Global Change Environmental Science Issues

Enhancing the USGCRP Focus on Priority Issues

In its 1995 review of the USGCRP, the National Research Council recommended that, in order to be most effective, the USGCRP "...should focus on priority issues in four mature areas of Earth system science that are of great scientific and practical importance."

A USGCRP internal review had suggested similar steps be taken, to more closely integrate scientific research with the objectives and needs of societal decision making. The FY96 edition of Our Changing Planet includes a description of the scientific basis for these environmental science issues and a summary of key recent findings in each area.

As a consequence of these external and internal reviews, the USGCRP is moving aggressively to focus research efforts on the four interrelated environmental science issue areas that were identified:

The remainder of Chapter 2 provides an overview of research and program activities and directions for each of these key issues. For additional information on recent progress in each of these environmental areas, the Our Changing Planet for last year (reporting on the FY96 budget proposal) provided an introductory discussion of each of these issues and reported on recent research accomplishments. Additional detail on planning in each of these areas for the next 5 to 10 years will be included in the full National Global Change Research Plan, which is being prepared by interagency teams for review by the NRC before submission to Congress pursuant to the Global Change Research Act of 1990.

Seasonal to Interannual Climate Variability

Understanding Year-to-Year Climate Fluctuations:
Forecasts and Applications

Climatic records and human experience demonstrate that the Earth's climate is a naturally dynamic system. Variations in climate occur on time scales of seasons to years, and decades to centuries. These natural fluctuations in the patterns and amounts of precipitation, temperature, and other climatic measures significantly influence agricultural productivity and economies around the world.

Meteorologists currently track and forecast the weather - that is, the state of the atmosphere at a given time and place. These forecasts provide the public with useful information about expected near-term precipitation, temperature, and wind conditions. Until recently, meteorological forecasting skill was limited to predicting weather changes over the next several days. Now, scientists are gaining the skill to forecast prevailing precipitation and temperature conditions in particular regions over periods of time from a season out to even a year.

Scientists are making exciting breakthroughs in understanding climate fluctuations that occur on time scales of seasons to years. These breakthroughs could ultimately revolutionize the relationship between human activities and the natural environment. The USGCRP plays a leading role in an ongoing international endeavor to develop and enhance prediction capabilities and to apply experimental forecasts to real problems of the management of increasingly scarce water resources, agricultural production, forests and other managed ecosystems, emerging and re-emerging vector-borne diseases (carried by insects, rodents, and other organisms), and coastal fisheries.

Variations in rainfall and temperature patterns that occur on time scales of seasons to years can lead to extreme climatic conditions, such as droughts and floods. Extended periods of drought and heat can increase the susceptibility of urban settlements and forest and rangelands to fire, disrupt food production and water supplies, and, in developing regions, occasionally lead to massive human migrations. Prolonged and excessive periods of precipitation can cause flooding, delay planting, contaminate water resources, and temporarily disrupt patterns of production and trade.

Extreme weather events, such as the recent flooding in Oregon, Washington, Montana, and Idaho, the multi-year drought in California in the late 1980s and early 1990s, and the very snowy winter of 1996 in the eastern United States are not necessarily due to random chance, as was once believed. There is tantalizing evidence that many of these extreme events are linked to a natural phenomenon known as the El Niño/Southern Oscillation. When an El Niño event - the anomalous warming of the eastern tropical Pacific Ocean - interacts with its atmospheric counterpart, the Southern Oscillation, temperature and precipitation patterns are affected throughout the tropics and into at least the lower reaches of the higher latitudes.

Although the ENSO is believed to be the most important contributor to year-to-year climate variability in many regions of the world, other phenomena are also believed to play a significant role in some regions:

Seasonal to Interannual Climate Variability Program Goal

The goal of the seasonal to interannual climate variability component of the USGCRP is to obtain a predictive understanding and the skills to produce forecasts of short-term climate fluctuations and to apply these predictions to problems of social and economic development in the United States and abroad.

Progress toward this goal will provide improved predictions that can, among other direct benefits, help farmers maintain their agricultural productivity in spite of extreme climatic events such as droughts and floods; help water resource managers to ensure reliable water deliveries and optimal reservoir levels; help in planning fishery harvests; and help foresters allocate resources effectively to safeguard forests (and the public) from fire during droughts.

Much progress has been made by the scientific community in developing the capability to predict, with reasonable certainty, incipient El Niño events and the related teleconnections (related atmospheric linkages to distant effects). These experimental El Niño forecasts are already being used with documented success in the tropics (where current prediction skill is highest) to maintain the productivity of the agricultural sector during ENSO- related periods of anomalous rainfall and temperature. Peruvians have been able to sustain the gross output of their agricultural sector, increasing it by 3% in 1987 in spite of the moderate 1986-87 ENSO event (in contrast to a 14% decrease in 1983, which accompanied the devastating 1982-83 event). In Ceara, Brazil, during the drought of 1991-92, a systematic effort to organize the timing of seeding, based on prediction information, maintained agricultural production close to the historical annual mean.

These early applications projects in Brazil and Peru demonstrate the potential social and economic returns from a continued national (and international) investment in "end-to-end" seasonal to interannual climate research. "End-to-end" refers to the application of research- based products to real issues of socioeconomic development and sustainability, with feedback from the information users to the scientific community to guide future research directions.

The U.S. economy is both directly and indirectly affected by climate fluctuations associated with ENSO. The economic benefits of improved forecasts of ENSO to the agricultural sector of the southeastern United States have been estimated to exceed $100 million per year. The economic value of improved forecasts to other U.S. regions is also likely to be large. Indirect effects of ENSO on the U.S. economy arise because the United States is part of the global marketplace. Many countries affected by ENSO events are developing countries with a high dependence on the agricultural and fisheries sectors as major sources of food supply, employment, and foreign exchange. Current assessments of these issues strongly suggest that research to support improved ENSO forecasting will bring significant benefits to the Nation.

Seasonal to Interannual Climate Variability Research Objectives

Due in large part to the international Tropical Oceans/Global Atmosphere (TOGA) program that was conducted from 1985-95, scientists can now predict with reasonable certainty (up to 1 year in advance) the onset of El Niño episodes in the tropical Pacific Ocean (see the figure on the back cover for an example of forecast skill). TOGA produced fundamental new knowledge of the processes that couple the tropical Pacific Ocean to the global atmosphere, and ultimately led to the emerging prediction capability. The USGCRP will continue in the coming year to build upon the success of TOGA as it participates in the Global Ocean-Atmosphere-Land System (GOALS) project of the international program on Climate Variability and Predictability (CLIVAR), undertaken under the auspices of the World Climate Research Programme (WCRP). In addition, the USGCRP will advance research geared to provide a greater predictive understanding of other climate processes that play a role in short- term climate fluctuations, through projects such as the Global Energy and Water Cycle Experiment Continental-Scale International Project (GEWEX/GCIP).

In FY97 and over the next several years, the USGCRP will build on its initial successes and support research activities geared to achieve the following objectives.

Objective 1 - Improve Prediction Skills, particularly over the United States

While the TOGA program made possible the ability to forecast El Niño events up to a year in advance, the forecasts are limited in that they focus on the evolution of the tropical Pacific and its related climate impacts. Forecast skill is highest in the tropics, near the source of an El Niño, and diminishes at higher latitudes (e.g., over North America) where other processes may play a greater role. The international GOALS program is designed to continue research necessary for continuous improvements of El Niño predictions and to extend predictability of climate fluctuations beyond the tropical Pacific to include the effects of the other tropical oceans, higher latitude oceans, and land-surface processes on seasonal to interannual climate variability, particularly at higher latitudes.

Objective 2 - Monitor the Tropical Pacific Ocean in Order to Better Determine its Influence on Climate, and to Improve Predictions

Variations in the tropical Pacific Ocean, particularly variations of sea surface temperature, exert a tremendous influence on the climate of many tropical and mid-latitude countries, including the United States. The USGCRP, in collaboration with its international research partners, has put in place a unique observation array of instruments to monitor constantly the state of the tropical Pacific Ocean and transmit data to research and operational centers in real-time. These data on current conditions provide the critical initial conditions needed in order to make more accurate forecasts.

Objective 3 - Map Global Precipitation and its Relationship to Climate Fluctuations

Rainfall distributions in the tropics and in several key locations outside the tropics are closely tied to large-scale atmospheric circulation patterns that are forced by the interactions between the atmosphere, land surfaces, and the oceans (see figure). By merging estimates from a wide range of ground-based and satellite measuring systems, the USGCRP, in cooperation with many international partners, has produced the first reliable maps of global precipitation. These developments were advanced by the international TOGA program, the International Satellite Cloud Climatology Project (ISCCP), TRMM science activities, and the International Satellite Land Surface Climatology Project (ISLSCP). Continued improvements in mapping global precipitation, advanced in part by the GEWEX/GCIP initiative, will benefit the global community through improved management of water resources and through better understanding of and ability to predict the climate system, to understand the controlling processes relevant to climate on seasonal to interannual time scales and regional to global spatial scales, and to develop predictive climate models.

Objective 4 - Incorporate Field Data into Models in Order to Improve Forecasts of Climate Variability

Air-sea interaction processes in the western tropical Pacific Ocean are important to the evolution of the ENSO phenomenon. High-quality data sets resulting from a recent international field campaign in the western Pacific are being analyzed in order to improve understanding of the coupling between the ocean and the atmosphere in this climatically important region. Process-based models will be modified to incorporate improvements in understanding.

Objective 5 - Assess Human Vulnerability to Climate Variations and Identify Options for Adaptation Based on Improved Information from Predictions

An understanding of the social and economic factors that render individuals, communities, and economic sectors more or less vulnerable to seasonal or yearly climatic fluctuations is critical for reducing that vulnerability and improving adjustment. To capitalize on advances in climate analysis and predictive capability, climate information needs to be incorporated into management decisions in climate-sensitive sectors (e.g., hydropower, insurance, transportation, fisheries, and agriculture). Moreover, lessons learned from adapting to natural variability will help society to be prepared to deal with the possibility that longer term climate change may manifest itself as changes in the frequency and magnitude of extreme events.

Objective 6 - Establish a Network of Research Centers to Improve Forecast Model Development and Diagnostics, and the Application of Predictive Information to Socioeconomic Planning Processes

To ensure that advances in climate prediction continue and are suited to the specific needs of affected populations, within and outside the United States, the USGCRP, led by NOAA, has established a Seasonal-to-Interannual Climate Prediction Program (SCPP), based on the evolution of existing USGCRP efforts to observe, research, model, and assess the interactions of the ocean, atmosphere, and land surfaces. The SCPP is based on an integrated approach that addresses climate variability from its origins in coupled atmospheric and oceanic behavior through its physical manifestations and socioeconomic impacts.

[see ENSO Diagram]

A fundamental component of the SCPP is the establishment of a multinational network of research and application centers to develop and issue experimental seasonal to interannual climate predictions based on global ocean-atmosphere modeling of interannual processes. One of these research centers will serve as the International Research Institute (IRI) for seasonal to interannual climate prediction, which will disseminate forecasts to nations and regions that are particularly affected by climate variability associated with the ENSO. Application centers will refine the global forecasts and tailor guidance to the specific conditions and needs of the localities they serve. At a high-level meeting convened by the United States in November 1995 (the International Forum on Forecasting El Niño: Launching the International Research Institute), countries and international organizations confirmed their support for the IRI and established an ad hoc working group to design an action plan.

[see Highlights of Recent Research on Seasonal to Interannual Climate Fluctuations]

Agency Contributions

Reflecting the complexity of the issue, several Federal agencies are associated with the USGCRP's endeavor to understand and predict seasonal to interannual climate variability. NOAA, NSF, and NASA are major contributors to this component of the USGCRP. DoD, USDA, DOI, and other agencies provide additional focused contributions. Each agency brings unique strengths and expertise to this coordinated effort:

Climate Change Over Decades to Centuries

Predicting Climate Change and Understanding its Implications for Society and the Environment

The growth and sustainability of human activities and the character of our environment are strongly influenced by the Earth's prevailing climate. Climate strongly affects the viability of agriculture, the extent of forests and rangelands, the diversity of flora and fauna, the availability of water, the spread of insects and rodents that carry human disease organisms, the intensity and frequency of floods and severe weather events, and much more. These forces influence the social and economic characteristics and success of societies.

Historical and geological records provide extensive evidence that climate has changed in the past in ways that have (or would have) significantly affected human activities. Research has provided important insights into the natural factors that caused major changes in the climates of the past. These factors tend to cause modest climate fluctuations on time scales of years to centuries and large- scale changes, with few exceptions, on time scales of millennia and longer.

Since the start of the Industrial Revolution 2 centuries ago, human activities have been having an effect on atmospheric composition. The current concentration of CO2 is about 30% above pre industrial levels as a result of combustion of coal, oil, and natural gas and as a result of clearing of land and plowing of soils for agriculture (see figure). The current concentration of methane is more than twice the pre industrial level due to land- and energy-related activities. One hundred years ago, rising emissions of CO2 spurred the Swedish scientist Svante Arrhenius to make the first quantitative estimate of the potential temperature change from an enhanced greenhouse effect. The estimate he made with respect to climate sensitivity is only slightly higher than current estimates; however, the change is occurring much more rapidly than his estimate, which was based on energy use at that time.

Extensive research, much of it funded during the last 20 years by the set of U.S. agencies that participate in the USGCRP, has been carried out to develop more precise and detailed estimates of how human activities will affect the long-term climate. To provide internationally recognized and authoritative scientific information about global climate change, its potential consequences for the environment, and the interactions between climate and society, the United States participates in the Intergovernmental Panel on Climate Change. The IPCC was established in 1988 by the United Nations Environment Programme and the World Meteorological Organization.

[see Carbon Dioxide vs. Time diagram]

The IPCC provides a mechanism for conducting a comprehensive assessment of the scientific literature on global climate change and its consequences and significance. To prepare these assessments, the IPCC brings together the leading researchers representing a wide range of disciplinary backgrounds and perspectives. It is asked to consider the findings from the world scientific community and, where possible, to reconcile competing views, to characterize alternative perspectives and viewpoints when consensus is not achievable, and to analyze the potential implications of uncertainties. In this way, the IPCC assessments serve two major purposes: (i) They provide a summary of the current state of the science for consideration by decision makers, and (ii) they enable the scientific community to take stock of current knowledge, identify areas of agreement and disagreement, and define areas for future research that will help to clarify such differences and advance knowledge to reduce key uncertainties.

[see Key Findings of the IPCC Second Assessment Report]

The research sponsored by the USGCRP on climate change, together with the results of the research programs of nations around the world, provides the supporting information for the IPCC assessments. The first comprehensive assessment was conducted in 1990. Interim reports were issued in 1992 and 1994 on special aspects of the issue. The Second Assessment Report was completed in 1995.

In its most recent scientific assessment, the IPCC came to a number of new conclusions. For example, the IPCC concluded that human activities most likely have caused an influence on the global climate over the last century that is becoming discernible from natural variations and that the human-induced effect is becoming larger than the natural climatic variations that have occurred over the past 1,000 years. The IPCC assessment, after reviewing the state of climate modeling, projected that during the next 2 centuries and beyond human influences will cause the climate to change more rapidly than during any known period in the last 10,000 years of human settlement. While some new opportunities for taking advantage of these changes are expected to emerge, human-induced climate change is currently projected, on balance, to cause significant disruptions to resource systems, societies, economies, and the environment (see the accompanying box and the FY96 Our Changing Planet for an introduction to scientific understanding of the potential for human-induced climate change).

Among the results of the IPCC assessment is the identification of limitations in scientific understanding and of areas where additional research would be particularly helpful in resolving remaining questions. In formulating the USGCRP research activities in this element of the program, the agencies focus on addressing the findings of the IPCC and the uncertainties identified by the National Academy of Sciences and the broader scientific community in their consideration of this issue.

Climate Change Program Goal

The goal of the climate change element of the USGCRP is to understand, predict, assess, and prepare for changes in the climate and the global environment that will result from the influences of projected changes in population, energy use, land cover, and other natural and human-induced factors.

Progress toward the goal will provide information needed by decision makers considering adaptive or mitigative responses to projected changes in climate and the associated environmental and societal impacts. The information will also assist planners and managers with responsibilities for the design of infrastructure and other major facilities, sustained management of natural resource- based systems, and long-term planning in the financial sector.

Research to achieve this goal requires a wide range of activities:

Together, these studies will provide a set of predictive tools and capabilities that can provide information for use by policy makers as they consider various options for responding, mitigating, or adapting to climatic change. The scientific ability to predict, even in a limited way, how the climate is likely to change will provide valuable information for decision makers seeking to ensure our continued prosperity, to reduce the exposure of the human population to health-related stresses, and to protect the overall vitality of the environment on which society depends. Increased understanding and enhanced prediction capabilities are required in order to provide the information needed by decision makers in considering actions to moderate future changes and to promote efficient adaptation to the changes that do occur.

Climate Change Research Objectives

Significant progress has been made over the past few decades in providing a broad-scale understanding of the role that human activities are playing and will play in the future in changing the global climate. While we have learned that human activities are changing the climate and that significant changes will occur in the future, significant gaps remain in understanding the regional patterns of climate change and the potential consequences and implications of climate change for the environment and for society. In FY97 and over the next several years, the USGCRP will continue to address significant uncertainties through support for research activities oriented toward the following key objectives.

Objective 1 - Quantify the Natural and Human- Induced Factors that Change Atmospheric Composition and Radiation

The most important human-induced factors that are forcing climate change include gases and aerosols (small particles) that are modifying the Earth's natural greenhouse effect by altering the fluxes of solar and infrared (heat) radiation balance. Changes in the land surface and its vegetation are also altering the Earth's reflectivity and hydrology. Quantifying the character and trends in these climate forcing factors is vital to understanding the causes of past changes and to predicting more accurately future changes in climate. In addition, understanding what is causing the changes in these factors will provide the basis for quantifying the effects of various mitigation options.

The most important results from recent research indicate that atmospheric aerosols, largely emitted from human activities, exert a non-uniform cooling effect over the globe. On average, this effect may be counterbalancing about half of the expected warming from the increase in the concentrations of greenhouse gases. In 1997, the USGCRP will continue to support studies of the cycles of greenhouse gases and of the generation and distribution of aerosols; these studies will be carried out in coordination with the atmospheric chemistry research component of the USGCRP. Studies to refine understanding of the global carbon cycle will focus on the role of terrestrial systems in carbon uptake and will be carried out in coordination with the land cover and ecosystem change research component of the USGCRP. Studies of volcanic and solar variability will be carried out to document natural factors that influence the climate.

Objective 2 - Characterize Natural Climate Variability and the Factors Contributing to Decadal and Longer Period Climate Fluctuations

Climate varies over many time scales. Over periods of a few years to decades, climate can be changed by volcanic eruptions, solar forcing, and natural fluctuations in the climate system. Paleoclimatic records reconstructed from ice cores and other sources of data provide evidence that the Earth's long-term climate varied significantly prior to about 10,000 years ago. However, since that time, the long-term climate has been relatively stable, especially over the past few 1,000 years. It is important to understand why this is the case, and what the prospects might be for a return to a significantly more variable climate.

Although the long-term climate has been stable, the evidence suggests that, during the last glacial period (which ended about 10,000 years ago), shorter term climate changes occurred over periods as short as a few decades. Data from the past 1,000 years suggest that there have been interdecadal swings in climate, creating periods of drought in some regions and excess moisture in others. Determining the character and causes of climate variability is thus essential as context for detecting that climate change has occurred and for determining the extent to which the changes are due to human activities. The natural variability component of the international CLIVAR program is being designed to improve understanding of natural changes in the climate.

Recent research has provided information on past changes in the Earth's climate (from historical records, ice cores, lake-level data, and other indicators). Evidence suggests that the melting of very large icebergs associated with glacial retreat can perturb ocean circulation patterns and result in relatively abrupt climate shifts over periods as short as decades. In 1997, research will even more intensively focus on interactions within the coupled atmosphere-ocean-ice system. The coupled processes appear to be important contributing factors to natural variations in the climate on inter- and multi-decadal time scales. Studies of solar variability and major volcanic eruptions as climate forcing factors on these time scales will also be carried out. Efforts will continue to reconstruct past climates of the Earth to improve understanding of the dynamics of climate change, with emphasis given to the study of warm climates to provide information for comparing to the warm climate now being experienced.

Objective 3 - Improve Quantitative Representations of Climate System Mechanisms and Feedback Processes

Predicting climate change requires a quantitative understanding of the climate system and of the mechanisms and feedback processes that determine its state. This understanding is needed to determine how the atmosphere, oceans, and land surface will be affected by the projected changes in greenhouse gases, aerosols, land cover, and other factors that are causing changes in the Earth's radiation balance. Available knowledge clearly indicates that changes in the radiation balance can be amplified or moderated by various feedback processes and mechanisms as the Earth system responds to these diverse forcing factors. Feedback mechanisms control whether the climate will respond strongly or weakly to human-induced changes. They also control how rapidly or slowly the Earth's climate will change. Reducing uncertainty about the magnitude of feedbacks is thus essential to providing more accurate predictions of how climate will change in response to alternative emissions scenarios for greenhouse gases, and to developing the capability to provide more accurate estimates of the regional patterns of climate change.

New and unexpected research results indicate that significantly more solar radiation may be absorbed by the atmosphere, both clear and cloudy, than is currently predicted by theory and climate models. Because this result is inconsistent with current understanding and is therefore controversial, it requires further observational confirmation. If confirmed, these new findings will require understanding the processes responsible for the currently unpredicted atmospheric solar absorption and a re analysis of the Earth's radiation balance, and could result in significant improvements in climate models. In 1997 and beyond, just as it has in earlier years, the USGCRP will continue to support broad-based and diversified programs of observations, field studies, analysis, and process-based modeling to improve understanding of coupling and interactions among aerosols, water vapor, and radiation in both cloudy and clear atmospheres; the hydrologic cycle; ocean circulation; biogeochemical cycling; land-surface/atmosphere interactions; and climate-chemistry feedbacks.

Objective 4 - Improve Scenario-Driven Predictions of Climate Change and Identification of the Human-Induced Component in the Recent Climate Record

Because of the historical uniqueness of the ongoing human-induced changes in atmospheric composition, predictions of future conditions for particular scenarios require the use of numerical, computer- based Earth system models. It is essential that these models - which are composed of traditional ocean and atmospheric general circulation models (GCMs) augmented by representations of the land surface, vegetation, chemistry, and the cryosphere (glaciers, snow, and ice) - be based on a comprehensive scientific understanding of the functioning of the climate system. The comprehensive understanding needed to develop and apply such models is developing rapidly from observational, process, and modeling studies. Such studies are starting to provide important insights into how the climate system has behaved in the past and how it will respond in the future to natural and human-induced forcing factors.

Over the past 10 years, as a result of USGCRP-sponsored research, atmospheric and oceanic GCMs have improved significantly and have strong potential for continuing advances through improved representations of critical climate processes and finer model resolution for regional-scale predictions. More accurate simulations of past climatic conditions are helping to improve confidence in the models by providing explanations for past changes and a quantitative identification of the human influence on recent climate. In FY97, research will continue to emphasize incorporation of carefully tested modules in climate models; enhanced use of the most powerful computers; coupling of atmospheric, oceanic, and land surface components of the Earth system; and testing and comparison of model simulations with observations as a means to evaluate the confidence that can be placed in model results. Studies to detect human-induced climate change will be continued with additional studies of the roles of various influences in contributing to climate change.

Objective 5 - Develop Improved Measures of the Sensitivity, Vulnerability, and Adaptability of Natural Ecological Systems and Managed Resource Systems and Project the Consequences of Climate Change and Long-Term Variations of the Climate

The potential impacts of climate change on natural and managed systems, human activities, and the economy are of great practical interest. Human activities that inadvertently influence climate are integrally intertwined with natural and managed resource systems. Examples include failure to optimize use of organic and chemical nitrogen fertilizer; degradation and clearing of forests; and shifts in land use between forest, range agriculture, and other uses. Given these many couplings, only limited progress has been made over the past 10 years in projecting the potential consequences to the environment of climate change. In addition, because accurate projections of regional changes in the climate are not available, the near-term focus must be on developing an understanding of the sensitivity and vulnerability of resource and societal systems to hypothetical changes that may occur over the next century.

Recent research results indicate that some plant species could potentially benefit from increased atmospheric concentrations of CO2. Experiments on the interactive effects of exposing agricultural crop species to different mixtures of atmospheric gases suggest that elevated CO2 concentrations may, for some species, mitigate the damaging effects of elevated ozone concentrations and improve their water use efficiency. However, some species, such as aspens, become more sensitive to increased concentrations of ozone if CO2 concentrations are elevated. In 1997, USGCRP studies will be continued that focus on the responses of terrestrial ecosystems (including agriculture, forests, rangelands, and polar ecosystems) and marine ecosystems to large- scale environmental change, including the enhancement of plant growth by the rising CO2 concentration. These studies will be coordinated with the efforts described in the land cover and ecosystems section of this report. Internationally, research will focus on sensitive ecosystems and regions that are experiencing multiple stresses in addition to climate change, and will be carried out in coordination with other nations.

Objective 6 - Develop Improved Measures of the Sensitivity, Vulnerability, and Adaptability of Socioeconomic Systems, and Project the Societal Implications of Climate Change and Long-Term Natural Variability

In order to develop a stronger capability for assessing the impacts of changes and the implications of alternative societal responses, research on the human dimensions of climate change must be carried out along with research on the behavior of natural and managed systems. An important effort will continue to be the enhancement of integrated assessment capabilities, including, but not limited to, the further development of integrated assessment models. In FY97, research to understand and improve the capabilities for estimating and accounting for the non-market aspects of climate change will be more actively pursued. In addition, efforts will be made to better enable coupling of findings relating to climate change with other aspects of environmental and societal change.

Human society and the natural and managed ecosystems upon which it depends are undergoing continual change as a result of many internal stresses and challenges. Prolonged changes in the climate over periods of decades to centuries will be an additional external influence, leading to further changes in societies and affecting their relationships to these systems. Research will continue to explore these linkages and better define the role of inadvertent human influences on the systems on which we depend.

Links to Users of Information through Assessment

Because climate is such a pervasive influence in human affairs, it is essential in studying climate to be able to assemble and systematically evaluate diverse sets of information - a process called assessment. The United States, through the USGCRP, has joined with other nations in supporting the Intergovernmental Panel on Climate Change as the mechanism for organizing climate change assessments. As explained in the international research cooperation section of this report, the USGCRP agencies have also assisted other nations in understanding their vulnerability to climate change through national studies and participation in the IPCC process.

To provide more specific information requested by international decision makers, the broadly based IPCC Second Assessment Report will be followed up with Technical Papers and Special Reports providing more focused information. In addition to research on the six objectives indicated above, the USGCRP will continue actively to participate in international assessments of climate change through the IPCC and will explore the opportunities for enhancing the resource base on the national implications of climate change. In addition, research results will be provided to national and State-level planners and decision makers so that regional vulnerability can be evaluated.

[see Highlights of Recent Research on Climate Change]

[see Hemispheric and Global Temperature Trends]

Agency Contributions

To conduct and support the interdisciplinary research needed for more accurate predictions of climate change and to provide a better understanding of its potential consequences and implications for the environment and society, the USGCRP agencies are committed to a coordinated, long-term research effort on climate change over decades to centuries. Because of the issue's complexity, research contributions are needed by multiple agencies. NASA, DOE, NOAA, and NSF play major roles in improving the projections of climate change, while USDA, DOI, EPA, and other agencies contribute to evaluating the potential consequences of climate change for society, ecosystems, and natural resources:

To assemble and assess the emerging information, the USGCRP agencies together support and participate in scientific assessments and in the development of enhanced integrated assessment capabilities.

Changes in Ozone, UV Radiation, and Atmospheric Chemistry

Understanding Atmospheric Chemistry and its Links to Human Well-Being

The recognition that many Earth System components - including the oceans, geosphere, terrestrial and marine biospheres, and cryosphere - are linked via the atmosphere is central to understanding global change. Geological records show that past climate change closely parallelled changes in the atmospheric abundance of the greenhouse gases carbon dioxide and methane, illustrating that changes to the atmosphere have the potential to perturb other major parts of the Earth system and vice versa. Because of this linkage, observations of atmospheric change may be early harbingers of climate change, and comprehending the reasons for atmospheric change is fundamental to understanding the potential for climate change.

As the global population nears 6 billion, human activities are inducing significant atmospheric change. This impact is clear, for example, in the firmly established linkage between emissions of CFCs - substances entirely of human manufacture - and the depletion of stratospheric ozone. Indeed, the awarding of the 1995 Nobel Prize in Chemistry to Professor Paul Crutzen, Professor Mario Molina, and Professor F. Sherwood Rowland for the demonstration of this linkage underscores the significance of this basic concept - that human activities can and do influence the global atmosphere and environment. As a consequence, an understanding of changes in atmospheric chemical composition and the implications of these changes is required if decision makers (e.g., the parties to the Montreal Protocol on Substances that Deplete the Ozone Layer and subsequent amendments and adjustments) are to choose among scientifically sound options.

The 1995 Nobel Prize in Chemistry also acknowledged the identification of the relationship between emissions at ground level and the chemistry of ozone formation and destruction in the stratosphere. This conceptual breakthrough, identifying the close coupling of Earth system components and phenomena, demonstrated that many environmental issues previously treated as unrelated are, in fact, interdependent. During the course of their studies on stratospheric ozone and atmospheric chemistry, all three scientists have been supported in part by funding from the agencies that support USGCRP research.

[see 1995 Nobel Prize in Chemistry]

Research has demonstrated that stratospheric ozone depletion not only causes increased exposure to ultraviolet light, but exerts a cooling influence on the global climate. Conversely, formation of tropospheric (lower atmospheric) ozone, a primary component of smog, not only pollutes the air, but induces a warming influence on the climate. Further, emissions of sulfur dioxide from fossil fuel combustion not only lead to the formation of acid rain, but contribute to aerosol haze, which exerts a cooling influence. Similarly, increases in surface-UV radiation exposure and its consequences are associated with depletion of the stratospheric ozone layer, but are also influenced by many non-chemical variables, such as cloudiness. And more subtly, changes in ozone levels in the troposphere influence the survival of certain ozone-depleting substances in their transit from the ground to the stratosphere.

The atmosphere does not segregate these chemical phenomena by scientific discipline, nor can the atmosphere be segregated from its interactions with the Earth system. Rather, there is one atmosphere, whose chemical changes can be properly understood only within the framework of a comprehensive and integrated Earth system research effort such as that of the USGCRP.

Atmospheric Chemistry Goal

The goal of the atmospheric chemistry element of the USGCRP is to understand and characterize the chemical changes in the global atmosphere and their consequences for human health and well- being.

Progress toward this goal will provide information to assist policy makers in protecting human health, in preserving the cleansing and protective qualities of the atmosphere, and in ensuring that new compounds do not lead to inadvertent environmental consequences.

Research to achieve this goal involves the following:

Together, these studies will provide an improved set of predictive tools and capabilities that can continue to provide information for use by policy makers as they consider various options for mitigating or adapting to global change. Successful examples of such output from the research of USGCRP abound: Human emissions of CFCs and halons have been unambiguously identified as the cause of the Antarctic ozone hole; projections that large increases in CFC emissions would lead to large losses of ozone underlie amendments to the Montreal Protocol to phase out CFC use; and observations of declining CFC growth rates and increasing abundance's of CFC substitutes demonstrate the efficacy of the policies adopted to protect the ozone layer.

Improved understanding of the chemical processes associated with ozone depletion is being used to assess the ozone-depleting potential of proposed CFC substitutes. One substitute used in air conditioning (HFC-134a) was recently shown to be benign to the ozone layer despite hypotheses to the contrary, thus avoiding an erroneous and costly recall by the U.S. automobile industry. This is a prime example of immediate economic payoff from understanding fundamental atmospheric processes.

Atmospheric Chemistry Research Objectives

The USGCRP atmospheric chemistry program focuses on meeting near-term information needs by establishing global chemical trends; characterizing atmospheric chemical processes, including ozone depletion, and their consequences; and assessing this information in terms of decision making. The objectives and near-term payoffs of the USGCRP's atmospheric chemistry research are as follows.

Objective 1 - Monitor Atmospheric Chemical Composition Trends and the Human-Influenced Emissions that Cause Them

"What is changing in the atmosphere and why?" The answer to this basic question is often the clearest sign of a changed relationship between humankind and the environment. For example, the slowdown in the growth rate of CFC concentrations demonstrates the impact of international decisions to phase out the production of these compounds (see the figure). To meet the need for ongoing monitoring, a combination of ground-, airborne-, and satellite-based studies are focusing on defining and explaining the trends in ozone, ozone-depleting substances and their substitutes, and greenhouse gases.

Updated information on long-term atmospheric trends can aid in monitoring global compliance with decisions, thereby offering accountability in science and policy. Also, they provide an "early warning system" for new issues, (e.g., unexpected chemical species and surprises in the growth rates of substitutes for the CFCs and halons).

Objective 2 - Understand the Stratospheric Ozone Variations during the Coming Most-Vulnerable Decade

Nations are committed to eliminating CFCs and halons, but development of practical, "ozone-friendly" substitutes requires a detailed understanding of the chemical processes responsible for ozone depletion. Further, despite such commitments, the ozone layer will be at its most vulnerable over the next decade, when peak halogen abundance's will occur, and during which time a cold, protracted Arctic winter or a large volcanic eruption could accelerate ozone depletion resulting from human activities. In fact, the causes of the observed global downward trends are not yet fully understood, nor are the full impacts of newly recognized threats to the ozone layer, such as methyl bromide and aircraft emissions. Therefore, investigations are including airborne field campaigns to elucidate atmospheric processes, coupled with laboratory and modeling studies to analyze the impacts of proposed substitutes and their potential for enhanced ozone depletion.

This understanding will help avoid costly missteps in the search for and development of appropriate CFC and halon substitutes, provide better forecasts and attributions of ozone changes over the next decade, and keep the decisions associated with "rehabilitation" of the ozone layer on a sound scientific basis.

Objective 3 - Monitor Changes in Surface UV Radiation, and Quantify Exposure and Consequences to the Biosphere and Human Health

Extended monitoring data on ultraviolet radiation are not currently available. The technical complexities associated with this task are challenging. Yet, such records are the raw material for assessing the impacts of enhanced UV exposure on ecosystems, materials, and human health, and are vital to public awareness of the dangers of increased exposure. Therefore, research is focusing on development and deployment of a network of UV-monitoring instruments, detection of trends in ground-level UV associated with ozone depletion, and studies of the impacts of enhanced UV on human health and ecosystems. Findings from this research should lead to an enhanced ability to model the global climatology of UV radiation, to improved characterization of radiation in atmospheric chemistry models, and to improved tests of model predictions using observations from UV networks.

A UV radiation exposure prediction and warning network could assist individuals to avoid potential adverse health effects. An understanding of how UV radiation initiates and promotes disease could lead to techniques to intervene before diseases such as skin cancer and cataracts are fully developed. The results of this research will constitute an improved scientific basis for policies to protect human health and the environment.

Objective 4 - Develop a Predictive Understanding of the Chemistry of the Global Troposphere

The lowest portion of the Earth's atmosphere (i.e., the troposphere) is intimately involved in the chemistry of global change. Natural tropospheric processes cleanse the atmosphere of most pollutants, thereby interrupting the transport of many ozone-depleting substances to the stratosphere and limiting the persistence in the atmosphere of the most common greenhouse gases. Accordingly, gaining a predictive understanding of tropospheric chemistry is central to efforts to protect the stratospheric ozone layer and to determine the climatic impacts of the aerosols and greenhouse gases that arise from surface pollution. Therefore, research is focusing on field campaigns designed to elucidate the chemical and mixing processes that control trace substances in the lower atmosphere, on space-based observations to achieve global coverage, and on modeling studies to test and refine prognostic capabilities.

A better understanding of chemical removal and other processes in the troposphere will help quantify the global warming potentials of human-influenced emissions and any potential environmental roles of aircraft. Better understanding will also provide the research base for addressing effectively the currently unknown, but inevitable, future issues associated with this part of the atmosphere, which is in direct contact with human activities.

Objective 5 - Characterize the Radiative Links between Atmospheric Chemistry and Climate Change

Stratospheric ozone depletion is now understood to introduce a cooling tendency in the climate system. In contrast, tropospheric ozone formation adds a warming tendency. In addition, chemically formed and other aerosols introduce a cooling influence, not only through their direct scattering of sunlight away from the Earth, but through their modification of the number and size of cloud droplets and their possible influence on cloud extent and persistence. Understanding these components, which is the next step to augmented climate-prediction endeavors, will require a blend of ground- to space-based observational studies, coupled with improved radiative theories and atmospheric chemistry models.

Improved knowledge of the links between atmospheric chemistry and climate change will help improve the level of confidence in scientific assessments (e.g., the expected IPCC assessment in the year 2000) regarding the detection and attribution of the climate changes that have occurred over the past several decades.

Objective 6 - Assess the Scientific Understanding of the Future of the Ozone Layer and of the Role of Human-Influenced Chemistry in the Radiative Forcing of Climate Change

In December 1995, in Vienna, Austria, the United Nations (UN) Montreal Protocol Parties called for an updated state-of- understanding assessment of the ozone layer to be prepared in 1998. The Conference of the Parties to the UN Framework Convention on Climate Change (UNFCCC) has requested an elaboration of specific issues covered in the IPCC Second Assessment Report, and is also expected to call for a full, comprehensive Third Assessment Report in the year 2000. Further, it is possible that the International Civil Aviation Organization will need similar scientific input regarding aircraft issues. Accordingly, the USGCRP will place an overall focus on near-term projects that will facilitate preparation of these assessments, including conducting special reviews of related atmospheric chemistry and physics, and communicating research findings to stakeholders, including Government policy makers, key private sector decision makers, and the public.

The result will be a continued and updated series of authoritative, community-wide, unbiased, and integrated assessments of the scientific, technical, and economic knowledge on which informed decisions can be based.

Links to Users of Information through Assessment

Information produced by the atmospheric chemistry research community is conveyed to decision makers and the public through a variety of channels, beginning with peer-reviewed scientific journals. Periodically, panels of leading scientists review and interpret this evolving literature in policy-relevant terms and publish consensus assessment documents such as the roughly triennial series, Scientific Assessment of Ozone Depletion, prepared under the auspices of the World Meteorological Organization and the United Nations Environment Programme to serve as the scientific input to the Montreal Protocol process. Another example of the assessment process is the series of Climate Change assessments, prepared under the auspices of the Intergovernmental Panel on Climate Change, which serve as one of the key inputs to the Conference of the Parties to the UNFCCC. In addition, information on new findings and their implications are regularly provided to Government and private- sector decision makers.

[see Highlights of Recent Research on Atmospheric Chemistry]

Agency Contributions

Several agencies work in close cooperation to gain a better understanding of atmospheric chemistry and its related issues. For example, the long-standing partnership and close coordination between NASA, NOAA, and NSF was a major underpinning of the highly effective research program in the late 1980s that provided the rapid understanding of the newly discovered Antarctic ozone "hole." Atmospheric chemical research has been augmented by selected programs sponsored by DOE and DoD. Further, the study of the impacts of ozone depletion and of the mitigative options has yielded, in concert with these agency efforts, an integrated information base for addressing this issue, with the primary emphasis on human health by HHS/NIH, with additional input from EPA, and on agricultural impacts and strategies by USDA. The component agency emphases are summarized as follows:

Changes in Land Cover and in Terrestrial and Marine Ecosystems

Global Ecosystems and the Dynamics of Sustainability

Changes in land cover and land use are occurring around the world at an increasingly rapid rate, as is the nature and configuration of our coastlines. Fisheries and marine ecosystems shift with changes in temperature and with human harvesting. Such changes are coupled in complex ways with the physical climate system, Earth system biogeochemistry, the vitality of ecosystems and sustainability of natural resources, and the societal activities associated with economic development and human migration.

The increasingly rapid rates of land-cover and land-use change and coastal alteration are driven largely by human activities. These activities are already beginning to threaten the continued provision of marketable goods and services produced in ecological systems through cultivation or harvesting (e.g., marine fisheries) and the effectiveness of ecosystem-level processes of importance to human activities (e.g., purification of water by forests and wetlands, regulation of water flow by forested watersheds, preservation of soil fertility).

The sustainability of these "ecological goods and services" depends on the recognition that (i) processes that control biogeochemical and hydrologic cycles are closely tied to and result in ecological goods and services; (ii) human influences that transform land cover and coastal areas from one type to another, or that change or intensify land- and coastal-management regimes, clearly affect the provision of ecological goods and services on regional scales and have the potential to affect their global availability and the chemical composition of the atmosphere on regional and global scales; and (iii) understanding the human influences on these processes is necessary in order to determine the potential for continuing provision of ecological goods and services to meet the needs of the expanding human population.

Ecosystems Program Goal

The goal of the land cover and terrestrial and marine ecosystems element of the USGCRP is to provide a stronger scientific basis for understanding, predicting, assessing, and responding to the causes and consequences of changes in terrestrial and marine ecosystems resulting from human-induced and natural influences.

Progress toward this goal will provide a stronger scientific basis for developing environmental and natural resource practices that are environmentally sound and practical, and that will ensure ecosystems yield sustainable benefits to humankind.

The effort to achieve this goal requires a wide range of activities. For example, observations are needed to document changes in land cover, coastal alterations, and ecological systems, including both natural changes and changes that result from human activity. Simultaneous in situ research is needed to quantify process rates and provide information for predictions of future ecological changes based on these processes. Combined information on patterns of change and processes causing these changes is needed to provide the foundation for evaluating landscape, coastal margin, and ecological changes due to global forcings (e.g., greenhouse gases, climate) as well as due to local and regional influences (e.g., watershed alterations, air pollution).

To take advantage of existing investments, new research efforts in land-use, land-cover, and coastal habitat change will be coupled to existing research programs and to data-gathering platforms and instruments that are already in place. To meet future research needs, new technologies and measurement capabilities will also be developed as necessary. Linkages will also be made to operational land-cover and coastal habitat classification and mapping efforts, both in the U.S. and abroad. The additional information to be derived from new and continuing observations will assist in the design of more sustainable management practices.

While some of the necessary measurements can be made from space, achieving the scientific understanding necessary to interpret and evaluate these observations cannot be done simply with data from remote sensing; other monitoring data are also necessary. An effective research program will require the cooperation of research communities and agencies with space-based, ground-based, ocean- based, and in situ research capabilities. Accounting accurately for land-use, land-cover, land-management, and coastal habitat change with fine spatial and temporal resolution, and carrying out the research needed for interpreting the findings, will necessarily require a partnership of many scientific and natural- resource management institutions around the world.

Ecosystems Research Objectives

Achieving the ecosystem research goal of improved understanding of land-cover and land-use change and changes in terrestrial and marine ecosystems will require achievement of several key objectives.

Objective 1 - Document the Current Patterns and Past Changes in Global Land Cover

During FY97, the USGCRP will continue to monitor and inventory the current land cover of the Earth at 1-km spatial resolution. USGCRP agencies are producing a series of data products documenting regional land cover and its relationship to underlying land use with data from the Advanced Very High-Resolution Radiometer (AVHRR) satellite instrument. This inventory establishes for the first time a systematically produced, replicable global database from which changes can be measured. This database will continue to be used in assessing regional temperature variability associated with coastal ecosystem stress.

Additional efforts will be made to classify and inventory the changes in land cover in North America and humid tropical forests at finer spatial resolutions. Several Federal agencies are cooperating to analyze Landsat satellite data (with a resolution of less than 100 m) and to classify and inventory the changes in land cover that have occurred in North America and the entire equatorial tropics since 1970. This effort will document changes that affect the functioning of ecological systems and provide the global change research community and policy makers with valuable and accurate estimates of changes such as shifts from forest cover to grass cover.

Objective 2 - Understand Natural and Human- Induced Influences that Lead to Changes in Land Cover, Land Use, Coastal Alterations, and Ecosystems

Distinguishing the causes of changes that are occurring and developing the ability to predict future changes requires improved understanding of the causes and mechanisms of change. The USGCRP agencies are working within the United States and with international partners in a number of regions around the world to understand the factors leading to and controlling land-cover, land-use, and land- management changes. In support of these efforts, ecological and biogeochemical research on the functional consequences of land- cover, land-use, and land-management changes and climatic variability is being conducted, and new efforts will be initiated in the vitally important Amazon River basin as the first stage of a multi- year, multi-partner international campaign known as the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA).

USGCRP-sponsored research will also examine how ecosystems react to change and influence global phenomena. For example, the accompanying figure provides an estimate of how future climate change may affect the distribution of an important tree species in the eastern United States. Research to examine ecosystem responses is being coordinated under the interagency programs on Terrestrial Ecology and Global Change (TECO) and Land-Margin Ecosystems Research (LMER). Program emphases follow:

In addition to process-based studies, continental-scale models of terrestrial ecosystems are being developed. In coordination with the International Geosphere-Biosphere Programme (IGBP) Global Analysis, Interpretation, and Modeling (GAIM) task force, scientists are analyzing current models and data, evaluating the capability of current models and experimental programs to meet the needs of decision makers and of those modeling the global climate and biogeochemical system, and advancing understanding of the links between global biogeochemical cycles and the hydrologic cycle.

[see Current and Projected Ranges of Beech Trees in the U.S.]

Objective 3 - Predict the Extent and Consequences of Changes in Land Cover, Land Use, and Ecosystem Processes, especially as They Relate to the Sustainability of Natural Resources and Economic Development

The USGCRP will participate in the international Land-Use/Cover Change (LUCC) Core Project. A comprehensive science plan has been developed for studying global land cover and land use to determine how these have varied over the past and to evaluate the current land-cover status. The program will use as a reference a combination of global coverage of land cover at 1-km spatial resolution, with selected areas represented at higher resolutions. LUCC will identify and examine the major human influences contributing to land-cover change in different geographical and historical contexts, and project changes that may occur over the next few decades - a focus that will require development of an understanding of the relationships between past changes in land cover and in the structure and function of ecosystems. This will include study of the societal and economic factors that also appear to be driving ecosystem changes.

As part of the USGCRP and the IGBP, the Land-Ocean Interactions in the Coastal Zone Program (LOICZ) will focus on the ecological systems at the interface of the coastal lands and seas. New and continuing studies will assess the linkages to terrestrial and shelf ecosystems and the influences of land cover, land use, and material inputs to the primary and secondary productivity of our coastal waters and estuaries, including the production of fish populations.

Objective 4 - Quantify Exchanges of Trace Gases between the Atmosphere and the Terrestrial Biosphere, with Particular Emphasis on the Processes Controlling Carbon Sources and Sinks

A network of stations measuring the uptake and release of CO2 will be expanded to include a representative set of native ecosystems and a variety of land-use and land-cover types. The network of measurements will be coordinated with research on processes (often conducted by measuring the isotopic composition of CO2) and with studies of climatic and human factors that influence terrestrial systems. Contemporary measurements and results from field and laboratory exposures of plants to elevated concentrations of CO2 will be used to refine scientific understanding of processes determining net carbon uptake by plants and soils. Estimates of carbon sources and sinks derived from atmospheric concentrations of CO2 will be used to improve the accuracy of predictions of future atmospheric CO2 concentrations. Results from field studies will also be related to observations of changes in land cover, historic records of changes in vegetation types, and measurements of carbon storage to address scientific issues related to the atmospheric sources and sinks of CO2. The information is needed to provide the scientific basis for consideration of response and mitigation options for stabilizing atmospheric CO2 concentrations.

Objective 5 - Observe and Document the Current Patterns and Past Changes in Chemical, Physical, and Biological Activity in the Oceans, especially Those that are Relevant in Understanding the Exchange of Carbon Dioxide with the Atmosphere

As part of the USGCRP and the IGBP, interagency participation in the U.S. Joint Global Ocean Flux Study (JGOFS) will continue. Efforts are focused on characterizing the global geographic distribution of key biogeochemical properties and rate processes pertinent to the oceanic carbon system, as a necessary prerequisite to predicting change in the ocean system and its interactions with atmospheric carbon pools. The focus of JGOFS in FY97 will be the Southern Ocean around Antarctica:

Results are needed to document how the oceans exchange CO2 with the atmosphere as a basis for understanding the role that marine ecosystems play in carbon transports, as well as to investigate the effects of natural and human-induced climate change on marine ecosystems and to assist in applications to coastal fisheries and ecosystem management.

Objective 6 - Understand and Analyze the Chemical, Physical, and Biological Processes that Regulate Ocean Uptake and Release of Atmospheric Carbon Dioxide and that Control Biological Productivity in the Oceans, and Develop the Predictive Capabilities Needed to Ensure the Sustainability of Marine Resources

Understanding what has happened and predicting what may happen requires research to understand chemical, physical, and biological processes:

The development of models will be encouraged in order to simulate the interactions of marine biological communities with their chemical and physical environment. Creating coupled physical and biogeochemical models of the ocean for the purposes of testing our understanding and improving our ability to predict future climate- related change will be pursued as part of the JGOFS program. When validated, these models will be used to predict the consequences of physical and biological changes for the exchange of CO2 with the atmosphere. Different models will be used to evaluate the effects of changes in marine phytoplankton and zooplankton on fish populations.

Scientists will begin using basin-wide circulation models and climate- scale changes in the investigation of how changing physics in the ocean will likely affect the distribution, abundance, and productivity of marine animals. Under the auspices of the USGCRP and IGBP, Global Oceans Ecosystems Dynamics Program (GLOBEC) research will continue to link climate variables with plankton productivity, and ultimately fish production, on wide time and space scales in order to better interpret past changes in animal abundance, as well as predict potential future changes in response to global climate change. Sorting out natural variability in the physical and biological system from that caused by progressive and human-induced changes is vital to the assessment:

The LOICZ program will include research on organic carbon dynamics in coastal zones.

Links to Users of Information

Because ecosystems provide such valuable goods and services for society, there is widespread interest in understanding how ecosystems are changing and what is causing these changes. Within the United States, intense attention is being devoted to this issue by the land management agencies as they seek to improve capabilities for sustainable management of our Nation's land resources. Findings on research on these aspects of ecosystems are made available in many ways, including through agency planning reports on land- management practices.

In addition, because changes in carbon storage on land can lead to changes in the atmospheric concentrations of CO2, it is essential to have the information and understanding needed to understand the relative roles of fossil fuels and biomass conversion, and the potential for sequestering carbon in ecosystems. Reporting of results relating to the carbon cycle is carried out through studies that become the basis for IPCC findings.

[see Highlights of Recent Research on Land and Ocean Ecosystems]

Agency Contributions

Research on changes in land cover and in terrestrial and marine ecosystems is shared among a number of agencies, each of which brings its own particular history and strengths to bear. NSF- supported basic research on ecosystems and ecological processes has provided the scientific foundation on which other agencies' programs have been built. Because of its coupled strengths in remote sensing and in organizing and contributing to field programs, NASA plays a major role in the study of terrestrial and marine ecosystems. NASA emphasizes the use of remote-sensing data in landscape, regional, and global ecosystem models. New remote-sensing capabilities have been especially useful in collaborative studies within the United States and with other nations, particularly those working to understand and preserve their vulnerable ecosystems. DOE has emphasized the interplay of rising atmospheric CO2 and physiological processes in ecosystems. USDA, DOI, NOAA, and EPA have focused on the implications of global change for their direct land-management responsibilities (in the case of USDA and DOI), and more broadly on their responsibilities to protect the environment. Within the United States, USDA and DOI manage public forest and rangelands and have major responsibilities for policies affecting privately owned agricultural lands, forests, and grasslands. Agency emphases follow:

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