EXECUTIVE SUMMARY

• Computer models successfully predicted the onset of the 1997-98 El Niño event with sufficient lead-time so that actions could be taken to mimimize damage from predicted flooding rains.
• Studies of past variations in the climate indicate that global average temperatures by the end of the next century could be warmer than any that have occurred on the Earth for several million years.
• Research results have strengthened the evidence that the phaseout of chlorofluorocarbons and other ozone-depleting compounds will significantly reduce levels of chlorine in the stratosphere.
• Observation and monitoring from space of changing land cover are providing an important foundation for efforts to make land use more sustainable.

These and other findings about changes in the Earth system are leading to a deeper appreciation of how human activities influence and are influenced by global change.

Much of the research supported by the USGCRP has emphasized global phenomena, and this research will continue to be extended and deepened. The USGCRP also has been actively building links between research and society's application of new knowledge in particular regions and sectors. For example, an important USGCRP priority is to improve capabilities to project climate change and other aspects of global change on a regional basis, as well as initiating a National Assessment of the ecological, economic, and social consequences of climate change in the context of other stresses. Research supported by the USGCRP has been central to the development of the international scientific assessments that underlie the United Nations Framework Convention on Climate Change (FCCC) and the Montreal Protocol on Substances that Deplete the Ozone Layer. Continued research will be needed to meet the challenges posed by international negotiations and agreements.

Four Key Global Change Issues

1. Seasonal to Interannual Climate Variability --The USGCRP seeks to obtain the understanding and skills needed to forecast short-term climate fluctuations and to use these predictions in social and economic planning and development in the United States and abroad.
2. Climate Change Over Decades to Centuries --The USGCRP seeks to understand, predict, and assess changes in the climate that will result from the influences of projected changes in population, energy use, land cover, and other natural and human-induced factors; to understand, predict, and assess the consequences of climate change for society and the environment; and to provide the scientific information society needs to address these changes.
3. Changes in Ozone, Ultraviolet Radiation, and Atmospheric Chemistry --The USGCRP seeks to understand and characterize chemical changes in the global atmosphere and their consequences for human well-being.
4. Changes in Land Cover and in Terrestrial and Aquatic Ecosystems --The USGCRP seeks to understand, predict, and assess the causes, magnitude, and consequences of changes in land cover and in terrestrial and aquatic ecosystems, and to strengthen the scientific basis for sustainable environmental and natural resource practices.

In pursuing these goals, the USGCRP is seeking to observe and document changes in the Earth system, understand why changes are occurring, improve predictions of future changes, analyze the environmental, economic, and social implications of change, and support scientifically based assessments of global environmental change issues.

Integrative Activities

• To ensure a long-term, high-quality record of the state of the Earth system, its natural variability, and changes that are occurring.
• To provide all users ready and affordable access to the full spectrum of global change data, products, and information in useful forms.
• To gain an understanding of the interactions among the physical, chemical, geological, biological, and solar processes that determine the functioning of the Earth system and its trends and fluctuations on global and regional scales.
• To identify, understand, and analyze how human activities contribute to changes in natural systems, how the consequences of natural and human-induced change affect the health and well-being of humans and their institutions, and how humans could respond to problems associated with environmental change.
• To support and assist the program and its participating scientists and their interactions with related international research, observing, and assessment activities.
• To increase public awareness of the Earth system and how it is changing and to promote education on a wide range of global change issues.

National Assessment of the Consequences of Climate Change

A series of 20 workshops is being held to identify the distinctive regional characteristics and potential consequences of climate change and variability. The next phase will include a set of regional assessments, a set of sectoral assessments, and a national synthesis that draws together the regional and sectoral assessments in a summary for policymakers. A National Assessment report will be issued in 1999.

Summary of Key USGCRP Accomplishments in 1997 National Assessment--A national assessment of the consequences of climate change for the United States was begun during 1997. Eight regional workshops and the U.S. Climate Forum, a major national workshop with more than 400 participants, examined the likely consequences of climate change for U.S. regions and ecological and economic sectors. El Niño Southern Oscillation--There was continued improvement in the accuracy and lead times of predictions of seasonal climate fluctuations associated with the El Niño Southern Oscillation. Several forecasting activities successfully predicted the onset of the 1997-98 El Niño event early enough to support flood mitigation actions. Climate Change--A new 300-site survey of borehole temperatures on four continents produced a detailed record of the climate of the last 5 centuries, confirming that the Earth is warming and that the rate of warming has been accelerating since 1900. Global Temperature Record--Based on observations of global average surface temperature, scientists from the NOAA National Climatic Data Center found that 1997 was the warmest year on record since measurements began, continuing the recent pattern in which the 1980s and 1990s have produced 12 of the 13 warmest years on record. 20th Century U.S. Rainfall--Another NOAA analysis showed an average 5 to 10 percent increase in the overall amount of U.S. rainfall in the last 100 years. The frequency of heavy downpours, in which more than 2 inches of rain falls in a day, has increased by about 20 percent. Such events can lead to flooding, soil erosion, and even loss of life. Global CO2 Emissions--The DOE Carbon Dioxide Information and Analysis Center (CDIAC) released data showing that global emissions of CO2 grew by about 5 percent between 1992 and 1995, and have reached the highest level ever recorded. Stratospheric Ozone--Observations in the stratosphere show a flattening out of the growth curve of hydrogen fluoride, which at that altitude is a very good indicator of the total amount of industrially produced halogens (especially fluorine and chlorine) in the atmosphere. In concert with previous findings of decreasing halogen levels in the troposphere, these results prove that regulation under the Montreal Protocol on Substances that Deplete the Ozone Layer is affecting stratospheric composition. Arctic Ozone Depletion--Unusually low values of total ozone observed over the Arctic in the spring of 1997 demonstrate that, for appropriate meteorological conditions, appreciable chemically induced ozone depletion resulting from human activities can occur in the Arctic as well as the Antarctic. Mapping Global Land Cover--Development of the first global synthesis of information on land cover at a spatial resolution of 1 km (about 0.6 miles) was completed. These data are helping improve understanding of land cover, ocean productivity, and the cycling of carbon through the Earth system, thus contributing to better predictions of climate change on national and global scales. Tropical Rainfall Measuring Mission (TRMM)--The TRMM satellite, a joint NASA-Japanese project, was successfully launched in November 1997, and is providing rainfall observations that are improving our understanding of the global hydrological cycle and its role in climate change and variability. SeaWiFS--Ocean productivity images from the SeaWiFS instrument aboard the SeaStar satellite, launched in 1997 as part of an innovative public-private partnership, are playing a major role in understanding the behavior and consequences of the ongoing El Niño and in other global change research. Total Ozone Mapping Spectrometer (TOMS)--Following the failure of the Japanese ADEOS spacecraft in mid-1997, NASA successfully changed the orbit of another satellite to allow resumption of near-global daily mapping of ozone by TOMS, as well as concentrations of stratospheric sulfur dioxide produced from large volcanic eruptions. Atmospheric Radiation Measurements (ARM)--The third ARM site, on the North Slope of Alaska, began operation in 1997. The ARM program focuses on the effects of clouds on the Earth's radiative energy balance, a major source of uncertainty in climate models. Intergovernmental Panel on Climate Change (IPCC)--USGCRP research continued to play a leading role in the IPCC during 1997, and provided important contributions to the IPCC Special Report on Regional Impacts of Climate Change: An Assessment of Vulnerability  and to several IPCC Technical Papers on other key issues. A U.S. citizen, Robert T. Watson, was elected overall Chair of the IPCC, replacing Bert Bolin of Sweden, and James McCarthy of Harvard University was elected Co-Chair of IPCC Working Group II, which will assess impacts and adaptation options.

Summary of USGCRP Goals and Expected Performance for FY99 National Climate Change Assessment The first U.S. national assessment of the consequences and implications of climate change and variability for the United States will near completion. Reports describing regional and sectoral analyses will emerge from the review phase by late FY99 and the review draft of the national synthesis report will be near completion. Seasonal to Interannual Climate Variability Observations, analyses, and modeling studies of the El Niño Southern Oscillation (ENSO) will focus on understanding the cause- and-effect relationships between midlatitude and tropical variability on decadal time scales, which is expected to contribute to improving ENSO predictability. Observations, analyses, and modeling studies will focus on documenting and understanding decadal variability centered on the Atlantic Ocean, such as the North Atlantic Oscillation (NAO), which is a critical determinant of climate over much of Europe and the East Coast of North America, with the goal of eventually predicting variations in the NAO. Observations of climate variability will be expanded in the Atlantic Ocean, with a pilot system of networks designed to measure the key parameters of the ocean and atmosphere relevant to climate prediction. Experiences documented during the 1997-1998 ENSO event will be used to study how social and economic systems are influenced by short-term climate fluctuations and how human behavior can be (or may not be) affected by information about such fluctuations. Pilot applications projects will develop methodologies for society to utilize climate forecast information to reduce socioeconomic disruption. Climate Change Over Decades to Centuries USGCRP scientists will actively participate in the preparation of the Third Assessment Report (TAR) of the Intergovernmental Panel on Climate Change (IPCC), which is scheduled for completion in late 2000 or early 2001. Several new and improved data sets, which will include model simulations, will be made available for the IPCC assessment and the U.S. National Assessment. Both the Joint Global Ocean Flux Study (JGOFS) and the World Ocean Circulation Experiment (WOCE) will be well into a phase of analysis, interpretation, modeling, and synthesis. Preliminary assessments of both the Pacific and Indian Oceans will be available, as will the first interdisciplinary analysis of seasonal carbon cycling and CO2 drawdown in the Ross Sea and in the region of the Antarctic Polar Front. The first phase of a study of the climate of the 20th century and the climate of the future, as simulated by the community Climate System Model, will be completed. The simulations will include changes due to greenhouse gases, aerosols, and solar variability and will enable a critical evaluation of the predictive capability of climate models. Field experiments and focused model simulations will be initiated to study the effects of tropospheric and stratospheric aerosols on global and regional radiative balances and climate. The observational phase and initial analyses of the data will be completed in the Indian Ocean Experiment (INDOEX), which will examine and help quantify the influence of natural and human-produced aerosols on future climate change. Model simulations and observations needed to increase confidence in the detection and attribution of human-induced climate change will be prepared using updated and more comprehensive data and improved detection procedures. Simulation studies will be conducted of various greenhouse-gas atmospheric stabilization trajectories using improved coupled atmosphere-ocean climate models. Changes in Ozone, UV Radiation, and Atmospheric Chemistry The IPCC Special Report on Aviation and the Global Atmosphere  will be published, with USGCRP scientists having made important contributions. This will be the authoritative assessment by the international scientific and technical communities of the impacts of aviation on the atmosphere, including ozone layer depletion and climate change. The Scientific Assessment of the Ozone Layer: 1998,  a periodic international scientific assessment prepared on behalf of the Conference of the Parties to the Montreal Protocol, will be published, with USGCRP scientists serving as co-chair and lead authors. The focus of the assessment will be on management of the recovery of the ozone layer over the coming decades and on the relationship of ozone depletion to other global environmental issues, such as climate change. The Pacific Exploratory Mission (PEM)-Tropics B, an airborne field campaign, will be conducted during February-April 1999, to document air quality baseline data over the tropical Pacific Ocean. These data will be essential to quantifying expected future impacts on the tropical Pacific atmosphere from biomass burning and emissions from rapid industrial development in Asia. A peer-reviewed report describing the integrated, multi-agency, national UV monitoring program will be published. Changes in Land Cover and in Ecosystems The Landsat-7 satellite will provide the United States for the first time with a global data set updated on a seasonal basis (3-4 times annually) for analysis of changes in land cover. These data will be critical for documenting land-cover change due to both natural disturbances and human influences. The Earth Observing System (EOS) AM-1 satellite will provide near- daily global measurements of indicators of photosynthetic processes, allowing determination of carbon uptake by the terrestrial biosphere. Interactions between terrestrial surfaces and the atmosphere will be better defined in terms of the transfer of energy, water vapor, and especially carbon dioxide, as the AmeriFlux and Grassland CO2 flux networks complete 2-3 years of measurements in forests and rangelands, providing critical information on the global carbon balance and providing modelers with better data sets. Observing and Monitoring Global Change Scheduled for launch in 1998, the EOS AM-1 satellite will carry five state-of-the art instruments to observe the continents, oceans, and atmosphere and their interactions. EOS AM-1 will measure the radiative properties of the atmosphere, enabling estimates of the heating and cooling of the Earth and atmosphere. Scheduled for launch in 1998, Landsat-7 will add to the record of more than 25 years of continuous data on the condition of the Earth's terrestrial surface. Scheduled for launch in 1998, QuikSCAT, designed to replace the failed Japanese ADEOS spacecraft, will measure winds at the ocean surface, the key to the next major improvement in near-term weather forecasting. Surface levels of chlorine- and bromine-containing chemical compounds addressed under the Montreal Protocol will be measured, to quantify the decreasing concentrations of regulated compounds. Global Change Data, Products, and Information Services The Global Change Data and Information System (GCDIS) will be expanded to meet the special data and information access needs of the national assessment of the conseqeunces and implications of climate change and variability for the United States. The application of the USGCRP "full and open" data access policy will be broadened to facilitate the incorporation of non-Federal data sources into national assessments of global change. The USGCRP will publish a list of citations, including authors, pertaining to global change-related data sets produced in FY99. The coordination of GCDIS with other data and information access system components of programs will be expanded to include the Integrated Global Observing Strategy (IGOS) and the Inter- American Biological Information Network (IABIN).

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