing definitions.

A1,1b. We have not formally evaluated the advantages and disadvantages of the existing definitions for geoengineering as part of our work to date and, as a result, 

do not have an opinion on this issue. However, as we have testified, the experts we 

spoke with stated that there are different policy implications associated with pursuing SRM compared to most CDR approaches. Consequently, the definition policymakers chose when deciding whether to pursue geoengineering as part of a broader 

response to climate change would affect which policy issues and research needs a 

federal geoengineering strategy would have to address. For instance, we testified 

that some experts consider certain SRM approaches to be relatively inexpensive to 

implement and generally hold greater potential for causing uneven environmental 

impacts-such as changes in precipitation beyond national or regional boundaries. 

Thus, these approaches risk undesirable economic, ethical, legal, and political implications that would need to be addressed prior to deploying any of these technologies. 

In contrast, some experts noted that most CDR approaches-with the exception of 

ocean-based strategies such as fertilization-would have limited impacts across national boundaries and could, therefore, mostly involve discussions with domestic 

stakeholders.3

Q1,1c. Lastly, how should geoengineering be defined going forward?

A1,1c. Because we have not formally evaluated the pros and cons of different definitions, we do not have a position on the appropriate definition for geoengineering. 

However, other scientific and policy organizations will be providing their perspectives on geoengineering later this year, which may provide additional insight on this 

issue. For example, the National Academy of Sciences will be including 

geoengineering as part of its America’s Climate Choices review for the Congress, 

which is scheduled for release this year. Additionally, the National Commission on 

Energy Policy has indicated that it has plans to explore the definition of 

geoengineering as part of its project due later this year. Finally, the scientific organizing committee of the Asilomar International Conference on Climate Intervention 

Technologies expects to issue a report this year on the conference’s proceedings, 

which may include potential geoengineering research principles based on the discussions among participating scientific and policy experts.
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Q2. Which federal research agencies or programs, as well as which nonfederal institutions, such as universities, have the capacity to contribute to potential 

geoengineering research programs?

A2. We have not specifically examined the capacity of federal agencies, programs, 

and universities to contribute to geoengineering research. However, we testified that 

some federal agencies, such as the Department of Energy, the National Science 

Foundation, and the National Aeronautics and Space Administration, among others, 

have already sponsored or conducted some research related to geoengineering. Furthermore, as we testified, federal officials stated that ongoing federal research and 

observations on basic climate change and earth science conducted by, for example, 

agencies participating in the U.S. Global Change Research Program (USGCRP), 

could be relevant to improving understanding about proposed geoengineering approaches and their potential impacts. Additionally, our interviews with experts to 

date indicate that a federal geoengineering research program should be an interdisciplinary effort across multiple agencies, although experts differed as to which 

agencies should be involved in such a program. We plan to provide further information on existing federal geoengineering efforts in our report to be issued later this 

year.

Q3. Which agencies or programs should not be involved? Why?

A3. We do not have a position on which agencies should or should not be involved 

in a federal geoengineering research program. As indicated in our response to question 1b; how narrowly or broadly geoengineering is defined could have implications 

for the design of a federal research program and for the decision on which agencies 

would participate.

Questions submitted by Representative Ralph M. Hall

Q1. There are several basic questions, about the governance of geoengineering that 

need to be explored before delving into this research. On the international side:

Q1,1a. If we were to enter into an international agreement to explore cooperative research efforts into geoengineering, which countries would necessarily need to 

be included?

A1,1a. This is an important question and is worthy of study. However, an analysis 

of which countries would need to be included in an international agreement to explore geoengineering research is beyond the scope of our ongoing work.

Q1,1b. Do you envision such an agreement facing resistance similar to previous attempts at global agreements addressing climate change?

A1,1b. We have not examined whether an international agreement to explore cooperative research would face resistance similar to previous climate change agreements. However, in our testimony we noted that legal experts we interviewed 

agreed that the governance of geoengineering research should be separated from the 

governance of deployment. These legal experts agreed that some type of regulation 

for geoengineering field experiments was necessary, but they differed on whether 

there should be a comprehensive international governance regime under the auspices of a treaty such as the United Nations Framework Convention on Climate 

Change, or whether other existing international agreements could be adapted and 

used to address specific geoengineering approaches that fall within their purview. 

Regarding deployment, we testified that some scientific and policy experts we interviewed noted that establishing a governance regime over geoengineering deployment 

for certain approaches may be as challenging as achieving international consensus 

on carbon mitigation strategies. This issue is challenging because of questions about 

whether deployment is warranted, how to determine an appropriate new environmental equilibrium, and what compensation should be offered for adverse impacts, 

among other issues.

Q1,1c. Should we be looking at this issue as a national security problem, not unlike 

a rogue state or terrorist group that releases a biological, chemical or nuclear 

weapon on some unsuspecting populace?

A1,1c. We do not have a position on whether the Congress should be looking at 

geoengineering as a national security problem. However, we testified that, according 

to the experts we spoke with, the potential uneven distribution of environmental 

and economic impacts associated with some geoengineering approaches, particularly 

SRM, may create relative winners and losers which would sow conflict among nations. As we also testified, several experts we spoke with stated that since some 
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SRM approaches are considered to be relatively inexpensive to implement, one nation, group, or individual could decide to unilaterally deploy one of these technologies. These experts stated that it is important to begin studying how the United 

States or the international community might respond to the unilateral deployment 

of a SRM technology that resulted in gains for some nations and losses for others.

Q1,1d. Could the actions of a lone ‘‘climate savior’’ have global effects that would 

rise to this level of concern? Or is the technology really not in place where 

this is an issue now? Should we be discussing it for the future?

A1,1d. As we noted in our response to your question 1c, we testified that some SRM 

approaches would be relatively inexpensive to implement and that a nation, group, 

or individual could decide to unilaterally deploy one of these technologies. Additionally, some experts we spoke with said that it would be possible to deploy some form 

of SRM, such as stratospheric aerosol injection, using current technology. Furthermore, as we testified, several experts stated that it is important to begin studying 

how the United States or the international community might respond to the unilateral deployment of a SRM technology that resulted in gains for some nations and 

losses for others.

On the domestic side:

Q1,1e. There are several existing federal laws that could cover some, but not all, aspects of geoengineering. What are the specific gaps in the domestic federal 

framework that would be needed for us to move forward with this? How much 

would such a regulatory structure cost to implement?

A1,1e. In our statement, we identified several domestic regulatory gaps. For instance, while EPA plans to issue a final rule governing underground injection of carbon dioxide for geological sequestration under the Safe Drinking Water Act, EPA 

officials noted that this rulemaking was not intended to resolve questions concerning how other environmental statutes might apply to injected carbon dioxide. 

Additionally, EPA officials noted that while the agency has the authority to regulate 

some ocean fertilization activities under the Marine Protection, Research and Sanctuaries Act of 1972, the law only applied under certain conditions. Consequently, a 

domestic company could conduct ocean fertilization—introducing nutrients to promote phytoplankton growth and enhance biological storage of carbon—outside of 

EPA’s regulatory jurisdiction and control if, for example, the company’s fertilization 

activities took place outside U.S. territorial waters, which extend 12 miles from the 

shoreline or coastal baseline, from a foreign-registered ship that embarked from a 

foreign port. 

We will continue our work related to the views federal officials and experts have 

on how existing domestic laws and international agreements may apply to 

geoengineering. We expect to include additional detail on these issues in our final 

report to be completed later this year. While the costs for implementing a regulatory 

structure for geoengineering is certainly an important consideration for any future 

policy development and is worthy of study, such an analysis is beyond the scope of 

our current effort.

Q1,1f. Would the decision to deploy such a technology be appropriate for government 

only? Or, if there is private sector investment and work in this area, should 

they have a say in the decision? Are there any safeguards for the private sector 

to prevent the government from deploying such a technology?

A1,1f. We do not have a position on the level of involvement that the private sector 

should have in the decision to deploy any geoengineering approach, and this issue 

is beyond the scope of our work to date. Similarly, we have not examined the private 

sector’s ability to prevent the government’s deployment of a given geoengineering 

technology, and we will not be addressing this issue in our final report.

Q1,1g. Would the domestic decision to deploy a geoengineering technology be similar 

to the Presidential decision-making power to use nuclear weapons? Or, would 

this type of deployment benefit from the input of the Congressional and Judicial branches of government?

A1,1g. We have not studied the dynamics of federal decision-making concerning the 

deployment of any geoengineering technology and doing so is beyond the scope of 

our ongoing work.

Q1,1h. If we were to deploy such a technology, and it did not work as expected, 

where would the liability for the unintended consequences lie? With those 

who developed the technology, or with those who decided to use it?
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4The Royal Society, Geoengineering arid the climate: science, governance and uncertainty. 5GAO, Climate Change: Federal Actions Will GreatlyAffect the Viability of Carbon Capture 

and Storage as a Key Mitigation Option, GAO–08–1080 (Washington, D. C.: Sept. 30, 2008).

A1,1h. Liability for unintended consequences from geoengineering is an important 

and complex governance issue that would require a detailed analysis. Specifically, 

the Royal Society report on geoengineering identified liability as a key governance 

issue that should be evaluated prior to any large-scale experimentation or implementation of a particular geoengineering approach.4 Additionally, our prior work on 

carbon capture and storage discussed stakeholder concerns regarding liability for 

stored carbon dioxide in underground formations, which could be relevant to some 

CDR approaches.5 Although conducting a detailed analysis of liability issues is beyond the scope of our ongoing work, we expect to provide some context for this issue 

in our final report based on our review of relevant literature. 

Q2. Several months ago, a paper was published in the Journal of Petroleum Science 

and Engineering titled, ‘‘Sequestering carbon dioxide in a close underground volume.’’ The authors of this study, Christine Ehlig-Economides and Michael J. 

Economides, suggest that ‘‘underground carbon dioxide sequestration via bulk

CO2 injection is not feasible at any cost,’’ since the CO2 would require up to 500 

times more space underground than the carbon did when it was bound as coal, 

oil or natural gas.

Q2,2a. If this hypothesis is correct, how would this affect your estimation on the feasibility of geoengineering as a viable option from a technological and a cost 

effectiveness point of view?

A2,2a. We have not evaluated the feasibility of geoengineering approaches from a 

technological or cost-effectiveness perspective as part of our work to date. As we testified, substantial uncertainties remain regarding the efficacy and potential environmental effects of proposed geoengineering approaches, and additional research 

would be needed before a proper assessment of feasibility or cost effectiveness could 

be conducted However, should the government choose to move forward with 

geoengineering research, we have reported that a comprehensive assessment of costs 

and benefits that includes all relevant risks and uncertainties is a key component 

in strategic planning for technology-based research programs. We do not expect to 

report on the feasibility or cost-effectiveness of the various technological options for 

geoengineering as part of our final report. However, we are conducting a 

geoengineering technology assessment for the Committee, which will address technological feasibility in greater detail.

Q2b. How would such a hypothesis alter the debate that is currently ongoing about 

the need to mitigate climate change through reducing emissions?

A2b. We have not evaluated how such a hypothesis might alter the debate that is 

ongoing about the need to mitigate climate change through reducing emissions as 

part of our work to date, and this is beyond the scope of our ongoing work.

Q3. During your research into this topic, were there any discussions surrounding liability? For example, if one nation were to act using a stratospheric aerosol 

method, and several nations gained from the resultant ‘‘cooling’’, what if there 

were unintended negative impacts. Could each nation be liable in some way, or 

just the one nation taking the action? How would the liability or remediation 

be shared?

A3. See our response to your question 1h, above.

Q4. In your testimony, you list several Executive Branch agencies that currently enforce laws that would partially cover geoengineering research and deployment. 

The Environmental Protection Agency is the primary agency. Would you advocate that EPA take the primary role in developing a federal regulatory structure 

for the research and deployment of geoengineering technologies? Are they the 

most qualified? Are there any other areas of research like this in which EPA, 

which is first and foremost a regulatory and not a research agency, takes the 

lead Federal role?

A4. We do not have a position on whether EPA should take the primary role, or 

whether EPA is the most qualified agency to develop a federal regulatory structure 

for geoengineering research and deployment. Additionally, we have not examined 

whether there are other research areas where EPA has taken the lead federal role 

as part of our work to date. However, as we testified, while staff from federal offices 

coordinating the U.S. response to climate change—the President’s Council on Envi-
340

ronmental Quality (CEQ), the Office of Science and Technology Policy (OTSP), and 

the USGCRP—stated that they do not currently have a geoengineering strategy or 

position, several experts we interviewed stated that geoengineering research should 

be led by a multiagency coordinating body, such as OSTP or USGCRP. Furthermore, 

we testified that the White House recently established an interagency task force on 

carbon capture and storage (CCS)—which will report to CEQ—to propose a plan to 

overcome the barriers to widespread CCS deployment, and that the plan will address, among other issues, legal barriers to deployment and identify areas where additional statutory authority may be necessary. This task force was not specifically 

established to address regulatory barriers for geoengineering approaches; however, 

the legal and regulatory issues surrounding underground storage of carbon dioxide 

could apply to some CDR approaches. Additionally, we will continue to collect federal officials’ and experts’ views related to how existing domestic laws and international agreements are being applied to geoengineering and expect to include further detail on these issues in our final report.
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ANSWERS TO POST-HEARING QUESTIONS

Responses by Scott Barrett, Lenfest Professor of Natural Resource Economics, School 

of International and Public Affairs and the Earth Institute at Columbia University

Questions submitted by Chairman Bart Gordon

Q1. How is geoengineering being defined today? Discuss pros and cons of existing 

definitions. How should geoengineering be defined going forward?

A1. There is no standard definition today. I think this is not important. It is, however, important that people define the term before using it. 

In my opinion, the best definition is the one given in my written testimony; actions taken deliberately to alter the temperature without changing the atmospheric 

concentration of greenhouse gases. Importantly, by this definition, ‘‘solar radiation 

management’’ is geoengineering. ‘‘Carbon Dioxide Removal’’ is not. These two approaches really need to be distinguished because they are very different The former 

can act quickly, but does not address the problem fundamentally. The latter addresses the problem fundamentally, but is slow and expensive. 

As our understanding of the technological possibilities improves, we’ll start to 

focus on particular ideas. My guess is that, by the time we deploy geoengineering, 

should that time ever come, we will use a different approach from the ones being 

discussed today. It is because of this that I focused my written testimony on 

‘‘geoengineering’’ as a generic intervention.

Q2. Which Federal agencies, as well as non-Federal institutions, have capacity to 

contribute to geoengineering research? Which should not be involved?

A2. I think the most important thing is that any research be done in the context 

of an international framework. The reason is that, if we are thinking of possibly 

doing geoengineering research, other countries will be thinking the same thing. 

Given the implications of deploying geoengineering, and the problem in distinguishing research from deployment, it is best that this be done under a governance 

arrangement. 

For similar reasons, I think it would be best for research to be done in a collaborative way with other countries. It is essential that this process build trust. 

We should not only do research on geoengineering itself but on the consequences 

of deployment—for agriculture, terrestrial ecosystems, the oceans, and so on, and 

for other countries and parts of the world as well as for the United States. 

Many agencies and non-federal institutions could play a part. I think it is important that the Department of Defense not undertake research into geoengineering. 

If this technology is ever to be used, it must be used for peaceful purposes, and our 

research initiatives must make that pledge credible.

Questions submitted by Representative Ralph M. Hall 

Q1. There are several basic questions about the governance of geoengineering that 

need to be explored before delving into this research. On the international side:

a. If we were to enter into an international agreement to explore cooperative research efforts into geoengineering, which countries would need to be included?

b. Do you envision such an agreement facing resistance similar to previous attempts at global agreements addressing climate change?

c. How would a global partnership be structured?

d. Would certain countries be required to provide more resources than others? 

If a country provided more resources, would they have more decision-making 

authority or more input?

e. Should we be looking at this issue as a national security problem, not unlike 

a rogue state or terrorist group that releases a biological, chemical or nuclear 

weapon on some unsuspecting populace?

f. Could the actions of a lone‘‘climate savior’’ have global effects that would rise 

to this level of concern? Or is the technology really not in a place where this 

is an issue now? Should we be discussing it for the future?

On the domestic side:

g. Would the decision to deploy such a technology be appropriate for government 

only? Or, if there is private sector investment and work in this area, should 
342

they have a say in the decision? Are there any safeguards for the private sector to prevent the government from deploying such a technology?

h. If we were to deploy such a technology; and it did not work as expected, where 

would the liability for the unintended consequences lie? With those who developed the technology, or with those who decided to use it?

A1. Governance-note that, unless stated otherwise, I am taking ‘‘geoengineering’’ 

here to mean actions taken deliberately to alter the temperature without changing 

the atmospheric concentration of greenhouse gases. This creates a novel challenge 

for governance. ‘‘Air capture’’ and storage of carbon dioxide is also important, and 

addressed below, but this technology poses a very different challenge for governance.

International

a. Since every country will be affected by the deployment of geoengineering, and 

since research would be undertaken with a view, possibly, to deployment, the international governance arrangements should be open to all countries. My view is that 

these arrangements should be expressed as a protocol under the Framework Convention on Climate Change, in which case participation would be open to every 

country that is a party to this Convention (virtually every country in the world is 

already a party to this agreement). Note that the Framework Convention should be 

revised to stress the importance of reducing risks. Note also that countries may also 

wish to negotiate collaborative agreements about specific research initiatives. These 

would only need to involve the participation of the states involved—perhaps a small 

number of states. The important thing is that these ‘‘minilateral’’ agreements on research be undertaken in accordance with the very broad governance arrangement 

noted above.

b. I do not believe that there will be resistance to negotiating such a protocol. Getting countries to reduce emissions is the hardest of all global collective action problems, and so we shouldn’t be surprised that we have found this difficult to do. Getting countries to agree on basic rules for geoengineering governance is very different. International negotiations are never easy, but these negotiations will be easi- er than negotiations on limiting emissions.

c. I would recommend that the protocol aim to spell out very broad principles. The 

focus should be on what countries can agree on rather than on what they cannot 

agree on. These, I think, should be the main points: (1) that the protocol be open 

to every party to the Framework Convention to sign and ratify; (2) that the agreement enter into force after being ratified by a substantial number of countries, including a significant number of ‘‘geoengineering-capable’’ states; (3) that every party 

be obligated to inform all other parties of an intention to deploy geoengineering, including any ‘‘field testing’’; (4) that deployment be undertaken for peaceful purposes 

and for purposes that contribute to meeting the objectives of the Convention (which, 

as I mentioned above, should be revised to stress the importance of reducing risk); 

(5) that every party be obligated to cooperate to resolve any possible conflicts; (6) 

that agreements to resolve conflict be made as far as possible by consensus; and (7) 

that R&D be done openly, and preferably collaboratively, and subject to monitoring/

verification. Transparency builds trust.

d. As noted above, agreements to collaborate in doing R&D may involve a small 

number of states. There are many ways to share the burden of financing. We have 

many precedents, such as the ITER project, CERN, and the International Space Station. A very simple way to allocate this burden is by reference to the UN scale of 

assessments. As regards decision-making authority, the agreement should be under 

the protocol I noted above, which sets the parameters, as it were, for international 

governance. Subject to this, the principle that is almost certain to be applied is ‘‘no 

representation without taxation.’’

e. I think the deployment of geoengineering outside of the international framework 

noted above would be perceived as constituting a possible threat to the security-of 

other states. Geoengineering should only be undertaken for peaceful purposes, and 

by agreement-by consensus as far as possible.

f. Any geoengineering undertaken outside of the international framework noted 

above should be discouraged, and considered as lacking international legitimacy. 

Any such effort would thus be vulnerable to intervention, discouraging investment 

in the first place.

Domestic:

g. Under the above international framework, the state deploying geoengineering 

would be responsible for its consequences, whether that deployment were done by 

the government or another entity under its control (as in within its territory). 
343

Whether the private sector were involved or had any say would be up to individual 

states, but the state deploying geoengineering would be responsible for the consequences, under the international framework outlined above. Any safeguards for 

the private sector would need to be provided by domestic law.

h. Liability would be extremely difficult to determine, which is why it is essential 

that the decision to deploy be based on consensus insofar as possible. Domestically, 

risk sharing would likely be a public decision (much like third party liability for nuclear power accidents).

Q2. Several months ago, a paper was published in the Journal of Petroleum Science 

and Engineering titled,‘‘Sequestering carbon dioxide in a close underground volume’’ The authors of this study, Christine Ehlig-Economides and Michael J. 

Economides suggest that ‘‘underground carbon dioxide sequestration via bulk

CO2 injection is not feasible at any cost,’’ since the CO2 would require up to 500 

times more space underground than the carbon did when it was bound as coal, 

oil or natural gas. (Could we please enter the journal article into the record?)

a. If this hypothesis is correct, how would this affect your estimation on the feasibility of geoengineering as a viable option from a technological and a cost 

effectiveness point of view?

b. How would such a hypothesis alter the debate that is currently ongoing about 

the need to mitigate climate change through reducing emissions?

A2a. There will be physical limits to storage of CO2 in geologic deposits, in the 

oceans, and in silicate rock. Depending on the policy being contemplated, these limits may not matter. The cost of direct carbon dioxide removal from the air is very 

high, and so I think this technology is most likely to be used only if the threat of 

abrupt and catastrophic climate change appeared very great (carbon capture and 

storage from the power plant is less costly). I do think this is a very important technology. It is the only true ‘‘backstop’’ technology we have for reducing emissions. It 

would be a very good technology to have were geoengineering in the form of ‘‘solar 

radiation management’’ to be tried and found to have serious and undesirable consequences.

A2b. This is an illustration of why we need more research. This finding, if supported by further analysis, would vastly strengthen the case for reducing emissions 

by means other than underground storage.

Q3. Is it possible that a steep decline in greenhouse gas (GHG) emissions may well 

cost more than the perceived value of its benefits?

A3. All economic analyses of climate change that I am aware of find that the benefits of reducing greenhouse gas emissions a little vastly exceed the cost. Some studies support steeper reductions. A few commend very substantial reductions immediately. The different conclusions depend on many things, but two factors are crucial. The first is the rate of discount, since the benefits of reducing emissions will 

be realized decades after the costs have been incurred. The second is the prospect 

of catastrophic consequences from not reducing emissions. My view is that the second factor is ultimately the most important, and that the prospect of very serious 

consequences will only grow over time and at an accelerated rate as we do less to 

limit emissions now. I know of no economic analysis that suggests we should not 

be developing a substantial, serious, global effort to reduce greenhouse gas emissions.

Q4. In your testimony, you list five things that we should do to mitigate anthropogenic climate change. You state that research into geoengineering should be the 

last option.

a. Does this mean that you think our research dollars would be betterspent on 

energy efficiency or renewable energy research?

b. Is there a way to really calculate a return on investment when itcomes to 

geoengineering?

Aa. We should not put all of our research dollars in one basket. We should spread 

this money around, so that the returns in every category are roughly equal at the 

margin. I think the greatest priority today should be to invest in research that can 

allow us to reduce emissions at lower cost. But we should also spend research dollars on adaptation technologies, direct carbon capture removal and storage, and 

solar radiation management.

b. As noted above, we need to balance our investments so that they offer a nearequal return at the margin. A convenient way to think of this is to ask which technologies would be deployed were carbon priced at the ‘‘social cost of carbon.’’ This 
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concept derives a cost per ton of carbon dioxide by taking into account the effect 

of emissions on concentrations, concentrations on radiative forcing, radiative forcing 

on temperature, and temperature on ‘‘damages.’’ In the case of ‘‘solar radiation management’’ we cannot make a direct comparison with emission reductions, because 

SRM would affect temperature via a different mechanism, because it would entail 

new risks, and because it would not address related environmental problems like 

ocean acidification. But, in principle, a return can be calculated.

Q5. In previous hearings, we have heard from witnesses that the technologies required to achieve sufficient mitigation action are available and affordable right 

now.

a. Do you think this is an accurate statement? If so, would you please comment 

on what those technologies are?

b. Would you consider carbon capture and sequestration technologies available 

and affordable?

c. Would you consider the installation and use of such technologies available 

and affordable?

Aa. The technologies required to reduce emissions substantially certainly exist. We 

could simply shut down all our coal-fired power plants, turn off our natural gas 

transmission lines, and close every gasoline station. This is feasible. But it’s not desirable; it would be too harmful to welfare, given our understanding of the benefit 

of reducing emissions. So we need to take less drastic measures. We need to conserve energy; we need to reduce emissions per unit of energy; we need to invest 

more in renewable energy technologies and nuclear power. And we need to invest 

in complementary technologies for storage and transmission and in R&D to develop 

new technologies that will allow us to reduce emissions more cheaply in the future.

b. Carbon capture and sequestration is already being done, so this technology is 

available. However, it is not being done at the scale of a power plant and in the 

range of environments needed to demonstrate its effectiveness, safety, and cost 

around the world. This is why more research and development must be spent on 

pilot projects. Whether this technology is affordable depends on whether we think 

climate change is a risk worth making sacrifices to avoid. A different way to think 

about R&D is whether we would like the option to use this technology at some point 

in the future, and want to find out now whether it works, and whether its operation 

is efficient and safe. In my view, this should be a top priority for R&D funding.

c. Again, we need to establish a number of such stations around the world, just to 

demonstrate its effectiveness, safety, and cost. This should be our first priority. We 

should be doing this now. There is no reason for delay. After we learn from these 

projects, we’ll know if we should encourage or even mandate use of this technology. 

Based on the engineering cost estimates developed so far, it is likely that economics 

will favor deployment of this technology (in conjunction with many other efforts) in 

the very near future. But, again, let’s build and operate the pilot plants first. Our 

efforts to address this great challenge will need to unfold over a very long period 

of time, but it is long past time to get started.
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ANSWERS TO POST-HEARING QUESTIONS

Responses by Jane Long, Deputy Principal Associate Director at Large and Fellow, 

Center for Global Strategic Research, Lawrence Livermore National Lab

Questions submitted by Chairman Bart Gordon

Q1. Geoengineering is an emerging field, and as such, it does not have a standard, 

widely agreed upon definition.

a. How is geoengineering being defined today?

b. Discuss the pros and cons of the existing definitions.

c. Lastly, how should geoengineering be defined going forward?

A1. Geoengineering has been defined in several reports as intentional intervention 

in the climate. However the term itself carries an implication that we know enough 

to design a modification and implement it, i.e. to ‘‘engineer’’ the geosphere. The term 

is also used as an umbrella for at least two if not three entirely different types of 

technology—carbon dioxide removal, solar radiation management and a catch all 

category for things we largely haven’t thought of yet. These categories are different 

in goal, cost, speed of action and risk. They have little in common except they are 

all responses to climate conditions we determine are dangerous. 

Unfortunately, the term geoengineering has stuck and is probably not easy to lose 

at this point. What we could do is use better terms for the various categories and 

make it clear which we are talking about. I suggest we talk about (at least) two 

categories and call them:

• Climate remediation: The act of removing greenhouse gases from the atmosphere and storing them somewhere else such as deep underground.

• Climate intervention: The intentional modification of the climate to counteract climate forcing caused anthropogenic emission of greenhouse gases.

Q2. Which Federal research agencies or programs, as well as which non-Federal institutions such as universities, have the capacity to contribute to potential 

geoengineering research programs?

a. Which agencies or programs should not be involved? Why?

A2. Any institution which is currently doing research in climate science can probably contribute to climate intervention research at some level. The U.S. Global 

Change program includes thirteen agencies that contribute to data collection and assimilation, modeling and evaluation (http://www.globalchange.gov/). The agencies 

cooperate in this program and have formed a number of interagency working groups 

all of which have some application to climate intervention:

• Atmospheric Composition

• Climate Variability and Change

• Communications

• Ecosystems

• Global Carbon Cycle

• Global Water Cycle

• Human Contributions and Responses

• International Research and Coo aeration

• Land Use and Land Cover Change

• Observationsand Monitoring

Some of the major challenges in with climate science are also key to understanding how climate intervention might work. For example, the role of aerosols and 

clouds are difficult to get right in climate models and are the subject of major research efforts in climate science. These issues correspond exactly the two most 

prominent ideas for climate intervention: SRM and cloud brightening. So the university and lab research programs that address aerosols and clouds are the right place 

to start in developing a climate intervention program. 

That said, there is a need for much different kinds of research than is currently 

being carried out. For example, any significant climate intervention research will be 

controversial and it is best that the entire research process—from the call for proposals to the actual implementation of the research—involve governance, public engagement and international collaboration. The existing research in climate science 

is not conducted with a need for governance and public engagement although it does 
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involve extensive international collaboration. Most likely, a research program in climate intervention will have to build a new administrative structure to handle this 

problem and it is not obvious where best to place this activity. 

Likewise, any institution doing work in CCS can probably contribute to climate 

remediation research. For example, DOE’s Fossil Energy program conducts work in 

the capture of CO2 from flue gas. It would make sense to expand this program to 

include air capture work. 

We will need international collaboration should we ever decide we need to deploy 

geoengineering. There fore, it would be wise to frame a geoengineering research program as an international effort with collaboration and transparency at its heart. If 

a U.S. geoengineering research is viewed as a national defense program, it will send 

a message to the international community that is most likely to interfere with future collaboration. As such, basing this program in the Department of Defense 

would be unwise.

Q3. Explain the term ‘‘adaptive management’’ and discuss how it could be used with 

climate change and geoengineering research.

a. What are the advantages and disadvantages of an adaptive management approach to research?

b. Why is adaptive management not being more fully utilized today in federal 

research projects in these and other research areas?

A3. Adaptive management is a way to run a project when the system you are managing is very complex and you are not sure you can control the outcomes of your 

management choices. (The alternative to adaptive management would he to make 

a choice and stick to it no matter what happens.) When we conduct a climate intervention experiment, we will be perturbing a very complex, dynamic climate system 

and we will not be able to predict the outcome of our interventions with complete 

certainty. So, it will be wise to observe the results of the intervention and, if things 

are not going the way we hoped they would, respond with a new decision about 

what to do. This is a fairly simple and obvious idea, but it is difficult to do in practice. 

Imagine how difficult it will be to make a decision to an intervention in the climate by, for example, injecting aerosols into the stratosphere. But for the sake of 

argument, imagine that we somehow do make that decision and some years later 

we see little effect on temperature or perhaps it becomes extremely cold or we see 

abnormal and destructive weather patterns. It is fairly obvious that we should not 

ignore this data. We should re-evaluate the decision. Maybe we should decrease the 

injections, maybe we should increase them. Maybe we should counter the bad effects 

with some other action. These will be very difficult decisions for two major reasons. 

First, we will not be sure that the negative effects are actually caused by our interventions. They could just be normal climate variability and it will be hard to tell 

the difference. Second, if we had political trouble making a decision to act, imagine 

how difficult it will be to change direction. 

The ability to relate cause (climate intervention) and effect (a change in the climate) should be a major part of a geoengineering research program. If we are not 

able to determine whether the actions we have taken are causing a change in the 

climate, then we are flying blind with a lot at risk. Secondly, we need to social 

science research on the institutional structure for making adaptive 

decisions. For example, adaptively managed projects work best when there is an 

a priori agreement to re-evaluate management choices on a regular prescribed 

schedule in prescribed process. Research should focus on how best to structure this 

process.

Questions submitted by Representative Ralph M. Hall

Q1. There are several basic questions about the governance of geoengineering that 

need to be explored before delving into this research. On the international side:

a. If we were to enter into an international agreement to explore cooperative research efforts into geoengineering, which countries would necessarily need to 

be included?

b. Do you envision such an agreement facing resistance similar to previous attempts at global agreements addressing climate change?

c. How would a global partnership be structured?

d. Would certain countries be required to provide more resources than others? 

If a country provided more resources, would they have more decision-making 

authority or more input?
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e. Should we be looking at this issue as a national security problem; not unlike 

a rogue state or terrorist group that releases a biological chemical or nuclear 

weapon on some unsuspecting populace?

f. Could the actions of a lone ‘‘climate savior’’ have global effects, that would rise 

to this level of concern? Or is the technology really not in a place where this 

is an issue now? Should we be discussing it for the future?

On the domestic side:

g. There are several existing federal laws that could cover some, but not all, aspects of geoengineering. What are the specific gaps in the domestic federal 

framework that would be needed for us to move forward with this? How much 

would such a regulatory structure cost to implement?

h. Would the decision to deploy such a technology be appropriate for government 

only? Or, if there is private sector investment and work in this area, should 

they have a say in the decision? Are there any safeguards for the private sector to prevent the government from deploying such a technology?

i. Would the domestic decision to deploy a geoengineering technology be similar 

to the Presidential decision-making power to use nuclear weapons? Or, would 

this type of deployment benefit from the input of the Congressional and judicial branches of government?

j. If we were to deploy such a technology, and it did not work as expected, where 

would the liability for the unintended consequences lie? With those who developed the technology, or with those who decided to use it?

Aa. It may be possible to group countries into different categories and involve each 

category in a different way. At one end of the spectrum, there will be a small number of countries that will have geoengineering research programs (U.K. may be an 

example). With these countries we should have strong collaboration. Other countries 

may have scientists involved in our projects. Any country should be able to observe 

the research and know what we are doing.

b. The dynamics of international agreements for climate intervention may be quite 

different than for mitigation. It is quite difficult for single countries to commit to 

mitigation measures on their own. The dynamics of international negotiations on 

mitigation focus on trying to get everyone to mitigate at the same time. In contrast, 

international agreements on climate intervention should act to prevent a single 

country or non-state actor from making a climate intervention on their own and 

build relationships and institutions that will help us make appropriate global decisions in the future.

c. Global partnerships in research could be structured to share observational obligations, conduct model intercomparisons and conduct collaborative experiments. As 

well, other agreements might include agreements for consultation, the right to observe and receive research results, and participation in governance exercises.

d. For the case of climate intervention, the costs are quite likely minimal. Thus the 

use of economic contribution as way to determine who gets to say what is done 

seems irrelevant. In the case of climate remediation, the negotiation is quite similar 

to mitigation. The costs are relatively high and everyone benefits from deployment. 

Thus the framework for, and dynamics of international agreements on climate remediation might be quite similar to the framework and dynamics of mitigation.

e. I do not think that terrorism or rogue state actors are a good analogy for this 

problem. This is a new international problem and deserves its own careful analysis. 

What would happen if a single country or group of countries decides that they 

should act? What would happen if we think we should act? I do not think there is 

a perfect analogue for this situation in history. The likely motivations are quite different than terrorism and the ability to act is different.

f. I see little danger of an actor perpetrating an effective climate intervention in the 

immediate future. There are still technical issues to solve and the risks of using 

intervention today are much greater than the problems we are currently experiencing in the current climate. In the future, if the climate deteriorates and countries 

become desperate, it could become an issue.

g. We do not have in place a system to govern geoengineering research. This should 

involve the development of governing principles, public engagement and a process 

and structure for adaptive management of large field experiments. The costs associated with developing these are probably not large. The difficulty is that we have 

no historical model that fits this issue, Consequently we need to work hard to develop a thoughtful approach to governance, public engagement and the principles we 
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wish to act under. I think a good approach would be to develop some experiments 

in research governance and public engagement to evaluate the best course of action.

h. Public sector involvement makes a lot of sense for climate remediation technologies. We can use the power of innovation in the market to develop faster, better, 

cheaper ways to remove CO2 from the atmosphere, but only if there is a price for 

carbon which drives the market to develop this industry. As long as there is no price 

for carbon, geologic storage of CO2 could be thought of as a public service, like picking up the garbage. In the case of climate intervention, public sector engagement 

raises the spector of vested financial interests lobbying for programs that benefit 

their companies, rather than the future of the Earth. It is my opinion that we 

should think of all climate intervention technologies—not to mention deployment—

as a public good. One idea is to manage climate intervention like a regulated utility. 

Another might be a non-profit public/private partnership. Public policy research 

should be part of a geoengineering research program to help illuminate good choices 

for managing public/private relationships in climate intervention.

i. This question is clearly beyond my expertise, but I don’t think there is any perfect 

analogue for this situation. The questions of who decides, how they decide and when 

to deploy climate intervention technology is terra incognito.

j. My expertise is technical, not legal, but I would agree liability is an issue.

Q2. Several months ago, a paper was published in the journal of Petroleum Science 

and Engineering titled, ‘‘Sequestering carbon dioxide in a close underground volume.’’ The authors of this study, Christine Ehlig Economides and Michael J. 

Economides suggest that ‘‘underground, carbon dioxide sequestration via bulk 

CO2-injection is not feasible at any cost,’’ since the CO2 would require up to 500 

times more space underground than the carbon ,did when it was bound as coal, 

oil or natural gas. (Could we please enter the journal article into the record?)

a. If this hypothesis is correct, how would this affect your estimation on the feasibility of geoengineering as a viable option from a technological and a cost 

effectiveness point of view?

b. How would such a hypothesis alter the debate that is currently ongoing about 

the need to mitigate climate change through reducing emissions?

Aa. Evidence to date does not support the hypothesis put forward by Economides 

and Economides. The actual CO2 injection cases currently under way do not behave 

as these authors predict. It is quite likely that their assumptions are not correct. 

They apparently assume that the reservoirs act like closed systems and the more 

CO2 that is injected, the higher the pressure in the reservoir, making it harder and 

harder to continue to inject CO2. In practice, the pressure build-ups predicted by 

Economides and Economides are not observed. The fact that there are four large 

commercial end-to-end, integrated carbon dioxide capture and facilities currently in 

operation around disproves the Economides and Economides assertion that carbon 

dioxide capture and storage cannot work at any price. They have not been observed 

in pilot projects (e.g., Frio Brine pilot, South Liberty Texas) or in commercial 

projects (Mississippi’s Cranfield project, In Salah in Algeria, or Sleipner in the 

North Sea). Some reservoirs, for example in the Illinois basin, are thought to be so 

permeable that pressures may not increase very much at all due to injection. 

Economides and Economides seem to have an opinion about how CO2 injection will 

work that is at odds both with actual data and with a significant number of scientists and engineers involved carbon sequestration. I am aware that scientists in 

the U.S. and in Europe are working on critiques of the Ehlig-Economides and 

Economides paper to be submitted to the same journal in which Ehlig-Economides 

and Economides published. Three useful as yet unpublished analyses of the faults 

in their paper can be found in JJ Dooley and CL Davidson, 2010. ‘‘A Brief Technical 

Critique of Ehlig-Economides and Economides 2010 ’Sequestering Carbon Dioxide in 

a Closed Underground Volume.’’ ‘‘PNNL–19249. Joint Global Change Research Institute, Pacific Northwest National Laboratory, College Park, MD. April 2010, Comments on Economides and Ehlig-Economides, ‘‘Sequestering carbon dioxide in a 

closed underground volume,’’ SPE 124430, Oct. 2009’’ by the Geologic Carbon Sequestration Program, Lawrence Berkeley National Laboratory, by Oldenburg, 

Pruess, Birkholzer, and Doughty, Oct. 22, 2009 and finally American Petroleum Institute (API) comments on: Sequestering Carbon Dioxide in a Closed Underground 

Volume.

b. Whether they are right or wrong, it doesn’t change the dire need to mitigate climate change by reducing emissions. It will be very difficult to reduce emissions unless CCS is deployed because it will be difficult to stop generating electricity with 
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coal for some time. CCS is not a solution that will work for ever. It is a way to reduce emissions from coal while alternative energy systems are developed.

Q3. It has been suggested in prior hearings that one of the shortcomings of solar radiation management geoengineering is that it could produce drought in Asia 

and Africa and threaten the food supply for billions of people. Some scientists 

have suggested that global climate change could have the same result; others 

have suggested that it will actually increase agricultural production in some 

areas of the world.

a. If we were to undertake some type of large-scale geoengineering experiment, 

how would we be able to differentiate between the effects of global climate 

change and those from geoengineering and make the necessary modifications 

to prevent catastrophe?

b. If we were able to differentiate between the effects of global climate change 

and effects from geoengineering, is it now possible to determine whether a 

drought is caused by anthropogenic climate change or just natural variability?

A3. These issues were addressed in my written testimony and are abstracted here. 

A significant issue for geoengineering is to be able to differentiate between the effects of natural climate variability, human induced climate change, and 

geoengineering induced climate intervention. The science of detection and attribution of human effects on climate has advanced tremendously in the past decades. 

But the challenge of detecting and attributing changes to intentional, fairly short 

term interventions has not been met. This must be a focus of research. We cannot 

now, or perhaps ever, be able to perfectly differentiate various causes from various 

effects. We can, however, improve our ability to do so. 

In the simplest terms, the scientific approach to attribution of human induced climate change—whether through unintentional emissions or intentional climate intervention—is to use climate models to simulate climate behavior in two ways: one 

with and one without the human activity in question. If the results of the simulations including the human activity clearly match observations better than the results without the activity, then scientists say they have ‘‘fingerprinted’’ the activity 

as causing a change in the climate. Perhaps the most famous illustration in the 

International Panel on Climate Change (IPCC) reports shows two sets of multiple 

model simulations of mean global temperature over the twentieth century, one with 

and the other without emitted greenhouse gases. On top of this plot, the actual temperature record lines up squarely in the middle of the model results that included 

greenhouse gas emissions. This plot is a ‘‘fingerprint’ for human induced warming. 

Scientists have gone far beyond mean global temperature as a metric for climate 

change. Temperature profiles in the atmosphere and ocean, the patterns of temperature around the globe and even recently the time of peak stream flow have been 

used to fingerprint human induced warming. 

The science of fingerprinting is becoming more and more sophisticated. Increasingly, scientists are looking at patterns of observations rather than a single number 

like mean temperature. Patternmatching is a much more robust indicator of causality because it is much harder to explain alternative causality for a geographic or 

time-series pattern than for a time series of a single parameter. A famous example 

of this was discerning between global warming caused by emissions versus caused 

by a change in solar radiation. Solar radiation changes could not account for the 

observed pattern of cooling of the stratosphere occurring simultaneously with a 

warming of the troposphere, but this is exactly what models predicted for emission 

forced climate change. There do exist ‘‘killer metrics’’ like this that tightly constrain 

the possible causes of climate observations. 

Scientists are constantly trying to improve our ability to predict future climate 

states. Recently, Santer et al. showed that it possible to rank individual models with 

respect to their particular skill at predicting different aspects of future climate. http: 

//www.pnas.org/content/106/35/14778.full?sid=e20c4c31-5ab1-4f69-b541-

5158e62e4baf). Some think that the ability to detect and attribute intentional climate intervention will be nearly impossible. The fingerprinting of human induced 

climate change has been based on decades of data under extremely large human induced perturbations. For climate intervention, we contemplate much smaller perturbations. and would like proof positive of their consequences in a matter of years. 

Even though this is clearly a big challenge, it is not hopeless. Neither should we 

expect a panacea. We will be able to identify specific observations that certain models are better at predicting and we will be able to find some ‘‘killer metrics’’ that 

constrain the possible causes of the observations. In some respects, conclusive results will not be possible and if we ever come to deploy, we will likely have to deal 
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with this. Fingerprinting—detection and attribution of human intervention effects 

on climate—must be an important area for research if we are to be able to conduct 

adaptive and successful management of geoengineering.
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ANSWERS TO POST-HEARING QUESTIONS

Responses by Granger Morgan, Professor and Department Head, Department of Engineering and Public Policy, and Lord Chair Professor in Engineering, Carnegie 

Mellon University

Questions submitted by Chairman Bart Gordon

Q1. Geoengineering is an emerging field, and as such, it does not have a standard, 

widely agreed upon definition.

a. How is geoengineering being defined today?

b. Discuss the pros and cons of the existing definitions.

c. Lastly, how should geoengineering be defined going forward?

A1. Unfortunately, there is today no standard definition of geoengineering. The result in recent years has been that a wide range of very different activities have gotten lumped together under this heading. This is not helpful in promoting reasoned 

discourse because it allows people to make general assertions that in fact apply to 

only a subset of what others think they are talking about. 

In its report of September 2009, the Royal Society defined geoengineering as ‘‘the 

deliberate large-scale intervention in the Earth’s climate system . . ..’’ That report 

then goes on to introduce two additional terms:

• Carbon dioxide removal, or CDR, defined as techniques that remove greenhouse gases from the atmosphere.

• Solar radiation management, or SRM, defined as techniques that offset the 

effects of increased greenhouse gas concentrations by causing the earth to absorb less solar radiation.

In most of our recent work, my colleagues and I have stopped using the phrase 

geoengineering and instead are now using SRM. 

All methods of CDR are inherently slow and many are local in scale. The most 

promising methods of SRM are potentially very fast and are global in scale. In my 

view, these methods of SRM that present significant new challenges of national and 

international regulations and governance.

Q2. Which Federal research agencies or programs, as well as which non-Federal institutions such as universities, have the capacity to contribute to potential 

geoengineering research programs?

a. Which agencies or programs should not be involved? Why?

A2. I argued in my testimony that it would be best if the first phase of research 

on SRM were supported by the National Science Foundation. I made this argument 

for two reasons:

1. NSF does a good job of supporting open investigator initiated research and 

we need a lot of bright people thinking about this topic from different perspectives in an open and transparent way before we get very far down the 

road of developing any serious programs of field research.

2. In addition to natural science and engineering, NSF supports research in the 

social and behavioral sciences. Perspectives and research strategies from 

those fields needs to be brought to bear on SRM as soon as possible.

During the Q&A I was asked why DoE should not be the lead agency on early 

stages of SRM research. In contrast to work supported by NSF, research programs 

conducted through DoE often do not engage as wide a range of investigators and 

institutions. They frequently start with a more focused prior definition of what problems should be addressed and how that should be done. They often do a poorer job 

of incorporating relevant behavioral social science and do not always draw in the 

best academic research. 

Clearly, the modeling and other capabilities of the DoE national labs, as well as 

other laboratories, such as NCAR, NASA, Goddard, and GFDL, should be used in 

support of research on SRM. That, however, is different from placing lead responsibility with those agencies. 

In my testimony, I also argued that once it becomes clear that we need to be doing 

some larger scale field studies, then it would be appropriate to engage NASA and 

or NOAA. I also see no problem with involving the military in providing logistical 

support to such research, when they have the most appropriate assets. 
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A key point is that any research undertaken on SRM should be open and transparent. It is for that reason that I believe that it would be entirely inappropriate 

for the intelligence community to be involved in the experimental aspects of SRM 

research. We should also work hard to avoid getting ourselves into a situation in 

which private parties develop an interest in promoting the deployment of SRM because they stand to gain financially from such deployment.

Q3. In your testimony, you discuss the need for an international scientific body to 

provide oversight for geoengineering research at this time, rather than a formal 

international agreement to govern research.

a. What types and at what scale would research be conducted under the purview 

of such a scientific body?

b. At what point would it be prudent for a binding international agreement on 

geoengineering research to be instituted, if ever?

A3. I believe that it would be premature to seek any sort of formal international 

accord on SRM today, since there does not appear to be any state or other party 

about to engage in this activity. Before moving to any formal international negotiation on this topic it would be highly desirable to have completed serious research 

so that negotiations can be based on a better understanding that we have today. 

My colleagues and I discuss these issues at greater length in the paper from Foreign 

Affairs that I submitted with my testimony. 

I argued in my testimony that ‘‘so long as it is public, transparent, and modest 

in scale, and informally coordinated within the scientific community (e.g., by a group 

of leading national academies, the international council of scientific unions (ICSU), 

or some similar group) I believe there should be no constraints on modest low-level 

field testing, done in an open and transparent manner, designed to better understand what is and is not possible, what it might cost, and what possible unintended 

consequences might result.’’

I went on to argue that giving meaning to the phrase ‘‘modest low-level field testing’’ should be top priority for the early phase of a U.S. research program on SRM. 

The point of the diagrams I showed was to give more concrete meaning to that argument. 

The Royal Society is at present taking the lead in facilitating the next round of 

international discussion among experts and others on how issues of global governance might best proceed. A description of that process is provided below:

It is my view that this is an appropriate way to proceed. Any move to negotiate 

some sort of treaty arrangement now, before we have a better technical understanding of SRM, would in my view be premature.

Questions submitted by Representative Ralph M. Hall

Q1. Dr. Morgan, right now, the Department of Energy is heavily engaged in modeling the climate system, biological and atmospheric interactions and the carbon 

cycle. Yet, in your testimony, you suggest that when it comes to geoengineering, 

the Department of Energy should not be involved in these activities. Instead, you 
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recommend that the National Science Foundation, NOAA or NASA be tasked 

with developing instrumentation and research plans to study solar radiation 

management events. Why do you think that DOE should not be involved? Do you 

think they have reached beyond their original mission?

A1. As I argued in my response to Chairman Gordon’s second question above, clearly the modeling and other capabilities of the DoE national labs, as well as those 

of other laboratories, such as NCAR, NASA, Goddard, and GFDL, should be used 

in support of research on SRM. That, however, is different from placing lead responsibility for the initial phase of research on SRM with DoE or some other agency. 

In contrast to work supported by NSF, research programs conducted through DoE 

often do not engage as wide a range of investigators and institutions. They frequently start with a more focused prior definition of what problems should be addressed and how. They often do a poorer job of incorporating relevant behavioral 

social science and do not always draw in the best academic research. 

Our nation faces enormous challenges in transforming the energy system: both in 

lowering the environmental footprint and the cost of producing and moving energy 

to end users, and in improving efficiency with which we convert that energy into 

useful services. Given the enormity of the challenges we face, I believe that DOE 

should focus as much of its attention and resources as possible on advancing these 

objectives and avoid getting diverted into yet more areas.

Q2. You mention the need for a more formal international oversight mechanism that 

will grow as the research continues. Would you suggest a group such as the 

Intergovernmental Panel on Climate Change being in charge of such a mission? 

Why or why not?

A2. I am not an expert in international relations so this question might better be 

directed to some of the political scientists with whom I have worked on issues related to SRM. Three who have been thinking about SRM and have somewhat dissimilar views are John Steinbrenner at the University of Maryland, David Victor 

at UCSD or Ted Parson at Michigan. 

That said, I view the multi-party follow-on study on governance issues related to 

SRM that has been initiated by the Royal Society to be an excellent next step. In 

my response to Chairman Gordon’s 3rd question, I provided a description of that 

process.

Q3. In previous hearings on this issue, some witnesses suggested that regardless of 

how much research we perform ahead of time, we will never really know the true 

effects geoenginering would have on the planet without actually doing it because 

of all the possible variables. Is that an accurate statement? How accurate is that 

for other technological ventures we have undertaken?

A3. Certainly we can never expect to learn all the effects that large-scale implementation of SRM might have before its possible implementation. But, a well-designed 

research program can be expected to provide considerably more understanding and 

insight than we now possess. The situation we face can be illustrated with a series 

of simple decision trees as shown on the following page.
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355

Q4. Several months ago, a paper was published in the Journal of Petroleum Science 

and Engineering titled, ‘‘Sequestering carbon dioxide in a close underground volume.’’ The authors of this study, Christine Ehlig-Economides and Michael J. 

Economides suggest that ‘‘underground carbon dioxide sequestration via bulk 

CO2 injection is not feasible at any cost,’’ since the CO2 would require up to 500 

times more space underground than the carbon did when it was bound as coal, 

oil or natural gas.

a. If this hypothesis is correct, how would this affect your estimation on the feasibility of geoengineering as a viable option from a technological and a cost 

effectiveness point of view?

b. How would such a hypothesis alter the debate that is currently ongoing about 

the need to mitigate climate change through reducing emissions?

A4. In April, J.J. Dooley and C.L. Davidson at PPNL prepared an assessment of 

this paper for the Department of Energy (PNNL–19249). The summary of their report reads in part as follows:

‘‘. . . the paper is built upon two flawed premises: first, that effective CO2 storage requires the presence of complete structural closure bounded on all sides 

by impermeable media, and second, that any other storage system is guaranteed to leak. These two assumptions inform every aspect of the authors’ analyses, and without them, the paper fails to prove its conclusions. The assertion 

put forward by Ehlig-Economides and Economides that anthropogenic CO2 cannot be stored in deep geologic formations is refuted by even the most cursory 

examination of the more than 25 years of accumulated commercial carbon dioxide capture and storage experience.’’

The American Petroleum. Institute has also prepared a critique. The following is 

an excerpt from the summary of their assessment:

‘‘. . . the fundamental premise of the paper—that sequestration at the individual project-level will occur in ‘‘closed underground volumes’’—can be characterized as very conservative, bordering on unrealistic. By making this assumption, the authors are effectively characterizing all geologic formations used for 

CO2 storage as sealed, pressure tight containers with storage capacities limited 

by pressure constraints. While this condition can occur, it is unrealistic to assume it as the ‘‘baseline’’ condition in all potential storage reservoirs.

The oil and gas industry’s vast experience clearly shows that truly closed reservoirs are relatively uncommon. Industry experience shows that a majority of 

producing geologic formations have some form of pressure communication across 

very broad areas. There is little reason to expect significantly different conditions (i.e. the supposed pressure containment) in saline portions of those same 

geologic formations or saline reservoirs that under- or over-lay those same formations . . ..’’

Geological sequestration of carbon dioxide falls under the category of CDR. While 

it does not appear that the assessment by Ehlig-Economides is correct, its validity 

has little bearing on the ‘‘feasibility’’ of SRM, the type of geoengineering I discussed. 

Nor does the volume of available pore space for use in CCS have any relevance to 

the question of whether we should be reducing CO2 emissions. 

We need to reduce global CO2 emissions by roughly an order of magnitude over 

the course of the next few decades if we are to avoid very major, and probably irreversible, climate change. How much pore space may be available to sequester CO2

has no bearing on that fact. 

There is no single technological silver bullet that will achieve a major reduction 

of CO2 emissions. Doing that will require a cost-effective portfolio of all available 

strategies and technologies. The volume of pore space available for sequestration 

might change the composition of that portfolio but will have no impact on the need 

to achieve a major reduction in emissions. 

(357)

Appendix 2: 

ADDITIONAL MATERIAL FOR THE RECORD
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Æ