[Senate Hearing 106-1128]
[From the U.S. Government Publishing Office]
S. Hrg. 106-1128
CLIMATE CHANGE IMPACTS TO THE
UNITED STATES
=======================================================================
HEARING
before the
COMMITTEE ON COMMERCE,
SCIENCE, AND TRANSPORTATION
UNITED STATES SENATE
ONE HUNDRED SIXTH CONGRESS
SECOND SESSION
__________
JULY 18, 2000
__________
Printed for the use of the Committee on Commerce, Science, and
Transportation
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SENATE COMMITTEE ON COMMERCE, SCIENCE, AND TRANSPORTATION
ONE HUNDRED SIXTH CONGRESS
SECOND SESSION
JOHN McCAIN, Arizona, Chairman
TED STEVENS, Alaska ERNEST F. HOLLINGS, South Carolina
CONRAD BURNS, Montana DANIEL K. INOUYE, Hawaii
SLADE GORTON, Washington JOHN D. ROCKEFELLER IV, West
TRENT LOTT, Mississippi Virginia
KAY BAILEY HUTCHISON, Texas JOHN F. KERRY, Massachusetts
OLYMPIA J. SNOWE, Maine JOHN B. BREAUX, Louisiana
JOHN ASHCROFT, Missouri RICHARD H. BRYAN, Nevada
BILL FRIST, Tennessee BYRON L. DORGAN, North Dakota
SPENCER ABRAHAM, Michigan RON WYDEN, Oregon
SAM BROWNBACK, Kansas MAX CLELAND, Georgia
Mark Buse, Republican Staff Director
Ann Choiniere, Republican General Counsel
Kevin D. Kayes, Democratic Staff Director
Moses Boyd, Democratic Chief Counsel
C O N T E N T S
----------
Page
Hearing held on July 18, 2000.................................... 1
Statement of Senator McCain...................................... 1
Prepared statement........................................... 2
Prepared statement of Senator Snowe.............................. 2
Witnesses
Janetos, Dr. Anthony C., Senior Vice President for Program, World
Resources Institute............................................ 15
Joint prepared statement..................................... 6
Karl, Thomas R., Director, National Climatic Data Center,
National Environmental Satellite, Data, and Information
Service, National Oceanic and Atmospheric Administration....... 3
Joint prepared statement..................................... 6
Melillo, Dr. Jerry M., Senior Scientist, Ecosystems Center,
Marine Biological Laboratory, joint prepared statement......... 6
Schmitt, Dr. Raymond W., Senior Scientist, Woods Hole
Oceanographic Institutions..................................... 17
Prepared statement........................................... 19
Singer, Dr. S. Fred, Professor Emeritus of Environmental
Sciences, University of Virginia, and Former Director of U.S.
Weather Satellite Service...................................... 25
Prepared statement........................................... 27
Appendix
The Annapolis Center, prepared statement......................... 43
Climate Policy--from Rio to Kyoto: a Political Issue for 2000--
and Beyond, Hoover Institution Essay by S. Fred Singer......... 55
Craig, Hon. Larry E., U.S. Senator from Idaho, prepared statement 37
Robert Mendelsohn, Edwin Weyerhaeuser Davis Professor, Yale
University, School of Forestry and Environmental Studies,
letter dated July 12, 2000 to Hon. John McCain................. 56
Murkowski, Hon. Frank H., U.S. Senator from Alaska, prepared
statement...................................................... 39
Response to written questions submitted by Hon. John McCain to:
Thomas R. Karl............................................... 33
Dr. Anthony C. Janetos....................................... 34
Dr. Raymond W. Schmitt....................................... 35
Dr. S. Fred Singer........................................... 36
Rhines, Dr. Peter B., Professor, University of Washington,
prepared statement............................................. 48
CLIMATE CHANGE IMPACTS TO THE
UNITED STATES
----------
TUESDAY, JULY 18, 2000
U.S. Senate,
Committee on Commerce, Science, and Transportation,
Washington, DC.
The Committee met, pursuant to notice, at 9:32 a.m. in room
SR-253, Russell Senate Office Building, Hon. John McCain,
Chairman of the Committee, presiding.
OPENING STATEMENT OF HON. JOHN McCAIN,
U.S. SENATOR FROM ARIZONA
The Chairman. Good morning. Earlier this year, we examined
the science behind global warming as a means of defining the
problem. Today we hope to further our efforts to understanding
this issue by discussing the climate change impact on the
United States, and the National Assessment Report. Because of
the fact that at 9:45 a.m. we will begin a series of 11 votes,
which will consume the entire morning, we have a problem. We
contemplated delaying the rest of the hearing until this
afternoon, but unfortunately, a number of our witnesses were
not able to remain.
So what I would like to do is begin with opening
statements, go as long as we can, and then I will have to
adjourn the hearing and reschedule it at a later date. With a
vote every 10 minutes, I cannot keep the witnesses here for an
extended period of time. It would not be fair to the witnesses,
nor would it provide for a productive hearing.
So what I would like to do is begin with our first panel,
which is Dr. Thomas Karl, Director of the National Climatic
Data Center, National Environmental Satellite, Data, and
Information Service of NOAA, Dr. Anthony C. Janetos, Senior
Vice President for Program, World Resources Institute, Dr.
Raymond Schmitt, Senior Scientist, Woods Hole Oceanographic
Institutions, and Dr. Fred Singer, Professor Emeritus of
Environmental Sciences, University of Virginia.
I would like to express my deep apology to all of the
witnesses, particularly some who have come here from long
distances. At this time of year, we affirm Mr. Bismarck's
statement that the two things you never want to see made are
laws and sausages. These are very important hearings and very
important witnesses, and we will reschedule at the earliest
date.
Mr. Karl, we will begin with you.
[The prepared statement of Senator McCain follows:]
Prepared Statement of John McCain, U.S. Senator from Arizona
Earlier this year, we examined the science behind global warming as
a means of defining the problem. Today, we hope to further our efforts
to understand this issue by discussing the Climate Change Impact On the
United States, the National Assessment Report.
This morning we will examine, as noted in the National Assessment
Report, climate change impacts on the United States. Because the report
is currently in its 60-day public comment period which ends August 11,
we feel that this is an opportune time for the Committee to discuss
this very important matter. We hope that today's discussion will spur
others to review the document and provide comments to the White House.
I know that some have asked that today's proceeding be postponed
until later in the year. I feel this would be a mistake given the
timeframe that the Administration has laid out for completing this
report. I believe it is important to have this open discussion while
the report is still in its draft form thus providing valuable input as
it is finalized. Postponing this hearing will not afford the Committee
the opportunity to examine the report before finalization.
I look forward to hearing from our witnesses today. Although there
are many issues that need to be addressed, I hope the witness will
focus on the following: ``how can two computer models which give
different results be used to reach a consensus conclusion,'' why
federally-funded U.S. models were not selected for the study, and what
role does the ocean's dynamics play in these analyses.
As we review this document and other weather predictions, we should
keep in mind that these predictions or forecasts have very real
meanings to people and the economy. This past Sunday's edition of The
Washington Post contained an article that demonstrates the importance
of accurate weather forecasting.
The article states that the Department of Agriculture and National
Weather Service officials predicted that severe drought could cripple
the farm economy in much of the Midwest and Deep South. Secretary
Glickman warned that the lack of rain could be ``catastrophic'' to
farmers, and Jack Kelley, Director of the National Weather Service,
observed that the Midwest drought was the worst since 1955.
Farmers in the agricultural heartland took heed of the warning.
Many who were storing their 1999 yields held off putting their crops on
the market, reckoning that a drought-induced falloff in production this
year would drive up prices.
What happened was just the opposite. Timely rains and cooler-than-
predicted temperatures have offered promise of bumper crops in much of
the Midwest and other parts of the nation this fall, ensuring that
grain and soybean prices will go down for the third straight year due
to continuing oversupply.
Last week, the Department of Agriculture lowered its price
projections for corn, soybeans and wheat. The point being that a
serious, sober examination of the topic is long overdue.
Again, as noted, this is very serious business with real impacts to
the American economy and the lives and well-being of our citizens.
I welcome all of our witnesses here today.
[The prepared statement of Senator Snowe follows:]
Prepared Statement of Olympia J. Snowe, U.S. Senator from Maine
Thank you, Mr. Chairman, for calling this important hearing today
to review the public review draft for the National Assessment Report:
Climate Change Impacts on the United States, to which the public can
respond until August 11. The report is the most comprehensive so far--
giving us snapshots specifically for U.S. projections through computer
modeling to help us determine potential human impacts on the climate
change process. The Report assesses both geographic regions of the
country and its socioeconomic sectors. Whether you agree with the
different scenarios projected or not, it is a place for us to start.
In 1990, this Committee reported out legislation that was
ultimately signed into law by President George Bush, the U.S. Global
Change Research Program Act, which, among other programs, called for a
National Assessment Report to Congress. The Assessment may be an
extremely important tool when we consider the long lifetimes of the
buildup of greenhouse gases--particularly carbon dioxide--that have
already been put into the atmosphere, both manmade and natural.
Section 106 of the 1990 Public Law calls for a scientific
assessment not less frequently than every four years. Quite frankly, I
do not believe we should wait for another assessment in four years
time, as I understand the United States has made great strides in
modeling technologies and capabilities. I would like to think we are
capable of pulling on our country's best scientific modeling, as well
as the Canadian and United Kingdom models used for the Assessment in a
shorter time frame. We need the most updated research information so as
to be able to make reasoned environmental and economic policy
decisions.
In looking at the potential impacts for my state, I noted
projections that gave me great pause. Many in Maine would tell you that
if the devastating Ice Storm the Assessment Report mentions that hit
across the State in 1998 and paralyzed the state's power infrastructure
for over three weeks during bitter cold weather, is a harbinger of what
we may expect with climate change, I believe they would want Congress
to be paying more attention to the issue.
Also noted in the Report are the possible changes in Northeast
forests from conifer to deciduous trees, and the loss of an entire
tourist industry if the range of our vibrant sugar maple trees shifts
more northward into Canada; and the reduction of cold weather
recreation that is vital to the State's winter ski and snowmobile
industry.
On the brighter side, there may be the possibility for longer warm
weather recreation, already a popular summer pastime in my State, a
reduction for heating requirements in the winter--certainly good news
considering the State's energy problems last winter both with the
supply and the price of home heating oil--and the prediction for
increased crop and forest productivity.
One of my biggest concerns is the possible consequences of pest and
disease outbreaks if the climate continues to warm, implications for
both human health and our economy. According to the report, the
Northeast, because of warmer winter weather, may experience increased
incidences of diseases such as Lyme disease or West Nile encephalitis--
the same disease that was found for the first time in the New York City
area last year, which killed 7 people.
The Report says outbreaks are possible because of the increased
survival of the reservoirs of infection, such as deer and white-face
mice, and the vectors of infections, such as ticks and mosquitoes. If
true, this is very disturbing.
Also, there are also some common themes among the regions that are
noteworthy. Over 50 percent of the U.S. population resides in the
coastal zone. All coastal regions will have to adapt to changes in
shoreline characteristics and marine resources as a result of climate
change. The models do not clearly predict many of these changes and we
need to improve our oceanic databases to strengthen these models.
Even if the models are too high by 50 percent, we still need to
know who and what may be affected--both the positive and the negative--
so that informed environmental and economic decisions can be made for
mitigation and adaptation.
I look forward to the testimony and the discussion this morning,
and once again, thank Senator McCain for again bringing focus to the
issue of global climate change in this Committee as we have
jurisdiction over many of the programs concerned with climate change. I
thank the Chair.
STATEMENT OF THOMAS R. KARL, DIRECTOR, NATIONAL
CLIMATIC DATA CENTER, NATIONAL ENVIRONMENTAL
SATELLITE, DATA, AND INFORMATION SERVICE, NATIONAL
OCEANIC AND ATMOSPHERIC ADMINISTRATION
Mr. Karl. Thank you, Senator. We very much appreciate the
opportunity to comment on the National Assessment. I would like
to begin with the statement that suggests that the relevant
question in this assessment is not whether greenhouse gases are
increasing due to human activities and contributing to global
warming. Clearly they are.
The Chairman. Would you pull the microphone a little bit
closer?
Mr. Karl. Rather, the question is, what will be the amount
and rate of future warming and associated climate change
impacts and how will those changes affect human and natural
ecosystems?
In this assessment we used climate model simulations with
projected changes in greenhouse gases and aerosols comparable
to those used in the business-as-usual cases conducted by the
Intergovernmental Panel on Climate Change to assess those
impacts on a regional basis across the nation.
Our results indicate that climate change will vary widely
across the nation, those impacts will vary widely, as will our
vulnerability to climate change. What do we mean by
vulnerability? Vulnerability is defined as the magnitude of the
climate impact after consideration of adaptation measures to
lessen those impacts.
We appear to be particularly vulnerable to those impacts
affecting natural ecosystems, but less vulnerable to those
related to human-managed systems. We expect that the direct
economic vulnerability is likely to be modest during the 21st
Century for the kinds of climate scenarios we use in this
assessment, but this, too, is likely to vary considerably from
region to region.
The two principal climate scenarios for the 21st Century in
the assessment can be briefly summarized as: one scenario is
warm and wet and the other is hot and dry. Some of the gross
features include annual average temperature increases of about
5 to 10 degrees Fahrenheit. This is about five to ten times the
increase that has occurred during the 20th Century. Changes in
total precipitation are less certain.
The Chairman. Have you ever seen changes like that before?
Mr. Karl. No.
The Chairman. Increases in temperature?
Mr. Karl. No. This would be an unprecedented change this
century. In fact, the temperature increases during the 20th
Century we now believe to be larger than anything we have seen
in the last thousand years.
Changes in total precipitation are less certain, as
indicated. For example, the wetter scenario has substantial
increases in precipitation in the Southeast, about a 10- to 30-
percent increase in precipitation. The drier scenario has about
an equal decrease in precipitation.
There are other aspects of precipitation that we do have
more certainty about. For example, all the climate scenarios
and the observations suggest that more precipitation will occur
in heavy and extreme precipitation events, as opposed to the
light and moderate events.
All regions are affected by increases in the ability of the
atmosphere to evaporate water from the surface as the
temperature increases. This means that areas with marginal
increases in precipitation are likely to be more vulnerable to
more frequent extreme and severe drought. Other aspects of
extreme weather, such as hurricane tracks, local severe
weather, tornadoes, hail, et cetera, is still very uncertain.
The Chairman. I do not understand why an increase in severe
weather would be associated with climate change.
Mr. Karl. Regarding the increase in heavy and extreme
precipitation events, the best way to think about it is if you
can imagine during the winter time in Alaska when you have
precipitation, it falls in very light events. It is never very
heavy. In converse, think about in the summertime, especially
in the southern parts of the U.S., when it rains it rains very
heavily, usually in short periods. This is the kind of trend
that you will be seeing more frequently. We already see it in
the observations. That is, precipitation tends to come in
shorter bursts but heavier in magnitude.
With respect to some of the notable regional impacts around
the nation, based on scenarios we used, I will just mention a
few. In Alaska, sharp increases in temperature during the cold
season are very likely to cause continued thawing of the
permafrost, further disrupting the forest ecosystem, roads and
buildings in that area. There is already considerable evidence
in the observations that that has taken place.
In the Pacific Northwest there is likely to be more
wintertime flooding and reduced spring flooding as snow pack
decreases. Again the observations already show a significant
decrease in snow, particularly in the West. This will put added
stress on summer water supplies. Rising water temperatures will
further complicate needed fish restoration efforts.
In the Midwest, at least for the next few decades, it is
likely we will see a continued increase in agricultural
production, in large part due to the fertilization effect of
carbon dioxide on crops. We expect reductions in lake levels
are also likely, increasing the cost of transportation in the
lakes and down the rivers, ship and barge transportation.
Increased water temperatures are likely to lead to increased
eutrophication and reduced oxygen levels in lakes and rivers.
In the Northeast, climate change will very likely interact
with many existing stresses in urban areas such as air quality,
transportation, especially along the coast, due to rising sea
level and storm surges, increased heat-related stresses, and
effects on inflexible water supply systems.
Other stresses are likely to be mitigated. For example,
snow removal costs and extreme cold winter exposures.
In the Southeast, generally the South does not reap the
benefits of increased temperature for agricultural purposes,
since temperatures are already quite warm. Along the Southeast
gulf coast, inundation of coastal wetland is very likely to
increase, threatening fertile areas for marine life, migrating
birds, waterfowl.
In the hotter and drier scenario grasslands and savannahs
replace the southernmost forests in the Southeast, while the
warmer weather scenario expands the range of the southern tree
species, and large increases in the heat index (the combination
of temperature and humidity) average 10 to over 25 degrees
Fahrenheit increases that will make summer outdoor activities
quite stressful.
In the Great Plains, similar to the Midwest, higher
CO2 concentrations are likely to offset the effects
of rising temperatures, increasing agricultural yields and
forest cover for several decades. Again, the southern portions
of the Great Plains are not likely to reap these benefits.
In the West, both scenarios project a substantial increase
in precipitation, leading to a reduction in desert ecosystems,
being replaced by shrublands.
For our island States, more intense cycles of El Nino and
la nina are possible, thereby increasing stresses on existing
water supplies.
These are just a few of the impacts we discuss in the
National Assessment. I just wanted to mention that there are
many issues we are uncertain about, especially issues that are
interdependent. These could be important, even though we do not
understand them. Further assessments will need to address many
of these interdependencies.
Thank you for the opportunity to make an opening statement.
[The joint prepared statement of Mr. Karl, Dr. Melillo, and
Dr. Janetos follow:]
Joint Prepared Statement of Thomas R. Karl, Director, National Climatic
Data Center, National Environmental Satellite, Data, and Information
Service, National Oceanic and Atmospheric Administration; Dr. Jerry M.
Melillo, Senior Scientist, Ecosystems Center, Marine Biological
Laboratory; and Anthony C. Janetos, Senior Vice President for Program,
World Resources Institute
We are very pleased to have the opportunity to address the Senate
Committee on Commerce, Science, and Transportation on the topic of the
potential impacts of climate variability and change on the U.S. Our
draft assessment report, Climate Change Impacts on the United States:
the Potential Consequences of Climate Variability and Change was
released for a 60 day public comment period on Monday, June 12. It is
an extensive synthesis of the best available scientific information on
this important topic.
There are three questions about climate change that dominate
discussions of this important topic. How much climate change is going
to occur? What will happen as a result? What can countries do about it?
There are obviously heated political opinions about each of these, but
the issues are real, and it is critical to understand the underlying
scientific knowledge about each if sound decisions are to be made. The
assessment report focuses on the second of these questions.
A national assessment of the potential impacts of climate change
was called for in the 1990 legislation that established the U.S. Global
Change Research Program (USGCRP). For several years, the research
program focused on developing the basic scientific knowledge that the
international scientific assessment process overseen by the
Intergovernmental Panel on Climate Change (IPCC) depends on. The IPCC
was jointly established by the World Meteorological Organization and
the United Nations Environmental Programme in 1988. As scientific
research has provided compelling evidence that climate change is in
fact occurring, it has become increasingly clear that there is a need
to understand what is at stake for natural resources and human well-
being in the U.S. In response to this need, in 1998, Dr. John H.
Gibbons, then Science Advisor to the President, requested the USGCRP to
undertake the national assessment originally called for in the
legislation. Dr. Gibbons asked the USGCRP to investigate a series of
important questions:
What are the current environmental stresses and issues for
the United States that form a backdrop for additional impacts
of climate change?
How might climate change and variability exacerbate or
ameliorate existing problems?
What are the priority research and information needs that
can better prepare policy makers for making wise decisions
related to climate change and variability? What information and
answers to what key questions could help decision-makers make
better-informed decisions about risk, priorities, and
responses? What are the potential obstacles to information
transfer?
What research is most important to complete over the short
term? Over the long term?
What coping options exist that can build resilience to
current environmental stresses, and also possibly lessen the
impacts of climate change? How can we simultaneously build
resilience and flexibility for the various sectors considering
both the short and long-term implications?
What natural resource planning and management options make
most sense in the face of future uncertainty?
What choices are available for improving our ability to
adapt to climate change and variability and what are the
consequences of those choices? How can we improve contingency
planning? How can we improve criteria for land acquisition?
A variety of efforts emerged in response to Dr. Gibbons' charge.
Over twenty workshops were held around the country, involving
academics, business-people representing a range of industries including
manufacturing, power generation and tourism, and people who work
closely with land and water ecosystems including resource managers,
ranchers, farmers, foresters and fishermen. Each workshop identified a
range of issues of concern to stakeholders in those regions, many of
them quite unrelated to climate change, per se. Most workshops were
followed by the initiation of scientific, university-led regional
studies, some of which have finished their work, and others of which
are ongoing.
In addition to these kind of ``bottom-up'' efforts, it was decided
that it was also necessary to create a national-level synthesis of what
is known about the potential for climate impacts for the U.S. as a
whole, addressing the issues identified in the regional workshops and
national studies. This synthesis obviously needed to build on the work
that had begun to emerge from the subsequent regional and national
studies, but also to draw on the existing scientific literature and
analyses done with the most up-to-date ecological and hydrological
models and data that could be obtained. The National Assessment
Synthesis Team (NAST) was established by the National Science
Foundation as an independent committee under the Federal Advisory
Committee Act (FACA) specifically in order to carry out this second
step. This committee is made up of experts from academia, industry,
government laboratories, and non-governmental organizations (NGO's)
(membership list is Attachment 1). In order to ensure openness and
independence, all meetings of the NAST have been open to the public,
all documents discussed in its meetings are available through the
National Science Foundation, as are all the review comments already
received and responses to them. This is perhaps out of the ordinary for
a scientific study; but most scientific studies do not focus on issues
of such broad and deep implications for American society, and about
which there is such heated rhetoric.
The NAST's first action was to publish a plan for the conduct of
the national synthesis. In addition, five issues (agriculture, water,
forests, health, and coastal and marine systems), out of the many
identified, were later selected by the National Synthesis Assessment
Team (NAST) to be topics for national studies. Carrying out this plan
has been a major undertaking. The end result has been the production of
a comprehensive two-volume National Assessment Report, available to the
public for a 60-day comment period. The ``Foundation'' volume is more
than 600 pages long, with more than 200 figures and tables, with
analyses of the five national sectors, and 9 regions that together
cover the entire U.S. It is extensively referenced, and a commitment
has been made that all sources used in its preparation are open and
publicly available. The ``Overview'' volume is about 150 pages long,
written in a style that is more accessible to the lay public, and
summarizes the Foundation in a way that we hope will be understandable
and informative, and which we are confident is scientifically sound.
Both documents have already been through extensive review. At the end
of 1999, two rounds of technical peer review were undertaken, and
during the past spring, an additional review by about 20 experts
outside the assessment process was undertaken. Over 300 sets of
comments have been received from scientists in universities, industry,
NGO's, and government laboratories. The responses to all external
comments have been described in comprehensive review memorandums. We
are now in the final stage of the process, a 60 day public comment
period specifically requested by Congress, after which final revisions
will be done and the report submitted to the President and Congress, as
called for in the original legislation.
In order to ensure that the NAST has undertaken its charge well, an
oversight panel was also established through the offices of the
President's Council of Advisors on Science and Technology (membership
list is Attachment 2). The oversight panel is chaired by Dr. Peter
Raven, Director of the Missouri Botanical Garden and recently retired
Home Secretary of the National Academy of Sciences, and Dr. Mario
Molina, Professor of Atmospheric Chemistry at MIT, and recent Nobel-
prize winner for his research on stratospheric ozone depletion. Its
membership, like the NAST's, is drawn from academia, industry, and
NGO's. It has reviewed and approved of the plans for the assessment,
reviewed each draft of the report, and reviewed the response of the
NAST to all comments.
What have been the results of this extraordinarily open process?
What assumptions drive the analysis? What conclusions have been
reached?
It is important to realize that the national assessment does not
attempt to predict exactly what the future will hold for the U.S. It
has examined the potential implications of two primary climate
scenarios, each based on the same assumptions about future ``business
as usual'' global emissions of greenhouse gases that the IPCC has used
for many of its analyses. The two climate scenarios were based on
output from two different global climate models used in the IPCC
assessment. They are clearly within the range of global annual average
temperature changes shown by many such models, one near the low and one
near the high end of the range. Both exhibit warming trends for the
U.S. that are larger than the global average (Attachment 3). This is
not surprising. For many years, one of the most robust results of
global climate models has been that greater warming is expected in more
northerly latitudes, and that land surfaces are expected to warm more
than the global average. We have used assumptions that are entirely
consistent with those used by the IPCC.
These climate scenarios describe significantly different futures
that are all scientifically plausible, given our current understanding
of how the climate system operates. As importantly, they describe
separate baselines for analysis of how natural ecosystems, agriculture,
water supplies, etc. might change as a result. In order to investigate
such changes, i.e. the potential impacts of climate changes, the report
relies on up-to-date models, on empirical observations from the
literature, on investigations of how these systems have responded to
climate variability that has been observed over the past century in the
U.S., and on the accumulated scientific knowledge that is available
about the sensitivities of resources to climate, and about how the
regions of the U.S. have and potentially could respond.
One additional important point about the scenarios should be
mentioned. The report does not ``merge'' the results of models that
disagree; it explicitly avoids doing so. The best example of this is in
the analysis of potential changes in precipitation, where the two
models used to create the scenarios give quite different results for
some areas of the U.S. We have chosen to highlight these differences
and explain that regional-scale precipitation projections are much more
uncertain compared with temperature, rather than attempting to merge
the results or guess which is more likely. The knowledge that the
direction of precipitation change in some areas is quite uncertain is
valuable for planning purposes, and clearly represents an important
research challenge. There is however, consistency among models and
observations on other aspects of precipitation changes. For example,
both models and observations show an increase in the proportion of
precipitation derived from heavy and extreme events as the climate
warms (Attachment 4). So, both types of information are pertinent to
help with the identification of potential coping actions. In this
respect, the report follows the procedure that the IPCC itself uses for
its global impacts reports, each of which examines the potential
impacts for entire continents.
The U.S. national assessment presents the results for each scenario
clearly, and then takes the important additional step of explicitly
describing the NAST's scientific judgment about the uncertainty
inherent in each result. Those results that are viewed to be robust are
described in more terms; those viewed to be the result of poorly
understood or unreconciled differences between models are described in
more circumspect language. The lexicon of terms used to denote the
NAST's greater or lesser confidence is explicitly described in the
beginning of the Overview report. This helps ensure that the report
does not mask important results by thoughtlessly merging models, or
overstating the scientific capability for assessing potential impacts.
Finally, the report begins to identify possible options for adaptation
to this changing world. It does not do a complete analysis of the
costs, benefits, or feasibility of these options however, which is a
necessary next step for developing policies to address these issues.
The report's draft key findings (as more fully described in
Attachment 5) present important observations for all Americans:
1. Increased warming. Assuming continued growth in world
greenhouse gas emissions, the climate models used in this Assessment
project that temperatures in the U.S. will rise 5-10+F (3-6+C) on
average in the next 100 years.
2. Differing regional impacts. Climate change will vary widely
across the U.S. Temperature increases will vary somewhat from one
region to the next. Heavy and extreme precipitation events are likely
to become more frequent, yet some regions will get drier. The potential
impacts of climate change will also vary widely across the nation.
3. Vulnerable ecosystems. Ecosystems are highly vulnerable to the
projected rate and magnitude of climate change. A few, such as alpine
meadows in the Rocky Mountains and some barrier islands, are likely to
disappear entirely, while others, such as forests of the Southeast, are
likely to experience major species shifts or break up. The goods and
services lost through the disappearance or fragmentation of certain
ecosystems are likely to be costly or impossible to replace.
4. Widespread water concerns. Water is an issue in every region,
but the nature of the vulnerabilities varies, with different nuances in
each. Drought is an important concern in every region. Floods and water
quality are concerns in many regions. Snowpack changes are especially
important in the West, Pacific Northwest, and Alaska.
5. Secure food supply. At the national level, the agriculture
sector is likely to be able to adapt to climate change. Overall, U.S.
crop productivity is very likely to increase over the next few decades,
but the gains will not be uniform across the nation. Falling prices and
competitive pressures are very likely to stress some farmers.
6. Near-term increase in forest growth. Forest productivity is
likely to increase over the next several decades in some areas as trees
respond to higher carbon dioxide levels. Over the longer term, changes
in larger-scale processes such as fire, insects, droughts, and disease
will possibly decrease forest productivity. In addition, climate change
will cause long-term shifts in forest species, such as sugar maples
moving north out of the U.S.
7. Increased damage in coastal and permafrost areas. Climate
change and the resulting rise in sea level are likely to exacerbate
threats to buildings, roads, power lines, and other infrastructure in
climatically sensitive places, such as low-lying coastlines and the
permafrost regions of Alaska.
8. Other stresses magnified by climate change. Climate change
will very likely magnify the cumulative impacts of other stresses, such
as air and water pollution and habitat destruction due to human
development patterns. For some systems, such as coral reefs, the
combined effects of climate change and other stresses are very likely
to exceed a critical threshold, bringing large, possibly irreversible
impacts.
9. Surprises expected. It is very likely that some aspects and
impacts of climate change will be totally unanticipated as complex
systems respond to ongoing climate change in unforeseeable ways.
10. Uncertainties remain. Significant uncertainties remain in the
science underlying climate-change impacts. Further research would
improve understanding and predictive ability about societal and
ecosystem impacts, and provide the public with useful information about
adaptation strategies.
Given these findings it is clear that climate impacts will vary
widely across the Nation, as one would expect for a country as large
and ecologically diverse as the U.S. Natural ecosystems appear to be
highly vulnerable to climate changes of the magnitude and rate which
appear to be likely; some ecosystems surprisingly so. The potential
impacts on water resources are an important issue in every region
examined, although the nature of the concern is very different for the
mountainous West than for the East. The potential for drought is a
concern across the country. The nation's food supply appears secure,
but there are very likely to be regional gains and losses for farmers,
leading to a more complex picture on a region-by-region basis. Forests
are likely to grow more rapidly for a few decades because of increasing
carbon dioxide concentrations in the atmosphere, but it is unclear
whether those trends will be maintained as the climate system itself
changes, leading to other disturbances such as fire and pest outbreaks.
However, the climate change itself will, over time, lead to shifts in
the tree species in each region of the country, some of them
potentially quite profound. Coastal areas in many parts of the U.S. and
the permafrost regions of Alaska are already experiencing disruptions
from sea-level rise and recent regional warming; these trends are
likely to accelerate. Climate change will very likely magnify the
cumulative impacts of other environmental stresses about which people
are already concerned, such as air and water pollution, and habitat
destruction due to development patterns. There are clearly links
between human health, current climate, and air pollution. The future
vulnerability of the U.S. population to the health impacts of climate
change depends on our capacity to adapt to potential adverse changes.
Many of these adaptive responses are desirable from a public health
perspective irrespective of climate change. Future assessments need to
consider climate change in the context of the suite of environmental
stresses that we all face. Perhaps most importantly, the report
acknowledges very clearly that scientific uncertainties remain, and
that we can expect surprises as this uncontrolled experiment with the
Earth's geochemistry plays out over the coming decades.
We hope that the public comment period will indeed result in a
broad discussion of this draft report. This is, after all, a topic of
immense importance and broad significance for Americans. We invite
those with the interest to do so to participate by obtaining the
current draft (www.usgcrp.gov), and to submit their comments, concerns,
and criticisms. Our interest is in being as open and transparent as
possible about what we have concluded, the scientific integrity of the
results, and why we think they are important for us all.
Attachment 1
National Assessment Synthesis Team Members
Jerry M. Melillo, Co-chair
Ecosystems Center
Marine Biological Laboratory
Anthony C. Janetos, Co-chair
World Resources Institute
Thomas R. Karl, Co-chair
NOAA National Climatic Data Center
Robert Corell (from January 2000)
American Meteorological Society and
Harvard University
Eric J. Barron
Pennsylvania State University
Virginia Burkett
USGS, National Wetlands Research
Center
Thomas F. Cecich
Glaxo Wellcome, Inc.
Katharine Jacobs
Arizona Department of Water
Resources
Linda Joyce
USDA Forest Service
Barbara Miller
World Bank
Edward A. Parson (until January 2000)
M. Granger Morgan Harvard University
Carnegie Mellon University
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
Robert White
University Corporation for Atmospheric Research, and Washington,
Advisory Group
Attachment 3
Simulation of decadal average changes in temperature from leading
climate models based on historic and projected changes in CO2
and sulfate atmospheric concentrations. The heavy red and black lines
indicate the primary models chosen for use by the National Assessment.
For the 21st century the projected global temperature increase for the
Hadley model is 4.9+F and 7.4+F for the Canadian model. The model with
the smallest projected increase of global temperature is the Climate
System Model at 3.6+F. By comparison, the projected increase in
temperature for the 21st century over the contiguous U.S. is: Canadian,
9.4+F; Hadley, 5.5+F; and the Climate System Model, 4.0+F.
------------------------------------------------------------------------
Global USA
------------------------------------------------------------------------
Hadley 4.9F 5.5F
Canadian 7.4F 9.4F
CSM 3.6F 4.0F
------------------------------------------------------------------------
Attachment 4
These graphs of precipitation for the contiguous U.S. show both
observed changes during the 20th Century and projected changes for the
21st Century based on the Canadian Global Climate Model (Version 1) and
the Hadley Climate Model (Version 2). As the charts demonstrate, the
largest increases have been and are projected to be in the heaviest
precipitation events, the days already receiving large amounts of
precipitation.
Attachment 5
Summary
Large impacts in some places. The impacts of climate change will be
significant for Americans. The nature and intensity of impacts will
depend on the location, activity, time period, and geographic scale
considered. For the nation as a whole, direct economic impacts are
likely to be modest. However, the range of both beneficial and harmful
impacts grows wider as the focus shifts to smaller regions, individual
communities, and specific activities or resources. For example, while
wheat yields are likely to increase at the national level, yields in
western Kansas, a key U.S. breadbasket region, are projected to
decrease substantially under the Canadian climate model scenario. For
resources and activities that are not generally assigned an economic
value (such as natural ecosystems), substantial disruptions are likely.
Multiple-stresses context. While Americans are concerned about
climate change and its impacts, they do not think about these issues in
isolation. Rather they consider climate change impacts in the context
of many other stresses, including land-use change, consumption of
resources, fire, and air and water pollution. This finding has profound
implications for the design of research programs and information
systems at the national, regional, and local levels. A true partnership
must be forged between the natural and social sciences to more
adequately conduct assessments and seek solutions that address multiple
stresses.
Urban areas. Urban areas provide a good example of the need to
address climate change impacts in the context of other stresses.
Although large urban areas were not formally addressed as a sector,
they did emerge as an issue in most regions. This is clearly important
because a large fraction of the U.S. population lives in urban areas,
and an even larger fraction will live in them in the future. The
compounding influence of future rises in temperature due to global
warming, along with increases in temperature due to local urban heat
island effects, makes cities more vulnerable to higher temperatures
than would be expected due to global warming alone. Existing stresses
in urban areas include crime, traffic congestion, compromised air and
water quality, and disruptions of personal and business life due to
decaying infrastructure. Climate change is likely to amplify some of
these stresses, although all the interactions are not well understood.
Impact, adaptation, and vulnerability. As the Assessment teams
considered the negative impacts of climate change for regions, sectors,
and other issues of concern, they also considered potential adaptation
strategies. When considered together, negative impacts along with
possible adaptations to these impacts define vulnerability. As a
formula, this can be expressed as vulnerability equals negative impact
minus adaptation. Thus, in cases where teams identified a negative
impact of climate change, but could not identify adaptations that would
reduce or neutralize the impact, vulnerability was considered to be
high. A general sense emerged that American society would likely be
able to adapt to most of the impacts of climate change on human systems
but that the particular strategies and costs were not known.
Widespread water concerns. A prime example of the need for and
importance of adaptive responses is in the area of water resources.
Water is an issue in every region, but the nature of the
vulnerabilities varies, with different nuances in each. Drought is an
important concern in every region. Snowpack changes are especially
important in the West, Pacific Northwest, and Alaska. Reasons for the
concerns about water include increased threats to personal safety,
further reduction in potable water supplies, more frequent disruptions
to transportation, greater damage to infrastructure, further
degradation of animal habitat, and increased competition for water
currently allocated to agriculture.
Health, an area of uncertainty. Health outcomes in response to
climate change are highly uncertain. Currently available information
suggests that a range of health impacts is possible. At present, much
of the U.S. population is protected against adverse health outcomes
associated with weather and/or climate, although certain demographic
and geographic populations are at greater risk. Adaptation, primarily
through the maintenance and improvement of public health systems and
their responsiveness to changing climate conditions and to identified
vulnerable subpopulations should help to protect the U.S. population
from adverse health outcomes of projected climate change. The costs,
benefits, and availability of resources for such adaptation need to be
considered, and further research into key knowledge gaps on the
relationships between climate/weather and health is needed.
Vulnerable ecosystems. Many U.S. ecosystems, including wetlands,
forests, grasslands, rivers, and lakes, face possibly disruptive
climate changes. Of everything examined in this Assessment, ecosystems
appear to be the most vulnerable to the projected rate and magnitude of
climate change, in part because the available adaptation options are
very limited. This is important because, in addition to their inherent
value, they also supply Americans with vital goods and services,
including food, wood, air and water purification, and protection of
coastal lands. Ecosystems around the nation are likely to be affected,
from the forests of the Northeast to the coral reefs of the islands in
the Caribbean and the Pacific.
Agriculture and forestry likely to benefit in the near term. In
agriculture and forestry, there are likely to be benefits due to
climate change and rising CO2 levels at the national scale
and in the short term under the scenarios analyzed here. At the
regional scale and in the longer term, there is much more uncertainty.
It must be emphasized that the projected increases in agricultural and
forest productivity depend on the particular climate scenarios and
assumed CO2 fertilization effects analyzed in this
Assessment. If, for example, climate change resulted in hotter and
drier conditions than projected by these scenarios, both agricultural
and forest productivity could possibly decline.
Potential for surprises. Some of the greatest concerns emerge not
from the most likely future outcomes but rather from possible
``surprises.'' Due to the complexity of Earth systems, it is possible
that climate change will evolve quite differently from what we expect.
Abrupt or unexpected changes pose great challenges to our ability to
adapt and can thus increase our vulnerability to significant impacts.
A vision for the future. Much more information is needed about all
of these issues in order to determine appropriate national and local
response strategies. The regional and national discussion on climate
change that provided a foundation for this first Assessment should
continue and be enhanced. This national discourse involved thousands of
Americans: farmers, ranchers, engineers, scientists, business people,
local government officials, and a wide variety of others. This unique
level of stakeholder involvement has been essential to this process,
and will be a vital aspect of its continuation. The value of such
involvement includes helping scientists understand what information
stakeholders want and need. In addition, the problem-solving abilities
of stakeholders have been key to identifying potential adaptation
strategies and will be important to analyzing such strategies in future
phases of the assessment.
The next phase of the assessment should begin immediately and
include additional issues of regional and national importance including
urban areas, transportation, and energy. The process should be
supported through a public-private partnership. Scenarios that
explicitly include an international context should guide future
assessments. An integrated approach that assesses climate impacts in
the context of other stresses is also important. Finally, the next
assessment should undertake a more complete analysis of adaptation. In
the current Assessment, the adaptation analysis was done in a very
preliminary way, and it did not consider feasibility, effectiveness,
costs, and side effects. Future assessments should provide ongoing
insights and information that can be of direct use to the American
public in preparing for and adapting to climate change.
The Chairman. Thank you for being here.
Dr. Janetos.
STATEMENT OF DR. ANTHONY C. JANETOS, SENIOR VICE PRESIDENT FOR
PROGRAM, WORLD RESOURCES INSTITUTE
Dr. Janetos. Mr. Chairman, thank you for the opportunity to
discuss the national assessment of potential impacts of climate
change in the U.S.
There are really three questions about climate change that
have dominated many of the public and scientific discussions:
first, how much climate change is going to occur, second, what
might happen as a result, and third, what can countries do
about it?
The purpose of the national assessment is to focus only on
the second of these questions. That is, to address the question
of, so what, with our best understanding of the underlying
science, and then to address the questions of major
uncertainties in order to make well-reasoned recommendations
for future research.
The national assessment was called for in the original
enabling legislation in 1990 for the U.S. global change
research program. In 1997, Dr. John Gibbons, then Science
Advisor to the President, requested the global change research
program to undertake the national assessment focusing on
understanding other environmental stresses and issues within
which climate change impacts might occur, whether climate
change and variability might exacerbate or ameliorate existing
problems, what options for coping might exist, and what
research is most important to complete over both the short and
the longer term.
A variety of efforts emerged in response to Dr. Gibbons'
charge. First was a substantial bottom-up effort. Over 20
workshops were held around the country, involving a broad range
of stakeholders, academics, farmers and ranchers,
businesspeople, land managers, people from every walk of life.
Each workshop identified a range of issues of concern
within their regions. Many of these were followed by the
initiation of scientific studies, some of which have finished
their work and have been published, others of which are
ongoing.
At the same time, it was thought to be necessary to create
a companion but independent effort to create a national level
synthesis of what is known for the U.S. as a whole, addressing
the issues that were raised in workshops, and addressing issues
that have been raised in national studies of several important
sectors.
This national study was viewed to build on work that has
been done and published, on the published scientific
literature, and on analyses that were to be done with the most
up-to-date environmental data and models that could be
obtained. All sources that were used in the national assessment
and the national study were to be documented and to be
available so that this study would present the best snapshot at
this time of our understanding, using the best available
information.
The national assessment synthesis team, which Mr. Karl, Dr.
Melillo and I co-chair, was chartered under the Federal
Advisory Committee Act specifically to carry out the national
study. Its membership is drawn from academic and research
institutions from industry, from nongovernmental organizations,
and government research laboratories.
The first thing that we did was to publish a plan for the
conduct of the national synthesis and select five issues for
national analysis in addition to the work which Tom has just
described on the different regions of the U.S. This plan was
published in 1998 and has been available on the Internet.
The products of our work is now in two volumes. The first
of these we call the foundation volume. It is over 600 pages
long, with more than 200 figures and tables. It is extensively
referenced and, as I mentioned, we have made the commitment
that all of the sources, of which there are thousands used in
it, are documented and are available. These are basically the
same guidelines as the Intergovernmental Panel on Climate
Change has used for the accessibility of source material.
The second volume we have called the overview. It is
written more in a style for the general public. It is
substantially shorter, about 150 pages long and extensively
illustrated, and is a summary of the foundation document.
Both of these volumes have already undergone significant
review. At the end of 1999 and the beginning of this year we
went through two rounds of technical peer review. Subsequent to
that, this past spring we went through an additional review by
about 20 independent experts. We have received over 300 sets of
comments and have made a commitment to document our responses
to external comments that we have received.
In addition, we have written an overview memo summarizing
our responses to major comments. We are now approximately half-
way through a 60-day public comment period that was
specifically requested by the Congress. When it ends, we
anticipate responding to the additional comments we will have
received, as we have done before, and putting the report in
final form in order to be submitted to the President and
Congress, as called for in the original legislation.
Throughout, the national assessment synthesis team has been
the beneficiary of oversight review and guidance from an
oversight panel which was established through the offices of
the President's Council of Advisors on Science and Technology,
chaired by Dr. Peter Raven and Dr. Mario Melina.
One thing I would like to emphasize in closing is that it
is important to remember that the national assessment does not
attempt to predict exactly what the future will hold for the
U.S. It has examined the potential implications of two primary
climate scenarios, but has used many other data sets as well.
That is, it uses our best scientific understanding of
ecosystems, hydrologic systems, agriculture, forestry, and so
on, to explore the different consequences of scientifically
plausible futures.
We explicitly discuss uncertainty in the underlying
science. In fact, throughout the assessment we have
consistently used language describing our scientific confidence
in the results and findings so that the reader can understand
when we are very confident of our findings and when we are less
so.
Thank you very much.
The Chairman. Thank you very much. Dr. Schmitt.
STATEMENT OF DR. RAYMOND W. SCHMITT, SENIOR SCIENTIST, WOODS
HOLE OCEANOGRAPHIC INSTITUTIONS
Dr. Schmitt. Thank you, Mr. Chairman. I am a physical
oceanographer. In the past 25 years I have averaged about 1
month a year at sea on research cruises. In the past 10 years I
have averaged about 1 month a year working on committees
concerned with the role of the oceans in climate.
The thrust of my statement is that the oceans have a very
important role to play in climate, and that we are not doing a
very good job at either modeling the role of the oceans in
climate predictions, nor are we properly monitoring the state
of the ocean in order to make these predictions possible.
In the past few years oceanographers have done a large-
scale survey of the state of the world ocean. We called it the
World Ocean Circulation Experiment. It was funded by the
National Science Foundation, and what we found was quite
interesting.
In most areas--not all, but in most areas, deep waters had
warmed significantly since the last time a major survey had
been done in the fifties, so we are seeing global warming in
the ocean. It is real, and we are finding it in the ocean and,
in fact, the fact that we find it so deep in the ocean has been
a surprise for many climate modelers, because the models they
use have a very slow responding ocean. It is more like lava or
concrete than the water that we know.
So oceanographers have a very different view of the ocean.
We see a more active agent of climate change.
The Chairman. Why would it warm in----
Dr. Schmitt. So deep?
The Chairman. Yes.
Dr. Schmitt. Well, it is quite interesting. The ocean
interacts with the atmosphere at high latitudes, and the water
can sink quite deeply. Up in the Labrador Sea, up in the seas
off Greenland and Iceland, we call this deep convection, and
this deep convection is how the ocean changes temperature, how
it gives heat to the atmosphere and changes its own internal
temperature, and this whole process--we call it the
thermohaline circulation--is very important to transporting
heat to high latitudes, for keeping Europe warm. The fact that
England has a very moderate climate is due to this thermohaline
circulation.
Well, one of the very exciting things that the
paleoceanographers have found is that this circulation shut off
at times in the past, when that water got too fresh. At the end
of the last glaciation, about 12,000 years ago, there was a lot
of fresh water coming from the melting glaciers. It shut off
thermohaline circulation because adding fresh water makes the
water lighter and it cannot sink, so then no heat was carried
northward, Europe got very cold, and the ice ages came back for
about 1,000 years.
The striking thing is that this change happened in a couple
of decades, in the data that they have obtained from the ice
core and in the sedimentary record at the bottom of the ocean.
Some climate models predict an increase in high latitude
rainfall due to the global warming. Warm air carries more water
than cold air, and they have projected a shutdown in this
thermohaline circulation. That would be a very significant
change that could occur very rapidly.
Now, the other thing that we found in the last few years is
that the ocean has certain temperature patterns that lock in
specific climate phenomena. We all know about El Nino and la
nina. That is warm water sloshing back and forth in the
Pacific. Well, there is another oscillation called the North
Atlantic oscillation, that seems to be controlled by the
patterns of warm water moving around the North Atlantic.
We are at the stage technologically where we can make
better measurements of these deep temperature patterns in the
ocean with autonomous probes, floats that are like weather
balloons for the ocean. They drift at depth, they inflate a
small bladder every 10 days, come to the surface and obtain a
profile of temperature and salinity on the way up, send that
data to a satellite, and then resubmerge for another 10-day
drift.
From this we get the heat content of the ocean, we find out
its salt content, and therefore whether it is likely to
continue deep convecting in the winter. These things will help
us to gain the ability to predict climate for 5 to 10 years in
advance. We find this a very exciting research possibility.
The Chairman. What are you finding out?
Dr. Schmitt. Well, the hope that we are holding out is that
when we have enough data coming in from these new observation
systems, and enough understanding of these processes, that we
will be able to predict climate with greater confidence than we
have now. Right now there is a great deal of uncertainty about
all of these modes of operation.
The Chairman. When will you be able to start making these
predictions?
Dr. Schmitt. Prediction is a dangerous game. There is a
program called Argo we are trying to get funded.
The Chairman. Yes.
Dr. Schmitt. We hope to have that in place in full
operation in about 5 years, and I would think it would really
start to have a significant effect on climate predictions 5
years from now.
That is the basic thrust of my statement, and I thank you
for the opportunity to present this to the Committee.
[The prepared statement of Dr. Schmitt follows:]
Prepared Statement of Dr. Raymond W. Schmitt, Senior Scientist,
Woods Hole Oceanographic Institutions
The Ocean's Role in Climate
My name is Raymond Schmitt, I am a Senior Scientist in the
Department of Physical Oceanography at the Woods Hole Oceanographic
Institution. My research interests include the ocean's role in climate,
small-scale mixing processes, the global water cycle, and
instrumentation for a global ocean observing system. I have served on a
number of national and international committees concerned with climate,
including the Atlantic Climate Change Program Science Working Group,
the Ocean Observing System Development Panel, and the Climate
Variability (CLIVAR) Science Steering Group, and am a contributing
author to the IPCC Third Assessment Report.
The thrust of my comments today is that the crucial role of the
oceans in climate has not been sufficiently acknowledged in most
research on climate change to date, including the National Climate
Assessment Report under discussion here. It was a tradition of the
climate modeling community to treat the ocean as a shallow swamp; a
source of moisture but playing no role in heat transport and storage.
We now know this to be a significant error, the oceans are an equal
partner with the atmosphere in transporting heat from the equator to
the poles, and a reservoir of heat and water that overwhelmingly dwarfs
the capacity of the atmosphere.
A few facts about
The Oceans:
Cover 70% of the surface of the Earth.
Have 1,100 times the heat capacity of the atmosphere
(99.9% of the heat capacity of the Earth's fluids)
Contain 90,000 times as much water as the atmosphere
(97% of the free water on the planet)
Receive 78% of global precipitation
A quote from Arthur C. Clarke gets it right:
``How inappropriate to call this planet Earth when clearly it is
Ocean''--Nature, v. 344, p. 102, 1990.
New evidence for the essential role of the oceans in climate is
coming out of the recent World Ocean Circulation Experiment (WOCE),
supported by the National Science Foundation. A globe-spanning set of
ship-based observations in the '90s revealed that the depths of the
ocean had warmed significantly since previous observations in the '50s.
In fact, about half the ``missing'' greenhouse warming has been found
in the ocean. It was missing because models had projected a larger
increase than had been observed. It now appears this was because they
had not properly accounted for the capacity of the oceans to store
large quantities of heat on short timescales. In fact, it is easy to
calculate that if all of the extra heat due to the greenhouse change in
the radiation balance were to be deposited in the deep ocean, it would
take 240 years for it to rise 1+C. Thus, monitoring the ocean's
patterns of heat storage is absolutely essential for understanding
global warming, yet we have no system for such observations.
But the oceans do more than simply delay global warming. Research
over the past twenty years has brought a growing appreciation of how
the slow movement of warm and cold patches of ocean water can affect
our weather for months at a time. The alternating influence of El Nino
and la nina are now well known to the public and are rashly blamed for
any type of unusual weather. These 3-5 year period disruptions in
weather patterns are caused by the movement of warm water in the
tropical Pacific, and are now predictable up to a year in advance
because of a special monitoring network of ocean buoys maintained
there. The influence of El Nino on U.S. weather is well publicized, but
it actually explains only a small part of the variation in temperature
and rainfall over the United States. Some other natural ocean climate
cycles known as the Pacific Decadal Oscillation (PDO) and the North
Atlantic Oscillation (NAO) can explain much more of the variability in
winter-time weather than El Nino. (Figure 1.). The NAO in particular
has much more impact on the eastern half of the United States than El
Nino.
Exciting new findings suggest that the ocean controls the timescale
of the NAO, thus holding out the hope that these weather patterns will
be predictable when sufficient ocean observations become available.
Figure 1. The correlation of U.S. winter-time climate with El Nino, PDO
and NAO over a 35 year period. If we could predict these phenomena in
advance, then the square of the numbers represented by the colors gives
the winter climate variability that is potentially predictable. That
is, white areas would have no predictability, but in the brown areas
36% or more of winter climate changes could be predicted. However, we
do not yet have predictive capabilities for PDO or NAO. If predictions
are to be made we will require a greatly expanded ocean observing
system.
Recent research indicates that the NAO's changes in atmospheric
pressure patterns over the Atlantic are linked to the slow variation in
water temperatures, as the ocean currents rearrange the warm and cold
ocean patterns that serve to guide the atmosphere in its preferred
modes of oscillation. Only the ocean has the long-term memory to
provide the decadal time scales observed in the NAO. An understanding
of these natural modes of climate variation is essential for accurate
predictions of the regional trends in U.S. climate. That the two models
examined in the Climate Assessment report should differ so widely in
prediction of future U.S. precipitation is no surprise. Models are only
a repository for what we think we know, and an understanding of the
important oceanic phenomena such as PDO and NAO has not yet been
achieved. In order to understand these phenomena we need to observe the
motion of the deep warm and cold patches that give the ocean its multi-
decadal memory, and we need to sustain those observations through a few
cycles of the oscillations. In contrast to the 1,200 records of U.S.
land temperature used to examine climate trends in the report, we have
only three sites with anything like a continuous deep record in all of
the North Atlantic! For these few sites with rather short records, an
observation once a month is often the best we have. This observation
system is woefully inadequate. It is obvious that the ocean is the
long-term memory of the Earth's climate system yet we persist in
ignoring it. Some think it sufficient to look at the surface of the
ocean with a satellite and try to model the interior. However,
satellites can tell us nothing about the deep interior temperatures
that influence winter-time climate.
Figure 2. The North Atlantic Oscillation (NAO). Its ``high index''
state is shown on the left, this corresponds to particularly high
atmospheric pressure over the Azores, an intense low over Iceland.
Ocean winds are stronger and winters milder in the eastern U.S. When
the NAO index is low, ocean winds are weaker and the U.S. winter more
severe. Changes in ocean temperature distributions are also observed.
The Water Cycle and Thermohaline circulation
Also, satellites can tell us nothing about the salt content of the
ocean, which reflects the workings of the water cycle. There is an
increasing attention to the importance of the water cycle in global
change; for most communities drought or flood are more pressing
challenges than a few degrees of warming. However, there has been
little recognition that most of the water cycle occurs over the oceans.
It would take a diversion of only 1% of the rainfall falling on the
Atlantic to double the discharge of the Mississippi River. Water
travels quickly through the atmosphere, spending only about 10 days on
a short ride from one spot to another. Water molecules spend thousands
of years on the slow return flow in the ocean. But the process of water
leaving the surface of the ocean, and thereby changing its salt content
and density, drives an interior flow many times larger than the flux of
water due to evaporation and precipitation alone. This ``thermohaline
circulation'' is a key element of the climate system, as it is
responsible for most of the ocean's heat transport from equator to
pole. When salty water gives up its heat to the atmosphere, it can
become dense enough to sink to the bottom of the ocean, thereby keeping
making room for more warm water to come north for cooling. The North
Atlantic is the saltiest ocean and the most active site for such ``deep
convection''. However, if it becomes too fresh from rainfall the
surface waters cannot sink and the flow of warm water stops.
Figure 3. The influence of salt content (salinity) on the process of
deep convection. Normally, winter cooling at the surface causes deep
vertical mixing which releases much heat to the atmosphere (left). When
fresher water lies at the surface because of rain fall or ice melt, the
deep convection is prevented and only a shallow surface layer provides
heat to the air above (right). Thus, salinity is now considered a key
variable for climate studies.
Records from ocean sediments of the fossils of marine life indicate
that this has happened many times in the past, with dramatic
consequences for climate over a large area. The most recent event was
about 12,000 years ago, when the freshwater from melting glaciers shut
down the thermohaline circulation in the North Atlantic. This had
dramatic consequences for the North Hemisphere, returning much of it to
glacial conditions for 1000 years. The data indicate that this happened
rapidly, in only a decade or two. Some models predict that such abrupt
climate change could happen again as the water cycle intensifies with
future global warming. However, such transitions in the thermohaline
circulation have been shown to depend on the rate of interior mixing in
the ocean, and we know that this is incorrectly treated in the present
generation of climate models.
Model Deficiencies
In fact, oceanographers have many complaints about how poorly
climate models simulate the ocean. Because of computer limitations,
they must treat it as a very viscous fluid, more like lava or concrete
than water. Such models fail to simulate the real ocean's changes in
deep temperatures. We know that the ``sub-grid-scale''
parameterizations for mixing processes are incorrect, reflecting none
of the observed spatial variations or differences between heat and
salt. This mixing drives the interior flows in the ocean. We know that
the processes by which ocean currents give up their momentum are
incorrectly treated. And these are not problems that will quickly yield
to increased spatial and temporal resolution in the computer models.
Even if computer power continues to increase by an order of magnitude
every 6 years, it will be over 160 years \1\ before models have the
resolution necessary to simulate the smallest ocean mixing processes!
Society cannot afford to wait that long. We will not come to an
understanding of climate by more computational cycles of models with
incorrect physics. We require a systematic study of the sub-grid-scale
processes in the ocean. This is noticeably lacking in our current
Global Change Research Program.
---------------------------------------------------------------------------
\1\ It will take a factor of 10\8\ improvement in 2 horizontal
dimensions (100 km to 1 mm, the salt dissipation scale), a factor of
10\6\ in the vertical dimension (~10 levels to 10\7\) and ~10\5\ in
time (fraction of a day to fraction of a second); an overall need for
an increase in computational power of ~10\27\. With an order of
magnitude increase in computer speed every 6 years, it will take 162
years to get adequate resolution in computer models of the ocean.
Figure 4. The operation of a profiling float for the ARGO program.
These autonomous probes can provide unprecedented amounts of data from
the interior ocean at a modest cost. Knowledge of the interior ocean
temperature is necessary because these waters interact with the
---------------------------------------------------------------------------
atmosphere every winter through the process of deep convection.
Observing Deficiencies
While we have in place a system for monitoring El Nino, we have no
such ability to observe the motions of thermal anomalies in the mid-
and high-latitude oceans. Nor do we monitor the salt content of ocean
currents, to determine the potential for deep convection or to help
understand the vast water cycle over the oceans. But new technology,
the vertically profiling ARGO float (Figure 4.), promises to give us
the data we need to begin to understand this largest component of the
global water cycle. These are like weather balloons for the ocean,
drifting at depth for 10 days then rising to the surface to report
profiles of temperature and salinity to a satellite. They then
resubmerge for another 10 day drift, a cycle to be repeated 150 times
or more. The distance traveled between surfacings provides a measure of
the currents at the depth of the drift. The ARGO program (http://
www.argo.ucsd.edu/) is an international plan to maintain a global
distribution of ~3000 floats as a core element of a Global Ocean
Observing System (Figure 5.). Other parts of the system involve fixed
sites with moored buoys and underwater profilers that record
temperature and salinity all the way to the bottom of the ocean. These
new technologies will give us the data we need to begin to decipher the
complex climate phenomena we know to be operating in the ocean. Science
is the process of testing ideas against observations, and failure to
make the observations is an abandonment of the scientific process.
Figure 5. The surface salinity of the global ocean is represented by
the colors, with red being the saltiest and blue/purple the freshest.
3000 random dots, representing possible ARGO float positions, are seen
to provide good sampling of the large-scale patterns of salinity
variation. The Atlantic Ocean is seen to be saltiest, which helps
explain why deep convection is especially likely there, and its
important role in the thermohaline circulation.
What Can Congress Do?
1. Support fundamental research into the processes that govern the
ocean's role in climate. This includes the basic oceanic research
programs at NSF and ONR, and international programs like CLIVAR.
2. Make a substantial and long-term commitment to the creation of
a Global Ocean Observing System. Fund the ARGO program at NOAA (Ocean
Observations component of Climate Observations and Services) and the
ocean observing satellites of NASA.
Summary:
Policy makers would like climate scientists to produce firm
predictions. However, they must always remember that science is the
process of testing ideas against facts and access to quantitative data
is essential to the process. The ocean is a crucial element of the
climate system, yet its ``subgrid-scale'' processes are too poorly
understood and its basic structure too poorly monitored, to provide
much confidence in the details of present day predictions. The National
Climate Assessment Report is a good faith effort to assess the effects
of global warming on U.S. climate; the regional disagreements of the
two available models are to be expected, given our poor understanding
of the ocean. Global warming due to the effect of greenhouse gases on
the radiation balance is as certain as the law of gravity, but the
issues of how rapidly heat is sequestered in the oceans, its impact on
the water cycle, and the important regional variations in climate,
remain very challenging research questions.
Climate prediction is a hard problem, but appears to be tractable.
An abundance of evidence indicates that the key to long-term prediction
is in the workings of the ocean, which has 99.9% of the heat capacity
of Earth's fluids. It is the heart of the climate ``beast,'' the
atmosphere its rapidly waving tail, with only 0.1% of the heat
capacity. Let us get to the heart of the matter, with an unprecedented
new look at the ocean. We have the technical capabilities. The cost is
modest. The payoff is large. The society that understands long-term
climate variations will realize tremendous economic benefits with
improved predictions of energy demand, water resources and natural
hazards, and it will make wiser decisions on issues affecting the
habitability of the planet, such as greenhouse gas abatement.
The Chairman. Thank you very much. Dr. Singer.
STATEMENT OF DR. S. FRED SINGER, PROFESSOR EMERITUS OF
ENVIRONMENTAL SCIENCES, UNIVERSITY OF VIRGINIA, AND FORMER
DIRECTOR OF U.S. WEATHER SATELLITE SERVICE
Dr. Singer. Mr. Chairman, I have researched and published
mainly in atmospheric and space physics over the last years.
I am professor emeritus of environmental sciences at the
University of Virginia, and president of the Science and
Environmental Policy Project, which is a nonprofit, nonpartisan
research group of scientists. We all work pro bono, without
salary, and we do not solicit money from industry or
government, so we are fairly independent. We speak our minds on
many issues as we see fit. We are mainly interested in making
sure that the science underlying the various policies,
environmental policies is correct and sound.
The reason I have a skeptical view on the climate science
underlying the assessment is because it does not fit with the
evidence. My testimony concerns just three pieces of evidence,
which I will briefly outline.
The first statement I make is that there is no appreciable
climate warming today. I repeat, there is no appreciable
climate warming. This puts me at odds with many of my
colleagues, I realize that, including my distinguished
colleague, Tom Karl, but I hope that I can convince him and
others that the evidence supports what I have to say.
I think the evidence that the climate has not warmed in the
last 2 decades is overwhelming. I have four pieces of evidence.
The weather satellites, with which I am very familiar, do not
show any appreciable warming of the atmosphere in the last 20
years. In fact, if you take out 1998, the El Nino year, there
is even a slight cooling of the atmosphere in the last 20
years.
There has been long debate about this, but fortunately the
National Research Council of the National Academy of Sciences
has published a report this year in which they essentially
endorse the satellite data, and the fact that the atmosphere
has not warmed in the last 20 years.
Weather balloons carrying radios get exactly the same
result, and these are independent measurements of the
atmosphere. They also show no appreciable warming in the last
20 years.
The third piece of evidence is the temperature record for
the United States as produced by NOAA and also published by
NASA. The temperature record for the United States shows that
the temperature has not warmed appreciably since about 1940.
Now, the thermometers do show a global warming. It means
that there must be warming going on somewhere outside of the
United States, and outside of Western Europe, because neither
one of those two networks shows any appreciable warming.
This is very puzzling, and it is possible that the
thermometers are not giving correct readings, or that they are
contaminated in some way. The warming seems to occur mainly in
Northwestern Siberia and in subpolar regions of Alaska and
Canada. But when one checks proxy data, like tree rings, ice
cores, and things of that sort, which also are a way of
measuring temperature, they show no warming since 1940, so the
thermometer data that do show a warming are the odd man out,
and we need to do the necessary research to find out why that
is.
As of now, I would say that there is no appreciable warming
in the last 20 years and, by the way, if there is no warming in
the last 20 years, this means that this is not the warmest
century in the last 1,000 years. In fact, we believe it was
warmer 1,000 years ago than it is today. And this is not the
warmest decade in the last 1,000 years, either.
So you see, we have a chance here to have a good debate on
these issues, but this is probably more appropriate for the
American Meteorological Society meetings that we are going to
be attending soon.
My second point relates to the regional changes in
temperature, precipitation, and soil moisture. After all, this
is the important thing, because all of the impacts of climate
change are based on what is actually happening in the region.
My belief is, and I believe everyone would agree, that to
predict regional changes is beyond the state-of-the-art of
climate models.
Climate models cannot even predict properly the global
changes, but to predict regional changes is practically
impossible, and we have proof of that. The proof is actually in
the report itself, the report that Dr. Janetos has just
referred to. The two climate models that are used in the report
give opposite results in 9 of the 18 regions that have been
studied.
For example, when it comes to rainfall the report shows the
Dakotas losing 85 percent of their current rainfall in one
model, while the second model shows a gain of 75 percent. These
opposite results occur in 9 cases out of 18, and in some other
cases the results show a huge difference.
The same is also true with soil moisture. The Canadian
model that was used predicts a drier Eastern United States. The
British model that was used predicts a wetter Eastern United
States.
So we conclude that the model results are not credible, and
therefore we believe that the conclusions that are drawn about
the impact of these climate changes are interesting exercises
but should not be taken too seriously.
My third point: I want to discuss sea level rise. Sea level
rise is widely feared, but also very much misunderstood. Most
people think the sea level rose in the last century because
temperatures rose in the last century. That is not so. Sea
level has been rising for about 15,000 years. Sea level rose by
400 feet in the last 15,000, and the reason it rose is because
the ice melted at the end of the last Ice Age.
First, the ice melted in North America and Northern Europe,
and that caused a very rapid rise in sea level. We can actually
measure it. It is about 80 inches per century, as measured.
Once that ice was gone, the melting slowed down. But the
melting still continues, though, in the Antarctic, but now it
is the West Antarctic ice sheet that is melting slowly, and has
been melting for 15,000 years, and this slow melting of the
West Antarctic ice sheet amounts to about 7 inches per century
of sea level rise.
This is the sea level rise that is going on right now. This
will continue for another 6,000 years, unless another Ice Age
intervenes. But assuming that we do not get another Ice Age, we
will have sea level rise going on for another 6,000 years no
matter what we do.
We cannot affect this in any way. We cannot stop the tides,
we cannot stop continental drift, we cannot stop the Antarctic
ice sheet from melting. It is just going to continue its slow-
melting process. It has to do with the fact that it is warmer
now than it was 15,000 years ago.
Finally: The bottom line of all of this is that the
scientific evidence does not support the results of the
National Assessment. It also tells us that we should be doing
serious research on both atmospheric and oceanic processes, and
that this research needs to be carried out much further before
we can have confidence in any assessment report.
My conclusion: The National Assessment should definitely
not be used to justify any irrational or unscientific energy
and environmental policies, and that advice I think is
particularly relevant to the forthcoming Presidential debates
and campaigns.
Thank you very much.
[The prepared statement of Dr. Singer follows:]
Prepared Statement of Dr. S. Fred Singer, Professor Emeritus of
Environmental Sciences, University of Virginia, and Former Director of
U.S. Weather Satellite Service
Mr. Chairman, Ladies and Gentlemen,
My name is Fred Singer. I am Professor Emeritus of Environmental
Sciences at the University of Virginia and the founder and president of
The Science & Environmental Policy Project (SEPP) in Fairfax, Virginia,
a non-partisan, non-profit research group of independent scientists. We
work without salaries and are not beholden to anyone or any
organization. SEPP does not solicit support from either government or
industry but relies on contributions from individuals and foundations.
We hold a skeptical view on the climate science that forms the
basis of the National Assessment because we see no evidence to back its
findings; climate model exercises are NOT evidence. Vice President Al
Gore keeps referring to scientific skeptics as a ``tiny minority
outside the mainstream.'' This position is hard to maintain when more
than 17,000 scientists have signed the Oregon Petition against the
Kyoto Protocol because they see ``no compelling evidence that humans
are causing discernible climate change.''
Others try to discredit scientific skeptics by lumping them
together with fringe political groups. Such ad hominem attacks are
deplorable and have no place in a scientific debate. To counter such
misrepresentations, I list here qualifications relevant to today's
hearing.
Relevant Background
I hold a degree in engineering from Ohio State and a Ph.D. in
physics from Princeton University. For more than 40 years I have
researched and published in atmospheric and space physics. I received a
Special Commendation from President Eisenhower for the early design of
satellites. In 1962, I established the U.S. Weather Satellite Service,
served as its first director, and received a Gold Medal award from the
Department of Commerce for this contribution.
Early in my career, I devised instruments to measure atmospheric
parameters from satellites. In 1971, I proposed that human production
of the greenhouse gas methane, through cattle raising and rice growing,
could affect the climate system. This was also the first publication to
discuss an anthropogenic influence on stratospheric ozone. In the late
1980s, I served as Chief Scientist of the Department of Transportation
and also provided expert advice to the White House on climate issues.
Today, by presenting evidence from published peer-reviewed work, I
will try to rectify some erroneous claims advanced at the May 17 NACC
hearing.
1. There Is No Appreciable Climate Warming
Contrary to the conventional wisdom and the predictions of computer
models, the Earth's climate has not warmed appreciably in the past two
decades, and probably not since about 1940. The evidence is abundant.
a) Satellite data show no appreciable warming of the global
atmosphere since 1979. In fact, if one ignores the unusual El Nino year
of 1998, one sees a cooling trend.
b) Radiosonde data from balloons released regularly around the
world confirm the satellite data in every respect. This fact has been
confirmed in a recent report of the National Research Council/National
Academy of Sciences.\1\
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\1\ National Research Council. ``Reconciling Temperature Trends.''
National Academy Press, Washington, DC. January 2000.
---------------------------------------------------------------------------
c) The well-controlled and reliable thermometer record of surface
temperatures for the continental United States shows no appreciable
warming since about 1940. The same is true for Western Europe. These
results are in sharp contrast to the GLOBAL instrumental surface
record, which shows substantial warming, mainly in NW Siberia and
subpolar Alaska and Canada.
d) But tree-ring records for Siberia and Alaska and published ice-
core records that I have examined show NO warming since 1940. In fact,
many show a cooling trend.
Conclusion: The post-1980 global warming trend from surface
thermometers is not credible. The absence of such warming would do away
with the widely touted ``hockey stick'' graph (with its ``unusual''
temperature rise in the past 100 years); it was shown here on May 17 as
purported proof that the 20th century is the warmest in 1000 years.
2. Regional Changes in Temperature, Precipitation, and Soil Moisture?
The absence of a current global warming trend should serve to
discredit any predictions from current climate models, including the
extreme warming from the two models (Canadian and British) selected for
the NACC.
Furthermore, the two NACC models give conflicting predictions, most
often for precipitation and soil moisture.2,3 For example,
the Dakotas lose 85% of their current average rainfall by 2100 in one
model, while the other shows a 75% gain. Half of the 18 regions studied
show such opposite results; several others show huge differences.
---------------------------------------------------------------------------
\2\ R. Kerr. ``Dueling Models: Future U.S. Climate Uncertain.''
Science 288, 2113, 2000.
\3\ P.H. Stone. ``Forecast Cloudy: The Limits of Global Climate
Models.'' Technology Review (MIT), Feb/March 1992. pp. 32-40.
---------------------------------------------------------------------------
The soil moisture predictions also differ. The Canadian model shows
a drier Eastern U.S. in summer, the UK Hadley model a wetter one.
Conclusion: We must conclude that regional forecasts from climate
models are even less reliable than those for the global average. Since
the NACC scenarios are based on such forecasts, the NACC projections
are not credible.
3. Sea Level Rise: Controlled by Nature not Humans
The most widely feared and also most misunderstood consequence of a
hypothetical greenhouse warming is an accelerated rise in sea levels.
But several facts contradict this conventional view:
a) Global average sea level has risen about 400 feet (120 meters)
in the past 15,000 years, as a result of the end of the Ice Age. The
initial rapid rise of about 200 cm (80 inches) per century gradually
changed to a slower rise of 15-20 cm (6-8 in)/cy about 7500 years ago,
once the large ice masses covering North America and North Europe had
melted away. But the slow melting of the West Antarctic Ice Sheet
continued and will continue, barring another ice age, until it has
melted away in about 6000 years.
b) This means that the world is stuck with a sea level rise of
about 18 cm (7 in)/yr, just what was observed during the past century.
And there is nothing we can do about it, any more than we can stop the
ocean tides.
c) Careful analysis shows that the warming of the early 1900s
actually slowed this ongoing SL rise,\4\ likely because of increased
ice accumulation in the Antarctic.
---------------------------------------------------------------------------
\4\ S.F. Singer. Hot Talk, Cold Science: Global Warming's
Unfinished Debate. (The Independent Institute, Oakland, CA. (second
edition, p. 18)).
---------------------------------------------------------------------------
The bottom line: Currently available scientific evidence does not
support any of the results of the NACC, which should therefore be
viewed merely as a ``what if'' exercise, similar to the one conducted
by the Office of Technology Assessment in 1993.\5\ Such exercises
deserve only a modest amount of effort and money; one should not
shortchange the serious research required for atmospheric and ocean
observations, and for developing better climate models.
---------------------------------------------------------------------------
\5\ Office of Technology Assessment. ``Preparing for an Uncertain
Climate.'' Govt. Printing Office, Washington, DC. 1993.
---------------------------------------------------------------------------
The NACC should definitely NOT be used to justify irrational and
unscientific energy and environmental policies, including the
economically damaging Kyoto Protocol. These policy recommendations are
especially appropriate during the coming presidential campaigns and
debates. I respectfully request that an expanded exposition \6\ be made
part of my written record. [The Executive Summary is in the appendix,
the whole document can be found at: //www hoover.stanford.edu/
publications/epp/102/102complete.pdf ]
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\6\ S.F. Singer. ``Climate Policy--From Rio to Kyoto: A Political
Issue for 2000--and Beyond.'' Hoover Institution Essay in Public Policy
No. 102. Stanford, CA, 2000.
The Chairman. Thank you, Dr. Singer. In other words, you
reject the findings of the Assessment practically in its
entirety.
Dr. Singer. I think these are interesting exercises, what-
if exercises, but I do not think they should be taken
seriously.
The Chairman. Dr. Schmitt, in the climate change you have
noted in your findings, what is the impact on the ecology of
the oceans, such as the effect on reef life, et cetera?
Dr. Schmitt. Well, I am hardly an expert, but there are
very significant impacts on fisheries. I know the cod fishery
in New England has changed a lot. It is difficult to sort out
whether it is due to overfishing or just changes in the North
Atlantic Oscillation, because the water off Labrador is so much
colder now than it was 10, 15 years ago.
In other areas warming in tropical areas has a great impact
on the life of corals. There is a phenomenon called coral
bleaching, which basically kills a coral reef, and I believe
that occurs if the water gets too warm. In other areas the
stocks of salmon have been correlated with these climate
phenomenon such as the North Atlantic Oscillation and the
Pacific Decadal Oscillation.
These phenomena, with their long time scales--they are 5,
10, 15 year cycles--hold out the hope of predictability because
the ocean has this long memory of the heat content. It has
enormous heat content. It has 99.9 percent of the heat content
of the climate system, and we need to be doing a much better
job on monitoring that heat content.
The Chairman. Mr. Karl, do you have a response to Dr.
Singer's views?
Mr. Karl. Yes. I have--I do not know where to begin, to be
quite honest.
Dr. Singer. Just start anywhere.
Mr. Karl. I guess I would first point out that what we did
in the assessment was draw on the published referenced
literature. In fact, I think if you look at the references in
the assessment there is--probably over 95 percent are from
papers that have been peer-reviewed. The other 5 percent are
reports that often were used because we needed to obtain the
data from those reports.
What I would just want to point out is that the position of
Dr. Singer, although I very much respect his opinions, is quite
at odds with the scientific published literature. I would just
point out a few egregious examples of what I have heard.
50 percent of the rise, or more than half of the rise in
sea level is due to the expansion of ocean waters. As
temperatures increase, the ocean density increases, and it has
nothing to do with the melting of ice glaciers.
The other aspects that I heard which I would completely
disagree with, and that is the warming in the U.S. record. It
is very clear, in fact, especially in the last decade or two,
the U.S. was lagging behind global temperature increases up
till the early 1980's, and since the mid-1980's, and
particularly during the 1990's, the U.S. has virtually captured
the rest of the globe.
That is not to be unexpected. In fact, if you look at one
area in the country, the Southeast part of the U.S., it is
where we have not seen much of an increase in temperature. In
fact, there have been very small changes in temperature, but
again if you look at the 1990's in the Southeast, we are almost
now as warm as we were back in the 1930's.
And again, I might point out that in the Arctic we have had
record low ice extents in the Arctic. In fact, if you look at
the latest IPCC report that is up for review, it is documented
that we also see reduced snow cover extending across the
northern hemisphere.
So it is not just the temperature records that we use to
deduce the fact that the globe is warming. There are many, many
other ancillary pieces of information that are used as well.
So those are just a few of the things I would like to point
out.
The Chairman. Dr. Janetos, can you comment on the Science
Magazine article which claims that the two models used in the
report, the Hadley Center and the Canadian, are not intended,
or capable of predicting future impacts of climate change on a
regional basis?
Dr. Janetos. Mr. Chairman, in the assessment we tried to be
very careful to say what we have not done is try to predict
exactly what the future will be like. Each of these models,
each of these general circulation models was selected after a
careful review of the criteria that we set a priori in order to
understand the potential consequences.
They had to have saved the right data, they had to have
used an emissions scenario that was already well understood,
and they had to be documented in the scientific review
literature.
What we have tried to do is essentially ask the question,
what if the models are correct? Since we cannot distinguish
between them on scientific bases, we need to be able to
understand the implications of the different plausible futures
that they hold for the U.S.
The Chairman. Thank you. We will be submitting written
questions that we hope you will be able to respond to. I
apologize for the short-circuiting of this hearing. We will be
asking the second panel to come back. We thank you for taking
your time to come before the Committee.
You have added a lot to this very important discussion, and
I want everyone to be very aware that we will continue to
pursue this with further hearings. I think that it is an issue
that is extremely important for us to seriously consider, and I
thank you for being here. I thank you for your continued
efforts, and I hope I have the opportunity to personally visit
with all the members of the panel as we explore this very
complex and difficult situation. I thank you.
Unfortunately, this hearing is adjourned.
[Whereupon, at 10:10 a.m., the Committee adjourned.]
A P P E N D I X
Response to Written Questions Submitted by Hon. John McCain
to Thomas R. Karl
Question 1. Can you explain the process used in the report to address
the differences between the results of the two computer models and how
this process is used to identify new research areas?
Answer. A lexicon was developed to communicate scientific
uncertainty related to the scenarios from the two climate models used
in the National Assessment as well as other models, data, information,
and state of knowledge. This lexicon conveyed areas of uncertainty by
linking words with probabilities. For example, if the National
Assessment Synthesis Team (NAST) assessed the about even odds for an
event the word `possible' was used. On the other hand, if the NAST was
fairly certain about an event, then words like ``very likely'' or
``very probable'' were used to indicate that there was more than 90%
chance of occurrence. Where both models agreed, projections were seen
as more certain. In cases where model results differed, both possible
future scenarios were examined and results were characterized as less
certain. Model results were not merged.
Whenever the NAST encountered instances where there was
considerable uncertainty about the outcome these areas were then
identified in a `Research Needs' section of the report. In our Research
Needs section we recommend a number of measures that are required to
improve our confidence in modeling future climates.
Question 2. If the report explicitly does not ``merge'' the results of
models that disagree, can this assessment be considered a fair analysis
of climate change? Furthermore, when the two models diverged, where
these results downplayed in the report versus when they concurred?
Answer. In response to the first question, it is difficult to
understand why the assessment would not be considered fair if the two
primary models were not merged. As indicated above, the NAST did not
merge the scenarios from the models, but rather the NAST reflected the
uncertainty related to several different possible outcomes and
expressed this lack of confidence through use of the lexicon.
In response to the second question, the answer is no. Again, the
NAST painstakingly used the lexicon to express its confidence in any
projected changes for the 21st Century. Projected scenarios from all
relevant models were discussed. This included both of the two primary
models as well as the secondary models used in the Assessment.
Question 3. Dr. Schmitt has raised several issues concerning the impact
of the oceans on the climate modeling results. How sensitive are the
climate change impacts on the U.S. to changes within the ocean water
temperatures?
Answer. Dr. Schmitt's remarks refers to improving climate forecasts
from climate models that are dependent upon initial conditions. These
deterministic climate model forecasts require information about the
current state of the oceans. Clearly, it is very important to have
comprehensive high-quality real-time ocean observations available to
properly initialize these models.
The Global Climate Models used in the National Assessment do not
require real-time initial conditions. They are self-contained models
and generate their own ocean climate. Changes in ocean temperatures can
have a large impact on the climate of the U.S. An obvious example
relates to the changes of ocean temperatures in the tropical Pacific
related to the El Nino southern oscillation and its effect on the
temperature and precipitation in the U.S. Another example relates to
hurricane formation. Water temperatures significantly less than 80
degrees Fahrenheit do not provide enough energy to the atmosphere to
spawn powerful hurricanes. And as a result, hurricane formation is
highly seasonal dependent.
Question 4. In the past few years, the U.S. experienced some
distinctive weather patterns, namely El Nino and la nina. Can you
discuss how these and other warm ocean water related weather patterns
factors into your modeling efforts?
Answer. First, it is important to understand that El Nino and la
nina are the opposite phases of an oscillation that is atmospheric and
oceanic based. As such, la nina reflects cold ocean waters in the
tropical Pacific while El Nino reflects the opposite conditions, warm
waters. Present-day Global Circulation Models are only now beginning to
show success in simulating important ocean-atmosphere oscillations such
as the El Nino/Southern Oscillation. Neither of the models used in the
National Assessment has a fully satisfactory representation of the El
Nino/la nina oscillation, and it is likely that this has lead to some
of the differences between model projections. The Global Climate Model
that has been most successful in reproducing the El Nino/la nina
events, primarily because of its higher resolution, is the Max Planck
Model from Germany. Unfortunately, based on the NAST's selection
criteria, we could not use this model as a primary model, but the NAST
was able to point out that this model projects a major increase in the
intensity of both El Nino and la nina events as the globe warms. This
could be very important, and in our Research Needs section of the
National Assessment the NAST points out the importance of more research
related to climate model inter-comparisons, representation of important
ocean processes, and analysis of possible influence of climate change
on existing patterns of climate variability.
Question 5. Do you anticipate that any of the ongoing university
regional studies will contradict the findings of the current draft
report?
Answer. I do not anticipate that the any of the ongoing studies
will contradict the current National Assessment Draft Report, but I
would be surprised if they did not add additional insight into
important issues and uncertainties. In assessing such a broad range of
science, economics, and sociology, it was very clear to us that new
understanding and insights were occurring continuously. Most often
however, these insights made incremental additions to our
understanding. A good example of this are the incremental advances in
our understanding about global change as reflected in the series of
Inter-governmental Panel on Climate Change Assessments completed during
the 1990s. It is rare in science, that a discovery or theory completely
displaces the old paradigm. We acknowledge that such things can occur
however, such as the discovery of the ``Ozone Hole'' or Einstein's
Theory of Relativity.
______
Response to Written Questions Submitted by Hon. John McCain to
Dr. Anthony C. Janetos
Question 1. Some critics of this report charge that the Administration
has ignored scientific and analytical procedures, and instead produced
an advocacy-driven document. Given that most scientific studies are not
open to the public, do you believe that ``value'' was added to the
process by involving the public in this manner?
Answer. The public has been involved in two ways throughout the
assessment process. First, during the workshop phase of the process, in
which more than twenty workshops were held around the country, broad
public participation was sought. The role of the workshop participants
was primarily to identify environmental issues of concern to people in
the different regions of the U.S. This input was then used to help
decide which issues of importance within each region would be followed
up in scientific studies.
The second way in which the public was involved was opening the
Synthesis reports up to a public comment period, at the specific
request of the Congress. We received many comments from people who
otherwise might not have had the opportunity to read such a report at
this stage in its development. Some of these comments have been quite
insightful and helped us improve the document as a method of
communication with a broad readership.
It is correct that most national scientific processes have not been
so open to soliciting input from the public. I argue that our process
has been enhanced by the public participation that we received, without
resulting in an advocacy-driven document. We have focused on issues
that people perceived to be important to them, and not just on issues
of interest to the scientific community. At the same time, we were able
to bring up-to-date scientific knowledge and methods to bear on the
issues that had been identified. Objective scientific and analytical
procedures and methods have been used throughout. Our objectivity has
been ensured by extensive peer review.
Would you also discuss the level of participation from the private
sector?
Answer. The private sector has been involved in several different
ways. Our oversight panel is broadly representative of several
different sectors, including academia, the for-profit private sector,
and non-governmental organizations (NGO's). The National Assessment
Synthesis Team and other contributors to the national reports include
individuals from all these sectors as well, plus experts from
government research laboratories. Many individuals in the private
sector have reviewed all or part of the reports, and have offered their
comments to us. Finally, many of the regional workshops included
participants from the private sector, who were important contributors
to the process of identifying issues for scientific analysis.
Question 2. Can you describe the peer review process that the
assessment team incorporated into its findings?
Answer. The peer review process had several steps. First was a
round of technical peer review on the initial drafts of the national
reports, which began in November of 1999, and continued into January of
this year. We received more than 300 comments from individuals who
identified themselves as technical experts in the many different
aspects of the report. This technical peer review included experts in
the government agencies, as well as academia, the private sector, and
NGO's. The second step was submitting the entire report to a list of
about 20 experts identified by our oversight panel, who were charged
with evaluating the entire structure of the report, its responsiveness
to its original intent, and the strength of the findings and
conclusions. Throughout, we have had the benefit of comments from our
oversight panel.
The National Assessment Synthesis Team has considered every written
comment that it has received. We have responded to comments in writing,
documenting either how the comment has been taken into account, or why
we have decided not to do so. These responses to comments have also
been shared with our oversight panel.
Question 3. How did your ``bottom up'' approach to the assessment
report impact the findings or scope of your work?
Answer. I believe that the approach of identifying issues through
involvement of the public in the series of workshops did affect the
scope of the work. Specifically, it enabled us to focus on the issues
viewed as most important by the participants of the workshops. However,
the analysis of those issues was done by experts, so that the actual
findings themselves are the result of objective analysis.
Question 4. Did the oversight panel for the National Assessment
Synthesis Team offer any cautious or contradictory statements
throughout the reporting process?
Answer. The oversight panel has been cautious throughout, and has
been especially helpful to us in ensuring that we have described
accurately the scientific basis for our findings, and been open about
the degree of uncertainty that remains. They have not provided
contradictory statements.
______
Response to Written Questions Submitted by Hon. John McCain
to Dr. Raymond W. Schmitt
Question 1. Your written statement mentions that the ocean is the long
term memory of the climate system. Would you discuss what methods are
available to retrieve that long-term memory?
Answer. Most of the heat energy reaching Earth is absorbed into the
upper ocean at low to middle latitudes. A significant fraction of this
is used to heat and moisten the atmosphere on a daily basis, causing
the winds and rain we experience as weather. But over the course of the
seasons, large amounts of heat are stored within the ocean during
spring and summer for release in the winter. This is the basic
moderating influence of the oceans on climate; the vast heat capacity
of the oceans prevents the winter from becoming too cold, and the
summer from becoming too hot, especially in areas near the coast. But
we have also found that ocean currents are capable of moving tremendous
quantities of heat around the planet. This has an essential role in the
climate system, fully half of the transport of heat from equator to
pole is accomplished by the slow-moving, high heat-capacity ocean, with
the other half of the heat transport carried by the fast-moving, low
heat-capacity atmosphere. The atmosphere cycles its water vapor and
heat within two weeks, so it has only a short-term memory of past
conditions. However, the ocean's heat-content is so large its memory
time is decades to centuries, when the deep ocean is considered.
The way to retrieve and interpret the long term climate memory of
the oceans is to measure the temperature at depth. Satellites provide
an estimate of the temperature of the ocean in a thin surface layer but
tell us nothing about the deep-reaching temperature signals necessary
to help predict the climate a season or even a decade ahead. New
technology of profiling floats (the ARGO program), new profiling
moorings that measure temperature and salinity and maintenance of
traditional ship-based observations will all help to acquire data on
the deep temperature and salinity of the ocean. We will never decipher
the mysteries of the climate system without measuring the dominant
portion of its heat content that resides in the ocean.
Question 2. Would you briefly discuss the importance of ocean salinity
(or salt content) to climate studies?
Answer. Salinity variations have nearly as much influence on
seawater density as temperature changes. This means that in the high
latitude ocean salinity plays a very important role in determining
whether the surface waters will be dense enough to sink and become deep
water. Salinity can be decreased there by rain fall, river runoff and
ice melt. If deep water ceases to form then the ``thermohaline''
circulation is disrupted and the warming influence of the North
Atlantic on American and European weather is much reduced. Increased
rainfall in high latitudes and subsequent collapse of the thermohaline
circulation is a prediction of global warming models, with dramatic
consequences for climate. However, the ocean models and measurements
are presently inadequate to say whether thermohaline collapse is
probable or even possible with global warming. In the tropics, high
rainfall rates can cause low salinity water to collect at the ocean
surface and modify the ocean's transfer of solar heat to the
atmosphere. Salinity variations in the ocean reflect the workings of
the greater part of the global water cycle; a mere 1% of the rainfall
on the Atlantic ocean would double the discharge of the Mississippi
River. Yet salinity is a very poorly monitored variable; for many areas
of the ocean, there has never been a salinity measurement. Thus, it is
very important that we begin to make much greater use of new technology
such as ARGO floats, moored and drifting buoys and ships to better
define the patterns of salinity variation in the ocean. Only then will
we achieve an adequate understanding of the global water cycle and its
variations which are so important to society.
Question 3. You mentioned that because of computer limitations, many
models must treat the ocean as a very viscous fluid, more like lava or
concrete than water. What are the implications of this assumption?
Answer. The models that are run for climate predictions cannot
resolve or represent the smaller scales of variability in the ocean.
This means that the many eddies and fronts we find in the real ocean
(100 km in size and smaller) are not in the models. This introduces a
number of defects in the models even for the large scales which are
well resolved. For instance, some currents are driven by eddies, and
without eddies such currents are not found in the models. Also, the
ocean's interior mixing processes are known to be caused by internal
waves, yet there are no internal waves in the models. Mixing controls
the patterns of the deep currents, which are notoriously wrong in the
models. The problem gets worse for climate projections of decades or
centuries, with many ocean phenomena missing or seriously
misrepresented. Without an accurate portrayal of ocean dynamics,
prediction of future climate states is fundamentally impossible.
Question 4. Your written testimony states that it is unlikely that we
will have the necessary computer power over the next 160 years, even
with an increased order of magnitude every 6 years, to simulate the
smallest ocean mixing processes. What are our alternatives to gain a
better understanding of these processes?
Answer. Study the real ocean. We can develop a better understanding
only through dedicated ``process'' studies focussed on these different
phenomena. This allows the development of ``parameterizations'' of the
small scale processes that can be used in the numerical models. The
United States had a significant research effort on small-scale ocean
processes during the cold war through support of the Office of Naval
Research, but funds from that source are now much diminished. There is
a great need for a revitalization of such work in order to bring the
ocean climate models toward some semblance of reality.
______
Response to Written Questions Submitted by Hon. John McCain
to Dr. S. Fred Singer
Question 1. The report states that by using the two selected computer
models, a plausible range of future actions are captured, with one
model being near the lower end and the other near the upper end of
projected temperature changes over the U.S. Do you agree with this
statement?
Answer. The National Assessment Report chose two climate models
(out of perhaps two dozen) to provide scenarios for the 21st century.
The selection criteria are not readily apparent. One model came from
the Canadian Climate Center; it predicts extreme temperature rises over
the U.S. (of 11+F by 2100). The other model chosen was produced by the
Hadley Center in Britain; it predicts less extreme temperatures.
The main point, however, is that BOTH models are already too high
and therefore proven wrong by the temperatures observed in recent
years. As shown in my testimony, there has been no appreciable warming
over the U.S. since about 1935, according to the analysis by Dr. James
Hansen of NASA-GISS. Notwithstanding the oral response by Tom Karl,
virtually the same is true for the analysis published by NOAA-NCDC.
To verify this, it is only necessary to view the disparity between
the observed temperatures (see my written testimony) and the calculated
temperatures (see written testimony of Karl/Melillo/Janetos).
Question 2. What are your thoughts as to why regional forecasts from
the climate models disagree so strongly in some areas and not as much
in others?
Answer. At the present state-of-the-art of climate models, regional
forecasts are even worse than those for global averages. No reliance
whatever should be placed on them. The strong disagreements between the
model predictions themselves provide adequate confirmation for my
statement.
Question 3. Your written statement mentions that a careful analysis
shows that the warming of the early 1990's actually slows ongoing sea
level rise. Can you explain this finding?
Answer. Sea levels have been rising for about 15,000 years, since
the peak of the last ice age. The total rise has been about 400 feet.
Sea levels are continuing to rise at a rate of about 7 inches per
century, and will continue at about that rate for several millennia
more as slow melting continues in the Antarctic.
As global temperatures fluctuate (no matter whether from natural
causes or possible human causes), the ongoing sea level rise may be
expected to show slight modulations; it may slow down for some decades
or it may accelerate. It all depends on whether a warming of the oceans
produces a greater or lesser effect than an accumulation of ice in the
Antarctic from increased ocean evaporation and subsequent
precipitation. (These two effects on sea level oppose and nearly cancel
each other.)
When we investigated what happened during the major warming between
1920 and 1940, we found empirically that the rise in sea level slowed
down. We therefore expect that any future warming, unless extreme and
sustained over many centuries, will likewise reduce the rate of sea
level rise rather than accelerate it. The existing fears about rising
seas from greenhouse warming have no scientific foundation whatsoever.
They are based on hype rather than observed facts.
Question 4. Do you accept the claim that the 20th century was the
warmest of the past 1000 years?
Answer. The claim that the present century is the warmest of the
past 1000 years relies on the ``hockey-stick'' temperature graph (Mann,
Bradley, and Hughes, Geophysical Research Letters 1999). It is derived
from various proxy data rather than thermometer records; yet it has
been widely cited. It forms the cornerstone of the claimed
``discernible human influence'' in the Summary for Policymakers of the
IPCC-Third Assessment Report.
The graph is actually a composite of two records: (i) temperatures
from ``proxy'' data (tree rings, etc.) going back to 1000AD; and (ii) a
superimposed global instrumental (thermometer) record of the past
century.
Close examination reveals that the proxy record stops in 1980 and
therefore does not independently support the post-1980 temperature
increase suggested by the thermometer data. Thus there is no evidence
for a substantial warming since 1980 (or even since 1940). There is no
evidence for the claim that the present century is the warmest of the
past 1000 years. And there is no evidence to back the claim of a
``discernible human influence'' on global climate.
______
Prepared Statement of Hon. Larry E. Craig, U.S. Senator from Idaho
Mr. Chairman, thank you for inviting me to testify at this very
important hearing. On June 16, 2000, I spoke on the Senate Floor about
the Administration's recently released draft National Assessment
Synthesis Report. I ask that a copy of that Statement be included in
the record of this hearing.*
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* The information referred to was not available at the time this
hearing went to press.
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Mr. Chairman, the potential of global climate change is one of the
most important environmental issues of this new century. The stakes are
high. Worst-case scenarios involving rising temperatures and sea levels
scare many people. On the other hand, premature government action to
cut back energy use to levels lower than those in the growth-oriented
nineties could cool the economy faster than it cools the climate.
What is required at this time, Mr. Chairman, is steady and
thoughtful leadership. Responsible government includes environmental
stewardship. However, the ultimate obligation of government is to
protect freedom. By freedom I mean the opportunity to achieve one's
true potential as an individual, a community, or a nation: the freedom
to grow!
Freedom spawns discovery and innovation. Discovery and innovation
solve problems and create opportunities. This is the true spirit of
America.
Mr. Chairman, today you will have the co-chairs of the National
Assessment before you. These are accomplished men with impressive
scientific backgrounds. The Committee will have the opportunity to
question them on a document that I believe is long on fear and short on
conclusive science.
Let me lay-out some of the reasons why I am so concerned about this
document.
The National Assessment process was authorized under the Global
Change Research Act of 1990 but did not officially begin until January,
1998--one month after the Kyoto Protocol. The final report was expected
in January, 2000, but was delayed.
Last year, in the Fiscal Year 2000 appropriations, Congress
directed that all research used in the National Assessment must be
subjected to peer review and made available to the public prior to use
in the Assessment, and the Assessment must be made available to the
public through the Federal Register for a 60 day public comment period.
This was not challenged by the Administration.
The Administration released a ``draft'' summary report on June 12th
of this year by posting it on a website and publishing a notice in the
Federal Register that it was available for comment until August 11th.
This action is clearly at odds with Congressional intent. The
underlying regional (geographic) and sector (health, agriculture,
forests, water, coastal) work that was to have served as the basis for
the summary report has not been completed or made available for review.
In a June 30th letter to Congressman James Sensenbrenner, Chairman
of the House Committee on Science, Neal Lane, who testified before this
Committee on May 17th Mr. Chairman, stretched credibility in defending
this action. Although taxpayer funds were provided to support the work,
he claimed the underlying reports were not ``federal'' reports and
therefore not covered by the earlier Congressional guidance. The
underlying reports are to be completed over the next year or so and
published by the respective teams working on them.
Mr. Chairman, a question that begs an answer is: Why the rush to
release the National Assessment? The premature release of this document
allows for more polarizing advocacy. Although supposedly a ``draft''
report published for technical review and comment, it was trumpeted by
President Clinton on the day of its release and served as a basis for
repeating tired claims:
``It suggests that changes in climate could mean more extreme
weather, more floods, more droughts, disrupted water supplies, loss of
species, dangerously rising sea levels.''
It's easy to miss (or ignore) the qualifications to these
predictions and simply report that the Assessment forecasts dire
changes in climate in the future. For example, a page one story in The
New York Times on June 12th carried the headline: ``Report Forecasts
Warming's Effects--Significant Climate Changes Predicted for the
Country.''
In Texas, a July 4th story by the environmental reporter at the
Dallas Morning News reported on action by five environmental groups
asking Governor Bush--``to launch a Texas assault on global warming,
which scientists say could heat up North Texas in the next century.''
The story went on to discuss the draft National Assessment including
the comment--``Two computer simulations of the future of Texas climate
show sharp rises in the July heat index, with the worst impact in North
Texas.''
Not everyone has been misled. The Wall Street Journal published an
article entitled: ``U.S. Study on Global Warming May Overplay Dire
Side'' on May 26th, in anticipation of the impending release. A similar
story ran in The Detroit News on May 28th. Numerous Op-eds and Letters
to the Editor have also run.
However, Mr. Chairman, the early release of this document raises
more intriguing political questions than helpful probative scientific
ones. For example, it puts the Assessment on a timetable for inclusion
in the UN's Intergovernmental Panel on Climate Change's ``Third
Assessment Report'' on climate change which is due to be finalized next
year. In fact, Mr. Chairman, I have been informed by staff that drafts
are already circulating for comment and these drafts include references
to the U.S. National Assessment.
It is becoming clear that the June 12th release of the Assessment
is serving as support for campaign claims by Al Gore to support his
views on climate and energy use. Indeed, his release on environment and
energy policy occurred just two weeks later on June 26th.
Mr. Chairman, the Administration could have avoided seeding these
concerns if it had followed the common sense approach requested by
Congress and taken the time to get it right:
First, complete the underlying regional and sector work, peer
review the science used as its basis, and make the results available
for public comment;
Second, write the synthesis overview report based on this work, not
independently, peer review the results and make a complete draft easily
available for all interested citizens to review with enough time to
gather complete comments and expose them to the public.
In addition, Mr. Chairman, the independent National Research
Council should have a strong role in the drafting process, not just
White House allies as implied in some critiques.
Lastly, but importantly, one must question the use of foreign
computer models in this study. Was this in our best interest? The
National Assessment used a Canadian and a British Large Scale General
Circulation Model (GCM's) to make climate change predictions at a
regional level. According to a June 23rd Science Magazine article
entitled ``Dueling Models: Future U.S. Climate Uncertain,'' there is a
clear consensus of opinion in the scientific community that these
models are not intended, or capable of, predicting future impacts of
climate change on a regional basis. Even the EPA web site makes this
point.
The mere use of the foreign computer models in the National
Assessment once again, begs an answer to an obvious question: What
needs to be done to improve U.S. modeling capability? Other questions
that need answers are: How well has the current Administration been
spending our money in the climate arena? Do we have our scientific
priorities in order?
These, along with many other questions, I hope will be asked of
those testifying before you and the Committee this morning. We must
pursue a more consensus building approach to the climate change issue.
Senator Frank Murkowski and I have introduced legislation that we
believe provides a framework for national consensus--making continued
stalemate on this issue unnecessary and intolerable. We have the
vehicle to move forward. We should do so expeditiously, and with the
constructive support of the Administration.
Thank you, Mr. Chairman.
______
Prepared Statement of Hon. Frank H. Murkowski, U.S. Senator from Alaska
I want to thank Chairman McCain and the members of the Committee
for holding this hearing today to review the recent National Assessment
Report on climate change and its impacts on the United States.
The report estimates effects of climate change on various regions
of the country, and various sectors of our economy, such as agriculture
and water resources. At the heart of this report are ``potential
scenarios'' of climate change over the next 100 years predicted by two
climate models--one from Canada, and the other from the United Kingdom.
These two climate models were ``state of the art'' three years ago when
work began on this report, but it's important to note that significant
advances in our ability to model climate on regional scales have been
made since then.
These ``scenarios'' of climate change were then used to drive other
models for vegetation, river flow, and agriculture--each of these
models have their own set of assumptions and limitations reflecting
incomplete understanding of the Earth system and its component parts.
The end result of the three-year study is a 600 page report that
paints a rather grim picture of 21st Century climate. Now the
environmentalists and others in favor of the Kyoto Protocol are
shouting from the rooftops--saying that these ``potential scenarios''
mean that we should go forward with drastic and costly measures to
limit greenhouse gases.
As the Committee considers the National Assessment Report today, I
encourage you to look beyond the rhetoric to the science that underlies
this assessment--we are only just now beginning to conduct the kind of
scientific research that will allow us to determine impacts of climate
change on the regional and local scales that are most relevant to our
constituents.
For example, a reasonable test of a climate model is whether or not
it accurately simulates today's climate--the National Assessment's own
science web site displays a chart that compares rain and snowfall
predicted by the two climate models to actual measured precipitation
(see attached Figure). The areas in blue and purple reflect areas where
the model predicts more than TWICE as much rainfall as observed--if you
live in an area with 10 inches of rain, the model would predict that
you get 20 or more. Similarly, the areas in red reflect areas where the
model predicts less than HALF as much rainfall as observed--if you
actually get 10 inches of rain, the model would predict that you get 5
or less.
Now, we know that the amount of rain and snow falling within a
river basin determines river flow--which determines:
the amount of water for irrigation of crops
the health of fish species
the generation of hydroelectric power
and the water available for human use
So depending on what the climate models say, you can imagine very
different impacts--and if the models are off by 50 or 100% in either
direction, so too could be the estimates of impacts from climate change
on these sensitive areas of the environment and our economy. This is
just one example of the need for continued scientific research to
understand the entire Earth system and how it responds to changes in
atmospheric trace gas concentrations.
Nonetheless, the National Assessment has been a very useful
exercise: it shows the difficulty of estimating regional impacts of
climate change; it highlights the need for additional scientific
research (namely improved climate models and observing systems); and it
reminds us of the potential risk of climate change--a risk that we
should responsibly address through the construction of a national
energy strategy that includes consideration of climate change and its
potential risks.
The Committee on Energy and Natural Resources, which I chair, has
held a number of hearings on climate change and its economic
consequences for the United States--and the findings are not
encouraging. If we heed the environmentalists' call and ratify the
Kyoto Protocol, American consumers would see gasoline prices above
$2.50 per gallon and watch their electricity bills increase by over
85%, according to the Energy Information Administration. These
projections have withstood scrutiny and have been confirmed by numerous
other studies of Kyoto and its economic impacts.
Furthermore, the Kyoto Protocol will not lead to stabilization of
greenhouse gas concentrations in the atmosphere--the principal goal of
the Framework Convention on Climate Change signed by the U.S. in 1992.
Without developing country participation in the Protocol, greenhouse
gas emissions would continue to rise as a result of industrialization
and increased energy needs of China and India--nearly one-third of the
world's population. No matter what kinds of cuts in emissions we make,
Kyoto will not result in any meaningful difference in the climate.
As the Senate stated when it passed S. Res. 98, the ``Byrd-Hagel
Resolution'' regarding climate change, a climate treaty must include
meaningful developing country participation and must not come at
economic cost to the United States. Neither of these conditions have
been met in the current Kyoto Protocol, and it is clear to me that we
need an alternative approach to addressing the risk of climate change--
one that recognizes the global, long-term nature of the problem.
To this end, I have sponsored, with Chairman McCain and 19 other
Senators, the Energy and Climate Policy Act (S. 882) which provides a
technology-based alternative to the Kyoto Protocol. Our bill:
Creates a new $2 billion effort over the next ten years to
cost share technology development with the private sector;
Creates an Office of Climate Change within the Department of
Energy to coordinate research and development activities across
a wide range of energy technologies; and
Promotes voluntary reductions by improving the government's
system of tracking voluntary emissions reductions.
Senator Craig has also introduced a bill (S. 1776) that I have
cosponsored which complements S. 882--it addresses some issues such as
strengthening coordination between elements of the U.S. Global Change
Research Program. We anticipate including elements of Senator Craig's
bill in an amended version of S. 882 when we consider it later in the
year. I welcome interest from members of the Committee if they wish to
review our legislation and offer comments or amendments.
In summary, I believe that we should take prudent steps to address
the possible risks of climate change, but we should recognize the
global, long-term nature of the problem and respond accordingly. A
balanced portfolio of energy options, including expanded use of natural
gas and continued reliance on emissions-free nuclear and hydro power,
would produce fewer greenhouse gases than the Administration's current
energy plan. We should expand existing emissions-free technology,
including nuclear, hydropower, solar, wind and biomass, but we should
also promote new technology to trap and store greenhouse gas emissions
from the atmosphere and encourage voluntary actions to reduce
greenhouse gases and use energy more efficiently. We should also invest
in a new generation of energy technologies that can be deployed in
developing countries, preventing greenhouse gas emissions before they
occur.
The risk of human-induced climate change is a risk we should
responsibly address, and a balanced, technology-driven energy strategy
offers us the means to do so. As we consider our future national energy
strategy (which drives our greenhouse gas emissions), we now have an
excellent opportunity to address our environmental concerns at the same
time that we address our growing dependence on foreign oil.
I thank Chairman McCain and the members of this Committee for their
interest in these issues, and look forward to working with you on
establishing a balanced energy portfolio that makes good sense for our
economy, our environment, and our national security.
______
Prepared Statement of The Annapolis Center
Global Climate Modeling:
Helping to Understand Strengths and Weaknesses
Introduction
The public's and decision-makers' understanding of the strengths
and weaknesses of computer modeling of global climate is essential to
the formulation of long-term policies related to global climate change.
In the hope of facilitating better understanding of the status of
climate modeling, the Annapolis Center gathered a diverse group of
experts for discussion of the status of climate modeling and to prepare
this report.
The majority of the group's views on this general subject were as
follows:
There are a number of ``greenhouse'' gases in the earth's
atmosphere, including water, in the form of vapor,
CO2, and methane. (Water vapor is a much stronger
contributor to the natural [non-anthropogenic] greenhouse
effect than CO2.)
Atmospheric carbon dioxide (CO2) has been
increasing for more than 100 years, almost certainly in large
part because of human activity.
There are growing indications that global near-surface
temperatures have increased over the past century by about 1+F
(0.6+C). Temperatures in the lower five miles of the
atmosphere, the lower-to-mid troposphere, have increased only
slightly, if at all, in the past several decades of
instrumental monitoring.
Natural increases in atmospheric CO2 in the
Earth's past have been well documented, however, the cause-and-
effect relationships with past climate change are not clear.
The rate of increase of CO2 in the atmosphere in
the past century is greater than any previously recorded
historic rate.
How much of the observed warming is caused by human
activities and by natural climate variations is uncertain.
Climate Modeling and Simulation
How can we understand the earth's climate system and the possible
consequences of increased concentrations of greenhouse-gases in the
atmosphere? We can do some things in the laboratory, but because the
earth's climate system is so large and incredibly complex, we can
recreate only small pieces of it in the lab for extensive study. So
scientists develop computer models based on the governing physical
principles as expressed by mathematical equations that describe many of
the processes that may affect climate. Such models act as simulation
laboratories in which experiments can be performed that test various
assumptions and combinations of events. These experiments not only can
expand our knowledge, they can also develop insights into possible
climate futures.
Although there are a variety of increasingly complex climate
models, only the ``general circulation model'' (GCM, sometimes also
referred to as a global climate model) determines the horizontal
(geographical) and vertical (atmospheric and oceanic) distributions of
a group of climatic quantities, including (1) temperature, wind, water
vapor, clouds and precipitation in the atmosphere; (2) soil moisture,
soil temperature and evaporation on the land; and (3) temperature,
currents, salinity and sea ice in the ocean. The related equations are
so complex, however, that they can only be solved for specific
geographical and vertical locations, and only over specific time
intervals. For example, a typical GCM subdivides the atmosphere into
thousands of three-dimensional volumes, each having linear dimensions
of about 250 miles in the north-south and east-west directions, and a
mile in the vertical direction. The task of making these boxes smaller
is severely limited by the speed of even present-day supercomputers.
For example, decreasing the horizontal size of a GCM from 250 to 25
miles would increase the required computer running time by a thousand
fold--from about 2 weeks to more than 30 years of run-time to compute
the resulting change in the equilibrium climate of the model!
The Uses of Climate Models
Until the advent of supercomputers, our attempts at climate
modeling were rudimentary. That situation changed roughly 25 years ago.
Much of the recent attention by the public and decision-makers on
climate change has been due to measurements indicating that warming has
been occurring near the Earth's surface over the last century and to
relatively recent projections from GCMs.
Climate varies naturally over both short and long time scales,
sometimes rather dramatically over a few years or decades. This rapid
variability was experienced in Europe during the Little Ice Age of
1400-1850. To understand climate change, scientists must understand the
detailed nature of the extremely complex climate system. While we have
learned a great deal, there is still much we do not know. Climate
models today can give us insights into what might happen under various
assumed situations.
Currently, there are about 30 GCMs being developed and/or used by
research groups around the world. Many of these models are related,
with the differences among the models lying in the natural processes
they include and how they integrate and treat these processes within a
specific model.
As discussed above, computer models are necessary in the study of
climate change because of the extraordinary complexity and number of
the physical processes that are embodied in the climate system. Some of
the factors that affect climate include:
the concentrations of gases and aerosols;
interactions between the atmosphere, the biosphere, and
oceans;
volcanic activity; and
interactions of components within the atmosphere and ocean
themselves.
The growth of computing capacity has allowed scientists to
integrate complex climate-system processes into single computational
frameworks. These frameworks can be used to develop an increasingly
more comprehensive, but still incomplete, overall picture of the global
climate system.
The Roles of GCMs
The general uses of GCMs are:
First, the building and running of a model is a process by which
theory and observations are mathematically evaluated, codified and
integrated in a computer program. Models can thereby be used to
identify needed refinements in theory and observation. Model building
is a long process of back and forth comparisons between analytical
description (``theory'') and field studies (``observational data'').
These comparisons include end-to-end efforts to correlate observational
findings with improvements in model representations.
Second, climate models are used to identify and then assimilate
observational measurements that are initially incomplete. These
measurements can then be used to derive more consistent, spatially
specific estimates of meteorological quantities. Such model-assimilated
data have proven to be of great utility to the research community in
better understanding the observed and potential variability of the
climate system.
Third, models can be used to focus observational activities. In
regions where data are sparse, models can be used to define the
frequency, coverage, and type of measurements that may shed the most
light on the physics, chemistry and the composition of the atmosphere.
Fourth, climate models have recently predicted a few climate
anomalies up to a year in advance. These model predictions, which are
increasing in accuracy, incorporate information on the current state of
the oceans and atmosphere. Predictions of El Nino and La Nina events
and climate anomaly patterns associated with these phenomena have
proven reasonably accurate and there is potential for this type of
model prediction to be extended out beyond a year.
Fifth, climate models can be used to develop scenarios of possible
future states of the climate system, given a specified set of
assumptions (e.g., the future quantities of greenhouse gases, including
ozone trends and aerosols). Such climate scenarios can then be used to
develop projections of possible climate-related impacts on human and
natural systems. Models currently show large-scale climatic response to
increased greenhouse gas levels: for instance, (1) there may be some
warming at the surface, warming of the troposphere, and some cooling in
the stratosphere; (2) there may be greater warming at high latitudes
than at low latitudes; and (3) there may be an increase in low level
humidity over the oceans. Such fingerprints of human-induced climate
change have been compared with the observed climate to help detect its
changes and attribute its causes.
From the GCM-based projections of climate change, analysts can
begin to evaluate the potential impacts on market and non-market
sectors of society. As these impact models become more sophisticated,
increasingly better pictures of what might happen under different
scenarios will develop. More research on impacts will help countries
identify the seriousness of possible climate change and allow them to
study the cost-benefits of various response options.
In addition, models can be used to facilitate an understanding of
the lag time between causes and effects associated with human as well
as natural causes of climate change. It is essential to keep in mind
that model projections depend on the sophistication of the model: the
estimates in the model, the assumptions used by the model, and what in
nature is not yet understood and therefore not covered in the model.
This is why the climate research community generally places so much
emphasis on verifying model results with actual data. By exploring sets
of these model projections, the policy community can begin to discuss
the effects that policies, aimed at reducing greenhouse gases, might
have on climate, humans, and economies.
Models & Decision-Making
Existing GCMs can make ``what if'' projections of future global
climate possibilities because they are the best available tools, even
though they are currently limited in resolution and completeness.
Regionally specific information is ultimately needed because, for
example, while U.S. citizens have interest in what happens to the
planet as a whole, they are especially interested in what happens to
the U.S. and to their own neighborhood. Global climate projections from
different models show a range of effects. The range of effects is
largest for smaller regions. Partly, this is due to the natural local
variability of climate and partly this is due to scientific
uncertainties.
Just as global climate models have advanced, so have global
economic impact models for estimating costs and benefits. Integrated
assessment models, which take into account chains of events (if ``A''
happens, then results ``B'' could occur, but if ``A'' does not happen,
then ``C'' will occur), are a tool to help understand long-term costs
and benefits.
Limitations of Models
Having discussed the uses and strengths of GCMs, one should not
assume that they do not have weaknesses--in fact, some scientists would
state that the weaknesses are so great as to question their value in
near-term decision-making. Some of the features of the GCMs are less
robust than others, partly because there is disagreement between the
models about predicted climate changes. Furthermore, even if the models
agreed, it does not necessarily make them correct.
Phenomenological Feedbacks
Much of the uncertainty in current climate models is associated
with ``feedbacks''--how various phenomena interact with one another.
Feedback mechanisms are clearly important. Climatologists agree that,
without these feedbacks, a doubling of CO2 would give about
a 1.8+F (1+C) rise in global-average temperature. Many phenomena have
large impacts on others, some amplifying and some dampening effects.
Some extremely important phenomena, the feedback consequences of which
we do not fully understand, are the following:
Clouds;
Ice;
Land surface processes;
Ocean effects;
Biological processes;
Physical and chemical reactions in the atmosphere;
Particulates;
Solar cycle effects; and,
Tropical convection and rainfall.
These phenomena are not yet adequately understood in isolation, let
alone in combination with other factors. Thus, scientists must utilize
approximations, estimates of aggregate regional effects, or ignore some
phenomena all together for the time being. Other suspected feedback
mechanisms are yet to be described or modeled.
For example, the role of clouds and water vapor in climate models
is not well understood; yet water vapor is the most significant
greenhouse gas in the natural (unperturbed) atmosphere and dramatically
affects cloud cover and the transfer of radiant energy to and from the
Earth's surface.
Also, modeling the impact of clouds is difficult because of their
complexity and compensatory effects on both weather and climate. Clouds
can reflect incoming sunlight and therefore contribute to cooling, but
they also absorb infrared radiation that would otherwise leave the
earth, thereby contributing to warming.
Parameters
Models utilize observational data to adjust various model
parameters to help make such parameters more realistic. ``Tuned''
models, however, cannot be validated by the data for which they were
adjusted and must be validated by independent means.
As previously mentioned, the equations related to the climate to be
modeled are so complex that they can only be solved at specific
geographical and vertical locations, and only over specific time
intervals. The limit on horizontal size imposed by present-day
supercomputers also limits the physical processes that can be
explicitly included in a GCM. As discussed above, GCMs using today's
supercomputers explicitly include physical processes having horizontal
sizes of approximately 250 miles and larger. Worse yet, the physical
processes smaller than 250 miles cannot be ignored because their
effects can significantly impact climate and climate change. Thus,
climate modelers face the dilemma that their models cannot resolve the
small-scale physical processes and they cannot ignore their effects.
This is one, if not the major difficulty in modeling the Earth's
climate. The approach taken to overcome this problem is to determine
the effects of the small-scale physical processes on the larger scales
that can be included in a GCM using information on those larger scales
and statistical relationships. This approach is called
``parameterization.'' The principal differences among GCMs lie in their
approaches to parameterization, particularly in the case of cloud and
precipitation processes. These parameterization differences have a
significant influence on differences in climate sensitivity--the change
in the equilibrium global-mean surface temperature resulting from a
doubling of the CO2 concentration--between various GCMs.
Testing Models
One way that models are tested is to use them to reproduce past
events and variations. The earth's climate has been changing for
millions of years but we do not have detailed data on those changes
because humankind was not acquiring relevant data until relatively
recently. As such, we cannot accurately truth test climate models over
past periods of time beyond much more than a hundred years. Thus, we
are asking these models to assist us in decision-making in an
environment of considerable scientific uncertainty. There is, however,
significant effort underway to compare the general nature of model
simulations of pre-historic time periods against data from proxies
(e.g., tree-ring widths, borehole temperatures, and oxygen isotopes in
sediments) of past climates.
Human Resources
Compared to intermediate and smaller modeling efforts, such as
those aimed at understanding the behavior of a particular climate
process over a single locality, insufficient U.S. and international
resources for research and computer hardware are being devoted to high-
resolution global climate modeling.
Data
Instrumental temperature measurements of varying quality exist for
about 135 years. Relatively crude but useful information before then
has been obtained from proxy data such as the width of tree rings and
the abundance of certain isotopes trapped in ice cores taken from the
ice caps and glaciers and in sediment cores taken from the deep sea and
lakes.
Climate data are routinely collected for weather prediction. Much
of this data gathering was not designed to detect subtle trends that
occur on decadal or longer time scales. For climate modeling, we need
more accurate and extensive data than even currently used in weather
prediction. There is also a need for better organization and long-term
archiving of climate data.
Advancement of Models
Model development has progressed considerably in the past decade.
However, though there have been downward modifications in estimates of
future climate change (e.g., through the inclusion in models of the
effects of aerosol cooling), the limits of uncertainty in possible
global-average warming for a future doubling of CO2 have not
been narrowed; that uncertainty has been in the 2.7-8.1+F (1.5-4.5+C)
range for the past 20 years for most GCMs.
While the capacities and speed of supercomputers have progressed
dramatically in recent years, climate models remain constrained by
current computational capacity. In fact, the leading climate models are
no longer in the United States because U.S. researchers do not have
access to the more powerful Japanese computers that other nations
(i.e., Canada, Japan, United Kingdom) are using. Current computer
capabilities applied to climate modeling are modest compared to what is
needed to run high-resolution simulations using GCMs. Current computer
limitations require that we settle for grid sizes that are much larger
than needed to model some important phenomena such as tropical
convection and precipitation.
The participants in the discussion agreed with the National
Research Council's Report ``Capacity of U.S. Climate Modeling (1998)''
statement of the Council's ``summary results'', if not all the details
of its Report.
Conclusions
There are significant uncertainties in predicting future climates
as a consequence of (a) natural climate variability; (b) the potential
for uncertain or unrecognized climatic forcing factors (e.g., explosive
volcanism, new or unknown anthropogenic influences, etc.); and (c)
inadequate understanding of the climate system. We must expect that new
observations or results from studies of global climate processes may
yield information that causes us to re-evaluate and improve the
capability of climate models. Our estimates of the credibility of
climate system models can be, of necessity, consistent only with known
facts and only based on the ``best'' current knowledge.
Projections vs. Predictions
Thus, it was the consensus of the experts convened by the Annapolis
Center that climate models may never be able to make greenhouse-warming
PREDICTIONS with certainty because of the enormous number of variables
involved and the uncertainty inherent in the future. On the other hand,
models of greenhouse warming are essential in the learning process.
Climate models can be used for making PROJECTIONS based on various
assumptions that in turn may be useful in understanding the
consequences of various human activities and policy alternatives. When
such projections will represent possible real climate futures is
difficult to judge because of the enormous scientific uncertainties
involved.
CLIMATE PROJECTIONS are ``what-if'' scenarios about what might
happen under a set of ASSUMED conditions. Projections may change as
more knowledge is acquired.
When weather forecasters make predictions one day or a week in
advance, they can verify their predictions soon thereafter. Climate
projections for the next century cannot be verified so easily.
Continued climate warming year after year is not likely to occur.
Periods of apparent cooling, however, would not necessarily mean that
the Earth was not slowly warming over the long term. Similarly, if we
were to experience warming year after year, we should not assume that
man-made climate change was the primary or only cause.
Though Better Understood, We Still Have A Long Way To Go
Global climate science has progressed significantly in recent years
but our lack of knowledge is still great. A major vehicle for
understanding the enormously complex global climate system has been
computer modeling. Today's GCMs have developed rapidly relative to
earlier models and provide improved estimates of what may happen in the
future. Many believe that such models are still in a relatively early
stage of development. Nevertheless, GCMs are important research tools
that can help to focus the research and measurements needed to better
understand climate change. Climate modeling will be increasingly more
valuable as models and our understanding of basic processes are
improved.
Models of climate changes are still evolving because we do not yet
completely understand or model everything that can or will affect
climate. Scientific uncertainty will always be a component of modeling
climate change. Our challenge is to reduce this uncertainty.
Because of the Uncertainty, Care Must Be Used in Decision-Making
Care must be taken when using the results of climate models for
major public policy decisions because of the existing uncertainty, as
well as our lack of knowledge about important physical and chemical
reactions in the atmosphere and oceans.
Adapt Via ``Act-Learn-Act''
Because man-made greenhouse gas emissions are likely to continue to
increase in the future, the workshop participants endorse adaptive and
affordable management strategies, such as ``act-learn-act,'' that are
robust against what we do no yet know. We will surely be learning more
about climate change over time. As we learn more, we must revisit
greenhouse-related policies and adjust them accordingly.
______
Prepared Statement of Dr. Peter B. Rhines, Professor,
University of Washington
Climate change takes on real force when it combines with human
activity. It produces multiple and compounded changes of the physical
environment, and of ecosystems. The U.S. feels these impacts from
beyond national boundaries, from the global atmosphere and ocean.
There are many points of contention: between modification of our
environment and accommodation to it; between natural and human-induced
climate change; within the scientific debate, between the need for
prediction and the need for diagnosis. Improved observation and
understanding of the current and past states of the environment (the
atmosphere, ocean and land surface) may be just as important as
attempts to predict its future.
As Dr. Schmitt has earlier this morning described, the ocean plays
a particularly interesting role in climate: it dominates the storage of
heat and carbon and water; it also contains a significant fraction of
global biological activity: photosynthesis and respiration. It is a
well-spring of diversity, harbors newly discovered forms of life, and
in the search for natural pharmaceuticals it is richer than the land.
Large-scale oscillations of climate. El Nino/Southern Oscillation
(ENSO), centered in the tropics, is an `argument' between ocean and
atmosphere which radiates across N. America. With enormous impact on
temperature, rainfall, storms, flooding, drought, there is some good
news in an el nino winter, and much bad news.
In the far northern Atlantic Ocean, the paths followed by intense
storms over the ocean have moved north since the early 1970s. These
storms intensify as they suck heat from the ocean. This is a part of
the so-called North Atlantic Oscillation (NAO), which can switch
regimes from one month to the next, or from one 30 year period to the
next: it has an element of unpredictability. It is intimately related
to the jet stream and polar vortex, a `tall' mode that reaches to the
stratosphere. The NAO is one of several important patterns of
oscillation of the atmosphere outside of the tropics (others include
north-south `annular oscillation' of the jet-stream system in the
Southern Hemisphere, and a great wave round Antarctica that appears to
be coupled between ocean and atmosphere).
In addition to its many impacts on weather, drought and flooding,
the NAO is involved in the great, deep overturning circulation of the
ocean. The temperature and salinity of the oceans both condition its
fluid density . . . its ability to sink. It is at high latitude that
the ocean is chilled by the atmosphere, and in rare and small regions,
water sinks to the abyss. This global system fulfills the need for heat
to be transported from the warm latitudes to the cold, where it
radiates to space.
Nearly horizontal layering of the oceans, with dense waters sinking
beneath buoyant surface waters, is the result of this `heat engine' and
it is of great consequence to the distribution of ocean life.
Photosynthetic life needs sunlight and nutrients. By controlling the
flow of nutrients from their rich store at depth, upward to the sunlit
surface, life of the ocean is determined by its patterns of its up/
down, north/south circulation. This `meridional overturning
circulation' provides a severe challenge to computer models, because of
the small yet essential features and the complex shape of the solid
Earth. While current computer models have many inaccuracies, they are
increasingly being subjected to the acid test of focused, small scale
seagoing observational programs.
ENSO and NAO are examples of the possible expression of global
warming in `modes' . . . that is patterns of ocean and atmosphere
response with warm and cold, wet and dry. The Titantic sank in 1912,
during a cold period that encouraged icebergs to reach southward into
shipping lanes. There followed two major periods of global warming this
century, the 1930s-40s and 1970s-90s, which in fact correlate with
phases of the NAO. These modes are good tests of computer models of
climate, and indeed are the subject of intense simulation work at
present.
Northern Asia and Canada experienced some of the most intense
warming in the 1990s, dominating the global average: we in the U.S.
have not yet seen the full force of warming. The northern Atlantic
actually has cooled for many years, as cold, Arctic air blew from
Canada with increased vigor. Greenhouse warming is expected on average
to be initially severe in the Arctic, and to increase the water vapor
in the atmosphere. In N. America, increased precipitation and
streamflow out into the ocean has developed. Together with the long
feared, and now observed, thinning and meltback of the Arctic sea ice,
these events are portentous.
Abrupt climate change. The paleoclimate observations, both from
sea-floor sediment cores, glacial ice cores, record remarkable periods
of rapid change in the distant past, particularly during ice-age
glaciation and the transition out of it. Both the increasing input of
fresh water on top of the ocean, and the warming itself, can resist the
sinking and global deep circulation described above. Communication
between land surface, Arctic, and Atlantic ocean is important to the
distribution of low-salinity water, and it is correlated with the NAO.
Mathematical models and computer models of climate predict a slowdown,
by up to 50%, of this global circulation in the coming decades. Such
changes can be called abrupt in the great scheme of things. A new
National Research Council study on abrupt climate change is underway
this summer.
The ocean ecosystem represents an important, in some ways dominant,
part of global photosynthesis and respiration. Ocean circulation and
its layering into dense deep waters and buoyant surface waters largely
control the distribution of life in the sea. Disappearance of cod from
Atlantic fisheries has a strong relation to over-fishing, yet these
fish are very sensitive to temperature. Recovery of cod stocks has been
slow, even when fishing grounds closed down. Salmon fisheries in the
north Pacific have seen very long (~50 year) cycles, under a multitude
of pressures from declining quality of rivers and streams, and climate
change (the so-called Pacific Decadal Oscillation, or PDO). This summer
Coho salmon returned to Lake Washington in great numbers, for the first
time in a decade, yet other salmon species are now on the endangered
list. Overall, 11 of the 15 most important global fisheries are in
trouble, and the world fish catch has begun to decline after rising
six-fold between 1950 and 1996. It is a classic case of compounding of
causes: over-fishing puts stress on fish populations, making them
sensitive to modest climate change.
Storms. Severe storms, hurricanes, tornados, the super-novae of
weather, are of particular importance. Loss of life in underdeveloped
countries and economic loss in the U.S. are both striking. A tropical
cyclone (dynamically similar to a hurricane) in the Indian Ocean hit
land in Bangladesh in November 1971; its 30 foot-high storm surge
inundated the low-lying river delta, causing between 250,000 and
500,000 fatalities. In the U.S. Hurricane Andrew, in 1992, was one of
the most costly natural disasters in history. A direct hit of a major
hurricane on Miami could cost more than $70B in property damage, owing
to the intense coastal population increase and development of coastal
real estate. Hurricane Mitch, in 1998, showed the world how capricious
and destructive these storms are in the less-developed world. Following
an unexpected path southward, then sitting over the mountains of
Honduras and Nicaragua, Mitch destroyed villages and cost more than
10,000 lives through endless rainfall, flooding, and erosion. It nearly
destroyed the economies and social infrastructure of these countries.
Hurricane paths and their intensity are correlated with el nino
cycles, and with another key tropical oscillation, the Madden-Julian
Oscillation. Hurricanes (and tropical cyclones) take their energy from
the heat of the tropical ocean. They do so surprisingly rapidly, and
have been observed to intensify in passing over the Gulf Stream and
warm eddies (only 50 miles wide) in the Gulf of Mexico. Long lasting
effects are inland flooding, pollution and sedimentation, which destroy
habitats in estuaries and marshes. Their connection with global warming
is less clear. Model studies suggest a 5%-12% increase in hurricane
wind-speed for a 2 degree C rise in sea-surface temperature, but this
is very uncertain.
Changes in normal weather, for example, more intense rainstorms,
have been linked to ENSO, NAO and other global climate modes. Possible
links exist back to global warming through these modes of oscillation,
as well as more directly, through the changing levels of cloudiness.
At every turn in this discussion we must weigh the relative
advantages of prevention, protection, and treatment in the aftermath.
Amartya Sen, an economist at Cambridge University, argues that
destruction from climate and storms is most severe in the aftermath:
that stockpiling of food and creation of jobs programs for the poor are
important in preserving human life . . . as much so as protection from
the storm on the day, itself.
Coastal Ocean. The coastal ocean, the water on the continental
shelves and in estuaries, is a small part of the global ocean, yet is
the home of roughly one half of oceanic biological productivity
(roughly 25% of global primary biological productivity). It is the site
of much diversity, and close involvement with human populations, which
are increasingly concentrated near the seacoast. It is also the site of
80 to 90 percent of the global fish catch. Estuaries, where rivers meet
the sea, are a sort of pumping machine in which river-flow and tidal
stirring combine to suck water in from the deep ocean, supplying the
region with nutrients: to their benefit, estuaries flow in and out at
rates much greater than (as much as 50 times) the river-flow that
drives them. Nutrient sources from rivers are often a small
contribution, yet in some estuaries, agricultural practices are loading
the estuaries with nitrogen and phosphorus, as well as viruses and
bacteria. Chesapeake Bay seasonally teeters on the edge of hypoxia, a
reduction of oxygen to the point where fish can no longer live, when
stratification, layering of the water by density, and nutrient inflow
are both high.
The coasts are what we call `potential vorticity guideways' along
which climate change can be signaled rapidly (for example, from an el
nino event on the Equator, poleward along the North and South American
Pacific coasts). With a complex of local influences, human and natural,
the coastal ocean is undergoing rapid change. Yet, at the same time,
global climate change is strongly felt in this region. A third, severe
effect is the colonization of the coastal ocean (and lakes and rivers)
by new species introduced by ship traffic. Ships carry ballast water
from one continent to another, discharging it and its biological cargo
near the coast. The highly diverse coastal ecosystem, after evolving in
relative isolation, is suddenly invaded.
It is hard to say in detail what is the time- and space-variability
of ocean biology and its impacts on the health of humans, fish and
algae. This is because we have not yet invested in baseline
observations of the coastal ocean. But we observe numerous regional
hot-spots, as with the dinoflagellate gymnodinium catenatum transported
to Australia from Asia, and the Asian clams that have taken over San
Francisco Bay.
Both river- and deep-sea inputs to estuaries change with climate.
For example, during El Nino, riverflow decreases in some regions, thus
decreasing the nutrient supply from this source. At the same time
coastal winds change and this change can alter the supply of nutrients
to the estuary as more or less nutrient rich water is pulled up from
the deep ocean to the estuary mouth. Variation of the health of
fisheries, such as oysters in the Pacific Northwest, has been shown to
depend on the frequency and strength of El Nino. Because of the link to
offshore waters, estuaries can also be expected to show evidence of
longer term climate change such as the PDO.
Major rivers can exhibit these sensitivities strongly. In the
Pacific Northwest the largest river is the Columbia. The plume from the
Columbia can stretch several hundred kilometers from the river mouth--
to the Strait of Juan de Fuca in the north and to San Francisco in the
south. The size of the plume is controlled in spring by the amount of
snow pack received by the region in the preceding winter. For example,
snowpack was high in 1999 during la nina. In such years, the plume
floods other nearby estuaries, substantially reducing the salinity and
nutrients in those estuaries, dramatically altering the environment
encountered by emerging salmon smolts and entering juvenile crab
larvae. In years with lesser snowpack, the Columbia plume likely has a
more southwestward orientation and may have much less effect on local
estuaries. Long term effects on the fisheries might be expected due to
these and other such climate effects and are the subject of current
research.
Human health. Along with colonization of the coastal ocean by new
species there are increasing problems involving toxins. Harmful algal
blooms are occurring more frequently. They involve both local human
causes (nutrient loading, turbid water), and physical ocean changes
(temperature, stratification, upwelling, rainfall). While mortality is
not often widespread, illness and economic loss from closure of
shellfish beds is. Estimates of the loss to the fishing industry from a
single Pfiesteria outbreak, in Chesapeake Bay in 1996, were $20M. The
degree to which global climate change is involved, is not yet known.
An example of a pressing public health and economic problem is the
diatom in the genus Pseudonitzschia that cause domoic acid poisoning
(DAP), also known as amnesic shellfish poisoning (ASP), and
dinoflagellates in the genus Alexandrium that are the source of
paralytic shellfish poisoning (PSP). Toxic outbreaks along the U.S.
coast can be highly localized or can extend over several hundred miles
and last for several months. Both the occurrence of such toxic algal
blooms in the offshore coastal waters and the delivery of the toxic
algae to coastal beaches and to coastal estuaries is thought to depend
on wind speed and direction as well as coastal water properties and
hence have a direct link to climate changes along the U.S. coast. Near
the Strait of Juan de Fuca, the physical oceanography of the coastal
circulation has been linked with the appearance of HABs at the coast. A
detailed study of the toxic dinoflagelate gymnodinium breve shows its
development in the warm, broad shallows of the Gulf of Mexico, and its
transport in the Gulf Stream system as far as North Carolina, where it
has come to shore.
A major outbreak of cholera developed in coastal Peru, during an
extended el nino event in 1991, and thereafter quickly appeared to
neighboring countries. In the first 3 weeks, 30,000 cases and 114
deaths were reported. Cholera lives dormant in the sea as vibrio
cholerae, associating itself with mucous membranes of the copepod.
There is an apparent relationship between warm sea-surface temperature
and cholera there and in Bangladesh. The association of climate with
disease is thus plausible, yet there are several possible routes, for
el nino rainfall alters sanitation on shore as well as disturbing and
warming the coastal ocean.
Cholera is a disease that may illustrate the association of
virulence with transmission rate. In evolutionary biology, Paul Ewald
of Amherst College argues that cholera and many slowly developing human
diseases have evolved so as to maximize their own transmission. Thus,
with poor sanitation in the under-developed world, cholera is rapidly
transmitted and very virulent. In countries with good sanitation
cholera exists in a much more benign strain, adapted to very slow
transmission. This message suggests that global climate change and
human activity (like introduction of `exotic' species by ship traffic)
both could conspire to increase the virulence of toxic viruses and
bacteria in the environment.
There is a tension throughout this debate on global change, between
advocates of public health, social infrastructure, economics of the
recovery on the one hand, and advocates of mitigation of climate change
(and its role in disease), and environmental science, on the other.
Regardless of the balance struck in resolution of this debate, there is
value in observing our environment, predicting its future, AND
assessing its current behavior.
New technologies. A remarkable chain of technological discovery has
focused on observations of the global environment. These are moored and
drifting and self-propelled vehicles in the ocean, with a range of
sensors for physical, biological and chemical substances; orbiting
satellites that probe both oceans and atmosphere; sea-floor and moored
`observatories' that allow us to `explore in time' as well as space.
The importance of establishing long-term measurement sites for climate
studies cannot be overstated (the TAO array of moorings in the Pacific,
perhaps the largest scientific instrument ever built, has shown us the
inner workings of el nino). Molecular biology gives a remarkable tool
for studying the function and evolution of ecosystems. Computer models
of the climate system have become the centerpiece for ideas and
observations, and computing power continues to increase steadily
(though sometimes delayed by political constraints).
These new sensors and platforms give us eyes for viewing climate,
computers and the internet give us a global central nervous system, but
we also need the will to observe and understand the environment as it
is assaulted by accelerating natural and human-induced change.
Currents and upwelling of cold, nutrient rich water along the U.S. west
coast
Sea-surface temperature (Oregon State University)
Evidence of a red tide on the West Florida Shelf: Nov 1978, red =
chlorophyll
a > 3 g/l (Florida Marine Inst.)
Northern Atlantic (Labrador Sea) salinity at three depths (2000m,
3500m, 1500m top to bottom). Salinity declines as fresh water input at
the surface has increased with intense, cold forcing by the North
Atlantic Oscillation. I. Yashayaev, J. Lazier Bedford Inst. of
Oceanography, P. Rhines (Univ. of Washington)
Dissolved nitrate in the Atlantic Ocean, along a section from
Antarctica (left) to Iceland. High concentrations of this nutrient
occur deep in the ocean, and in the Southern Ocean. Near the surface
nitrate is almost absent, evidence of active ecosystem growth at the
top of the ocean. The global ocean circulation must bring nitrate up to
the surface, and controls the distribution of life (WOCE program).
______
Climate Policy--From Rio to Kyoto: A Political Issue for 2000--and
Beyond
Hoover Institution Essay by S. Fred Singer
Executive Summary
Within the United States, global warming and related policy issues
are becoming increasingly contentious, surfacing in the presidential
contests of the year 2000 and beyond. They enter into controversies
involving international trade agreements, questions of national
sovereignty versus global governance, and ideological debates about the
nature of future economic growth and development. On a more detailed
level, determined efforts are under way by environmental groups and
their sympathizers in foundations and in the federal government to
restrict and phase out the use of fossil fuels (and even nuclear
reactors) as sources of energy. Such measures would reduce greenhouse-
gas emissions into the atmosphere but also effectively deindustrialize
the United States.
International climate policy is based on the 1997 Kyoto Protocol,
which calls on industrialized nations to carry out, within one decade,
drastic cuts in the emission of greenhouse gases (GHG) that stem mainly
from the burning of fossil fuels. The Protocol is ultimately based on
the 1996 Scientific Assessment Report issued by the Intergovernmental
Panel on Climate Change (IPCC), a U.N. advisory body. The IPCC's main
conclusion, featured in its Summary for Policymakers (SPM), states that
``the balance of evidence suggests a discernible human influence on
global climate.'' This widely quoted, innocuous-sounding but ambiguous
phrase has been misinterpreted by many to mean that climate disasters
will befall the world unless strong action is taken immediately to cut
GHG emissions.
This essay documents the inadequate science underlying the IPCC
conclusions, traces how these conclusions were misinterpreted in 1996,
and how this led to the Kyoto Protocol. I also discuss some fatal
shortcomings of the Protocol and the political and ideological forces
driving it.
The IPCC conclusion is in many ways a truism. There certainly must
be a human influence on some features of the climate, locally if not
globally. The important question--the focus of scientific debate--is
whether the available evidence supports the results of calculations
from the current General Circulation Models (GCMs). Unless validated by
the climate record, the predictions of future warming based on
theoretical models cannot be relied on. As demonstrated in this essay,
GCMs are not able to account for observed climate variations, which are
presumably of natural origin, for the following reasons:
1. To begin with, GCMs assume that the atmospheric level of carbon
dioxide will continue its increase (at a greater rate than is actually
observed) and will more than double in the next century. Many experts
doubt that this will ever happen, as the world proceeds on a path of
ever-greater energy efficiency and as low-cost fossil fuels become
depleted and therefore more costly.
2. Next, one must assume that global temperatures will really rise
to the extent calculated by the conventional theoretical climate models
used by the IPCC. Observations suggest that any warming will be minute,
will occur mainly at night and in winter, and will therefore be
inconsequential. The failure of the present climate models is likely
due to their inadequate treatment of atmospheric processes, such as
cloud formation and the distribution of water vapor (which is the most
important greenhouse gas in the atmosphere).
3. The putative warming has been labeled as greater and more rapid
than anything experienced in human history. But a variety of historical
data contradicts this apocalyptic statement. As recently as 1,000 years
ago, during the ``Medieval climate optimum,'' Vikings were able to
settle Greenland. Even higher temperatures were experienced about 7,000
years ago during the much-studied ``climate optimum.''
The IPCC's Summary for Policymakers tries hard to minimize the
inadequacy of the GCMs to model atmospheric processes and reproduce the
observed climate variations. For example, the SPM does not reveal the
fact that weather satellite data, the only truly global data we have,
do not show the expected atmospheric warming trend; the existence of
satellites is not even mentioned.
The scientific evidence for a presumed ``human influence'' is
spurious and based mostly on the selective use of data and choice of
particular time periods. Phrases that stress the uncertainties of
identifying human influences were edited out of the approved final
draft before the IPCC report was printed in May 1996.
A further misrepresentation occurred in July 1996 when politicians,
intent on establishing a Kyoto-like regime of mandatory emission
controls, took the deceptively worded phrase about ``discernible human
influence'' and linked it to a catastrophic future warming--something
the IPCC report itself specifically denies. The IPCC presents no
evidence to support a substantial warming such as calculated from
theoretical climate models.
The essay also demonstrates that global warming (GW), if it were to
take place, is generally beneficial for the following reasons:
1. One of the most feared consequences of global warming is a rise
in sea level that could flood low-lying areas and damage the economy of
coastal nations. But actual evidence suggests just the opposite: a
modest warming will reduce somewhat the steady rise of sea level, which
has been ongoing since the end of the last Ice Age--and will continue
no matter what we do as long as the millennia-old melting of Antarctic
ice continues.
2. A detailed reevaluation of the impact of climate warming on the
national economy was published in 1999 by a prestigious group of
specialists, led by a Yale University resource economist. They conclude
that agriculture and timber resources would benefit greatly from a
warmer climate and higher levels of carbon dioxide and would not be
negatively affected as had previously been thought. Contrary to the
general wisdom expressed in the IPCC report, higher CO2
levels and temperatures would increase the GNP of the United States and
put more money in the pockets of the average family.
But even if the consequences of a GW were harmful, there is little
that can be done to stop it. ``No-regrets'' policies of conservation
and adaptation to change are the most effective measures available.
Despite its huge cost to the economy and consumers, the emission cuts
envisioned by the Kyoto Protocol would be quite ineffective. Even if it
were observed punctiliously, its impact on future temperatures would be
negligible, only 0.05+C by 2050 according to IPCC data. It is generally
agreed that achieving a stable level of GHGs would require much more
drastic emission reductions, including also by developing nations. To
stabilize at the 1990 level, the IPCC report calls for a 60 to 80
percent reduction--about twelve Kyotos on a worldwide basis!
Finally, the essay attempts to trace the various motivations that
led to the Kyoto Protocol. It concludes that U.S. domestic politics
rather than science or economics will decide the fate of the Protocol;
in particular, the presidential elections of 2000 will determine
whether the United States ultimately ratifies the Protocol, which would
be essential for its global enactment. Conversely, informed debate
about the Protocol can influence the outcome of the elections.
______
Yale University, School of Forestry and Environmental
Studies,
New Haven, Connecticut, July 12, 2000.
Senator John McCain
Committee on Commerce, Science, and Transportation
United States Senate
Washington, D.C.
Dear Senator McCain:
In response to your invitation to speak to the Senate Committee on
Commerce, Science, and Transportation, I would like to submit the
following material as part of the written record. Over the last five
years, I have been working with a distinguished group of researchers
from across the United States measuring the impacts of climate change
on the U.S. economy. The initial study, edited by Robert Mendelsohn and
James Neumann and published in 1999 by Cambridge University Press, was
entitled ``The Impact of Climate Change on the United States Economy.''
A subsequent book entitled ``Global Warming and the American Economy: A
Regional Assessment of Climate Change'' is being prepared for
publication at present. Following is the introduction and the synthesis
of results of this new book.*
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* The information referred to has been retained in the Committee
files.
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The critical insight of both of these new books is that adaptation
matters. Empirical research indicates that households and firms will
respond to climate change and reduce damages and enhance benefits.
Coupled with more careful modeling of dynamic effects, carbon
fertilization, and ecosystem change, the new results are far more
optimistic than the old studies. These estimates do not include
nonmarket effects in health, ecosystem change, and aesthetics, but it
is not clear that these nonmarket effects will be large in the United
States.
Climate change is likely to result in small net benefits for the
United States over the next century. The primary sector that will
benefit is agriculture. The large gains in this sector will more than
compensate for damages expected in the coastal, energy, and water
sectors, unless warming is unexpectedly severe. Forestry is also
expected to enjoy small gains. Added together, the United States will
likely enjoy small benefits of between $14 and $23 billion a year and
will only suffer damages in the neighborhood of $13 billion if warming
reaches 5C over the next century. Recent predictions of warming by 2100
suggest temperature increases of between 1.5 and 4C, suggesting that
impacts are likely to be beneficial in the U.S.
The impact of warming depends upon the initial temperature of each
region. With mild warming of 1.5 C, every region benefits from warming.
The average American would enjoy benefits of about $100/yr. However,
with 2.5C warming, the cooler northern regions of the country benefit
far more than the warmer southern regions. The average citizen in the
north would enjoy benefits of about $80/yr whereas southern citizens
would enjoy average benefits of only about $6/yr. If warming rises to
5C, the benefits in the north shrink to about $40 per person, but
citizens in the south may suffer damages from $120 to $370 per person.
In summary, climate change does not appear to be a major threat to
the United States for the century to come. There is little motivation
for expensive crash programs to curb short term emissions of greenhouse
gases. The focus of mitigation policy should remain on inexpensive ways
to control global emissions over the next century.
Sincerely,
Robert Mendelsohn,
Edwin Weyerhaeuser Davis Professor.
TABLE 1 National Impacts
Sector Old Results New Results
Agriculture -17.5 to -1.1 19.6
Forestry -3.3 to -0.7 3.7
Water -7.0 to -15.6 -2.2
Coastal -7.0 to -12.2 -0.2
Energy -9.9 to -0.5 -5.8
TOTAL -44.7 to -13.8 15.1
Sources: Nordhaus [1991], Cline [1992], Fankhauser [1995], Tol [1995], Mendelsohn [2000].
Regional Impacts
(Billions of USD/yr) 2.5C, 7% Precipitation Scenario
Sector
Region Agr For Ene Coa Wat Total
Northeast 2.6 1.9 -0.4 -0.1 0.0 4.0
Midwest 5.4 1.1 -0.1 -0.0 -0.0 6.4
N. Plains 2.8 0.6 -0.1 -0.0 -0.1 3.2
Northwest 1.1 -0.1 1.4 -0.0 -1.7 0.7
Southeast 4.2 -0.8 -3.0 -0.1 -0.0 0.3
S. Plains 2.1 0.6 -2.4 -0.0 -0.2 0.1
Southwest 1.4 0.4 -1.2 -0.0 -0.2 0.4
National 19.6 3.7 -5.8 -0.2 -2.2 15.1
Regional Impacts
(USD/per capita/yr)
Climate Scenario
Region
1.5C 2.5C 5.0C
15%P 7%P 0%P
Northeast 28 52 19
Midwest 84 84 36
N Plains 539 359 75
Northwest 410 80 -369
Southeast 91 6 -122
S. Plains 129 5 -266
Southwest 80 11 -134
National 97 52 -56