<DOC>
[110th Congress House Hearings]
[From the U.S. Government Printing Office via GPO Access]
[DOCID: f:37414.wais]
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
______
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COMMITTEE ON ENERGY AND COMMERCE
JOHN D. DINGELL, Michigan, Chairman
HENRY A. WAXMAN, California JOE BARTON, Texas
EDWARD J. MARKEY, Massachusetts Ranking Member
RICK BOUCHER, Virginia RALPH M. HALL, Texas
EDOLPHUS TOWNS, New York J. DENNIS HASTERT, Illinois
FRANK PALLONE, Jr., New Jersey FRED UPTON, Michigan
BART GORDON, Tennessee CLIFF STEARNS, Florida
BOBBY L. RUSH, Illinois NATHAN DEAL, Georgia
ANNA G. ESHOO, California ED WHITFIELD, Kentucky
BART STUPAK, Michigan BARBARA CUBIN, Wyoming
ELIOT L. ENGEL, New York JOHN SHIMKUS, Illinois
ALBERT R. WYNN, Maryland HEATHER WILSON, New Mexico
GENE GREEN, Texas JOHN B. SHADEGG, Arizona
DIANA DeGETTE, Colorado CHARLES W. ``CHIP'' PICKERING,
Vice Chairman Mississippi
LOIS CAPPS, California VITO FOSSELLA, New York
MIKE DOYLE, Pennsylvania STEVE BUYER, Indiana
JANE HARMAN, California GEORGE RADANOVICH, California
TOM ALLEN, Maine JOSEPH R. PITTS, Pennsylvania
JAN SCHAKOWSKY, Illinois MARY BONO, California
HILDA L. SOLIS, California GREG WALDEN, Oregon
CHARLES A. GONZALEZ, Texas LEE TERRY, Nebraska
JAY INSLEE, Washington MIKE FERGUSON, New Jersey
TAMMY BALDWIN, Wisconsin MIKE ROGERS, Michigan
MIKE ROSS, Arkansas SUE WILKINS MYRICK, North Carolina
DARLENE HOOLEY, Oregon JOHN SULLIVAN, Oklahoma
ANTHONY D. WEINER, New York TIM MURPHY, Pennsylvania
JIM MATHESON, Utah MICHAEL C. BURGESS, Texas
G.K. BUTTERFIELD, North Carolina a MARSHA BLACKBURN, Tennessee
CHARLIE MELANCON, Louisiana
JOHN BARROW, Georgia
BARON P. HILL, Indiana
____
Professional Staff
Dennis B. Fitzgibbons, Chief of Staff
Gregg A. Rothschild, Chief Counsel
Sharon E. Davis, Chief Clerk
Bud Albright, Minority Staff Director
(ii)
Subcommittee on Energy and Air Quality
RICK BOUCHER, Virginia, Chairman
G. K. BUTTERFIELD, North Carolina J. DENNIS HASTERT, Illinois,
Vice Chairman Ranking Member
CHARLIE MELANCON, Louisiana RALPH M. HALL, Texas
JOHN BARROW, Georgia FRED UPTON, Michigan
HENRY A. WAXMAN, California ED WHITFIELD, Kentucky
EDWARD J. MARKEY, Massachusetts JOHN SHIMKUS, Illinois
ALBERT R. WYNN, Maryland JOHN B. SHADEGG, Arizona
MIKE DOYLE, Pennsylvania CHARLES W. ``CHIP'' PICKERING,
JANE HARMAN, California Mississippi
TOM ALLEN, Maine STEVE BUYER, Indiana
CHARLES A. GONZALEZ, Texas MARY BONO, California
JAY INSLEE, Washington GREG WALDEN, Oregon
TAMMY BALDWIN, Wisconsin MIKE ROGERS, Michigan
MIKE ROSS, Arkansas SUE WILKINS MYRICK, North Carolina
DARLENE HOOLEY, Oregon JOHN SULLIVAN, Oklahoma
ANTHONY D. WEINER, New York MICHAEL C. BURGESS, Texas
JIM MATHESON, Utah JOE BARTON, Texas (ex officio)
JOHN D. DINGELL, Michigan (ex
officio)
------
Professional Staff
Sue Sheridan, Chief Counsel
Laura Vaught, Policy Coordinator
David McCarthy, Minority Chief Counsel
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
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 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. 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.
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.
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.
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.
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
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 CO\2\ 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 CO\2\ 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 CO\2\ fit into the atmospheric mix? I'm told
all CO\2\ is only 0.038 percent of atmospheric gases;
2. How does the CO\2\ from fossil fuel combustion fit into
the total annual CO\2\ 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 percent of all
fossil fuel use in the United States, we would only reduce
CO\2\ 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
CO\2\ 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, CO\2\ 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 CO\2\
emissions restrains economic output, jeopardizes economic
growth, and eliminates people's jobs.
Now there are three camps in the political discussion about
capping CO\2\. 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 CO\2\
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
Geosciences, 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 extent. 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.
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
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 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
Nino 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 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.
[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 Nino 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.
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, CO\2\, 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 CO\2\
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 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
increase 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 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 large-scale 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 models. 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?
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 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.
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 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:]
[GRAPHIC] [TIFF OMITTED] T7414.001
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
Kyoto-like. 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 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.
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 CO\2\ 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 CO\2\ 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 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.
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 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 as CO\2\ 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
CO\2\ 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 CO\2\ 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
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, CO\2\ 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
temperature 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 CO\2\ emissions right now. The only way I see
something like that happening is a massive nuclear power----
Mr. Burgess. But if we did?
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 four-person 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.
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?
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, 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.
CO\2\ warms the planet. What would the mean temperatures of the
planet be if there were no CO\2\ 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 CO\2\.
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.
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, CO\2\, 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 pre-
industrial 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 CO\2\. 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 CO\2\ 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 CO\2\. And CO\2\, 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 CO\2\, and
if we have double the amount CO\2\, 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 CO\2\, 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.'' 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 CO\2\ 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 CO\2\. 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 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.
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 CO\2\ in the atmosphere, you
have a bank with water vapors. The water vapor increases as we
increase CO\2\. 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.
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 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.
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 CO\2\ 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.
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
CO\2\ 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 CO\2\ 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.
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:
<bullet> Average global surface temperature has warmed
over the last 50 years, with a greater rate of 0.17'C (0.3'F)
per decade since 1979.
<bullet> Global average sea surface temperatures have
warmed 0.35'C (0.6'F) since 1979.
<bullet> Global sea level has risen at a rate of 0.31 cm
per year since 1993.
<bullet> Arctic summer sea-ice extents and Northern
Hemisphere snow cover have decreased, and permafrost layer
temperatures have increased since the 1980's.
<bullet> 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, continental-average
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:
<bullet> 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.
<bullet> By the middle of the 21st century the choice of
scenario becomes more important.
<bullet> Continued greenhouse gas emissions at or above
current rates would very likely induce many changes in climate
much larger than those observed to date.
<bullet> Snow cover and sea ice coverage are projected to
contract.
<bullet> It is very likely that hot extremes, heat waves,
and heavy precipitation events will continue to become more
frequent.
<bullet> Even if greenhouse gas concentrations were to be
stabilized, anthropogenic warming and sea level will continue
for centuries.
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