fundamental research to research that expands the knowledge base upon which the Nation and world may be able to effectively respond or adapt. It is important to note at this point, however, that the USGCRP does not include research on new energy technologies, nor does it include support for research underpinning specific response policies, such as the Climate Change Action Plan. The USGCRP is designed to improve the base of fundamental understanding about what is happening and about what scientific research indicates might happen in the future, not to support the implementation of particular policies.

Global Change Research Objectives: Because global change is so broadly defined, the SGCR has developed a program that places special emphasis on improving the information base concerning five specific objectives:

1. Seasonal to Interannual Climate Fluctuations and Related Events: To predict climate fluctuations and environmental interactions over seasons to years, particularly the irregular occurrence of the El Nino warmings that affect the tropical Pacific Ocean and thereby the weather in the tropics and southern and western United States, and elsewhere on the planet;

2. Climate Change Over the Next Few Decades: To understand and project changes in climate and the environment over decades to centuries, especially the climatic changes (from warming and cooling effects) and environmental consequences expected from increasing concentrations of greenhouse gases, aerosols, other human influences, and natural factors that control climate variability,

3. Stratospheric Ozone Depletion and Increased UV Radiation: To predict depletion of stratospheric ozone, resulting increases in UVradiation, and changes in tropospheric (lower atmosphere) chemistry that affect, among other aspects, the ability of the atmosphere to cleanse itself of pollutants;

4. Changes in Land Cover and In Terrestrial and Marine Ecosystems: To monitor and understand changes in land cover and in terrestrial and marine ecosystems, including changes in land use, deforestation, and desertification; and

5. Earth System Science: To sustain exploratory research that increases understanding of the complex behavior of the total Earth system, identifying potential surprises and ensuring that all factors are being considered.

This hearing is concerned primarily with research on the second of the five objectives, although it relates in some way to all five.

Global Change Research Streams: To pursue these intercoupled objectives, the USGCRP supports research of various types that contributes in varying degrees to all of these efforts. The research is generally subdivided into six research streams:

1. Observations of the Global System: The major fraction of funding for observations of the global system is designated for NASA's Earth Observing System of satellites. Also relevant are programs for surface-based observing of UV radiation, ecosystems, and critical facets of the Earth system. Interagency and international efforts are underway to move toward an integrated global observing system.

2. Documentation and Data Management: USGCRP agencies have organized the Global Change Data and Information System (GCDIS) to make available their many data sets for research and analysis. NASA's EOSDIS is a major component of GCDIS, but all agencies are actively participating. Agency implementation plans are now going through the approval process.

3. Field Programs and Process Studies: Together with nations around the world and within the U.S., internationally coordinated research programs' are underway to understand how such processes as cloud

'There are three major intemationally coordinated research programs, coordinating and integrating the research efforts of literally tens of thousands of scientists, research specialists, and research associates, and virtually all the nations of the world. The programs are: (i) The World Climate Research Program (WCRP), (ii) The International Geosphere-Biosphere Programme (IGBP), and (iii) The Human Dimensions of Global Environmental Change Programme (HDP). These Programs are all sponsored by the International Council of Scientific Unions (ICSU), the international academy of science. Further, the WCRP is co-sponsored by the World Meteorological Organization (WMO) and the Intergovemmental Oceanographic Commission (IOC). Finally, the HDP is co-sponsored by the International Social Sciences Council (ISSC).

radiation feedback, ocean circulation, the hydrologic cycle, atmospheric chemistry, and many other physical, chemical, and biogeochemical processes influence the functioning of the global Earth system.

4. Modeling the Past, Present, and Future Behavior of the Global System: Putting together all of the information on how the system functions and how processes interact can only be done using quantitative simulation models. The USGCRP supports a range of efforts to look at different time scales, different aspects of global change, and different components of the global system.

5. Estimating the Consequences of Global Change: Change is a natural feature of our world. The important issue is what the consequences of the change will be for societally important systems, such as agriculture, water resources, forests and other ecosystems, health, commerce, and industry.

6. Methods for Analyzing the Implications and for Assisting Decision Makers: To support decision making in private and public settings, research is conducted that develops and tests tools that can provide an integrated perspective of change and its consequences.

Global Change Research Budget: For this hearing, you have asked us to discuss primarily the third and fourth streams of research. These are very important parts of the overall effort, but you can see that they are by no means our entire program. To provide a funding perspective, in FY 1995, agency research that focused directly on USGCRP objectives totaled about $1.8 billion. Of this amount, approximately 60% was devoted to observations and data management, about 30% to process studies, about 4% to global change modeling (with 3% supporting long-term climate modeling), and the other 6% divided between studies of consequences and the development and testing of tools for analyzing implications and decision making. The FY 1996 program of research and requested budget is described in detail in "Our Changing Planet", a document that is submitted to the Congress as a supplement to the President's

FY 1996 Budget A copy of "Our Changing Planet" for FY 1996 is attached to this testimony.

Thus, while modeling and impact studies garner significant attention, they are a relatively modest component of the overall budget. They are particularly important, however, because they are the aspects of the program where the many other parts are tied together in ways that become meaningful for analysts and decision makers.

Modeling Climate Change

Why Modeling is Vital: Attempting to understand the behavior of the Earth system and to predict and project its behavior, including its climate and the consequences of climate change, is one of the most challenging scientific problems. Spatial scales range from local to global, time scales from minutes to millennia, and processes include physical, chemical, and biological. Without the aid of computer-based modeling systems, one cannot keep track of the many important and complex interactions that govern the behavior of the planet. It is not possible to construct even a realistic physical model of the Earth system in a laboratory and to experiment with it much less a full chemical and biological model. Furthermore, it is not possible to apply in a straightforward way what has happened in the past as a means for predicting the future because of the uniqueness of human influences that now appear to be intermixed with natural processes. While all of these approaches can help to improve understanding, the only viable approach is the use of comprehensive, computer-based, models of the global system that incorporate as much knowledge as is possible of how the system works. Such models have come to be called global climate models, Earth system models, or general circulation models (GCMs), depending to some extent on what set of processes they include and how they are used. To a great extent, they represent the integrated understanding of the dynamics of the Earth system. Attached to this written testimony is a report on Earth

*The USGCRP has submitted annually an issue of "Our Changing Planet", as a supplement to the President's budget submission to the Congress. These program and budget documents have accompanied every budget submission since FY 1990.

System Modeling Activities in the United States that was prepared by the coordination office of the USGCRP earlier this year.

Model Structure: Earth system models consist of reasonably comprehensive, but still limited, sets of mathematical equations that represent the state of scientific understanding of winds and air pressure, ocean currents and eddies, temperature and salinity, water vapor and clouds, solar and infrared radiation, precipitation and evaporation, snow cover and runoff, atmospheric chemistry, biogeochemical cycles, ecological processes, and many other important factors. The models are global, including treatment of the oceans, the atmosphere, the land surface, and sea ice and snow cover. Although the models have grids the size of states like Wyoming and Utah, they are able to resolve conditions only on scales of roughly one-third to one-half of the continental U.S. and over times of decades to a century. To do better requires finer spatial resolution and improved representations of processes, both of which require increased computational capabilities. While the DOE's Computer Hardware, Advanced Mathematics, and Model Physics (CHAMMP) program is helping all agencies take advantage of the most advanced parallel computers and enhanced supercomputer capabilities at the National Center for Atmospheric Research (NCAR) are facilitating the operation of larger, more complex models, tradeoffs still must be made as researchers work to most effectively address particular aspects of the problem. The GAO report entitled "Global Warming: Limitations of General Circulation Models and Costs of Modeling Efforts" identifies a number of these trade-offs, all of which are being worked on as indicated in the SGCR response letter that was included in their report. Attached to this testimony is a copy of the letter to GAO that provides some perspective on the strengths of the models that do exist and a summary of how the USGCRP is addressing their limitations.

Testing Models: In spite of their limitations, these models are quite capable of representing many aspects of Earth system behavior. Developing a sense of how much confidence to place in these models is an important, but very challenging, aspect of the USGCRP research effort. How processes such as infrared radiation are represented in the models is being tested both in the laboratory and in field