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S. HRG. 106–1128

CLIMATE CHANGE IMPACTS TO THE

UNITED STATES

HEARING

BEFORE THE

COMMITTEE ON COMMERCE, 

SCIENCE, AND TRANSPORTATION 

UNITED STATES SENATE

ONE HUNDRED SIXTH CONGRESS

SECOND SESSION

JULY 18, 2000

Printed for the use of the Committee on Commerce, Science, and Transportation

(

(II)

SENATE COMMITTEE ON COMMERCE, SCIENCE, AND TRANSPORTATION

ONE HUNDRED SIXTH CONGRESS

SECOND SESSION

JOHN MCCAIN, Arizona, Chairman 

TED STEVENS, Alaska 

CONRAD BURNS, Montana 

SLADE GORTON, Washington 

TRENT LOTT, Mississippi 

KAY BAILEY HUTCHISON, Texas 

OLYMPIA J. SNOWE, Maine 

JOHN ASHCROFT, Missouri 

BILL FRIST, Tennessee 

SPENCER ABRAHAM, Michigan 

SAM BROWNBACK, Kansas 

ERNEST F. HOLLINGS, South Carolina 

DANIEL K. INOUYE, Hawaii 

JOHN D. ROCKEFELLER IV, West Virginia 

JOHN F. KERRY, Massachusetts 

JOHN B. BREAUX, Louisiana 

RICHARD H. BRYAN, Nevada 

BYRON L. DORGAN, North Dakota 

RON WYDEN, Oregon 

MAX CLELAND, Georgia 

MARK BUSE, Republican Staff Director 

ANN CHOINIERE, Republican General Counsel 

KEVIN D. KAYES, Democratic Staff Director 

MOSES BOYD, Democratic Chief Counsel 

(III)

C O N T E N T S 

Page 

Hearing held on July 18, 2000 ............................................................................... 1

Statement of Senator McCain ................................................................................. 1

Prepared statement .......................................................................................... 2

Prepared statement of Senator Snowe ................................................................... 2

WITNESSES

Janetos, Dr. Anthony C., Senior Vice President for Program, World Resources 

Institute ................................................................................................................ 15

Joint prepared statement ................................................................................. 6

Karl, Thomas R., Director, National Climatic Data Center, National Environmental Satellite, Data, and Information Service, National Oceanic and Atmospheric Administration ................................................................................... 3

Joint prepared statement ................................................................................. 6

Melillo, Dr. Jerry M., Senior Scientist, Ecosystems Center, Marine Biological 

Laboratory, joint prepared statement ................................................................ 6

Schmitt, Dr. Raymond W., Senior Scientist, Woods Hole Oceanographic Institutions ................................................................................................................... 17

Prepared statement .......................................................................................... 19

Singer, Dr. S. Fred, Professor Emeritus of Environmental Sciences, University 

of Virginia, and Former Director of U.S. Weather Satellite Service ............... 25

Prepared statement .......................................................................................... 27

APPENDIX

The Annapolis Center, prepared statement .......................................................... 43

Climate Policy—from Rio to Kyoto: a Political Issue for 2000—and Beyond, 

Hoover Institution Essay by S. Fred Singer ...................................................... 55

Craig, Hon. Larry E., U.S. Senator from Idaho, prepared statement ................. 37

Robert Mendelsohn, Edwin Weyerhaeuser Davis Professor, Yale University, 

School of Forestry and Environmental Studies, letter dated July 12, 2000 

to Hon. John McCain ........................................................................................... 56

Murkowski, Hon. Frank H., U.S. Senator from Alaska, prepared statement .... 39

Response to written questions submitted by Hon. John McCain to: 

Thomas R. Karl ................................................................................................. 33

Dr. Anthony C. Janetos .................................................................................... 34

Dr. Raymond W. Schmitt ................................................................................. 35

Dr. S. Fred Singer ............................................................................................ 36

Rhines, Dr. Peter B., Professor, University of Washington, prepared statement ...................................................................................................................... 48

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CLIMATE CHANGE IMPACTS TO THE

UNITED STATES 

TUESDAY, JULY 18, 2000

U.S. SENATE, 

COMMITTEE ON COMMERCE, SCIENCE, AND TRANSPORTATION, 

Washington, DC. 

The Committee met, pursuant to notice, at 9:32 a.m. in room SR–

253, Russell Senate Office Building, Hon. John McCain, Chairman 

of the Committee, presiding. 

OPENING STATEMENT OF HON. JOHN MCCAIN,

U.S. SENATOR FROM ARIZONA 

The CHAIRMAN. Good morning. Earlier this year, we examined 

the science behind global warming as a means of defining the problem. Today we hope to further our efforts to understanding this 

issue by discussing the climate change impact on the United 

States, and the National Assessment Report. Because of the fact 

that at 9:45 a.m. we will begin a series of 11 votes, which will consume the entire morning, we have a problem. We contemplated delaying the rest of the hearing until this afternoon, but unfortunately, a number of our witnesses were not able to remain. 

So what I would like to do is begin with opening statements, go 

as long as we can, and then I will have to adjourn the hearing and 

reschedule it at a later date. With a vote every 10 minutes, I cannot keep the witnesses here for an extended period of time. It 

would not be fair to the witnesses, nor would it provide for a productive hearing. 

So what I would like to do is begin with our first panel, which 

is Dr. Thomas Karl, Director of the National Climatic Data Center, 

National Environmental Satellite, Data, and Information Service of 

NOAA, Dr. Anthony C. Janetos, Senior Vice President for Program, 

World Resources Institute, Dr. Raymond Schmitt, Senior Scientist, 

Woods Hole Oceanographic Institutions, and Dr. Fred Singer, Professor Emeritus of Environmental Sciences, University of Virginia. 

I would like to express my deep apology to all of the witnesses, 

particularly some who have come here from long distances. At this 

time of year, we affirm Mr. Bismarck’s statement that the two 

things you never want to see made are laws and sausages. These 

are very important hearings and very important witnesses, and we 

will reschedule at the earliest date. 

Mr. Karl, we will begin with you. 

[The prepared statement of Senator McCain follows:]

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PREPARED STATEMENT OF JOHN MCCAIN, U.S. SENATOR FROM ARIZONA

Earlier this year, we examined the science behind global warming as a means of 

defining the problem. Today, we hope to further our efforts to understand this issue 

by discussing the Climate Change Impact On the United States, the National Assessment Report. 

This morning we will examine, as noted in the National Assessment Report, climate change impacts on the United States. Because the report is currently in its 

60-day public comment period which ends August 11, we feel that this is an opportune time for the Committee to discuss this very important matter. We hope that 

today’s discussion will spur others to review the document and provide comments 

to the White House. 

I know that some have asked that today’s proceeding be postponed until later in 

the year. I feel this would be a mistake given the timeframe that the Administration 

has laid out for completing this report. I believe it is important to have this open 

discussion while the report is still in its draft form thus providing valuable input 

as it is finalized. Postponing this hearing will not afford the Committee the opportunity to examine the report before finalization. 

I look forward to hearing from our witnesses today. Although there are many 

issues that need to be addressed, I hope the witness will focus on the following: 

‘‘how can two computer models which give different results be used to reach a consensus conclusion,’’ why federally-funded U.S. models were not selected for the 

study, and what role does the ocean’s dynamics play in these analyses. 

As we review this document and other weather predictions, we should keep in 

mind that these predictions or forecasts have very real meanings to people and the 

economy. This past Sunday’s edition of The Washington Post contained an article 

that demonstrates the importance of accurate weather forecasting. 

The article states that the Department of Agriculture and National Weather Service officials predicted that severe drought could cripple the farm economy in much 

of the Midwest and Deep South. Secretary Glickman warned that the lack of rain 

could be ‘‘catastrophic’’ to farmers, and Jack Kelley, Director of the National Weather Service, observed that the Midwest drought was the worst since 1955. 

Farmers in the agricultural heartland took heed of the warning. Many who were 

storing their 1999 yields held off putting their crops on the market, reckoning that 

a drought-induced falloff in production this year would drive up prices. 

What happened was just the opposite. Timely rains and cooler-than-predicted 

temperatures have offered promise of bumper crops in much of the Midwest and 

other parts of the nation this fall, ensuring that grain and soybean prices will go 

down for the third straight year due to continuing oversupply. 

Last week, the Department of Agriculture lowered its price projections for corn, 

soybeans and wheat. The point being that a serious, sober examination of the topic 

is long overdue. 

Again, as noted, this is very serious business with real impacts to the American 

economy and the lives and well-being of our citizens. 

I welcome all of our witnesses here today.

[The prepared statement of Senator Snowe follows:]

PREPARED STATEMENT OF OLYMPIA J. SNOWE, U.S. SENATOR FROM MAINE

Thank you, Mr. Chairman, for calling this important hearing today to review the 

public review draft for the National Assessment Report: Climate Change Impacts 

on the United States, to which the public can respond until August 11. The report 

is the most comprehensive so far—giving us snapshots specifically for U.S. projections through computer modeling to help us determine potential human impacts on 

the climate change process. The Report assesses both geographic regions of the 

country and its socioeconomic sectors. Whether you agree with the different scenarios projected or not, it is a place for us to start. 

In 1990, this Committee reported out legislation that was ultimately signed into 

law by President George Bush, the U.S. Global Change Research Program Act, 

which, among other programs, called for a National Assessment Report to Congress. 

The Assessment may be an extremely important tool when we consider the long lifetimes of the buildup of greenhouse gases—particularly carbon dioxide—that have already been put into the atmosphere, both manmade and natural. 

Section 106 of the 1990 Public Law calls for a scientific assessment not less frequently than every four years. Quite frankly, I do not believe we should wait for 

another assessment in four years time, as I understand the United States has made 

great strides in modeling technologies and capabilities. I would like to think we are 

3

capable of pulling on our country’s best scientific modeling, as well as the Canadian 

and United Kingdom models used for the Assessment in a shorter time frame. We 

need the most updated research information so as to be able to make reasoned environmental and economic policy decisions. 

In looking at the potential impacts for my state, I noted projections that gave me 

great pause. Many in Maine would tell you that if the devastating Ice Storm the 

Assessment Report mentions that hit across the State in 1998 and paralyzed the 

state’s power infrastructure for over three weeks during bitter cold weather, is a 

harbinger of what we may expect with climate change, I believe they would want 

Congress to be paying more attention to the issue. 

Also noted in the Report are the possible changes in Northeast forests from conifer to deciduous trees, and the loss of an entire tourist industry if the range of our 

vibrant sugar maple trees shifts more northward into Canada; and the reduction of 

cold weather recreation that is vital to the State’s winter ski and snowmobile industry. 

On the brighter side, there may be the possibility for longer warm weather recreation, already a popular summer pastime in my State, a reduction for heating requirements in the winter—certainly good news considering the State’s energy problems last winter both with the supply and the price of home heating oil—and the 

prediction for increased crop and forest productivity. 

One of my biggest concerns is the possible consequences of pest and disease outbreaks if the climate continues to warm, implications for both human health and 

our economy. According to the report, the Northeast, because of warmer winter 

weather, may experience increased incidences of diseases such as Lyme disease or 

West Nile encephalitis—the same disease that was found for the first time in the 

New York City area last year, which killed 7 people. 

The Report says outbreaks are possible because of the increased survival of the 

reservoirs of infection, such as deer and white-face mice, and the vectors of infections, such as ticks and mosquitoes. If true, this is very disturbing. 

Also, there are also some common themes among the regions that are noteworthy. 

Over 50 percent of the U.S. population resides in the coastal zone. All coastal regions will have to adapt to changes in shoreline characteristics and marine resources as a result of climate change. The models do not clearly predict many of 

these changes and we need to improve our oceanic databases to strengthen these 

models. 

Even if the models are too high by 50 percent, we still need to know who and 

what may be affected—both the positive and the negative—so that informed environmental and economic decisions can be made for mitigation and adaptation. 

I look forward to the testimony and the discussion this morning, and once again, 

thank Senator McCain for again bringing focus to the issue of global climate change 

in this Committee as we have jurisdiction over many of the programs concerned 

with climate change. I thank the Chair.

STATEMENT OF THOMAS R. KARL, DIRECTOR, NATIONAL

CLIMATIC DATA CENTER, NATIONAL ENVIRONMENTAL

SATELLITE, DATA, AND INFORMATION SERVICE, NATIONAL

OCEANIC AND ATMOSPHERIC ADMINISTRATION 

Mr. KARL. Thank you, Senator. We very much appreciate the opportunity to comment on the National Assessment. I would like to 

begin with the statement that suggests that the relevant question 

in this assessment is not whether greenhouse gases are increasing 

due to human activities and contributing to global warming. Clearly they are. 

The CHAIRMAN. Would you pull the microphone a little bit closer? 

Mr. KARL. Rather, the question is, what will be the amount and 

rate of future warming and associated climate change impacts and 

how will those changes affect human and natural ecosystems? 

In this assessment we used climate model simulations with projected changes in greenhouse gases and aerosols comparable to 

those used in the business-as-usual cases conducted by the Intergovernmental Panel on Climate Change to assess those impacts on 

a regional basis across the nation. 

4

Our results indicate that climate change will vary widely across 

the nation, those impacts will vary widely, as will our vulnerability 

to climate change. What do we mean by vulnerability? Vulnerability is defined as the magnitude of the climate impact after consideration of adaptation measures to lessen those impacts. 

We appear to be particularly vulnerable to those impacts affecting natural ecosystems, but less vulnerable to those related to 

human-managed systems. We expect that the direct economic vulnerability is likely to be modest during the 21st Century for the 

kinds of climate scenarios we use in this assessment, but this, too, 

is likely to vary considerably from region to region. 

The two principal climate scenarios for the 21st Century in the 

assessment can be briefly summarized as: one scenario is warm 

and wet and the other is hot and dry. Some of the gross features 

include annual average temperature increases of about 5 to 10 degrees Fahrenheit. This is about five to ten times the increase that 

has occurred during the 20th Century. Changes in total precipitation are less certain. 

The CHAIRMAN. Have you ever seen changes like that before? 

Mr. KARL. No. 

The CHAIRMAN. Increases in temperature? 

Mr. KARL. No. This would be an unprecedented change this century. In fact, the temperature increases during the 20th Century 

we now believe to be larger than anything we have seen in the last 

thousand years. 

Changes in total precipitation are less certain, as indicated. For 

example, the wetter scenario has substantial increases in precipitation in the Southeast, about a 10- to 30-percent increase in precipitation. The drier scenario has about an equal decrease in precipitation. 

There are other aspects of precipitation that we do have more 

certainty about. For example, all the climate scenarios and the observations suggest that more precipitation will occur in heavy and 

extreme precipitation events, as opposed to the light and moderate 

events. 

All regions are affected by increases in the ability of the atmosphere to evaporate water from the surface as the temperature increases. This means that areas with marginal increases in precipitation are likely to be more vulnerable to more frequent extreme 

and severe drought. Other aspects of extreme weather, such as 

hurricane tracks, local severe weather, tornadoes, hail, et cetera, is 

still very uncertain. 

The CHAIRMAN. I do not understand why an increase in severe 

weather would be associated with climate change. 

Mr. KARL. Regarding the increase in heavy and extreme precipitation events, the best way to think about it is if you can imagine 

during the winter time in Alaska when you have precipitation, it 

falls in very light events. It is never very heavy. In converse, think 

about in the summertime, especially in the southern parts of the 

U.S., when it rains it rains very heavily, usually in short periods. 

This is the kind of trend that you will be seeing more frequently. 

We already see it in the observations. That is, precipitation tends 

to come in shorter bursts but heavier in magnitude. 

5

With respect to some of the notable regional impacts around the 

nation, based on scenarios we used, I will just mention a few. In 

Alaska, sharp increases in temperature during the cold season are 

very likely to cause continued thawing of the permafrost, further 

disrupting the forest ecosystem, roads and buildings in that area. 

There is already considerable evidence in the observations that 

that has taken place. 

In the Pacific Northwest there is likely to be more wintertime 

flooding and reduced spring flooding as snow pack decreases. Again 

the observations already show a significant decrease in snow, particularly in the West. This will put added stress on summer water 

supplies. Rising water temperatures will further complicate needed 

fish restoration efforts. 

In the Midwest, at least for the next few decades, it is likely we 

will see a continued increase in agricultural production, in large 

part due to the fertilization effect of carbon dioxide on crops. We 

expect reductions in lake levels are also likely, increasing the cost 

of transportation in the lakes and down the rivers, ship and barge 

transportation. Increased water temperatures are likely to lead to 

increased eutrophication and reduced oxygen levels in lakes and 

rivers. 

In the Northeast, climate change will very likely interact with 

many existing stresses in urban areas such as air quality, transportation, especially along the coast, due to rising sea level and storm 

surges, increased heat-related stresses, and effects on inflexible 

water supply systems. 

Other stresses are likely to be mitigated. For example, snow removal costs and extreme cold winter exposures. 

In the Southeast, generally the South does not reap the benefits 

of increased temperature for agricultural purposes, since temperatures are already quite warm. Along the Southeast gulf coast, inundation of coastal wetland is very likely to increase, threatening fertile areas for marine life, migrating birds, waterfowl. 

In the hotter and drier scenario grasslands and savannahs replace the southernmost forests in the Southeast, while the warmer 

weather scenario expands the range of the southern tree species, 

and large increases in the heat index (the combination of temperature and humidity) average 10 to over 25 degrees Fahrenheit increases that will make summer outdoor activities quite stressful. 

In the Great Plains, similar to the Midwest, higher CO2 concentrations are likely to offset the effects of rising temperatures, increasing agricultural yields and forest cover for several decades. 

Again, the southern portions of the Great Plains are not likely to 

reap these benefits. 

In the West, both scenarios project a substantial increase in precipitation, leading to a reduction in desert ecosystems, being replaced by shrublands. 

For our island States, more intense cycles of El Nin ̃ o and la nin ̃ a 

are possible, thereby increasing stresses on existing water supplies. 

These are just a few of the impacts we discuss in the National 

Assessment. I just wanted to mention that there are many issues 

we are uncertain about, especially issues that are interdependent. 

These could be important, even though we do not understand them. 

6

Further assessments will need to address many of these interdependencies. 

Thank you for the opportunity to make an opening statement. 

[The joint prepared statement of Mr. Karl, Dr. Melillo, and Dr. 

Janetos follow:]

JOINT PREPARED STATEMENT OF THOMAS R. KARL, DIRECTOR, NATIONAL CLIMATIC

DATA CENTER, NATIONAL ENVIRONMENTAL SATELLITE, DATA, AND INFORMATION

SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION; DR. JERRY M. 

MELILLO, SENIOR SCIENTIST, ECOSYSTEMS CENTER, MARINE BIOLOGICAL LABORATORY; AND ANTHONY C. JANETOS, SENIOR VICE PRESIDENT FOR PROGRAM, WORLD

RESOURCES INSTITUTE

We are very pleased to have the opportunity to address the Senate Committee on 

Commerce, Science, and Transportation on the topic of the potential impacts of climate variability and change on the U.S. Our draft assessment report, Climate 

Change Impacts on the United States: the Potential Consequences of Climate Variability and Change was released for a 60 day public comment period on Monday, 

June 12. It is an extensive synthesis of the best available scientific information on 

this important topic. 

There are three questions about climate change that dominate discussions of this 

important topic. How much climate change is going to occur? What will happen as 

a result? What can countries do about it? There are obviously heated political opinions about each of these, but the issues are real, and it is critical to understand the 

underlying scientific knowledge about each if sound decisions are to be made. The 

assessment report focuses on the second of these questions. 

A national assessment of the potential impacts of climate change was called for 

in the 1990 legislation that established the U.S. Global Change Research Program 

(USGCRP). For several years, the research program focused on developing the basic 

scientific knowledge that the international scientific assessment process overseen by 

the Intergovernmental Panel on Climate Change (IPCC) depends on. The IPCC was 

jointly established by the World Meteorological Organization and the United Nations Environmental Programme in 1988. As scientific research has provided compelling evidence that climate change is in fact occurring, it has become increasingly 

clear that there is a need to understand what is at stake for natural resources and 

human well-being in the U.S. In response to this need, in 1998, Dr. John H. Gibbons, then Science Advisor to the President, requested the USGCRP to undertake 

the national assessment originally called for in the legislation. Dr. Gibbons asked 

the USGCRP to investigate a series of important questions:

• What are the current environmental stresses and issues for the United States 

that form a backdrop for additional impacts of climate change?

• How might climate change and variability exacerbate or ameliorate existing 

problems?

• What are the priority research and information needs that can better prepare 

policy makers for making wise decisions related to climate change and variability? What information and answers to what key questions could help decision-makers make better-informed decisions about risk, priorities, and responses? What are the potential obstacles to information transfer?

• What research is most important to complete over the short term? Over the 

long term?

• What coping options exist that can build resilience to current environmental 

stresses, and also possibly lessen the impacts of climate change? How can we 

simultaneously build resilience and flexibility for the various sectors considering 

both the short and long-term implications?

• What natural resource planning and management options make most sense in 

the face of future uncertainty?

7

• What choices are available for improving our ability to adapt to climate change 

and variability and what are the consequences of those choices? How can we 

improve contingency planning? How can we improve criteria for land acquisition?

A variety of efforts emerged in response to Dr. Gibbons’ charge. 

Over twenty workshops were held around the country, involving academics, business-people representing a range of industries including manufacturing, power generation and tourism, and people who work closely with land and water ecosystems 

including resource managers, ranchers, farmers, foresters and fishermen. Each 

workshop identified a range of issues of concern to stakeholders in those regions, 

many of them quite unrelated to climate change, per se. Most workshops were followed by the initiation of scientific, university-led regional studies, some of which 

have finished their work, and others of which are ongoing. 

In addition to these kind of ‘‘bottom-up’’ efforts, it was decided that it was also 

necessary to create a national-level synthesis of what is known about the potential 

for climate impacts for the U.S. as a whole, addressing the issues identified in the 

regional workshops and national studies. This synthesis obviously needed to build 

on the work that had begun to emerge from the subsequent regional and national 

studies, but also to draw on the existing scientific literature and analyses done with 

the most up-to-date ecological and hydrological models and data that could be obtained. The National Assessment Synthesis Team (NAST) was established by the 

National Science Foundation as an independent committee under the Federal Advisory Committee Act (FACA) specifically in order to carry out this second step. This 

committee is made up of experts from academia, industry, government laboratories, 

and non-governmental organizations (NGO’s) (membership list is Attachment 1). In 

order to ensure openness and independence, all meetings of the NAST have been 

open to the public, all documents discussed in its meetings are available through 

the National Science Foundation, as are all the review comments already received 

and responses to them. This is perhaps out of the ordinary for a scientific study; 

but most scientific studies do not focus on issues of such broad and deep implications for American society, and about which there is such heated rhetoric. 

The NAST’s first action was to publish a plan for the conduct of the national synthesis. In addition, five issues (agriculture, water, forests, health, and coastal and 

marine systems), out of the many identified, were later selected by the National 

Synthesis Assessment Team (NAST) to be topics for national studies. Carrying out 

this plan has been a major undertaking. The end result has been the production 

of a comprehensive two-volume National Assessment Report, available to the public 

for a 60-day comment period. The ‘‘Foundation’’ volume is more than 600 pages long, 

with more than 200 figures and tables, with analyses of the five national sectors, 

and 9 regions that together cover the entire U.S. It is extensively referenced, and 

a commitment has been made that all sources used in its preparation are open and 

publicly available. The ‘‘Overview’’ volume is about 150 pages long, written in a 

style that is more accessible to the lay public, and summarizes the Foundation in 

a way that we hope will be understandable and informative, and which we are confident is scientifically sound. Both documents have already been through extensive 

review. At the end of 1999, two rounds of technical peer review were undertaken, 

and during the past spring, an additional review by about 20 experts outside the 

assessment process was undertaken. Over 300 sets of comments have been received 

from scientists in universities, industry, NGO’s, and government laboratories. The 

responses to all external comments have been described in comprehensive review 

memorandums. We are now in the final stage of the process, a 60 day public comment period specifically requested by Congress, after which final revisions will be 

done and the report submitted to the President and Congress, as called for in the 

original legislation. 

In order to ensure that the NAST has undertaken its charge well, an oversight 

panel was also established through the offices of the President’s Council of Advisors 

on Science and Technology (membership list is Attachment 2). The oversight panel 

is chaired by Dr. Peter Raven, Director of the Missouri Botanical Garden and recently retired Home Secretary of the National Academy of Sciences, and Dr. Mario 

Molina, Professor of Atmospheric Chemistry at MIT, and recent Nobel-prize winner 

for his research on stratospheric ozone depletion. Its membership, like the NAST’s, 

is drawn from academia, industry, and NGO’s. It has reviewed and approved of the 

plans for the assessment, reviewed each draft of the report, and reviewed the response of the NAST to all comments. 

What have been the results of this extraordinarily open process? What assumptions drive the analysis? What conclusions have been reached? 

8

It is important to realize that the national assessment does not attempt to predict 

exactly what the future will hold for the U.S. It has examined the potential implications of two primary climate scenarios, each based on the same assumptions about 

future ‘‘business as usual’’ global emissions of greenhouse gases that the IPCC has 

used for many of its analyses. The two climate scenarios were based on output from 

two different global climate models used in the IPCC assessment. They are clearly 

within the range of global annual average temperature changes shown by many 

such models, one near the low and one near the high end of the range. Both exhibit 

warming trends for the U.S. that are larger than the global average (Attachment 

3). This is not surprising. For many years, one of the most robust results of global 

climate models has been that greater warming is expected in more northerly latitudes, and that land surfaces are expected to warm more than the global average. 

We have used assumptions that are entirely consistent with those used by the 

IPCC. 

These climate scenarios describe significantly different futures that are all scientifically plausible, given our current understanding of how the climate system operates. As importantly, they describe separate baselines for analysis of how natural 

ecosystems, agriculture, water supplies, etc. might change as a result. In order to 

investigate such changes, i.e. the potential impacts of climate changes, the report 

relies on up-to-date models, on empirical observations from the literature, on investigations of how these systems have responded to climate variability that has been 

observed over the past century in the U.S., and on the accumulated scientific knowledge that is available about the sensitivities of resources to climate, and about how 

the regions of the U.S. have and potentially could respond. 

One additional important point about the scenarios should be mentioned. The report does not ‘‘merge’’ the results of models that disagree; it explicitly avoids doing 

so. The best example of this is in the analysis of potential changes in precipitation, 

where the two models used to create the scenarios give quite different results for 

some areas of the U.S. We have chosen to highlight these differences and explain 

that regional-scale precipitation projections are much more uncertain compared with 

temperature, rather than attempting to merge the results or guess which is more 

likely. The knowledge that the direction of precipitation change in some areas is 

quite uncertain is valuable for planning purposes, and clearly represents an important research challenge. There is however, consistency among models and observations on other aspects of precipitation changes. For example, both models and observations show an increase in the proportion of precipitation derived from heavy and 

extreme events as the climate warms (Attachment 4). So, both types of information 

are pertinent to help with the identification of potential coping actions. In this respect, the report follows the procedure that the IPCC itself uses for its global impacts reports, each of which examines the potential impacts for entire continents. 

The U.S. national assessment presents the results for each scenario clearly, and 

then takes the important additional step of explicitly describing the NAST’s scientific judgment about the uncertainty inherent in each result. Those results that 

are viewed to be robust are described in more terms; those viewed to be the result 

of poorly understood or unreconciled differences between models are described in 

more circumspect language. The lexicon of terms used to denote the NAST’s greater 

or lesser confidence is explicitly described in the beginning of the Overview report. 

This helps ensure that the report does not mask important results by thoughtlessly 

merging models, or overstating the scientific capability for assessing potential impacts. Finally, the report begins to identify possible options for adaptation to this 

changing world. It does not do a complete analysis of the costs, benefits, or feasibility of these options however, which is a necessary next step for developing policies 

to address these issues. 

The report’s draft key findings (as more fully described in Attachment 5) present 

important observations for all Americans:

1. Increased warming. Assuming continued growth in world greenhouse gas 

emissions, the climate models used in this Assessment project that temperatures in the U.S. will rise 5–10°F (3–6°C) on average in the next 100 years.

2. Differing regional impacts. Climate change will vary widely across the U.S. 

Temperature increases will vary somewhat from one region to the next. 

Heavy and extreme precipitation events are likely to become more frequent, 

yet some regions will get drier. The potential impacts of climate change will 

also vary widely across the nation.

3. Vulnerable ecosystems. Ecosystems are highly vulnerable to the projected rate 

and magnitude of climate change. A few, such as alpine meadows in the 

Rocky Mountains and some barrier islands, are likely to disappear entirely, 

9

while others, such as forests of the Southeast, are likely to experience major 

species shifts or break up. The goods and services lost through the disappearance or fragmentation of certain ecosystems are likely to be costly or impossible to replace.

4. Widespread water concerns. Water is an issue in every region, but the nature 

of the vulnerabilities varies, with different nuances in each. Drought is an important concern in every region. Floods and water quality are concerns in 

many regions. Snowpack changes are especially important in the West, Pacific 

Northwest, and Alaska.

5. Secure food supply. At the national level, the agriculture sector is likely to be 

able to adapt to climate change. Overall, U.S. crop productivity is very likely 

to increase over the next few decades, but the gains will not be uniform across 

the nation. Falling prices and competitive pressures are very likely to stress 

some farmers.

6. Near-term increase in forest growth. Forest productivity is likely to increase 

over the next several decades in some areas as trees respond to higher carbon 

dioxide levels. Over the longer term, changes in larger-scale processes such 

as fire, insects, droughts, and disease will possibly decrease forest productivity. In addition, climate change will cause long-term shifts in forest species, 

such as sugar maples moving north out of the U.S.

7. Increased damage in coastal and permafrost areas. Climate change and the 

resulting rise in sea level are likely to exacerbate threats to buildings, roads, 

power lines, and other infrastructure in climatically sensitive places, such as 

low-lying coastlines and the permafrost regions of Alaska.

8. Other stresses magnified by climate change. Climate change will very likely 

magnify the cumulative impacts of other stresses, such as air and water pollution and habitat destruction due to human development patterns. For some 

systems, such as coral reefs, the combined effects of climate change and other 

stresses are very likely to exceed a critical threshold, bringing large, possibly 

irreversible impacts.

9. Surprises expected. It is very likely that some aspects and impacts of climate 

change will be totally unanticipated as complex systems respond to ongoing 

climate change in unforeseeable ways.

10. Uncertainties remain. Significant uncertainties remain in the science underlying climate-change impacts. Further research would improve understanding 

and predictive ability about societal and ecosystem impacts, and provide the 

public with useful information about adaptation strategies.

Given these findings it is clear that climate impacts will vary widely across the 

Nation, as one would expect for a country as large and ecologically diverse as the 

U.S. Natural ecosystems appear to be highly vulnerable to climate changes of the 

magnitude and rate which appear to be likely; some ecosystems surprisingly so. The 

potential impacts on water resources are an important issue in every region examined, although the nature of the concern is very different for the mountainous West 

than for the East. The potential for drought is a concern across the country. The 

nation’s food supply appears secure, but there are very likely to be regional gains 

and losses for farmers, leading to a more complex picture on a region-by-region 

basis. Forests are likely to grow more rapidly for a few decades because of increasing carbon dioxide concentrations in the atmosphere, but it is unclear whether those 

trends will be maintained as the climate system itself changes, leading to other disturbances such as fire and pest outbreaks. However, the climate change itself will, 

over time, lead to shifts in the tree species in each region of the country, some of 

them potentially quite profound. Coastal areas in many parts of the U.S. and the 

permafrost regions of Alaska are already experiencing disruptions from sea-level 

rise and recent regional warming; these trends are likely to accelerate. Climate 

change will very likely magnify the cumulative impacts of other environmental 

stresses about which people are already concerned, such as air and water pollution, 

and habitat destruction due to development patterns. There are clearly links between human health, current climate, and air pollution. The future vulnerability of 

the U.S. population to the health impacts of climate change depends on our capacity 

to adapt to potential adverse changes. Many of these adaptive responses are desirable from a public health perspective irrespective of climate change. Future assessments need to consider climate change in the context of the suite of environmental 

stresses that we all face. Perhaps most importantly, the report acknowledges very 

clearly that scientific uncertainties remain, and that we can expect surprises as this 

10

uncontrolled experiment with the Earth’s geochemistry plays out over the coming 

decades. 

We hope that the public comment period will indeed result in a broad discussion 

of this draft report. This is, after all, a topic of immense importance and broad significance for Americans. We invite those with the interest to do so to participate by 

obtaining the current draft (www.usgcrp.gov), and to submit their comments, concerns, and criticisms. Our interest is in being as open and transparent as possible 

about what we have concluded, the scientific integrity of the results, and why we 

think they are important for us all.

Attachment 1

National Assessment Synthesis Team Members

Jerry M. Melillo, Co-chair 

Ecosystems Center 

Marine Biological Laboratory

Anthony C. Janetos, Co-chair 

World Resources Institute

Thomas R. Karl, Co-chair 

NOAA National Climatic Data Center

Robert Corell (from January 2000) 

American Meteorological Society and 

Harvard University

Eric J. Barron 

Pennsylvania State University

Virginia Burkett 

USGS, National Wetlands Research 

Center

Thomas F. Cecich 

Glaxo Wellcome, Inc.

Katharine Jacobs 

Arizona Department of Water 

Resources

Linda Joyce 

USDA Forest Service

Barbara Miller 

World Bank

M. Granger Morgan 

Carnegie Mellon University 

Edward A. Parson (until January 2000) 

Harvard University

Richard G. Richels 

EPRI

David S. Schimel 

National Center for Atmospheric 

Research

Additional Lead Authors

David Easterling (NOAA National 

Climatic Data Center)

Lynne Carter (National 

Assessment Coordination Office)

Benjamin Felzer (National Center for 

Atmospheric Research)

John Field (University of Washington)

Paul Grabhorn (Grabhorn Studio)

Susan J. Hassol (Aspen Global 

Change Institute)

Michael MacCracken (National 

Assessment Coordination Office)

Joel Smith (Stratus Consulting)

Melissa Taylor (National Assessment 

Coordination Office) 

Attachment 2

Independent Review Board of the President’s Committee of Advisers on 

Science and Technology (PCAST) 

Peter Raven, Co-chair 

Missouri Botanical Garden and PCAST

Mario Molina, Co-chair 

MIT and PCAST

Burton Richter 

Stanford University

Linda Fisher 

Monsanto

Kathryn Fuller 

World Wildlife Fund

John Gibbons 

National Academy of Engineering

Marcia McNutt 

Monterey Bay Aquarium Research Institute

11

Sally Ride 

University of California San Diego and PCAST

William Schlesinger 

Duke University

James Gustave Speth 

Yale University

Robert White 

University Corporation for Atmospheric Research, and Washington, Advisory Group

Attachment 3


718karl1.eps
12

Simulation of decadal average changes in temperature from leading climate models 

based on historic and projected changes in CO2 and sulfate atmospheric concentrations. The heavy red and black lines indicate the primary models chosen for use by 

the National Assessment. For the 21st century the projected global temperature increase for the Hadley model is 4.9°F and 7.4°F for the Canadian model. The model 

with the smallest projected increase of global temperature is the Climate System 

Model at 3.6°F. By comparison, the projected increase in temperature for the 21st 

century over the contiguous U.S. is: Canadian, 9.4°F; Hadley, 5.5°F; and the Climate System Model, 4.0°F.

Global USA 

Hadley 4.9°F 5.5°F 

Canadian 7.4°F 9.4°F 

CSM 3.6°F 4.0°F 

13

Attachment 4

These graphs of precipitation for the contiguous U.S. show both observed changes 

during the 20th Century and projected changes for the 21st Century based on the 

Canadian Global Climate Model (Version 1) and the Hadley Climate Model (Version 

2). As the charts demonstrate, the largest increases have been and are projected to 

be in the heaviest precipitation events, the days already receiving large amounts of 

precipitation.

Attachment 5

Summary 

Large impacts in some places. The impacts of climate change will be significant for Americans. The nature and intensity of impacts will depend on the location, 

activity, time period, and geographic scale considered. For the nation as a whole, 

direct economic impacts are likely to be modest. However, the range of both beneficial and harmful impacts grows wider as the focus shifts to smaller regions, individual communities, and specific activities or resources. For example, while wheat 

yields are likely to increase at the national level, yields in western Kansas, a key 

U.S. breadbasket region, are projected to decrease substantially under the Canadian 

climate model scenario. For resources and activities that are not generally assigned 

an economic value (such as natural ecosystems), substantial disruptions are likely. 


718karl2.eps
14

Multiple-stresses context. While Americans are concerned about climate change 

and its impacts, they do not think about these issues in isolation. Rather they consider climate change impacts in the context of many other stresses, including landuse change, consumption of resources, fire, and air and water pollution. This finding 

has profound implications for the design of research programs and information systems at the national, regional, and local levels. A true partnership must be forged 

between the natural and social sciences to more adequately conduct assessments 

and seek solutions that address multiple stresses. 

Urban areas. Urban areas provide a good example of the need to address climate 

change impacts in the context of other stresses. Although large urban areas were 

not formally addressed as a sector, they did emerge as an issue in most regions. 

This is clearly important because a large fraction of the U.S. population lives in 

urban areas, and an even larger fraction will live in them in the future. The 

compounding influence of future rises in temperature due to global warming, along 

with increases in temperature due to local urban heat island effects, makes cities 

more vulnerable to higher temperatures than would be expected due to global 

warming alone. Existing stresses in urban areas include crime, traffic congestion, 

compromised air and water quality, and disruptions of personal and business life 

due to decaying infrastructure. Climate change is likely to amplify some of these 

stresses, although all the interactions are not well understood. 

Impact, adaptation, and vulnerability. As the Assessment teams considered 

the negative impacts of climate change for regions, sectors, and other issues of concern, they also considered potential adaptation strategies. When considered together, negative impacts along with possible adaptations to these impacts define 

vulnerability. As a formula, this can be expressed as vulnerability equals negative 

impact minus adaptation. Thus, in cases where teams identified a negative impact 

of climate change, but could not identify adaptations that would reduce or neutralize 

the impact, vulnerability was considered to be high. A general sense emerged that 

American society would likely be able to adapt to most of the impacts of climate 

change on human systems but that the particular strategies and costs were not 

known. 

Widespread water concerns. A prime example of the need for and importance 

of adaptive responses is in the area of water resources. Water is an issue in every 

region, but the nature of the vulnerabilities varies, with different nuances in each. 

Drought is an important concern in every region. Snowpack changes are especially 

important in the West, Pacific Northwest, and Alaska. Reasons for the concerns 

about water include increased threats to personal safety, further reduction in potable water supplies, more frequent disruptions to transportation, greater damage to 

infrastructure, further degradation of animal habitat, and increased competition for 

water currently allocated to agriculture. 

Health, an area of uncertainty. Health outcomes in response to climate change 

are highly uncertain. Currently available information suggests that a range of 

health impacts is possible. At present, much of the U.S. population is protected 

against adverse health outcomes associated with weather and/or climate, although 

certain demographic and geographic populations are at greater risk. Adaptation, primarily through the maintenance and improvement of public health systems and 

their responsiveness to changing climate conditions and to identified vulnerable subpopulations should help to protect the U.S. population from adverse health outcomes 

of projected climate change. The costs, benefits, and availability of resources for 

such adaptation need to be considered, and further research into key knowledge 

gaps on the relationships between climate/weather and health is needed. 

Vulnerable ecosystems. Many U.S. ecosystems, including wetlands, forests, 

grasslands, rivers, and lakes, face possibly disruptive climate changes. Of everything examined in this Assessment, ecosystems appear to be the most vulnerable 

to the projected rate and magnitude of climate change, in part because the available 

adaptation options are very limited. This is important because, in addition to their 

inherent value, they also supply Americans with vital goods and services, including 

food, wood, air and water purification, and protection of coastal lands. Ecosystems 

around the nation are likely to be affected, from the forests of the Northeast to the 

coral reefs of the islands in the Caribbean and the Pacific. 

Agriculture and forestry likely to benefit in the near term. In agriculture 

and forestry, there are likely to be benefits due to climate change and rising CO2

levels at the national scale and in the short term under the scenarios analyzed here. 

At the regional scale and in the longer term, there is much more uncertainty. It 

must be emphasized that the projected increases in agricultural and forest productivity depend on the particular climate scenarios and assumed CO2 fertilization effects analyzed in this Assessment. If, for example, climate change resulted in hotter 

15

and drier conditions than projected by these scenarios, both agricultural and forest 

productivity could possibly decline. 

Potential for surprises. Some of the greatest concerns emerge not from the 

most likely future outcomes but rather from possible ‘‘surprises.’’ Due to the complexity of Earth systems, it is possible that climate change will evolve quite differently from what we expect. Abrupt or unexpected changes pose great challenges 

to our ability to adapt and can thus increase our vulnerability to significant impacts. 

A vision for the future. Much more information is needed about all of these 

issues in order to determine appropriate national and local response strategies. The 

regional and national discussion on climate change that provided a foundation for 

this first Assessment should continue and be enhanced. This national discourse involved thousands of Americans: farmers, ranchers, engineers, scientists, business 

people, local government officials, and a wide variety of others. This unique level 

of stakeholder involvement has been essential to this process, and will be a vital 

aspect of its continuation. The value of such involvement includes helping scientists 

understand what information stakeholders want and need. In addition, the problemsolving abilities of stakeholders have been key to identifying potential adaptation 

strategies and will be important to analyzing such strategies in future phases of the 

assessment. 

The next phase of the assessment should begin immediately and include additional issues of regional and national importance including urban areas, transportation, and energy. The process should be supported through a public-private partnership. Scenarios that explicitly include an international context should guide future assessments. An integrated approach that assesses climate impacts in the context of other stresses is also important. Finally, the next assessment should undertake a more complete analysis of adaptation. In the current Assessment, the adaptation analysis was done in a very preliminary way, and it did not consider feasibility, 

effectiveness, costs, and side effects. Future assessments should provide ongoing insights and information that can be of direct use to the American public in preparing 

for and adapting to climate change.

The CHAIRMAN. Thank you for being here. 

Dr. Janetos. 

STATEMENT OF DR. ANTHONY C. JANETOS, SENIOR VICE 

PRESIDENT FOR PROGRAM, WORLD RESOURCES INSTITUTE 

Dr. JANETOS. Mr. Chairman, thank you for the opportunity to 

discuss the national assessment of potential impacts of climate 

change in the U.S. 

There are really three questions about climate change that have 

dominated many of the public and scientific discussions: first, how 

much climate change is going to occur, second, what might happen 

as a result, and third, what can countries do about it? 

The purpose of the national assessment is to focus only on the 

second of these questions. That is, to address the question of, so 

what, with our best understanding of the underlying science, and 

then to address the questions of major uncertainties in order to 

make well-reasoned recommendations for future research. 

The national assessment was called for in the original enabling 

legislation in 1990 for the U.S. global change research program. In 

1997, Dr. John Gibbons, then Science Advisor to the President, requested the global change research program to undertake the national assessment focusing on understanding other environmental 

stresses and issues within which climate change impacts might 

occur, whether climate change and variability might exacerbate or 

ameliorate existing problems, what options for coping might exist, 

and what research is most important to complete over both the 

short and the longer term. 

A variety of efforts emerged in response to Dr. Gibbons’ charge. 

First was a substantial bottom-up effort. Over 20 workshops were 

16

held around the country, involving a broad range of stakeholders, 

academics, farmers and ranchers, businesspeople, land managers, 

people from every walk of life. 

Each workshop identified a range of issues of concern within 

their regions. Many of these were followed by the initiation of scientific studies, some of which have finished their work and have 

been published, others of which are ongoing. 

At the same time, it was thought to be necessary to create a companion but independent effort to create a national level synthesis 

of what is known for the U.S. as a whole, addressing the issues 

that were raised in workshops, and addressing issues that have 

been raised in national studies of several important sectors. 

This national study was viewed to build on work that has been 

done and published, on the published scientific literature, and on 

analyses that were to be done with the most up-to-date environmental data and models that could be obtained. All sources that 

were used in the national assessment and the national study were 

to be documented and to be available so that this study would 

present the best snapshot at this time of our understanding, using 

the best available information. 

The national assessment synthesis team, which Mr. Karl, Dr. 

Melillo and I co-chair, was chartered under the Federal Advisory 

Committee Act specifically to carry out the national study. Its 

membership is drawn from academic and research institutions 

from industry, from nongovernmental organizations, and government research laboratories. 

The first thing that we did was to publish a plan for the conduct 

of the national synthesis and select five issues for national analysis 

in addition to the work which Tom has just described on the different regions of the U.S. This plan was published in 1998 and has 

been available on the Internet. 

The products of our work is now in two volumes. The first of 

these we call the foundation volume. It is over 600 pages long, with 

more than 200 figures and tables. It is extensively referenced and, 

as I mentioned, we have made the commitment that all of the 

sources, of which there are thousands used in it, are documented 

and are available. These are basically the same guidelines as the 

Intergovernmental Panel on Climate Change has used for the accessibility of source material. 

The second volume we have called the overview. It is written 

more in a style for the general public. It is substantially shorter, 

about 150 pages long and extensively illustrated, and is a summary 

of the foundation document. 

Both of these volumes have already undergone significant review. 

At the end of 1999 and the beginning of this year we went through 

two rounds of technical peer review. Subsequent to that, this past 

spring we went through an additional review by about 20 independent experts. We have received over 300 sets of comments and 

have made a commitment to document our responses to external 

comments that we have received. 

In addition, we have written an overview memo summarizing our 

responses to major comments. We are now approximately half-way 

through a 60-day public comment period that was specifically requested by the Congress. When it ends, we anticipate responding 

17

to the additional comments we will have received, as we have done 

before, and putting the report in final form in order to be submitted to the President and Congress, as called for in the original 

legislation. 

Throughout, the national assessment synthesis team has been 

the beneficiary of oversight review and guidance from an oversight 

panel which was established through the offices of the President’s 

Council of Advisors on Science and Technology, chaired by Dr. 

Peter Raven and Dr. Mario Melina. 

One thing I would like to emphasize in closing is that it is important to remember that the national assessment does not attempt 

to predict exactly what the future will hold for the U.S. It has examined the potential implications of two primary climate scenarios, 

but has used many other data sets as well. That is, it uses our best 

scientific understanding of ecosystems, hydrologic systems, agriculture, forestry, and so on, to explore the different consequences 

of scientifically plausible futures. 

We explicitly discuss uncertainty in the underlying science. In 

fact, throughout the assessment we have consistently used language describing our scientific confidence in the results and findings so that the reader can understand when we are very confident 

of our findings and when we are less so. 

Thank you very much. 

The CHAIRMAN. Thank you very much. Dr. Schmitt. 

STATEMENT OF DR. RAYMOND W. SCHMITT, SENIOR 

SCIENTIST, WOODS HOLE OCEANOGRAPHIC INSTITUTIONS 

Dr. SCHMITT. Thank you, Mr. Chairman. I am a physical oceanographer. In the past 25 years I have averaged about 1 month a 

year at sea on research cruises. In the past 10 years I have averaged about 1 month a year working on committees concerned with 

the role of the oceans in climate. 

The thrust of my statement is that the oceans have a very important role to play in climate, and that we are not doing a very good 

job at either modeling the role of the oceans in climate predictions, 

nor are we properly monitoring the state of the ocean in order to 

make these predictions possible. 

In the past few years oceanographers have done a large-scale 

survey of the state of the world ocean. We called it the World 

Ocean Circulation Experiment. It was funded by the National 

Science Foundation, and what we found was quite interesting. 

In most areas—not all, but in most areas, deep waters had 

warmed significantly since the last time a major survey had been 

done in the fifties, so we are seeing global warming in the ocean. 

It is real, and we are finding it in the ocean and, in fact, the fact 

that we find it so deep in the ocean has been a surprise for many 

climate modelers, because the models they use have a very slow responding ocean. It is more like lava or concrete than the water that 

we know. 

So oceanographers have a very different view of the ocean. We 

see a more active agent of climate change. 

The CHAIRMAN. Why would it warm in——

Dr. SCHMITT. So deep? 

The CHAIRMAN. Yes. 

18

Dr. SCHMITT. Well, it is quite interesting. The ocean interacts 

with the atmosphere at high latitudes, and the water can sink 

quite deeply. Up in the Labrador Sea, up in the seas off Greenland 

and Iceland, we call this deep convection, and this deep convection 

is how the ocean changes temperature, how it gives heat to the atmosphere and changes its own internal temperature, and this 

whole process—we call it the thermohaline circulation—is very important to transporting heat to high latitudes, for keeping Europe 

warm. The fact that England has a very moderate climate is due 

to this thermohaline circulation. 

Well, one of the very exciting things that the paleoceanographers 

have found is that this circulation shut off at times in the past, 

when that water got too fresh. At the end of the last glaciation, 

about 12,000 years ago, there was a lot of fresh water coming from 

the melting glaciers. It shut off thermohaline circulation because 

adding fresh water makes the water lighter and it cannot sink, so 

then no heat was carried northward, Europe got very cold, and the 

ice ages came back for about 1,000 years. 

The striking thing is that this change happened in a couple of 

decades, in the data that they have obtained from the ice core and 

in the sedimentary record at the bottom of the ocean. Some climate 

models predict an increase in high latitude rainfall due to the global warming. Warm air carries more water than cold air, and they 

have projected a shutdown in this thermohaline circulation. That 

would be a very significant change that could occur very rapidly. 

Now, the other thing that we found in the last few years is that 

the ocean has certain temperature patterns that lock in specific climate phenomena. We all know about El Nin ̃ o and la nin ̃ a. That is 

warm water sloshing back and forth in the Pacific. Well, there is 

another oscillation called the North Atlantic oscillation, that seems 

to be controlled by the patterns of warm water moving around the 

North Atlantic. 

We are at the stage technologically where we can make better 

measurements of these deep temperature patterns in the ocean 

with autonomous probes, floats that are like weather balloons for 

the ocean. They drift at depth, they inflate a small bladder every 

10 days, come to the surface and obtain a profile of temperature 

and salinity on the way up, send that data to a satellite, and then 

resubmerge for another 10-day drift. 

From this we get the heat content of the ocean, we find out its 

salt content, and therefore whether it is likely to continue deep 

convecting in the winter. These things will help us to gain the ability to predict climate for 5 to 10 years in advance. We find this a 

very exciting research possibility. 

The CHAIRMAN. What are you finding out? 

Dr. SCHMITT. Well, the hope that we are holding out is that when 

we have enough data coming in from these new observation systems, and enough understanding of these processes, that we will be 

able to predict climate with greater confidence than we have now. 

Right now there is a great deal of uncertainty about all of these 

modes of operation. 

The CHAIRMAN. When will you be able to start making these predictions? 

19

Dr. SCHMITT. Prediction is a dangerous game. There is a program 

called Argo we are trying to get funded. 

The CHAIRMAN. Yes. 

Dr. SCHMITT. We hope to have that in place in full operation in 

about 5 years, and I would think it would really start to have a 

significant effect on climate predictions 5 years from now. 

That is the basic thrust of my statement, and I thank you for the 

opportunity to present this to the Committee. 

[The prepared statement of Dr. Schmitt follows:]

PREPARED STATEMENT OF DR. RAYMOND W. SCHMITT, SENIOR SCIENTIST, WOODS HOLE OCEANOGRAPHIC INSTITUTIONS

The Ocean’s Role in Climate 

My name is Raymond Schmitt, I am a Senior Scientist in the Department of Physical Oceanography at the Woods Hole Oceanographic Institution. My research interests include the ocean’s role in climate, small-scale mixing processes, the global 

water cycle, and instrumentation for a global ocean observing system. I have served 

on a number of national and international committees concerned with climate, including the Atlantic Climate Change Program Science Working Group, the Ocean 

Observing System Development Panel, and the Climate Variability (CLIVAR) 

Science Steering Group, and am a contributing author to the IPCC Third Assessment Report. 

The thrust of my comments today is that the crucial role of the oceans in climate 

has not been sufficiently acknowledged in most research on climate change to date, 

including the National Climate Assessment Report under discussion here. It was a 

tradition of the climate modeling community to treat the ocean as a shallow swamp; 

a source of moisture but playing no role in heat transport and storage. We now 

know this to be a significant error, the oceans are an equal partner with the atmosphere in transporting heat from the equator to the poles, and a reservoir of heat 

and water that overwhelmingly dwarfs the capacity of the atmosphere. 

A few facts about 

The Oceans: 

Cover 70% of the surface of the Earth.

Have 1,100 times the heat capacity of the atmosphere 

(99.9% of the heat capacity of the Earth’s fluids)

Contain 90,000 times as much water as the atmosphere 

(97% of the free water on the planet)

Receive 78% of global precipitation

A quote from Arthur C. Clarke gets it right:

‘‘How inappropriate to call this planet Earth when clearly it is Ocean’’—Nature, v. 

344, p. 102, 1990.

New evidence for the essential role of the oceans in climate is coming out of the 

recent World Ocean Circulation Experiment (WOCE), supported by the National 

Science Foundation. A globe-spanning set of ship-based observations in the ’90s revealed that the depths of the ocean had warmed significantly since previous observations in the ’50s. In fact, about half the ‘‘missing’’ greenhouse warming has been 

found in the ocean. It was missing because models had projected a larger increase 

than had been observed. It now appears this was because they had not properly accounted for the capacity of the oceans to store large quantities of heat on short 

timescales. In fact, it is easy to calculate that if all of the extra heat due to the 

greenhouse change in the radiation balance were to be deposited in the deep ocean, 

it would take 240 years for it to rise 1°C. Thus, monitoring the ocean’s patterns of 

heat storage is absolutely essential for understanding global warming, yet we have 

no system for such observations. 

But the oceans do more than simply delay global warming. Research over the past 

twenty years has brought a growing appreciation of how the slow movement of 

warm and cold patches of ocean water can affect our weather for months at a time. 

The alternating influence of El Nin ̃ o and la nin ̃ a are now well known to the public 

and are rashly blamed for any type of unusual weather. These 3–5 year period disVerDate Apr 24 2002 08:33 Sep 05, 2003 Jkt 083037 PO 00000 Frm 00023 Fmt 6633 Sfmt 6621 S:\WPSHR\GPO\DOCS\83037.TXT SCOM2 PsN: JACKF
20

ruptions in weather patterns are caused by the movement of warm water in the 

tropical Pacific, and are now predictable up to a year in advance because of a special 

monitoring network of ocean buoys maintained there. The influence of El Nin ̃ o on 

U.S. weather is well publicized, but it actually explains only a small part of the variation in temperature and rainfall over the United States. Some other natural ocean 

climate cycles known as the Pacific Decadal Oscillation (PDO) and the North Atlantic Oscillation (NAO) can explain much more of the variability in winter-time weather than El Nin ̃ o. (Figure 1.). The NAO in particular has much more impact on the 

eastern half of the United States than El Nin ̃ o. 

Exciting new findings suggest that the ocean controls the timescale of the NAO, 

thus holding out the hope that these weather patterns will be predictable when sufficient ocean observations become available.

Figure 1. The correlation of U.S. winter-time climate with El Nin ̃ o, PDO and NAO 

over a 35 year period. If we could predict these phenomena in advance, then the 

square of the numbers represented by the colors gives the winter climate variability 

that is potentially predictable. That is, white areas would have no predictability, but 

in the brown areas 36% or more of winter climate changes could be predicted. However, we do not yet have predictive capabilities for PDO or NAO. If predictions are 

to be made we will require a greatly expanded ocean observing system.


718schm1.eps
21

Recent research indicates that the NAO’s changes in atmospheric pressure patterns over the Atlantic are linked to the slow variation in water temperatures, as 

the ocean currents rearrange the warm and cold ocean patterns that serve to guide 

the atmosphere in its preferred modes of oscillation. Only the ocean has the longterm memory to provide the decadal time scales observed in the NAO. An understanding of these natural modes of climate variation is essential for accurate predictions of the regional trends in U.S. climate. That the two models examined in 

the Climate Assessment report should differ so widely in prediction of future U.S. 

precipitation is no surprise. Models are only a repository for what we think we 

know, and an understanding of the important oceanic phenomena such as PDO and 

NAO has not yet been achieved. In order to understand these phenomena we need 

to observe the motion of the deep warm and cold patches that give the ocean its 

multi-decadal memory, and we need to sustain those observations through a few cycles of the oscillations. In contrast to the 1,200 records of U.S. land temperature 

used to examine climate trends in the report, we have only three sites with anything like a continuous deep record in all of the North Atlantic! For these few sites 

with rather short records, an observation once a month is often the best we have. 

This observation system is woefully inadequate. It is obvious that the ocean is the 

long-term memory of the Earth’s climate system yet we persist in ignoring it. Some 

think it sufficient to look at the surface of the ocean with a satellite and try to 

model the interior. However, satellites can tell us nothing about the deep interior 

temperatures that influence winter-time climate.

Figure 2. The North Atlantic Oscillation (NAO). Its ‘‘high index’’ state is shown on 

the left, this corresponds to particularly high atmospheric pressure over the Azores, 

an intense low over Iceland. Ocean winds are stronger and winters milder in the 

eastern U.S. When the NAO index is low, ocean winds are weaker and the U.S. winter more severe. Changes in ocean temperature distributions are also observed.

The Water Cycle and Thermohaline circulation 

Also, satellites can tell us nothing about the salt content of the ocean, which reflects the workings of the water cycle. There is an increasing attention to the importance of the water cycle in global change; for most communities drought or flood are 

more pressing challenges than a few degrees of warming. However, there has been 

little recognition that most of the water cycle occurs over the oceans. It would take 

a diversion of only 1% of the rainfall falling on the Atlantic to double the discharge 

of the Mississippi River. Water travels quickly through the atmosphere, spending 

only about 10 days on a short ride from one spot to another. Water molecules spend 

thousands of years on the slow return flow in the ocean. But the process of water 

leaving the surface of the ocean, and thereby changing its salt content and density, 

drives an interior flow many times larger than the flux of water due to evaporation 

and precipitation alone. This ‘‘thermohaline circulation’’ is a key element of the climate system, as it is responsible for most of the ocean’s heat transport from equator 

to pole. When salty water gives up its heat to the atmosphere, it can become dense 

enough to sink to the bottom of the ocean, thereby keeping making room for more 

warm water to come north for cooling. The North Atlantic is the saltiest ocean and 


718schm2.eps
22

the most active site for such ‘‘deep convection’’. However, if it becomes too fresh from 

rainfall the surface waters cannot sink and the flow of warm water stops.

Figure 3. The influence of salt content (salinity) on the process of deep convection. 

Normally, winter cooling at the surface causes deep vertical mixing which releases 

much heat to the atmosphere (left). When fresher water lies at the surface because 

of rain fall or ice melt, the deep convection is prevented and only a shallow surface 

layer provides heat to the air above (right). Thus, salinity is now considered a key 

variable for climate studies.

Records from ocean sediments of the fossils of marine life indicate that this has 

happened many times in the past, with dramatic consequences for climate over a 

large area. The most recent event was about 12,000 years ago, when the freshwater 

from melting glaciers shut down the thermohaline circulation in the North Atlantic. 

This had dramatic consequences for the North Hemisphere, returning much of it to 

glacial conditions for 1000 years. The data indicate that this happened rapidly, in 

only a decade or two. Some models predict that such abrupt climate change could 

happen again as the water cycle intensifies with future global warming. However, 

such transitions in the thermohaline circulation have been shown to depend on the 

rate of interior mixing in the ocean, and we know that this is incorrectly treated 

in the present generation of climate models. 

Model Deficiencies 

In fact, oceanographers have many complaints about how poorly climate models 

simulate the ocean. Because of computer limitations, they must treat it as a very 

viscous fluid, more like lava or concrete than water. Such models fail to simulate 

the real ocean’s changes in deep temperatures. We know that the ‘‘sub-grid-scale’’

parameterizations for mixing processes are incorrect, reflecting none of the observed 

spatial variations or differences between heat and salt. This mixing drives the interior flows in the ocean. We know that the processes by which ocean currents give 

up their momentum are incorrectly treated. And these are not problems that will 

quickly yield to increased spatial and temporal resolution in the computer models. 

Even if computer power continues to increase by an order of magnitude every 6 


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1 It will take a factor of 108 improvement in 2 horizontal dimensions (100 km to 1 mm, the 

salt dissipation scale), a factor of 106 in the vertical dimension (∼10 levels to 107) and ∼105 in 

time (fraction of a day to fraction of a second); an overall need for an increase in computational 

power of ∼1027. With an order of magnitude increase in computer speed every 6 years, it will 

take 162 years to get adequate resolution in computer models of the ocean.

years, it will be over 160 years 1 before models have the resolution necessary to simulate the smallest ocean mixing processes! Society cannot afford to wait that long. 

We will not come to an understanding of climate by more computational cycles of 

models with incorrect physics. We require a systematic study of the sub-grid-scale 

processes in the ocean. This is noticeably lacking in our current Global Change Research Program. 

Figure 4. The operation of a profiling float for the ARGO program. These autonomous probes can provide unprecedented amounts of data from the interior ocean at 

a modest cost. Knowledge of the interior ocean temperature is necessary because 

these waters interact with the atmosphere every winter through the process of deep 

convection.

Observing Deficiencies 

While we have in place a system for monitoring El Nin ̃ o, we have no such ability 

to observe the motions of thermal anomalies in the mid- and high-latitude oceans. 

Nor do we monitor the salt content of ocean currents, to determine the potential for 

deep convection or to help understand the vast water cycle over the oceans. But new 

technology, the vertically profiling ARGO float (Figure 4.), promises to give us the 

data we need to begin to understand this largest component of the global water 

cycle. These are like weather balloons for the ocean, drifting at depth for 10 days 

then rising to the surface to report profiles of temperature and salinity to a satellite. 


718schm4.eps
24

They then resubmerge for another 10 day drift, a cycle to be repeated 150 times 

or more. The distance traveled between surfacings provides a measure of the currents at the depth of the drift. The ARGO program (http://www.argo.ucsd.edu/) is 

an international plan to maintain a global distribution of ∼3000 floats as a core element of a Global Ocean Observing System (Figure 5.). Other parts of the system 

involve fixed sites with moored buoys and underwater profilers that record temperature and salinity all the way to the bottom of the ocean. These new technologies 

will give us the data we need to begin to decipher the complex climate phenomena 

we know to be operating in the ocean. Science is the process of testing ideas against 

observations, and failure to make the observations is an abandonment of the scientific process.

Figure 5. The surface salinity of the global ocean is represented by the colors, with 

red being the saltiest and blue/purple the freshest. 3000 random dots, representing 

possible ARGO float positions, are seen to provide good sampling of the large-scale 

patterns of salinity variation. The Atlantic Ocean is seen to be saltiest, which helps 

explain why deep convection is especially likely there, and its important role in the 

thermohaline circulation.

What Can Congress Do? 

1. Support fundamental research into the processes that govern the ocean’s role 

in climate. This includes the basic oceanic research programs at NSF and 

ONR, and international programs like CLIVAR. 

2. Make a substantial and long-term commitment to the creation of a Global 

Ocean Observing System. Fund the ARGO program at NOAA (Ocean Observations component of Climate Observations and Services) and the ocean observing satellites of NASA. 

Summary: 

Policy makers would like climate scientists to produce firm predictions. However, 

they must always remember that science is the process of testing ideas against facts 

and access to quantitative data is essential to the process. The ocean is a crucial 

element of the climate system, yet its ‘‘subgrid-scale’’ processes are too poorly understood and its basic structure too poorly monitored, to provide much confidence in 

the details of present day predictions. The National Climate Assessment Report is 

a good faith effort to assess the effects of global warming on U.S. climate; the regional disagreements of the two available models are to be expected, given our poor 


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25

understanding of the ocean. Global warming due to the effect of greenhouse gases 

on the radiation balance is as certain as the law of gravity, but the issues of how 

rapidly heat is sequestered in the oceans, its impact on the water cycle, and the important regional variations in climate, remain very challenging research questions. 

Climate prediction is a hard problem, but appears to be tractable. An abundance 

of evidence indicates that the key to long-term prediction is in the workings of the 

ocean, which has 99.9% of the heat capacity of Earth’s fluids. It is the heart of the 

climate ‘‘beast,’’ the atmosphere its rapidly waving tail, with only 0.1% of the heat 

capacity. Let us get to the heart of the matter, with an unprecedented new look at 

the ocean. We have the technical capabilities. The cost is modest. The payoff is 

large. The society that understands long-term climate variations will realize tremendous economic benefits with improved predictions of energy demand, water resources and natural hazards, and it will make wiser decisions on issues affecting 

the habitability of the planet, such as greenhouse gas abatement.

The CHAIRMAN. Thank you very much. Dr. Singer. 

STATEMENT OF DR. S. FRED SINGER, PROFESSOR EMERITUS 

OF ENVIRONMENTAL SCIENCES, UNIVERSITY OF VIRGINIA, 

AND FORMER DIRECTOR OF U.S. WEATHER SATELLITE 

SERVICE 

Dr. SINGER. Mr. Chairman, I have researched and published 

mainly in atmospheric and space physics over the last years. 

I am professor emeritus of environmental sciences at the University of Virginia, and president of the Science and Environmental 

Policy Project, which is a nonprofit, nonpartisan research group of 

scientists. We all work pro bono, without salary, and we do not solicit money from industry or government, so we are fairly independent. We speak our minds on many issues as we see fit. We are 

mainly interested in making sure that the science underlying the 

various policies, environmental policies is correct and sound. 

The reason I have a skeptical view on the climate science underlying the assessment is because it does not fit with the evidence. 

My testimony concerns just three pieces of evidence, which I will 

briefly outline. 

The first statement I make is that there is no appreciable climate 

warming today. I repeat, there is no appreciable climate warming. 

This puts me at odds with many of my colleagues, I realize that, 

including my distinguished colleague, Tom Karl, but I hope that I 

can convince him and others that the evidence supports what I 

have to say. 

I think the evidence that the climate has not warmed in the last 

2 decades is overwhelming. I have four pieces of evidence. The 

weather satellites, with which I am very familiar, do not show any 

appreciable warming of the atmosphere in the last 20 years. In 

fact, if you take out 1998, the El Nin ̃ o year, there is even a slight 

cooling of the atmosphere in the last 20 years. 

There has been long debate about this, but fortunately the National Research Council of the National Academy of Sciences has 

published a report this year in which they essentially endorse the 

satellite data, and the fact that the atmosphere has not warmed in 

the last 20 years. 

Weather balloons carrying radios get exactly the same result, 

and these are independent measurements of the atmosphere. They 

also show no appreciable warming in the last 20 years. 

The third piece of evidence is the temperature record for the 

United States as produced by NOAA and also published by NASA. 

26

The temperature record for the United States shows that the temperature has not warmed appreciably since about 1940. 

Now, the thermometers do show a global warming. It means that 

there must be warming going on somewhere outside of the United 

States, and outside of Western Europe, because neither one of 

those two networks shows any appreciable warming. 

This is very puzzling, and it is possible that the thermometers 

are not giving correct readings, or that they are contaminated in 

some way. The warming seems to occur mainly in Northwestern Siberia and in subpolar regions of Alaska and Canada. But when one 

checks proxy data, like tree rings, ice cores, and things of that sort, 

which also are a way of measuring temperature, they show no 

warming since 1940, so the thermometer data that do show a 

warming are the odd man out, and we need to do the necessary research to find out why that is. 

As of now, I would say that there is no appreciable warming in 

the last 20 years and, by the way, if there is no warming in the 

last 20 years, this means that this is not the warmest century in 

the last 1,000 years. In fact, we believe it was warmer 1,000 years 

ago than it is today. And this is not the warmest decade in the last 

1,000 years, either. 

So you see, we have a chance here to have a good debate on these 

issues, but this is probably more appropriate for the American Meteorological Society meetings that we are going to be attending 

soon. 

My second point relates to the regional changes in temperature, 

precipitation, and soil moisture. After all, this is the important 

thing, because all of the impacts of climate change are based on 

what is actually happening in the region. My belief is, and I believe 

everyone would agree, that to predict regional changes is beyond 

the state-of-the-art of climate models. 

Climate models cannot even predict properly the global changes, 

but to predict regional changes is practically impossible, and we 

have proof of that. The proof is actually in the report itself, the report that Dr. Janetos has just referred to. The two climate models 

that are used in the report give opposite results in 9 of the 18 regions that have been studied. 

For example, when it comes to rainfall the report shows the Dakotas losing 85 percent of their current rainfall in one model, while 

the second model shows a gain of 75 percent. These opposite results occur in 9 cases out of 18, and in some other cases the results 

show a huge difference. 

The same is also true with soil moisture. The Canadian model 

that was used predicts a drier Eastern United States. The British 

model that was used predicts a wetter Eastern United States. 

So we conclude that the model results are not credible, and 

therefore we believe that the conclusions that are drawn about the 

impact of these climate changes are interesting exercises but 

should not be taken too seriously. 

My third point: I want to discuss sea level rise. Sea level rise is 

widely feared, but also very much misunderstood. Most people 

think the sea level rose in the last century because temperatures 

rose in the last century. That is not so. Sea level has been rising 

for about 15,000 years. Sea level rose by 400 feet in the last 15,000, 

27

and the reason it rose is because the ice melted at the end of the 

last Ice Age. 

First, the ice melted in North America and Northern Europe, and 

that caused a very rapid rise in sea level. We can actually measure 

it. It is about 80 inches per century, as measured. 

Once that ice was gone, the melting slowed down. But the melting still continues, though, in the Antarctic, but now it is the West 

Antarctic ice sheet that is melting slowly, and has been melting for 

15,000 years, and this slow melting of the West Antarctic ice sheet 

amounts to about 7 inches per century of sea level rise. 

This is the sea level rise that is going on right now. This will 

continue for another 6,000 years, unless another Ice Age intervenes. But assuming that we do not get another Ice Age, we will 

have sea level rise going on for another 6,000 years no matter what 

we do. 

We cannot affect this in any way. We cannot stop the tides, we 

cannot stop continental drift, we cannot stop the Antarctic ice sheet 

from melting. It is just going to continue its slow-melting process. 

It has to do with the fact that it is warmer now than it was 15,000 

years ago. 

Finally: The bottom line of all of this is that the scientific evidence does not support the results of the National Assessment. It 

also tells us that we should be doing serious research on both atmospheric and oceanic processes, and that this research needs to 

be carried out much further before we can have confidence in any 

assessment report. 

My conclusion: The National Assessment should definitely not be 

used to justify any irrational or unscientific energy and environmental policies, and that advice I think is particularly relevant to 

the forthcoming Presidential debates and campaigns. 

Thank you very much. 

[The prepared statement of Dr. Singer follows:]

PREPARED STATEMENT OF DR. S. FRED SINGER, PROFESSOR EMERITUS OF ENVIRONMENTAL SCIENCES, UNIVERSITY OF VIRGINIA, AND FORMER DIRECTOR OF U.S. 

WEATHER SATELLITE SERVICE

Mr. Chairman, Ladies and Gentlemen,

My name is Fred Singer. I am Professor Emeritus of Environmental Sciences at 

the University of Virginia and the founder and president of The Science & Environmental Policy Project (SEPP) in Fairfax, Virginia, a non-partisan, non-profit research group of independent scientists. We work without salaries and are not beholden to anyone or any organization. SEPP does not solicit support from either government or industry but relies on contributions from individuals and foundations. 

We hold a skeptical view on the climate science that forms the basis of the National Assessment because we see no evidence to back its findings; climate model 

exercises are NOT evidence. Vice President Al Gore keeps referring to scientific 

skeptics as a ‘‘tiny minority outside the mainstream.’’ This position is hard to maintain when more than 17,000 scientists have signed the Oregon Petition against the 

Kyoto Protocol because they see ‘‘no compelling evidence that humans are causing 

discernible climate change.’’

Others try to discredit scientific skeptics by lumping them together with fringe 

political groups. Such ad hominem attacks are deplorable and have no place in a 

scientific debate. To counter such misrepresentations, I list here qualifications relevant to today’s hearing. 

Relevant Background 

I hold a degree in engineering from Ohio State and a Ph.D. in physics from 

Princeton University. For more than 40 years I have researched and published in 

28

1 National Research Council. ‘‘Reconciling Temperature Trends.’’ National Academy Press, 

Washington, DC. January 2000. 2 R. Kerr. ‘‘Dueling Models: Future U.S. Climate Uncertain.’’ Science 288, 2113, 2000. 3P.H. Stone. ‘‘Forecast Cloudy: The Limits of Global Climate Models.’’ Technology Review

(MIT), Feb/March 1992. pp. 32–40. 

atmospheric and space physics. I received a Special Commendation from President 

Eisenhower for the early design of satellites. In 1962, I established the U.S. Weather Satellite Service, served as its first director, and received a Gold Medal award 

from the Department of Commerce for this contribution. 

Early in my career, I devised instruments to measure atmospheric parameters 

from satellites. In 1971, I proposed that human production of the greenhouse gas 

methane, through cattle raising and rice growing, could affect the climate system. 

This was also the first publication to discuss an anthropogenic influence on stratospheric ozone. In the late 1980s, I served as Chief Scientist of the Department of 

Transportation and also provided expert advice to the White House on climate 

issues. 

Today, by presenting evidence from published peer-reviewed work, I will try to 

rectify some erroneous claims advanced at the May 17 NACC hearing. 

1. There Is No Appreciable Climate Warming 

Contrary to the conventional wisdom and the predictions of computer models, the 

Earth’s climate has not warmed appreciably in the past two decades, and probably 

not since about 1940. The evidence is abundant. 

a) Satellite data show no appreciable warming of the global atmosphere since 

1979. In fact, if one ignores the unusual El Nin ̃ o year of 1998, one sees a cooling 

trend. 

b) Radiosonde data from balloons released regularly around the world confirm the 

satellite data in every respect. This fact has been confirmed in a recent report of 

the National Research Council/National Academy of Sciences.1

c) The well-controlled and reliable thermometer record of surface temperatures for 

the continental United States shows no appreciable warming since about 1940. The 

same is true for Western Europe. These results are in sharp contrast to the GLOBAL instrumental surface record, which shows substantial warming, mainly in NW 

Siberia and subpolar Alaska and Canada. 

d) But tree-ring records for Siberia and Alaska and published ice-core records that 

I have examined show NO warming since 1940. In fact, many show a cooling trend. 

Conclusion: The post-1980 global warming trend from surface thermometers is not 

credible. The absence of such warming would do away with the widely touted ‘‘hockey stick’’ graph (with its ‘‘unusual’’ temperature rise in the past 100 years); it was 

shown here on May 17 as purported proof that the 20th century is the warmest in 

1000 years. 

2. Regional Changes in Temperature, Precipitation, and Soil Moisture? 

The absence of a current global warming trend should serve to discredit any predictions from current climate models, including the extreme warming from the two 

models (Canadian and British) selected for the NACC. 

Furthermore, the two NACC models give conflicting predictions, most often for 

precipitation and soil moisture.2,3 For example, the Dakotas lose 85% of their current average rainfall by 2100 in one model, while the other shows a 75% gain. Half 

of the 18 regions studied show such opposite results; several others show huge differences. 

The soil moisture predictions also differ. The Canadian model shows a drier Eastern U.S. in summer, the UK Hadley model a wetter one. 

Conclusion: We must conclude that regional forecasts from climate models are 

even less reliable than those for the global average. Since the NACC scenarios are 

based on such forecasts, the NACC projections are not credible. 

3. Sea Level Rise: Controlled by Nature not Humans 

The most widely feared and also most misunderstood consequence of a hypothetical greenhouse warming is an accelerated rise in sea levels. But several facts 

contradict this conventional view: 

a) Global average sea level has risen about 400 feet (120 meters) in the past 

15,000 years, as a result of the end of the Ice Age. The initial rapid rise of about 

200 cm (80 inches) per century gradually changed to a slower rise of 15–20 cm (6–

8 in)/cy about 7500 years ago, once the large ice masses covering North America and 

North Europe had melted away. But the slow melting of the West Antarctic Ice 

Sheet continued and will continue, barring another ice age, until it has melted away 

in about 6000 years. 

29

4S.F. Singer. Hot Talk, Cold Science: Global Warming’s Unfinished Debate. (The Independent 

Institute, Oakland, CA. (second edition, p. 18)). 5Office of Technology Assessment. ‘‘Preparing for an Uncertain Climate.’’ Govt. Printing Office, Washington, DC. 1993. 6S.F. Singer. ‘‘Climate Policy—From Rio to Kyoto: A Political Issue for 2000—and Beyond.’’ Hoover Institution Essay in Public Policy No. 102. Stanford, CA, 2000.

b) This means that the world is stuck with a sea level rise of about 18 cm (7 in)/

yr, just what was observed during the past century. And there is nothing we can 

do about it, any more than we can stop the ocean tides. 

c) Careful analysis shows that the warming of the early 1900s actually slowed this 

ongoing SL rise,4 likely because of increased ice accumulation in the Antarctic. 

The bottom line: Currently available scientific evidence does not support any of 

the results of the NACC, which should therefore be viewed merely as a ‘‘what if’’ exercise, similar to the one conducted by the Office of Technology Assessment in 

1993.5 Such exercises deserve only a modest amount of effort and money; one should 

not shortchange the serious research required for atmospheric and ocean observations, and for developing better climate models. 

The NACC should definitely NOT be used to justify irrational and unscientific energy and environmental policies, including the economically damaging Kyoto Protocol. These policy recommendations are especially appropriate during the coming 

presidential campaigns and debates. I respectfully request that an expanded exposition 6 be made part of my written record. [The Executive Summary is in the appendix, the whole document can be found at: //www hoover.stanford.edu/publications/epp/102/102complete.pdf] 

The CHAIRMAN. Thank you, Dr. Singer. In other words, you reject 

the findings of the Assessment practically in its entirety. 

Dr. SINGER. I think these are interesting exercises, what-if exercises, but I do not think they should be taken seriously. 

The CHAIRMAN. Dr. Schmitt, in the climate change you have 

noted in your findings, what is the impact on the ecology of the 

oceans, such as the effect on reef life, et cetera? 

Dr. SCHMITT. Well, I am hardly an expert, but there are very significant impacts on fisheries. I know the cod fishery in New England has changed a lot. It is difficult to sort out whether it is due 

to overfishing or just changes in the North Atlantic Oscillation, because the water off Labrador is so much colder now than it was 10, 

15 years ago. 

In other areas warming in tropical areas has a great impact on 

the life of corals. There is a phenomenon called coral bleaching, 

which basically kills a coral reef, and I believe that occurs if the 

water gets too warm. In other areas the stocks of salmon have been 

correlated with these climate phenomenon such as the North Atlantic Oscillation and the Pacific Decadal Oscillation. 

These phenomena, with their long time scales—they are 5, 10, 15 

year cycles—hold out the hope of predictability because the ocean 

has this long memory of the heat content. It has enormous heat 

content. It has 99.9 percent of the heat content of the climate system, and we need to be doing a much better job on monitoring that 

heat content. 

The CHAIRMAN. Mr. Karl, do you have a response to Dr. Singer’s 

views? 

Mr. KARL. Yes. I have—I do not know where to begin, to be quite 

honest. 

Dr. SINGER. Just start anywhere. 

Mr. KARL. I guess I would first point out that what we did in the 

assessment was draw on the published referenced literature. In 

fact, I think if you look at the references in the assessment there 

is—probably over 95 percent are from papers that have been peerVerDate Apr 24 2002 08:33 Sep 05, 2003 Jkt 083037 PO 00000 Frm 00033 Fmt 6633 Sfmt 6601 S:\WPSHR\GPO\DOCS\83037.TXT SCOM2 PsN: JACKF
30

reviewed. The other 5 percent are reports that often were used because we needed to obtain the data from those reports. 

What I would just want to point out is that the position of Dr. 

Singer, although I very much respect his opinions, is quite at odds 

with the scientific published literature. I would just point out a few 

egregious examples of what I have heard. 

50 percent of the rise, or more than half of the rise in sea level 

is due to the expansion of ocean waters. As temperatures increase, 

the ocean density increases, and it has nothing to do with the melting of ice glaciers. 

The other aspects that I heard which I would completely disagree 

with, and that is the warming in the U.S. record. It is very clear, 

in fact, especially in the last decade or two, the U.S. was lagging 

behind global temperature increases up till the early 1980’s, and 

since the mid-1980’s, and particularly during the 1990’s, the U.S. 

has virtually captured the rest of the globe. 

That is not to be unexpected. In fact, if you look at one area in 

the country, the Southeast part of the U.S., it is where we have not 

seen much of an increase in temperature. In fact, there have been 

very small changes in temperature, but again if you look at the 

1990’s in the Southeast, we are almost now as warm as we were 

back in the 1930’s. 

And again, I might point out that in the Arctic we have had 

record low ice extents in the Arctic. In fact, if you look at the latest 

IPCC report that is up for review, it is documented that we also 

see reduced snow cover extending across the northern hemisphere. 

So it is not just the temperature records that we use to deduce 

the fact that the globe is warming. There are many, many other 

ancillary pieces of information that are used as well. 

So those are just a few of the things I would like to point out. 

The CHAIRMAN. Dr. Janetos, can you comment on the Science

Magazine article which claims that the two models used in the report, the Hadley Center and the Canadian, are not intended, or capable of predicting future impacts of climate change on a regional 

basis? 

Dr. JANETOS. Mr. Chairman, in the assessment we tried to be 

very careful to say what we have not done is try to predict exactly 

what the future will be like. Each of these models, each of these 

general circulation models was selected after a careful review of 

the criteria that we set a priori in order to understand the potential consequences. 

They had to have saved the right data, they had to have used 

an emissions scenario that was already well understood, and they 

had to be documented in the scientific review literature. 

What we have tried to do is essentially ask the question, what 

if the models are correct? Since we cannot distinguish between 

them on scientific bases, we need to be able to understand the implications of the different plausible futures that they hold for the 

U.S. 

The CHAIRMAN. Thank you. We will be submitting written questions that we hope you will be able to respond to. I apologize for 

the short-circuiting of this hearing. We will be asking the second 

panel to come back. We thank you for taking your time to come before the Committee. 

31

You have added a lot to this very important discussion, and I 

want everyone to be very aware that we will continue to pursue 

this with further hearings. I think that it is an issue that is extremely important for us to seriously consider, and I thank you for 

being here. I thank you for your continued efforts, and I hope I 

have the opportunity to personally visit with all the members of 

the panel as we explore this very complex and difficult situation. 

I thank you. 

Unfortunately, this hearing is adjourned. 

[Whereupon, at 10:10 a.m., the Committee adjourned.] 

(33)

A P P E N D I X

RESPONSE TO WRITTEN QUESTIONS SUBMITTED BY HON. JOHN MCCAIN

TO THOMAS R. KARL

Question 1. Can you explain the process used in the report to address the differences between the results of the two computer models and how this process is 

used to identify new research areas? 

Answer. A lexicon was developed to communicate scientific uncertainty related to 

the scenarios from the two climate models used in the National Assessment as well 

as other models, data, information, and state of knowledge. This lexicon conveyed 

areas of uncertainty by linking words with probabilities. For example, if the National Assessment Synthesis Team (NAST) assessed the about even odds for an 

event the word ‘possible’ was used. On the other hand, if the NAST was fairly certain about an event, then words like ‘‘very likely’’ or ‘‘very probable’’ were used to 

indicate that there was more than 90% chance of occurrence. Where both models 

agreed, projections were seen as more certain. In cases where model results differed, 

both possible future scenarios were examined and results were characterized as less 

certain. Model results were not merged. 

Whenever the NAST encountered instances where there was considerable uncertainty about the outcome these areas were then identified in a ‘Research Needs’ section of the report. In our Research Needs section we recommend a number of measures that are required to improve our confidence in modeling future climates.

Question 2. If the report explicitly does not ‘‘merge’’ the results of models that disagree, can this assessment be considered a fair analysis of climate change? Furthermore, when the two models diverged, where these results downplayed in the report 

versus when they concurred? 

Answer. In response to the first question, it is difficult to understand why the assessment would not be considered fair if the two primary models were not merged. 

As indicated above, the NAST did not merge the scenarios from the models, but 

rather the NAST reflected the uncertainty related to several different possible outcomes and expressed this lack of confidence through use of the lexicon. 

In response to the second question, the answer is no. Again, the NAST painstakingly used the lexicon to express its confidence in any projected changes for the 21st 

Century. Projected scenarios from all relevant models were discussed. This included 

both of the two primary models as well as the secondary models used in the Assessment.

Question 3. Dr. Schmitt has raised several issues concerning the impact of the 

oceans on the climate modeling results. How sensitive are the climate change impacts on the U.S. to changes within the ocean water temperatures? 

Answer. Dr. Schmitt’s remarks refers to improving climate forecasts from climate 

models that are dependent upon initial conditions. These deterministic climate 

model forecasts require information about the current state of the oceans. Clearly, 

it is very important to have comprehensive high-quality real-time ocean observations available to properly initialize these models. 

The Global Climate Models used in the National Assessment do not require realtime initial conditions. They are self-contained models and generate their own ocean 

climate. Changes in ocean temperatures can have a large impact on the climate of 

the U.S. An obvious example relates to the changes of ocean temperatures in the 

tropical Pacific related to the El Nin ̃ o southern oscillation and its effect on the temperature and precipitation in the U.S. Another example relates to hurricane formation. Water temperatures significantly less than 80 degrees Fahrenheit do not provide enough energy to the atmosphere to spawn powerful hurricanes. And as a result, hurricane formation is highly seasonal dependent.

Question 4. In the past few years, the U.S. experienced some distinctive weather 

patterns, namely El Nin ̃ o and la nin ̃ a. Can you discuss how these and other warm 

ocean water related weather patterns factors into your modeling efforts? 

34

Answer. First, it is important to understand that El Nin ̃ o and la nin ̃ a are the opposite phases of an oscillation that is atmospheric and oceanic based. As such, la 

nin ̃ a reflects cold ocean waters in the tropical Pacific while El Nin ̃ o reflects the opposite conditions, warm waters. Present-day Global Circulation Models are only now 

beginning to show success in simulating important ocean-atmosphere oscillations 

such as the El Nin ̃ o/Southern Oscillation. Neither of the models used in the National Assessment has a fully satisfactory representation of the El Nin ̃ o/la nin ̃ a oscillation, and it is likely that this has lead to some of the differences between model 

projections. The Global Climate Model that has been most successful in reproducing 

the El Nin ̃ o/la nin ̃ a events, primarily because of its higher resolution, is the Max 

Planck Model from Germany. Unfortunately, based on the NAST’s selection criteria, 

we could not use this model as a primary model, but the NAST was able to point 

out that this model projects a major increase in the intensity of both El Nin ̃ o and 

la nin ̃ a events as the globe warms. This could be very important, and in our Research Needs section of the National Assessment the NAST points out the importance of more research related to climate model inter-comparisons, representation 

of important ocean processes, and analysis of possible influence of climate change 

on existing patterns of climate variability.

Question 5. Do you anticipate that any of the ongoing university regional studies 

will contradict the findings of the current draft report? 

Answer. I do not anticipate that the any of the ongoing studies will contradict the 

current National Assessment Draft Report, but I would be surprised if they did not 

add additional insight into important issues and uncertainties. In assessing such a 

broad range of science, economics, and sociology, it was very clear to us that new 

understanding and insights were occurring continuously. Most often however, these 

insights made incremental additions to our understanding. A good example of this 

are the incremental advances in our understanding about global change as reflected 

in the series of Inter-governmental Panel on Climate Change Assessments completed during the 1990s. It is rare in science, that a discovery or theory completely 

displaces the old paradigm. We acknowledge that such things can occur however, 

such as the discovery of the ‘‘Ozone Hole’’ or Einstein’s Theory of Relativity. 

RESPONSE TO WRITTEN QUESTIONS SUBMITTED BY HON. JOHN MCCAIN TO

DR. ANTHONY C. JANETOS

Question 1. Some critics of this report charge that the Administration has ignored 

scientific and analytical procedures, and instead produced an advocacy-driven document. Given that most scientific studies are not open to the public, do you believe 

that ‘‘value’’ was added to the process by involving the public in this manner? 

Answer. The public has been involved in two ways throughout the assessment 

process. First, during the workshop phase of the process, in which more than twenty 

workshops were held around the country, broad public participation was sought. 

The role of the workshop participants was primarily to identify environmental 

issues of concern to people in the different regions of the U.S. This input was then 

used to help decide which issues of importance within each region would be followed 

up in scientific studies. 

The second way in which the public was involved was opening the Synthesis reports up to a public comment period, at the specific request of the Congress. We 

received many comments from people who otherwise might not have had the opportunity to read such a report at this stage in its development. Some of these comments have been quite insightful and helped us improve the document as a method 

of communication with a broad readership. 

It is correct that most national scientific processes have not been so open to soliciting input from the public. I argue that our process has been enhanced by the public participation that we received, without resulting in an advocacy-driven document. We have focused on issues that people perceived to be important to them, and 

not just on issues of interest to the scientific community. At the same time, we were 

able to bring up-to-date scientific knowledge and methods to bear on the issues that 

had been identified. Objective scientific and analytical procedures and methods have 

been used throughout. Our objectivity has been ensured by extensive peer review.

Would you also discuss the level of participation from the private sector? 

Answer. The private sector has been involved in several different ways. Our oversight panel is broadly representative of several different sectors, including academia, the for-profit private sector, and non-governmental organizations (NGO’s). 

The National Assessment Synthesis Team and other contributors to the national reports include individuals from all these sectors as well, plus experts from governVerDate Apr 24 2002 08:33 Sep 05, 2003 Jkt 083037 PO 00000 Frm 00038 Fmt 6601 Sfmt 6621 S:\WPSHR\GPO\DOCS\83037.TXT SCOM2 PsN: JACKF
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ment research laboratories. Many individuals in the private sector have reviewed 

all or part of the reports, and have offered their comments to us. Finally, many of 

the regional workshops included participants from the private sector, who were important contributors to the process of identifying issues for scientific analysis.

Question 2. Can you describe the peer review process that the assessment team incorporated into its findings? 

Answer. The peer review process had several steps. First was a round of technical 

peer review on the initial drafts of the national reports, which began in November 

of 1999, and continued into January of this year. We received more than 300 comments from individuals who identified themselves as technical experts in the many 

different aspects of the report. This technical peer review included experts in the 

government agencies, as well as academia, the private sector, and NGO’s. The second step was submitting the entire report to a list of about 20 experts identified 

by our oversight panel, who were charged with evaluating the entire structure of 

the report, its responsiveness to its original intent, and the strength of the findings 

and conclusions. Throughout, we have had the benefit of comments from our oversight panel. 

The National Assessment Synthesis Team has considered every written comment 

that it has received. We have responded to comments in writing, documenting either 

how the comment has been taken into account, or why we have decided not to do 

so. These responses to comments have also been shared with our oversight panel.

Question 3. How did your ‘‘bottom up’’ approach to the assessment report impact the 

findings or scope of your work? 

Answer. I believe that the approach of identifying issues through involvement of 

the public in the series of workshops did affect the scope of the work. Specifically, 

it enabled us to focus on the issues viewed as most important by the participants 

of the workshops. However, the analysis of those issues was done by experts, so that 

the actual findings themselves are the result of objective analysis.

Question 4. Did the oversight panel for the National Assessment Synthesis Team 

offer any cautious or contradictory statements throughout the reporting process? 

Answer. The oversight panel has been cautious throughout, and has been especially helpful to us in ensuring that we have described accurately the scientific basis 

for our findings, and been open about the degree of uncertainty that remains. They 

have not provided contradictory statements. 

RESPONSE TO WRITTEN QUESTIONS SUBMITTED BY HON. JOHN MCCAIN

TO DR. RAYMOND W. SCHMITT

Question 1. Your written statement mentions that the ocean is the long term memory of the climate system. Would you discuss what methods are available to retrieve 

that long-term memory? 

Answer. Most of the heat energy reaching Earth is absorbed into the upper ocean 

at low to middle latitudes. A significant fraction of this is used to heat and moisten 

the atmosphere on a daily basis, causing the winds and rain we experience as 

weather. But over the course of the seasons, large amounts of heat are stored within 

the ocean during spring and summer for release in the winter. This is the basic 

moderating influence of the oceans on climate; the vast heat capacity of the oceans 

prevents the winter from becoming too cold, and the summer from becoming too hot, 

especially in areas near the coast. But we have also found that ocean currents are 

capable of moving tremendous quantities of heat around the planet. This has an essential role in the climate system, fully half of the transport of heat from equator 

to pole is accomplished by the slow-moving, high heat-capacity ocean, with the other 

half of the heat transport carried by the fast-moving, low heat-capacity atmosphere. 

The atmosphere cycles its water vapor and heat within two weeks, so it has only 

a short-term memory of past conditions. However, the ocean’s heat-content is so 

large its memory time is decades to centuries, when the deep ocean is considered. 

The way to retrieve and interpret the long term climate memory of the oceans 

is to measure the temperature at depth. Satellites provide an estimate of the temperature of the ocean in a thin surface layer but tell us nothing about the deepreaching temperature signals necessary to help predict the climate a season or even 

a decade ahead. New technology of profiling floats (the ARGO program), new 

profiling moorings that measure temperature and salinity and maintenance of traditional ship-based observations will all help to acquire data on the deep temperature 

and salinity of the ocean. We will never decipher the mysteries of the climate system without measuring the dominant portion of its heat content that resides in the 

ocean.

36

Question 2. Would you briefly discuss the importance of ocean salinity (or salt content) to climate studies? 

Answer. Salinity variations have nearly as much influence on seawater density 

as temperature changes. This means that in the high latitude ocean salinity plays 

a very important role in determining whether the surface waters will be dense 

enough to sink and become deep water. Salinity can be decreased there by rain fall, 

river runoff and ice melt. If deep water ceases to form then the ‘‘thermohaline’’ circulation is disrupted and the warming influence of the North Atlantic on American 

and European weather is much reduced. Increased rainfall in high latitudes and 

subsequent collapse of the thermohaline circulation is a prediction of global warming models, with dramatic consequences for climate. However, the ocean models and 

measurements are presently inadequate to say whether thermohaline collapse is 

probable or even possible with global warming. In the tropics, high rainfall rates 

can cause low salinity water to collect at the ocean surface and modify the ocean’s 

transfer of solar heat to the atmosphere. Salinity variations in the ocean reflect the 

workings of the greater part of the global water cycle; a mere 1% of the rainfall on 

the Atlantic ocean would double the discharge of the Mississippi River. Yet salinity 

is a very poorly monitored variable; for many areas of the ocean, there has never 

been a salinity measurement. Thus, it is very important that we begin to make 

much greater use of new technology such as ARGO floats, moored and drifting 

buoys and ships to better define the patterns of salinity variation in the ocean. Only 

then will we achieve an adequate understanding of the global water cycle and its 

variations which are so important to society.

Question 3. You mentioned that because of computer limitations, many models must 

treat the ocean as a very viscous fluid, more like lava or concrete than water. What 

are the implications of this assumption? 

Answer. The models that are run for climate predictions cannot resolve or represent the smaller scales of variability in the ocean. This means that the many eddies and fronts we find in the real ocean (100 km in size and smaller) are not in 

the models. This introduces a number of defects in the models even for the large 

scales which are well resolved. For instance, some currents are driven by eddies, 

and without eddies such currents are not found in the models. Also, the ocean’s interior mixing processes are known to be caused by internal waves, yet there are no 

internal waves in the models. Mixing controls the patterns of the deep currents, 

which are notoriously wrong in the models. The problem gets worse for climate projections of decades or centuries, with many ocean phenomena missing or seriously 

misrepresented. Without an accurate portrayal of ocean dynamics, prediction of future climate states is fundamentally impossible.

Question 4. Your written testimony states that it is unlikely that we will have the 

necessary computer power over the next 160 years, even with an increased order 

of magnitude every 6 years, to simulate the smallest ocean mixing processes. What 

are our alternatives to gain a better understanding of these processes? 

Answer. Study the real ocean. We can develop a better understanding only 

through dedicated ‘‘process’’ studies focussed on these different phenomena. This allows the development of ‘‘parameterizations’’ of the small scale processes that can 

be used in the numerical models. The United States had a significant research effort 

on small-scale ocean processes during the cold war through support of the Office of 

Naval Research, but funds from that source are now much diminished. There is a 

great need for a revitalization of such work in order to bring the ocean climate models toward some semblance of reality. 

RESPONSE TO WRITTEN QUESTIONS SUBMITTED BY HON. JOHN MCCAIN

TO DR. S. FRED SINGER

Question 1. The report states that by using the two selected computer models, a 

plausible range of future actions are captured, with one model being near the lower 

end and the other near the upper end of projected temperature changes over the 

U.S. Do you agree with this statement? 

Answer. The National Assessment Report chose two climate models (out of perhaps two dozen) to provide scenarios for the 21st century. The selection criteria are 

not readily apparent. One model came from the Canadian Climate Center; it predicts extreme temperature rises over the U.S. (of 11°F by 2100). The other model 

chosen was produced by the Hadley Center in Britain; it predicts less extreme temperatures. 

The main point, however, is that BOTH models are already too high and therefore 

proven wrong by the temperatures observed in recent years. As shown in my testiVerDate Apr 24 2002 08:33 Sep 05, 2003 Jkt 083037 PO 00000 Frm 00040 Fmt 6601 Sfmt 6621 S:\WPSHR\GPO\DOCS\83037.TXT SCOM2 PsN: JACKF
37

* The information referred to was not available at the time this hearing went to press. 

mony, there has been no appreciable warming over the U.S. since about 1935, according to the analysis by Dr. James Hansen of NASA–GISS. Notwithstanding the 

oral response by Tom Karl, virtually the same is true for the analysis published by 

NOAA–NCDC. 

To verify this, it is only necessary to view the disparity between the observed temperatures (see my written testimony) and the calculated temperatures (see written 

testimony of Karl/Melillo/Janetos).

Question 2. What are your thoughts as to why regional forecasts from the climate 

models disagree so strongly in some areas and not as much in others? 

Answer. At the present state-of-the-art of climate models, regional forecasts are 

even worse than those for global averages. No reliance whatever should be placed 

on them. The strong disagreements between the model predictions themselves provide adequate confirmation for my statement.

Question 3. Your written statement mentions that a careful analysis shows that the 

warming of the early 1990’s actually slows ongoing sea level rise. Can you explain 

this finding? 

Answer. Sea levels have been rising for about 15,000 years, since the peak of the 

last ice age. The total rise has been about 400 feet. Sea levels are continuing to rise 

at a rate of about 7 inches per century, and will continue at about that rate for several millennia more as slow melting continues in the Antarctic. 

As global temperatures fluctuate (no matter whether from natural causes or possible human causes), the ongoing sea level rise may be expected to show slight modulations; it may slow down for some decades or it may accelerate. It all depends on 

whether a warming of the oceans produces a greater or lesser effect than an accumulation of ice in the Antarctic from increased ocean evaporation and subsequent 

precipitation. (These two effects on sea level oppose and nearly cancel each other.) 

When we investigated what happened during the major warming between 1920 

and 1940, we found empirically that the rise in sea level slowed down. We therefore 

expect that any future warming, unless extreme and sustained over many centuries, 

will likewise reduce the rate of sea level rise rather than accelerate it. The existing 

fears about rising seas from greenhouse warming have no scientific foundation 

whatsoever. They are based on hype rather than observed facts.

Question 4. Do you accept the claim that the 20th century was the warmest of the 

past 1000 years? 

Answer. The claim that the present century is the warmest of the past 1000 years 

relies on the ‘‘hockey-stick’’ temperature graph (Mann, Bradley, and Hughes, Geophysical Research Letters 1999). It is derived from various proxy data rather than 

thermometer records; yet it has been widely cited. It forms the cornerstone of the 

claimed ‘‘discernible human influence’’ in the Summary for Policymakers of the 

IPCC-Third Assessment Report. 

The graph is actually a composite of two records: (i) temperatures from ‘‘proxy’’

data (tree rings, etc.) going back to 1000AD; and (ii) a superimposed global instrumental (thermometer) record of the past century. 

Close examination reveals that the proxy record stops in 1980 and therefore does 

not independently support the post-1980 temperature increase suggested by the 

thermometer data. Thus there is no evidence for a substantial warming since 1980 

(or even since 1940). There is no evidence for the claim that the present century 

is the warmest of the past 1000 years. And there is no evidence to back the claim 

of a ‘‘discernible human influence’’ on global climate. 

PREPARED STATEMENT OF HON. LARRY E. CRAIG, U.S. SENATOR FROM IDAHO

Mr. Chairman, thank you for inviting me to testify at this very important hearing. 

On June 16, 2000, I spoke on the Senate Floor about the Administration’s recently 

released draft National Assessment Synthesis Report. I ask that a copy of that 

Statement be included in the record of this hearing.* 

Mr. Chairman, the potential of global climate change is one of the most important 

environmental issues of this new century. The stakes are high. Worst-case scenarios 

involving rising temperatures and sea levels scare many people. On the other hand, 

premature government action to cut back energy use to levels lower than those in 

the growth-oriented nineties could cool the economy faster than it cools the climate. 

What is required at this time, Mr. Chairman, is steady and thoughtful leadership. 

Responsible government includes environmental stewardship. However, the ultimate 

38

obligation of government is to protect freedom. By freedom I mean the opportunity 

to achieve one’s true potential as an individual, a community, or a nation: the freedom to grow! 

Freedom spawns discovery and innovation. Discovery and innovation solve problems and create opportunities. This is the true spirit of America. 

Mr. Chairman, today you will have the co-chairs of the National Assessment before you. These are accomplished men with impressive scientific backgrounds. The 

Committee will have the opportunity to question them on a document that I believe 

is long on fear and short on conclusive science. 

Let me lay-out some of the reasons why I am so concerned about this document. 

The National Assessment process was authorized under the Global Change Research Act of 1990 but did not officially begin until January, 1998—one month after 

the Kyoto Protocol. The final report was expected in January, 2000, but was delayed. 

Last year, in the Fiscal Year 2000 appropriations, Congress directed that all research used in the National Assessment must be subjected to peer review and made 

available to the public prior to use in the Assessment, and the Assessment must 

be made available to the public through the Federal Register for a 60 day public 

comment period. This was not challenged by the Administration. 

The Administration released a ‘‘draft’’ summary report on June 12th of this year 

by posting it on a website and publishing a notice in the Federal Register that it 

was available for comment until August 11th. This action is clearly at odds with 

Congressional intent. The underlying regional (geographic) and sector (health, agriculture, forests, water, coastal) work that was to have served as the basis for the 

summary report has not been completed or made available for review. 

In a June 30th letter to Congressman James Sensenbrenner, Chairman of the 

House Committee on Science, Neal Lane, who testified before this Committee on 

May 17th Mr. Chairman, stretched credibility in defending this action. Although 

taxpayer funds were provided to support the work, he claimed the underlying reports were not ‘‘federal’’ reports and therefore not covered by the earlier Congressional guidance. The underlying reports are to be completed over the next year or 

so and published by the respective teams working on them. 

Mr. Chairman, a question that begs an answer is: Why the rush to release the 

National Assessment? The premature release of this document allows for more polarizing advocacy. Although supposedly a ‘‘draft’’ report published for technical review and comment, it was trumpeted by President Clinton on the day of its release 

and served as a basis for repeating tired claims: 

‘‘It suggests that changes in climate could mean more extreme weather, more 

floods, more droughts, disrupted water supplies, loss of species, dangerously rising 

sea levels.’’

It’s easy to miss (or ignore) the qualifications to these predictions and simply report that the Assessment forecasts dire changes in climate in the future. For example, a page one story in The New York Times on June 12th carried the headline: 

‘‘Report Forecasts Warming’s Effects—Significant Climate Changes Predicted for the 

Country.’’

In Texas, a July 4th story by the environmental reporter at the Dallas Morning 

News reported on action by five environmental groups asking Governor Bush—‘‘to 

launch a Texas assault on global warming, which scientists say could heat up North 

Texas in the next century.’’ The story went on to discuss the draft National Assessment including the comment—‘‘Two computer simulations of the future of Texas climate show sharp rises in the July heat index, with the worst impact in North 

Texas.’’

Not everyone has been misled. The Wall Street Journal published an article entitled: ‘‘U.S. Study on Global Warming May Overplay Dire Side’’ on May 26th, in anticipation of the impending release. A similar story ran in The Detroit News on May 

28th. Numerous Op-eds and Letters to the Editor have also run. 

However, Mr. Chairman, the early release of this document raises more intriguing 

political questions than helpful probative scientific ones. For example, it puts the 

Assessment on a timetable for inclusion in the UN’s Intergovernmental Panel on 

Climate Change’s ‘‘Third Assessment Report’’ on climate change which is due to be 

finalized next year. In fact, Mr. Chairman, I have been informed by staff that drafts 

are already circulating for comment and these drafts include references to the U.S. 

National Assessment. 

It is becoming clear that the June 12th release of the Assessment is serving as 

support for campaign claims by Al Gore to support his views on climate and energy 

use. Indeed, his release on environment and energy policy occurred just two weeks 

later on June 26th. 

39

Mr. Chairman, the Administration could have avoided seeding these concerns if 

it had followed the common sense approach requested by Congress and taken the 

time to get it right:

First, complete the underlying regional and sector work, peer review the science 

used as its basis, and make the results available for public comment; 

Second, write the synthesis overview report based on this work, not independently, peer review the results and make a complete draft easily available for all interested citizens to review with enough time to gather complete comments and expose them to the public. 

In addition, Mr. Chairman, the independent National Research Council should 

have a strong role in the drafting process, not just White House allies as implied 

in some critiques. 

Lastly, but importantly, one must question the use of foreign computer models in 

this study. Was this in our best interest? The National Assessment used a Canadian 

and a British Large Scale General Circulation Model (GCM’s) to make climate 

change predictions at a regional level. According to a June 23rd Science Magazine

article entitled ‘‘Dueling Models: Future U.S. Climate Uncertain,’’ there is a clear 

consensus of opinion in the scientific community that these models are not intended, 

or capable of, predicting future impacts of climate change on a regional basis. Even 

the EPA web site makes this point. 

The mere use of the foreign computer models in the National Assessment once 

again, begs an answer to an obvious question: What needs to be done to improve 

U.S. modeling capability? Other questions that need answers are: How well has the 

current Administration been spending our money in the climate arena? Do we have 

our scientific priorities in order? 

These, along with many other questions, I hope will be asked of those testifying 

before you and the Committee this morning. We must pursue a more consensus 

building approach to the climate change issue. Senator Frank Murkowski and I 

have introduced legislation that we believe provides a framework for national consensus—making continued stalemate on this issue unnecessary and intolerable. We 

have the vehicle to move forward. We should do so expeditiously, and with the constructive support of the Administration. 

Thank you, Mr. Chairman. 

PREPARED STATEMENT OF HON. FRANK H. MURKOWSKI, U.S. SENATOR FROM ALASKA

I want to thank Chairman McCain and the members of the Committee for holding 

this hearing today to review the recent National Assessment Report on climate 

change and its impacts on the United States. 

The report estimates effects of climate change on various regions of the country, 

and various sectors of our economy, such as agriculture and water resources. At the 

heart of this report are ‘‘potential scenarios’’ of climate change over the next 100 

years predicted by two climate models—one from Canada, and the other from the 

United Kingdom. These two climate models were ‘‘state of the art’’ three years ago 

when work began on this report, but it’s important to note that significant advances 

in our ability to model climate on regional scales have been made since then. 

These ‘‘scenarios’’ of climate change were then used to drive other models for vegetation, river flow, and agriculture—each of these models have their own set of assumptions and limitations reflecting incomplete understanding of the Earth system 

and its component parts. 

The end result of the three-year study is a 600 page report that paints a rather 

grim picture of 21st Century climate. Now the environmentalists and others in favor 

of the Kyoto Protocol are shouting from the rooftops—saying that these ‘‘potential 

scenarios’’ mean that we should go forward with drastic and costly measures to limit 

greenhouse gases. 

As the Committee considers the National Assessment Report today, I encourage 

you to look beyond the rhetoric to the science that underlies this assessment—we 

are only just now beginning to conduct the kind of scientific research that will allow 

us to determine impacts of climate change on the regional and local scales that are 

most relevant to our constituents. 

For example, a reasonable test of a climate model is whether or not it accurately 

simulates today’s climate—the National Assessment’s own science web site displays 

a chart that compares rain and snowfall predicted by the two climate models to actual measured precipitation (see attached Figure). The areas in blue and purple reflect areas where the model predicts more than TWICE as much rainfall as observed—if you live in an area with 10 inches of rain, the model would predict that 

you get 20 or more. Similarly, the areas in red reflect areas where the model preVerDate Apr 24 2002 08:33 Sep 05, 2003 Jkt 083037 PO 00000 Frm 00043 Fmt 6601 Sfmt 6621 S:\WPSHR\GPO\DOCS\83037.TXT SCOM2 PsN: JACKF
40

dicts less than HALF as much rainfall as observed—if you actually get 10 inches 

of rain, the model would predict that you get 5 or less.

41


718murk1.eps
42

Now, we know that the amount of rain and snow falling within a river basin determines river flow—which determines:

• the amount of water for irrigation of crops

• the health of fish species

• the generation of hydroelectric power

• and the water available for human use

So depending on what the climate models say, you can imagine very different impacts—and if the models are off by 50 or 100% in either direction, so too could be 

the estimates of impacts from climate change on these sensitive areas of the environment and our economy. This is just one example of the need for continued scientific research to understand the entire Earth system and how it responds to 

changes in atmospheric trace gas concentrations. 

Nonetheless, the National Assessment has been a very useful exercise: it shows 

the difficulty of estimating regional impacts of climate change; it highlights the need 

for additional scientific research (namely improved climate models and observing 

systems); and it reminds us of the potential risk of climate change—a risk that we 

should responsibly address through the construction of a national energy strategy 

that includes consideration of climate change and its potential risks. 

The Committee on Energy and Natural Resources, which I chair, has held a number of hearings on climate change and its economic consequences for the United 

States—and the findings are not encouraging. If we heed the environmentalists’ call 

and ratify the Kyoto Protocol, American consumers would see gasoline prices above 

$2.50 per gallon and watch their electricity bills increase by over 85%, according to 

the Energy Information Administration. These projections have withstood scrutiny 

and have been confirmed by numerous other studies of Kyoto and its economic impacts. 

Furthermore, the Kyoto Protocol will not lead to stabilization of greenhouse gas 

concentrations in the atmosphere—the principal goal of the Framework Convention 

on Climate Change signed by the U.S. in 1992. Without developing country participation in the Protocol, greenhouse gas emissions would continue to rise as a result 

of industrialization and increased energy needs of China and India—nearly onethird of the world’s population. No matter what kinds of cuts in emissions we make, 

Kyoto will not result in any meaningful difference in the climate. 

As the Senate stated when it passed S. Res. 98, the ‘‘Byrd-Hagel Resolution’’ regarding climate change, a climate treaty must include meaningful developing country participation and must not come at economic cost to the United States. Neither 

of these conditions have been met in the current Kyoto Protocol, and it is clear to 

me that we need an alternative approach to addressing the risk of climate change—

one that recognizes the global, long-term nature of the problem. 

To this end, I have sponsored, with Chairman McCain and 19 other Senators, the 

Energy and Climate Policy Act (S. 882) which provides a technology-based alternative to the Kyoto Protocol. Our bill:

• Creates a new $2 billion effort over the next ten years to cost share technology 

development with the private sector;

• Creates an Office of Climate Change within the Department of Energy to coordinate research and development activities across a wide range of energy 

technologies; and

• Promotes voluntary reductions by improving the government’s system of tracking voluntary emissions reductions.

Senator Craig has also introduced a bill (S. 1776) that I have cosponsored which 

complements S. 882—it addresses some issues such as strengthening coordination 

between elements of the U.S. Global Change Research Program. We anticipate including elements of Senator Craig’s bill in an amended version of S. 882 when we 

consider it later in the year. I welcome interest from members of the Committee if 

they wish to review our legislation and offer comments or amendments. 

In summary, I believe that we should take prudent steps to address the possible 

risks of climate change, but we should recognize the global, long-term nature of the 

problem and respond accordingly. A balanced portfolio of energy options, including 

expanded use of natural gas and continued reliance on emissions-free nuclear and 

hydro power, would produce fewer greenhouse gases than the Administration’s current energy plan. We should expand existing emissions-free technology, including 

nuclear, hydropower, solar, wind and biomass, but we should also promote new technology to trap and store greenhouse gas emissions from the atmosphere and encourVerDate Apr 24 2002 08:33 Sep 05, 2003 Jkt 083037 PO 00000 Frm 00046 Fmt 6601 Sfmt 6621 S:\WPSHR\GPO\DOCS\83037.TXT SCOM2 PsN: JACKF
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age voluntary actions to reduce greenhouse gases and use energy more efficiently. 

We should also invest in a new generation of energy technologies that can be deployed in developing countries, preventing greenhouse gas emissions before they 

occur. The risk of human-induced climate change is a risk we should responsibly address, and a balanced, technology-driven energy strategy offers us the means to do 

so. As we consider our future national energy strategy (which drives our greenhouse 

gas emissions), we now have an excellent opportunity to address our environmental 

concerns at the same time that we address our growing dependence on foreign oil. 

I thank Chairman McCain and the members of this Committee for their interest 

in these issues, and look forward to working with you on establishing a balanced 

energy portfolio that makes good sense for our economy, our environment, and our 

national security. 

PREPARED STATEMENT OF THE ANNAPOLIS CENTER

Global Climate Modeling:

Helping to Understand Strengths and Weaknesses 

Introduction 

The public’s and decision-makers’ understanding of the strengths and weaknesses 

of computer modeling of global climate is essential to the formulation of long-term 

policies related to global climate change. In the hope of facilitating better understanding of the status of climate modeling, the Annapolis Center gathered a diverse 

group of experts for discussion of the status of climate modeling and to prepare this 

report. 

The majority of the group’s views on this general subject were as follows:

• There are a number of ‘‘greenhouse’’ gases in the earth’s atmosphere, including 

water, in the form of vapor, CO2, and methane. (Water vapor is a much stronger 

contributor to the natural [non-anthropogenic] greenhouse effect than CO2.)

• Atmospheric carbon dioxide (CO2) has been increasing for more than 100 years, 

almost certainly in large part because of human activity.

• There are growing indications that global near-surface temperatures have increased over the past century by about 1°F (0.6°C). Temperatures in the lower 

five miles of the atmosphere, the lower-to-mid troposphere, have increased only 

slightly, if at all, in the past several decades of instrumental monitoring.

• Natural increases in atmospheric CO2 in the Earth’s past have been well documented, however, the cause-and-effect relationships with past climate change 

are not clear.

• The rate of increase of CO2 in the atmosphere in the past century is greater 

than any previously recorded historic rate.

• How much of the observed warming is caused by human activities and by natural climate variations is uncertain. 

Climate Modeling and Simulation 

How can we understand the earth’s climate system and the possible consequences 

of increased concentrations of greenhouse-gases in the atmosphere? We can do some 

things in the laboratory, but because the earth’s climate system is so large and incredibly complex, we can recreate only small pieces of it in the lab for extensive 

study. So scientists develop computer models based on the governing physical principles as expressed by mathematical equations that describe many of the processes 

that may affect climate. Such models act as simulation laboratories in which experiments can be performed that test various assumptions and combinations of events. 

These experiments not only can expand our knowledge, they can also develop insights into possible climate futures. 

Although there are a variety of increasingly complex climate models, only the 

‘‘general circulation model’’ (GCM, sometimes also referred to as a global climate 

model) determines the horizontal (geographical) and vertical (atmospheric and oceanic) distributions of a group of climatic quantities, including (1) temperature, wind, 

water vapor, clouds and precipitation in the atmosphere; (2) soil moisture, soil temperature and evaporation on the land; and (3) temperature, currents, salinity and 

sea ice in the ocean. The related equations are so complex, however, that they can 

only be solved for specific geographical and vertical locations, and only over specific 

time intervals. For example, a typical GCM subdivides the atmosphere into thouVerDate Apr 24 2002 08:33 Sep 05, 2003 Jkt 083037 PO 00000 Frm 00047 Fmt 6601 Sfmt 6621 S:\WPSHR\GPO\DOCS\83037.TXT SCOM2 PsN: JACKF
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sands of three-dimensional volumes, each having linear dimensions of about 250 

miles in the north-south and east-west directions, and a mile in the vertical direction. The task of making these boxes smaller is severely limited by the speed of even 

present-day supercomputers. For example, decreasing the horizontal size of a GCM 

from 250 to 25 miles would increase the required computer running time by a thousand fold—from about 2 weeks to more than 30 years of run-time to compute the 

resulting change in the equilibrium climate of the model! 

The Uses of Climate Models 

Until the advent of supercomputers, our attempts at climate modeling were rudimentary. That situation changed roughly 25 years ago. Much of the recent attention 

by the public and decision-makers on climate change has been due to measurements 

indicating that warming has been occurring near the Earth’s surface over the last 

century and to relatively recent projections from GCMs. 

Climate varies naturally over both short and long time scales, sometimes rather 

dramatically over a few years or decades. This rapid variability was experienced in 

Europe during the Little Ice Age of 1400–1850. To understand climate change, scientists must understand the detailed nature of the extremely complex climate system. While we have learned a great deal, there is still much we do not know. Climate models today can give us insights into what might happen under various assumed situations. 

Currently, there are about 30 GCMs being developed and/or used by research 

groups around the world. Many of these models are related, with the differences 

among the models lying in the natural processes they include and how they integrate and treat these processes within a specific model. 

As discussed above, computer models are necessary in the study of climate change 

because of the extraordinary complexity and number of the physical processes that 

are embodied in the climate system. Some of the factors that affect climate include:

• the concentrations of gases and aerosols;

• interactions between the atmosphere, the biosphere, and oceans;

• volcanic activity; and

• interactions of components within the atmosphere and ocean themselves.

The growth of computing capacity has allowed scientists to integrate complex climate-system processes into single computational frameworks. These frameworks can 

be used to develop an increasingly more comprehensive, but still incomplete, overall 

picture of the global climate system. 

The Roles of GCMs 

The general uses of GCMs are: 

First, the building and running of a model is a process by which theory and observations are mathematically evaluated, codified and integrated in a computer program. Models can thereby be used to identify needed refinements in theory and observation. Model building is a long process of back and forth comparisons between 

analytical description (‘‘theory’’) and field studies (‘‘observational data’’). These comparisons include end-to-end efforts to correlate observational findings with improvements in model representations. 

Second, climate models are used to identify and then assimilate observational 

measurements that are initially incomplete. These measurements can then be used 

to derive more consistent, spatially specific estimates of meteorological quantities. 

Such model-assimilated data have proven to be of great utility to the research community in better understanding the observed and potential variability of the climate 

system. 

Third, models can be used to focus observational activities. In regions where data 

are sparse, models can be used to define the frequency, coverage, and type of measurements that may shed the most light on the physics, chemistry and the composition of the atmosphere. 

Fourth, climate models have recently predicted a few climate anomalies up to a 

year in advance. These model predictions, which are increasing in accuracy, incorporate information on the current state of the oceans and atmosphere. Predictions 

of El Nin ̃ o and La Nin ̃ a events and climate anomaly patterns associated with these 

phenomena have proven reasonably accurate and there is potential for this type of 

model prediction to be extended out beyond a year. 

Fifth, climate models can be used to develop scenarios of possible future states 

of the climate system, given a specified set of assumptions (e.g., the future quantities of greenhouse gases, including ozone trends and aerosols). Such climate scenarios can then be used to develop projections of possible climate-related impacts 

45

on human and natural systems. Models currently show large-scale climatic response 

to increased greenhouse gas levels: for instance, (1) there may be some warming at 

the surface, warming of the troposphere, and some cooling in the stratosphere; (2) 

there may be greater warming at high latitudes than at low latitudes; and (3) there 

may be an increase in low level humidity over the oceans. Such fingerprints of 

human-induced climate change have been compared with the observed climate to 

help detect its changes and attribute its causes. 

From the GCM-based projections of climate change, analysts can begin to evaluate 

the potential impacts on market and non-market sectors of society. As these impact 

models become more sophisticated, increasingly better pictures of what might happen under different scenarios will develop. More research on impacts will help countries identify the seriousness of possible climate change and allow them to study the 

cost-benefits of various response options. 

In addition, models can be used to facilitate an understanding of the lag time between causes and effects associated with human as well as natural causes of climate 

change. It is essential to keep in mind that model projections depend on the sophistication of the model: the estimates in the model, the assumptions used by the 

model, and what in nature is not yet understood and therefore not covered in the 

model. This is why the climate research community generally places so much emphasis on verifying model results with actual data. By exploring sets of these model 

projections, the policy community can begin to discuss the effects that policies, 

aimed at reducing greenhouse gases, might have on climate, humans, and economies. 

Models & Decision-Making 

Existing GCMs can make ‘‘what if’’ projections of future global climate possibilities because they are the best available tools, even though they are currently limited 

in resolution and completeness. Regionally specific information is ultimately needed 

because, for example, while U.S. citizens have interest in what happens to the planet as a whole, they are especially interested in what happens to the U.S. and to 

their own neighborhood. Global climate projections from different models show a 

range of effects. The range of effects is largest for smaller regions. Partly, this is 

due to the natural local variability of climate and partly this is due to scientific uncertainties. 

Just as global climate models have advanced, so have global economic impact 

models for estimating costs and benefits. Integrated assessment models, which take 

into account chains of events (if ‘‘A’’ happens, then results ‘‘B’’ could occur, but if 

‘‘A’’ does not happen, then ‘‘C’’ will occur), are a tool to help understand long-term 

costs and benefits. 

Limitations of Models 

Having discussed the uses and strengths of GCMs, one should not assume that 

they do not have weaknesses—in fact, some scientists would state that the weaknesses are so great as to question their value in near-term decision-making. Some 

of the features of the GCMs are less robust than others, partly because there is disagreement between the models about predicted climate changes. Furthermore, even 

if the models agreed, it does not necessarily make them correct. 

Phenomenological Feedbacks 

Much of the uncertainty in current climate models is associated with 

‘‘feedbacks’’—how various phenomena interact with one another. Feedback mechanisms are clearly important. Climatologists agree that, without these feedbacks, a 

doubling of CO2 would give about a 1.8°F (1°C) rise in global-average temperature. 

Many phenomena have large impacts on others, some amplifying and some dampening effects. Some extremely important phenomena, the feedback consequences of 

which we do not fully understand, are the following:

• Clouds;

• Ice;

• Land surface processes;

• Ocean effects;

• Biological processes;

• Physical and chemical reactions in the atmosphere;

• Particulates;

• Solar cycle effects; and,

46

• Tropical convection and rainfall.

These phenomena are not yet adequately understood in isolation, let alone in combination with other factors. Thus, scientists must utilize approximations, estimates 

of aggregate regional effects, or ignore some phenomena all together for the time 

being. Other suspected feedback mechanisms are yet to be described or modeled. 

For example, the role of clouds and water vapor in climate models is not well understood; yet water vapor is the most significant greenhouse gas in the natural 

(unperturbed) atmosphere and dramatically affects cloud cover and the transfer of 

radiant energy to and from the Earth’s surface. 

Also, modeling the impact of clouds is difficult because of their complexity and 

compensatory effects on both weather and climate. Clouds can reflect incoming sunlight and therefore contribute to cooling, but they also absorb infrared radiation that 

would otherwise leave the earth, thereby contributing to warming. 

Parameters 

Models utilize observational data to adjust various model parameters to help 

make such parameters more realistic. ‘‘Tuned’’ models, however, cannot be validated 

by the data for which they were adjusted and must be validated by independent 

means. 

As previously mentioned, the equations related to the climate to be modeled are 

so complex that they can only be solved at specific geographical and vertical locations, and only over specific time intervals. The limit on horizontal size imposed by 

present-day supercomputers also limits the physical processes that can be explicitly 

included in a GCM. As discussed above, GCMs using today’s supercomputers explicitly include physical processes having horizontal sizes of approximately 250 miles 

and larger. Worse yet, the physical processes smaller than 250 miles cannot be ignored because their effects can significantly impact climate and climate change. 

Thus, climate modelers face the dilemma that their models cannot resolve the smallscale physical processes and they cannot ignore their effects. This is one, if not the 

major difficulty in modeling the Earth’s climate. The approach taken to overcome 

this problem is to determine the effects of the small-scale physical processes on the 

larger scales that can be included in a GCM using information on those larger scales 

and statistical relationships. This approach is called ‘‘parameterization.’’ The principal differences among GCMs lie in their approaches to parameterization, particularly in the case of cloud and precipitation processes. These parameterization differences have a significant influence on differences in climate sensitivity—the 

change in the equilibrium global-mean surface temperature resulting from a doubling of the CO2 concentration—between various GCMs. 

Testing Models 

One way that models are tested is to use them to reproduce past events and variations. The earth’s climate has been changing for millions of years but we do not 

have detailed data on those changes because humankind was not acquiring relevant 

data until relatively recently. As such, we cannot accurately truth test climate models over past periods of time beyond much more than a hundred years. Thus, we 

are asking these models to assist us in decision-making in an environment of considerable scientific uncertainty. There is, however, significant effort underway to compare the general nature of model simulations of pre-historic time periods against 

data from proxies (e.g., tree-ring widths, borehole temperatures, and oxygen isotopes 

in sediments) of past climates. 

Human Resources 

Compared to intermediate and smaller modeling efforts, such as those aimed at 

understanding the behavior of a particular climate process over a single locality, insufficient U.S. and international resources for research and computer hardware are 

being devoted to high-resolution global climate modeling. 

Data 

Instrumental temperature measurements of varying quality exist for about 135 

years. Relatively crude but useful information before then has been obtained from 

proxy data such as the width of tree rings and the abundance of certain isotopes 

trapped in ice cores taken from the ice caps and glaciers and in sediment cores 

taken from the deep sea and lakes. 

Climate data are routinely collected for weather prediction. Much of this data 

gathering was not designed to detect subtle trends that occur on decadal or longer 

time scales. For climate modeling, we need more accurate and extensive data than 

even currently used in weather prediction. There is also a need for better organization and long-term archiving of climate data. 

47

Advancement of Models 

Model development has progressed considerably in the past decade. However, 

though there have been downward modifications in estimates of future climate 

change (e.g., through the inclusion in models of the effects of aerosol cooling), the 

limits of uncertainty in possible global-average warming for a future doubling of 

CO2 have not been narrowed; that uncertainty has been in the 2.7–8.1°F (1.5–4.5°C) 

range for the past 20 years for most GCMs. 

While the capacities and speed of supercomputers have progressed dramatically 

in recent years, climate models remain constrained by current computational capacity. In fact, the leading climate models are no longer in the United States because 

U.S. researchers do not have access to the more powerful Japanese computers that 

other nations (i.e., Canada, Japan, United Kingdom) are using. Current computer 

capabilities applied to climate modeling are modest compared to what is needed to 

run high-resolution simulations using GCMs. Current computer limitations require 

that we settle for grid sizes that are much larger than needed to model some important phenomena such as tropical convection and precipitation. 

The participants in the discussion agreed with the National Research Council’s 

Report ‘‘Capacity of U.S. Climate Modeling (1998)’’ statement of the Council’s ‘‘summary results’’, if not all the details of its Report. 

Conclusions 

There are significant uncertainties in predicting future climates as a consequence 

of (a) natural climate variability; (b) the potential for uncertain or unrecognized climatic forcing factors (e.g., explosive volcanism, new or unknown anthropogenic influences, etc.); and (c) inadequate understanding of the climate system. We must expect that new observations or results from studies of global climate processes may 

yield information that causes us to re-evaluate and improve the capability of climate 

models. Our estimates of the credibility of climate system models can be, of necessity, consistent only with known facts and only based on the ‘‘best’’ current knowledge. 

Projections vs. Predictions 

Thus, it was the consensus of the experts convened by the Annapolis Center that 

climate models may never be able to make greenhouse-warming PREDICTIONS 

with certainty because of the enormous number of variables involved and the uncertainty inherent in the future. On the other hand, models of greenhouse warming are 

essential in the learning process. Climate models can be used for making PROJECTIONS based on various assumptions that in turn may be useful in understanding 

the consequences of various human activities and policy alternatives. When such 

projections will represent possible real climate futures is difficult to judge because 

of the enormous scientific uncertainties involved. 

CLIMATE PROJECTIONS are ‘‘what-if’’ scenarios about what might happen 

under a set of ASSUMED conditions. Projections may change as more knowledge 

is acquired. 

When weather forecasters make predictions one day or a week in advance, they 

can verify their predictions soon thereafter. Climate projections for the next century 

cannot be verified so easily. 

Continued climate warming year after year is not likely to occur. Periods of apparent cooling, however, would not necessarily mean that the Earth was not slowly 

warming over the long term. Similarly, if we were to experience warming year after 

year, we should not assume that man-made climate change was the primary or only 

cause. 

Though Better Understood, We Still Have A Long Way To Go 

Global climate science has progressed significantly in recent years but our lack 

of knowledge is still great. A major vehicle for understanding the enormously complex global climate system has been computer modeling. Today’s GCMs have developed rapidly relative to earlier models and provide improved estimates of what may 

happen in the future. Many believe that such models are still in a relatively early 

stage of development. Nevertheless, GCMs are important research tools that can 

help to focus the research and measurements needed to better understand climate 

change. Climate modeling will be increasingly more valuable as models and our understanding of basic processes are improved. 

Models of climate changes are still evolving because we do not yet completely understand or model everything that can or will affect climate. Scientific uncertainty 

will always be a component of modeling climate change. Our challenge is to reduce 

this uncertainty. 

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Because of the Uncertainty, Care Must Be Used in Decision-Making 

Care must be taken when using the results of climate models for major public policy decisions because of the existing uncertainty, as well as our lack of knowledge 

about important physical and chemical reactions in the atmosphere and oceans. 

Adapt Via ‘‘Act-Learn-Act’’

Because man-made greenhouse gas emissions are likely to continue to increase in 

the future, the workshop participants endorse adaptive and affordable management 

strategies, such as ‘‘act-learn-act,’’ that are robust against what we do no yet know. 

We will surely be learning more about climate change over time. As we learn more, 

we must revisit greenhouse-related policies and adjust them accordingly. 

PREPARED STATEMENT OF DR. PETER B. RHINES, PROFESSOR,

UNIVERSITY OF WASHINGTON

Climate change takes on real force when it combines with human activity. It produces multiple and compounded changes of the physical environment, and of ecosystems. The U.S. feels these impacts from beyond national boundaries, from the 

global atmosphere and ocean. 

There are many points of contention: between modification of our environment 

and accommodation to it; between natural and human-induced climate change; within the scientific debate, between the need for prediction and the need for diagnosis. 

Improved observation and understanding of the current and past states of the environment (the atmosphere, ocean and land surface) may be just as important as attempts to predict its future. 

As Dr. Schmitt has earlier this morning described, the ocean plays a particularly 

interesting role in climate: it dominates the storage of heat and carbon and water; 

it also contains a significant fraction of global biological activity: photosynthesis and 

respiration. It is a well-spring of diversity, harbors newly discovered forms of life, 

and in the search for natural pharmaceuticals it is richer than the land. 

Large-scale oscillations of climate. El Nin ̃ o/Southern Oscillation (ENSO), centered 

in the tropics, is an ‘argument’ between ocean and atmosphere which radiates across 

N. America. With enormous impact on temperature, rainfall, storms, flooding, 

drought, there is some good news in an el nin ̃ o winter, and much bad news. 

In the far northern Atlantic Ocean, the paths followed by intense storms over the 

ocean have moved north since the early 1970s. These storms intensify as they suck 

heat from the ocean. This is a part of the so-called North Atlantic Oscillation (NAO), 

which can switch regimes from one month to the next, or from one 30 year period 

to the next: it has an element of unpredictability. It is intimately related to the jet 

stream and polar vortex, a ‘tall’ mode that reaches to the stratosphere. The NAO 

is one of several important patterns of oscillation of the atmosphere outside of the 

tropics (others include north-south ‘annular oscillation’ of the jet-stream system in 

the Southern Hemisphere, and a great wave round Antarctica that appears to be 

coupled between ocean and atmosphere). 

In addition to its many impacts on weather, drought and flooding, the NAO is involved in the great, deep overturning circulation of the ocean. The temperature and 

salinity of the oceans both condition its fluid density . . . its ability to sink. It is 

at high latitude that the ocean is chilled by the atmosphere, and in rare and small 

regions, water sinks to the abyss. This global system fulfills the need for heat to 

be transported from the warm latitudes to the cold, where it radiates to space. 

Nearly horizontal layering of the oceans, with dense waters sinking beneath buoyant surface waters, is the result of this ‘heat engine’ and it is of great consequence 

to the distribution of ocean life. Photosynthetic life needs sunlight and nutrients. By 

controlling the flow of nutrients from their rich store at depth, upward to the sunlit 

surface, life of the ocean is determined by its patterns of its up/down, north/south 

circulation. This ‘meridional overturning circulation’ provides a severe challenge to 

computer models, because of the small yet essential features and the complex shape 

of the solid Earth. While current computer models have many inaccuracies, they are 

increasingly being subjected to the acid test of focused, small scale seagoing observational programs. 

ENSO and NAO are examples of the possible expression of global warming in 

‘modes’ . . . that is patterns of ocean and atmosphere response with warm and cold, 

wet and dry. The Titantic sank in 1912, during a cold period that encouraged icebergs to reach southward into shipping lanes. There followed two major periods of 

global warming this century, the 1930s–40s and 1970s–90s, which in fact correlate 

with phases of the NAO. These modes are good tests of computer models of climate, 

and indeed are the subject of intense simulation work at present. 

49

Northern Asia and Canada experienced some of the most intense warming in the 

1990s, dominating the global average: we in the U.S. have not yet seen the full force 

of warming. The northern Atlantic actually has cooled for many years, as cold, Arctic air blew from Canada with increased vigor. Greenhouse warming is expected on 

average to be initially severe in the Arctic, and to increase the water vapor in the 

atmosphere. In N. America, increased precipitation and streamflow out into the 

ocean has developed. Together with the long feared, and now observed, thinning and 

meltback of the Arctic sea ice, these events are portentous. 

Abrupt climate change. The paleoclimate observations, both from sea-floor sediment cores, glacial ice cores, record remarkable periods of rapid change in the distant past, particularly during ice-age glaciation and the transition out of it. Both 

the increasing input of fresh water on top of the ocean, and the warming itself, can 

resist the sinking and global deep circulation described above. Communication between land surface, Arctic, and Atlantic ocean is important to the distribution of 

low-salinity water, and it is correlated with the NAO. Mathematical models and 

computer models of climate predict a slowdown, by up to 50%, of this global circulation in the coming decades. Such changes can be called abrupt in the great scheme 

of things. A new National Research Council study on abrupt climate change is underway this summer. 

The ocean ecosystem represents an important, in some ways dominant, part of 

global photosynthesis and respiration. Ocean circulation and its layering into dense 

deep waters and buoyant surface waters largely control the distribution of life in 

the sea. Disappearance of cod from Atlantic fisheries has a strong relation to overfishing, yet these fish are very sensitive to temperature. Recovery of cod stocks has 

been slow, even when fishing grounds closed down. Salmon fisheries in the north 

Pacific have seen very long (∼50 year) cycles, under a multitude of pressures from 

declining quality of rivers and streams, and climate change (the so-called Pacific 

Decadal Oscillation, or PDO). This summer Coho salmon returned to Lake Washington in great numbers, for the first time in a decade, yet other salmon species 

are now on the endangered list. Overall, 11 of the 15 most important global fisheries 

are in trouble, and the world fish catch has begun to decline after rising six-fold 

between 1950 and 1996. It is a classic case of compounding of causes: over-fishing 

puts stress on fish populations, making them sensitive to modest climate change. 

Storms. Severe storms, hurricanes, tornados, the super-novae of weather, are of 

particular importance. Loss of life in underdeveloped countries and economic loss in 

the U.S. are both striking. A tropical cyclone (dynamically similar to a hurricane) 

in the Indian Ocean hit land in Bangladesh in November 1971; its 30 foot-high 

storm surge inundated the low-lying river delta, causing between 250,000 and 

500,000 fatalities. In the U.S. Hurricane Andrew, in 1992, was one of the most costly natural disasters in history. A direct hit of a major hurricane on Miami could 

cost more than $70B in property damage, owing to the intense coastal population 

increase and development of coastal real estate. Hurricane Mitch, in 1998, showed 

the world how capricious and destructive these storms are in the less-developed 

world. Following an unexpected path southward, then sitting over the mountains of 

Honduras and Nicaragua, Mitch destroyed villages and cost more than 10,000 lives 

through endless rainfall, flooding, and erosion. It nearly destroyed the economies 

and social infrastructure of these countries. 

Hurricane paths and their intensity are correlated with el nin ̃ o cycles, and with 

another key tropical oscillation, the Madden-Julian Oscillation. Hurricanes (and 

tropical cyclones) take their energy from the heat of the tropical ocean. They do so 

surprisingly rapidly, and have been observed to intensify in passing over the Gulf 

Stream and warm eddies (only 50 miles wide) in the Gulf of Mexico. Long lasting 

effects are inland flooding, pollution and sedimentation, which destroy habitats in 

estuaries and marshes. Their connection with global warming is less clear. Model 

studies suggest a 5%–12% increase in hurricane wind-speed for a 2 degree C rise 

in sea-surface temperature, but this is very uncertain. 

Changes in normal weather, for example, more intense rainstorms, have been 

linked to ENSO, NAO and other global climate modes. Possible links exist back to 

global warming through these modes of oscillation, as well as more directly, through 

the changing levels of cloudiness. 

At every turn in this discussion we must weigh the relative advantages of prevention, protection, and treatment in the aftermath. Amartya Sen, an economist at 

Cambridge University, argues that destruction from climate and storms is most severe in the aftermath: that stockpiling of food and creation of jobs programs for the 

poor are important in preserving human life . . . as much so as protection from the 

storm on the day, itself. 

Coastal Ocean. The coastal ocean, the water on the continental shelves and in estuaries, is a small part of the global ocean, yet is the home of roughly one half of 

50

oceanic biological productivity (roughly 25% of global primary biological productivity). It is the site of much diversity, and close involvement with human populations, which are increasingly concentrated near the seacoast. It is also the site of 

80 to 90 percent of the global fish catch. Estuaries, where rivers meet the sea, are 

a sort of pumping machine in which river-flow and tidal stirring combine to suck 

water in from the deep ocean, supplying the region with nutrients: to their benefit, 

estuaries flow in and out at rates much greater than (as much as 50 times) the 

river-flow that drives them. Nutrient sources from rivers are often a small contribution, yet in some estuaries, agricultural practices are loading the estuaries with nitrogen and phosphorus, as well as viruses and bacteria. Chesapeake Bay seasonally 

teeters on the edge of hypoxia, a reduction of oxygen to the point where fish can 

no longer live, when stratification, layering of the water by density, and nutrient 

inflow are both high. 

The coasts are what we call ‘potential vorticity guideways’ along which climate 

change can be signaled rapidly (for example, from an el nin ̃ o event on the Equator, 

poleward along the North and South American Pacific coasts). With a complex of 

local influences, human and natural, the coastal ocean is undergoing rapid change. 

Yet, at the same time, global climate change is strongly felt in this region. A third, 

severe effect is the colonization of the coastal ocean (and lakes and rivers) by new 

species introduced by ship traffic. Ships carry ballast water from one continent to 

another, discharging it and its biological cargo near the coast. The highly diverse 

coastal ecosystem, after evolving in relative isolation, is suddenly invaded. 

It is hard to say in detail what is the time- and space-variability of ocean biology 

and its impacts on the health of humans, fish and algae. This is because we have 

not yet invested in baseline observations of the coastal ocean. But we observe numerous regional hot-spots, as with the dinoflagellate gymnodinium catenatum transported to Australia from Asia, and the Asian clams that have taken over San Francisco Bay. 

Both river- and deep-sea inputs to estuaries change with climate. For example, 

during El Nin ̃ o, riverflow decreases in some regions, thus decreasing the nutrient 

supply from this source. At the same time coastal winds change and this change 

can alter the supply of nutrients to the estuary as more or less nutrient rich water 

is pulled up from the deep ocean to the estuary mouth. Variation of the health of 

fisheries, such as oysters in the Pacific Northwest, has been shown to depend on 

the frequency and strength of El Nin ̃ o. Because of the link to offshore waters, estuaries can also be expected to show evidence of longer term climate change such as 

the PDO. 

Major rivers can exhibit these sensitivities strongly. In the Pacific Northwest the 

largest river is the Columbia. The plume from the Columbia can stretch several 

hundred kilometers from the river mouth—to the Strait of Juan de Fuca in the 

north and to San Francisco in the south. The size of the plume is controlled in 

spring by the amount of snow pack received by the region in the preceding winter. 

For example, snowpack was high in 1999 during la nin ̃ a. In such years, the plume 

floods other nearby estuaries, substantially reducing the salinity and nutrients in 

those estuaries, dramatically altering the environment encountered by emerging 

salmon smolts and entering juvenile crab larvae. In years with lesser snowpack, the 

Columbia plume likely has a more southwestward orientation and may have much 

less effect on local estuaries. Long term effects on the fisheries might be expected 

due to these and other such climate effects and are the subject of current research. 

Human health. Along with colonization of the coastal ocean by new species there 

are increasing problems involving toxins. Harmful algal blooms are occurring more 

frequently. They involve both local human causes (nutrient loading, turbid water), 

and physical ocean changes (temperature, stratification, upwelling, rainfall). While 

mortality is not often widespread, illness and economic loss from closure of shellfish 

beds is. Estimates of the loss to the fishing industry from a single Pfiesteria outbreak, in Chesapeake Bay in 1996, were $20M. The degree to which global climate 

change is involved, is not yet known. 

An example of a pressing public health and economic problem is the diatom in 

the genus Pseudonitzschia that cause domoic acid poisoning (DAP), also known as 

amnesic shellfish poisoning (ASP), and dinoflagellates in the genus Alexandrium 

that are the source of paralytic shellfish poisoning (PSP). Toxic outbreaks along the 

U.S. coast can be highly localized or can extend over several hundred miles and last 

for several months. Both the occurrence of such toxic algal blooms in the offshore 

coastal waters and the delivery of the toxic algae to coastal beaches and to coastal 

estuaries is thought to depend on wind speed and direction as well as coastal water 

properties and hence have a direct link to climate changes along the U.S. coast. 

Near the Strait of Juan de Fuca, the physical oceanography of the coastal circulation has been linked with the appearance of HABs at the coast. A detailed study 

51

of the toxic dinoflagelate gymnodinium breve shows its development in the warm, 

broad shallows of the Gulf of Mexico, and its transport in the Gulf Stream system 

as far as North Carolina, where it has come to shore. 

A major outbreak of cholera developed in coastal Peru, during an extended el nin ̃ o 

event in 1991, and thereafter quickly appeared to neighboring countries. In the first 

3 weeks, 30,000 cases and 114 deaths were reported. Cholera lives dormant in the 

sea as vibrio cholerae, associating itself with mucous membranes of the copepod. 

There is an apparent relationship between warm sea-surface temperature and cholera there and in Bangladesh. The association of climate with disease is thus plausible, yet there are several possible routes, for el nin ̃ o rainfall alters sanitation on 

shore as well as disturbing and warming the coastal ocean. 

Cholera is a disease that may illustrate the association of virulence with transmission rate. In evolutionary biology, Paul Ewald of Amherst College argues that 

cholera and many slowly developing human diseases have evolved so as to maximize 

their own transmission. Thus, with poor sanitation in the under-developed world, 

cholera is rapidly transmitted and very virulent. In countries with good sanitation 

cholera exists in a much more benign strain, adapted to very slow transmission. 

This message suggests that global climate change and human activity (like introduction of ‘exotic’ species by ship traffic) both could conspire to increase the virulence 

of toxic viruses and bacteria in the environment. 

There is a tension throughout this debate on global change, between advocates of 

public health, social infrastructure, economics of the recovery on the one hand, and 

advocates of mitigation of climate change (and its role in disease), and environmental science, on the other. Regardless of the balance struck in resolution of this 

debate, there is value in observing our environment, predicting its future, AND assessing its current behavior. 

New technologies. A remarkable chain of technological discovery has focused on 

observations of the global environment. These are moored and drifting and self-propelled vehicles in the ocean, with a range of sensors for physical, biological and 

chemical substances; orbiting satellites that probe both oceans and atmosphere; seafloor and moored ‘observatories’ that allow us to ‘explore in time’ as well as space. 

The importance of establishing long-term measurement sites for climate studies cannot be overstated (the TAO array of moorings in the Pacific, perhaps the largest scientific instrument ever built, has shown us the inner workings of el nin ̃ o). Molecular 

biology gives a remarkable tool for studying the function and evolution of ecosystems. Computer models of the climate system have become the centerpiece for 

ideas and observations, and computing power continues to increase steadily (though 

sometimes delayed by political constraints). 

These new sensors and platforms give us eyes for viewing climate, computers and 

the internet give us a global central nervous system, but we also need the will to 

observe and understand the environment as it is assaulted by accelerating natural 

and human-induced change.

52

Currents and upwelling of cold, nutrient rich water along the U.S. west coast

Sea-surface temperature (Oregon State University)


718rhin1.eps
53

Evidence of a red tide on the West Florida Shelf: Nov 1978, red = chlorophyll

a > 3 μg/l (Florida Marine Inst.)

Northern Atlantic (Labrador Sea) salinity at three depths (2000m, 3500m, 1500m 

top to bottom). Salinity declines as fresh water input at the surface has increased 

with intense, cold forcing by the North Atlantic Oscillation. I. Yashayaev, J. Lazier 

Bedford Inst. of Oceanography, P. Rhines (Univ. of Washington)


718rhin2.eps 718rhin3.eps
54

Dissolved nitrate in the Atlantic Ocean, along a section from Antarctica (left) to Iceland. High concentrations of this nutrient occur deep in the ocean, and in the Southern Ocean. Near the surface nitrate is almost absent, evidence of active ecosystem 

growth at the top of the ocean. The global ocean circulation must bring nitrate up 

to the surface, and controls the distribution of life (WOCE program). 


718rhin4.eps
55

CLIMATE POLICY—FROM RIO TO KYOTO: A POLITICAL ISSUE FOR 2000—AND BEYOND

Hoover Institution Essay by S. Fred Singer 

Executive Summary 

Within the United States, global warming and related policy issues are becoming 

increasingly contentious, surfacing in the presidential contests of the year 2000 and 

beyond. They enter into controversies involving international trade agreements, 

questions of national sovereignty versus global governance, and ideological debates 

about the nature of future economic growth and development. On a more detailed 

level, determined efforts are under way by environmental groups and their sympathizers in foundations and in the federal government to restrict and phase out the 

use of fossil fuels (and even nuclear reactors) as sources of energy. Such measures 

would reduce greenhouse-gas emissions into the atmosphere but also effectively 

deindustrialize the United States. 

International climate policy is based on the 1997 Kyoto Protocol, which calls on 

industrialized nations to carry out, within one decade, drastic cuts in the emission 

of greenhouse gases (GHG) that stem mainly from the burning of fossil fuels. The 

Protocol is ultimately based on the 1996 Scientific Assessment Report issued by the 

Intergovernmental Panel on Climate Change (IPCC), a U.N. advisory body. The 

IPCC’s main conclusion, featured in its Summary for Policymakers (SPM), states 

that ‘‘the balance of evidence suggests a discernible human influence on global climate.’’ This widely quoted, innocuous-sounding but ambiguous phrase has been misinterpreted by many to mean that climate disasters will befall the world unless 

strong action is taken immediately to cut GHG emissions. 

This essay documents the inadequate science underlying the IPCC conclusions, 

traces how these conclusions were misinterpreted in 1996, and how this led to the 

Kyoto Protocol. I also discuss some fatal shortcomings of the Protocol and the political and ideological forces driving it. 

The IPCC conclusion is in many ways a truism. There certainly must be a human 

influence on some features of the climate, locally if not globally. The important question—the focus of scientific debate—is whether the available evidence supports the 

results of calculations from the current General Circulation Models (GCMs). Unless 

validated by the climate record, the predictions of future warming based on theoretical models cannot be relied on. As demonstrated in this essay, GCMs are not 

able to account for observed climate variations, which are presumably of natural origin, for the following reasons:

1. To begin with, GCMs assume that the atmospheric level of carbon dioxide will 

continue its increase (at a greater rate than is actually observed) and will more 

than double in the next century. Many experts doubt that this will ever happen, as the world proceeds on a path of ever-greater energy efficiency and as 

low-cost fossil fuels become depleted and therefore more costly.

2. Next, one must assume that global temperatures will really rise to the extent 

calculated by the conventional theoretical climate models used by the IPCC. 

Observations suggest that any warming will be minute, will occur mainly at 

night and in winter, and will therefore be inconsequential. The failure of the 

present climate models is likely due to their inadequate treatment of atmospheric processes, such as cloud formation and the distribution of water vapor 

(which is the most important greenhouse gas in the atmosphere).

3. The putative warming has been labeled as greater and more rapid than anything experienced in human history. But a variety of historical data contradicts 

this apocalyptic statement. As recently as 1,000 years ago, during the ‘‘Medieval climate optimum,’’ Vikings were able to settle Greenland. Even higher temperatures were experienced about 7,000 years ago during the much-studied 

‘‘climate optimum.’’

The IPCC’s Summary for Policymakers tries hard to minimize the inadequacy of 

the GCMs to model atmospheric processes and reproduce the observed climate variations. For example, the SPM does not reveal the fact that weather satellite data, 

the only truly global data we have, do not show the expected atmospheric warming 

trend; the existence of satellites is not even mentioned. 

The scientific evidence for a presumed ‘‘human influence’’ is spurious and based 

mostly on the selective use of data and choice of particular time periods. Phrases 

that stress the uncertainties of identifying human influences were edited out of the 

approved final draft before the IPCC report was printed in May 1996. 

A further misrepresentation occurred in July 1996 when politicians, intent on establishing a Kyoto-like regime of mandatory emission controls, took the deceptively 

worded phrase about ‘‘discernible human influence’’ and linked it to a catastrophic 

56

* The information referred to has been retained in the Committee files. 

future warming—something the IPCC report itself specifically denies. The IPCC 

presents no evidence to support a substantial warming such as calculated from theoretical climate models. 

The essay also demonstrates that global warming (GW), if it were to take place, 

is generally beneficial for the following reasons:

1. One of the most feared consequences of global warming is a rise in sea level 

that could flood low-lying areas and damage the economy of coastal nations. 

But actual evidence suggests just the opposite: a modest warming will reduce 

somewhat the steady rise of sea level, which has been ongoing since the end 

of the last Ice Age—and will continue no matter what we do as long as the 

millennia-old melting of Antarctic ice continues.

2. A detailed reevaluation of the impact of climate warming on the national economy was published in 1999 by a prestigious group of specialists, led by a Yale 

University resource economist. They conclude that agriculture and timber resources would benefit greatly from a warmer climate and higher levels of carbon dioxide and would not be negatively affected as had previously been 

thought. Contrary to the general wisdom expressed in the IPCC report, higher 

CO2 levels and temperatures would increase the GNP of the United States and 

put more money in the pockets of the average family.

But even if the consequences of a GW were harmful, there is little that can be 

done to stop it. ‘‘No-regrets’’ policies of conservation and adaptation to change are 

the most effective measures available. Despite its huge cost to the economy and consumers, the emission cuts envisioned by the Kyoto Protocol would be quite ineffective. Even if it were observed punctiliously, its impact on future temperatures would 

be negligible, only 0.05°C by 2050 according to IPCC data. It is generally agreed 

that achieving a stable level of GHGs would require much more drastic emission 

reductions, including also by developing nations. To stabilize at the 1990 level, the 

IPCC report calls for a 60 to 80 percent reduction—about twelve Kyotos on a worldwide basis! 

Finally, the essay attempts to trace the various motivations that led to the Kyoto 

Protocol. It concludes that U.S. domestic politics rather than science or economics 

will decide the fate of the Protocol; in particular, the presidential elections of 2000 

will determine whether the United States ultimately ratifies the Protocol, which 

would be essential for its global enactment. Conversely, informed debate about the 

Protocol can influence the outcome of the elections. 

YALE UNIVERSITY, SCHOOL OF FORESTRY AND ENVIRONMENTAL STUDIES, 

New Haven, Connecticut, July 12, 2000.

Senator JOHN MCCAIN

Committee on Commerce, Science, and Transportation 

United States Senate 

Washington, D.C.

Dear Senator McCain:

In response to your invitation to speak to the Senate Committee on Commerce, 

Science, and Transportation, I would like to submit the following material as part 

of the written record. Over the last five years, I have been working with a distinguished group of researchers from across the United States measuring the impacts 

of climate change on the U.S. economy. The initial study, edited by Robert 

Mendelsohn and James Neumann and published in 1999 by Cambridge University 

Press, was entitled ‘‘The Impact of Climate Change on the United States Economy.’’ A subsequent book entitled ‘‘Global Warming and the American Economy: A Regional Assessment of Climate Change’’ is being prepared for publication at present. 

Following is the introduction and the synthesis of results of this new book.* 

The critical insight of both of these new books is that adaptation matters. Empirical research indicates that households and firms will respond to climate change and 

reduce damages and enhance benefits. Coupled with more careful modeling of dynamic effects, carbon fertilization, and ecosystem change, the new results are far 

more optimistic than the old studies. These estimates do not include nonmarket effects in health, ecosystem change, and aesthetics, but it is not clear that these nonmarket effects will be large in the United States. 

57

Climate change is likely to result in small net benefits for the United States over 

the next century. The primary sector that will benefit is agriculture. The large gains 

in this sector will more than compensate for damages expected in the coastal, energy, and water sectors, unless warming is unexpectedly severe. Forestry is also expected to enjoy small gains. Added together, the United States will likely enjoy 

small benefits of between $14 and $23 billion a year and will only suffer damages 

in the neighborhood of $13 billion if warming reaches 5C over the next century. Recent predictions of warming by 2100 suggest temperature increases of between 1.5 

and 4C, suggesting that impacts are likely to be beneficial in the U.S. 

The impact of warming depends upon the initial temperature of each region. With 

mild warming of 1.5 C, every region benefits from warming. The average American 

would enjoy benefits of about $100/yr. However, with 2.5C warming, the cooler 

northern regions of the country benefit far more than the warmer southern regions. 

The average citizen in the north would enjoy benefits of about $80/yr whereas southern citizens would enjoy average benefits of only about $6/yr. If warming rises to 

5C, the benefits in the north shrink to about $40 per person, but citizens in the 

south may suffer damages from $120 to $370 per person. 

In summary, climate change does not appear to be a major threat to the United 

States for the century to come. There is little motivation for expensive crash programs to curb short term emissions of greenhouse gases. The focus of mitigation policy should remain on inexpensive ways to control global emissions over the next century. 

Sincerely, 

ROBERT MENDELSOHN, 

Edwin Weyerhaeuser Davis Professor.

TABLE 1

National Impacts 

Sector Old Results New Results 

Agriculture –17.5 to –1.1 19.6

Forestry –3.3 to –0.7 3.7

Water –7.0 to –15.6 –2.2

Coastal –7.0 to –12.2 –0.2

Energy –9.9 to –0.5 –5.8

TOTAL –44.7 to –13.8 15.1

Sources: Nordhaus [1991], Cline [1992], Fankhauser [1995], Tol [1995], 

Mendelsohn [2000]. 

Regional Impacts 

(Billions of USD/yr)

2.5C, 7% Precipitation Scenario 

Sector 

Region Agr For Ene Coa Wat Total 

Northeast 2.6 1.9 –0.4 –0.1 0.0 4.0

Midwest 5.4 1.1 –0.1 –0.0 –0.0 6.4

N. Plains 2.8 0.6 –0.1 –0.0 –0.1 3.2

Northwest 1.1 –0.1 1.4 –0.0 –1.7 0.7

Southeast 4.2 –0.8 –3.0 –0.1 –0.0 0.3

S. Plains 2.1 0.6 –2.4 –0.0 –0.2 0.1

Southwest 1.4 0.4 –1.2 –0.0 –0.2 0.4 

National 19.6 3.7 –5.8 –0.2 –2.2 15.1

58

Regional Impacts 

(USD/per capita/yr) 

Region 

Climate Scenario 

1.5C 

15%P 

2.5C 

7%P 

5.0C 

0%P

Northeast 28 52 19

Midwest 84 84 36

N Plains 539 359 75

Northwest 410 80 –369

Southeast 91 6 –122

S. Plains 129 5 –266 

Southwest 80 11 –134

National 97 52 –56

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