Introduction

The U.S. Global Change Research Program and its international counterparts were begun to enhance understanding of the global environment and to predict its future evolution. Such collaborative work has long been a hallmark of the Earth and life sciences, in which investigations characteristically transcend the boundaries of classical scientific disciplines and individual nations. Thus, a long history of increasingly ambitious and increasingly integrated scientific programs may be traced, from the polar programs of the late nineteenth century through the International Geophysical Year of 1958 to the Global Atmospheric Research Program, the International Decade of Ocean Exploration, and the International Biology Program of the 1970s.

By the 1980s, a growing body of research, coupled with new views of the Earth from space, reinforced science's vision of our planet as a tightly interconnected and constantly changing system. Public awareness of the links between the current and future state of the global environment and human activities increased during this same period. In combination, scientific insights, technological opportunities, and societal concerns led to proposals for ambitious new scientific programs to advance our understanding of the Earth system.

For these reasons, President Reagan in January of 1989 announced the United States Global Change Research Program (USGCRP) as a presidential initiative for fiscal year 1990 and the federal government's effort to establish the scientific basis for national and international assessments of changes, both natural and human induced, in the Earth system. President Bush reaffirmed the initiative, and congress codified the program through passage of the Global Change Research Act of 1990. President Clinton has continued to support the USGCRP as a priority in the national science and technology agenda. Parallel international programs already existed or were created dealing with the climate system, geosphere- biosphere issues, and interactions between the environment and human activity.

The USGCRP has grown programmatically from diverse roots in existing programs and planned activities within several federal agencies and reflects the evolution of closely related international programs such as the World Climate Research Program (WCRP), the International Geosphere-Biosphere Program (IGBP), and the Human Dimensions of Global Environmental Change Program (HDP).

In the early 1980s, the National Aeronautics and Space Administration (NASA) advanced a comprehensive new program: Mission to Planet Earth (MTPE). The centerpiece of the new program was an ambitious series of new satellites called the Earth Observing System (EOS). The satellite and the research and analysis programs of NASA's MTPE are key contributions to the USGCRP. Similarly, the early 1980s saw the emergence of the National Science Foundation's Global Geosciences initiative, and in 1989 the National Oceanic and Atmospheric Administration (NOAA) also began a Climate and Global Change Program focusing on related scientific objectives. With the formal initiation of the USGCRP as a presidential initiative in fiscal year 1990, contributions from the Department of Interior's U.S. Geological Survey were incorporated into the program.

Today, the USGCRP reflects the programmatic contributions of 11 federal agencies. Under the auspices of the National Science and Technology Council, the Subcommittee on Global Change Research of the Committee on Environment and Natural Resources provides the principal federal mechanism for integrating these individual agency efforts into a coordinated program. From the perspective of the participating agencies, the USGCRP fulfills three related objectives:

  1. advancing scientific understanding of the global environment;
  2. meeting agency-specific missions and responsibilities; and
  3. providing reliable scientific information to support national and international decision making.

In the decade since the planning for the USGCRP began, much has been learned regarding the forces producing global change and the complexity of the connections between those forces and responses in the Earth system. We can point to many achievements, some scientific and some having significant economic value. A great deal of extremely high-quality science that is recognized worldwide for its excellence and leadership has resulted from the USGCRP. We have gained a greater appreciation of the need to link physical and natural scientific studies with those addressing the social sciences and economics. Thus, although the motivation for the USGCRP retains its original force and the scientific foundations remain strong, our experience suggests the need for improved management and broader participation and perspectives.

GUIDING PRINCIPLES

As the foundation for the recommendations that follow in this report, the Committee on Global Change Research:

Building on this foundation, the Committee on Global Change Research has enunciated the following set of fundamental guiding principles that should guide the development and implementation of the U.S. Global Change Research Program in the future:

SCIENTIFIC DIRECTIONS

The activities of the U.S. Global Change Research Program are aimed at well-focused scientific issues of global change. These issues reflect the continuing evolution of global change research toward increasing levels of intellectual and programmatic integration and represent the appropriate principal foci for the USGCRP. The questions identified within each of these four scientific areas are intended to illustrate the lines of scientific inquiry that characterize the program's efforts. In the areas of seasonal to interannual climate and atmospheric chemistry, these questions reflect a highly refined set of specific priorities characteristic of the level of scientific and programmatic maturity achieved by USGCRP programs in those areas. The more general questions associated with climate change on the time scale of decades and with large-scale ecosystem change are characteristic of the somewhat more exploratory nature of research in these fields.

Seasonal to Interannual Climate Fluctuations

How does the El Niñ o/Southern Oscillation (ENSO) cycle in the tropical Pacific contribute to climate anomalies and related extreme events such as droughts, floods, and severe storms, and what other processes are involved? What are the controlling processes relevant to climate on seasonal to interannual time scales and regional to global spatial scales? Can we develop predictive models that include these processes? How can we predict seasonal to interannual climate fluctuations and associated extreme events, and how do we simulate the potential economic impacts on agricultural, water resource, and other socioeconomic systems?

Changes in the Chemistry of the Atmosphere

What are the trends and patterns of change in ozone concentrations in the stratosphere and upper troposphere, and the related trends and patterns of ultraviolet radiation at the Earth's surface and climate perturbations? What are the trends of tropospheric ozone, aerosols, and pollutants in the lower atmosphere? Can we model the physical and chemical processes in the atmosphere to permit prediction of changes in ozone, aerosols, pollutants, and related climate effects? Can we assess the implications of changing concentrations of ozone and other chemical species on human health and natural ecosystems?

Changes in Terrestrial and Marine Ecosystems

What are the trends and the geographic and temporal patterns of change in global land cover? What are the processes, both natural and human induced, that lead to changes in land cover, land use, and marine productivity, including such processes as deforestation, desertification, and loss of global resources, including biological diversity and productivity? How do managed and natural ecosystems interact with the atmosphere in the exchange of energy, water, carbon dioxide (CO2) and trace gases, and how do those exchanges affect global and regional climates and water resources? What are the processes that control the exchange of biogenic trace gases between terrestrial ecosystems and the atmosphere? What is the distribution of sources and sinks for CO2 and how is it changing? What processes govern the ocean's uptake of atmospheric carbon dioxide? What governs the variability of phytoplankton communities that form the base of the oceanic food chain? What are the links with higher species--fish, invertebrates, and mammals?

Changes in Climate over the Next Few Decades

What are the trends and patterns of change in the Earth's climate system, including the atmosphere, oceans, glaciers, sea ice, and the biosphere? How have these patterns varied in the past? What is the nature of the processes relevant to the dynamics of climate, including both internal factors such as water vapor, clouds, and heat transfer by the atmosphere and oceans, and external factors such as solar variability and volcanic activity? Can we develop predictive models of regional to global climate change over time scales from a decade to a century? What is the vulnerability of Earth systems, including economies, human health, and ecological systems, to climate fluctuations and changes on these time scales?

PROGRAM MANAGEMENT

The experience of the past decade or so has provided valuable insights into the management of large-scale Earth science projects. Those elements of the USGCRP that have worked well (e.g., the WCRP Tropical Ocean-Global Atmosphere (TOGA) Program and research on stratospheric ozone) have been focused on clearly defined Earth system problems and have been characterized by close collaboration within and among the national and international scientific communities and federal funding agencies on both development and the implementation. When this collaborative approach works well, the scientific community and the responsible parties in the federal government (both executive and legislative branches) share a scientific vision and a commitment to the programmatic discipline necessary to implement that vision:

The specific findings and recommendations that follow provide guidance toward taking the next steps in the evolution of the USGCRP and NASA's MTPE/EOS program.