<DOC>
[107th Congress House Hearings]
[From the U.S. Government Printing Office via GPO Access]
[DOCID: f:81495.wais]
THE U.S. NATIONAL CLIMATE CHANGE ASSESSMENT: DO THE CLIMATE MODELS
PROJECT A USEFUL PICTURE OF REGIONAL CLIMATE?
=======================================================================
HEARING
before the
SUBCOMMITTEE ON
OVERSIGHT AND INVESTIGATIONS
of the
COMMITTEE ON ENERGY AND COMMERCE
HOUSE OF REPRESENTATIVES
ONE HUNDRED SEVENTH CONGRESS
SECOND SESSION
__________
JULY 25, 2002
__________
Serial No. 107-117
__________
Printed for the use of the Committee on Energy and Commerce
Available via the World Wide Web: http://www.access.gpo.gov/congress/
house
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COMMITTEE ON ENERGY AND COMMERCE
W.J. ``BILLY'' TAUZIN, Louisiana, Chairman
MICHAEL BILIRAKIS, Florida JOHN D. DINGELL, Michigan
JOE BARTON, Texas HENRY A. WAXMAN, California
FRED UPTON, Michigan EDWARD J. MARKEY, Massachusetts
CLIFF STEARNS, Florida RALPH M. HALL, Texas
PAUL E. GILLMOR, Ohio RICK BOUCHER, Virginia
JAMES C. GREENWOOD, Pennsylvania EDOLPHUS TOWNS, New York
CHRISTOPHER COX, California FRANK PALLONE, Jr., New Jersey
NATHAN DEAL, Georgia SHERROD BROWN, Ohio
RICHARD BURR, North Carolina BART GORDON, Tennessee
ED WHITFIELD, Kentucky PETER DEUTSCH, Florida
GREG GANSKE, Iowa BOBBY L. RUSH, Illinois
CHARLIE NORWOOD, Georgia ANNA G. ESHOO, California
BARBARA CUBIN, Wyoming BART STUPAK, Michigan
JOHN SHIMKUS, Illinois ELIOT L. ENGEL, New York
HEATHER WILSON, New Mexico TOM SAWYER, Ohio
JOHN B. SHADEGG, Arizona ALBERT R. WYNN, Maryland
CHARLES ``CHIP'' PICKERING, GENE GREEN, Texas
Mississippi KAREN McCARTHY, Missouri
VITO FOSSELLA, New York TED STRICKLAND, Ohio
ROY BLUNT, Missouri DIANA DeGETTE, Colorado
TOM DAVIS, Virginia THOMAS M. BARRETT, Wisconsin
ED BRYANT, Tennessee BILL LUTHER, Minnesota
ROBERT L. EHRLICH, Jr., Maryland LOIS CAPPS, California
STEVE BUYER, Indiana MICHAEL F. DOYLE, Pennsylvania
GEORGE RADANOVICH, California CHRISTOPHER JOHN, Louisiana
CHARLES F. BASS, New Hampshire JANE HARMAN, California
JOSEPH R. PITTS, Pennsylvania
MARY BONO, California
GREG WALDEN, Oregon
LEE TERRY, Nebraska
ERNIE FLETCHER, Kentucky
David V. Marventano, Staff Director
James D. Barnette, General Counsel
Reid P.F. Stuntz, Minority Staff Director and Chief Counsel
______
Subcommittee on Oversight and Investigations
JAMES C. GREENWOOD, Pennsylvania, Chairman
MICHAEL BILIRAKIS, Florida PETER DEUTSCH, Florida
CLIFF STEARNS, Florida BART STUPAK, Michigan
PAUL E. GILLMOR, Ohio TED STRICKLAND, Ohio
RICHARD BURR, North Carolina DIANA DeGETTE, Colorado
ED WHITFIELD, Kentucky CHRISTOPHER JOHN, Louisiana
Vice Chairman BOBBY L. RUSH, Illinois
CHARLES F. BASS, New Hampshire JOHN D. DINGELL, Michigan,
ERNIE FLETCHER, Kentucky (Ex Officio)
W.J. ``BILLY'' TAUZIN, Louisiana
(Ex Officio)
(ii)
C O N T E N T S
__________
Page
Testimony of:
Janetos, Anthony C., Senior Fellow, The H. John Heinz III
Center for Science, Economics, and the Environment......... 5
Karl, Thomas R., Director, National Climatic Data Center..... 13
Lashof, Daniel A., Deputy Director, Climate Center, Natural
Resources Defense Council.................................. 27
Michaels, Patrick J., Professor and Virginia State
Climatologist, Department of Environmental Sciences,
University of Virginia..................................... 50
O'Brien, James J., Director, Center for Ocean-Atmospheric
Prediction Studies, Florida State University............... 34
Pielke, Roger A., Sr., President-elect, American Association
of State Climatologists, Colorado State Climatologist, and
Professor, Department of Atmospheric Science, Colorado
State University........................................... 42
(iii)
THE U.S. NATIONAL CLIMATE CHANGE ASSESSMENT: DO THE CLIMATE MODELS
PROJECT A USEFUL PICTURE OF REGIONAL CLIMATE?
----------
THURSDAY, JULY 25, 2002
House of Representatives,
Committee on Energy and Commerce,
Subcommittee on Oversight and Investigations,
Washington, DC.
The subcommittee met, pursuant to notice, at 9:30 a.m., in
room 2322, Rayburn House Office Building, James C. Greenwood
(chairman) presiding.
Members present: Representatives Greenwood, Deutsch, and
Fletcher.
Staff present: Peter Spencer, professional staff; Yong
Choe, legislative clerk; and Michael L. Goo, minority counsel.
Mr. Greenwood. On the record. Good morning. The meeting
will come to order, and let me begin by apologizing to our
witnesses and to our guests for the tardiness. It was actually
unavoidable.
The Chair recognizes himself for 5 minutes for an opening
statement.
Good morning, and welcome. This morning we will stand at
the intersection of science, policymaking, and public concern
about climate change to consider if an influential report
provides the guidance necessary to navigate this often
confusing and uncertain territory.
At issue is the use of climate models to create the
regional climate change scenarios that frame the discussion in
what is called in shorthand the U.S. National Assessment on
Climate Change.
The national report about this assessment, prepared by
scientists and researchers under a Federal advisory committee,
known as the National Assessment Synthesis Team, two co-chairs
of which are before us today, seeks to provide policymakers and
the public with plausible pictures of regional climate 50 to
100 years from now under the impact of global warming.
Now let me note as we head into this a couple of points
about my perspective. First, I tend to agree with the view
expressed in some of the testimony we will hear this morning
that there are some reasonable mitigation--there are some
reasonable mitigation measures and other policy strategies we
can take to address climate change risks, and that these do not
depend upon the scientific dispute before us. Indeed, this
dispute should not be used to avoid decisions on such policies.
Of course, there continues to be much debate about some of
these policy decisions, how much can or should we do, when
should we do it, and the debate has engaged many members of the
Energy and Commerce Committee on both sides of the aisle.
The hearing today, though it will help inform the debate,
is not the appropriate forum to conduct that debate, which
would only distract us from the important questions before us
this morning.
Second, this is not to suggest we should glide over
questions of science and the scientific validity of the tools
and methods used to drive understanding of inherently science
based issues. We need sound science to inform our decisions and
to ensure our actions in the name of science--to ensure that
our actions in the name of science aren't misguided because we
were more confident than we should have been.
So we begin today with a straightforward question: Do the
climate models project a useful picture of regional climate? We
have asked our panelists today, all scientists and all quite
familiar with the controversies about climate, climate
variability and impacts, and the national assessment, to
comment on this and to speak to the role and suitability of the
models used in this report.
In the U.S. Climate Action Report released to the United
Nations this past May, reference to the National Assessment
discussed the use of the models this way. ``Use of these models
is not meant to imply that they provide accurate predictions of
the scientific changes in climate that will occur over the next
100 years. Rather, the models are considered plausible
projections of potential changes for the 21st century.''
Two initial questions come to my mind when I read this, and
I hope the witnesses can assist us in answering these questions
this morning. The first has to do with the plausibility of the
picture painted by the models. This is basically a science
question, which I am sure the experts here can sort out for
this layman, and this is how reliable are the predictions of
plausible regional outcomes, given the admitted limitations of
the modeling, and what would this mean for the usefulness of
the report? And given the wide variation in the projections'
results that oppose each other in one area but are similar in
others, is it reasonable to rely upon them to take specific
actions or to adopt specific policies?
This appears to be a thoughtful report, and I believe the
authors sincerely attempted to work through describing some of
the uncertainty for policymakers and the public. Was it
sufficient? How did the models work in the full picture here?
The second question relates to the problem of communicating
the uncertainty. The reference above makes a rather nuanced
description of predictions versus the projections. Yet the New
York Times which reported the Climate Action Report's reference
to the Assessment wrote this back in May: ``The report says the
United States will be substantially changed in the next few
decades, very likely seeing the disruptions of snow-fed water
supplies, more stifling heat waves, and the permanent
disappearance of Rocky Mountain meadows and coastal marshes.''
Was this the message the authors want the public to take
away? We must come to grips with the fact that a scientific
assessment such as this is more than an academic exercise read
by the few who can grasp all the complexities. It is a document
meant to guide us, policymakers and the public, though
complicated policy intersections where we really rely on
science as much as we can.
The stakes here are as high as any could be, the very
inhabitability of our planet. The cost of reducing the stakes
is also high. For both of these reasons, the reliability of our
predictive models must be high indeed.
I thank the witnesses again, especially those who have
traveled so far to testify this morning. I now recognize the
ranking member, Mr. Deutsch of Florida, for his opening
statement.
Mr. Deutsch. Thank you, Mr. Chairman. I believe this is our
third hearing regarding climate change. Just a few comments
representing south Florida. At some level I think we are
probably more affected by potential climate change than
anywhere in the country, and there won't be much of south
Florida left.
The sea level of Florida's Gulf Coast has risen sharply, up
as many as 8 inches over the last 100 years, and more sharply
over the last few decades and, as people are well aware, higher
sea levels can mean beach erosion, threatening homes and
communities, coral reef erosion, and more intense and damaging
storms and hurricanes.
Florida's average temperature since the Sixties has also
risen. Higher temperatures mean more heat related illnesses,
decreasing air quality. Both higher sea levels and higher
temperatures will seriously affect obviously greater areas,
including our Everglades restoration efforts, and can severely
affect our tourism industry. Florida is a community where
environment and the economy effectively are one.
I look forward to the testimony. I am just somewhat
disappointed. As you are well aware, this is our last week in
session, and we were in session until about two o'clock
yesterday evening, and I don't really expect many members to be
here this morning, which is unfortunate. But I am sure their
staffs can review the record. I yield back.
Mr. Greenwood. Thank you, ranking member.
[Additional statements submitted for the record follow:]
Prepared Statement of Hon. Paul E. Gillmor, a Representative in
Congress from the State of Ohio
Mr. Chairman, I wanted to quickly add my comments regarding climate
change. In particular, I appreciate the opportunity to learn about the
role of climate models as well as to discuss whether the U.S. National
Climate Change Assessment should continue to serve as a benchmark with
regard to potential impacts of climate change on our environment and
human health.
I also look forward to hearing from our panel of witnesses. I
should also point out that in a time when the U.S. economy is so
dependent upon energy, and so much of our energy is derived from fossil
fuels, reducing emissions poses major challenges. Like many Members, I
feel that rushing to judgement on these matters could be very costly,
both socially and economically. In an effort to produce sound
environmental policy while maintaining steady economic growth, I am
hopeful that we will continue to review scientific information about
climate change to evaluate potential economic and strategic impacts of
a warmer, and perhaps more variable, climate.
Again, I thank the Chairman and yield back my time.
______
Prepared Statement of Hon. W.J. ``Billy'' Tauzin, Chairman, Committee
on Energy and Commerce
Thank you Chairman Greenwood. And, let me also thank you for
putting together what promises to be an informative hearing--one that
gets to the heart of a controversy that has lingered over this national
assessment for a couple of years now.
I can tell you I have a pretty good appreciation, as does everybody
from the Bayou State, for what Mother Nature can do to us. And she sure
does remind us in a variety of ways.
The U.S. National Assessment also reminds us about the ways our
country may someday be affected by climate change--whether that climate
change is natural or influenced by man. But it also conveys some
pictures of the future that, as we'll hear this morning, might not be
quite what they seem.
I look forward to learning more about the use of climate models in
the assessment. I'm curious to know whether the inherent uncertainties
in these models--uncertainties I understand to be widely accepted
within the science community--were properly accounted for when using
the models to sketch out the climate change scenarios in this report.
I'm also curious to learn whether, if they weren't properly
accounted for, whether they undercut what was otherwise a well-
intentioned, and potentially useful report. Did the models, in effect,
send all this good research focusing on the wrong impacts?
Nobody has perfect foresight. But we do have scientific assessments
and other tools to help us reduce the odds that our decisions about the
future are more than wild guesses. What troubles me, and I believe many
Members who must confront difficult and potentially expensive decisions
about climate change, is that something that is asserted to be sound
science, is not as sound as it was portrayed to be. This creates false
assurance where perhaps knowledge of what we don't know would be more
useful to guard against risks. It also threatens to undercut public
trust in the science policymakers use to make their decisions.
We have before us today a distinguished panel of experts who can
explain the role of climate modeling in this assessment. They can put
matters in proper perspective for us. We have them all here on one
panel, too, so that perhaps we can generate some discussion to get
further to the bottom of this controversy.
I thank you again, Mr. Chairman and yield back the remainder of my
time.
Mr. Greenwood. It is the case that we were in session until
two o'clock this morning. It is not an excuse, just an
explanation for why some of the members may come in a little
later than otherwise.
To the panelists, you are aware that the House--this
committee is holding an investigative hearing, and I think you
have been informed that when we hold investigative hearings, it
is our custom to take our testimony under oath. Do any of you
object to giving your testimony under oath? Okay.
Not normally for this kind of hearing but for other
hearings we must inform you that you are entitled to have a
counsel, have a lawyer represent you, be represented by
counsel. Do any of you wish to be represented by counsel? Okay.
In that case, if you would all stand and raise your right hand,
I will give you the oath.
[Witnesses sworn.]
Mr. Greenwood. Thank you. You are under oath. Let me
introduce the panel. From my left to right, Dr. Anthony C.
Janetos, Senior Fellow with the H. John Heinz Center for
Science, Economics, and the Environment; Dr. Thomas Karl,
Director of the National Climatic Data Center in North
Carolina; Dr. Daniel Lashof, Deputy Director of the Climate
Center, the Natural Resources Defense Counsel; Dr. James J.
O'Brien, Director of the Center for Ocean-Atmospheric
Prediction Studies at Florida State University; Dr. Roger
Pielke, Sr., President-Elect of the American Association of
State Climatologists, Colorado State Climatologist, and
Professor in the Department of Atmospheric Science at Colorado
State University; and Dr. Patrick J. Michaels, Professor and
Virginia State Climatologist, Department of Environmental
Sciences, University of Virginia.
We welcome you all. Thank you for helping us this morning.
Dr. Janetos, we will begin with you. You are recognized for 5
minutes to give your testimony.
TESTIMONY OF ANTHONY C. JANETOS, SENIOR FELLOW, THE H. JOHN
HEINZ III CENTER FOR SCIENCE, ECONOMICS, AND THE ENVIRONMENT;
THOMAS R. KARL, DIRECTOR, NATIONAL CLIMATIC DATA CENTER; DANIEL
A. LASHOF, DEPUTY DIRECTOR, CLIMATE CENTER, NATURAL RESOURCES
DEFENSE COUNCIL; JAMES J. O'BRIEN, DIRECTOR, CENTER FOR OCEAN-
ATMOSPHERIC PREDICTION STUDIES, FLORIDA STATE UNIVERSITY; ROGER
A. PIELKE, SR., PRESIDENT-ELECT, AMERICAN ASSOCIATION OF STATE
CLIMATOLOGISTS, COLORADO STATE CLIMATOLOGIST, AND PROFESSOR,
DEPARTMENT OF ATMOSPHERIC SCIENCE, COLORADO STATE UNIVERSITY;
AND PATRICK J. MICHAELS, PROFESSOR AND VIRGINIA STATE
CLIMATOLOGIST, DEPARTMENT OF ENVIRONMENTAL SCIENCES, UNIVERSITY
OF VIRGINIA
Mr. Janetos. Thank you, Mr. Chairman. I am pleased to have
this opportunity to address this committee on the topic of ``Do
the Climate Models Project a Useful Picture of Climate
Change?''
Mr. Greenwood. You might want to pull the microphone. It is
fairly directional, if you could--Thank you.
Mr. Janetos. Thanks. The US National Assessment, ``Climate
Change Impacts on the United States: The Potential Consequences
of Climate Variability and Change'' was released in November of
2000, following an extensive series of peer reviews and public
comment.
This first document, the overview, was followed about a
month later by the release of the foundation, a much more
extensive, fully documented background document that lays out
all of the analytical detail and data that were used in the
National Assessment. We believe that the National Assessment is
an extensive synthesis of the best available scientific
information on this important topic.
There are three questions about climate change that have
dominated discussions. How much climate change is going to
occur? What will happen as a result? What can countries do
about it? There are obviously heated opinions about each of
these, but the issues are real, and it is critical to
understand the underlying scientific knowledge about each if
sound decisions are to be made. The national assessment report
focuses on the second of these questions: What will happen as a
result?
A national assessment of the potential impacts of climate
change was called for in the 1990 legislation that established
the U.S. Global Change Research Program. For several years,
that program focused on developing the basic scientific
knowledge that the international scientific assessment process,
overseen by the IPCC, depends on.
That scientific research provided increasing evidence that
change in the climate system is, in fact, occurring. It has
become increasingly clear that there is a need to understand
what is at stake for natural resources and human well-being in
the U.S.
In response to this need, in 1998 Dr. John Gibbons, then
Science Advisor to the President, requested the USGCRP to
undertake a national assessment originally called for in the
legislation. He directed--asked the program to investigate a
series of important questions:
What are the current environmental stresses and issues for
the United States that form a backdrop for additional impacts
of climate change?
How might climate change and variability exacerbate or
ameliorate existing problems?
What are the priority research and information needs that
can better prepare policymakers for making wise decisions
related to climate change and variability? What information and
answers to what key questions could help decisionmakers make
better informed decisions about risk, priorities, and
responses? What are the potential obstacles to information
transfer?
What research is most important to complete over the short
term and over the long term?
What coping options exist that can build resilience to
current environmental stresses, and also possibly lessen the
impacts of climate change? How can we simultaneously build
resilience and flexibility for the various sectors considering
both the short and long term implications?
What natural resource planning and management options make
most sense in the face of future uncertainty?
What choices are available for improving our ability to
adapt to climate change and variability, and what are the
consequences of those choices?
A variety of efforts emerged in response to Dr. Gibbons'
quite daunting charge. Over 20 workshops were held around the
country, involving academics, business people representing a
range of industries including manufacturing, power generation
and tourism, and people who work closely on the land and in the
water, including resource managers, ranchers, farmers,
foresters and fishermen.
Each workshop identified a range of issues of concern to
stakeholders in those regions, many of them quite unrelated to
climate change per se. Most were followed by the initiation of
scientific, university led regional studies.
In addition to these kinds of bottom-up efforts, it was
decided that it was also necessary to create a national level
synthesis of what is known about the potential for climate
impacts for the U.S. as a whole, addressing the issues
identified in the regional workshops and national studies.
This synthesis, obviously, needed to build on the work that
had begun to emerge from the subsequent regional and national
studies, but also to draw on the existing scientific literature
and analyses done with the most up to date ecological and
hydrological models and data that could be obtained.
The National Assessment Synthesis Team, the NAST, was
established by the NSF as an independent committee under the
Federal Advisory Committee Act specifically in order to carry
out this second step. It was made up of experts from academia,
industry, government laboratories, and non-governmental
organizations, and in order to ensure its openness and
independence, all meetings of the NAST were open to the public,
all documents discussed in its meetings are available through
the NSF, as are all the review comments received and the
responses to them.
This is perhaps out of the ordinary for a scientific study,
but most scientific studies do not focus on issues of such
broad and deep implications for the country, and about which
there is such heated debate.
Our first action was to publish a plan for the conduct of
the national synthesis. In addition, five issues, agriculture,
water, forests, human health, and coastal and marine systems,
were selected to be topics for national studies. Carrying out
this plan was, obviously, a major undertaking, with the two
reports that I mentioned earlier as the two primary national
outputs.
Both of those national outputs have been through extensive
review. At the end of 1999 two rounds of technical peer review
were undertaken, and during the spring of 2000 an additional
review by about 20 experts who had been outside of the
assessment process was undertaken. Over 300 sets of comments
were received from scientists in universities, industry, NGO's,
and government labs. The responses to external comments have
been described in comprehensive review memorandums.
The final stage of that process, a 60-day public comment
period specifically requested by Congress, after which final
revisions were then completed. The report was submitted to the
President so that it could be transmitted to Congress, as
called for in the original legislation. Hundreds of additional
comments were received during the public comment period, each
of which was responded to.
In order to ensure that we did our job well, an oversight
panel was also established through the offices of the
President's Council of Advisors on Science and Technology. That
oversight panel was chaired by Dr. Peter Raven, Director of the
Missouri Botanical Garden and former Home Secretary of the
National Academy of Sciences, and Dr. Mario Molina, Professor
of Atmospheric Chemistry at MIT and recent Nobel prize winner
for his research on stratospheric ozone depletion. Its
membership, like the NAST's, was also drawn from academia,
industry, and the NGO's. It reviewed and approved the plans for
the assessment. It reviewed each draft of the report, and
reviewed the response of our synthesis team to all comments.
It is important to realize that the national assessment
does not attempt to predict exactly what the future will hold
for the U.S. It examined the potential implications of two
primary climate scenarios, each based on the same assumptions
about future global emissions of greenhouse gases, the same
assumptions that has been used as one of many emission
scenarios examined by the IPCC.
The two climate scenarios were based on output from two
different global climate models used in the IPCC assessments,
and we believe they were clearly within the range of global--
The results were clearly within the range of the global annual
average temperature changes shown by many such models, one of
them near the low end of this range and one near the high end.
Both also exhibit warming trends for the U.S. that are larger
than the global average, but this is not surprising.
In addition to the two primary models from the Canadian
Climate Centre and the Hadley Centre, in different parts of the
national process results from climate models developed at the
National Center for Atmospheric Research, NOAA's Geophysical
Fluid Dynamics Laboratory, NASA's Goddard Institute for Space
Studies, and the Max Planck Institute were also used in various
aspects of the assessment.
The NAST was aware of the scientific issues surrounding the
use of regional results form any general circulation models. In
the analyses done with the climate models' regional outputs,
simulations from the models were used to adjust historically
observed data using methods that had already been peer reviewed
in other studies, in order to depict scenarios that had
sufficient regional richness for analysis. So, in fact, we did
not use, for the most part, the raw data from the GCMs, but
used that to adjust historical data.
In addition to models, the National Assessment used two
other ways to think about potential future climate. Many groups
involved in our process used historical climate records to
evaluate sensitivities of regions, sectors and natural
resources, the climate variability and extremes that have in
fact occurred during the 20th Century.
Looking at real historical climate events, their impacts,
and how people have adapted, gives valuable insights into
potential future impacts that complement those provided by
model projects. In addition, the assessment used sensitivity
analyses, some of which ask how and by how much the climate
would have to change to result in impacts on particular regions
and sectors.
These climate scenarios describe significantly different
futures that are scientifically plausible, given our current
understanding of how the climate system operates. That
understanding will, no doubt, continue to improve. As
importantly, they describe separate baselines for analysis of
how natural ecosystems, agriculture, water supplies, etcetera,
might change as a result.
In order to investigate such changes, the potential impacts
of changes in the physical climate system, the report relies on
up to date ecological and natural resource models, on empirical
observations from the literature, on investigations of how
those systems have responded to climate variability that has
been observed over the past century, and on the accumulated
scientific knowledge that is available about the sensitivity of
natural resources to climate, and about how the regions of the
U.S. have and potentially could respond.
The U.S. National Assessment presents the results for each
scenario clearly, and then takes the important additional step
of explicitly describing the NAST's scientific judgment about
the uncertainty inherent in each result. Those results that are
viewed to be robust are described in more certain terms. Those
viewed to be the result of poorly understood or unreconciled
differences between models are described in substantially more
circumspect language.
The lexicon of terms used to denote the NAST's greater or
lesser confidence is explicitly described in the beginning of
the Overview report. This helps ensure that the report does not
mask important results by thoughtlessly merging models or
overstating the scientific capability for assessing potential
impacts.
Finally, the report begins to identify possible options for
adaptation to this changing world. It does not do a complete
analysis of the costs, benefits or feasibility of these
options, however, which would be a necessary next step for
developing policies to address those issues.
Future assessments will need to consider climate change in
the context of the suite of environmental stresses that we all
face. Perhaps most importantly, our report acknowledges very
clearly that scientific uncertainties remain and that we can
expect surprises as this uncontrolled experiment with the
earth's geochemistry plays out over the coming decades.
Thank you very much.
[The prepared statement of Anthony C. Janetos follows:]
Prepared Statement of Anthony C. Janetos, Sr. Fellow, H. John Heinz III
Center for Science, Economics, and the Environment
I am pleased to have the opportunity to address the US House of
Representatives Committee on Energy and Commerce, Subcommittee on
Oversight and Investigations on the topic of ``The US National Climate
Change Assessment: Do the Climate Models Project a Useful Picture of
Climate Change?''
The US National Assessment, Climate Change Impacts on the United
States: the Potential Consequences of Climate Variability and Change
was released in November of 2000, following an extensive series of peer
reviews and public comment. This first document, the Overview, was
followed about a month later by the release of the Foundation, a much
more extensive, fully documented background document that lays out all
of the analytical detail and data that were used in the National
Assessment. The National Assessment is an extensive synthesis of the
best available scientific information on this important topic.
There are three questions about climate change that dominate
discussions of this important topic. How much climate change is going
to occur? What will happen as a result? What can countries do about it?
There are obviously heated political opinions about each of these, but
the issues are real, and it is critical to understand the underlying
scientific knowledge about each if sound decisions are to be made. The
assessment report focuses on the second of these questions.
A national assessment of the potential impacts of climate change
was called for in the 1990 legislation that established the US Global
Change Research Program (USGCRP). For several years, the research
program focused on developing the basic scientific knowledge that the
international scientific assessment process overseen by the
Intergovernmental Panel on Climate Change (IPCC) depends on. The IPCC
was jointly established by the World Meteorological Organization and
the United Nations Environmental Programme in 1988. As scientific
research has provided compelling evidence that climate change is in
fact occurring, it has become increasingly clear that there is a need
to understand what is at stake for natural resources and human well-
being in the US. In response to this need, in 1998, Dr. John H.
Gibbons, then Science Advisor to the President, requested the USGCRP to
undertake a the national assessment originally called for in the
legislation. Dr. Gibbons asked the USGCRP to investigate a series of
important questions:
<bullet> What are the current environmental stresses and issues for the
United States that form a backdrop for additional impacts of
climate change?
<bullet> How might climate change and variability exacerbate or
ameliorate existing problems?
<bullet> What are the priority research and information needs that can
better prepare policy makers for making wise decisions related
to climate change and variability? What information and answers
to what key questions could help decision-makers make better-
informed decisions about risk, priorities, and responses? What
are the potential obstacles to information transfer?
<bullet> What research is most important to complete over the short
term? Over the long term?
<bullet> What coping options exist that can build resilience to current
environmental stresses, and also possibly lessen the impacts of
climate change? How can we simultaneously build resilience and
flexibility for the various sectors considering both the short
and long-term implications?
<bullet> What natural resource planning and management options make
most sense in the face of future uncertainty?
<bullet> What choices are available for improving our ability to adapt
to climate change and variability and what are the consequences
of those choices? How can we improve contingency planning? How
can we improve criteria for land acquisition?
A variety of efforts emerged in response to Dr. Gibbons' charge.
Over twenty workshops were held around the country, involving
academics, business-people representing a range of industries including
manufacturing, power generation and tourism, and people who work
closely with land and water ecosystems including resource managers,
ranchers, farmers, foresters and fishermen. Each workshop identified a
range of issues of concern to stakeholders in those regions, many of
them quite unrelated to climate change, per se. Most workshops were
followed by the initiation of scientific, university-led regional
studies.
In addition to these kind of ``bottom-up'' efforts, it was decided
that it was also necessary to create a national-level synthesis of what
is known about the potential for climate impacts for the US as a whole,
addressing the issues identified in the regional workshops and national
studies. This synthesis obviously needed to build on the work that had
begun to emerge from the subsequent regional and national studies, but
also to draw on the existing scientific literature and analyses done
with the most up-to-date ecological and hydrological models and data
that could be obtained. The National Assessment Synthesis Team (NAST)
was established by the National Science Foundation as an independent
committee under the Federal Advisory Committee Act (FACA) specifically
in order to carry out this second step. This committee was made up of
experts from academia, industry, government laboratories, and non-
governmental organizations (NGO's) (membership list is Attachment 1).
In order to ensure openness and independence, all meetings of the NAST
were open to the public, all documents discussed in its meetings are
available through the National Science Foundation, as are all the
review comments already received and responses to them. This is perhaps
out of the ordinary for a scientific study; but most scientific studies
do not focus on issues of such broad and deep implications for American
society, and about which there is such heated rhetoric.
The NAST's first action was to publish a plan for the conduct of
the national synthesis. In addition, five issues (agriculture, water,
forests, health, and coastal and marine systems), out of the many
identified, were selected to be topics for national studies. Carrying
out this plan was a major undertaking. The end result has been the
production of a comprehensive two-volume national assessment report.
The ``Foundation'' volume is more than 600 pages long, with more than
200 figures and tables, with analyses of the five national sectors, and
9 regions that together cover the entire US. It is extensively
referenced, and a commitment was made that all sources used in its
preparation were to be open and publicly available. The ``Overview''
volume is about 150 pages long, written in a style that is more
accessible to the lay public, and summarizes the Foundation in a way
that is understandable and informative, and which we are confident is
scientifically sound. Both documents have already been through
extensive review. At the end of 1999, two rounds of technical peer
review were undertaken, and during the spring of 2000, an additional
review by about 20 experts outside the assessment process was
undertaken. Over 300 sets of comments have been received from
scientists in universities, industry, NGO's, and government
laboratories. The responses to all external comments have been
described in comprehensive review memorandums. The final stage of the
process, a 60 day public comment period specifically requested by
Congress, after which final revisions was then completed, and the
report was submitted to the President so that it could be transmitted
to Congress, as called for in the original legislation. Hundreds of
additional comments were received during the public comment period,
each of which was responded to.
In order to ensure that the NAST carried out its charge well, an
oversight panel was also established through the offices of the
President's Council of Advisors on Science and Technology (membership
list is Attachment 2). The oversight panel was chaired by Dr. Peter
Raven, Director of the Missouri Botanical Garden and former Home
Secretary of the National Academy of Sciences, and Dr. Mario Molina,
Professor of Atmospheric Chemistry at MIT, and recent Nobel-prize
winner for his research on stratospheric ozone depletion. Its
membership, like the NAST's, was also drawn from academia, industry,
and NGO's. It reviewed and approved the plans for the assessment,
reviewed each draft of the report, and reviewed the response of the
NAST to all comments.
What have been the results of this extraordinarily open process?
What assumptions drive the analysis? What conclusions have been
reached?
It is important to realize that the national assessment does not
attempt to predict exactly what the future will hold for the US. It
examined the potential implications of two primary climate scenarios,
each based on the same assumptions about future ``business as usual''
global emissions of greenhouse gases that the IPCC has used for many of
its analyses. The two climate scenarios were based on output from two
different global climate models used in the IPCC assessment. They are
clearly within the range of global annual average temperature changes
shown by many such models, one near the low and one near the high end
of the range. Both exhibit warming trends for the US that are larger
than the global average. This is not surprising. For many years, one of
the most robust results of global climate models has been that greater
warming is expected in more northerly latitudes, and that land surfaces
are expected to warm more than the global average. We have used
assumptions that are entirely consistent with those used by the IPCC.
In addition to the two primary models from the Canadian Climate Centre
and the Hadley Centre, results from climate models developed at the
National Center for Atmospheric Research, NOAA's Geophysical Fluid
Dynamics Laboratory, NASA's Goddard Institute for Space Studies, and
the Max Planck Institute were also used in various aspects of the
Assessment.
The NAST was aware of the scientific issues surrounding the use of
regional results from any general circulation models. In the analyses
done with the climate models' regional outputs, simulations from the
models were used to adjust historically observed data in order using
methods that had already been peer-reviewed in other studies, in order
to depict scenarios that had sufficient regional richness for analysis.
In addition to models, the Assessment used two other ways to think
about potential future climate. First, it used historical climate
records to evaluate sensitivities of regions and sectors to climate
variability and extremes that have occurred in the 20th century.
Looking at real historical climate events, their impacts, and how
people have adapted, gives valuable insights into potential future
impacts that complement those provided by model projections. In
addition, the Assessment used sensitivity analyses, which ask how, and
how much, the climate would have to change to bring major impacts on
particular regions and sectors.
These climate scenarios describe significantly different futures
that are scientifically plausible, given our current understanding of
how the climate system operates. As importantly, they describe separate
baselines for analysis of how natural ecosystems, agriculture, water
supplies, etc. might change as a result. In order to investigate such
changes, i.e. the potential impacts of climate changes, the report
relies on up-to-date models, on empirical observations from the
literature, on investigations of how these systems have responded to
climate variability that has been observed over the past century in the
US, and on the accumulated scientific knowledge that is available about
the sensitivities of resources to climate, and about how the regions of
the US have and potentially could respond.
One additional important point about the scenarios should be
mentioned. The report does not average the results of models that
disagree; it explicitly avoids doing so. The best example of this is in
the analysis of potential changes in precipitation, where the two
models used to create the scenarios give quite different results for
some areas of the US. We have chosen to highlight these differences and
explain that regional-scale precipitation projections are much more
uncertain compared with temperature, rather than attempting to merge
the results or guess which is more likely. The knowledge that the
direction of precipitation change in some areas is quite uncertain is
valuable for planning purposes, and clearly represents and important
research challenge. There is however, consistency among models and
observations on other aspects of precipitation changes. For example,
both models and observations show an increase in the proportion of
precipitation derived from heavy and extreme events as the climate
warms. So, both types of information are pertinent to help with the
identification of potential coping actions. In this respect, the report
follows the procedure that the IPCC itself uses for its global impacts
reports, each of which examines the potential impacts for entire
continents.
The US national assessment presents the results for each scenario
clearly, and then takes the important additional step of explicitly
describing the NAST's scientific judgment about the uncertainty
inherent in each result. Those results that are viewed to be robust are
described in more certain terms; those viewed to be the result of
poorly understood or unreconciled differences between models are
described in more circumspect language. The lexicon of terms used to
denote the NAST's greater or lesser confidence is explicitly described
in the beginning of the Overview report. This helps ensure that the
report does not mask important results by thoughtlessly merging models,
or overstating the scientific capability for assessing potential
impacts. Finally, the report begins to identify possible options for
adaptation to this changing world. It does not do a complete analysis
of the costs, benefits, or feasibility of these options however, which
is a necessary next step for developing policies to address these
issues.
The report's key findings present important observations for all
Americans:
1. Increased warming. Assuming continued growth in world greenhouse
gas emissions, the climate models used in this Assessment project that
temperatures in the US will rise 5-10 deg.F (3-5 deg.C) on average in
the next 100 years.
2. Differing regional impacts. Climate change will vary widely
across the US. Temperature increases will vary somewhat from one region
to the next. Heavy and extreme precipitation events are likely to
become more frequent, yet some regions will get drier. The potential
impacts of climate change will also vary widely across the nation.
3. Vulnerable ecosystems. Many ecosystems are highly vulnerable to
the projected rate and magnitude of climate change. A few, such as
alpine meadows in the Rocky Mountains and some barrier islands, are
likely to disappear entirely in some areas. Others, such as forests of
the Southeast, are likely to experience major species shifts or break
up. The goods and services lost through the disappearance or
fragmentation of certain ecosystems are likely to be costly or
impossible to replace.
4. Widespread water concerns. Water is an issue in every region,
but the nature of the vulnerabilities varies, with different nuances in
each. Drought is an important concern in every region. Floods and water
quality are concerns in many regions. Snow-pack changes are especially
important in the West, Pacific Northwest, and Alaska.
5. Secure food supply. At the national level, the agriculture
sector is likely to be able to adapt to climate change. Overall, US
crop productivity is very likely to increase over the next few decades,
but the gains will not be uniform across the nation. Falling prices and
competitive pressures are very likely to stress some farmers, while
benefiting consumers.
6. Near-term increase in forest growth. Forest productivity is
likely to increase over the next several decades in some areas as trees
respond to higher carbon dioxide levels. Over the longer term, changes
in larger-scale processes such as fire, insects, droughts, and disease
will possibly decrease forest productivity. In addition, climate change
is likely to cause long-term shifts in forest species, such as sugar
maples moving north out of the US.
7. Increased damage in coastal and permafrost areas. Climate change
and the resulting rise in sea level are likely to exacerbate threats to
buildings, roads, power lines, and other infrastructure in climatically
sensitive places. For example, infrastructure damage is related to
permafrost melting in Alaska, and to sea-level rise and storm surge in
low-lying coastal areas.
8. Adaptation determines health outcomes. A range of negative
health impacts is possible from climate change, but adaptation is
likely to help protect much of the US population. Maintaining our
nation's public health and community infrastructure, from water
treatment systems to emergency shelters, will be important for
minimizing the impacts of water-borne diseases, heat stress, air
pollution, extreme weather events, and diseases transmitted by insects,
ticks, and rodents.
9. Other stresses magnified by climate change. Climate change will
very likely magnify the cumulative impacts of other stresses, such as
air and water pollution and habitat destruction due to human
development patterns. For some systems, such as coral reefs, the
combined effects of climate change and other stresses are very likely
to exceed a critical threshold, bringing large, possibly irreversible
impacts.
10. Uncertainties remain and surprises are expected. Significant
uncertainties remain in the science underlying regional climate changes
and their impacts. Further research would improve understanding and our
ability to project societal and ecosystem impacts, and provide the
public with additional useful information about options for adaptation.
However, it is likely that some aspects and impacts of climate change
will be totally unanticipated as complex systems respond to ongoing
climate change in unforeseeable ways.
Given these findings it is clear that climate impacts will vary
widely across the Nation, as one would expect for a country as large
and ecologically diverse as the US. Natural ecosystems appear to be
highly vulnerable to climate changes of the magnitude and rate which
appear to be likely; some ecosystems surprisingly so. The potential
impacts on water resources are an important issue in every region
examined, although the nature of the concern is very different for the
mountainous West than for the East. The potential for drought is a
concern across the country. The nation's food supply appears secure,
but there are very likely to be regional gains and losses for farmers,
leading to a more complex picture on a region-by-region basis. Forests
are likely to grow more rapidly for a few decades because of increasing
carbon dioxide concentrations in the atmosphere, but it is unclear
whether those trends will be maintained as the climate system itself
changes, leading to other disturbances such as fire and pest outbreaks.
However, the climate change itself will, over time, lead to shifts in
the tree species in each region of the country, some of them
potentially quite profound. Coastal areas in many parts of the US and
the permafrost regions of Alaska are already experiencing disruptions
from sea-level rise and recent regional warming; these trends are
likely to accelerate. Climate change will very likely magnify the
cumulative impacts of other environmental stresses about which people
are already concerned, such as air and water pollution, and habitat
destruction due to development patterns. There are clearly links
between human health, current climate, and air pollution. The future
vulnerability of the US population to the health impacts of climate
change depends on our capacity to adapt to potential adverse changes.
Many of these adaptive responses are desirable from a public health
perspective irrespective of climate change. Future assessments need to
consider climate change in the context of the suite of environmental
stresses that we all face. Perhaps most importantly, the report
acknowledges very clearly that scientific uncertainties remain, and
that we can expect surprises as this uncontrolled experiment with the
Earth's geochemistry plays out over the coming decades.
Attachment 1
national assessment synthesis team members
Jerry M. Melillo, Co-chair, Ecosystems Center, Marine Biological
Laboratory; Anthony Janetos, Co-chair, World Resources Institute;
Thomas R. Karl, Co-chair, NOAA, National Climatic Data Center; Robert
Corell (from January 2000), American Meteorological Society and Harvard
University; Eric J. Barron, Pennsylvania State University; Virginia
Burkett, USGS, National Wetlands Research Center; Thomas F. Cecich,
Glaxo Wellcome, Inc.; Katharine Jacobs, Arizona Department of Water
Resources; Linda Joyce USDA Forest Service; Barbara Miller, World Bank;
M. Granger Morgan, Carnegie Mellon University; Edward A. Parson (until
January 2000), Harvard University; Richard G. Richels, EPRI; and David
S. Schimel, National Center for Atmospheric Research. Additional Lead
Authors; David Easterling (NOAA National Climatic Data Center); Lynne
Carter (National Assessment Coordination Office); Benjamin Felzer
(National Center for Atmospheric Research); John Field (University of
Washington); Paul Grabhorn (Grabhorn Studio); Susan J. Hassol (Aspen
Global Change Institute); Michael MacCracken (National Assessment
Coordination Office); Joel Smith (Stratus Consulting); and Melissa
Taylor (National Assessment Coordination Office).
Attachment 2
independent review board of the president's committee of advisers on
science and technology (pcast)
Peter Raven, Co-chair, Missouri Botanical Garden and PCAST; Mario
Molina, Co-chair, MIT and PCAST; Burton Richter, Stanford University;
Linda Fisher, Monsanto; Kathryn Fuller, World Wildlife Fund; John
Gibbons, National Academy of Engineering; Marcia McNutt, Monterey Bay
Aquarium Research Institute; Sally Ride, University of California San
Diego and PCAST; William Schlesinger, Duke University; James Gustave
Speth, Yale University; and Robert White, University Corporation for
Atmospheric Research, and Washington, Advisory Group.
Mr. Greenwood. Thank you, Dr. Janetos. Thank you very much
for your testimony.
Dr. Karl.
TESTIMONY OF THOMAS R. KARL
Mr. Karl. Good morning, Chairman Greenwood and members of
the subcommittee. I was one of the three co-chairs of the
report of the National Assessment Team. As Dr. Janetos has
indicated, the synthesis team was comprised of scientists and
other specialists from universities, industries, governments
and non-governmental organizations.
The National Assessment reports are not policy positions or
official statements of the U.S. Government. Rather, they were
produced by a selected set of members of the scientific
community and offered to the government for its consideration.
I am very pleased to have this opportunity to present the
testimony regarding the basis for the scenarios of the 21st
century climate used in the National Assessment.
The purpose of the National Assessment was to synthesize,
evaluate, and report on what we knew about the consequences of
climate variability and change for the United States in the
21st Century.
The National Assessment was our first attempt to generate
climate scenarios for various regions and sectors across the
United States. It relied on a number of techniques to develop
climate scenarios for the 21st Century, including historical
data to examine the continuation of trends, the recurrence of
past climate extremes, climate model simulations in attempt to
provide plausible scenarios for how the future climate may
change, and sensitivity analysis to explore the resilience of
societal and ecology systems to climate fluctuations and
change.
Numerous climate models were used in the National
Assessment, but the two primary models were selected on the
basis of a set of objective criteria that I have described in
some detail in my written testimony. Today, if the assessment
were repeated with similar criteria, results of several other
models would be included.
As I described in some detail in my written testimony, in a
comparison of the models used in the National Assessment with
observations and other models indicates that the two primary
model used in the National Assessment reflected the state of
scientific understanding when the National Assessment was
conducted between 1997 and 2000.
This had important consequences. For example, the amount of
summertime precipitation expected over much of the contiguous
USA as the climate warmed was quite uncertain and required the
use of several what-if analyses to assess potential impacts.
Other projected changes were less uncertain, like increased
temperatures everywhere during all seasons. So the impact
analysis could focus on the magnitude of the warming as opposed
to the sign of the projected changes.
Interestingly, despite the fact that global models do not
agree well in the sign of summer precipitation changes, in
general climate models indicate that as greenhouse gases
increase, on average more intense precipitation will occur.
Indeed, observations in the USA and elsewhere reflect this
today. That is, a greater proportion of the total precipitation
occurs in heavy and very heavy precipitation events.
This attribute of precipitation change was another scenario
considered by the sectorial and regional impact and adaptation
assessments. Given the many differences among models, wherever
feasible the National Assessment relied on model simulations to
assess impacts to the greatest extent possible. A particularly
noteworthy example comes from the Great Lakes region. Results
from 10 models were used to assess changes in Great Lake levels
during the 21st Century.
In conclusion, the National Assessment we conducted on the
impact of climate change had significant limitations, but was
an important first step. Quite clearly, more needs to be done,
and such efforts can provide more effective decision support
tools, help frame adaptation mitigation measures to avoid the
potential risk and harm of climate change, and maximize the
potential benefits.
I want to thank the chairman for allowing me the
opportunity to describe the rationale used in the National
Assessment to develop the climate scenarios for the 21st
Century. I would be happy to answer any questions later. Thank
you.
[The prepared statement of Thomas R. Karl follows:]
Prepared Statement of Thomas R. Karl, Director, National Climatic Data
Center, National Environmental Satellite, Data, and Information
Services, National Oceanic and Atmospheric Administration
introduction
Good morning, Chairman Greenwood and members of the Subcommittee. I
am Thomas R. Karl, Director of NOAA's National Climatic Data Center. I
was invited to appear today because I was one of the three Co-Chairs of
the Report of the National Assessment Synthesis Team (NAST).
I would like to begin by emphasizing that the reports of the
National Assessment Synthesis Team are not a product of the U.S.
Government, and they do not represent government policy. In fact, they
have sometimes been quite controversial. The National Assessment
Synthesis Team is an advisory committee chartered under the Federal
Advisory Committee Act. The NAST reports are not policy positions or
official statements of the U.S. government. Rather, they were produced
by selected members of the scientific community and offered to the
government for its consideration.
The Synthesis Team was comprised of individuals drawn from
governments, universities, industry, and non-governmental organizations
that had responsibility for broad oversight of the National Assessment
entitled ``Climate Change Impacts on the United States--The Potential
Consequences of Climate Variability and Change.'' The purpose of the
Assessment was to synthesize, evaluate, and report on what we presently
know--and don't know--about the potential consequences of climate
variability and change for the United States in the 21st century. It
attempted to review climate vulnerabilities of particular regions of
the nation and of particular sectors, and sought to provide a number of
adaptation measures to reduce the risk, and maximize the potential
benefits and opportunities of climate change, whatever its cause. The
National Assessment was conducted from 1997 to 2000 and was our first
attempt to generate climate scenarios for various regions and sectors
across the United States, which turned out to be a very challenging
task. I am very pleased to have this opportunity to present testimony
regarding the basis for the scenarios of 21st century climate used in
the National Assessment.
As a basis for the National Assessment, and in the context of the
uncertainties inherent in looking forward 100 years, the NAST pursued a
three-pronged approach to considering how much the climate may change.
The three approaches involved use of: (1) historical data to examine
the continuation of trends or recurrence of past climatic extremes; (2)
comprehensive, state-of-the-science (though still with significant
limitations), model simulations to provide plausible scenarios for how
the future climate may change; and (3) sensitivity analyses that can be
used to explore the resilience of societal and ecological systems to
climatic fluctuations and change. Of particular interest for this
hearing is the second of these approaches, and that is where I will
focus my remarks. As a pretext however, I note that the National
Assessment rests on a combination of these approaches.
developing model-based scenarios for the 21st century
Projecting changes in factors that influence climate
Because future trends in fossil fuel use and other human activities
are uncertain, the Intergovernmental Panel on Climate Change (IPCC) has
developed a set of scenarios for how the 21st century may evolve. These
scenarios consider a wide range of possibilities for changes in
population, economic growth, technological development, improvements in
energy efficiency and the like. The two primary climate scenarios used
in the National Assessment were based on a mid-range emission scenario
used in the second IPCC report. This scenario assumes no major changes
in policies to limit greenhouse gas emissions. Other important
assumptions in the scenario are that by the year 2100:
<bullet> world population is projected to nearly double to about 11
billion people;
<bullet> the global economy is projected to continue to grow at about
the average rate it has been growing, reaching more than ten
times its present size;
<bullet> increased use of fossil fuels are projected to triple
CO<INF>2</INF> emissions and raise sulfur dioxide emissions,
resulting in atmospheric CO<INF>2</INF> concentrations of just
over 700 parts per million; and
<bullet> total energy produced each year from non-fossil sources such
as wind, solar, biomass, hydroelectric, and nuclear are
projected to increase to more than ten times its current
amount, providing more than 40% of the world's energy, rather
than the current 10%.
There are a number of other important factors besides fossil fuel
emissions that cause climate to change and vary. These were not part of
the scenario used to drive climate change in the two primary models
used in the National Assessment, because at the time of the National
Assessment these simulations were not available. Figure 1 depicts the
magnitude of these other climate forcings that were omitted from the
emission scenario. Clearly, the two largest forcings are those related
to increases in greenhouse gases and aerosols, both included in the two
primary models used in the National Assessment. The addition of other
forcings are an important consideration for improvement of future
assessments, for example the
role of black carbon aerosols, and a more thorough treatment of
land vegetative feedback effects which become quite important on local
and regional space scales compared to global scales, e.g., the urban
heat island.
Which models to use?
The NAST developed a set of guidelines to aid in narrowing the set
of primary model simulations to be considered for use by the Assessment
teams. This helped ensure a degree of consistency across the broad
number of research teams participating in the Assessment. These
guidelines included various aspects related to the structure of the
model itself, the character of the simulations, and the availability of
the needed results. Specifically this meant that the models must, to
the greatest extent possible:
<bullet> be coupled atmosphere-ocean general circulation models that
include comprehensive representations of the atmosphere,
oceans, and land surface, and the key feedbacks affecting the
simulation of climate and climate change;
<bullet> simulate the evolution of the climate through time from at
least as early as the start of the detailed historical record
in 1900 to at least as far as into the future as the year 2100
based on a well-understood scenario for changes in atmospheric
composition that takes into account time-dependent changes in
greenhouse gas and aerosol concentrations;
<bullet> provide the highest practicable spatial and temporal
resolution (roughly 200 miles [about 300 km] in longitude and
175 to 300 miles [about 275 to 425 km] in latitude over the
central US);
<bullet> include the diurnal cycle of solar radiation in order to
provide estimates of changes in minimum and maximum temperature
and to be able to represent the development of summertime
convective rainfall;
<bullet> be capable, to the extent possible, of representing
significant aspects of climate variations such as the El Nino-
Southern Oscillation cycle;
<bullet> have completed their simulations in time to be processed for
use in impact models and to be used in analyses by groups
participating in the National Assessment;
<bullet> be models that are well-understood by the modeling groups who
participated in the development of the Third Assessment Report
of the Intergovernmental Panel on Climate Change (IPCC) in
order to ensure comparability between the US efforts and those
of the international community;
<bullet> provide a capability for interfacing their results with
higher-resolution regional modeling studies (e.g., mesoscale
modeling studies using resolutions finer by a factor of 5 to
10); and
<bullet> allow for a comprehensive array of their results to be
provided openly over the World Wide Web.
Including at least the 20th century in the simulation adds the
value of comparisons between the model results and the historical
record and can be used to help initialize the deep ocean to the correct
values for the present-day period. Having results from models with
specific features, such as simulation of the daily cycle of
temperature, which is essential for use in cutting edge ecosystem
models, was important for a number of applications that the various
Assessment teams were planning.
At the time of the National Assessment only two models, the
Canadian Climate Centre Model and the United Kingdom's Hadley Centre
model, were able to satisfactorily meet these criteria. Today however,
if the Assessment were repeated with the same criteria, several more
models would meet these criteria, including modeling efforts in the
USA. Let me emphasize the importance of this, which represents another
limitation of the National Assessment. In 1998 the Climate Research
Council (which I chaired) of the National Research Council issued a
report, Capacity of U.S. Climate Modeling to Support Climate Change
Assessment Activities. While improvements in model capability have
occurred during the past four years, key findings from the CRC report
are worthy of note:
The CRC finds that the United States lags behind other
countries in its ability to model long-term climate change.
Those deficiencies limit the ability of the United States to
predict future climate states . . . Although collaboration and
free and open information and data exchange with foreign
modeling centers are critical, it is inappropriate for the
United States to rely heavily upon foreign centers to provide
high-end capabilities. There are a number of reasons for this,
including the following: (1) U.S. scientists do not necessarily
have full, open and timely access to output from European
models . . . (2) Decisions that might substantially affect the
U.S. economy might be made based upon considerations of
simulations (e.g. nested-grid runs) produced by countries with
different priorities than those of the United States.
Furthermore, the report noted, ``While leading climate models are
global in scale, their ability to represent small-scale, regionally
dependent processes . . . can currently only be depicted in them using
high-resolution, nested grids. It is reasonable to assume that foreign
modeling centers will implement such nested grids to most realistically
simulate processes on domains over their respective countries which may
not focus on or even include the United States.''
The use of observations
Observations were an essential part of developing climate scenarios
for the 21st century in the National Assessment. Reliance on model
simulations provides only a limited opportunity to investigate the
consequences of climate variability and change. To minimize this
limitation, in the National Assessment the historical record was used
to help determine regional and sector specific sensitivities to climate
changes and variations of differing, but contextual realistic changes.
The observations were also used to understand how the models
simulated present and past climate (see Figure 2), and to correct a
number of model biases. While climate models have shown significant
improvement over recent decades, and the models used in the National
Assessment were among the world's best, there were a number of
shortcomings in applying the models to study potential regional-scale
consequences of climate change. This is a fundamental limitation to the
results of the National Assessment, and should be kept in mind. In the
National Assessment, several methods were used in an attempt to address
these problems. Most importantly, the output from the primary models
(the Hadley and Canadian) for temperature and precipitation were passed
through a set of standardization processing algorithms to re-calibrate
the model simulations with the observations. This is especially
important in areas of complex terrain such as mountainous regions of
the West were model resolution was insufficient to adequately resolve
detailed small-scale climate characteristics. The processing procedure
accounted for at least some of the shortcomings and biases in the
models. So, the model scenario results used in the impact assessments
were often adjusted to remove the systematic differences with
observations that were present in the model simulations. Such a
procedure is similar to what is now being implemented in daily weather
forecasting, where actual model projections are not used, but rather
the historical statistical and dynamical relationships between the
weather model forecasts and actual observations are used to generate
local weather forecasts. This adjustment process is fully described in
the foundation report of the National Assessment.
In addition, some of the regional teams applied other types of
``down-scaling'' techniques to the climate model results in order to
derive estimates of changes occurring at a finer spatial resolution.
One such technique has been to use the global climate model results as
boundary conditions for mesoscale models that cover some particular
region (e.g., the West Coast with its Sierra Nevada and Cascade
Mountains). These models are able to represent important processes and
mountain ranges on finer scales than do global climate models. These
small-scale simulations however, have not been as well tested as global
models and are very computer intensive. It has not yet been possible to
apply the techniques nationally or for the entire 20th or 21st
centuries. With the rapid advances in computing power expected in the
future, this approach should become more feasible for future
assessments. To overcome the computational limitations of mesoscale
models, some of the Assessment Teams developed and tested empirically
based statistical techniques to estimate changes at finer scales than
the global climate models, and these efforts are discussed in the
various regional assessment reports. These techniques have the
important advantage of being based on observed weather and climate
relationships, but have the shortcoming of assuming that the
relationships prevailing today will not change in the future.
Another type of tool developed for use in the sensitivity analyses
were statistical models and weather generators used to calculate
probabilities of unusual weather and climate events. These models
enabled impact analysts to compose ``what if'' questions for strings of
weather and climate events that could be important to their specific
sector or region. Other approaches focused on using a variety of other
types of observational data.
evaluation of the models
Among the tests that have been used to evaluate the skill of
climate models have been evaluations of climate model output to
simulate present weather and climate, the cycle of the seasons,
climatic variations over the past 20 years (the time period when the
most complete data sets are available), climatic changes over the past
100 to 150 years during which the world has warmed, and climatic
conditions for periods in the geological past when the climate was
quite different than at present.
There are so many kinds of evaluations that can be made it is not
possible to provide one test to ascertain the appropriateness of any
model for climate impact assessments. For example, models may be
expected to reproduce the past climate for hemispheric and global
averages on century time-scales because much of the climate noise due
to seasonal to inter-annual climate variability tends to be less
important. This includes many of the important climate oscillations
such as the El Nino, the North Atlantic Oscillation, the Pacific
Decadal Oscillation, and others. Because models generally replicate the
chaotic behavior of the natural climate, the climate models simulate
their own year-by-year climates and they will not produce the precise
timing of these events to match the observations. On the other hand,
the climate models may be expected to reproduce the statistical
distribution of these events. So, to compare models to observations it
is important to be able to average out these natural variations that
can have very large impacts for given regions in specific years. For
this reason in the National Assessment comparisons of the model
simulations with observations on regional and subregional levels were
made by averaging over multiple decades or longer.
In conducting climate model evaluations it is tempting to prefer
those models where the simulations most closely match the observations,
but several complications must be accounted for in such
intercomparisons. First, there are inherent errors and biases in our
observational data. Models, even if they are provided perfect forcing
scenarios and had perfect chemistry, physics and biology, should not be
expected to perfectly match imperfect observations. By cross comparing
observations from differing data sets and observing systems we can
roughly estimate some of the observational errors and biases. Second,
because of the chaotic nature of the climate, we cannot expect to match
the year-by-year or decade-by-decade fluctuations in temperature that
have been observed during the 20th century. Third, the particular model
simulations used in the National Assessment did not include
consideration of all of the effects of human-induced and naturally-
induced changes that are likely to have influenced the climate,
including changes in stratospheric and tropospheric ozone, volcanic
eruptions, solar variability, and changes in land cover (and associated
changes relating to biomass burning, dust generation, etc.). Finally,
while it is desirable for model simulations not to have significant
biases in representing the present climate, having a model that more
accurately reproduces the present and past climate does not necessarily
mean that projections of changes in climate developed using such a
model would provide more accurate projections of climate change than
models that do not give as accurate simulations. This can be the case
for at least two reasons. First, what matters most for simulation of
changes in future climate is proper treatment of the feedbacks that
contribute to amplifying or limiting the changes, and accurate
representation of the 20th century does not guarantee this will be the
case. Second, because projected changes are calculated by taking
differences between perturbed and unperturbed cases, the effects of at
least some of the systematic biases present in a model simulation of
the present climate can be eliminated. While potential nonlinearities
and thresholds make it unlikely that all biases can be removed in this
manner, it is also possible that the projected changes calculated by
such a model could turn out to be more accurate than simulations with a
model that provided a better match to the 20th century climate.
Recognizing these many limitations, evaluation of the simulations
from the Canadian and Hadley models are briefly summarized here to give
an indication of the kinds of tests climate scientists have completed
to assess the general adequacy of the models for use in assessing the
impacts of climate change and variability. As depicted in Figure 2 both
primary models capture the rise in global temperature since the late
1970s, but do not do as well in reproducing decadal variations. The
question of how these two models compare to other climate models,
several of which were not available at the time of the National
Assessment, is addressed in Figure 3. Note that the scaling factor
required to match in the increase in temperature during the 20th
century for all models is close to one, except for the Canadian Climate
Model which is somewhat less than one, reflecting the relatively high
sensitivity of this model to increases in greenhouse gases, although
the scaling factor in a later version of the model (CGCM2 in Figure 3)
is closer to one. It is also noteworthy that the later version of the
Hadley Centre Model very closely reproduces the rate of 20th century
warming when a more complete set of forcings, indirect sulfate forcing
and tropospheric ozone, is added to the model. Another test of a
model's ability to reproduce 20th Century global temperatures is to
compare the annual temperatures generated by the models with the
observations. To assess relative skill, errors can be compared to
projections based on temperature persistence. That is, always
predicting the annual mean temperature to be equal to the longer-term
mean over the length of the averaging period centered on either side of
the prediction year. Figure 4 shows some results of such a test for
averaging periods from 10 to 50 years. This is a difficult test for a
model to show skill because the persistence forecast actually includes
information about the annual mean temperature both before and after the
``prediction year.'' In all cases the model simulations have smaller
errors than the persistence based projection, indicating significant
skill.
So, analyses at the global scale for the two primary models used in
the National Assessment indicate that there is general agreement with
the observed long-term trend in temperature over the 20th century, but
the Canadian Climate Model is significantly more sensitive to
greenhouse gases compared to the Hadley Centre Model, and may be
thought of as the ``hotter'' of the two models. This higher climate
sensitivity of the Canadian model may be due to projection an earlier
melting of the Arctic sea ice than the Hadley model. It is not yet
clear how rapidly this melting may take place.
The question as to whether the Canadian Climate Model is an outlier
can be addressed in Figure 5 where the global warming rate has been
plotted for various models with similar forcings of greenhouse gases
and sulfate aerosols. The Canadian Climate Model is seen to have a
relatively high sensitivity to increases in greenhouse gases compared
to other models, but its sensitivity is quite comparable to a model not
used in the National Assessment, NOAA's Geophysical Fluid Dynamics
Laboratory R15 model. So, although the Canadian model does appear to be
one of the more sensitive models to increases in greenhouse gases, it
is not an outlier. By comparison the Hadley Centre model appears to
have moderate sensitivity to increases in greenhouse gases.
The National Assessment was not performed on global space scales,
so it is important to understand the differences between model
simulations and observations on regional scales. As part of a long-term
Climate Model Intercomparison Project (CMIP2), Dr. Benjamin Santer of
the Lawrence Livermore National Laboratory has recently compared
results from a number of climate models related to their ability to
reproduce the annual mean precipitation and the annual cycle of
precipitation across North America. The results of this study, which
included the two primary models used in the National Assessment, are
depicted in Figures 6 and 7. The figure shows the correlation between
the patterns of the model output and the observations (the y-axis)
along with a measure of the differences in actual precipitation (the x-
axis). If there were no errors in our observing capability, a perfect
model would reproduce the observations exactly and have perfect
correlation with the observations, the difference between any observed
model grid point and observational grid point would be zero, and it
would appear as a point in the far upper left corner of the plot. By
comparing two different observational data sets we can get an estimate
of the errors in the observations and this has been done in Figures 6
and 7 by comparing two different 20-year climatologies over North
America by two different research groups. So, no model should be
expected to be in the quadrant of the diagram to the upper left of the
less than perfect observational data sets. It is clear in Figures 6 and
7 that the Hadley Centre model used in the National Assessment
reproduces the observations better than all other models, while the
Canadian Climate Centre Model does not do as well, but is by no means
an outlier.
Although the changes in global scale features and the regional
simulations of precipitation of the two primary models are seen to be
rather typical of other models, there are important issues on regional
scales that suggest that significant uncertainties remain in our
ability to effectively use these models for impact assessments. For
example, problems with the way these climate models simulate ENSO
variability suggest that the projected pattern of changes may not be
definitive. Also, as illustrated by the different projections of
changes in summer precipitation used in the National Assessment in the
Southeast, there are often several processes that can contribute to the
pattern of change. The same process can lead to different projections
of changes when imposed on a slightly different base state of the
climate. For example, the proportion of the oceans that are frozen
versus liquid, the amount of snow cover extent, the dryness of the
ground surface, the strength of North Atlantic deep water circulation,
etc., all can play important roles. In addition, the different
representations of land surface processes, clouds, sea-ice dynamics,
horizontal and vertical resolution, as well as many other factors
included in different climate models, can have an important impact on
projections of changes in regional precipitation. This dependence
occurs because precipitation, unlike atmospheric dynamics, is a highly
regionalized feature of the climate, depending on the interaction of
many processes, many of which require a set of model parameterizations.
Given these many limitations, in the National Assessment the model
simulations were viewed as projections not as predictions. The
significance of this distinction can be seen in the following quote
from the recently-released Climate Action Report 2002: ``Use of these
model results is not meant to imply that they provide accurate
predictions of the specific changes in climate that will occur over the
next hundred years. Rather, the models are considered to provide
plausible projections of potential changes for the 21st century. For
some aspects of climate, the model results differ. For example, some
models, including the Canadian model [used in this Assessment] project
more extensive and frequent drought in the United States, while others,
including the Hadley model [the other model used in the Assessment] do
not. As a result, the Canadian model suggests a hotter and drier
Southeast during the 21st century, while the Hadley model suggests
warmer and wetter conditions. Where such differences arise, the primary
model scenarios provide two plausible, but different alternatives.''
how were the model projections used?
They model projections were used as indications of the types of
consequences that might result. For example, as evident in Figure 2,
although the emissions scenarios are the same for the Canadian and
Hadley simulations, the Canadian model scenario projects more rapid
global warming than does the Hadley model scenario. This greater
warming in the Canadian model scenario occurs in part because the
Hadley model scenario projects a wetter climate at both the national
and global scales, and in part because the Canadian model scenario
projects a more rapid melting of Arctic sea ice than the Hadley model
scenario.
Recognizing that all model results are plausible projections rather
than specific quantitative predictions, the consistency of the
temperature projections of the primary models used for the National
Assessment were assessed in a broader context. Figure 8 illustrates how
this strategy was used. It is apparent that virtually all models
consistently show a much greater than the global average warming over
the US during winter and a greater than average warming during summer,
except for Alaska. So, in the National Assessment all the scenarios of
temperature change related to increased temperatures and the increases
were often as larger or larger than the global mean temperature
increase.
Although there are many similarities in the projected changes of
temperature amongst the many climate models considered by the IPCC
(Figure 8), this is not true of precipitation changes. In the National
Assessment the Hadley Centre model often projected significantly wetter
conditions compared to the Canadian model, but this variation is
typical of our present state of understanding as depicted in Figure 9.
Only during winter is there a consistent pattern of a small increase of
precipitation among most of the climate models; by contrast during
summer there is not much agreement about the sign or magnitude of the
precipitation change, except for a general tendency for more
precipitation in the high latitudes of North America. The
inconsistencies among all the models with respect to summertime mid-
latitude North American precipitation (Figure 9) were reflected in the
two scenarios used in the National Assessment, ensuring consideration
of a range of possible outcomes. To address this range of possible
outcomes a number of ``what if'' scenarios were developed and used in
the National Assessment. For example, in the West, although both models
in the National Assessment projected precipitation increases, a ``what-
if'' scenario of less precipitation was used to broaden the assessment
of possible climate impacts, vulnerabilities, and adaptation measures.
Interestingly, despite the fact that the global climate models do
not agree well on the sign of summer precipitation changes, virtually
all climate models indicate that as greenhouse gases increase more
intense precipitation events will occur over many areas. Indeed,
observations reflect this today in many mid and high latitude land
areas where data are available for such an assessment. For these
reasons and the fact an increase in precipitation intensity can
effectively be argued from simple thermodynamic considerations, this
attribute of precipitation change was an important scenario considered
by the sectoral and regional impact and adaptation assessments.
It should also be noted in the National Assessment, due to the
nature of the differences among various models, wherever feasible other
model simulations were used to assess possible impacts. A particularly
noteworthy example comes from the Great Lakes Region. Results from ten
models were used to simulate changes in Great Lake levels during the
21st century. All but one of the models suggested lower Lake levels. So
a combination of the primary models, other climate models, and
observations were instrumental in identifying key climate impacts and
vulnerabilities for the 21st Century.
future assessments
To build confidence in the projections used for future climate
assessments, much remains to be done. Further improvements in climate
models are needed, especially in the representations of clouds,
aerosols (and their interactions with clouds), sea ice, hydrology,
ocean currents, regional orography, and land surface characteristics.
Improving projections of the potential changes in atmospheric
concentrations of greenhouse gases, aerosols and land use is important.
Climate model simulations based on these revised emissions forecasts
should provide improved sets of information for assessing climate
impacts. In addition to having results from more models available,
ensembles of simulations from several model runs are needed so that the
statistical significance of the projections can be more fully examined.
As part of these efforts, it is important to develop greater
understanding of how the climate system works (e.g., of the role of
atmosphere-ocean interactions and cloud feedbacks), to refine model
resolution, to more completely incorporate existing understanding of
particular processes into climate models, to more thoroughly test model
improvements, and to augment computational and personnel resources in
order to conduct and more fully analyze a wider variety of model
simulations, including mesoscale modeling studies.
While much remains to be done that will take time, much can also be
done in the next few years that can substantially improve the set of
products and tools available to assess climate impacts. For example, an
intensified analysis program is needed to provide greater understanding
of the changes and the reasons why they occur. New efforts to
incorporate the interactive effects of changes in land use and
vegetation in meso-scale and global models will help in understanding
local and regional climate change and variability. A better
understanding of the changes in weather patterns and extremes in
relation to global changes is important. Improved efforts that combine
analysis of the model results with the insights available from analysis
of historical climatology and past weather patterns needs to be a
priority. Regional climate scenarios can also be developed using a
combination of climate model output and dynamical reasoning. More use
of mesoscale models is important because they can provide higher
resolution of spatial conditions.
In the National Assessment, we were able to consider only one set
of emission scenarios rather than a range of emission scenarios. For
the future, the actual emissions of greenhouse gases and aerosols could
be different than the baseline used. Changing the emissions scenario
would give increasingly divergent climate scenarios as the time horizon
expanded. This would likely become important beyond the next few
decades as different emission scenarios are not likely to significantly
affect climate scenarios because of the relatively slow response of the
global climate and energy systems, and because a large portion of the
change will be due to past emissions.
As recently stated by the Assistant Secretary for Oceans and
Atmosphere, Dr. Mahoney, the highest and best use of the scientific
information developed in the combined United States Global Climate
Research Program (USGCRP) and the President's Climate Change Research
Initiative (CCRI) could be the development of comparative information
that will assist decision makers, stakeholders and the general public
in debating and selecting optimal strategies for mitigating global
change, while maintaining sound economic and energy security conditions
in the United States and throughout the world. Significant progress in
developing and applying science-based decision tools during the next 1
to 3 years must be a key goal of the combined USGCRP and CCRI program.
Examples of analyses expected to be completed during this time period
that would improve our nations ability to conduct a subsequent National
Assessment include:
<bullet> Long-term global climate model projections (e.g., up to the
year 2100) for a wide selection of potential mitigation
strategies, to evaluate the expected range of outcomes for the
different strategies.
<bullet> Detailed analyses of variations from defined ``base''
strategies, to investigate the importance of specific factors,
and to search for strategies with optimum effectiveness.
<bullet> Linked climate change and ecosystem change analyses for
several suggested strategies, to search for optimum benefits.
<bullet> Detailed analyses of the outcomes that would be expected from
application of the wide selection of energy conservation
technologies, and carbon sequestration strategies, currently
being investigated by the National Climate Change Technology
Initiative
summary
The National Assessment conducted from 1997-2000 was a first step.
It relied on a number of techniques to develop climate scenarios for
the 21st century including: historical data to examine the continuation
of trends or recurrence of past climatic extremes; climate model
simulations in an attempt to provide plausible scenarios for how the
future climate may change; and sensitivity analyses to explore the
resilience of societal and ecological systems to climatic fluctuations
and change. Numerous climate models were used in the National
Assessment, but the two primary models were selected on the basis of a
set of objective criteria. Today, if the Assessment were repeated with
the similar criteria, results of several other models would be
included.
Intercomparison of the models used in the National Assessment with
observations and other models indicates that the two primary models
used in the National Assessment reflects the state of scientific
understanding approximately 2-3 years ago. This had important
consequences. For example, the amount of summertime precipitation
expected over much of the contiguous USA as the climate warmed was
quite uncertain and required use of several ``what if'' analyses to
assess potential impacts. Other projected changes were more certain,
like increased temperatures everywhere, during all seasons, and impact
analyses could focus on the magnitude as opposed to the sign of
projected change.
In conclusion, the National Assessment we conducted on the impact
of climate variability and change had significant limitations, but was
a first step. Quite clearly, more needs to be done and such efforts
will provide more effective decision support tools to help frame
adaptation and mitigation measures to avoid the risk and harm of
climate change and maximize its potential benefits.
It is important to note a major recommendation in the National
Research Council's recent analysis (2001) of some key questions related
to Climate Change Science. Specifically, that report states that ``the
details of the regional and local climate change consequent to an
overall level of global climate change'' requires further
understanding. The uncertainties that surfaced in generating scenarios
for the National Assessment was clearly in our minds when we made this
recommendation.
Resolving these uncertainties will be essential to understanding
the scope of any climate change impact. Quite clearly, more needs to be
done and such efforts will provide more effective decision support
tools to help frame adaptation and mitigation measures to avoid the
potential risk and harm of climate change and maximize its potential
benefits.
[GRAPHIC] [TIFF OMITTED] 81495.001
Figure 1 Global, annual-mean radiative forcings (Wm<SUP>-2</SUP>)
due to a number of agents for the period from pre-industrial (1750) to
present (about 2000). In the National Assessment forcings due to
greenhouse gases (the first column) and sulfate (the fourth column)
were the only forcings used in the emission scenario. The height of the
vertical bars represent the best estimate value, while its absence
denotes no best estimate is possible. The vertical line about the
rectangular bar with ``x'' provides an estimate of the uncertainty
range. (From IPCC, 2001)
[GRAPHIC] [TIFF OMITTED] 81495.002
Figure 2 Trends of global temperature from observations, the United
Kingdom's Hadley Center Global Climate Model, and the Canadian Climate
Center's Global Climate Model. Trends have been smoothed to remove
year-to-year high frequency variations.
[GRAPHIC] [TIFF OMITTED] 81495.003
Figure 3 Estimates of the ``scaling factors'' by which the
amplitude of several model-simulated signals must be multiplied to
reproduce the corresponding change in the observed record. The vertical
lines represent the 5-95% confidence interval due to internal natural
variability. The models used in the National Assessment were the HadCM2
with greenhouse gases and sulfur (GS) and the CGCM1 with greenhouse
gases and sulfur (GS). Abbreviations: GS includes greenhouse and
sulfate forcing and GSIO includes also includes the indirect effect of
sulfate aerosol forcing plus tropospheric ozone forcing. See IPCC(2001)
for details.
[GRAPHIC] [TIFF OMITTED] 81495.004
Figure 4 A comparison of the ability of the Hadley Center and
Canadian Climate Center coupled global climate models used in the
National Assessment to simulate the 20th century global climate
compared with using the mean temperature over various time segments to
predict year-to-year variations of global temperatures (persistence).
Standard errors less than persistence based on observations reflect
skillful simulations.
[GRAPHIC] [TIFF OMITTED] 81495.005
Figure 5 The time evolution of the globally averaged temperature
change (relative to 1961-90 mean temperature) for various climate
models forced with the emission scenarios used in the National
Assessment (see IPCC 2001 for details)
[GRAPHIC] [TIFF OMITTED] 81495.006
Figure 6 Results of a coupled ocean-atmosphere global Climate Model
Intercomparison Project (CMIP) being conducted by the Lawrence
Livermore National Laboratory. This comparison relates to the spatial
distribution of annual precipitation across North America. All models
are compared to the ``Xie/Arkin'' observational data set. The
difference between two differing observation-based data sets reflect
observational uncertainties, so we would not expect any model to
skillfully exceed these differences. All models are evaluated on the
basis of pattern correlations with the observations and the relative
differences of annual precipitation integrated across all model grid
points in North America. The Hadley Center climate model used in the
National Assessment is shown with an ``*'' and the Canadian Climate
Center is shown with a ``#'' symbol.
[GRAPHIC] [TIFF OMITTED] 81495.007
Figure 7 Similar to Figure 6 except the results relate to the
ability of the models to reproduce the annual cycle of precipitation.
[GRAPHIC] [TIFF OMITTED] 81495.008
Figure 8 Analysis of coupled ocean-atmosphere inter-model
consistency in regional temperature change based on much greater (40%)
than average global warming, greater than average warming, less than
average warming, inconsistent rates of warming, or cooling for the 21st
century based on five model simulations (the Hadley and Canadian models
used in the National Assessment and three other models used in the IPCC
(2001) assessment) with 21st century increases in both greenhouse gases
and sulfates (see IPCC 2001 for details).
[GRAPHIC] [TIFF OMITTED] 81495.009
Figure 9 Similar to Figure 8 except for precipitation and a large
change represents a change in excess of 20% and a small change is
between 5 and 20% (see IPCC, 2001 for more details).
Mr. Greenwood. We thank you, Dr. Karl. Thank you so much.
Dr. Lashof.
TESTIMONY OF DANIEL A. LASHOF
Mr. Lashof. Thank you, Mr. Chairman. In summarizing my
written statement I want to try to make three points.
The first is on the general value of climate models in
looking into the future and trying to understand what is going
on.
The second is the fact that the National Assessment and the
models that underlie it were accepted not just by the Clinton
ad- ministration. They were reviewed more recently by the Bush
ad- ministration, showing very broad partisan acceptance of
those re- sults.
Third, I want to present an example of the use of climate
models to one particular study that we conducted on the effects
of global warming on trout and salmon expected in the United
States.
So why climate models? Why do we use climate models to
exam- ine the effects of global warming. The fact, Mr.
Chairman, is that we only have one earth, and it is, therefore,
impossible to conduct a standard controlled experiment where
you take one plot and apply an experimental drug or chemical to
it and another plot which is the control, which you leave
undisturbed.
We are, in fact, conducting an experiment on the earth by
adding heat trapping carbon dioxide and other greenhouse gases
to the at- mosphere, but we have no control.
So the only way we can examine what the effects of the
experi- ment that we are already engaged in would be is to have
climate models which represent the earth based on the best
available data we have from the atmosphere of the oceans, the
land surface, and mathematical descriptions of the fundamental
laws of physics. Those are run in a simulation on a computer,
and that is what we call climate modeling.
Of course, this type of simulation model is not unique to
cli- mates. It is used to simulate everything from--We test
crash cars in computers. We test fly airplanes in computers. We
test detonate
nuclear weapons in computers. In fact, it is no accident that
Law- rence Livermore National Laboratory does both climate
modeling and nuclear weapons simulations using some of the most
advanced computers in the world. So the basic idea is we are
running this experiment on the climate, and we want to know
what is going to happen, because if we wait to see everything
that happens and we don't like the results, it is too late to
change it, because these car- bon dioxide and other greenhouse
gases last in the atmosphere for a very long period of time.
So that basic approach was taken. The models were selected,
as we have heard. They are representative of what is in the
inter- national community. I just want to emphasize that, as
Tony Janetos explained, extensive peer review process, comments
by Pat Michaels and others were submitted both on the National
Assess- ment and the subsequent climate action report. They
were fully considered. Responses are fully documented in the
public record.
You can find those responses on the website of the Global
Change Research Program. I believe he is going to repeat many
of those comments today, and it is going to be difficult to
sort out all of that in this particular forum. I think it is
important to recognize that those comments were considered, and
detailed responses to them are available in the public record.
So just to make the point that the administration--the
current administration also accepted these conclusions, it is
worth noting that in 2001 the Intergovernmental Panel on
Climate Change's Synthesis Report of its Third Assessment
Report was adopted. The State Department submitted detailed
comments on the draft of this document under this
administration, and the administration fully participated in a
plenary session in September 2001 where the summary of
policymakers was adopted.
I quote extensively--or I quote not extensively, but I
quote from that report in my written testimony a few examples
of the conclu- sions from that report, which basically show
that global warming is happening, that we expect to see more
heat waves, heavy pre- cipitation events, fewer cold days.
These findings were embraced by the administration.
Let me focus a little bit more on the U.S. Climate Action
Report of 2002. This report was based upon conclusions of the
National Academy of Sciences, the IPCC climate change report
that I just mentioned, and the National Assessment that we have
been dis- cussing today. It was thoroughly vetted by this
administration and approved before its official release and
transmittal to the United Nations Framework Convention on
Climate Change.
Among the key findings of the Climate Action Report are
that, for example, rather than, ``Rather than simply
considering the po- tential influences of arbitrary changes in
temperature, precipita- tion, and other variables, the use of
climate models scenarios en- sured that the set of climate
conditions considered was internally consistent and physically
plausible.'' That is the basic reason for using the models.
Natural ecosystems appear to be the most vulnerable to
climate change, because generally little can be done to help
them adapt to the projected rate and amount of change. Sea
level rise at mid- range rates is projected to cause additional
loss of coastal wetlands,
particularly in areas where there are obstructions to landward
mi- gration, and put coastal communities at greater risk of
storm surges, especially in the southeastern United States.
Further, it found that reduced snow pack is very likely--
and this term ``very likely,'' as Dr. Janetos explained, is a
specific term used to represent that this is a robust finding--
to alter the timing and amount of water supplies, potentially
exacerbating water short- ages, particularly throughout the
western United States. Current water management practices
cannot be successfully altered or modified.
So I think the clear conclusion from these findings is that
global warming does pose a very severe threat to public health
and wel- fare in the United States Let me just finish by
summarizing the example of a recent study that NRDC and
Defenders of Wildlife re- leased in May that used some of the
climate models, updated versions of two of the models used in
the National Assessment plus a third model to project the
likely effects of global warming on a particularly valued sport
fish, trout and salmon, in the United States.
We found, based on this analysis in this report, which I
would ask to be included in the record, that at the regional
level the loss of trout habitat in the northeast and southwest
could be particu- larly severe, although losses are also
expected in the southeast and Rocky Mountain regions.
For example, in Pennsylvania we found that losses of trout
habi- tat are projected to be 6 to 11 percent by 2030, 22 to 28
percent by 2060, and 33 to 44 percent by 2090, assuming
continued emis- sion increases of heat trapping gases. At the
national level the re- sults are loss of 5 to 17 percent by
2030, 14 to 34 percent by 2060.
This range of results are based on using a variety of
climate models to look at the effects that are possible.
Providing that range is very helpful, because it gives us a
sense not of a precise pre- diction but of the likely outcomes
and the probability of those out- comes, and gives us a way to
really anticipate the types of effects we will look at if we
don't take action.
So I believe that climate models are very useful to give a
picture of what will happen. They are not precise predictions,
but they do very usefully inform us when we make decisions
about whether to control emissions of carbon dioxide and other
heat trapping gases. Though I know it is not the subject of
this hearing, I conclude from that that it is time to take
action, and it is time for mandatory lim- its on emissions of
greenhouse gases.
Thank you very much, Mr. Chairman.
[The prepared statement of Daniel A. Lashof follows:]
Prepared Statement of Daniel A. Lashof, Science Director, Climate
Center, Natural Resources Defense Council
introduction
Thank you Mr. Chairman and members of the committee. My name is
Daniel Lashof, and I am the Science Director of the Natural Resources
Defense Council's Climate Center. I appreciate the opportunity to
appear before you today.
I have been engaged in research and assessment related to global
climate change for more than 15 years. I was a reviewer of the National
Assessment Synthesis Re- port. I have also served as a Lead Author of
the Intergovernmental Panel on Cli- mate Change Special Report Land
Use, Land-Use Change, and Forestry and as a
reviewer of several reports by the panel. I have also served on the
National Re- search Council's Committee on Atmospheric Chemistry and on
the Energy Research and Development Panel of the Presidents' Committee
of Advisers on Science and Technology. Previously I served on the
Federal Advisory Committee on Options for Reducing Greenhouse Gas
Emissions from Personal Motor Vehicles. I hold a bach- elor's degree in
physics and mathematics from Harvard University and a doctorate in
Energy and Resources from the University of California at Berkeley.
The Natural Resources Defense Council (NRDC) is a national, non-
profit organiza- tion of scientists, lawyers, and environmental
specialists, dedicated to protecting public health and the environment.
Founded in 1970, NRDC serves more than 500,000 members from offices in
New York, Washington, Los Angeles, and San Francisco.
In my statement today I will address the value of using climate
models to assess the potential effects of global warming on the Untied
States and illustrate this by reviewing the results of a recent study
published by NRDC and Defenders of Wild- life on the threat posed by
global warming to trout and salmon.
experimenting on the earth's climate
Mr. Chairman, there is only one earth. It is therefore impossible
to conduct a con- trolled physical experiment that compares an
``experimental'' earth with elevated concentrations of carbon dioxide
(CO<INF>2</INF>) and other heat-trapping gases to a ``control'' earth
with an unpolluted atmosphere. Instead we are currently conducting an
un- controlled experiment in which emissions from power plants,
automobiles and other sources are adding to a thickening layer of
carbon pollution in the only atmosphere we have. The problem is that if
we don't like the consequences of this experiment it will be too late
to reverse them.
Given our one-earth experimental design, which I don't think even
Congress has the power to change, the best approach available to us is
to simulate the earth's climate system using all available data on the
composition of the atmosphere, the properties of the earth's surface,
and the conditions of the earth's oceans combined with mathematical
equations that describe the fundamental physical laws of motion and
conservation of mass and energy. This is called climate modeling.
Climate mod- els allow us to conduct non-destructive controlled
experiments: An ``experimental'' simulation with rising concentrations
of heat-trapping gases can be compared to a ``control'' simulation with
constant concentrations.
The idea of using computers to simulate physical systems with
mathematical models is not unique to climate modeling. Simulation
models are used to test-crash cars, test-fly airplanes, and test-
detonate nuclear weapons. All without the need to sweep up afterward.
If computer models were inherently useless, Boeing 777's would be
falling out of the skies. In fact, it's no accident that the Lawrence
Liver- more National Laboratory does both climate sim- ulations and
nuclear weapon simulations. And for the same reason. It is safer to run
these tests on computer models than on the real thing.
Climate models are in fact a remarkable achievement of modern
science. Despite the incredible complexity of the earth's climate
system, these models are able to simulate with high fidelity the major
processes that determine the variations in the earth's climate over
space and time: from the polar vortex to tropical monsoons and from the
depths of winter to the heat of summer and everything in between. Are
the models perfect? Of course not. Someone looking selectively for
discrepancies will always be able to find something to point to and
there will always be room for re- finements. Nevertheless, overall the
models have achieved a level of realism and ac- curacy that makes them
very useful tools. Indeed, they are the only tool we have for safely
performing experiments to investigate the effects of large-scale
pollution of the atmosphere with heat-trapping gases.
the bush administration recognizes the threat posed by global warming
The current Bush Administration has recognized the value of using
simulation models to test the potential consequences of global warming
on the United States in two recent reports that underwent extensive
interagency review. These are the 2001 Intergovernmental Panel on
Climate Change's (IPCC) Synthesis Report of the Third Assessment Report
and the U.S. Climate Action Report 2002, formally known as the Third
National Communication of the United States of America Under the United
Nations Framework Convention on Climate Change (UNFCCC).
First, in August 2001, the State Department submitted detailed
comments on the draft of the IPCC's Synthesis Report of the Third
Assessment Report. The adminis- tration carefully reviewed this report
and, while suggesting some changes and clari- fications, agreed with
all the key findings. Furthermore, they participated fully in
the IPCC Plenary meeting in September 2001, where the final IPCC TAR
Synthesis Report Summary for Policymakers (SPM) was approved in detail.
Among other things, this report concludes that:
<bullet> ``There is new and stronger evidence that most of the warming
observed over the last 50 years is attributable to human
activities.'' (Climate Change 2001: Synthesis Report, SPM, p.
5)
<bullet> ``Projections using the SRES emissions scenarios in a range of
climate models result in an increase in globally averaged
surface temperature of 1.4 to 5.8 C over the period 1990 to
2100. This is about two to ten times larger than the central
value of observed warming over the 20th century and the
projected rate of warming is very likely to be without
precedent during at least the last 10,000 years, based on
paleoclimate data.'' (SPM, p. 8)
<bullet> ``Models project that increasing atmospheric concentrations of
greenhouse gases result in changes in frequency, intensity, and
duration of extreme events, such as more hot days, heat waves,
heavy precipitation events, and fewer cold days. Many of these
projected changes would lead to increased risks of floods and
droughts in many regions, and predominantly adverse impacts on
ecological systems, socio-economic sectors, and human health.''
(SPM, p. 14)
Then, in May 2002, the administration released the U.S. Climate
Action Report 2002 and submitted it to the Secretariat of the UNFCCC.
This report is based upon conclusions by the National Academy of
Sciences, the IPCC climate change reports, and the U.S. Global Change
Research Program's U.S. National Assessment of the Potential
Consequences of Climate Variability and Change. It was thoroughly
vetted by this administration and approved before its official release.
Among the key finding of the Climate Action Report are:
<bullet> ``To provide an objective and quantitative basis for an
assessment of the potential consequences of climate change, the
U.S. National Assessment was organized around the use of
climate model scenarios that specified changes in the climate
that might be experienced across the United States (NAST 2001).
Rather than simply considering the potential influences of
arbitrary changes in temperature, precipitation, and other
variables, the use of climate model scenarios ensured that the
set of climate conditions considered was internally consistent
and physically plausible.'' (p.84)
<bullet> ``Use of these model results is not meant to imply that they
provide accurate predictions of the specific changes in climate
that will occur over the next 100 years. Rather, the models are
considered to provide plausible projections of potential
changes for the 21st century. For some aspects of climate, all
models, as well as other lines of evidence, are in agreement on
the types of changes to be expected. For example, compared to
changes during the 20th century, all climate model results
suggest that warming during the 21st century across the country
is very likely to be greater, that sea level and the heat index
are going to rise more, and that precipitation is more likely
to come in the heavier categories experienced in each region.''
(p.84)
<bullet> ``The model scenarios used in the National Assessment project
that the continuing growth in greenhouse gas emissions is
likely to lead to annual-average warming over the United States
that could be as much as several degrees Celsius (roughly 3-
9 deg.F) during the 21st century. In addition, both
precipitation and evaporation are projected to increase, and
occurrences of unusual warmth and extreme wet and dry
conditions are expectedto become more frequent.'' (p.84)
<bullet> ``Natural ecosystems appear to be the most vulnerable to
climate change because generally little can be done to help
them adapt to the projected rate and amount of change.
<bullet> ``Sea level rise at mid-range rates is projected to cause
additional loss of coastal wetlands, particularly in areas
where there are obstructions to landward migration, and put
coastal communities at greater risk of storm surges, especially
in the southeastern United States.
<bullet> ``Reduced snow-pack is very likely to alter the timing and
amount of water supplies, potentially exacerbating water
shortages, particularly throughout the western United States,
if current water management practices cannot be successfully
altered or modified.
<bullet> ``Increases in the heat index (which combines temperature and
humidity) and in the frequency of heat waves are very likely.''
(p.82).
The clear conclusion from these findings is that global warming
poses a severe threat to public health and the environment in the
United States.
trout and salmon in hot water
A study published by NRDC and Defenders of Wildlife in May on the
threat posed by global warming to trout and salmon in the United States
provides one example of the kind of analysis that can be usefully
performed using the regional results of global climate models. Because
trout and salmon are known to be intolerant of warm water, their
abundance could be threatened if future climate change warms the
streams they inhabit. I ask that this report be included in the hearing
record.
Trout and salmon are highly valued for their contribution to the
economy and culture of the United States. They thrive in the cold,
clear streams found in many mountainous and northern regions of the
country. About 10 million Americans spend an average of ten days per
year angling in streams or lakes for these fish. Dams, water
diversions, pollution, and development threaten trout and salmon, which
have already disappeared from many of the streams where they were
formerly found. Global warming poses a less visible but no less severe
threat to their survival.
To assess the magnitude of this threat we contracted with Abt
Associates to perform a new simulation study of how climate change
might affect existing habitat for four species of trout (brook,
cutthroat, rainbow, and brown) and four species of salmon (chum, pink,
coho and chinook) in streams throughout the contiguous United States.
The simulation uses the results of three different climate models,
including updated versions of the Canadian model (CGCM2) and the Hadley
Center model (HadCm3) used in the National Assessment, as well as an
Australian model (CSIRO-Mk2). The changes in air temperatures projected
by these global climate models are used to project the impact of global
warming on U.S. stream temperatures, using a new, more accurate method
to estimate the relationship between air and stream temperatures.
Interestingly, the version of the Hadley Center model used for this
study projects warming rates for the United States that are quite
similar to Canadian Model results used in the National Assessment.
Trout and salmon are particularly sensitive to increases in summer
temperature and the Hadley Model (HadCm3) projects an increase in
average July temperatures for the contiguous United States of as much
as 10 degrees Fahrenheit by 2090, assuming that emissions of heat-
trapping gases are not curtailed.
The study found that trout and salmon habitat is indeed vulnerable
to the effects of global warming. At the national level we estimate
that individual species of trout and salmon could lose 5-17 percent of
their existing habitat by the year 2030, 14-34 percent by 2060, and 21-
42 percent by 2090, based on emissions scenarios A1 and A2 from the
Intergovernmental Panel on Climate Change (IPCC), depending on the
species considered and model used. Projected effects on trout and
salmon are lower for IPCC scenarios B1 and B2, which assume that global
CO<INF>2</INF> emissions are reduced for reasons not directly related
to global warming. For these scenarios, we estimate habitat losses of
4-20 percent by 2030, 7-31 percent by 2060, and 14-36 percent by 2090,
depending on fish species and model. Of particular concern is the
number of stream locations that become unsuitable for all modeled
species (Exhibit 1).
At the regional level, loss of trout habitat in the Northeast and
the Southwest could be particularly severe, although losses are also
expected in the Southeast and Rocky Mountain regions. For example, in
Pennsylvania losses of trout habitat are projected to be 6-11 percent
by 2030, 22-28 percent by 2060, and 33-44 percent by 2090, based on the
A1 and A2 emission scenarios. Significant losses of salmon habitat are
projected throughout their current range. The number of locations
expected to become unsuitable for both trout and salmon expands
steadily over time, assuming emissions of heat-trapping gases continue
to increase (Exhibit 2).
These results are robust with respect to key model specifications
and assumptions. For a given emissions scenario, the greatest
uncertainty is due to differences among the global climate models, yet
the results provide a valuable indicator of the regions most vulnerable
to loss of cold water fish habitat. Differences among the scenarios for
future emissions of heat-trapping gases also significantly affect the
results, even though none of the scenarios examined assumes that
policies are adopted specifically to address global warming. For all
emissions scenarios our results are likely to understate expected
losses of habitat because of the several dimensions of climate change
and potential effects on habitat that were beyond the scope of the
study. These include potential effects on stream flows, changes to the
temperature of groundwater discharge, changes in ocean conditions, and
other considerations. In addition, these results must be viewed within
the context of other present and future threats to fish habitat, which
are likely to add to the temperature-related losses estimated in the
report.
This analysis demonstrates that it is possible to draw robust
conclusions about the vulnerability of key resources to the effects of
global warming, despite variations in climate model projections. The
results show that future strategies to protect trout and salmon will
need to address the potential effects of global warming.
responding to the threat of global warming
The administration has recognized the threat posed to the United
States by global warming and has reaffirmed the United States'
commitment to the objective of the Framework Convention on Climate
Change, which is to stabilize greenhouse gas concentrations in the
atmosphere at safe levels. Nonetheless, the administration has refused
to consider any mandatory limits on emissions of heat-trapping gases.
This position is both illogical and irresponsible.
The administration has argued, in essence, that mandatory limits on
emissions of CO<INF>2</INF> and other heat-trapping gases would harm
the economy, and that therefore we should rely on voluntary measures
and adapt to changes in climate. The administration has not advanced
any analysis, however, to suggest that voluntary action has any chance
of stabilizing greenhouse gas concentrations in the atmosphere. Indeed,
the United States has now relied on voluntary measures for more than a
decade and emissions have continued to increase.
The administration's claim that setting mandatory limits on
emissions now would harm the economy is equally unsupported by
analysis. While it is possible to construct straw-man proposals that
would be costly, surely there must be some level and timetable for a
CO<INF>2</INF> emission limit that would be affordable. Yet the
administration has rejected any mandatory limit out of hand. In fact,
failure to set limits now will lead to stranded investments in new
highly emitting power plants and other equipment that will become
obsolete when limits are established in the future.
Further delay in establishing mandatory limits on heat-trapping gas
emissions is irresponsible because our window for taking action in time
to stabilize greenhouse gas concentrations at safe levels is rapidly
closing. The IPCC Synthesis Report cited earlier, which was adopted
with the full participation of the administration, makes this quite
clear:
<bullet> ``The severity of the adverse impacts will be larger for
greater cumulative emissions of greenhouse gases and associated
changes in climate.'' (SPM p.9)
<bullet> ``Inertia is a widespread inherent characteristic of the
interacting climate, ecological, and socieconomic systems. Thus
some impacts of anthropogenic climate change may be slow to
become apparent, and some could be irreversible if climate
change is not limited in both rate and magnitude before
associated thresholds, whose positions may be poorly known, are
crossed.'' (SPM p. 16)
<bullet> ``The pervasiveness of inertia and the possibility of
irreversibility in the interacting climate, ecological, and
socio-economic systems are major reasons why anticipatory
adaptation and mitigation actions are beneficial. A number of
opportunities to exercise adaptation and mitigation options may
be lost if action is delayed.'' (SPM p. 18)
Mr. Chairman, global warming poses a clear threat to the United
States. The good news is that this is a threat that we know how to
stop. Now is the time to set mandatory limits on emissions of heat-
trapping gases.
Thank you.
[GRAPHIC] [TIFF OMITTED] 81495.010
Mr. Greenwood. Thank you, Dr. Lashof. The last two times at
my trout fishing in Pennsylvania I caught nothing. Now I know
why.
Dr. O'Brien.
TESTIMONY OF JAMES J. O'BRIEN
Mr. O'Brien. Mr. Chairman, thank you very much for inviting
me today. I have been a physical scientist in oceanography/
meteor- ology for 40 years. I will tell you that in the early
part of my career primarily I was an ocean modeler, and my
students and I are rec- ognized for that internationally. Then
in the Seventies, late Seven- ties and Eighties, we contributed
to understanding of El Nino and how it can be forecast, and
then in the Nineties, while most sci- entists were studying
what was happening in tropical countries, my students and I
concentrated on impacts in the United States, and I have listed
in my paper many of the things we have done.
In 1990 I accepted the pro bono job as the State
Climatologist in Florida. Mr. Deutsch, I am your State
Climatologist. So if you have any constituents who need to know
about climate variability or cli- mate data, please refer them
to my office in Tallahassee.
The reason I took it was very simple. Based on the climate
varia- bility studies, which is part of my theme, the
mitigatable impact in the State of Florida is at least $500
million a year, primarily in forestry and agriculture, tourism
and fisheries. I want to see that we accelerate this
information for the people of Florida.
Recently, we have actually developed--which is now being
used by the wildfire management people in Florida--a way to
predict up to 6 months in advance which county is more
vulnerable for forest fires. You know we have had quite a time
with 3 years of drought in the State of Florida.
So we provide climate advice to the citizens of Florida for
all sec- tors, but particularly agricultural, forestry, tourism
and power gen- eration, and I am funded by NOAA in this area
also to do the re-
search that goes along with providing the information. We work
closely with Tom Karl and he provides us lots of the old data
which is very useful.
Now, turning to the National Regional Assessment of Climate
Change, I was the co-chair for the Southeast Regional
Assessment. Unfortunately, my co-chair, Dr. Ron Ritschard, died
at an early year. We were funded by NASA.
Today I want to focus on the question, and in my scientific
opinion, the Hadley model is a state-of-the-art model, but it
has poor horizontal resolution, inadequate physics,
particularly in the ocean component. And since we deal
primarily with--when we worry about whether it is going to be a
cold winter in Chicago, you know, or too much rain in San
Diego, these are related to what the ocean is doing, the memory
that the ocean has, and it is very important if you are going
to do a 100 year run that you have an adequate ocean model.
A very prominent French physical oceanographer told me
recently--fortunately, he is quite young--that he hopes that
before he dies, the ocean models used by these global climate
models represents something that he knows that's in the real
ocean.
Anyway, my opinion is that to Canadian model is very flawed
and should never have been used. Even when it was first
distributed to the team across the United States, the data was
represented incorrectly geographically, and the attitude was,
well, maybe that is not real important. I have no knowledge
whether they actually ever fixed it up.
You know, I enjoy learning about climate variability over
the United States, such as floods, droughts, freezes, and
hurricanes. I don't have time to go into what our studies have
shown us, but for the average citizen, you know, they are
wondering about the variability in climate. Okay? Is it
different than, you know, my grandfather told me about? Is my
experience different?
They are not really interested in whether the average
temperature is going to rise 3 to 5 degrees Fahrenheit in 100
years. They are interested in is winter going to be colder than
normal and many other things.
For example, one of the things I discovered early on the
Canadian model is they didn't have El Ninos in it. Now I was
told it is in there, but I have looked at the data. I am an
expert in that, and I couldn't find any sign of it, and I
cannot imagine any climate model that we are going to run for
100 years that doesn't have some robust signal of the way that
our climate variability is changing on year to year and
decadals.
In the Hadley model, you see that, but you don't see that
in the Canadian model. We are three State climatologists here
today, and another one from the State of Alabama, Dr. John
Christie, says that he believes that the Canadian model was
modeling another planet than this one.
Okay. Can we do better? I think we can really do better,
and I actually have some very good news. Yesterday when I came,
someone delivered to me a testimony of James Mahoney, who is
now the Assistant Secretary of Commerce for Ocean Atmospheres,
and he on July 11 this year before the Committee on Commerce,
Science and Transportation of the U.S. Senate had delivered
this paper which I can add into the record.
In just part of it he says that uncertainties in climate
models address exactly what we are talking about. It says the
poor regional performance of current general circular models
severely restricts the examination of potential global climate
influence on key regional systems. I am so delighted that at
very high level in government that that is now understood.
I am going to conclude now and just say that I believe
global climate change would occur. I am not convinced that we
are going to see it in terms of surface temperature increase or
sea level increase. It will change. We need to address what to
do.
In my outline I have indicated that we need a new Manhattan
type project. We need an institute outside the government, labs
in the government, where we hire the best managers,the best
scientists, and give them finally decent computers so they can
do the job correctly and make adequate American models.
There is a model like this, sir. The model is the European
Centre model for medium range weather prediction where the
European nations got together and formed a center which is
physically in Britain but has members all over. I think nobody
will disagree in this room that they give the best week-long
weather forecasts of anyplace. The reason they do is because of
a unique way it is managed--good managers that don't stay there
for lifetimes, good scientists that stay 5 to 10 years and then
go to their home countries, and the best computers in the world
for doing the problem right.
The technical director of the Center for European Centre
for Medium Weather Prediction, a good Irishman like me,
recently said to General Kelly, the head of the Weather
Service--He says, General Kelly, we are two decades ahead of
you now; why don't you just buy our results and shut down the
operation.
Thank you very much.
[The prepared statement of James J. O'Brien follows:]
Prepared Statement of James J. O'Brien, Robert O. Lawton Distinguished
Professor, Meteorology and Oceanography, The Florida State University
introduction
I have been a physical scientist in oceanography and meteorology
for 40 years. In my early years, my graduate students and postdocs
concentrated primarily on modeling time dependent ocean motions. In the
late 1970's and 1980's, we contributed to the physical understanding of
El Nino. Namely, how it works and how it can be forecast.
In the 1990's, while most other scientists were applying ENSO
forecasts to tropical countries, my students and I have concentrated on
impacts in the United States. We have written papers on: ENSO and
Atlantic Hurricanes; ENSO and Tornadoes; ENSO and Precipitation; ENSO
and Temperature; ENSO and Wild Fires (In Florida); ENSO and Snowfall;
ENSO and Excessive Wind Events; ENSO and Great Lakes Snow Events; and
ENSO and Freezes in Central Florida.
In 1999, I accepted the pro bono job as official State of Florida
Climatologist. We have been advising the Florida Commissioner of
Agriculture on wild fire forecasts, droughts, hurricanes, etc. We
provide climate advice to the citizens of Florida for all sectors, but,
particularly agriculture, forestry, fisheries, tourism and power
generation.
In some local circles, I am labeled, Dr. El Nino for my research.
Turning now to the National Regional Assessment of Climate Change,
I was the Co-Chair for the Southeast Regional Assessment. (My Co-Chair,
Dr. Ron Ritschard, recently died at a young age). Our work was funded
by NASA, Huntsville, Alabama.
In the early beginnings of the National Regional Assessment, the
entire U.S. team met and we agreed there would be ``ONE'' Global
CO<INF>2</INF> doubling model so everyone referring to future
projections would be on the same page. There were two choices: (1) The
Hadley, (British model), or (2) The Max Planck (German model). The
Hadley model was selected. Subsequently, I attended a meeting of the
U.S. National Resource Board Committee on Climate. Many senior
scientists were shocked that there was no American models. In due time,
a very new recent model, the Canadian Model was added for our use. It
was recently computed so no documentation or response of this model was
available to the assessment teams.
In my opinion, the Hadley model is a state-of-the-art model with
poor resolution, inadequate physics--particularly, the ocean component.
The Hadley Model gives reasonable projections, but it is still flawed
and I am sure that, in due time, will be improved. As better ocean
models are improved in climate models, the future changes are greatly
reduced.
The Canadian's model is flawed, and, in my opinion, should never
have been used. My effort to capture the attention of the leaders to
recognize this were rejected outright. My team discovered that,
initially, the data provided to the team had been incorrectly
registered with respect to the geography of the U.S. Since the model
has horizontal grid boxes around 500 km on a side, being set off by one
grid, really confuses geographic identification. (As an aside, I do not
know if this was fixed, but I was told it can't make any difference).
I really enjoy learning about climate variability over the United
States, such as droughts, floods, freezes, hurricanes, etc. For the
citizen for whom climate is important, it is the variability which
matters! It is not whether the average temperature will rise 3-5 deg.F
in 100 years. The citizen wants to know ``Is this winter going to be
colder than normal?'' and other simple questions. I discovered that we
could not find ENSO variability in the ocean model of the Canadian
model. I was told it was there, but it makes no difference if it is too
small.
Mr. Chairman, the variability of climate over most of the United
States is primarily controlled by ENSO and other ocean-related
phenomena (North Atlantic Oscillation, and the Pacific Decadal
Oscillation) and land use changes. I cannot accept a 100 year climate
run as useful if it doesn't also include the observed variability in
the climate system.
What is the climate system? It is the entire atmosphere, ocean,
land, ice systems which are heated by the sun. The chemistry of global
climate change is completely correct. We have an excellent scientific
understanding of how radiatively-active gases such as carbon dioxide,
methane and water vapor can delay heat in the climate system. There is
an assumption that this extra heat will manifest itself in raising the
temperature of the biosphere--that portion of the climate system in
which we humans live. The data measured from the actual climate system
seems to indicate other processes are dominate, such as stronger mid-
latitude storms which are important for distributing the extra heat. In
my opinion, even the current models are not capable in calculating the
climate system well enough for policymakers to believe in any
projection.
Can we do it better? I believe we can, but it will take a new
effort and considerable investment. We know most of the physics of the
climate system. In order to calculate the variability of the system, we
need adequate computers. We need the kind of investment in computers
that the Congress funds to DOD, NSF, NSA, etc.
I propose a ``Manhattan Type Project'' to estimate future climate
variability for our National Security. Any future climate change will
probably require trillions of dollars to adjust our culture or mitigate
the consequences. My vision is a NEW Institute, outside the government
with top management, the best scientists and adequate resources. My
estimate is $50M/year for at least 10 years.
When I suggest this, OMB folks usually ask me, ``Dr. O'Brien, where
are we going to find that money?'' My answer is, ``Give us 2 attack
helicopters'' monies, and we will be happy for a few years. Give us a
fighter jet monies, we will be very happy for a few years. Give us an
aircraft carrier monies, and we will never ask for any more
resources''. The Congress has to decide on the priorities. Do we want
to understand the future climate or not?
Returning to my belief, that we can do better in modeling climate,
I am encouraged that each generation of climate change modeling gets
better. The original CO<INF>2</INF>-doubling model by NASS,GISS under
the leadership of Dr. Jim Hansen, estimated around 10 deg.F surface
temperature change by 2050. This was so dramatic because no ocean was
included. I remember reading in the Tallahassee Democrat, a story that
said, as a result of the GISS model, that sea-level would rise 3 meters
or 7-10 feet by 2050. The current IPCC estimates a few degrees
temperature rise by 2100 and a doubling of the current sea-level rise
of around 8-10 inches to 20 inches as the worst case by 2100.
Certainly, policymakers will react differently to plan for a two feet
rise in 100 years vs. 10 feet rise in a generation.
Let me provide one more remark on sealevel rise. In order to double
sealevel, one would expect to observe an increased rate of rise by
2002. Everyone agrees that the current average rise is about 7-10
inches a century, averaged over the globe. However, the experts who
have tried to find any acceleration find none.
How about global warming in the United States? I will leave this
subject to my fellow climatologist, Dr. Tom Karl. I am, however, the
State Climatologist of Florida. In Florida, the cities are warming at
the rate of about one degree in the entire 20th century. But the rural
places are cooling at the rate of more than one degree per century. I
have included some graphics in my presentation documenting this for
minimum temperature over the entire 20th Century. What is happening? My
fellow, State Climatologist, from Colorado, Dr. Roger Pielke, Sr.,
explains this by land use changes. Dr. Karl has published work showing
the cooling in the Southeast United States, but unfortunately, the
summary of average temperature in Florida in the last century, in the
S.E. Assessment summary, shows Florida warmer than the rural data would
dictate.
Finally, the ocean part of the global climate system models are
very inadequate. The research community is aware that warm and cold
ocean currents are very important in predicting the weather even for 10
days. It is critical to model the oceans correctly if a global climate
model is expected to work at all. A young French ocean modeler said to
me recently, ``I hope that the ocean models used by global climate
models look like the real ocean before I die!''
There are hundreds of scientists other than climate modelers that
have been told the Hadley and Canadian models are good projections of
the future. This is a shame. When I joined the U.S. National Assessment
Team as Co-Chair of the Southeast Regional Assessment, a bright young
EPA ecologist from Louisiana reported to me that the number of
hurricanes in the Gulf of Mexico were increasing due to global warming.
I was unaware of this. Consequently, my students and I did a study. We
found, that, in fact, the number of hurricanes have decreased
significantly in the Gulf of Mexico. This is a published paper. 1998:
Are Gulf Hurricanes Getting Stronger? Bull. Amer. Meteorol. Soc.,
79(7), pp. 1327-1328 (with Bove, M.C., and D. F. Zierden).
conclusion
Global climate changes will occur. Whether surface temperatures
will increase due to radiatively-active emissions is not clear. The
Global Climate System must change. In order to address what the nation
needs to do, I recommend a large investment in improving the basic
understanding by investing in very good global climate system
calculations.
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Mr. Greenwood. Thank you. My staff said it sounds like a
field hearing. We will have to go over to Europe and take a
look at that.
Dr. Pielke.
TESTIMONY OF ROGER A. PIELKE, SR.
Mr. Pielke. Yes, Mr. Chairman, members of the committee,
thank you for the opportunity to present testimony. I received
my PhD and Master's degree from Penn State in the Department of
Meteorology, and since the 1960's my research has focused on
weather and climate studies using both models and observations.
In my testimony I would like to convey two main points:
First, that the perspective I am presenting today does not
easily fit into the conventional two-sided debate over climate
change. This third perspective, as I have written elsewhere,
suggests that humans have an even greater impact on climate
than is suggested by the international and national
assessments.
The human influence on climate is significant and multi-
faceted. However, any attempt to accurately predict future
climate is fundamentally constrained by the significant and
multi-faceted characteristics of the human influence on
climate. By focusing on vulnerabilities rather than prediction
as a focus of research, I believe that the scientific community
can provide more comprehensive and likely more useful
information to decisionmakers.
These points are consistent with the American Association
of State Climatologists Policy Statement on Climate Variability
and Change which was approved on October 25, 2001, and I will
read part of that statement:
``Our statement provides the perspective of our Society on
issues of climate variability and change. Since the Society
members work directly with users of climate information at the
local, State and regional levels, it is uniquely able to put
global climate issues into the local perspective which are
needed by users of climate information. Our main conclusions
are as follows:
``First, past climate is a useful guide to the future.
Assessing past climate conditions provides a very effective
analysis tool to assess societal and environmental
vulnerability to future climate, regardless of the extent the
future climate is altered by human activity. Our current and
future vulnerability, however, will be different than in the
past, even if the climate were not to change, because society
and the environment change as well. Decision makers need
assessments of how climate vulnerability has changed.
``Two, climate prediction is complex with many
uncertainties. The AASC recognizes climate prediction is an
extremely difficult undertaking. For time scales of a decade or
more, understanding the empirical accuracy of such predictions,
called verification, is simply impossible, since we have to
wait a decade or longer to assess the accuracy of the
forecasts.''
In the remainder of my 5 minutes I will discuss one example
of the scientific basis that underlie the statement. Greater
detail is available in the peer reviewed scientific
publications that are listed at the end of my written
testimony.
A fundamental basis of the U.S. National Assessment is the
use of the Canadian and Hadley Centre General Circulation
Models to project the future state of the climate as the basis
for discussion of climate impacts and ultimately alternative
courses of action by decisionmakers. The perspective I offer
here suggests that in relying on GCMs to, in effect, bound the
future state of the climate, the U.S. National Assessment may
have had the effect of underestimating the potential for change
and overestimating our ability to accurately characterize such
changes with computer models.
The hypothesis for using these models is that including
human caused increases of carbon dioxide and other greenhouse
gases and aerosols in the models are sufficient to predict long
term effects on the climate of the United States. The position
presented here is that such forcings are important, but a
subset of those needed to develop plausible projections, and
even if all the forcings were included, accurate long term
prediction would remain challenging, if not impossible.
To test the hypothesis that GCMs can accurately project
climate, it is possible to compare model performances with
observed data for the period 1979-2000. One test is the ability
of the model to predict the averaged temperatures of the
earth's atmosphere over this 20-year period. Such a test is a
necessary condition for regional projection skill, since if
globally averaged long term changes cannot be skillfully
projected, there will necessarily be no regional skill.
During this period, for example, at around 18,000 feet
above sea level, the Canadian GCM projects a 0.7 degree C
warming of the global averaged temperature. The Hadley Centre
model also has atmosphere warming for this time period. The
observations, in contrast, have no statistically significant
change in these averaged atmospheric temperatures.
Thus, either the models or the observations must be
incorrect. Both cannot be correct. Since, for the 1979-2000
time period, satellite, radiosonde and National Center for
Environmental Prediction model reanalyses each agree closely
with respect to global averages, the observations should be
interpreted as our best estimate of reality.
The scientific evidence, therefore, is that the models have
failed to replicate the actual evolution of atmospheric
temperatures over the time period 1979-2000. Thus using the
results of these models as the basis for assessments, much less
for particular decisions, for the next several decades is not
justified. Such models clearly have usefulness as scientific
tools with which to conduct sensitivity experiments, but it is
important to not overstate their capabilities as predictive
tools.
One major reason for this difficulty is the absence and/or
inadequate representation of significant human caused forcing
of the climate. These include land use changes over time, the
effect of aerosols on clouds and precipitation, and the
biogeochemical effect of carbon dioxide. The Intergovernmental
Panel on Climate itself concludes that there is a very low
level of scientific understanding of these forcings.
The importance of one of these effects can be illustrated
by a just published paper of the influence of human caused land
use change on the global climate. Even with a conservative
estimate of land use change, the global redistribution of heat
and the effects on regional climate is at least as large as
simulated by the existing GCM simulations. However, even when
these forcings are included, the complex interactions among the
components of the climate system will likely limit our ability
to skillfully predict the future. Indeed, we cannot even
predict with any skill beyond a season in advance, and then
only under special situations such as an evolving El Nino.
As a result, we have--There is a new book that is coming
out by the International Geosphere-Biosphere Programme titled
``Vegetation, Water, Humans and the Climate,'' and there is a
chapter in there which talks about how to evaluate the
vulnerability in changing environmental conditions.
This chapter basically proposes that we start first from an
assessment of vulnerability. Only at that point do we bring in
these other tools, such as GCM models, historical record, and
so forth.
Even the IPCC, I am told by some colleagues, is starting to
embrace a greater focus on vulnerability, and several U.S.
programs, most notably the Regional Integrated Science and
Assessments program of NOAA, have also acknowledge the
importance of vulnerability as a scientific organizing theme.
Let me conclude by saying I wish to underscore that the
inability of the U.S. National Assessment models to skillfully
predict climate change does not mean that the radiative effect
of anthropogenic greenhouse gases on climate is not important,
nor does it suggest which policy responses to the issues of
climate change make the most sense.
Such matters of policy go well beyond any discussion of the
issues of science and well beyond the information presented in
my testimony today.
Effective mitigation and adaptation policies in the context
of climate variability and change do not depend on accurate
prediction of the future and, consequently, a lack of ability
to generate accurate predictions should not be used as a
justification to ignore the policy challenges presented by
climate. Too often, debate over climate substitutes for debate
over policy.
Thank you.
[The prepared statement of Roger A. Pielke, Sr. follows:]
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Mr. Greenwood. Thank you, Dr. Pielke.
Dr. Michaels.
TESTIMONY OF PATRICK J. MICHAELS
Mr. Michaels. Mr. Chairman, I am sitting over here. Dr.
O'Brien is much more handsome.
I am a Professor of Environmental Sciences at the
University of Virginia and past President of the American
Association of State Climatologists, and I should say my
colleague, Roger, is the future President.
I offer you a word of caution on the science about which we
base our Nation's policy on global warming. Mr. Chairman, would
you tell people what was going to happen to the United States
tempera- ture based upon a table of random numbers? I don't
think so. But that is what happened in the assessment on
climate change.
Effects have causes. Our society is currently confronting a
poten- tially serious effect, the specter of climate change
caused by human alteration of the atmosphere. We ask scientists
to quantify these causes and effects. They pursue truth by
making hypotheses and testing them against reality. In climate
science, these hypotheses
are computer models. If they are at odds with reality, they
only inform bad policy.
It is absolutely logical to want a scientific assessment of
the effect of human induced climate variability on the U.S.
Coming from the University of Virginia, I am commanded, as you
know, to refer to its founder, Thomas Jefferson. Had he been
alive and seen changes in the greenhouse effect that we have
observed today, he would ask scientists what will happen to
America's climate?
So let's transport Mr. Jefferson's scientists in the 19th
Century, newly minted in the environment, naive, not involved
in the political process. What would they do? Well, they would
probably learn about computer models such as we have today, and
then they would use those computer models to drive impact of
climate change on other aspects of our society, our farms, our
forests, our water supply.
That is, in a sense, what was used for the methodology for
the U.S. National Assessment on Climate Change. Now what models
would they choose? I argue they would find a climate model that
predicted large changes, one that predicted medium changes, and
probably a third that predicted small changes.
In the very real case of the 20th Century National
Assessment on Climate Change, two models were chosen. The first
from the Canadian Climate Center, shown here in this Vu-Graph,
predicts the largest changes of temperature of any of the
models considered here in the report.
It is also different than the dozens of other climate
models. It is against the consensus of climate models, as
described by the United Nations, because it has an exponential
increase in temperature, meaning an increase which gets larger
and larger in terms of rate, as opposed to the average of
models. This is from the United Nations' new summary on climate
change, which you can see clearly is a straight line.
So not only have we chosen the most extreme temperature
prediction, we have chosen one whose mathematical and
functional form is at variance to the consensus of models.
The second model used in the Assessment, from Britain's
Hadley Center, predicts the largest changes in rainfall. These
are the precipitation forecasts from the models considered. You
can see this is at major variance to any of the other consensus
models that we have.
Consequently, the very real 20th Century scientists, as
opposed to our 19th Century hypothetical scientists, chose the
most extreme forecasts to guide our national assessment. I
would bet our 19th Century scientists would ask another
question: Do these models work? And they would test them, and
they would discover that both the Hadley and the Canadian
models chosen by the 20th Century counterparts were worse than
a table of random numbers when applied to United States
temperatures.
At this point, I believe the 19th Century scientists would
have stopped and said we do not have the tools to forward
project climate. They might have said, perhaps we should take a
look at how U.S. climate has changed as the greenhouse effect
has changed and as global temperatures have changed.
The very real 20th Century assessment teams was informed in
the review process about this problem with the models. IN
public comments, it was swept aside with a statement that
United States temperatures are warming, model temperatures are
warming and, therefore, everything is fine.
In fact, the Canadian model predicts recent years to be 2.7
degrees warmer than the years in which the Canadian model
starts. The observed change in U.S. temperature is .9 degrees,
a 300 percent error.
Random numbers are not plausible scenarios. It is no longer
science when our results are worse than random numbers. It is
mathematical philosophy. It is scenario building, but it is not
science. Mr. Chairman, whatever is based upon models that do
not better than random numbers is science fiction, glossy,
colorful, meticulous, but fiction.
Unfortunately, the assessment serves as the basis for
sweeping legislation on global warming at both the Federal and
the State levels. Using computer models that demonstrably do
not work can only inform bad policy.
The first time I testified on the subject of global warming
was in February 1889--yes, it seems like 1889--1989 before this
very Energy and Commerce committee. I stated then that warming
was likely to be at the lowest end of projected ranges based on
a comparison of then existing models and observed temperatures.
I stated that ``our policy should be commensurate with our
science.''
Thirteen years later I am compelled to tell you exactly the
same. Thank you.
[The prepared statement of Patrick J. Michaels follows:]
Prepared Statement of Patrick J. Michaels, Department of Environmental
Sciences, University of Virginia
This testimony makes no official representation for the University
of Virginia or the Commonwealth of Virginia, and is tendered under the
traditional protections of academic freedom.
Effects have causes. Confronting our society today is a potentially
serious effect, climate change, caused by human influence on our global
atmosphere.
The quantitative tools of mathematics and science are what we use
to inform rational analysis of cause and effect. Science, in
particular, obeys a rigid standard: that the tools we use must be
realistic and must conform to observed reality. If they do not, we
modify or abandon them in search of other analytical methods. Whenever
the federal government releases a comprehensive science report, the
public naturally assumes that it has passed these tests. The documents
we will discuss today failed those tests. This failure was ignored in
the public review process.
There is no doubt that the issue of climate change rightly provokes
private citizens and our government to ask what its potential effects
might be on the United States. That was the purpose of the recent
report Climate Change Impacts on the United States: The Potential
Consequences of Climate Variability and Change. This document is often
called the ``U.S. National Assessment'' (USNA) of climate change. This
report forms much of the basis for Chapter 6 of the U.S. Climate Action
Report--2002, a chapter on ``Impacts and Adaptation'' to climate
change.
The USNA began with a communication from President Clinton's
National Science and Technology Council (NSTC), which was established
in 1993. According to the USNA, ``This cabinet-level council is the
principal means for the President to coordinate science, space and
technology policies across the Federal Government.'' ``Membership
consists of the Vice President [Al Gore], the Assistant to the
President for Science and Technology, Cabinet Secretaries and Agency
heads . . .'' The Council is clearly a political body (``coordinating .
. . policies'') rather than a scientific one.
This NSTC was, in turn, composed of several committees, including
the Committee on Environment and Natural Resources, chaired in 1998 by
two political appointees, D. James Baker and Rosina Bierbaum. Baker
developed a further subcommittee of his committee, the Subcommittee on
Global Change Research, to ``pro- vide for the development . . . of a
comprehensive and integrated . . . program which will assist the Nation
and the world to understand, assess, predict [emphasis added], and
respond to human-induced and natural processes of global change.'' Ul-
timately, this resulted in the selection of the National Assessment
Synthesis Team (NAST).
NAST was confronted with a daunting task, detailed in the schematic
below. The chain of cause and effect begins with industrial activity
and the combustion of com- pounds that alter the atmosphere's radiative
balance. These are then distributed through the atmosphere. These
affect the climate of the United States. Then, those changes in climate
are input to a subsidiary series of computer models for forest growth,
agriculture, etc.
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An understanding of the effects of climate change on the United
States requires that there be no substantially weak links in this
catena. As an example of a rel- atively strong link, I would estimate
that we understand about 70 percent of the changes in atmospheric
carbon dioxide that result from human activity. The reason this number
is not 100 percent largely stems from the fact that the current con-
centration of carbon dioxide seems low, given the amount emitted and
assumptions about how it distributes through the atmosphere and the
biosphere, and how it eventually returns to the soil and the ocean
bottom.
There are two main ways to assess the most important of these
linkages, which is between ``Atmospheric Changes'' and ``Climate
Changes in the United States.'' One involves the use of computer
simulations, known as General Circulation Models (GCMs) to estimate how
climate changes as a result of atmospheric alterations. An alternative
method for assessment is described on page 10 of this Testimony.
There are literally dozens of GCMs currently available, and the
USNA considered a subgroup of these models. Eventually, they selected
two, the Canadian Climate Centre model, acronymed CGCM1, and another
from the United Kingdom Meteoro- logical Office, known as HadCM2
<SUP>1</SUP>. The prime outputs of these models that are im- portant
for the assessment of climate change are temperature and precipitation.
---------------------------------------------------------------------------
\1\ In 1998, the National Research Council report Capacity of U.S.
Climate Modeling to Support Climate Change Assessment Activities
strongly remonstrated against the use of foreign models to assess U.S.
climate. According to the NRC, ``. . . it is inappropriate for the
United States to rely heavily upon foreign centers to provide high-end
modeling capabilities. There are a number of reasons for this including
. . . [the fact that] decisions that might substantially affect the
U.S. economy might be based upon considerations of simulations . . .
produced by countries with different priorities than those of the
United States.''
---------------------------------------------------------------------------
In using GCMs to project future climate at regional scales, the
USNA clearly placed itself squarely against the consensus of world
climate science. In 2001, the United Nations' Intergovernmental Panel
on Climate Change (IPCC) compendium on climate change, the Third
Assessment Report, states:
``Despite recent improvements and developments . . . a coherent
picture of regional climate change . . . cannot yet be drawn.
More co-ordinated efforts are
thus necessary to improve the integrated hierarchy of models .
. . and apply these methods to climate change research in a
comprehensive strategy.''
In other words, even three years after the Assessment team began
its report rely- ing on GCMs, the consensus of world climate science
was that they were inappro- priate for regional estimates, such as
those required for the United States.
choice of extreme models
As shown in the IPCC's Third Assessment Report of climate change,
the average behavior of GCMs is to produce a linear (constant) rate of
warming over the project- able future. In other words, once warming
begins from human influence, it takes place at a constant, rather than
an exponentially increasing rate.
However, the CGCM1 is an outlier among the consensus of models,
producing a warming that increases as a substantial exponent. This
behavior can be seen in Fig- ure 1a, taken directly from the USNA, in
which the CGCM1 clearly projects more warming than the others
illustrated in the USNA.
The USNA also illustrates a similarly disturbing behavior for
precipitation. Figure 1b, again taken directly from the USNA, shows
that the other model employed, HadCM2, predicts larger precipitation
changes than the others that are illustrated in the USNA.
A close inspection of Figure 1a reveals that CGCM1 predicts that
the tempera- tures in the United States at the end of the 20th century
should be about 2.7 deg.F warmer than they were at the beginning, but
the observed warming during this time, according to the most recent
analysis from the National Climatic Data Center, is 0.9 deg.F. CGCM1
is making a 300 percent error in its estimation of U.S. tempera- ture
changes in the last 100 years.
My colleague Thomas Karl, Director of the National Climatic Data
Center and co- chair of the USNA synthesis, explained that the reason
CGCM1 was chosen was be- cause it was one of only two models (the other
was HadCM2) that produced daily temperature output, and that this was
required to drive some of the subsidiary mod- els, such as those for
forest impacts.
Michael MacCracken, Executive Director of the National Assessment
Coordination Office, told me otherwise. He said that the two models
were selected because they gave extreme results, and that this was a
useful exercise. How the explanations of the co-chair and the Executive
Director could be so different is still troubling to me.
the failure of the models
GCMs are nothing more than hypotheses about the behavior of the
atmosphere. The basic rule of science is that hypotheses do not
graduate into facts unless they can be tested and validated against
real data.
As part of my review of the USNA in August 2000, I performed such a
test. The results were very disappointing. Both CGCM1 and HadCM2 were
incapable of simu- lating the evolution of ten-year averaged
temperature changes (1991-2000, 1990- 1999, 1989-1998, etc. . . . back
to 1900-1909) over the United States better than a table of random
numbers. In fact, the spurious 300 percent warming error in CGCM1
actually made it worse than random numbers, a dubious scientific
achieve- ment, to say the least.
I wrote in my review:
``The essential problem with the USNA is that it is based
largely on two climate models, neither one of which, when
compared to the 10-year smoothed behavior of the lower 48
states reduces the residual variance below the raw variance of
the data [this means that they did not perform any better than
a model that simply assumed a constant temperature]. The one
that generates the most lurid warming scenarios--the . . .
CGCM1 Model--also has a clear warm bias . . . All implied
effects, including the large temperature rise, are therefore
based upon a multiple scientific failure [of both models]. The
USNA's continued use of those models and that approach is a
willful choice to disregard the most fundamental of scientific
rules . . . For that reason alone, the USNA should be withdrawn
from the public sphere until it becomes scientifically based.''
The Synthesis Team was required to respond to such criticism.
Publicly, they de- flected this comment by stating that both U.S.
temperatures and model tempera- tures rose in the 20th century, so use
of the models was appropriate!
This was a wildly unscientific response in the face of a clear,
quantitative anal- ysis. The real reason for the models' failure can be
found in the USNA itself (Figure 11 in Chapter 1 of the USNA Foundation
document). It is reproduced here as our Figure 2. The discrepancies
occur because:
1. U.S. temperatures rose rapidly, approximately 1.2 deg.F, from about
1910 to 1930. The GCMs, which base their predictions largely on
changes in atmospheric car-
bon dioxide, miss this warming, as by far the largest amounts of
emissions were after 1930.
2. U.S. temperatures fell, about 1.0 deg.F, from 1930 to 1975. This is
the period in which the GCMs begin to ramp up their U.S.
warming, and
3. U.S. temperatures rose again about 1.0 deg.F from 1975 to 2000,
recovering their decline between 1930 and 1975.
It is eminently clear that much of the warming in the U.S. record
took place before most of the greenhouse gas changes, and that nearly
one-half of the ``greenhouse era,'' the 20th century, was accompanied
by falling temperatures over the U.S. These models were simply too
immature to reproduce this behavior because of their crude inputs.
Despite their remarkably unprofessional public dismissal of a
rigorous test of the USNA's core models, the Synthesis Team indeed was
gravely concerned about the criticism. So much so, in fact, that they
replicated my test, not just at 10 year-intervals, but at scales
ranging from 1 to 25 years.
At the larger time scales, they found the models applicable to
global temperatures. But over the U.S., not surprisingly, they found
exactly what I had. The models were worse than random numbers.
It is difficult for me to invoke any explanation other than
political pressure that would be so compelling as to allow the USNA to
continue largely unaltered in this environment. And so the USNA was
rushed to publication, ten days before Election Day, 2000.
Given the failure of the models when directly applied to U.S.
temperatures, there were other methods available to the USNA team. One
would involve scaling various global GCMs to observed temperature
changes, and then scaling the prospective global warming to U.S.
temperatures. The first part of this exercise has been performed
independently by many scientists in recent years, and published in many
books and scientific journals. It yields a global warming in the next
100 years of around 2.9 deg.F, which is at the lowest limit of the
range projected by the IPCC in its Third Assessment Report.
If applied to the United States this would similarly project a much
more modest warming than appears in the USNA. Perhaps that is the
reason such an obviously logical methodology was not employed after the
failure of the models was discovered by a reviewer and then
independently replicated by the USNA itself.
effect of the usna
This discussion would be largely academic if the USNA were an
inconsequential document. But, as noted above, it served largely as the
basis for Chapter 6 of the U.S. Climate Action Report--2002. Further,
it served as the basis for legislative findings for S. 556, a
comprehensive proposal with extensive global warming related
provisions, and it was clearly part of the findings for legislation
restricting carbon dioxide emissions recently passed by the California
Legislature. Hardly a week goes by without some press reference to
regional alterations cited by the USNA. Would the USNA have such
credibility if it were generally known that the driver models had
failed?
solving the structural problems with the usna
The USNA synthesis team contains only two individuals who can
logically claim, in my opinion, to be climatologists. Of the entire 14-
member panel, there is not one person who has expressed considerable
public skepticism about processes that were creating increasingly lurid
scenarios for climate change with little basis in fact. As noted above,
the administrative structure that selected the synthesis team was
clearly directed by political appointees, which no doubt contributed to
this imbalance.
In my August 2000 review, I wrote:
``Finally, we come to the subject of bias in selection of USNA
participants. There are plenty of knowledgeable climatologists,
including or excluding this reviewer, who have scientific
records that equal or exceed those of many of USNA's
participants and managers. They would have picked up the model
problem [that extreme versions were selected, and that they
could not simulate U.S. temperatures] at an early point and
would not have tried to sweep it under the rug. Where is Bob
Balling? Where is Dick Lindzen? Where are [Roger] Pielke Sr.,
[a participant in this hearing], [Gerd] Weber or [Roy]
Spencer?''
My review was tendered shortly after attending the annual meeting
of the American Association of State Climatologists (AASC) in Logan,
Utah, in August 2000. The AASC is the only professional organization in
the U.S. devoted exclusively to climatology. Membership consists
largely of senior scientists who are tasked by their states, usually
through the state's major universities, to bring climate information
and services to the public. Until 1972, the State Climatologists were
employees of the U.S. Department of Commerce.
In my review of the USNA I further noted that:
``Yesterday . . . I returned from the annual meeting of the
American Association of State Climatologists (I am a past
president of AASC). There were roughly 100 scientists present.
I can honestly state that not one positive comment was tendered
to me about the USNA, out of literally dozens made. If the
report is published in anything like its current form, I
predict it will provoke a public examination of how and why the
federal science establishment [could have produced such a
document].''
That prediction has come true. It is why we are here today.
Besides being research scientists, the State Climatologists are
interpretive professionals who deal with the climate-related problems
of their states on a day-to-day basis. It's hard to imagine a better-
suited team of professionals to provide a significant leadership role
in any new Assessment.
recommendations
1. The current USNA should be redacted from the public record. 2.
Another Assessment should be undertaken, this time with a much more
diverse synthesis team selected by a more diverse political process. 3.
Professional interpreters of climate information, who will be called
upon to explain or defend any future Assessment, such as the State
Climatologists, should provide strong input to any new report. 4. Any
new Assessment must be based only upon hypotheses that can be verified
by observed data.
conclusion
The 2000 document, Climate Change Impacts on the United States: The
Potential Consequences of Climate Variability and Change, which served
as the basis for an important chapter in the new Climate Action
Report--2002, was based on two computer models which were extreme
versions of the suite of available models. The two selected models
themselves performed no better than a table of random numbers when
applied to U.S. temperatures during the time when humans began to
subtly change the composition of the earth's atmosphere. As a result,
both reports are grounded in extremism and scientific failure. They
must be removed from the public record.
This scientific debacle resulted largely from a blatant intrusion
of a multifaceted political process into the selection process for
those involved in producing the U.S. National Assessment. The clear
lesson is that increased professional diversity, especially
intermingling state-based scientists with the federal climatologists,
would have likely prevented this tragedy from ever occurring.
References
IPCC (2001). Climate Change 2001: The Scientific Basis.
Contribution of Working Group I to the Third Assessment Report of the
Intergovernmental Panel on Climate Change. Houghton JT, Ding Y, Griggs
DJ, Moguer M, van der Linden PJ, Dai X, Maskell K, Johnson CA, (eds).
Cambridge University Press, Cambridge, UK, 881pp.
National Assessment Synthesis Team (2001). Climate Change Impacts
on the United States: The Potential Consequences of Climate Variability
and Change. Report for the U.S. Global Change Research Program,
Cambridge University Press, Cambridge, UK, 620pp.
U.S. Department of State. U.S. Climate Action Report--2002.
Washington, D.C., May 2002.
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Mr. Greenwood. Thank you.
The Chair recognizes himself for 10 minutes for inquiry.
Dr. Karl, I want to start with you. In your written
testimony, you note several factors that cause climate change
and variability that were not included in assessment models.
This is on page 2 and more extensively on page 10. You also
note that foreign models were problematic for use in the United
States, and cite a National Research Council report which you
chaired--this is from page 4 of your testimony--that
underscored these important limitations.
Can you explain why, given your own knowledge about the
models' limitations, you went ahead with these models? Weren't
they too limited for the public uses that would result from
this report?
Mr. Karl. Sure. I would be happy to, Mr. Chairman.
The two models that were selected, by no means, were
perfect models, and no model is perfect. I don't think anyone
would argue that. I think the question that we all asked
ourselves is whether they would be useful tools.
As I tried to indicate in my testimony, we believe they
were quite effective as useful tools, along with the
observational data and ``what if'' scenarios. Maybe I can give
you a little bit of an analogy.
In daily weather forecasting today, operational weather
models cannot predict tornados or hailstones, but yet our
weather forecasts do give an idea of when we would expect
tornados and hailstorms and are largely based on those
operational weather models, despite the fact that the
operational weather models do not have the high resolution
details to be able to predict those phenomena.
So in that sense, these models, we felt, were effective
tools and, as I tried to indicate in my testimony, there was a
number of issues that were neglected, those being changes in
land use, as Dr. Pielke had described, changes in black soot
and other aerosol, changes in stratospheric ozone depletion.
Those simulations weren't available at that time, but the
intent of the assessment was to look into the 21st Century, and
if you look at the IPCC results, those forcings, although are
important and it is important to try and understand the
regional details, the two most important factors, that being
aerosols and increases in greenhouse gases, were included in
the models.
So for that reason, we thought that it was a valuable tool
to go ahead and use and, in fact, if we had not used them, I
think we would have been negligent.
Mr. Greenwood. How do you respond to Dr. Michaels'
suggestion that these models haven't produced more--anything
different than a random set of numbers?
Mr. Karl. Random numbers? Yes, and I am glad you asked that
question, because we have conducted those tests on those models
similar to what Dr. Michaels has suggested. First, let me
qualify. There's many tests you can do on models, and no one
test should be used to say whether or not a model is effective.
There's been many types of tests applied to these models
and other models, but I can say the same kind of tests that Dr.
Michaels suggests was applied to precipitation data over the
U.S., and the model showed significant skill. If you apply the
same test to global temperatures, the models show significant
skill.
There is a number of reasons why we think it is
inappropriate, actually, to apply that test on the national
temperature or precipitation over the course of the 20th
Century. That is, as I indicated, the models do not have all
those forcings. They did not have volcanic eruptions. We know
the U.S. climate record was affected by volcanic eruptions in
the 20th Century.
It did not have solar variability. Some of the changes were
affected by solar variability. The timing of El Ninos and North
Atlantic oscillations and other important oscillations are not
in these models when they simulate climate. They are trying to
produce the stoclastic behavior of climate, and they can't
predict the timing.
So if you are looking at small regional scales where these
effects are important in the historical record, it is going to
be very difficult to evaluate a model. That is why most
evaluations look at the global scale. They will aggregate
regions, but they will aggregate it up globally to remove a lot
of this noise and variability. When you do that, the models
that we have used and many of the other models do show
significant skill.
In fact, a recent test by Lawrence Livermore National
Laboratory looking at the annual cycle of precipitation and the
total precipitation for the last 20 years showed that the
Hadley Center model 2 that was used in the assessment exceeds
all other models, and they tested 24 models. This was part of a
model inter-comparison project and has been going on for a
number of years.
The Canadian climate model did not do as well. It wasn't an
outlier. It was in, I would say, the lower third of the
distribution of the models being used. So I think again it
depends on what kind of tests you apply, and you have to look
at the broad breadth of the scientific information that is out
there, in my opinion.
Mr. Greenwood. Dr. Michaels, you wanted to respond. Yes.
Mr. Michaels. Yes. The standard test of whether----
Mr. Greenwood. What I need you to do is you see how this
microphone points directly at my mouth. That's what you need to
do. If it is pointing over my head, you can't hear.
Mr. Michaels. The standard test of whether a model
performs, a model being a hypothesis, is a statistical test
against random numbers. Tom very adequately answered the
question, and I would like to point out what is kind of missing
from his response, which was in fact that he did replicate my
experiment and found, as I found, on 10-year averages that it
was worse than random numbers.
He did it on 1 year averages, on 5 year averages, on 10 and
on 25 and found the same thing. Now we are talking about
warming of the surface of the planet created by changes in
greenhouse gases. After that surface and mid-atmosphere warm,
that creates a change in the temperature distribution. That
creates changes in precipitation.
I think it is rather interesting to agree on this panel
that we couldn't simulate the temperature of the United States
and somehow be happy about the fact that the precipitation was
right, because it is the temperature change that drives the
precipitation change.
Here is the real problem, if you must know. We are going to
have great difficulty simulating the temperature history of the
United States with these models for one main reason. There was
a large warm-up in the United States' temperatures that
occurred before the greenhouse effect changed very much, and
then as the greenhouse gases began to ramp up into the
atmosphere in the middle part of the century, the temperature
dropped. In the latter part of the century, the temperature has
returned to levels that are near the maxima that occurred after
the large warm-up in the early 20th Century.
It is going to be very, very difficult to simulate that,
because no one really understands why the first one occurred
and why it was of such similar magnitude to the latter one,
given the large changes in the atmospheric greenhouse effect. I
am left to conclude that we could not use the models for even
assessing the annual temperature of the United States, and the
irony of this report is it then devolves into regional
assessments after having admittedly failed now with United
States temperature.
I think we need to rethink the validity of this entire
process.
Mr. Greenwood. Let me ask a question that is a bit off the
script here, but Dr. O'Brien talked about the need for a
Manhattan project. I'd like the panelists, if you would,
starting with Dr. Janetos and going right down the line, to
offer up your sense as to whether there is a lack of resources
here. Do we need to, in fact, apply governmental and/or private
sector dollars in a very significant way to create resources,
computer and intellectual, in order to get a better grip on
this?
Mr. Janetos. Mr. Chairman, I would answer your question
very briefly. Yes, we do. We have been very clear both in the
National Assessment and in subsequent publications about the
need for substantial additional research into the topics of
vulnerabilities, and then to understand what changes, in fact,
are the most plausible in the physical climate system itself.
We have had a significant research program for sometime
now, but this is one of the most challenging issues in both
underlying biology, ecology, and the physics of the climate
system that this country has had to address in environmental
science, and I believe certainly deserves additional resources
toward its investigation.
Mr. Greenwood. Dr. Karl?
Mr. Karl. Yes. I think one way to take a look at whether or
not we need additional resources is to look back at some of the
problems that we faced in the National Assessment, we attempted
to do this. There were issues related to just understanding
whether or not we had effective observations, not to simulate
what the real climate is, but to look at the changes.
You heard Dr. Pielke talk about changes in the mid-
troposphere. There are some new results coming out that
suggest, well, the increases of temperature were a little more
than we perhaps thought. It just reflects this issue of trying
to understand what is happening in the climate itself is
complex, requiring significant investment in time and
resources.
Then the issue related to the models: We were severely
constrained by the number of models that were able to simulate,
for example, just a day/night temperature. Many of the
ecosystem modelers said this was critical for them to be able
to look at the impacts further down into the century.
So it is very clear that we need the details of climate
from the observations. We need many more improvements in the
models. My sense is that there is plenty of work out there to
be done and plenty that could be very effective in helping to
do another national assessment, if we so attempt it.
Mr. Greenwood. Dr. Lashof?
Mr. Lashof. Well, I certainly agree with that. We are
investing quite a bit in the global change research program
now. Additional resources certainly would be useful, and
particularly the kind of detailed modeling center that Dr.
O'Brien suggests, I think, would be very helpful in the United
States.
I would just add to that a caution, that the goal of
furthering the research to get at many of the details that need
to be addressed should not be posed as a substitute for the
need to take action now to reduce emissions.
I would just like to quote from the Intergovernmental Panel
on Climate Change report, synthesis report from 2001, that says
that, ``The pervasiveness of inertia and the possibility of
irreversibilities in the interacting climate, ecological and
socioeconomic systems are major reasons why anticipatory
adaptation and mitigation actions are beneficial. A number of
opportunities to exercise adaptation and mitigation options may
be lost if action is delayed.''
Mr. Greenwood. Dr. O'Brien, we know what your answer is,
but perhaps you could elaborate on what you have in mind.
Mr. O'Brien. Well, I am going to brag now. I have used more
computer time than you probably imagine that a scientist and
his students can use all my life. I can say for the absolute
first time in my life I personally have adequate access to
computer time. It is through two ways.
One was when the Soviet Union surrendered, they finally
changed procurement rules in the Department of Defense, and now
in the Department of Defense they can buy computers. You know,
in 1975 the poor guys inside Department of Defense had to guess
what Kray and the other ones are going to have 8 years from
now, because that is how long it took to buy a computer.
We, fortunately, have ONR support, and I can get access to
those for some of our ocean modeling. Florida State has
invested in a large system which, as I'll brag, has put us 3, 4
in the world, and the first in universities in the United
States, and I am very happy.
We know, for example, that why didn't we have any U.S.
models? Well, there are two institutions that historically we
would look to. That is the Geophysical Dynamics Lab, NOAA's lab
in Princeton, and the National Center for Atmospheric Research,
and neither one had adequate computer things to do these kind
of models that our international partners are doing.
You know, sir, in a word I want you to remember, computers
are cheap. I find hundreds of young scientists, PhDs, working
in these labs with absolutely inadequate computers, and you
know, you figure out what the cost per manyear is for a PhD
with all the support, and the computers these days with Moore's
law operating are really, really inexpensive.
The other thing is that at NCAR I have been developing a
new climate model, and I am putting their best scientists on
it. But they want to go back to individual papers and things
like that. I really believe, to advance this, this is a
national emergency, the kind of cost that you mentioned
yourself, that climate change is going to cost this country
trillions of dollars and problems as we go down 10 to 20 years.
We need to put it in a situation where it is outside the
politics of whatever the history of that lab is, and something
where, you know, young--bright, young scientists will take this
as a challenge, that they can go there and work for a while.
You know, there is an example in our government. You know,
they are having their 30th anniversary. It is ICASE. Under
NASA, you know, they have this little think tank for numerical
modelers in other areas besides weather and climate, and it is
at Langley, and it is the NASA Administrator's budget, and it
is an absolutely beautiful thing.
They take the brightest young mathematicians that come out
of our university systems, and put them in an environment in
which they an really advance the understanding in areas like,
you know, simulating, as someone said, aircraft and simulating
other things.
So I think it is really a priority, and I really think it
is relatively cheap compared to the kind of money that we are
spending on satellite systems, observing systems, that we
really need to do this. I'm sorry to take so long.
Mr. Greenwood. That's quite all right. Dr. Pielke.
Mr. Pielke. Yes. I think there is a need to have a
redirection of this effort, but I would like to focus more on
the vulnerability perspective. That is, you start from that,
and we have to assess vulnerabilities to environmental risks,
societal risks, all kinds of risks that we can think of, and
where does climate fit within that umbrella, and then develop
plausible projections from both models, from historical record,
artificial creation of data.
This is, I think, a much more vibrant and inclusive
approach than what the National Assessment did, because if we
start from vulnerability and we find where our thresholds and
our concerns are, that is where we can spend our resources.
I think, in terms of developing better models, I would
agree with Dr. O'Brien that we actually have a lot of computer
tools available today, and we can do a lot more with these
models. I think that needs to be integrated more into the
process, some of the work with respect to land use change on
the climate system, the multiple effect that aerosols have on
cloud and precipitation.
Climate is a very complicated problem. As I said in my
testimony, I don't think that predictability may be the
ultimate goal to understanding of the climate process itself.
That is why I fall back to the vulnerability paradigm, because
that permits us to make decisions even if we don't understand
what exactly will happen in the future.
Mr. Greenwood. Dr. Michaels?
Mr. Michaels. Mr. Chairman, perhaps I spend too much time
in Washington, but it would be hard for me to imagine a panel
of scientists or agency heads saying that they didn't need the
money, and you always have to be very careful.
Mr. Greenwood. We have a predictive model that predicted
that you all would say this.
Mr. Michaels. Yes. Now having said that, let me offer
somewhat of an alternative point of view, first of all, on the
assessment. I think that it probably would have been
appropriate had there been more involvement from the State
climatologist community, because we are the people who have to
respond to the press more than anybody else, and the public,
when these reports come out. If we had had more input, I think
we would have been happier with the report.
Having said that, I might be able to simplify the problem
for you a little bit, and I am going to show you a picture. Mr.
Chairman, in absence of a picture, I'll paint you a picture.
We have a number of computer models for the behavior of the
atmosphere, and by and large, although there are a few outliers
like the Canadian model, they predict straight line increases.
They say once human warming starts from changes in the
greenhouse effect, it takes place at a constant rate. I believe
human warming has started from changes in the greenhouse
effect, because I believe that human warming has started.
Mr. Greenwood. So you are defining human warming as----
Mr. Michaels. Greenhouse warming has started as a result of
this.
Mr. Greenwood. All right.
Mr. Michaels. So perhaps what we ought to do is to
adjudicate all these straight lines. You see some of them are
going up like this. Some of them are going up like this, and
some of them are going up like this, and some of them are going
up like that. Now all the models say that once the warming
starts, it takes place at a constant rate. So why don't we just
plot the observed rate of human warming?
You know what you get when you do that? You get something
around 1.6 degrees Celsius over the next 100 years. I would
think that our research effort should be attempting to answer
the question why is the warming rate proceeding at the low end
of the range of expectations, and why has it been so constant?
I wish I could show you a chart right now to show you how
constant it has been, and I think that that is the research
question of the future.
Again, my other answer is the next time around, let's get
more of the State people in these reports, because they are the
ones who can take these reports to the public and explain them
the best.
Mr. Greenwood. Feel free to find your picture and show it
to us when you find it.
The Chair recognizes the gentleman from Florida, Mr.
Deutsch, for 10 minutes.
Mr. Deutsch. Thank you. How much confidence do we have in
the climate projects at this point in time, and then
specifically related to that, we have--You know, there's
different models and different scenarios. Can each of you
comment on what is agreed to in these different models and
scenarios? Maybe we could just go to Mr. Janetos.
Mr. Janetos. Yes, sir. In the models that we used in the
assessment itself, there was a single underlying emission
scenario. This is, in fact, a limitation of the assessment. The
scenario--The emissions scenario that we chose was one that had
been thoroughly examined internationally.
So in one sense, one of the things that was agreed quite
constant throughout the assessment was the underlying forcings
of greenhouse gas accumulations and changes in sulfates and
aerosols, for example. the models that were used----
Mr. Greenwood. Would you define forcings, because you have
all been using that, and I am not sure that Mr. Deutsch and I
understand.
Mr. Janetos. The changes in the impacts on the atmosphere
that actually cause climate to change and to vary, in an
abbreviated way. The models--All of the models that were used
in the assessment shows some warming. There was obviously--over
the U.S. There is obviously disagreement in the actual
magnitude of that warming.
They also show--They do show rather different changes in
precipitation, which Dr. Karl has referred to in his testimony.
In each case we actually--The analysis that we actually
performed was to take the changes in the models and apply those
to an interpolated dataset of the historical record of the
United States.
So the actual variability that was analyzed was drawn from
the historical record itself. We did this in order to attempt
to be conservative in our analyses, in particular with respect
to changes on intra-annual and decadal time scales. Thank you.
Mr. Karl. If I could address the question simply, there's a
number of items that I think everyone would agree on. One it is
going to get warmer, and again, as Dr. Michaels has mentioned,
the issues are how much warmer. That is why you will see in the
IPCC reports this uncertainty range, and that is why I think it
is important in these scenarios to look at that full range.
So, clearly, being warmer is part of it, and then the
implications of what happens when it is warmer, reduced snow
pack, more rain versus snow, and you can imagine what some of
those hydrological impacts might be.
The other aspect that I think most of us would agree on is
that we can only state in very general terms what we would
expect to see with precipitation: Increase in mid and high
latitude precipitation, generally globally more precipitation,
subtropics perhaps less precipitation, and that dividing line
between the subtropics and mid and high latitudes comes very
close to the United States. That is why you see that we are
very uncertain about just the exact sign of precipitation.
One thing is also, I think, in general agreement. If it is
not raining, with warmer temperatures, you generally have more
evaporation, more evapotranspiration, depending--Here is where
vegetation becomes important. So when you get down to local
scales, if vegetation begins to change as temperatures
increase, it could actually affect the amount of water that is
being evaporated.
So in the general sense, there is agreement when it's not
raining, more evaporation; but there is important regional and
local scale differences that we probably would not all agree
on.
Last, one item, that again in general all the models that
we have looked at, all the models that are available in the
literature--you can argue from thermal dynamic considerations
from some of the equations that we use in physics that, as the
globe warms, precipitation tends to fall in heavier events.
This is what all the models are projecting.
We are beginning to see this in the observations. It
doesn't occur everywhere, but more areas we are seeing than
areas we are not seeing it, and that is also reported in the
IPCC report.
So those are a number of the things, I think, that there's
some consistency that I think we might all be able to agree
upon.
Mr. Deutsch. Dr. Lashof.
Mr. Lashof. Thank you. Let me start by saying what we can't
do. Dr. Michaels has made this argument that the models are
like a table of random numbers. But the test that he has
applied is a very particular test, and it is a test that
basically says can these models predict the weather in
Philadelphia or Miami on July 25, 2010 better than a table of
random numbers.
The answer to that is no. Why? Because 2010 is only 10
years from now, and over a 10-year period natural variability,
El Ninos, volcanic eruptions that can't be predicted, the
general oscillations in heat between the atmosphere and the
ocean system are of the same magnitude as the expected overall
warming trend that's a result of adding heat trapping gases to
the atmosphere.
So over a 10-year period you don't expect to be able to do
better than simply using roughly current conditions as your
best predictor of the likely conditions then. Over a 30-year
period or a 50-year period, then the effects of human
alterations to the atmosphere dominate over these natural
changes and, when you apply that test, the models do much
better than a table of random numbers.
So that's the fundamental point. As a result of that kind
of consideration, there is agreement, again accepted by this
administration as well as the last administration, that warming
during the 21st Century will be larger than warming during the
20th Century.
Again, Dr. Michaels said, well, why don't we just take the
observed data and draw a straight line through it. That's okay.
The problem is that, when you have data with some scatter and
you take a relatively small period and you want to project out
over a long, you can draw a lot of straight lines with
different slopes, and it doesn't help you answer the question
how steep that slope is going to be. Again, that is why the
models are useful. They give us more insight into that.
Just a couple of other facts that are very robust to add to
the ones Dr. Karl just mentioned. We expect sea level rise
during the 21st Century will be significantly more rapid than
sea level rise during the 20th Century. That has obvious
implications for your State, Mr. Deutsch.
In addition, the effects on coral reefs are expected to be
very severe. The reason for that is both the increase in
temperature--where coral reefs are already threatened by high
sealable temperature events that cause coral bleaching, that
becomes much more common--plus the direct effect of increased
CO<INF>2</INF> which, as the atmosphere accumulates more carbon
dioxide, carbon dioxide increases the acidity of the ocean and
literally erodes the corals.
So if we continue to add carbon dioxide to the atmosphere,
with high confidence we can say, and the National Academy says,
that coral reefs are extremely vulnerable to being wiped out in
many areas. Those are just a couple of examples. Thank you.
Mr. O'Brien. One of the interesting things about the global
models is that some of us near my age remember the first one by
Jim Hanson from NASA GIS in which he told the Senate that we
would increase 10 degrees Fahrenheit by 2020, but he had a very
small computer. So he had no ocean in his model, and eventually
the GCMs, which were putting oceans in--The trend that I
mentioned in my report is that what I see in the models is
that, as the models keep increasing, the magnitude of the
impact out at 100 years is decreasing.
I think that Dr. Michaels' straight line--and I think there
is probably only one--is a lower bound unless something else
happens, because we might be going into an ice age, which has
nothing to do with what man is doing to the planet. In fact,
Mr. Deutsch, if you look in the back of my report, you will
find out that where you live in south Florida is warming up,
but most of Florida is actually cooling down. It is actually
cooling down.
I remind the panel that around 1880 in Savannah, Georgia,
and Jacksonville, Florida, two wonderful places, they harvested
tens of thousands of boxes of very good oranges which they
shipped to Europe and to Washington and those areas, and now if
you want to grow oranges, you have to be south of Orlando.
So, clearly, part of the southeast has certainly not
experienced this warming that some people are finding in the
data. But I believe that the models will get better, and I
believe that Dr. Pielke's ideas about vulnerability and other
effects are extremely important in order to direct the modelers
that are not in an ivory tower just doing these physical
models, and we are already working in those areas.
You know, right now in the State of Florida, actually by
using climate variability, we are actually now providing forest
fire predictions, county by county, month by month. So there's
a lot to do in applied work, and I am very pleased that we have
the support of that.
So the models will get better as the resolution gets
better. This is a known fact with weather prediction. You know,
we went from, when I was in graduate school, about 250
kilometer on side grids until now, you know, the weather
predictions are getting down to 10 kilometers on a side,
particularly at this European center that I mentioned earlier,
and their forecasts for weather are getting very, very nice,
much better than we have had in the past.
So I really believe that we need these models. You know,
also the Nation is investing a lot of new resources in the
ocean. There is a large portion of the scientific community
that believes that we also need to understand the ocean. The
ocean is the flywheel in the climate system. It is the thing
that will change, and I am sorry to tell you, Dr. Lashof, but
the ocean's pH cannot incorporate--The ocean is a very buffered
system.
Also the things about corals is somewhat a red herring.
There's later research. Remember, about 10 years ago the corals
south of Florida were dying. They blamed it all on the El Nino.
That was the era when everything was due to El Nino. In fact,
actual experiments and in the literature, published not by me,
of course, shows that, you know, a lot of this is natural, and
sometimes the bleaching is actually beneficial for the coral
for when they take their next bloom.
It's sort of like in northern Florida and Georgia, you
know, if we don't get any cooling in the winter, you don't get
any peaches. Thank you.
Mr. Pielke. Yes, sir. The fundamental hypothesis for these
models is that we can predict the future change based on
CO<INF>2</INF> and other greenhouse gases and aerosols, and not
just CO<INF>2</INF> but the radiative effect of CO<INF>2</INF>,
how it affects the greenhouse effect. But carbon dioxide has
other effects such as biogeochemical effects, and there's the
land use change that we have already mentioned.
These make it--These haven't been included in the models.
So we don't know if they have predictive ability, but it is a
necessary condition to test. As I showed in my testimony, the
current suite of models that were used in the U.S. National
Assessment have failed to replicate the atmospheric change over
the last 20 years.
The atmosphere has to warm in order to warm the surface,
and as to why the surface has warmed and the atmosphere hasn't,
that is the subject of some controversy. But some of our
initial work suggests maybe some of the surface data is not
spatially representative. We can talk about that more, if you
would like.
For south Florida specifically, we have actually published
papers on that subject, and we have shown, for example, the
July, August warming that has occurred in south Florida over
the past 80 years or so can be explained entirely by land use
change, the fact of the draining of the marshes, the draining
of the wetlands. Doesn't mean that is the only reason that it
has occurred, but we can explain it. That has not been included
in the National Assessment.
Finally, I would like to conclude this answer with just
going back to the statement of my Society of the American
Association of State Climatologists. We specifically concluded
that climate projects have not demonstrated skill in projecting
future variability in change in such important climate
conditions as growing season drought, flood producing rainfall,
heat waves, tropical cyclones, and winter storms, and these
types of events have a much more significant effect on society
than average annual global temperature trends, even if we could
predict them correctly.
Mr. Michaels. Thank you. I think, I'm sure inadvertently,
Dan misrepresented my analysis. We weren't just using 10-year
decadal averages. We were looking at 10-year running means,
1991 to 2000, 1990-1999, etcetera, on back through the
historical record.
He said that, if we had looked at 30-year averages, that
would have been important. Well, I didn't, but Tom Karl was so
interested in our analysis that he did, and he found that the
models over the U.S. for temperature, in fact, were no better
than random numbers on 25-year averages.
I would like to get back to this notion of what we know and
what we don't know. Both the House and Senate have considered--
thrown considerable resources at us, probably about $10 billion
over the years, to study this issue of climate change, and much
of it has gone toward the modeling of climate change.
Now I am going to believe that for that $10 billion we at
least got the mathematical form of those models correct. This
is the grab bag of models. I could get you a whole bunch of
others. What you see is they are straight lines in general. The
Canadian model is an outlier.
Now the reason for this is simple. It is because we are
adding carbon dioxide in the atmosphere at a slightly
exponential rate, if I could draw your attention to my hand,
slightly greater than a straight line, but the response of the
atmospheric temperature to carbon dioxide is what we call a
logarithm. It begins to damp off. If you add up an exponent and
a logarithm, you get a straight line. That is what we have
here.
As the greenhouse era began, and we can, I think, see that
when we see the cold air masses in Siberia start to warm up--
that's a real strong signal of a greenhouse.
Mr. Greenwood. When was that?
Mr. Michaels. That's about around 1970 or so this begins to
take place. We could plot the temperatures against this. I want
to show you something. Now let me finish with an analogy.
We have different weather forecasting models, and I teach
weather forecasting at University of Virginia every once in a
while, and some days the models will differ. We have the ADA
model. We have the NGM model which stands for ``no good
model.'' We have the ECMWF. We have all these models. What do
you think we tell students, for all their tuition money, when
we have all these different models forecasting slightly
different weather for the next 3 days?
We tell them to look out the window. We tell them look at
what is happening around the country, and see which model
corresponds best to reality. That is what we do for the weather
forecasting problem, and that is what this graph does for the
climate forecasting problem.
I draw your attention to the blue dots, once they start to
go up, how remarkably little they depart from the straight
lines. It's just that the computers predict different straight
lines. What has happened here--what explains this curve is not
only the addition of the logarithmic and the exponential
response, but a remarkable constant has emerged in our study of
human influence on the atmosphere, which is the amount of
carbon dioxide emitted per person is constant as population
increases.
Now we believe population is not going to increase as much
as it was. This curve is a true indicator of what is happening,
and I see absolutely no reason to believe that those constances
are going to begin to suddenly depart from reality.
Mr. Greenwood. I am going to recognize myself for an
additional 10 minutes.
Mr. Deutsch. Mr. Chairman, if I might, I have gotten a
request, a unanimous consent request, that other members be
allowed to submit statements and questions for the record.
Mr. Greenwood. Without objection, they certainly will be.
Dr. Pielke, in your testimony you described a policy
statement of the American Association of State Climatologists
which recommends that, ``Policies related to long term climate
not be based on particular predictions, but instead should
focus on policy alternatives that make sense for a wide range
of plausible scenarios.''
Does this mean State climatologists, by and large, do not
consider the National Assessment a useful tool for
policymaking?
Mr. Pielke. Well, we didn't specifically talk about the
National Assessment. We talked about the climate change issue
in general. I would think we would fall back on our comment No.
2 in our policy statement that recognizes that the models are--
or that climate prediction itself was a very complicated
problem, and that verification is also difficult, if not
impossible, because you have to wait a long period of time in
order to come up with the predictions.
I think we also recognize as State climatologists that
climate is much more complex than is implied by the U.S.
National Assessment, since they didn't, for example, include
all the human forcings; and because of that, as I said a few
minutes ago, we have concluded that there is no skill in any of
these models, the IPCC or the U.S. National Assessment, for
predicting these regional impacts of growing season, drought,
flood producing rainfall and so forth.
So even if the models did show global skill, which I don't
think they have, they certainly have not shown regional skill
as voted on by nearly a unanimous vote of our Society.
Mr. Greenwood. Thank you. Dr. Janetos, let me return to
you. You note in your testimony that the report explicitly
describes the synthesis team's scientific judgment about the
uncertainty inherent in each result. (a) Can you explain why
this effect was sufficient, given the complexities of the
undertaking, the public mindset, and the context in which the
report would be taken?
Mr. Janetos. It was certainly our hope and our intent to
signal to our readership, however wide or narrow it might have
ended up being, our judgment about the robustness and
confidence that we had in our major findings. To give you a
particular example, results that were only found in one model
run from one GCM and one ecological model, as extreme as they
might have been, were judged to be of substantial--We had
substantially less confidence in those results than findings
that were consistent amongst either climate models or ecosystem
models.
It was certainly not our intent, nor the design of this
report, to have it serve as the sole basis for national
policymaking, and it obviously is not being used as such, as a
sole basis for policymaking, which I think is wise.
Many of us have subsequently collaborated on a publication
in which we lay out our views of the scientific uncertainties
and recommend programs for addressing those, which is currently
in press in the peer reviewed literature.
Mr. Greenwood. Thank you. Mr. Karl, do you believe the
caveats about uncertainty were sufficient?
Mr. Karl. Yes, I believe that we went to great pains to
develop a lexicon, as Dr. Janetos had indicated, to try and
convey where it was clear in our minds that there was
considerably higher probability, given all the assumptions of
the scenarios that were generated, of the outcomes. Then there
were some where we tried to convey the information in the sense
that we just didn't know, and there was equal chances.
So I thought that, in fact, the assessment followed a
protocol that was begun in the first IPCC report in 1990 that
tried to give asterisks, asterisks meaning one, two, three or
four-star asterisks to try and convey some sense of confidence
that the scientists had in the outcomes that they were
expecting in the future.
It was very clear when we were writing this report, words
can be very deceiving. One individual may say likely, and it
causes a whole different set of ideas to come to mind that, you
know, maybe this is 95 percent certain. So we tried, and it is
shown in the report--tried to use those words and link them
with probabilities, not fixed probabilities but likely didn't
mean 95 percent. It was somewhere between 65 and 85, 90
percent. So we thought that this was a quite important thing to
do.
Mr. Greenwood. Any of the other panelists want to comment
on the adequacy of the caveats?
Mr. Michaels. Yes, I would, if you don't mind. It has
clearly been established here that both Tom and I agree that
there was the problem of the two driver models doing no better
than the table of random numbers, and on temperature, not on
precipitation, temperature being a very important variable for
agriculture and many of what we call the subsequent impact
models.
To use a colloquialism, that's garbage, garbage in, and
there is a transitive property of refuse when you apply it to
subsequent computer models, and that's what comes out. I have
yet to understand, I have yet to hear a justification for
proceeding along this road when the leadership knew that there
was this problem with the models.
I think they should have stopped and said, wait a minute,
we need to report back to you that we really can't go down this
road, even though we were commanded to, because we don't have
the tools. They could have come to you and said, listen--I
mean, they could have disagreed with me, that's fine--we need a
lot more money. We need a lot more support to study this
problem and to give you what is an assessment that is based
upon real numbers, not random numbers. That is my problem with
the competence in this report.
Mr. Greenwood. Thank you. Mr. Karl, can you elaborate on
the timing of model improvements in your testimony? Can models
ever provide a level of certainty needed to convince
policymakers or even the State climatologists?
Mr. Karl. First off, I would preface my comment that I
think I will try and limit my comments to how the improvements
in the models--how long it will take to narrow the
uncertainties as opposed to when State climatologists or
policymakers may choose to use them.
I think that, if you take a look at history, you can get a
good sense of how quickly we might be able to converge. If you
look at this issue that really began to become a focus of the
scientific community in the 1980's, the first models that were
generated--in fact, if you even look before that, the first
National Research Council report talked about the sensitivity
of models to doubling of carbon dioxide on the global average
temperature, and they gave an uncertainty range that stands to
this day today.
That first report done by the NRC now is over 30 years old,
and you will see that we still have the same range of
uncertainty, you know, doubling of CO<INF>2</INF>, 1.5 to 4
degrees Celsius increase in temperature globally, and then the
issues come down to, well, what is going to happen in the
specific regions.
I do see some significant improvements in the next number
of years with the use of not only global models but coupling
with regional climate models, putting in more of the regional
details, as we have discussed. So there will be some
improvements, but I would not expect that that range is going
to change substantially in the next 5 or 10 years.
If I may make one other comment with respect to some of Dr.
Michaels' statements regarding whether or not these models are
better than a table of random numbers--and again, I don't want
to turn this into a scientific debate, but the way you apply
tests to models is very important to know the framework. What's
the level playing ground?
These models that were run had one simulation. We know that
you need many simulations to adequately capture important
climate fluctuations, and we don't have that, and only if you
have many, many different ensembles, orders of hundreds of
climate model runs using the same forcings, can you hope to see
what the scope of variability might be.
These models did not include volcanic eruptions at the time
they erupted, like Mount Pinatubo, El Chechon. So again there
are--As I said in my testimony, my oral statement, there's many
different tests out there, and it's very tenuous to put too
much information on any single test.
One other issue that's come up related to the tropospheric
temperatures, mid-troposphere, that Dr. Pielke has argued show
less warming than models projected. I just wanted to point out,
if you go back to the early Sixties, we have radiosonde data
that go the early Sixties. The warming produced by the
observations and the models on a global basis are quite
consistent.
Mr. Greenwood. Dr. Michaels, you wanted to respond?
Mr. Michaels. That is true, Tom, except you know and I know
that the warming that occurred in the radiosondes--these are
the weather balloons--is a peculiar warming that shows a step
function somewhere around 1975, 1976.
In fact, if you take this weather balloon record and go
from its beginning, which depending on the record you are using
is 1956 or--or 1957 or 1948--Take the 1956 to 1975, and it is
constant--or 1976. There is no warming. Then you take the 1977
to now or to the late 20th Century, and it is constant.
There is this jump that occurred in the mid-1970's. Some
people call it the great climate shift. We have no idea what it
was. We also have no computer model. O'Brien will explain it
all. We have also no computer model that I know of for change
in greenhouse gases that says all of a sudden the tropospheric
temperature jumps.
So it is a little misleading to say, yeah, those records
match up, because the computer models are predicting a smooth
change--you saw that--in the free troposphere, and the
atmosphere isn't obeying the law as specified by the computer.
I think Tom and I are in agreement, by the way, largely. If
I were to deconstruct, and as a college professor I am forced
to do this--If I could deconstruct your answer about, well,
Michaels' test, you know, really was a little bit harsh,
because he didn't include volcanoes or something like that,
isn't Tom Saying that the models were inadequate for this
report?
Mr. Greenwood. I will let him answer that himself.
Actually, we have a pending vote. So I am going to ask the last
question of the hearing, and it is kind of a wide open
question.
That is this. The Congress and the Executive commanded that
this study be done, but I want to ask each of you to respond to
this question. If you had the power to command the Congress and
the President with regard to the policies that we should enact
and employ with regard to this entire range of global warming,
everything from resources needed to study, the policy decisions
with regard to emissions, how would you command us? Dr.
Janetos?
Mr. Janetos. Mr. Chairman, a daunting question indeed. I
think my command would be twofold. One would be to take those
actions which make sense now, not to imagine that the
uncertainty in the science acts as a break to inhibit
mitigation activities that make sense----
Mr. Greenwood. Could you give us an example of those
actions that you think we should take?
Mr. Janetos. I believe that some measure of mitigation for
greenhouse gas emissions is in order, mitigation actions that
are achievable with current technology and at reasonable cost.
I also believe quite strongly that resources and a focused
program on vulnerabilities and the sensitivities of natural
resources to changes not only in climate but to other
environmental stresses is in order. We face a changing planet.
That is very clear. Ultimately, our well-being depends on our
ability to manage those resources well.
Mr. Greenwood. Dr. Karl.
Mr. Karl. Well, one of the things that I think is most
important to consider to try and move forward on this issue is
the difficulty that we face when we try to go from discipline
to discipline to understand the important impacts and the
adaptations, the mitigation measures we might take.
There is a tremendous amount of collegial interaction that
must occur between physicists, climate scientists, ecologists,
specialists in hydrology. One of the things we found in the
National Assessment, I think, that was so valuable was, for the
first time, these communities were actually talking together.
Outputs from one model were looked to see how they might be
able to run another model. Observations from one group were
looked at how they might apply to another area.
That activity is really critical, and it is dependent on
individuals trying to forge these interactions, these
discussions. So I think one of the important messages from the
National Assessment, one area that really is important if we
expect further progress in this area, is to continue and
encourage anything we can do to encourage that dialog across
disciplines.
Most scientists get much more pats on the back by being
specialists in their own field. So without a push in that
direction, it is going to be very hard, I think, to expect
individual scientists to--although I'm not speaking for
everybody, but I think letting the system go and expecting that
to happen on its own will be difficult.
Mr. Greenwood. Dr. Lashof.
Mr. Lashof. Mr. Chairman, we know that we are adding a
thickening blanket of heat trapping pollution to the atmosphere
in CO<INF>2</INF> emissions from automobiles and power plants.
We know that that is going to cause the climate to change, and
indeed the climate has already begun the changes. I think
everybody on this panel has recognized.
The National Assessment shows that the United States is
very vulnerable in many respects. We can't predict what the
weather will be on July 25, 2030, but we can say that there are
very severe risks to the United States if we continue to add
carbon dioxide to the atmosphere at the increasing rates that
we have been.
We also know that for the last 10 years we have had a
voluntary approach to trying to limit the emissions of
greenhouse gases, and it's failed. Our emissions are going up.
So I think that the basic conclusion is pretty straightforward.
It's time for mandatory limits on emissions of carbon dioxide
and other heat trapping gases.
The House has before it the Clean Smokestack Act sponsored
by Congressmen Boehlert and Waxman that would take a big start
on that, focusing on an integrated approach to cleaning up
emissions from power plants. I think we need an energy policy
that is designed to limit carbon dioxide emissions.
Unfortunately, I believe that the policy that was passed by the
House earlier in the year moves us in the wrong direction, and
instead of, for example, strengthening efficiency standards for
automobiles that would have the result of reducing emissions of
CO<INF>2</INF> and making us less vulnerable to dependence on
foreign oil, it actually moves us in the wrong direction. It
weakens currently law.
So I think there are some very clear steps. You know, the
good news is that this is a very daunting problem, but unlike
some other problems like terrorism and poverty, I think we know
how to solve this problem, and we just really need to get to
work on it. So that would be my answer. Thank you.
Mr. Greenwood. Dr. O'Brien.
Mr. O'Brien. Mr. Chairman, I have two points here. One
point is that, besides my colleague, Dr. Pielke's, very good
points about looking to see where the vulnerabilities are so
you know where to put the emphasis on your studies, I believe
that more--that Congress should direct the scientific community
to start looking at understanding climate variability, and I
mean how we vary on the scales of annual, multi-years and
multi-decades, because these are the way that we finally get to
this straight line. I think that just looking at what is going
to happen 100 years from now is the wrong approach.
I also believe--The second point is I believe that this
changing climate variability and its understanding should be
made a national security issue and not just a domestic issue. I
feel sad to hear that we continue to focus today too much on
just what is happening in the United States, but unfortunately
with our standing in the world, you know, we are taking on
responsibility for lots and lots of parts of the world, you
know.
You see lots of efforts both in the military and the
civilian side, and I do believe that we need to think about
other places in the world. You know, if climate variability
destabilizes countries which are on the edge--and I'm not going
to mention any now--you know, that is going to cause a great
problem for our economy and our citizens. So I really believe
that we should return to the idea that the changing climate in
the future and its variability is really an important national
security issue for the United States.
Mr. Greenwood. Thank you, sir. Dr. Pielke.
Mr. Pielke. Well, first I would like to mention, I think we
should move beyond the term global warming to the more
inclusive term, which is human induced climate change; because
I think it is multi-dimensional and multi-faceted, as our
policy statement says.
In the specific policy statement of my association, there
are two bullets in there that I think address your question
specifically. The first one is that policy responses to climate
variability and change should be flexible and sensible. The
difficulty of prediction and the impossibility of verification
of predictions decades into the future are important factors
that allow for competing views of a long term climate future.
Therefore, the American Association of State Climatologists
recommends that policies related to long term climate not be
based on particular predictions but instead should focus on
policy alternatives that make sense for a wide range of
plausible climatic conditions, regardless of future climate.
Climate is always changing on a variety of time scales, and
being prepared for the consequences of this variability is a
wise policy.
Second, in our interactions with users of climate
information AASC members recognize that the Nation's climate
policies must involve much more than the discussions of
alternate energy policies. Climate has a profound effect on
sectors such as energy supply and demand, agriculture,
insurance, water supply and quality, ecosystem management, and
the impacts of national disasters.
Whatever policies are promulgated with respect to energy,
it is imperative that policymakers recognize that climate
variability and change has a broad impact on society. The
policy responses should also be broad. Thank you.
Mr. Greenwood. Dr. Michaels.
Mr. Michaels. Mr. Chairman, as a CATO scholar, I guess I am
going to have to be rational. The fact of the matter is that I
believe what we should do now is not mandate technological
programs and technologies that will not do very much about
warming.
When Mr. Gore came back from Kyoto in 1997, he asked the
government scientists to project how much warming the Kyoto
Protocol would save. The Protocol would require us to reduce
our emissions 7 percent below 1990 levels, etcetera. Let me
show you the calculation.
The solid black line is the average temperature change from
a suite of models if all the nations of the world did Kyoto.
The dashed line underneath it--if we continued business as
usual, I'm sorry. The dashed line underneath it is what happens
if all the nations of the world did Kyoto.
The change in global surface temperature exerted by Kyoto
in 50 years would be seven hundredths of a degree Celsius,
fourteen hundredths of a degree Celsius in 100 years.
If we really are concerned about this problem, I suggest
rather than mandating technologies that we specifically allow
people to retain their income to invest in the technologies of
the future that this Congress and no one on this panel can
define. One hundred years ago, the technology that ran our
society was radically different than it is today. One hundred
years from now, it will be radically different. It will be more
efficient. It must be, because that is what a market
determines.
I think the best thing to do is to allow people to invest
in those technologies, their own choice, rather than having
governments, perhaps mistakenly, invest other people's monies
in technologies that simply will not accomplish what many
people on this panel think needs to be accomplished.
I believe our change to a less carbon based economy is an
historical inevitability. All we have to do is get out of the
way.
Mr. Greenwood. You would command us to command less.
We thank all of our witnesses for your presence and your
testimony, and excuse you now. This hearing is adjourned.
[Whereupon, at 11:45 a.m., the subcommittee was adjourned.]
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