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37–414 PDF 2007

CLIMATE CHANGE: ARE GREENHOUSE

GAS EMISSIONS FROM HUMAN

ACTIVITIES CONTRIBUTING TO

THE WARMING OF THE PLANET?

HEARING

BEFORE THE

SUBCOMMITTEE ON ENERGY AND AIR QUALITY

OF THE

COMMITTEE ON ENERGY AND

COMMERCE

HOUSE OF REPRESENTATIVES

ONE HUNDRED TENTH CONGRESS

FIRST SESSION

MARCH 7, 2007

Serial No. 110–14

(

Printed for the use of the Committee on Energy and Commerce

energycommerce.house.gov

COMMITTEE ON ENERGY AND COMMERCE

JOHN D. DINGELL, Michigan, Chairman

HENRY A. WAXMAN, California

EDWARD J. MARKEY, Massachusetts

RICK BOUCHER, Virginia

EDOLPHUS TOWNS, New York

FRANK PALLONE, JR., New Jersey

BART GORDON, Tennessee

BOBBY L. RUSH, Illinois

ANNA G. ESHOO, California

BART STUPAK, Michigan

ELIOT L. ENGEL, New York

ALBERT R. WYNN, Maryland

GENE GREEN, Texas

DIANA DEGETTE, Colorado

Vice Chairman

LOIS CAPPS, California

MIKE DOYLE, Pennsylvania

JANE HARMAN, California

TOM ALLEN, Maine

JAN SCHAKOWSKY, Illinois

HILDA L. SOLIS, California

CHARLES A. GONZALEZ, Texas

JAY INSLEE, Washington

TAMMY BALDWIN, Wisconsin

MIKE ROSS, Arkansas

DARLENE HOOLEY, Oregon

ANTHONY D. WEINER, New York

JIM MATHESON, Utah

G.K. BUTTERFIELD, North Carolina

CHARLIE MELANCON, Louisiana

JOHN BARROW, Georgia

BARON P. HILL, Indiana

JOE BARTON, Texas

Ranking Member

RALPH M. HALL, Texas

J. DENNIS HASTERT, Illinois

FRED UPTON, Michigan

CLIFF STEARNS, Florida

NATHAN DEAL, Georgia

ED WHITFIELD, Kentucky

BARBARA CUBIN, Wyoming

JOHN SHIMKUS, Illinois

HEATHER WILSON, New Mexico

JOHN B. SHADEGG, Arizona

CHARLES W. ‘‘CHIP’’ PICKERING,

Mississippi

VITO FOSSELLA, New York

STEVE BUYER, Indiana

GEORGE RADANOVICH, California

JOSEPH R. PITTS, Pennsylvania

MARY BONO, California

GREG WALDEN, Oregon

LEE TERRY, Nebraska

MIKE FERGUSON, New Jersey

MIKE ROGERS, Michigan

SUE WILKINS MYRICK, North Carolina

JOHN SULLIVAN, Oklahoma

TIM MURPHY, Pennsylvania

MICHAEL C. BURGESS, Texas

MARSHA BLACKBURN, Tennessee

PROFESSIONAL STAFF

DENNIS B. FITZGIBBONS, Chief of Staff

GREGG A. ROTHSCHILD, Chief Counsel

SHARON E. DAVIS, Chief Clerk

BUD ALBRIGHT, Minority Staff Director

(II)

(III)

SUBCOMMITTEE ON ENERGY AND AIR QUALITY

RICK BOUCHER, Virginia, Chairman

G. K. BUTTERFIELD, North Carolina

Vice Chairman

CHARLIE MELANCON, Louisiana

JOHN BARROW, Georgia

HENRY A. WAXMAN, California

EDWARD J. MARKEY, Massachusetts

ALBERT R. WYNN, Maryland

MIKE DOYLE, Pennsylvania

JANE HARMAN, California

TOM ALLEN, Maine

CHARLES A. GONZALEZ, Texas

JAY INSLEE, Washington

TAMMY BALDWIN, Wisconsin

MIKE ROSS, Arkansas

DARLENE HOOLEY, Oregon

ANTHONY D. WEINER, New York

JIM MATHESON, Utah

JOHN D. DINGELL, Michigan (ex officio)

J. DENNIS HASTERT, Illinois,

Ranking Member

RALPH M. HALL, Texas

FRED UPTON, Michigan

ED WHITFIELD, Kentucky

JOHN SHIMKUS, Illinois

JOHN B. SHADEGG, Arizona

CHARLES W. ‘‘CHIP’’ PICKERING,

Mississippi

STEVE BUYER, Indiana

MARY BONO, California

GREG WALDEN, Oregon

MIKE ROGERS, Michigan

SUE WILKINS MYRICK, North Carolina

JOHN SULLIVAN, Oklahoma

MICHAEL C. BURGESS, Texas

JOE BARTON, Texas (ex officio)

PROFESSIONAL STAFF

SUE SHERIDAN, Chief Counsel

LAURA VAUGHT, Policy Coordinator

DAVID MCCARTHY, Minority Chief Counsel

(V)

C O N T E N T S

Page

Hon. Rick Boucher, a Representative in Congress from the Commonwealth

of Virginia, opening statement ............................................................................ 1

Hon. J. Dennis Hastert, a Representative in Congress from the State of

Illinois, opening statement .................................................................................. 2

Hon. John D. Dingell, a Representative in Congress from the State of Michigan, opening statement ....................................................................................... 3

Hon. John Shimkus, a Representative in Congress from the State of Illinois,

opening statement ................................................................................................ 5

Hon. Tammy Baldwin, a Representative in Congress from the State of Wisconsin, opening statement ................................................................................... 6

Hon. Michael C. Burgess, a Representative in Congress from the State of

Texas, opening statement .................................................................................... 7

Hon. Joe Barton, a Representative in Congress from the State of Texas,

prepared statement .............................................................................................. 8

WITNESSES

James W. Hurrell, director, Climate and Global, Dynamics Division, National

Center for Atmospheric Research, Boulder, CO ................................................ 10

Prepared statement .......................................................................................... 91

Michael Oppenheimer, professor, geosciences and international affairs,

Princeton University, Woodrow Wilson School, Princeton, NJ ........................ 12

Prepared statement .......................................................................................... 75

Gabriele Hegerl, associate research professor, Earth and Ocean Sciences Division, Duke University, Durham, NC .................................................................. 13

Prepared statement .......................................................................................... 65

Roni Avissar, professor and chair, Department of Civil and Environmental

Engineering, Duke University, Durham, NC ..................................................... 15

Prepared statement .......................................................................................... 49

John R. Christy, professor and director, Earth System Science Center,

NSSTC, University of Alabama in Huntsville, Huntsville, AL ........................ 17

Prepared statement .......................................................................................... 54

SUBMITTED MATERIAL

Intergovernmental Panel on Climate Change, ‘‘Climate Change 2007: The

Physical Science Basis’’ ........................................................................................ 115

(1)

CLIMATE CHANGE: ARE GREENHOUSE GAS

EMISSIONS FROM HUMAN ACTIVITIES CONTRIBUTING TO THE WARMING OF THE

PLANET?

WEDNESDAY, MARCH 7, 2007

HOUSE OF REPRESENTATIVES,

SUBCOMMITTEE ON ENERGY AND AIR QUALITY,

COMMITTEE ON ENERGY AND COMMERCE,

Washington, DC.

The subcommittee met, pursuant to call, at 10:00 a.m., in room

2322 of the Rayburn House Office Building, Hon. Rick Boucher

(chairman) presiding.

Members present: Representatives Butterfield, Melancon, Barrow, Waxman, Markey, Inslee, Baldwin, Ross, Hooley, Dingell,

Hastert, Upton, Whitfield, Shimkus, Buyer, Walden, Sullivan, Burgess and Barton.

Staff present: Sue Sheridan, Laura Vaught, Bruce Harris, Lorie

Schmidt, Chris Treanor, David McCarthy, Kurt Bilas, and Peter

Kielty.

OPENING STATEMENT OF HON. RICK BOUCHER, A REPRESENTATIVE IN CONGRESS FROM THE COMMONWEALTH

OF VIRGINIA

Mr. BOUCHER. The subcommittee will come to order.

Today we examine the scientific evidence regarding global temperature changes and their relationship to human activity. At a

later date the subcommittee will examine scientific opinion on the

effects of temperature changes on weather patterns, ocean levels

and habitat.

The scientists on our panel today are all noted experts in their

field and we welcome them to the subcommittee this morning.

Their presentations will address the questions of whether global

temperatures are increasing and to what extent any changes in

temperatures are a consequence of human activity rather than natural climate variability and how future temperatures may be affected by current and future human activity. Over the past several

decades, a vigorous debate has occurred over whether global temperatures are rising and whether any increases are being caused

by human activity. The scientific opinion now appears to be solidifying with widespread agreement that temperatures are rising and

that human activity is the principle cause. The recently released

Intergovernmental Panel on Climate Change report reflects that

consensus. It concludes with more than 90 percent certainty that

2

temperatures are rising and that human contributions are causing

most of the observed increases. This conclusion stands in sharp

contrast with the panel report of several years ago reaching the

same conclusions but only with a certainty of 66 percent.

Today’s witnesses will comment on the IPCC report and on relevant research findings and conclusions which can be drawn from

those research findings. I appreciate the attendance this morning

of our expert witnesses and I very much look forward to hearing

from them.

We have at about 11:00 this morning a joint meeting between the

House of Representatives and the Senate for the purpose of hearing

from a visiting head of state, and under the rules of the House, we

will not be able to continue the subcommittee hearing during the

pendency of that joint meeting between the House and the Senate

and so Mr. Hastert and I have agreed that what we will do is, go

as far as we can in this hearing, recess during the pendency of the

joint hearing between the House and Senate and then come back

to finish this hearing at such point as that joint meeting of the

House and Senate has been concluded.

With those comments, I am pleased now to recognize the ranking

member of this subcommittee, the gentleman from Illinois, Mr.

Hastert, for 5 minutes.

OPENING STATEMENT OF HON. J. DENNIS HASTERT, A REPRESENTATIVE IN CONGRESS FROM THE STATE OF ILLINOIS

Mr. HASTERT. Thank you, Chairman Boucher.

This morning we begin the science of global warming. Today’s

hearing is actually the beginning, in my view, of a thorough examination we must perform before moving forward with legislation

proposing far-reaching economic implications. In fact, Mr. Chairman, I know you wanted to hold this hearing earlier in the process

but you were forced to reschedule due to last month’s severe winter

storms, an irony lost on few. We just couldn’t get the witnesses

here.

The question before us concerns the nature, extent and rate of

global warming that has been observed and how human emissions

of greenhouse gases figure into these observations. As we dig into

the questions of man’s contribution to global warming, I believe it

is essential that we develop a broader perspective on what we

know about climate effects, both natural and manmade.

Many climate scientists acknowledge the deep complexity and

limits of human knowledge of the climate system. This contrasts

with the overly simplistic reporting of global warming and the climate change risks that we see in the mass media, whose treatment

of the subject is often superficial and sensational. For policymakers, that is a dangerous combination.

Mr. Chairman, we must avoid falling prey to the sensational. We

must not miss out on the important questions or the practical opportunities that can help us address the challenges of global warming in an economically prudent fashion.

In 2001, the National Research Council released its reported entitled ‘‘Climate Change Science and Analysis of Some Key Questions.’’ The NRC made an important observation in their report,

and here is a direct quote: ‘‘The most valuable contribution U.S.

3

scientists can make is to continually question basic assumptions

and conclusions, promote clear and careful appraisal and presentation of the uncertainties about climate change as well as those

areas in which science is leading robust conclusion.’’

We should heed the advice of our top scientists. We need to keep

asking, are we focused on the right science questions, are we focused on the right policy issues. For example, should we be concerned with just our own unilateral steps to reverse climate trends

or should we address the effect of climate change more broadly as

it relates to regions and local areas regardless of the temperature?

How should we understand human influence in this broader context of the climate?

I am hopeful the witnesses today can shed some light on these

questions, that they can help us determine if we are looking at the

issue properly. I am particularly interested in hearing whether we

have a good handle on the relative contribution of greenhouse emissions to climate change compared with other human and natural

resources. I would like to learn about the limits of our ability to

attribute greenhouse gas emissions to global warming and what is

needed to improve that ability. I would like to learn more about

where the latest research is leading and how that might be changing the assumptions scientists have had about the issue.

Last month the United States Intergovernmental Panel on Climate Change said, in effect, global warming is unequivocal; details

to follow. I happen to believe, however, that saying global warming

is unequivocal doesn’t end the discussion; it begins it. How exactly

do man’s labors and industry connect to that warning? Is that connection the most relevant issue for us to address? Can we effectively change climate, address climate without forsaking our ability

to deal with the other challenges of nature and human development that will confront us? We have to adapt to climate change no

matter what is the cause, it is the way it has been forever, and energy policy plays an important role in that ability to address it. Energy animates our economic vitality. It is that vitality that gives us

the ability to meet the challenges that nature delivers upon us.

Let me thank the distinguished scientists before us today who

have taken time from their busy schedule to attend the hearing. I

look forward to your insights in these matters and I thank you, Mr.

Chairman.

Mr. BOUCHER. Thank you very much, Mr. Hastert.

The gentleman from Michigan, the chairman of the full committee, Mr. Dingell, is recognized for 5 minutes.

OPENING STATEMENT OF HON. JOHN D. DINGELL, A REPRESENTATIVE IN CONGRESS FROM THE STATE OF MICHIGAN

Mr. DINGELL. Mr. Chairman, thank you for your kindness and

thank you for calling a very worthwhile series of hearings on climate change. It will be most helpful as we go forward to the consideration of this legislation.

Now, I would like to also thank our panel. Ladies and gentlemen,

thank you for being here and thank you for your time and for your

assistance to the committee.

4

Today we will examine the scientific question of whether greenhouse gas emissions from human activities are contributing and

will continue to contribute to a warming of this planet. While many

of us have had significant doubts about the question in the past,

today it seems to us that science on the question has been settled.

The extent of scientific consensus on this matter is well reflected

by the recently published findings of the Intergovernmental Panel

on Climate Change, IPCC, which was just released and entitled

‘‘Summary for Policymakers’’ for its fourth assessment report. The

report was produced by some 600 authors from 40 countries, over

620 expert reviewers and a large number of government reviewers

also participated. Representatives from 113 governments, including

the United States, reviewed and revised the summary line by line

before adopting it and accepting the underlying report.

The IPCC found that the warming of the climate system is unequivocal and that most of the observed increase in globally average temperatures since the mid–20th century is very likely due to

the observed increase in anthropogenic greenhouse gas emissions.

By ‘‘very likely’’ the IPCC means a nine in 10 chance. For the future, the IPCC found that changes in the global climate system in

the 21st century would very likely be larger than those observed

in the 20th century. Indeed, even the administration seems to be

in agreement with this point. Right after the IPCC report was released, Secretary of Energy Samuel Bodman was reported as saying, ‘‘We are very pleased with it. We are embracing it. We agree

with it.’’ He went on to add that ‘‘human activity is contributing

to the changes in our Earth’s climate and that issue is no longer

up for debate.’’

Last month I had a fascinating discussion with some of the scientists responsible for the IPCC report. I asked detailed questions,

some technical and some challenging. The answers I received were

forthright. They explained that they had looked at changes in solar

radiation, volcanic eruptions, urban heat islands and many other

phenomena that are contributing to climate change. They explained

that some of these factors are important for local temperature but

that the only explanation for the large increase in global temperatures are the greenhouse gases which we are adding to the atmosphere. The scientists explained that there are some areas where

scientific uncertainty exists. On the central question of man’s contribution to the increase of global temperature due to greenhouse

gas emissions, however, the issue is clear.

It is important for the committee to probe renowned scientists to

better understand what the science is telling us and how we are

to answer the questions that are now before us. We need to find

out where the science gives us clear answers and where the science

gives us fuzzy answers. Today we are focusing on the threshold

question of the extent to which greenhouse gas emissions from

human activities are causing an increase in global temperature. At

a future hearing we will explore the consequences of global warming for the Earth’s systems. In other words, we will be asking why

it matters that we are increasing global temperatures.

In closing, Mr. Chairman, I hope that the members will use this

opportunity to ask tough questions and to seek answers for any uncertainty they may have about the science of climate change.

5

I thank you again for the hearings, and I thank also again our

panel for their assistance to us.

I yield back the balance of my time.

Mr. BOUCHER. Thank you, Mr. Dingell.

Mr. Shimkus for 5 minutes.

OPENING STATEMENT OF HON. JOHN SHIMKUS, A REPRESENTATIVE IN CONGRESS FROM THE STATE OF ILLINOIS

Mr. SHIMKUS. Thank you, Mr. Chairman, and at the risk of trying to be as funny as my friend Mr. Markey, who I had great discussions with yesterday and then after the hearing, I was hesitant

to say this, Ed, but we had hearings like this over many years and

it was always in July, and if I heard Ed say it once, I heard him

say it a hundred times: it is ironic that we are having a global

warming hearing on the hottest day, in the hottest month, in the

hottest year and the hottest century. It is snowing on March 7 and

I would venture to say that it has been a pretty the cold February

and March than what we have been used to in the last couple

years. So for levity’s sake, I throw that out, Ed, and Ed and I are

going to have a good fun time in the next couple years in this

whole debate.

I want to draw attention also to the February 5 Wall Street Journal editorial and I think this sums up kind of where a lot of us are:

‘‘The IPCC report should be understood as one more contribution

to the warming debate, not some definitive last word that justifies

radical policy change. It can be hard to keep one’s head when everyone else is predicting the apocalypse but that is all the more

reason to keep cool and focused on actual science,’’ and that is why

you are here today. We hope to ask and hear from you noted scientists.

Most of us aren’t that knowledgeable in the science. We are laymen who will try to move the country into good policy direction.

There are always unintended consequences of legislative action

which could be devastating and so we have to try to find balance.

We want this to be a deliberative process. I think the committee

is taking it in all the seriousness that is intended. We want to

make sure we understand the reliability of knowledge and do our

job in making sure we are gathering all the evidence from all the

factors. This is our second hearing of this committee and we have

many more to go. We appreciate your attendance. I look forward

to hearing your testimony.

Mr. Chairman, I yield back my time.

Mr. BOUCHER. Thank you very much, Mr. Shimkus.

Mr. Waxman from California for 3 minutes.

Mr. WAXMAN. Thank you, Mr. Chairman. I am going to forego an

opening statement in exchange for a lengthier time to question the

witnesses.

Mr. BOUCHER. Thank you, Mr. Waxman, and I would note that

any member who desires to waive his opening statement will have

3 minutes added to his questioning time for the panel of witnesses.

The gentleman from Massachusetts, Mr. Markey, for 3 minutes.

Mr. MARKEY. I pass.

Mr. BOUCHER. Mr. Markey waives.

6

For 3 minutes, the gentleman from Washington, Mr. Inslee, is

recognized.

Mr. INSLEE. I will pass.

Mr. BOUCHER. Mr. Inslee passes.

Mr. Barrow from Georgia.

Mr. BARROW. I will pass.

Mr. BOUCHER. Mr. Barrow also passes.

The gentlewoman from Wisconsin, Ms. Baldwin, for 3 minutes.

OPENING STATEMENT OF HON. TAMMY BALDWIN, A REPRESENTATIVE IN CONGRESS FROM THE STATE OF WISCONSIN

Ms. BALDWIN. Thank you, Mr. Chairman.

I want to express my gratefulness for this opportunity in this

hearing today because for years undue political considerations have

really kept us from reaching this point. Naysayers ignored clear

warnings that human activity was creating significant changes in

regional and global climate. They dismissed calls for action, claiming that alarmists were simply trying to focus attention on everything green. But the tides have turned and those of us who long

ago committed ourselves to focusing on global changes in climate

now have the backing of the congressional leadership and the international community in calling for action.

The IPCC report is of vast importance. Not only does it confirm

that climate change is real but it also confirms that human activities are the main cause. This report is not the work of politicians

nor the work of zealots. Rather, it is a consensus of the scientific

community of representatives from more than 113 countries of

nearly 600 authors. These are the experts who have been to the top

of the mountains, the bottom of the oceans, across deserts and icy

fields, crisscrossing our planet to analyze the Earth’s changing climate. In reaching their conclusions, they have surveyed climate

data, observed geographic conditions and evaluated severe weather

trends. These scientists have clearly done their work uninfluenced

by politics or personal agenda and now it is time for us to do ours.

We must take the knowledge and the data that has been presented to us and create sound policy that will result in a reduction

of our greenhouse gas emissions. It won’t be easy. We have questions to answer. For instance, what role will renewable energy play

in our future and how can we begin to conserve energy now

through efficient changes in the way we power our homes, operate

our appliances or run our vehicles. While there are challenges

ahead, our Nation, our businesses, our communities are in the best

position to reshape our future. We understand the consequences of

inaction and we are prepared to take steps necessary to preserve

our planet for future generations. As stewards, protecting our environment has been our responsibility and now we are making it a

priority.

I look forward to hearing from our experts here today about how

they reached their conclusions about their recommendations and

for how we can reverse course and reduce our greenhouse gases,

ensuring a healthy planet for generations to come.

Thank you, Mr. Chairman, again. I yield back the balance of my

time.

7

Mr. BOUCHER. Thank you, Ms. Baldwin.

Mr. Buyer for 3 minutes.

Mr. BUYER. I pass.

Mr. BOUCHER. Mr. Buyer passes.

Mr. Upton for 3 minutes.

Mr. UPTON. I pass.

Mr. BOUCHER. Mr. Upton passes.

Mr. Burgess for 3 minutes.

OPENING STATEMENT OF HON. MICHAEL C. BURGESS, A

REPRESENTATIVE IN CONGRESS FROM THE STATE OF TEXAS

Mr. BURGESS. Thank you, Mr. Chairman, and I too want to

thank you for convening this hearing. I think these hearings have

been extremely informative and this morning’s science hearing is

essential to what we are doing here on the legislative process so

I am glad we were able to reschedule this hearing, canceled last

month due to an ice storm and put in jeopardy by a snowstorm but

it is a timely hearing nevertheless.

I am really kind of puzzled why this wasn’t actually our first

hearing. Instead of starting from the beginning with the science,

we started with the solutions, cap and trade proposals and carbon

sequestration, but now that we have finally gotten around to it,

this is critical for part of our discussion.

If I could, I think have one slide to put up on the screen in the

brief time allotted to me, and that is not it. Well, we will get this

handed out. But according to EPA data, water vapor accounts for

95 percent of greenhouse gases. There it is.

[Slide shown.]

Ocean biologic activity, volcanoes, decaying plants are an additional 4.72 percent and the last small sliver is the human contribution, less than one-third of 1 percent. But today we are going to

focus like a laser beam on that less than one-third of 1 percent but

I think it is important that we don’t forget the context in which we

are working. The human additions to the greenhouse gas emissions

come from multiple sources including livestock, land use changes,

fire suppression systems, electricity plants and tailpipes. I believe

that Dr. Avissar from Duke University will be focusing his testimony on this broader context.

I realize that this is a topic that will be addressed in a future

hearing by the subcommittee but I think it is important that as we

begin to examine the causes of global climate change, we not forget

the economic consequences of policy decisions made by this body as

we look at this legislation.

Regardless of the reason, whether you are a fan of global warming, of peak oil or just feel it is a cause for a national security concern, removing some carbon from the economic equation is an idea

that has merit, but at the same time, we must not sacrifice our

economy as we make that transition, because after all, it is the

health of our economy that will allow us to make that transition,

and I think that is an important point to keep in mind but also I

would just share this concern: Global warming and climate change

are not interchangeable terms. They are not synonymous and we

are going to hear more in this hearing about the differences from

some of today’s witnesses, and I believe Dr. Christy is going to be

8

talking about as we discussed some in our oversight hearing last

year.

Thank you, Mr. Chairman, and I will yield back my remaining

12 seconds.

Mr. BOUCHER. Thank you very much, Mr. Burgess.

Mr. Shadegg from Arizona is recognized for 3 minutes.

Mr. SHADEGG. Mr. Chairman, I will pass other than to commend

you for holding this hearing. I think it is important that we look

at the science, both the science as to the cause of whatever warming is occurring and the science as to how we can deal with it, and

I commend you.

Mr. BOUCHER. Thank you very much, Mr. Shadegg.

That concludes the time for opening statements. Statements for

the record will be accepted at this time.

[The prepared statement of Mr. Barton follows:]

PREPARED STATEMENT OF HON. JOE BARTON, A REPRESENTATIVE IN CONGRESS FROM

THE STATE OF TEXAS

Thank you, Chairman Boucher, for this initial hearing on the question of man’s

contribution to global warming.

I commend you and Chairman Dingell for putting together a series of hearings

on global warming science and policy. Our committee’s tradition of open process has

historically enabled us to take on the tough economic and public health issues despite our geographic, ideological, and political diversity.

We are addressing global warming, but we’re not doing it in a vacuum. We’re also

charged with make sure that people in America have the energy that powers our

jobs and, through them, our people’s opportunity to succeed. If we do our jobs, people will keep their jobs.

I hope today’s hearing and the ones that follow will help each of us reach rational

conclusions, based on real evidence, about the reliability of our knowledge that CO2

has the sort of impact on planetary temperature as people say.

It’s important to recognize that this is not about the weather on any given day.

When we met to examine the dubious statistical validity of some global warming

forecasts last summer, it was very hot. I think we picked one of the hottest days

of the year. Today the weather is uncharacteristically cold. I’m sure some would prefer to wait until the weather matches the theory, but this is serious business and

I hope we can each concede that any day’s weather has nothing to do with the issue.

There has been significant scientific debate about this issue, including discussion

before this committee. In last summer’s hearings, we asked about the historical temperature records and other climate observations. We asked whether the most politically influential modeling conclusions were adequately supported by those observations.

I said then that I accept that the science on this matter is uneven, uncertain, and

evolving. That certainly hasn’t changed, but now we seem to be pressuring ourselves, or someone is pressuring us, to legislate first and get the facts later. I hope

we won’t do that. I want to make sure we get the best information available so we

have a full and accurate definition of the problem before we start making decisions

that will be among the toughest of our careers.

The key question we face is how our decisions affect the lives of the people who

send us here. They expect us to make decisions, and they do not expect us to make

wrong ones.

I will follow the guidance of my friend, Chairman Dingell: ‘‘First, do no harm.’’

We have to be clear about the issues before us. Discussion of capping CO2 often

misses an essential fact. Carbon dioxide, unlike carbon monoxide and other compounds ending in ‘‘oxide,’’ is not toxic. It is not a pollutant. It is not only natural,

it is indispensable for life on this planet.

What we need to understand is:

1. How does CO2 fit into the atmospheric mix? I’m told all CO2 is only 0.038 percent of atmospheric gases;

2. How does the CO2 from fossil fuel combustion fit into the total annual CO2 increase in the atmosphere? I’m told it’s only 0.4 percent of this amount.

3. How does U.S. fossil fuel consumption fit into mankind’s overall share of fossil

energy use? I’m told it’s 22 percent and shrinking; That means if we shut down 100

9

percent of all fossil fuel use in the United States, we would only reduce CO2 growth

in the atmosphere by 0.088 percent. That’s 0.0003 percent of the atmospheric gases,

and China will be filling in the gap, and then some.

4. How much will any legislation we consider actually change the total U.S. emissions and, in turn, change total human emissions and, in turn, effect global greenhouse gas concentrations?

In that real world context, we must ask: what legislation, if any, can we enact

this year that will plainly and significantly improve the health and lives of people

around the world a hundred years from now?

What will it cost? The people who will pay for our policy decisions are taxpayers

and consumers and workers. What amount is the right amount to take from them

and their families for our policies?

We also have to weigh what the opportunity cost might be in terms of other global

problems we neglect because of our huge economic and political investment in this

issue.

And we need to understand whether well-meaning steps to cap CO2 here and now

will simply drive industry offshore where control of actual pollution such as SOx,

NOx, mercury, and particulate is far more lax.

Whether we like it or not, CO2 correlates to national economic activity. That

means jobs, and the ability of working families to thrive is defined by jobs. Despite

impressive gains in energy intensity over the past few years, a basic reality is that

with the technology mix deployed today, to cap CO2 emissions restrains economic

output, jeopardizes economic growth, and eliminates people’s jobs.

Now there are three camps in the political discussion about capping CO2. One

camp doesn’t care. Its members are either indifferent or hostile to economic growth.

Some of them see the de-industrialization of the U.S. and they welcome it.

The opposite camp strongly favors economic growth and opportunity for America,

as well as for people around the world, and worries that this Congress could put

domestic growth and opportunity at risk.

The middle camp, however, is the most troubling. They’re the ones who want so

badly to believe we can easily and inexpensively innovate our way out of the linkage

between CO2 and economic vitality that they are willing to say, ‘‘Cap now, details

to follow.’’

That’s why we must study the science, the policy proposals, the costs, and the

benefits, and assess them all carefully. That is the path you, Chairman Boucher and

Chairman Dingell, have outlined for us.

I welcome our witnesses. Your views are critical for us to understand what the

state of science is. Please be clear with us, and don’t hesitate to separate the certainties from the uncertainties.

Thank you, Mr. Chairman.

Mr. BOUCHER.We are now pleased to welcome our panel of witnesses. I will say a brief word of introduction about each of them.

Dr. James Hurrell joins us from the National Center for Atmospheric Research in Boulder, CO, where he is a senior scientist and

the director of the Climate and Global Dynamics Division. He was

a contributing author to both the third and fourth assessment reports of the Intergovernmental Panel on Climate Change. He was

a lead author on the U.S. climate change science program’s synthesis and assessment product on temperature changes in the

lower atmosphere and he is currently serving on a National Research Council committee that is tasked to provide strategic advice.

Dr. Gabriele Hegerl joins us from Duke University where she is

a research professor at the Nicholas School of the Environmental

and Earth Sciences. She was a lead author in the IPCC’s third assessment report. For the fourth assessment report, she was a coordinating lead author for the chapter that focuses on determining

the causes of observed climate changes.

Dr. Michael Oppenheimer joins us from Princeton University

where he is the Albert G. Milbank professor of geosciences and

international affairs. He is affiliated with the Department of GeoVerDate 11-SEP-98 09:57 May 30, 2008 Jkt 000000 PO 00000 Frm 00014 Fmt 6633 Sfmt 6633 Q:\DOCS\110-14 SCOM1 PsN: SCOM1
10

sciences, the Woodrow Wilson School of Public and International

Affairs and the Princeton Environmental Institute. He was a lead

or contributing author to various chapters of the IPCC’s third assessment report and is a lead and contributing author to the fourth

assessment report.

Dr. Roni Avissar also joins us from Duke University where he is

the W.H. Gardner professor and chair of the Department of Civil

and Environmental Engineering. His research is focused on development and evaluation of various environmental fluid dynamics

models to study ocean, land, atmospheric interactions at the various spatial and temporal scales.

Dr. John Christy joins us from the University of Alabama in

Huntsville where he is a professor and director of the Earth Systems Science Center. He is also Alabama’s State climatologist. He

was a lead author of the IPCC’s third assessment report and is a

contributor to the fourth assessment report.

We welcome each of our witnesses. Your prepared written statements will be made a part of the record and we would be pleased

to receive your oral summaries of approximately 5 minutes.

Dr. Hurrell, we will be pleased to begin with you.

STATEMENT OF JAMES W. HURRELL, DIRECTOR, CLIMATE

AND GLOBAL DYNAMICS DIVISION, NATIONAL CENTER FOR

ATMOSPHERIC RESEARCH

Mr. HURRELL. Mr. Chairman, I thank you, Ranking Member

Hastert and the other members of the subcommittee for the opportunity to speak with you today on observed and likely future

changes in climate and the contribution from human activity to

those changes.

Although uncertainties continue to exist, significant advances in

the scientific understanding of climate change now make it clear,

as recently stated by the IPCC, that the warming of the climate

system is unequivocal and that this warming goes beyond the

range of natural variability.

The globe is warming dramatically compared with natural historical rates of change. Global surface temperatures today are more

than 1.4 degrees Fahrenheit warmer than at the beginning of the

20th century and rates of temperature rise are greatest in recent

decades. Eleven of the last 12 years rank among the 12 warmest

since 1850 and four of the warmest 5 years on record have occurred

since 2001. This past year, 2006, was the warmest on record over

the United States. There is a very high degree of confidence in

these numbers. Urban heat island effects, for instance, are real but

very local and they have been accounted for in the analyses. There

is no urban heat island effect over the oceans where the warming

has been very pronounced at both the surface and at depth. Moreover the ocean warming causes seawater to expand and thus contributes to global sea level rise of more than 1.3 inches since 1993

and 6.7 inches over the last century.

A key point is that an increasing number of many independent

observations give a consistent picture of a warming world. There

has been a widespread reduction in frost. There have been more

warm extremes and decreases are occurring in snow cover, Arctic

sea ice extent and thickness, and mountain glacier mass and exVerDate 11-SEP-98 09:57 May 30, 2008 Jkt 000000 PO 00000 Frm 00015 Fmt 6633 Sfmt 6633 Q:\DOCS\110-14 SCOM1 PsN: SCOM1
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tent. Increases in atmospheric water vapor content and resulting

heavier precipitation events, increased drought and increasing atmospheric temperatures above the surface are other signals of a

warming world.

Today’s best climate models are now able to reproduce these

major climate changes of the past century. Climate models are not

perfect and some models are better than others. Uncertainties arise

from shortcomings in our understanding of climate processes and

how best to represent them. Other forcings need to be more fully

considered such as historical and likely future changes in land use.

Yet in spite of these uncertainties, giving good replication to the

past, climate models are extremely useful tools for understanding

and determining the changes in forcing that are driving the observed warming.

Forcings imposed on the climate system can be natural in origin

such as changes in solar luminosity or volcanic eruptions or

human-induced such as the buildup of greenhouse gas concentrations in the atmosphere. These concentrations have increased

markedly as the result of human activities and they are now higher

than at any time in at least the last 650,000 years.

Climate model simulations that account for such changes in climate forcings have now shown that surface warming of recent decades is mainly a response to the increased concentrations of greenhouse gases and sulfate aerosols in the atmosphere. When the models are run without these forcing changes, the remaining natural

forcings and intrinsic natural variability fail to capture the almost

linear increase in global surface temperature over the past 25

years.

Moreover, observed increases in continental and ocean basin

scale temperatures as well as observed changes in precipitation

and other measures such as climate extremes are only stimulated

by models that include anthropogenic forcings. These simulations

have therefore convincingly shown that climate is changing in ways

that cannot be accounted for by natural variability or by changes

in natural forcings such as changes in the sun. Moreover this attribution of the recent climate change has direct implications for the

future. Because of the very long lifetime of carbon dioxide in the

atmosphere and the slow equilibration of the oceans, there is a substantial future commitment to further global climate change even

if concentrations of greenhouse gases in the atmosphere remain at

current levels.

In summary, the scientific understanding of climate change is

now sufficiently clear to show that climate change from global

warming is already upon us. Uncertainties do remain, especially

regarding how climate will change at regional and local scales, but

the climate is changing and the rate of change as projected exceeds

anything seen in nature in the past 10,000 years.

Thank you again for this opportunity to address the committee,

and I look forward to answering your questions.

[The prepared statement of Mr. Hurrell appears at the conclusion of the hearing.]

Mr. BOUCHER. Thank you, Dr. Hurrell.

Dr. Oppenheimer.

12

STATEMENT OF MICHAEL OPPENHEIMER, PROFESSOR, GEOSCIENCES AND INTERNATIONAL AFFAIRS, PRINCETON UNIVERSITY

Mr. OPPENHEIMER. Thank you, Mr. Chairman, and I would like

to thank the other members of this committee for this opportunity

to testify.

In addition to responding to the questions posed by the committee, my testimony addresses the subject of ice sheets and sea level

rise which received considerable attention in the wake of the publication of the IPCC report. Finally, I will report some recent findings from the peer-reviewed literature on the question of the time

remaining to avoid levels of climate change that some research has

characterized as dangerous.

I want to emphasize that I am testifying in my capacity as an

individual scientist and not a representative of IPCC or for that

matter Princeton University. The conclusions drawn here are my

own.

On the first question, are global temperatures increasing, IPCC’s

answer is unequivocal and I agree, global temperatures are certainly increasing. Furthermore, the warming and the associated

sea level rise have accelerated and a pervasive global climate

change is underway.

On the second question, to what extent is the increase attribute

to greenhouse gas emissions from human activity, here again I

fully support IPCC’s conclusion that it is very likely that most of

the recent climate change is attributable to human activities, particularly the emissions of greenhouse gases and aerosol particles.

Natural climate variability and changes in the sun and volcanic

emissions have played a much lesser role.

On the third question, how do we expect future global temperatures to be affected by greenhouse gas emissions, during this century global mean temperatures are likely to increase by amounts

that are larger and occur faster on a sustained basis than any in

the history of civilization and reach levels perhaps not seen in tens

of millions of years when ice sheets were much reduced and sea

level was much higher than today. The temperature change would

be largest on land and at high latitudes which includes large parts

of the United States. The climate change is expected to broadly affect key aspects of the climate system and simply put, would remake the face of the Earth.

I am particularly concerned about the fate of the great ice sheets

in Greenland and Antarctica. Because our ability to apply modern

numerical computer modeling techniques to ice is much weaker

than our ability to model the atmosphere, we must rely on other

information, particularly from climates of the past. IPCC notes that

sea level was likely 13 to 20 feet higher about 125,000 years ago

the last time Earth was about as warm as today, actually a little

bit warmer, mainly due to the retreat of polar ice when polar temperatures were 5 to 9 degrees Fahrenheit higher than at the

present. Additional global warming of only about 3 to 4 degrees

Fahrenheit may bring a return of such polar warmth. Accordingly,

and here I go beyond the remit of Working Group I of IPCC into

the general peer-reviewed literature, I conclude that a warming of

no more than 3 to 4 degrees Fahrenheit above present global mean

13

temperatures may represent a plausible objective for avoiding dangerous climate changes.

What does such a limit imply for actions to reduce emissions?

The answer is that the chances of avoiding such a warming appear

to be less than 50/50 if atmospheric concentrations of carbon dioxide are permitted to exceed 450 parts per million, noting that we

are currently around 380 parts per million. Unless the growth in

global emissions is reduced soon, first through reductions in emissions in developed countries like the United States, coordinated

with or followed closely by measures in developing countries, global

temperature is likely to eventually climb beyond the 3- to 4-degree

Fahrenheit limit. Then the ice sheets may gradually shrink, causing sea level to rise 13 to 20 feet, possibly over a period as brief

as several centuries but possibly over a millennium or more, and

if the warming were allowed to continue, that would be only the

beginning of a processes that may eventually lead to total loss of

both the Greenland and the West Antarctic section of the Antarctic

ice sheets and a much larger sea level rise.

Only prompt and sizable reductions in global emissions, hopefully carried out with the leadership of the United States and in

collaboration with other large emitting countries such as the EU,

Japan, China and India would avoid such an eventuality. I point

to the 5-, 10- and 15-year mandatory emissions reduction targets

embodied in the proposal from USCAP as plausible initial steps to

meet this challenge.

It is apparent to me and I hope to everyone else that the U.S.

and all other countries ought to prepare to deal with a warmer

world in any event. It is even more important to note that the window of opportunity to avoid potentially dangerous climate outcomes

may be closing fast.

Thank you.

[The prepared statement of Mr. Oppenheimer appears at the conclusion of the hearing.]

Mr. BOUCHER. Thank you, Dr. Oppenheimer.

Dr. Hegerl.

STATEMENT OF GABRIELE HEGERL, ASSOCIATE RESEARCH

PROFESSOR, EARTH AND OCEAN SCIENCES DIVISION, DUKE

UNIVERSITY

Ms. HEGERL. Thank you, Mr. Chairman, and thank you, members of the committee, for giving me the opportunity to testify

today about global warming.

To address your questions, I would like to draw your attention

to some slides. May I see the first slide, please?

[Slide shown.]

This slide shows you that evidence for warming in the climate

system is widespread. The top left panel shows you the observed

warming over the 20th century from the surface temperature

record, the top right panel, the observed warming from atmospheric

temperatures and the bottom shows you warming from the ocean

temperature measurements. This widespread nature of the warming and the way it is consistent between different components of

the climate system led us to the conclusion that warming of the climate system is unequivocal. Furthermore, the pattern of warming

14

being quite uniform, the warming in each individual component of

the climate system being much larger than we expect due to natural climate variability such as El Nin ̃ o led us to the conclusion that

it is extremely unlikely that such a warming in all major components of the climate systems would occur without external forcing,

and we also concluded that it is very unlikely due to natural causes

alone.

Can I see the second slide, please?

[Slide shown.]

Climate models incorporate our best understanding of how the

climate system works and driven with observed changes in radiative force such as changes in greenhouse gases, aerosols, volcanic

and solar forcing reproduce the 20th century temperature record

quite well. What you see at the top right panel model simulations

from a large number of modeling centers and from a large number

of models, some of them including smaller forcings like land use

change, differing in details of forcing and model physics. The observed warming shown in black lies quite well within the model

framework. You can also see that the climate models respond similarly the observations to individual events like volcanic eruptions

shown by the gray bars—you can see the records go down a little

bit in response to that—and at the bottom panel you see that if

driven with natural forcings only such as solar and volcanic forcing, climate models can not reproduce the 20th century warming.

To conclude, however, what caused the 20th century warming,

we resort to quite different methods. We do not resort to modeling

alone but we try to estimate the effect of the different external influences such as greenhouse gases from the observed change so we

look for fingerprints of warming as we expect due to increases in

greenhouse gases or other forcings based on these sophisticated

studies which focus on the observations allow for the possibility

that the response to a forcing could be larger or smaller than anticipated in models, that it could be somewhat different in pattern

and it could be not present at all. Carefully investigating alternative physical explanations for the observed warming, we came to

the conclusion that it is very likely that most of the observed

warming was caused by the greenhouse gas increase. This conservatively accounts for the remaining uncertainty of which we are

quite aware.

Can I see briefly the next slide, please?

[Slide shown.]

We can also draw this type of analysis now based on space and

time patterns of warming on individual continents, concluding for

example that North America is quite outside the range of where we

would be due to natural variability alone at this point in time.

Can we move one slide on, please?

[Slide shown.]

The last slide shows you the predicted future warming in the

context of the 20th century simulated warming based on observed

records of warming from the 20th century from cooling in the last

glacial maximum. From various studies we can conclude that the

sensitivity of the system to external forcing is not small. Climate

responds substantially to changes in radiative forcings such as

changes in greenhouse gases. Based on this, we concluded that it

15

is very unlikely that climate sensitivity is less than one and a half,

pretty much ruling out various model responses of the climate system in the future and future warming depends on the emissions

scenarios we take on and ranks from one and a half to nine times

the observed warming over the 20th century.

[The prepared statement of Ms. Hegerl appears at the conclusion

of the hearing.]

Mr. BOUCHER. Thank you, Dr. Hegerl.

Dr. Avissar.

STATEMENT OF RONI AVISSAR, PROFESSOR AND CHAIR, DEPARTMENT OF CIVIL AND ENVIRONMENTAL ENGINEERING,

DUKE UNIVERSITY

Mr. AVISSAR. Thank you, Mr. Chairman and members of the

committee.

May I have the slides, please? The next one.

[Slide shown.]

The point that I would like to make here as an introduction first

of all is that I am not disputing the results or most of the results

of IPCC and of my colleagues. In other words, the climate seems

to be indicating an increase of the temperature over the past years

and IPCC has very eloquently reported on all the studies that demonstrate that. The questions that have been asked in front of us,

are global temperatures increasing, I would answer based on the

report of IPCC, yes.

The second question, if global temperature increasing, to what

extent is the increase attributed to greenhouse gases emission from

human activity is where I start having slightly different opinion

and so the question, how do we expect the future global temperature to be affected by greenhouse gases. I believe that in spite of

the fact that the models are an essential tool to be able to evaluate

the climate and are probably the only good tool that we can have

to speculate about what is going to happen in the future climate,

there are still a lot of uncertainties in these models, and because

of those uncertainties and the way that they are built, we have difficulty to estimate exactly what is the proportion of the greenhouse

gas contribution to the overall climate versus many other activities

that are taking place from the human activity.

On this report of IPCC, I guess that the lower bar that indicates

the overall contribution of the human activity indicates an overall

contribution with a lot of uncertainty and then the proportion of

the different components is where maybe we need to look at a little

bit more carefully. In order to do that, I am going to use just a simple representation of land cover change and demonstrate to you

how in fact the models that we are using to make these assessments can be mistaken. If I can have the next slide, please?

[Slide shown.]

What you see here is a scenario of deforestation of the Amazon

basin, in part due to the intention of investing much more in

biofuels as a replacement maybe to traditional oil, and this is a scenario that was produced based on socioeconomic development for

2050, so about 50 years down the road. And you can see here that

most of the basin is going to be deforested to be replaced with agriculture areas and other areas. Next slide, please.

16

[Slide shown.]

The study that we have conducted with models that are better

designed to look into those particular processes, higher resolution

models, indicates present results that are slightly different than

what the global climate models are providing, and what you see

here is a sequence of precipitation for the past 30 years—that is

the upper graph—that shows that over the past 4 years we had as

sequence of high precipitation and then in 1998 a very low precipitation in the Amazon basin, that is showing an El Nin ̃ o year, and

then 2 years that were somewhat close to the average precipitation.

When we use this sequence of precipitation and we feed with the

meteorology that has been observed over the area, those mesoscale

models, and we combine that with the land cover change, we see

the sheet of precipitation that you have on the lower left figure. In

other words, what you notice there is that there are areas that receive much less precipitation and in fact the areas that are mostly

deforested receive much more precipitation than what was originally obtained.

When you combine all those results and you look at the impact

that that has with the global climate models that are currently

used versus the original models, you can notice especially, you look

the lower right curve, you can notice that in fact the global climate

models just for that particular phenomena indicates a difference of

precipitation that is twice more severe than what you would get

with a model that is better capable of representing the clouds and

radiation system. Next picture, please.

[Slide shown.]

All right. The point that we were asked to answer is what do we

think is the next direction for research. I guess that I would like

to advocate here for better models, and in particular, models that

are capable of representing much better the cloud radiation feedback, the models that are capable of representing the biosphere

and the hydrosphere a little better and models that can account for

process that are extremely significant on the climate system like

aerosols, fires and all kinds of other processes that are significant.

So I think that the scientific community is going that direction.

I think that we may get some surprises from these models when

we can combine all the human activities that we have.

Thank you.

[The prepared statement of Mr. Avissar appears at the conclusion of the hearing.]

Mr. BOUCHER. Thank you, Dr. Avissar.

Dr. Christy.

Mr. BARTON. Mr. Chairman, we have bits and pieces of what the

witness just showed us but we don’t have it in the coherent form.

Could we get him to give that to us?

Mr. BOUCHER. Dr. Avissar, would it be possible for you to reproduce your slides as prints and provide those to the committee.

Mr. AVISSAR. Sure.

Mr. BOUCHER. Thank you, Mr. Chairman, and we will share

them with you.

Dr. Christy.

17

STATEMENT OF JOHN R. CHRISTY, PROFESSOR AND DIRECTOR, EARTH SYSTEM SCIENCE CENTER, NSSTC, UNIVERSITY

OF ALABAMA IN HUNTSVILLE

Mr. CHRISTY. Chairman Boucher, Ranking Member Hastert and

committee members, I am John Christy, director of the Earth Systems Science Center at the University of Alabama in Huntsville.

I lead a group which builds climate data sets from scratch with

interesting results. For example, in constructing surface temperatures in California’s Central Valley, we found a dramatic rise in

nighttime temperatures that did not occur nearby in the Sierras.

This points to a human fingerprint on climate change likely being

the massive conversion of dry land to irrigated agriculture and urbanization but not greenhouse gases. In these and other data sets,

we find inconsistencies between observations and the output of climate models which tried to tell us the climate effect of greenhouse

gases.

Now, I go into detail in my written remarks to answer your questions on temperature changes. Yes, the surface temperature is rising, an unknown portion of which I believe is due to extra greenhouse gases, and the current rate of about 0.15 degrees Celsius per

decade is a sensible projection.

Now, the implication of these questions, however, leads me to

discuss both climate and energy use. In 1900, the global energy

technology supported 56 billion human life-years and that is 35-

year life expectancy times 1.6 billion people. It is an index. Today

energy technology supports 426 billion human life-years, an eightfold increase, and some of these human life-years are mine. I have

been allowed to become a grandparent, a situation that is now the

rule, not the exception. An eightfold increase in the global experience of human life, that is a spectacular achievement delivered by

affordable energy. It disturbs me when I hear that energy and its

byproduct, CO2, are being demonized when in fact they represent

our greatest achievement. Where there is no energy, life is brutal

and short. When you think about the extra CO2 in the air, think

also about the eightfold increase in human life.

While preparing this testimony, I was reminded of my missionary experience in Africa. African women collect firewood each day

and carry it home for heating and cooking. This inefficient and

toxic source of energy kills about 1.6 million women and children

a year. When an African woman carrying 50 pounds of firewood

risks her life by jumping out in front of my van in an attempt to

stop me to give her a lift, I see the value of energy. You see, what

I had in my school van in terms of the amount of gasoline I could

held in my cupped hands could move her and her firewood 2 or 3

miles down the road to her home. I understood the astounding benefit energy represents and to what extent she and her people would

go to acquire it. Energy demand will grow because it makes life

less brutal and less short.

The continuing struggle of the European Union and other countries to achieve their self-imposed Kyoto targets, indeed falling behind the U.S. in slowing emissions growth, implies a lot of things

but two that stand out to me are, one, underestimating people’s demand for energy, and two, overlooking the well-known tendency for

18

countries and industries to game the system for their own benefits

without really producing any real emission reduction.

This body is being encouraged to ‘‘do something’’ about global

warming and the dilemma begins with this: energy demand will

grow because its benefits are ubiquitous and innumerable. The dilemma then is, how can emissions be reduced in a way that doesn’t

raise energy costs, especially for the many poor people in my State

and the world.

There are several new initiatives on energy reductions being proposed as a benchmark. Those which are in the ballpark of the

Kyoto-like reductions will produce a small impact on emissions and

thus a very, very small impact on whatever the climate does. I

have written a number of papers about the precision of our climate

records. The impact of Kyoto-style reductions will be too small for

we scientists to measure due to the natural variations of climate

and the lack of precision in our observing system. In other words,

we will not be able to tell lawmakers with any confidence that specific regulations achieve anything in terms of ‘‘climate control’’ in

this country or the world. And when you think about it, the climate

system is so complicated, we really can’t tweak it for a predictable

outcome.

So let me close with this observation from my scientific research

and life experience. Helping people develop economically is the fastest route I see to giving them the tools they need to adapt to whatever the climate does including that portion of change that may be

due to human influences.

Thank you.

[The prepared statement of Mr. Christy appears at the conclusion of the hearing.]

Mr. BOUCHER. Thank you very much, Dr. Christy, and thank you

to each of the members of our panel for providing information to

us this morning. We have approximately 5 minutes before we must

recess the committee for the joint session on the floor. I will take

that opportunity to ask my set of questions to this panel.

Mr. BARTON. Mr. Chairman, a parliamentary inquiry?

Mr. BOUCHER. Sure.

Mr. BARTON. What would it take to continue this hearing while

the joint session is underway? Would a unanimous consent request

allow us to continue, or is it impossible?

Mr. BOUCHER. Mr. Barton, we examined that and I share your

desire to continue this hearing. Unfortunately, it is a rule of the

House and it is not waivable by our unanimous consent request.

Mr. BARTON. So there is no way?

Mr. BOUCHER. I am afraid there is no way.

Mr. BARTON. Thank you, Mr. Chairman.

Mr. BOUCHER. But thank you for asking.

I would like to get a better sense of where our expert witnesses

agree and so let me ask each of you if you would to respond to this

group of questions, and for purposes of brevity, a simple yes or a

no would be desirable by way of response.

First question: In the executive summary that was released in

February, the IPCC found that—and I quote from the report—

‘‘Most of the observed increase in global averaged temperatures

since the mid–20th century is very likely due to the observed inVerDate 11-SEP-98 09:57 May 30, 2008 Jkt 000000 PO 00000 Frm 00023 Fmt 6633 Sfmt 6633 Q:\DOCS\110-14 SCOM1 PsN: SCOM1
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crease in anthropogenic greenhouse gas concentrations,’’ in other

words, those concentrations that came from human activity.

Do you agree or disagree with that conclusion, Dr. Hurrell?

Mr. HURRELL. Yes, I do agree with that conclusion.

Mr. BOUCHER. Dr. Oppenheimer?

Mr. OPPENHEIMER. I agree.

Mr. BOUCHER. Dr. Hegerl?

Mr. HEGERL. I agree. My chapter proposed that conclusion.

Mr. BOUCHER. Dr. Avissar?

Mr. AVISSAR. I cannot answer by yes or no. I would say that I

tend to agree, but I am not convinced.

Mr. BOUCHER. OK. So you lean in favor of that finding?

Mr. AVISSAR. I am sure that there is a contribution from the

greenhouse gases. I have no doubt about that.

Mr. BOUCHER. That is good. Thank you, sir.

Dr. Christy?

Mr. CHRISTY. A similar answer, the contribution from greenhouse

gases, but I don’t know how much.

Mr. BOUCHER. All right. I would note that the IPCC defines ‘‘very

likely,’’ which is the language used here, as a 9 in 10 chance that

the finding is accurate.

Question No. 2: The IPCC also found that—and again I quote

from the report—‘‘Continued greenhouse gas emissions at or above

current rates would cause further warming and induce many

changes in the global climate system during the 21st century that

would very likely be larger than those that were observed during

the 20th century.’’ Do you agree or disagree, Dr. Hurrell?

Mr. HURRELL. Yes, I do agree with that.

Mr. BOUCHER. Dr. Oppenheimer?

Mr. OPPENHEIMER. I agree.

Mr. BOUCHER. Dr. Hegerl?

Mr. HEGERL. I agree.

Mr. BOUCHER. Dr. Avissar?

Mr. AVISSAR. Not enough information to answer.

Mr. BOUCHER. All right.

Dr. Christy?

Mr. CHRISTY. I think since we are starting at a warm spot that

the changes will continue.

Mr. BOUCHER. All right. Thank you.

Now, one additional question that I will ask and I will ask for

a little bit of comment from you on this one. Dr. Avissar has testified that regional climate models could be improved by incorporating the effects of land use in the area for which that regional modeling is being performed. Assuming that you agree with Dr.

Avissar, do uncertainties about land use effects or other regional

uncertainties diminish either our understanding of how greenhouse

gases affect global warming or the justification for reducing greenhouse gases? And I would ask you not only do you agree but why

or why not.

Dr. Hurrell?

Mr. HURRELL. Thank you. Yes, I do agree with Dr. Avissar’s testimony on this point. As several of us have pointed out, global climate models are very valuable tools. They are not perfect and they

can certainly benefit, as I pointed out explicitly, from further and

20

more complete considerations of, for instance, land surface change

and land surface forcing. Regional models are one avenue to begin

to include those processes more completely and the field is moving

in that direction. With respect to your bottom-line statement, Mr.

Boucher, I believe that the global climate models indeed given their

very impressive simulations of the observed hemispheric scale and

larger-scale temperatures, that is evidence that many of the key

processes are indeed correct in the large-scale models and therefore

I believe that the evidence is very convincing that the range of

changes that we have seen goes beyond the range of natural variability and can be attributed to anthropogenic influence on largescale climate but certainly regional processes do need to be included better. As we begin to try to make comments on regional

and local scale changes, the role of natural variability becomes

larger and there are uncertainties in our understanding at that

level.

Mr. BOUCHER. Thank you very much.

Dr. Oppenheimer?

Mr. OPPENHEIMER. I would generally agree with Dr. Avissar and

I would add, by the way, that we need to improve our ability to

model the ice sheets and that is a critical component to understanding sea level rise. I have substantial amount of confidence in

the statements about the importance of the greenhouse gases, the

projection of future climate and the attribution of recent climate

changes, not only because of the global models and their ability to

reproduce past climate changes of, say, the last 150 years but also

because of the wealth of paleoclimate data, that is, data on climate

history, which basically supports general conclusions from the atmosphere, ocean general circulation models.

Mr. BOUCHER. Thank you, sir.

Dr. Hegerl?

Mr. HEGERL. I agree with Dr. Avissar’s testimony that it is very

important for regional predictions, for reliable regional predictions

to think about land-use change and incorporated also for reliable

predictions of rainfall changes. I do not think that these changes

have a big impact on large-scale temperature predictions nor do

they affect our assessment of what caused the 20th century warming.

Mr. BOUCHER. Thank you.

And Dr. Avissar, let me just modify the question for your purposes. I think we are all acknowledging, your colleagues are, that

there are uncertainties about the accuracy of regional models based

upon particular land uses in the area which are not properly incorporated into those models but the real question is, does that uncertainty affect our understanding of climate change on a global basis,

and should that uncertainty about the regional modeling in any

way affect our decision-making about whether it is proper to go forward or not with any kind of control measures?

Mr. AVISSAR. And I appreciate that. The point that I want to

raise here is that I am using the land cover, the original scale, just

as an example to illustrate what is happening. The truth is that

the complexity of the climate system and it is a chaotic system and

we do not know exactly how it is going to evolve. We use that with

models that are idealized. There are a lot of problems in those modVerDate 11-SEP-98 09:57 May 30, 2008 Jkt 000000 PO 00000 Frm 00025 Fmt 6633 Sfmt 6633 Q:\DOCS\110-14 SCOM1 PsN: SCOM1
21

els. The type of interactions that we are talking about that have

to do with the land cover but with many other processes and it is

probably one of the most severe ones.

Mr. BOUCHER. Thank you, Dr. Avissar. I am afraid time will not

permit any further explanation but we understand your response.

Dr. Christy?

Mr. CHRISTY. We have rebuilt data sets in three parts of the

world very carefully. Climate models don’t come close to what actual observations have shown so I have a bit of a disagreement

with the notion that even though climate models get some big number right that they don’t get the smaller regions right. So I do

agree with Dr. Avissar’s point that the regional expectations of current models—or regionalization is a way to improve these global

climate models.

Mr. BOUCHER. Thank you very much. My time has more than expired.

The joint session, I assume is underway, although I do not see

bells having rung. Do we have any information about that? It was

supposed to convene at 11:00.

Mr. BARTON. I am ready to keep going.

Mr. BOUCHER. I am ready to keep going too but I think we have

to observe the rule.

Mr. BARTON. I won’t tell.

Mr. BOUCHER. Why don’t we say——

Mr. BARTON. It has not started, my staff says.

Mr. BOUCHER. It has not started?

Mr. BARTON. No, sir.

Mr. BOUCHER. I think the best course for us at this point is in

fact to recess, and my apologies to our witnesses for this. I hope

your patience will enable you to remain here and answer additional

questions my colleagues will propound. Let us reconvene 5 minutes

after the joint session has concluded. The subcommittee stands in

recess.

[Recess.]

Mr. BUTTERFIELD [presiding]. Come back to order.

I was not in the session this morning. I understand that the witnesses have already testified and we have started the questions.

Have we done the opening statements? We have done the opening

statements.

Let me thank all of you for your patience. This has been a disjointed morning this morning. I am sure you have been informed

that we had a special session of Congress this morning at 11:00

and we have just completed that and now we are back to work.

At this time the Chair will recognize the distinguished gentleman from Illinois, Mr. Hastert.

Mr. HASTERT. Thank you, Mr. Butterfield. I appreciate that, and

again, I appreciate all the patience of our people who are witnesses

who are here to testify today.

Mr. Oppenheimer, in your statement you were talking about the

polar ice fields, specifically in Antarctica, and talking about the

thickness of the sheets and the possibility of I think it is 1,000

years that they may melt. Hasn’t the temperature actually in the

South Pole not been affected?

22

Mr. OPPENHEIMER. We really don’t have a good picture of what

temperatures have done over the last 100 years for the continent

as a whole. We know that temperatures have warmed on the Antarctic peninsula which is the furthest north point and we know

that the limited number of stations, and I think it is really only

two inland away from the coast did cool for some period of time.

There is some indication that that trend is reversing. So my own

judgment on that, and there is not complete agreement on this in

the community, is that we cannot make a statement about what

the Antarctic continent as a whole has done over the past century.

There simply isn’t enough data.

Mr. HASTERT. Then if we are talking about the ice fields at the

South Pole and Antarctic, we need to be careful about what we say.

Mr. OPPENHEIMER. We need to be careful about how we represent what has happened in the past. There is no question about

that.

Mr. HASTERT. And what happened in part is hard to have the

prognosis. It almost has to happen in the future.

Mr. OPPENHEIMER. We have some idea of what happened in the

very distant past, not a very firm idea, and we have a better idea

of what happened in the distant past for Greenland. So would you

like me to elaborate?

Mr. HASTERT. Well, I am short on time here so I appreciate your

answer.

Dr. Christy, in your report and your testimony about land use

and agriculture changes in the Central Valley of California, that

they had an impact on temperature and that you are starting to

see this in other work. When we hear about rising temperatures

and other climate changes, should we keep in mind that that land

use may play a more significant role than we have talked about?

I come from the Midwest, an agricultural district, and in April

when the fields are plowed and you are ready to plant corn and

soybeans, everything is black. Heat is absorbed by that black loam

and then of course and by the end of May, and the first part of

June, it is covered in green. It changes. What is the effect?

Mr. CHRISTY. Well, as a graduate of the University of Illinois, I

have seen those same fields, and what we found at least in the

study we have done in California and also now in Africa that you

alluded to is that that is explaining the largest changes that are

occurring there, that it is not something that can be affected by

greenhouse gases. It is something that the way in which the warming occurs. It is related to what humans are doing to the landscape,

not to the atmosphere.

Mr. HASTERT. Dr. Avissar, again, another phenomenon that exists are clouds. some clouds have a cooling effect, some clouds have

a heating effect. They hold heat in. Can you explain how clouds are

treated in the models and are they approximated and we can trust

the many approximations of real process and models to faithfully

simulate the real world over decades?

Mr. AVISSAR. Our understanding of the cloud system is still relatively limited, OK. We have some moderate understanding of the

way that the models of the way that the clouds are behaving and

we are using that understanding to put that into our models so I

23

would say that the best in our models we have a moderate capability of representing the cloud system. It is done not very well.

Mr. HASTERT. Dr. Christy, the average daily temperatures, you

suggest in your testimony, are more reliable measures of the effects

of greenhouse gases in the atmosphere. What do these findings

suggest about the relative role of carbon dioxide and climate

change if the research holds up?

Mr. CHRISTY. OK. The point here is that the temperature that occurs at the maximum warming in the afternoon is more closely related to the deep atmosphere and therefore to what greenhouse

gases are doing to the atmosphere and those trends are less than

what you see in surface temperature maps, for example, that were

shown earlier. So that indicates that if that is the signal of what

greenhouse gases are doing in the atmosphere that that is a smaller signal than we have been led to believe at this point.

Mr. HASTERT. Thank you. My time has expired.

Mr. BUTTERFIELD. The gentleman’s time has expired.

Let me just again thank each one of you for coming today. We

are going to be completing this hearing this afternoon and hopefully all of the Members will come through and have an opportunity to ask their questions.

But let me direct my question very briefly to Dr. Hurrell. Dr.

Hurrell, as many of the members of this committee can attest, we

have been around for a long time including the decade of the 1970’s

and during that period of time we were given many warnings,

many pessimistic warnings that the planet was cooling. That was

the advice that was given to us by scientists during that era, and

then they ask why given how wrong the scientists were back then,

at least some of the scientists were back then, why we should trust

the scientists now when we talk about global warming. How do we

explain that the science is now different than it was in the 1970’s?

Mr. HURRELL. Thank you very much. There were a handful of

scientists who were taking about a global cooling signal and potential causes for that. A key aspect of this is that the climate system

does vary and it varies for both natural as well as anthropogenic

reasons. The fundamental difference now is that unlike in the mid–

1970’s when a few scientists were talking about this, we are talking about much stronger evidence now, much better understanding

and an entire climate community or almost an entire climate community who is in agreement on the major points. There have been

the IPCC assessments. There has been National Academy of

Science reports. There has been U.S. Climate Change science program results and the like that all speak to these general conclusions that we are talking about today. This is quite different from

the situation in the 1970’s where there simply was not nearly as

comprehensive and expensive look at what could have been causing

that bit of global cooling that we saw really from a peak in the

mid–1940’s into the mid–1970’s.

Mr. BUTTERFIELD. We have just been joined by the gentleman

from California, Mr. Waxman, and he has informed the Chair that

he is going to have to leave very shortly and so I am going to yield

the balance of my time with the unanimous consent of the other

side to Mr. Waxman, in addition to his time.

24

Mr. WAXMAN. Thank you very much, Mr. Chairman, and I hope

you will reclaim your time later because I know you are being very

kind to me in letting me go forward here.

At several of the hearings, some Members have wondered how

important human-caused greenhouse gas emissions are when there

are even larger amounts of naturally occurring greenhouse gas

emissions each year.

Dr. Hurrell, can you help us understand this? Can you explain

why human-caused emissions are so important even though every

year there is a greater volume of naturally occurring emissions?

Mr. HURRELL. Absolutely. Thank you. Yes, there is a large volume of naturally occurring carbon dioxide emissions by natural

processes in the climate system. These have occurred of course

throughout time. The key way to think of this problem I believe is

that the natural system has both sources and sinks and it maintains a balance in terms of the natural system. Therefore, even

though the human contribution in terms of a percentage might be

relatively small to the total amount of carbon dioxide in the atmosphere, it is very significant because it is upsetting this natural balance. It is basically throwing the system out of whack and so it

provides a very important radiative forcing on the climate system

that the climate system must adjust to and it does that by way of

warming, among other changes.

Mr. WAXMAN. Dr. Oppenheimer, from what I heard from Dr.

Christy, he seems to be saying—and correct me if I am wrong—

that this latest report from the Intergovernmental Panel on Climate Change diminishes some of the reasons to be concerned about

the impacts of climate change. For example, he stated reductions

in the scariest realization of sea level rises are welcomed. I am concerned about the accuracy or your views of that position.

Mr. OPPENHEIMER. What IPCC did in this report is to narrow the

range of uncertainty on future sea level rise so that the lowest projection of possible sea level rise has been raised and the projection

of highest plausible sea level rise within 90 percent confidence has

been lowered. On the other hand, IPCC was very careful to note

that its projections do not account fully for processes that we know

are going on in Earth’s ice sheet in Greenland or in West Antarctic

and so those projections have to be regarded themselves as relatively cautious because they assume the ice sheet will not continue to accelerate their loss of ice into the sea, which increases sea

level.

Mr. WAXMAN. It is my understanding the IPCC’s sea level rise

projection only includes the melting of glaciers and the increased

volume of the oceans due to the absorption of greater warmth. Is

that correct?

Mr. OPPENHEIMER. Not quite. There is an attempt to account for

the fact that over the last decade ice in both Greenland and parts

of Antarctic have started to move very rapidly into the sea. Those

are called dynamical changes because they are flows like rivers

flow. The ice flows like rivers in certain spots. The IPCC added to

its melt this approximation to sea level rise that you get from just

looking at melting a small amount to account for these extra flows

that are occurring in the rivers of ice coming off the continents but

it did not make any estimate for what could happen if those flows

25

increase in the future and there is a significant risk that those

rates of ice flow will in fact increase.

Mr. BUTTERFIELD. Let me ask you to suspend for just a minute,

please. The gentleman’s time has expired, and with the unanimous

consent of the minority, I would ask that Mr. Waxman be allowed

to continue with his regular time.

Mr. BARTON. Point of parliamentary inquiry.

Mr. BUTTERFIELD. Yes, sir.

Mr. BARTON. I am not going to object. I know people are busy,

but would this mean Mr. Waxman would get 5 minutes and then

we would get 5 minutes for our side.

Mr. BUTTERFIELD. The gentleman had 8 minutes because he did

not exercise his right to an opening, so it is 3 plus 5.

Mr. BARTON. Three plus 5 or 3 plus 8?

Mr. BUTTERFIELD. Three plus 5. Yes. The gentleman requests 5

minutes. All right. The gentleman is recognized for 5 minutes.

Mr. OPPENHEIMER. So my point is that in one sense the IPCC

projections are regarded by many scientists as conservative because

they are unable to account for the accelerated loss of ice into the

sea that we know is occurring. We don’t have a model that can tell

us how to project those sorts of changes. The best we can do is look

at what happened in past climates a long time ago when the poles

were somewhat warmer than today and see what the fate of the

ice was. What we know is, the Greenland ice sheet was significantly smaller and sea level was 4 to 6 meters higher, about 13 to

20 feet. We don’t know how fast that occurred. We don’t know

whether that process has already been triggered in fact.

Mr. WAXMAN. So in your view, you don’t see any reason that this

most recent IPCC report should make us less concerned about the

impacts of climate change than we previously believed?

Mr. OPPENHEIMER. Overall, it makes me more concerned, and the

things that are quite uncertain in the report make me concerned

because they are uncertain and they could wind up either turning

out smaller or they could turn into very, very big hazards in the

future.

Mr. WAXMAN. Dr. Christy, in your testimony you also discuss

some new proposals to control greenhouse gas emissions that are

in the ‘‘ballpark of the Kyoto-like reductions.’’ You state that these

proposals would have a very small and perhaps undetectable impact on preventing climate change. One of the industry’s strongest

criticism of the Kyoto protocol was that it wouldn’t solve the problem. Under the Kyoto protocol, the developed world would take one

step toward emissions reductions by 2012. However, these reductions alone were not enough to solve the problem and of course industry was concerned about what unknown targets they might face

after 2012. When you include the lack of targets for the developing

world, I can see why you would say it is hard to predict the climate

outcomes associated with Kyoto. Fortunately, we have moved beyond the Kyoto debate.

I have a chart that shows the emissions targets for the greenhouse gas reduction bills that have been introduced in the 109th

and 110th Congresses. Would you say that any of these bills are

in the ballpark of the Kyoto-like reductions?

[The chart follows:]

26

27

Mr. CHRISTY. This is just for the United States, right?

Mr. WAXMAN. Yes, bills introduced in the Congress here.

Mr. CHRISTY. I don’t know if I can understand the question.

Kyoto is the red and it looks like two and three intend to go beyond

Kyoto out to 2030 or 2040. I mean, I am just reading the chart.

Mr. WAXMAN. Right.

Mr. CHRISTY. But I think my point would still be the same, is

that since this is only the United States, that our ability and our

observing system is not capable of saying here is a change that we

can confidently attribute to one of these bills.

Mr. WAXMAN. At least five of the bills introduced are not Kyotolike. Let us assume that the U.S. commits to emissions cuts in the

range called for by these five bills and let us assume that on this

basis the U.S. positions itself as a world leader and convinces other

nations to undertake similar emissions cuts.

Dr. Hurrell, do you agree that this range of emission cuts on this

time frame will have a measurable effect on the climate?

Mr. HURRELL. I personally believe it is essential that these kind

of trajectories are adopted. I believe that while there are uncertainties in our knowledge, as we have already discussed widely today,

we know quite a bit and I think that the potential consequences

of global climate change are important enough that these kind of

reduction proposals should be adopted. I agree with your statement

that the United States can play a leadership position in convincing

the rest of the world to go along. It has to be a global solution. It

can’t be something that we do alone.

Mr. WAXMAN. Dr. Hegerl, based on your expertise on climate

forcing, would emission cuts in the range of 65 to 80 percent over

the next 45 years have a measurable effect on the climate?

Ms. HEGERL. Can I have the last figure of my testimony, please?

Mr. WAXMAN. Sixty-five to 80 percent over the next——

Ms. HEGERL. Oh, no, the last figure of my figures, please. Next

one. So what you see here is in yellow is the lowest limit of what

we can do physically. This is if we would freeze concentrations at

the present time and what you see in colors are the various emissions. So any bill that would reduce emissions beyond the lowest

emission there will have a big impact on future global temperature

rise and with it on the impact global warming can make quite a

bit of difference because impacts are expected to correlate somewhat with the global mean temperature increase.

Mr. BUTTERFIELD. The gentleman’s time has expired.

Mr. WAXMAN. Mr. Oppenheimer, do you have anything on that

as I ask my last question?

Mr. OPPENHEIMER. Yes, I agree, it would have an effect, particularly since the U.S. taking leadership I think would bring other

countries along and then we would have a serious global reduction.

Mr. WAXMAN. Thank you.

Thank you, Mr. Chairman.

Mr. BUTTERFIELD. The gentleman’s time has expired.

The gentleman from Texas, the ranking member of the full committee, is recognized for 5 minutes.

Mr. BARTON. Mr. Chairman, before I use my time, I would ask

Dr. Hegerl or Dr. Oppenheimer to provide us with a copy of the actual report. They keep referring to it. All we have is the summary

28

and this is the 2001 report. What we have is about a 10-page summary. They have seen it; we haven’t. I think we need the report

and have it in the record of this hearing or at least have it available for members of the subcommittee.

Mr. OPPENHEIMER. Could I comment on that? I have been careful

in my testimony to refer only to what is in the summary because

the actual details are not going to be available until May. I wish

they were available today but I don’t——

Mr. BARTON. Well, your testimony was so specific, you are bound

to have seen the report. There is no way you could say some of the

things you have said if you haven’t seen the report.

Ms. HEGERL. The U.S. Government has commented extensively

on the draft report so it has seen the draft reports and——

Mr. BARTON. Well, we are part of the U.S. Government and

we——

Ms. HEGERL. Yes, so you could——

Mr. BUTTERFIELD. Point of order. Will you make the report available when it is available?

Mr. OPPENHEIMER. Certainly.

Mr. BARTON. It is something available now, Mr. Chairman.

Mr. BUTTERFIELD. When do you estimate that to be?

Mr. OPPENHEIMER. It will be published publicly in May. I don’t

have the power or the authority to release the report.

Mr. BARTON. But you have read it.

Mr. OPPENHEIMER. I have read it but I have been—first of all,

it may change in some respects between now and May. Second of

all, I have been extremely careful, as I think these people have

been too, to refer only to items which can be defended by looking

at the summary, which is public. Do you want me to go over that

point by point? I would be happy to.

Mr. BARTON. Mr. Chairman, were based on more than this summary. I have read the summary.

Mr. BUTTERFIELD. Let me ask the gentleman to suspend. This

has extended beyond a parliamentary inquiry. I am going to recognize the ranking member for 5 minutes.

Mr. BARTON. Well, I want some definition about how we are

going to get a copy of this report.

Mr. BUTTERFIELD. Well, the gentleman has said it is not available and he will make it available when——

Mr. BARTON. Well, if it available to those people and it has been

available to parts of the executive branch, it should be available to

members of this subcommittee under some conditions that are acceptable to both the majority and the minority. I am not saying we

are going to publish it but I think we ought to have it available.

That is the whole purpose of this hearing.

Mr. BUTTERFIELD. From the majority side, if the report is available, we will certainly accept it and make it available.

Mr. MARKEY. Will the chairman yield briefly?

Mr. BUTTERFIELD. Yes, the gentleman from Massachusetts.

Mr. MARKEY. The Bush administration has a copy of the report.

I recommend that our committee ask the Bush administration to

give us a copy of the report, which they have, and I would make

the request from the committee.

29

Mr. BARTON. Again on my parliamentary inquiry, according to

our speaker of the legislative branch, we are supposed to produce

a bill by June. It is early to mid-March. Fifty people contributed

to this report, according to the summary sheet. Only one is with

us, Dr. Hegerl, and yet we are asked to make major policy decisions on our economy without seeing the base documents. That is

an impossible situation to put the Congress in.

Mr. BUTTERFIELD. Well, it is an impossible situation to put the

witness in. He said that it is not available and he will make it

available when it is plausible.

Mr. BARTON. I am not recommending this, Mr. Chairman, but I

believe if we subpoenaed the report, we could get it.

Mr. BUTTERFIELD. All right. Your comments are in the record.

The gentleman may resume.

Mr. BARTON. Well, start the clock for me, Mr. Chairman.

Mr. BUTTERFIELD. All right. Let us restart the clock. 5 minutes.

Mr. BARTON. My first question I think is going to be to Dr.

Hegerl. On page 2 of the summary, down in the middle of it, it says

that carbon dioxide is the most important anthropogenic greenhouse gas. I am probably mispronouncing anthropogenic but that

means manmade. What is the most important greenhouse gas, period, not just manmade but in totality, natural or manmade?

Ms. HEGERL. That would be water vapor.

Mr. BARTON. Water vapor. And what percent of water vapor is

manmade?

Ms. HEGERL. I would defer. I would just repeat what Dr. Hurrell

just said. Water vapor is a very powerful natural greenhouse gas.

It would have quite substantially cooler temperature on Earth if it

weren’t for the natural greenhouse gas water vapor. Adding CO2 to

the atmosphere changes the balance, the heat balance of the planet.

Mr. BARTON. My understanding is that water vapor is 95 percent

of the greenhouse gas. Would you agree with that?

Ms. HEGERL. I don’t know the exact numbers.

Mr. BARTON. All right. My understanding is that water vapor is

about 95 percent and that manmade carbon dioxide is about 4 percent. Does anybody on this panel dispute that?

Ms. HEGERL. No, but we are changing the balance, the overall

balance.

Mr. BARTON. But you will agree that of greenhouse gases, water

vapor is well over 90 percent and manmade CO2 is under 5 percent? That is a factor of approximately 20 to 1.

Mr. OPPENHEIMER. Could I clarify? I think what you are referring to is the natural emissions of carbon dioxide are about 95 percent of total emissions and the human emissions are at 4 percent

of total carbon dioxide emissions.

Mr. BARTON. Well, I think we have to have some perspective because this report, the summary of the report that nobody has seen

except for 50 very important people and maybe a few in the Bush

administration is based on manmade emissions. In point of fact,

natural emissions overwhelm manmade emissions.

I want to go to page 4 of the summary. I am going to ask Dr.

Christy a question. These radiative forcing components in the

30

charge on page 4 are in watts per meters square. They only list

manmade forcing components. Is that the way you read that chart?

Mr. CHRISTY. Yes.

Mr. BARTON. OK.

Mr. CHRISTY. Except for the solar forcing.

Mr. BARTON. Now, what is the most important radiative forcing

component in totality in terms of temperature change?

Mr. CHRISTY. Well, you would start with the sun and then the

water vapor in the atmosphere and clouds and so on are the biggest——

Mr. BARTON. And if the manmade component has a positive total

net radiative forcing change of about 1.5 or 1.6 meters squared, if

we put the same kind of table for clouds, where would that be on

the chart?

Mr. CHRISTY. It would be about this far out from the page.

Mr. BARTON. We can’t put ‘‘this far out’’ in the record. In terms

of watts per meters squared, where would it be?

Mr. CHRISTY. The net effect would be in tens of watts per meters

squared.

Mr. BARTON. Tens of watts. Now, is water vapor the same thing

as clouds?

Mr. CHRISTY. I am talking about the total impact of that.

Mr. BARTON. Dr. Hegerl or Dr. Hurrell, do you disagree with

what Dr. Christy just said?

Mr. HURRELL. I agree that water vapor is the dominant greenhouse gas.

Mr. BARTON. And do you agree that in order of magnitude, it is

100 times larger than the net manmade effect?

Mr. HURRELL. I am not sure about the factor of 100. I believe,

as I said, that those are very large effects, that the natural system

is in balance so the emphasis on the anthropogenic part is because

it throws the natural balance out of whack. That is why the anthropogenic component is important.

Mr. BARTON. Now, my next question I guess will be to Dr.

Hegerl. Again, back on page 2 down in the footnotes, the very last

sentence says that a number of uncertainty ranges in the Working

Group I third assessment report corresponded to 2-sigma, 95 percent, often using expert judgment. Does that mean that the uncertainty range is close to 100 percent?

Ms. HEGERL. No, that just defines which uncertainty ranges are

given conventionally in the report.

Mr. BARTON. Well, but if you have a normal bell curve, 50 percent is right in the middle and then you have these ranges. Each

sigma range goes out from the center. If I understand correctly, if

you have got a 2-sigma difference, you could be 100 percent off or

50 percent off either way. Or my statistics wrong? And I could very

well be wrong. It has been a long way since I took statistics in college but that is the way I remember it. When I view it, this basically says you all could be way off even using expert judgment. Is

that what that says?

Ms. HEGERL. The 95 percent range indicates a chance of five out

of 100 or one in 20 to be outside that range, which is a quite small

chance.

31

Mr. BARTON. Mr. Chairman, my time has expired. Are we going

to have a second round?

Mr. BOUCHER. Well, I think that depends on how long the first

one goes and how busy members are and how patient the panel is

willing to be. So the answer is undetermined at this time. We will

see.

Mr. Markey is recognized for 8 minutes.

Mr. MARKEY. I thank the Chair very much.

The average temperature for a human being is 98.6. You increase

our temperature by 3 degrees, that individual now has some problems. They are visiting the doctor, just the 2- or 3-degree change.

Or to think of it another way, on a seesaw, there is 1,000 pounds

on one side and 1,000 pounds on the other side. It is an equilibrium. But you put 20 more pounds on one side or the other and

it throws the whole system out of whack, and that is essentially

what is happening whether it be human temperature or it be nature itself. When you have relatively small changes in something

that is in equilibrium, you get rather dramatic changes in terms

of the whole direction of a seesaw or a human being’s health.

So Dr. Oppenheimer, in your testimony you suggest that the

greatest impact of global warming on the United States and for the

world may come from rising seas. But you also say that there is

a lot of uncertainty about how the ice sheets in Greenland and Antarctic will behave as the planet continues to warm up. If both the

Greenland ice sheet and the West Antarctic ice sheet were to melt,

you say we could see a 40-foot increase in sea levels, 23 feet and

17 feet. What would be the consequences of that kind of rise in sea

levels, Doctor?

Mr. OPPENHEIMER. A 40-foot rise would, for instance, bring the

Gulf Coast up to about the level of Houston and all the land between that and the current Gulf Coast would be submerged. A

third to about half of Florida actually would be permanently submerged. It would be a world-shaking change. I want to emphasize

that I don’t think any scientist thinks that that kind of sea level

rise could play out totally in a matter of even a century. It would

take at least, by my own reckoning, four or five centuries at minimum but the rates of sea level rise between now and then would

be staggeringly high. They would be on the order of a couple of meters per century. We can’t deal with that.

Mr. MARKEY. So you note that the IPCC projection of a 7- to 15-

inch increase in sea level excludes rapid dynamical changes in ice

flow. Why was that excluded? Was it because the IPCC felt those

kind of changes were unlikely or because scientists didn’t know

how to model them yet?

Mr. OPPENHEIMER. It was because scientists at the current time

do not have a model and you need a model to project forward. They

do not have a model that can accurately reproduce what has happened to the ice sheets recently in the last few decades and therefore they do not trust the projections of those models in terms of

projecting the behavior of the ice sheets over the next several decades and certainly not over the next several centuries. So at this

point there is a lot of scurrying around in the community of

glaciologists to try to better understand what our observations of

the ice sheets mean, to construct an advanced model to be able to

32

project better, and to interpret climates of the past to tell us what

they say about what the ice sheets did when Earth was warmer a

long, long time ago.

Mr. MARKEY. So would it be fair to say that there is an unknown

unknown out there with respect to the melting of those polar ice

sheets that could make the problem much worse than what the

IPCC has found thus far?

Mr. OPPENHEIMER. I think you are drawing on former Secretary

Rumsfeld’s description of uncertainty and I would rather refer to

it as a known unknown than an unknown unknown.

Mr. MARKEY. But is it a fair conclusion to say that is possible?

Mr. OPPENHEIMER. Yes.

Mr. MARKEY. Regardless of the description of it, is the conclusion

accurate?

Mr. OPPENHEIMER. I am sorry. Could you repeat what the conclusion was? I got lost in the metaphor.

Mr. MARKEY. Is there an unknown out there or a known unknown, as you want to describe it, that the melting of the ice

sheets could be far worse than the IPCC report?

Mr. OPPENHEIMER. Yes, that is certainly true.

Mr. MARKEY. OK. Well, that is the important thing to get on the

record.

Mr. MARKEY. For the other panelists, how concerned are you

about a possible disintegration of the Greenland and West Antarctic ice sheets, and do you concur with Dr. Oppenheimer’s testimony that loss of large parts of the polar ice sheets and a very

large sea level rise over the course of several hundred years rather

than over a millennium would occur once the world warms up as

little as 3 or 4 degrees Fahrenheit. Do you all agree on that?

Mr. HURRELL. I will speak just very briefly. Yes, I agree. I agree

with Dr. Oppenheimer’s main points and again, I point to the

paleoclimatic evidence going back where we know that for instance

in the last interglacial, much of the Greenland ice sheet was melted and sea levels were indeed much higher than they are today and

so I think that is a very real possibility.

Mr. MARKEY. Thank you.

The other witnesses quickly?

Ms. HEGERL. I agree with the overall statement too and I would

like to remind that the lower limit of sea level rise is largely driven

by factors we understand much better than the disintegration of ice

sheets. For example, the simple temperature effect on ocean water

expanding. So the lower limit is far less uncertain than the upper

limit.

Mr. MARKEY. Thank you.

Mr. AVISSAR. Yes, if there is warming, the ice sheet will melt and

that will increase the sea surface level, no doubt.

Mr. MARKEY. Dr. Christy?

Mr. CHRISTY. This is a very complicated issue but I would like

to say that a thousand years ago, Greenland was much warmer

than it is today for centuries at a time and yet it evidently did not

experience any kind of dramatic change at that point.

Mr. MARKEY. Thank you. Let me move to you then, Dr. Christy.

On page 8 of your testimony and in your oral testimony, you said,

‘‘It disturbs me when I hear that energy and its byproducts such

33

as CO2 are being demonized when in fact they represent the greatest achievement of our society. Where there is no energy, life is

brutal and short,’’ and you are quoting of course the famous philosopher, David Hobbs, who actually said that life for man in a state

of nature was nasty, brutish and short but Hobbs, Doctor, was actually arguing for the need to have governments in place to address

the needs and wants that make this so, lack of food, lack of security, et cetera. For Hobbs, government was the leviathan, a huge

beast, but he argued that it was a necessary beast so our challenge

is whether governments will respond to the challenge that scientists are opposing right now. If we fail, we may well return to

a Hobbsian state of nature, brutal and short, but that is the point

he was making, that governments must then work to minimize it.

So to the extent that yes, science does demonize, science has demonized asbestosis. Science has demonized tobacco. Science has demonized exposure to radiation. It doesn’t mean that they all don’t

have a role but the warning comes as to what the negative consequences are as well and so if you want to characterize that as

demonization, I think you have a right to do so but I think you

misquote Hobbs and I also think you understate the role historically that science has played, Doctor, in giving us the warnings not

just of the benefits of science, the benefits of technological advancement but also the negative consequences. So there is a Dickensian

quality, in other words. It is the best of technologies and the worst

of technologies simultaneously. It can both do good and harm at

the same time, and I would just appreciate your comment on that.

Mr. CHRISTY. OK. I didn’t see or hear a question but I think the

basic thing I want to——

Mr. MARKEY. No, I asked for a comment.

Mr. CHRISTY. OK. The basic point I wanted to get across was

that people like me are alive today and you as well because of the

technologies energy has brought us and because of that CO2 that

is in the atmosphere now and that is a point that needs to be really

emphasized, and in my experience in Africa, I keep going back to

that because energy demand will rise tremendously. We see it right

now in those countries. And when I saw that chart up there about

the U.S. emissions, I don’t think any of those are going to happen,

but when you throw in the rest of the world, I don’t see how something short of a global recession or depression would cause CO2

emissions to fall.

Mr. BOUCHER. Thank you very much, Dr. Christy.

Thank you, Mr. Markey.

Mr. Shimkus for 5 minutes.

Mr. SHIMKUS. Thank you, Mr. Chairman. And I have enjoyed

this. I am old Army infantry guy and we had the acronym—it is

not politically correct but it is ‘‘Keep it simple, stupid,’’ the KISS

formula, and that is what a lot of us try to make through all this

science and stuff. I also, at the risk of being defined as a Neanderthal, because a lot of this is secular humanist debate, I am a

creationist so I believe in the big picture; God is in control, but God

also calls us to be good stewards, and I think that is kind of par

of this debate which I don’t mind and I think it is going to be helpful because Mr. Christy’s comments about life in a carbon world

and the benefits provided by a carbon world is undeniable. The life

34

that we live as middle-class Americans—maybe I am not in that

category anymore but my family sure was when I was being

raised—because electricity and power allowed us to have a standard of living that, I am one of seven kids, probably half the kids

would have died in the Middle Ages if it weren’t for the carbon

world in which we live, and we can’t just throw that out of this debate, which brings up a lot of great questions because we hear the

term ‘‘balance’’ so the first question—and really, the only way we

are hearing so far about balancing is capping carbon dioxide, capping emissions of carbon dioxide and whether that is arguable or

not, whether we can do it or even maintain it. Is there a way to

put a balance without capping carbon dioxide? Why don’t we just

go quickly though because I don’t have that much time.

Dr. Hurrell, do you think there is a way to reclaim this balance

without—my staff is going to have to give me the formula, CO2 and

all the different strata of the atmosphere and what is going on.

Can we emit something up into the atmosphere to help create a

balance? Is there something proactive we can do that would be less

costly that would create more balance than just destroying our ability to use the fossil fuel society and which we benefit from?

Mr. HURRELL. Yes. I don’t think any of us are interested in destroying the society and the technology that we benefit from. There

is a certain level of climate change that we are committed to, as

Dr. Hegerl spoke to.

Mr. SHIMKUS. I apologize. I only have little more time. Is there

something that we can do other than capping carbon?

Mr. HURRELL. If you are referring to geo-engineering techniques,

other things that we can do to help restore this balance, that is a

topic of discussion that was very, very early my concern. With all

of those approaches, there can be unintended consequences.

Mr. SHIMKUS. OK, I don’t have time to go through all of the

whole panel. Is there anybody that feels strongly on this debate?

Mr. OPPENHEIMER. Yes, I would just say that ultimately, we have

to come to grips with the carbon problem, but that that could include efforts like the ones you heard of yesterday at carbon capture

and storage or enhancing terrestrial sinks, or in other words, increasing biological production in forests. There are many ways to

skin the cat, but in the end, carbon dioxide has to be limited.

Mr. SHIMKUS. I understand the report is not going to be made

until May and I understand that, but it is in the releases of what

people think is coming out. One would be that the hockey-stick aspect is not going to be part of this second report. Can you confirm

or deny? And if is not, why?

Ms. HEGERL. The report has a section that talks the

paleoclimatic perspective about our understanding of how temperatures in the last half-century compared to temperatures in the last

I think 1,300 years. It is on page 10.

Mr. SHIMKUS. So you are telling me it is going to be included?

Mr. HEGERL. The discussion of temperature over the last millennium is definitely included.

Mr. SHIMKUS. So the hockey-stick graph and the proposals on

that premise will be in this next report?

Mr. HEGERL. The report discusses temperature changes over the

last millennium, and we understand a lot more about how temperaVerDate 11-SEP-98 09:57 May 30, 2008 Jkt 000000 PO 00000 Frm 00039 Fmt 6633 Sfmt 6633 Q:\DOCS\110-14 SCOM1 PsN: SCOM1
35

ture evolved over the last thousand years and also what caused

many of these changes. Many of these changes were influenced by

things——

Mr. SHIMKUS. OK, let me ask one last question, and I apologize

again. I have have 5 seconds left.

I had dinner with a classmate of mine who is a NASA astronaut,

and of course, he has been up twice now, and what he says, which

is an interesting perspective, is when you are up in space and you

look at the atmosphere, and it is very thin, we are our own little

spaceship traveling through time. Does any of this global warming

affect the destruction of atmosphere as we know it? We are talking

about climate change and temperatures, but would it affect the

breakup of atmosphere as we know it? Does anybody think it is

part of that?

Mr. OPPENHEIMER. Are you asking whether it would affect the

breakup?

Mr. SHIMKUS. Yes. I mean, is Earth at risk of just destroying and

being a rock plummeting through space now?

Mr. OPPENHEIMER. Probably not.

Mr. SHIMKUS. Thank you.

I yield back, Mr. Chairman.

Mr. BOUCHER. Thank you, Mr. Shimkus.

That was certainly a reassuring answer.

Mr. OPPENHEIMER. With 90 percent confidence.

Mr. SHIMKUS. How many sigmas?

Mr. BOUCHER. Mr. Inslee is recognized for 8 minutes.

Mr. INSLEE. I defer.

Mr. BOUCHER. Mr. Inslee chooses to defer, and we will return to

you at a later point. Mr. Burgess is recognized for 5 minutes.

Mr. BURGESS. Thank you, Mr. Chairman, and I thank the panel

for a lively and thought-provoking discussing. Now, unlike the

chairman who got a full summary, I only got two pages, so I don’t

want anyone to think I am intellectually constrained, only talking

about two pages, but that is all I was given.

Now, Dr. Christy, can I ask you, I was most intrigued in your

testimony. I didn’t actually find in it in the written part that you

submitted for us about the discussion that we just had with Mr.

Markey about how life was brutal and short without adequate energy and how energy does make a difference and has made a difference to the quality of life that we all experience and has allowed

us all to live longer and healthier lives. If we were willing to sacrifice that and said that is not something that is of any value, and

we were wanted to go with metaphysical certainty to where Kyoto

would have taken us and beyond, let us say we were to go to 60

percent below the 1990 levels, and say we could do that in the next

couple of years. A hundred years from now, have we really helped

things?

Mr. CHRISTY. Well, I don’t think you would be reelected if you

ran on that platform and actually did it. The economy would be almost totally destroyed if you are talking about 60 percent reduction

in CO2 emissions right now. The only way I see something like that

happening is a massive nuclear power——

Mr. BURGESS. But if we did?

36

Mr. CHRISTY. It would be very, very tiny if just the United States

was doing what you said.

Mr. BURGESS. Well, would we prevent a hurricane? Would we

prevent a Katrina?

Mr. CHRISTY. No, Hurricane Katrina was a category 3 when it hit

the coast.

Mr. BURGESS. Well, then I guess it leads the question, are we

thinking about this problem in the correct way? If our goal is to

eliminate carbon from the atmosphere in the form of carbon dioxide

and the only way to go about it is to scale back the economy in

ways that are really almost incomprehensible to me because of the

costs of human suffering that would be involved, are we going

about this the right way?

Mr. CHRISTY. Well, that I don’t know. I don’t sit in your seat and

see all that you are doing.

Mr. BURGESS. Well, therein is part of the problem. And Chairman Barton alluded to it. And I mean under the summary for policymakers, I have got pages 9 and 10, and on page 9, which has

the table 2 for policymakers, we have the likelihood of a trend occurring the last 20th century, second column, likelihood of a human

contribution to an observed trend, and column 3, the likelihood of

future trends based on projections of the 21st century. And on that

middle column, I guess, is where I would like to concentrate, and

if you would look at the last four areas that are studied. We are

left with a designate of ‘‘more likely than not.’’ And this includes

heat waves, heavy precipitate, areas affected by drought, tropical

cyclones increase, and increased incidences of extreme high sea levels. All of those things scored more likely than not. Have I got that

right of what you have got on that table? Help me understand—

and you already alluded to my reelection—to me more likely than

not more mean 50.1 percent if it was a two-person race, but could

be as low as, as we saw in Texas, 39 percent, if you have a fourperson race. So what is the percent of more likely than not?

Mr. CHRISTY. As I understand it, it is 51 percent. Is that right?

Ms. HEGERL. It is greater than even odds, so 50 percent or greater.

Mr. BURGESS. Fifty percent, but that is only assuming that there

are two eventualities. If there were a third in there, then that

would reduce it even further, correct?

Ms. HEGERL. No, the four last instances are based on aspects of

the climate system which we don’t model very well, and which we

cannot very confidently, at this point, attribute——

Mr. BURGESS. Mr. Chairman, I am going to run out of time. I

guess what I would like to ask, if it is possible, and I may not have

asked this very well, but I will try to submit this in writing to the

entire panel. I would like to get your thoughts on that.

And just finally one last question—and I know this is true because I read it on a blog on the Internet—we are assuming that

there is an absolute constant. I guess, Dr. Christy, you said in regards to global warming that solar radiation is the number one

source for global warming. Is that a fair statement?

Mr. CHRISTY. It is the source of our energy that runs our system,

yes.

37

Mr. BURGESS. Correct, well, assuming that none is coming from

the Earth’s core, and I don’t know if that is still molten or not. It

was when I when I was in high school. It may not be anymore. Of

that solar radiation, is that an absolute constant?

Mr. CHRISTY. No, solar radiation varies, but what varies more

would be, for example, the cover and constitutes in the atmosphere

that would affect the Earth more.

Mr. BURGESS. But all of these assumptions, at least to my

uninitiated eye, would mean that the solar contribution is an absolute constant, that it never changes.

Mr. OPPENHEIMER. No, that is not true. IPCC looks around carefully at that question, and we know very well what the solar variations have been over the last 30 years or so because we have satellites that stare at the sun all the time. And they have given us

the indication that the sun’s variation in the last 30 years when

Earth has been warming a lot has been tiny. A tiny percentage, it

can account for only a very, tiny percentage of the warming. And

even looking back 250 years, changes in the sun could only account

for less than 10 percent of the warming that has occurred.

Mr. BURGESS. Which brings me to the blog on the Internet and

that apparently Mars too is afflicted with global warming and the

reduction in size of their ice cap. Are humans responsible for the

Mars problem as well?

Mr. OPPENHEIMER. Mars is afflicted with a greenhouse effect,

just like we are, but we have an increase in greenhouse effect. And

Mars probably doesn’t.

Mr. BURGESS. Thank you, Mr. Chairman. You have been very indulgent.

Mr. BOUCHER. Thank you, Mr. Burgess. I totally neglected the

time, but I am confident you used it well. Mr. Whitfield is recognized for 8 minutes.

Mr. WHITFIELD. Thank you, Mr. Chairman, and appreciate the

panel being with us today. On this intergovernmental panel, the

ICCP, whatever the initials are, how many scientists are on that

panel? Anyone that knows the answer.

Ms. HEGERL. Hundreds of—depends on how you define the panel,

the lead authors, or hundreds of lead authors. Do you remember

that exact number?

Mr. HURRELL. There were 152 lead authors and 400 contributing

authors to working group one, which deals with how the climate

has been changing and the role of human activities in that.

Mr. WHITFIELD. My understanding that, of course, you have the

lead authors for different segments of these reports. And I remember we had a hearing, an oversight investigation about a year ago,

and there was some discussion about the impact of global warming

on hurricanes and flooding and so forth. And some members of the

IPCC that were making the big report had a press conference evidently at Harvard University, and one of them made the comment

that global warming has an impact on the frequency of hurricanes.

And as a result of that, the lead author of the hurricane section

ended up resigning from the panel because he said this is more of

a political statement than anything based on science. And he resigned from the panel. Are any of you familiar with that situation

at all?

38

Ms. HEGERL. Sir, I don’t think this refers to the IPCC but to the

U.S. CCSP report, right?

Mr. CHRISTY. No, this was the IPCC, and he was not a lead author. He was a contributing author.

Ms. HEGERL. He was a contributing author?

Mr. WHITFIELD. He was a contributing——

Mr. CHRISTY. Yes, what was his name?

Mr. WHITFIELD. Chris Landsea.

Mr. CHRISTY. Yes.

Mr. WHITFIELD. Now, do any of you have any comment about

that? I mean one of the issues about all of this global warming is

that it seems to be becoming immersed in total politics. For example, there have been some IPCC reports that have said that anything below three degrees of warming in our climate, that developed countries will benefit economically and developing countries

will not benefit economically. Are you all familiar with that statement?

Mr. OPPENHEIMER. Yes, I just want to point out that that is the

arena that the second IPCC working group, which is not going to

report until April deals with. And so there will be updates on that

view, but they are not finalized yet so I can’t discuss them.

Mr. WHITFIELD. But in 2001 or 2000, they did make that statement.

Mr. OPPENHEIMER. It is a statement. I can’t remember the exact

number. Up to a certain temperature, there could be benefits in

certain areas, and the developing countries would more likely start

to suffer before developed countries like the United States did.

Mr. WHITFIELD. When the Kyoto Protocol was being agreed to by

some countries and not agreed to by other countries, there was a

cry around the whole world about how catastrophic this would be.

But 10 years ago in an article in ‘‘Geophysical Research Letters’’

they estimated that if every nation on Earth lived up to the United

Nations Kyoto Protocol on global warming, it would prevent no

more than .126 degrees Fahrenheit of warming every 50 years.

Mr. OPPENHEIMER. Yes, the Kyoto Protocol was viewed by those

who signed it as only the first step, and it was recognized that

much larger reductions would be needed if a significant difference

was going to be made in global climate. And those could only have

an effect over many, many decades. So while it is technically correct that the Kyoto Protocol would not have had much, if any,

measurable effect on climate if that was all that was ever done, the

expectation among the signatories was that wasn’t the last step but

only the first.

Mr. WHITFIELD. Yes, I think that as Members of Congress, not

only in United States but around the world, it is helpful if we all

could be less emotional on this issue because when the U.S. failed

to sign this Kyoto Protocol, it sounded like the world was coming

to an end. The U.S. was being so irresponsible. So I think if we can

make this less sensational in any way possible, that we all benefit

from that. And then a second part of this that certainly concerns

all of us is the cost of global warming and the cost of preventing

global warming. And I know at one time the IPCC, they looked at

cost/benefit analysis, and then they reach a point where they said

we are not going to consider cost at all. And then you had some,

39

I guess, people who developed some models to look at cost, one referred to as Dice, now, tell me about Dice.

Mr. OPPENHEIMER. Dice is an economic model which attempts to

look at the balance between costs of reducing emissions and the

damages from not reducing emissions and seek what the optimum

balance is over the course of the next century.

Mr. WHITFIELD. Now, why would the IPCC not be involved in

looking at that as well?

Mr. OPPENHEIMER. Well, in fact they have been, and again the

report on economic consequences won’t be out until May. And I am

not involved with it, so I can’t speak about it. But the last IPCC

report, they did publish different ways to look at that balance, and

a crude way to look at it is if the atmosphere, the cost of restricting

warming to remain near those lower curves that you showed before, would be several percent of global GDP cumulative over the

next 50 years. That is not several percent per year. That is several

percent cumulative over 50 years, and the cost of the known damages were roughly the same; that is, excluding things like a large

rise in sea level due to the loss of the ice sheets. So many economists said well, if those two things are in balance, we ought to

start doing something about it. And that is what the Dice model

shows, that a current investment makes sense.

Mr. WHITFIELD. OK.

Mr. BOUCHER. The time of the gentleman has expired.

Mr. WHITFIELD. Thank you.

Mr. BOUCHER. Mr. Inslee for 8 minutes.

Mr. INSLEE. Thank you. Just kind of a bonehead question. CO2

warms the planet. What would the mean temperatures of the planet be if there were no CO2 in the atmosphere? Dr. Hurrell, do you

want to start on that? Just, by an order of 300 percent.

Mr. HURRELL. Yes, it is like a 33-degree Celsius difference, I believe, with no greenhouse gases.

Mr. INSLEE. So no——

Mr. HURRELL. Fifty-one?

Mr. HASTERT. Are we talking about——

Mr. HURRELL. I was talking about the total greenhouse——

Mr. HASTERT. He just asked about CO2. Mr. INSLEE. Yes, let us start with greenhouse gases. Roughly

how much colder would it be?

Mr. HURRELL. Total greenhouse gas?

Mr. INSLEE. Yes, total greenhouse gas.

Mr. HURRELL. Thirty-two degrees.

Mr. INSLEE. OK, how about carbon dioxide any ideas at all? Just

don’t know.

Mr. HASTERT. Can I ask it would be 32 degrees colder?

Mr. HURRELL. Yes, the planet is warmer by 32 degrees Celsius

because of the greenhouse gas effect. That includes the natural

greenhouse gas effect from water vapor as well as——

Mr. HASTERT. And so if we are at zero Celsius right now, just say

we are, we would be 32 degrees Celsius below the point we are at

now?

Mr. HURRELL. Right. Well, go ahead.

Ms. HEGERL. Well, there wouldn’t be an atmosphere so we would

have no weather.

40

Mr. INSLEE. So the reason that concerns me is that we are going

to be about twice pre-industrial levels of at least one major greenhouse gas, CO2, in the next century or so unless this Congress

pulls its head out of the sand and does something. So that means

if you go down with somewhere in the neighborhood of 30 Celsius,

there is going to be big impacts in the world if we don’t do something. And that may not be a one-to-one correlation, but I am just

telling you how one congressman looks at that concern about how

significant greenhouses gases are to the climatic systems of the

Earth. We are going to be at double the levels that we had in preindustrial times. Now, I am really glad that Dr. Christy came here

because I——

Mr. BARTON. Would the gentleman yield?

Mr. INSLEE. If you will give me some more time.

Mr. BARTON. Your questions are very important, and you are one

of the most knowledgeable congressmen on this issue. I mean you

really are. You were very patient in the minority, and you have

every right to be a lot more impatient in the majority. But I want

it to be clear that this 32-degree Celsius change, most of that is

natural. It is not manmade CO2. It is water vapor that 95 percent

is natural water vapor.

Mr. INSLEE. I understand that, and I want to come back to Mr.

Barton’s comment, which I think is probably accurate, that only

about 5 percent of the CO2 emitted in the atmosphere is from

anthropomorphic sources. Now, the reason that statistic is cited because it sounds like a diminimus amount.

However, that is a 5 percent unnatural, if you will, increase to

the net zero that occurred in pre-industrial times. That means it

is like eating doughnuts for the next 20 years. If we all ate enough

to gain 5 pounds a year, enough doughnuts, which I will call the

unnatural part of our diet in our atmosphere, we are adding carbon

dioxide doughnuts. And every year it goes up 5 pounds, or 5 percent. Now, that means in 20 years, I would weigh 400 pounds. So

that 5 pounds didn’t sound like much, but what I am pointing out

here is we are heading to a level of double the CO2. And CO2, if

we look backwards, when you double something, it has a major impact. We know we could be in a frozen planet if we had half as

much CO2, and if we have double the amount CO2, it is very concerning. That is my reaction to this.

Now, I want to ask Dr. Christy a question. I am glad you came

because listening to your testimony, what I am hearing you saying

is yes, carbon dioxide is playing a role. I don’t think you said the

majority role, but some of the role of climate change. And you

talked about your work that I respect as a missionary in Africa,

and what I take from you is you sort of assume that if we do something about CO2, we are going to all go back and live like the people do in Africa in that terrible poverty that you worked diligently

to aid.

But I want to quote a group called Christian Aid. It is an evangelical missionary and development organization. They have

worked in Africa for 50 years, and here is what they say. ‘‘It is vulnerable people in poor countries that are affected first and most seriously. Climate change is the most significant single threat to development. It could undo decades of progress in fighting poverty.’’

41

Christian Aid believes that a new global agreement must be

reached to cut emissions and provide help to poor people who are

on the receiving end of global warming. Any such agreement must

be based on scientific, not political, targets.

Now, what I understand your sort of working hypothesis, Dr.

Christy, is for us to do something about this, we are going to have

to go back and live in the stone ages. And the reason is that you

just don’t believe that mankind has been given an intellectual capability sufficient enough by the creator to develop technologies to

deal with this that don’t put CO2 in the atmosphere. Now, that is

the working assumption that sort of underpins your testimony. So

I want to ask you do you about the Nanosolar Corporation out in

California?

Mr. CHRISTY. I was delighted to hear that you were on the subcommittee.

Mr. INSLEE. Just answer the question. Do you know about

Nanosolar Corporation?

Mr. CHRISTY. I probably read about it, but I could not recall anything.

Mr. INSLEE. Do you know about the A123 Battery Company?

Mr. CHRISTY. No, I don’t.

Mr. INSLEE. OK, just so you will know, they are a company that

has developed a lithium ion battery that could potentially run a car

for 40 miles with zero CO2. Do you know about the general compression company?

Mr. CHRISTY. Americans are innovative, and they can provide

ways to create energy that doesn’t use carbon dioxide. And I am

all for it if I don’t have to pay twice as much.

Mr. INSLEE. Right, so the general compression technology, basically they have a way of compressing air to create a battery system

to use compressed air to become essentially a battery for wind turbine technology that they believe could increase by a factor of two

the efficiency of a wind turbine system because it can make an

intermittent power to be stable, base load power. What percentage

increase of technology do you believe Americans can create in the

next 20 years, per year, as an increase, let us say, in efficiency?

What number do you believe we can increase per year and not reduce our economic growth?

Mr. CHRISTY. I want to respond to that Christian missionary

thing. I am a Christian missionary and a climate scientist. So I can

talk about both those sides. I don’t think those folks can. The problem in Africa is governance.

Mr. INSLEE. Well, let me tell you there is another problem in Africa.

Mr. CHRISTY. The question about if I were just to guess and that

is all it would be would be a guess, is that to get those systems

into the current energy distribution and generation system would

take decades from what I understand the situation is now, except

for nuclear.

Mr. INSLEE. And I appreciate that comment, and I think to some

degree it is accurate. But let me suggest that the fact that it will

take decades for us to rebuild our economy, to be largely carbon

neutral, is not an argument for delay. It is an argument for hastening action. The fact that it is going to take us some time and that

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there are some uncertainties about global warming and that there

are uncertainties about what technologies we are going to use, isn’t

that an argument to get started this year in Congress, rather than

an argument to wait?

Mr. CHRISTY. When you say get started, that is where I worry

about the people in Alabama who are struggling to pay their energy bills now.

Mr. INSLEE. I understand that, and if the people of Alabama

would adopt some of the things that we have done in other States

like California, we could reduce our energy by 50 percent. The people in Alabama have increased their per capita consumption, and

I don’t know Alabama for sure, but nationally, by 50 percent over

the last 20 years. The people in California who are still enjoying

hot tubs and they have still got a booming economy have had a flat

rate of growth in energy per capita in the last 20 years because

they have responded to this. So I am glad you came. Thank you

very much.

Mr. CHRISTY. Thank you.

Mr. BOUCHER. Thank you, Mr. Inslee. Mr. Sullivan is recognized

for 5 minutes.

Mr. SULLIVAN. Thank you, Mr. Chairman, and this is complicated, climate change, global warming. I am trying to learn a lot

about it. I don’t know much about it, and maybe some of you could

help me with some of these things. I heard today that Chairman

Markey said that—or I think Mr. Oppenheimer might have said

that sea level would go up 40 feet, and that scares me. A lot of people would probably die if that happened. Also, I think Mrs. Hegerl

had said that—you were talking about some modeling and some

temperatures from 1,300 years ago until now, and that there has

been some dramatic change. I like using dynamic economy models

here for tax relief, and a lot of people don’t like those. Say that my

modeling is wrong, and I think there is always room for error in

these modelings. Let us talk about 1,300 years ago, Mrs. Hegerl.

What kind of meteorologists were on the planet and what kind of

thermometers did they use? And where were the weather stations?

Let us just say 500 years ago, what kind of thermometers? I am

just curious.

Ms. HEGERL. To reconstruct temperatures over the last millennium, we use proxy data that, for example, reading that approximately respond to changes in temperature. So you can reconstruct

with uncertainties temperatures over the past based on indicators

that follow the climate——

Mr. SULLIVAN. With uncertainty?

Ms. HEGERL. With uncertainty. On the other hand, when we try

to understand what happened in the last millennium, we also have

indicators of what influenced climate, and those are virtually independent. For example, entries in ice course in Greenland and Antarctica, that indicated what kind of corruption and the correspondence between those two things, which are virtually independent

really, gives us some confidence that we can understand to what

extent what happened in the past and also that we are not completely blowing reconstructing the past.

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Mr. SULLIVAN. And we talked about this naturally occurring phenomenon of the water affecting the environment, and I believe 96

percent is natural. Is there anything we can do to change that?

Ms. HEGERL. When we increase CO2 in the atmosphere, you have

a bank with water vapors. The water vapor increases as we increase CO2. It is a positive feedback, so when we exchange——

Mr. SULLIVAN. When you say that is climate models.

Ms. HEGERL. It is also been observed. Both the vapor increases

have been observed.

Mr. SULLIVAN. And so you are saying that you can do these models with absolute certainty of temperatures?

Ms. HEGERL. No.

Mr. SULLIVAN. That is what you said earlier.

Ms. HEGERL. No, I am not saying we are doing with certainty.

Mr. SULLIVAN. That is neat if you can. I don’t know much about

science. I didn’t know that that could happen.

Ms. HEGERL. No, but the IPCC has predicted through to temperatures since 1990, and we have done relatively well predicting

what would happen in the 15 years since the process started. It has

been warming, and it is within the range that we predicted.

Mr. SULLIVAN. And would you agree, any of you, that this is pretty complicated stuff, and we need to move cautiously when we

make major decisions? Would most of you agree with that? The

Speaker wants us to have a bill by June to fix all this. Do you

think that that is kind of a rush timeframe to get this done, that

we should look at this and examine it very carefully?

Mr. OPPENHEIMER. I think that is your decision, not ours.

Mr. SULLIVAN. But wouldn’t you agree?

Mr. OPPENHEIMER. I think the problem should be looked at carefully, but we have a very large body of knowledge. It has been accumulating since 1896 on this problem. There are reports stacked

that thick—I think it is probably possible with reason by June——

Mr. SULLIVAN. Well, Doctor, we can fix this tomorrow then?

Mr. OPPENHEIMER. You could get advice on how to fix it, but it

wouldn’t be completely fixed for many decades, if then.

Mr. SULLIVAN. Well, with all the modeling that you do, do you

do any modeling of how this will affect the economy and——

Mr. OPPENHEIMER. It has been done.

Mr. SULLIVAN. And would it be detrimental to the economy?

Mr. OPPENHEIMER. There are different views. It is not going to

happen, but if the U.S. had implemented the Kyoto Protocol, the

estimates were about a 1 percent decrease in total GDP cumulative

over the 10 years of implementation, according to the midrange of

the models. In other words, about a tenth of a percent per year.

Mr. SULLIVAN. OK. Well, Dr. Christy, is it correct that you have

constructed observational data sets?

Mr. CHRISTY. Yes, we build them from scratch.

Mr. SULLIVAN. Can you elaborate on what is involved in the observational work you do?

Mr. CHRISTY. We do everything from going to libraries and getting the paper records, dusting them off and digitizing them, to getting the digital counts from satellites to create upper air data sets.

I mean we start from scratch, and very few people in the world,

by the way, actually do that.

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Mr. SULLIVAN. That is good. Also I guess I am curious, all the

panelists, how many of you have put together observational databases from scratch? What type of actual climate observational

work, not climate modeling, do you do?

Mr. HURRELL. I have not put together an observational data set

from scratch. I am, however, a climate diagnostician. I do not build

models. I primarily have analyzed observational data sets my entire career.

Mr. SULLIVAN. So you haven’t done it?

Mr. BOUCHER. Thank you, Dr. Hurrell. The gentleman’s time has

expired. Mr. Walden for 5 minutes.

Mr. WALDEN. Thank you, Mr. Chairman. And I appreciate the

testimony of the witnesses, and my apologies for having to kind of

come and go. It is that season here on the hill where everybody is

in town, and we are generally triple booked. Dr. Christy, it appears

that models get the global average temperature simulations to

match some global average surface temperature observations. But

do models get the patterns of warming that has been observed correctly?

Mr. CHRISTY. In the data sets we construct, the answer is no,

and it is a little bit misconception to say that they match even the

global temperature because remember modelers already know the

answer ahead of time. So matching that was not that great of a

feat when it was designed to match the last 100 years of climate

records.

Mr. WALDEN. Does that mean then that they somehow manipulate the data to get to the temperatures that were supplied?

Mr. CHRISTY. No, they don’t manipulate the data, but there is a

level of what we call tuning that occurs to make sure that all the

things balance right so that the temperature matches what was observed in the global average sense.

Mr. WALDEN. Do they get the tropical patterns of warming or the

observations of warming at different altitudes?

Mr. CHRISTY. Not that we have found, no.

Mr. WALDEN. And what is the effect of that on our policymaking

here?

Mr. CHRISTY. It would be just to raise great caution about using

them as predictive tools.

Mr. WALDEN. OK.

Mr. HURRELL. Are we allowed to respond?

Ms. HEGERL. Yes, I would like to make one comment. The ocean

heat content data set came out in 2001, so by the time many more

tools were used to analyze it were built and run, the data did show

that the ocean content gained heat. And the pattern with which it

gained it has not been known to the modelers. So this is one great

example of a completely independent data set that wasn’t——

Mr. HURRELL. I would just like to on the record state that climate models are put together. They are very complex tools, trying

to represent the complexity of the climate system. But individual

processes are modeled based on our best scientific understanding.

That entire set of processes are then put in models, and the models

are allowed to freely integrate in time. So the very impressive

match on global and continental and ocean basin scales of today’s

climate models in replicating historical record are a very powerful

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statement that the models have reached a point where they are

very, very useful tools. And they give us much increased confidence

in future predictions.

Mr. WALDEN. All right, then what should we make of the science

report this summer that the upper surface of the ocean cooled substantially between 2003 and 2005, which cut by about one-fifth of

long-term upper ocean heat gain between 1955 and 2003? It doesn’t

seem to square with the IPCC summary telling us, or what the

models portray, doesn’t it?

Ms. HEGERL. Variations over a short time scale are very difficult

to interpret, and it is much more helpful to look at the longer timeframes. And those variations are interesting, and for us, as scientists, fascinating. But I would warn of trying to extrapolate them

for a longer time.

Mr. WALDEN. Well, do you see short-term variations on some of

the glaciers and all too? I am thinking in the Northwest last summer, we were told in Oregon the glaciers had receded by 50 percent. And about three weeks ago, they came back with revised forecast that it was actually 35 percent.

Mr. OPPENHEIMER. One does see short-term variations in glaciers, and they are of a surprising degree.

Mr. WALDEN. Right.

Mr. OPPENHEIMER. It turns out that ice could move much faster

than we thought. It can accelerate, and it can stop much faster

than we thought.

And that is, by the way, one of the reasons we don’t have a lot

of confidence in the models. They don’t predict such changes. Those

are the ice sheet models. That is distinct from the atmosphere climate models.

Mr. WALDEN. I understand, and I am not necessarily making the

argument the Earth isn’t getting warmer. I mean I believe we have

had thermometers, and you have got predictive models, and they

may be up and down and all that. My question though is in the

limited data that I have been trying to get up to speed on, it appears this has been an accumulation during the Industrial Age. It

has been close to 100 years that we have been, if you follow the

theory, we have been putting carbon and other pollutants into the

atmosphere that has caused this to occur. I have also read that it

could be 100 years if we got back to equilibrium before you might

see a substantial temperature change downward.

Mr. OPPENHEIMER. I think a simple way—a cartoon of the situation is if you stopped all emissions today, it would take many decades, probably about two centuries, for carbon dioxide to return to

the level of around 300 parts per million.

Mr. WALDEN. And if you get much below that, am I not correct

that we go back into an ice age? Weren’t we in an ice age in the

50 to 100 parts per million?

Mr. OPPENHEIMER. No. The last ice age came to an end about

10,000 years ago. And since then, climate has had——

Mr. WALDEN. No, my question is what was the carbon level in

the atmosphere during the Ice Age?

Mr. OPPENHEIMER. About 200 parts per million.

Mr. WALDEN. That is what I was saying. If you got down to 50

to 100, I had it lower than what you are saying.

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Mr. OPPENHEIMER. Right, but that is not going to happen.

Mr. WALDEN. I didn’t ask that. No, that wasn’t what I was saying. There is a point where you don’t want to eliminate all carbon

out of the atmosphere or you have cooling right? Again that was

the issue in the 1970’s. I remember some of those stories, The Coming Ice Age, and all that in ‘‘Time’’ magazine.

Mr. OPPENHEIMER. The likelihood is we are never even going to

get back to the pre-industrial level of 280 parts per millions. It is

simply not going to happen because we put so much carbon dioxide

in the atmosphere. If we stopped our emissions, it would gradually

fall out, but we are stuck with some of that carbon dioxide for

1,000 years or more.

Mr. WALDEN. Some of it lives a very long time.

Mr. OPPENHEIMER. Correct.

Mr. BOUCHER. The gentleman’s time has expired.

Mr. WALDEN. Thank you, Mr. Chairman, for your indulgence.

Mr. BOUCHER. Mr. Barton has asked for the opportunity to propound some additional questions, and at this time, I am going to

recognize him for an additional 5 minutes of questions.

Mr. BARTON. I am going to try to be as quick as possible, Mr.

Chairman. Thank you for your courtesy. What is the largest concentration of CO2 in the atmosphere ever as far as we know if you

go back to prehistoric times?

Mr. OPPENHEIMER. Ever?

Mr. BARTON. Ever.

Mr. OPPENHEIMER. Ever, there were times in Earth’s history

where there was much more carbon dioxide than today, but in the

time——

Mr. BARTON. Well, I mean just give me a number. I mean I am

told that plants are genetically best able to reproduce themselves

and thrive at 1,000 parts per million of carbon in the atmosphere.

Is that a true statement or a non-true statement?

Mr. OPPENHEIMER. We don’t actually have a good picture because

those levels of carbon dioxide haven’t recurred for millions and millions of years.

Mr. BARTON. But isn’t it a fact that in the past we have evidence

or we at least have theories that carbon has been much higher concentration than 380 parts per million?

Mr. OPPENHEIMER. Yes, and Earth was much, much, much

warmer.

Mr. BARTON. OK, and even you would admit those weren’t driven

by manmade emissions?

Mr. OPPENHEIMER. Even I would admit that that was natural,

but it occurred very slowly over millions of years.

Mr. BARTON. Well, but I mean the point is that we are taking

as a base period 1750 or 1850, which we are in what we at one

time called the Little Ice Age, and since that time, the temperature

has been going up, which you would assume, if you are coming out

of an ice age, it would be going up?

Mr. OPPENHEIMER. Excuse me. It was not an ice age. It was a

small decrease in temperature mostly in the North Atlantic Basin.

Mr. BARTON. It was in popular literature until recently it has

been called the Little Ice Age.

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Mr. OPPENHEIMER. Right, but it had some effects in the North

Atlantic Basin and maybe some other places. An ice age means

1,000 feet of ice reaching down to New York.

Mr. BARTON. Well, we have had higher concentrations of CO2

and higher concentrations of carbon than what we have today.

Mr. OPPENHEIMER. Right.

Mr. BARTON. That is a true statement.

Mr. OPPENHEIMER. Sure, and what we perhaps will do over this

century is return Earth’s temperature to levels that were near

what they were several million years ago.

Mr. BARTON. I want to ask Dr. Christy a question. Are clouds

critical to how warm or cold the Earth is?

Mr. CHRISTY. They are critical.

Mr. BARTON. How well do we understand the formation of

clouds?

Mr. CHRISTY. Not well at all.

Mr. BARTON. How do we account for clouds in these models that

the scientists have been talking about?

Mr. CHRISTY. Well, the grid squares on which calculations are

done are fairly large, a few hundred kilometers. And so clouds cannot be represented in that with a single point number. So they are,

in a sense, statistically represented in terms of their effects on the

radiation and so on.

Mr. BARTON. I am told that there are about 20 models that portray themselves as being able to model climate in the atmosphere

and that none of these models accurately account for clouds. Is that

a true statement or a non-true statement?

Mr. CHRISTY. Well, it hinges on accurately, and from my point

of view, I would say that is true.

Mr. BARTON. Dr. Hurrell, would you agree or disagree with that

last statement?

Mr. HURRELL. I agree the clouds are a major shortcoming of today’s climate models.

Mr. BARTON. OK, if you were a policymaker, given the uncertainty just in that one variable, how many millions of jobs would

you put at risk for political correctness? It is a fair question. That

is what we are being asked to do by the 1st of June.

Mr. HURRELL. I resent the notion that the greenhouse effect as

a problem involves political correctness. It is, in first order, a scientific issue. Whether it is worth doing anything about and how

much is indeed your own decision.

Mr. BARTON. Well, your own testimony earlier, Doctor, was that

if we totally eliminated manmade CO2 emissions, it could be several centuries before we saw any change.

Mr. HURRELL. No, I didn’t say that. I said it would be several

centuries before carbon dioxide would return even close to pre-industrial levels. That is something quite different.

We could have a substantial change on future climate by limiting

emissions, and in addition, it needn’t bankrupt the economy. That

is a false comparison, as the progress in California has shown. It

was referred to by the Member from Washington.

Mr. BARTON. My time is about to expire. Let me ask one last

question.

Mr. HURRELL. Sure.

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Mr. BARTON. Your radiative forcing components in this summary

shows that there is some manmade forcing components that are

negative. As a policy option, should we consider doing some of the

negative things that would balance the positive?

Mr. HURRELL. If you want people to be breathing dirtier air,

sure, go ahead. But I don’t think people want to solve one environmental problem on the back of another.

Mr. BARTON. OK, I thank the Chair’s courtesy, and I am going

to have some written questions for this group.

Mr. BOUCHER. Well, without objection, written questions may be

submitted to this panel. And when they are, we would appreciate

your expeditious response. Mr. Hastert.

Mr. HASTERT. I just want to thank the panel. This is what it is

supposed to be, a learning experience. One of the things we have

learned is that there is not a lot of exactness there. There is a lot

of maybe and ifs and clouds do this and maybe not and ice sheets,

and I appreciate the frankness and candidness of this panel. It has

been very helpful. Appreciate everybody being here today.

Mr. BOUCHER. And let me second that sentiment. I very much

appreciate your willingness to spend time with us today. It has

been a rather long period of time, and we thank you for your answers. Mr. Burgess, do you have a comment you would like to

make?

Mr. BURGESS. Yes, I do have a comment. We have heard some

rather intriguing science and certainly the level of uncertainty

around some of these issues that were discussed today just leads

me to believe that the timeline that we are on to produce a legislative product by June or July is absolutely untenable. And I hope

the chairman will communicate with his leadership about the hearing that we have had today and the fact that it was well attended,

at least on our side. There is a genuine willingness there to learn.

We are going to need more time to develop a legislative product

that does not put our economy at risk and still serves the needs

of generations to come.

Mr. BOUCHER. Thank you, Mr. Burgess. And let me assure you

that we are having in-depth discussions on the majority side about

the schedule.

Mr. BURGESS. I will be glad to show up and help you with those

discussions.

Mr. BOUCHER. Thank you. I might call on you to do that. Well,

with those comments, we thank our panel, and this hearing is adjourned.

[Whereupon, at 1:40 p.m., the subcommittee was adjourned.]

[Material submitted for inclusion in the record follows:]

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Statement of Michael Oppenheimer

Professor, Geosciences and International Affairs

Princeton University

Princeton, NJ

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SUMMARY OF MAJOR POINTS—TESTIMONY OF JAMES W. HURRELL—MARCH 7, 2007

ARE GLOBAL TEMPERATURES INCREASING?

The iconic statement from the observations chapter of the IPCC Fourth Assessment Report (AR4) is the ‘‘warming of the climate system is unequivocal.’’ This is

based on an increasing number of many independent observations that give a consistent picture of a warming world. A limited sample of the evidence includes:

• Average global surface temperature has warmed over the last 50 years, with

a greater rate of 0.17δC (0.3δF) per decade since 1979.

• Global average sea surface temperatures have warmed 0.35δC (0.6δF) since

1979.

• Global sea level has risen at a rate of 0.31 cm per year since 1993.

• Arctic summer sea-ice extents and Northern Hemisphere snow cover have decreased, and permafrost layer temperatures have increased since the 1980’s.

• The number of heat waves globally has increased, and there have been widespread increases in the numbers of warm nights. Frost days are rarer.

To what extent is the increase attributable to greenhouse gas emissions from

human activity as opposed to natural variability or other causes?

Climate model simulations have now reliably shown that global surface warming

of recent decades is a response to the increased concentrations of greenhouse gases

and sulfate aerosols in the atmosphere. When the models are run with natural forcing changes alone, they fail to capture the large increase in global surface temperatures over the past 25 years. Moreover, the spatial pattern of observed warming,

which includes greater warming over land than over the ocean, is only simulated

by models that include anthropogenic forcing. Discernible human influences now extend to other aspects of the climate as well, including ocean warming, continentalaverage temperatures, temperature extremes, and changes in precipitation.

How will future global temperatures be affected by greenhouse gas emissions from

human activity?

The ability of climate models to simulate the past climate record gives us increased confidence in simulations of the future. Some major conclusions from the

IPCC AR4 are:

• The rate of the projected global warming is near 0.2 Celsius per decade

through 2030 regardless of the emission scenario. Likewise, warming and significant

changes in precipitation will continue over each inhabited continent.

• By the middle of the 21st century the choice of scenario becomes more important.

• Continued greenhouse gas emissions at or above current rates would very likely induce many changes in climate much larger than those observed to date.

• Snow cover and sea ice coverage are projected to contract.

• It is very likely that hot extremes, heat waves, and heavy precipitation events

will continue to become more frequent.

• Even if greenhouse gas concentrations were to be stabilized, anthropogenic

warming and sea level will continue for centuries.

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