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Agency Responsibilities: Within the USGCRP, five agencies contribute to advancing the state of global modeling. The GAO report includes information developed with the USGCRP agencies describing their areas of emphasis in modeling climate change. Examples of areas of emphasis are:

1. Department of Energy: DOE's Atmospheric Model Intercomparison Project is working with the various national and international modeling groups on simulation of the period since 1978. Other programs focus on use of massively parallel computers, the global carbon cycle, and the effects of carbon dioxide on climate.

2. Department of Commerce: In addition to significant modeling support for seasonal to interannual climate fluctuations, NOAA supports ocean-atmosphere modeling to simulate climate fluctuations from earlier this century and natural variations over longer periods, climate change due to greenhouse gases, and comparison of observed climate change to model simulations.

3. National Science Foundation: NSF supports research to simulate climates of the past, present, and future and more generally of the dynamics of the system. NSF also support supercomputer facilities used for multi-agency activities.

4. National Aeronautics and Space Administration: NASA focuses its modeling most intensely on assembling satellite data for use in developing and evaluating model behavior and in understanding the climate's response to various types of natural and human-induced forcings.

5. Environmental Protection Agency: EPA emphasizes the inclusion of ecosystems and biogeochemistry in model simulations.

Together, these agencies support an interlocking and complementary effort that provides both some focusing of activities and the diversity needed to ensure that important shortcomings are not overlooked. Attached to this testimony is a statement prepared by the coordination office of the USGCRP earlier this year that describes agency programs in global climate change modeling in greater detail.

IPCC Assessments for Summarizing and Evaluating Model Results: While there are three main and a number of more specialized modeling groups in the U.S. and several other major groups throughout the world carrying out simulations of the potential effects of long-term changes in the climate, the assimilation and evaluation of input for decision makers is carried out through an assessment process. In the area of climate change, the U.S. participates strongly in the periodic assessments of the Intergovernmental Panel on Climate Change (IPCC). In these efforts, hundreds of scientists from throughout the world participate in the submission and evaluation of materials. Their initial draft chapters are then further reviewed by scientific experts, representatives of nongovernmental groups, and by government scientists and agencies. The SGCR managed the U.S. Government review process this year, and we can assure that it was both intensive and broadly inclusive. As one example of how broad it was, the U.S. Government made the draft report generally available through a Federal Register notice, a process which allowed an extensive range of people to participate.

An interesting result of the IPCC process this year was the recognition that the level of confidence in the projections of climate change is increasing, because we have become better able to understand, with reasonable confidence, why the climate has been changing over the past hundred years.

USGCRP Modeling Forum: In addition to the IPCC process, the USGCRP organizes other ways of evaluating the general character of the results. A year ago, for example, the USGCRP convened an informal Modeling Forum that included leading modeling scientists as well as skeptics and users of model results. We asked them to provide a balanced perspective on the certainty that could be associated with important aspects of the model results. We did not expect everyone to agree with each results, but we wanted to have a summarization of results in a way that qualified experts might split roughly between those who thought a weaker or stronger statement could be made. One purpose of this forum was to help the GAO better understand what was limiting scientific understanding and where it stood; another purpose was to provide a baseline against

which we expect, over approximately a five year time frame, to determine if our research program is helping to improve understanding and the confidence to be placed in model projections. A copy of this report is included with my testimony.

National Research Council Review. In addition to the normal peerreview process for evaluating individual research proposals and the IPCC and related processes for assembling and assessing the model results, the USGCRP sponsors the Climate Research Committee (CRC) of the National Research Council. This committee holds several meetings a year on various issues relating to climate change research and modeling, and offers a number of comments and suggestions for research. The CRC also assists the USGCRP by serving as the U.S. national scientific committee that interfaces with research and modeling activities of the World Climate Research Programme. The work of the CRC has been coordinated with other units of the National Research Council, including the special review panels that evaluated the USGCRP during the last summer, in part at the request of Representative Walker. We thus believe we have a quite broad and diversified set of mechanisms for ensuring that we have the highest-possible quality focus on this critical issue.

Summary: Despite the wide range of research and the extensive reviews, many aspects of the behavior of the Earth system still are not fully understood. As such, there is, quite appropriately, a continuing and active set of exchanges of critiques and responses followed by further research and advances. There are times when these spill out of the traditional scientific channels and receive wider attention. The attention given to a few of these controversies has obscured the very active and normal scientific exchange of views. Within the USGCRP, we work hard to make sure that pathways are open, that dialog takes place, and that questions and uncertainties are addressed. We are currently able to fund only a relatively small percentage of the generally high-quality proposals, so many important scientific questions require further exploration. Fortunately, the complementary nature of the federal agency efforts, and smaller efforts that we encourage by other sponsors (e.g., the Electric Power Research Institute) provide a very diverse and challenging set of perspectives that we believe ensures the integrity of the science.

In order to achieve our goal of improving long-term assessment and predictive capabilities based on knowledge of the integrated components of the Earth system, we plan to continue to address the uncertainties in today's models. In doing so, we expect to provide the nation with benefits in the form of improved understanding that will benefit agriculture, water resources, and other forms of economic activity just as we have seen the benefits of recent investments made in improved short-term weather as well as seasonal and interannual forecasting capabilities.

Thank you very much for this opportunity to participate in this hearing, and I would welcome questions from the subcommittee.


"Our Changing Planet," A report by the SGCR submitted as a supplement to the President's FY 1996 budget.

Statement on "U.S. Global Change Research Program Agency Programs in Global Climate Change Modeling" prepared by Michael MacCracken, April 1995.

Letter from Robert Corell to Peter Guerrero of GAO dated May 22, 1995, and attachment.

Statement on “Earth System Modeling Activities in the United States” prepared by Michael MacCracken, February 1995.

USGCRP Report on “Forum on Global Change Modeling" (USGCRP-95-02).

U.S. Global Change Research Program
Agency Programs in Global Climate Change Modeling'

Prepared by
Michael C. MacCracken, Director
Coordination Office of the USGCRP
April 1995 (updated from Feb. 1995)


Use of models that represent the Earth system to make projections of future environmental conditions necessarily rests on the foundation of understanding how the Earth system functions now and has functioned in the past. Development of this understanding requires a broad-based research program that includes observations taken at the surface and from space, the assembly of global data sets for driving and testing of model simulations, analysis of results from focused studies designed to improve understanding of important processes and influences, scenarios of the future level and type of socio-economic activities, estimation of the interactions among system components, inventories and records of human-induced factors that force change, and more. These needs are all in addition to the modeling activity itself, which requires: development of quantitatative formulations (i.e., parameterizations) for representing physical, chemical, and biological processes that can be included in models, comparison and testing of the models with observations of current and past climatic behavior, analysis of

This brief note has been prepared at the request of the General Accounting Office to describe agency modeling programs that focus on the issue of global climate change. In particular, the GAO request is interested in activities relating to global three-dimensional modeling in areas such as: a. testing, verifying, and/or applying global models of the atmosphere,

oceans, and/or land surface (including global chemistry related to greenhouse forcing and/or vegetation models) and whose focus is on simulation of global climate, climate variability, and climate change on time scales of decades to centuries relating to changes in the concentrations and chemistry of greenhouse gases and aerosols and/or

land surface change due to human activities; b. simulation of the baseline global climate system (including vegetation)

to which perturbation studies are being compared; c. global simulation of paleoclimates where the purpose is to understand factors that can help in understanding and identifying climate change

due to human activities; and
d. global verification and model intercomparison studies, including

diagnosis of results from global models and associated comparison
with observations.

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