Strategic Plan for the
Climate Change
Science Program
Final Report, July 2003

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Vision for the Program and Highlights of the Scientific Strategic Plan

Acronyms, Abbreviations,
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Land-use and land-cover are linked to climate and weather in complex ways. Key links between changes in land cover and climate include the exchange of greenhouse gases (such as water vapor, carbon dioxide, methane, and nitrous oxide) between the land surface and the atmosphere, the radiation (both solar and longwave) balance of the land surface, the exchange of sensible heat between the land surface and the atmosphere, and the roughness of the land surface and its uptake of momentum from the atmosphere. Because of these strong links between land cover and climate, changes in land use and land cover can be important contributors to climate change and variability. Moreover, reconstructions of past land-cover changes and projections of possible future land-cover changes are needed to understand past climate changes and to project possible future climate changes; land-cover characteristics are important inputs to climate models. In addition, changes in land use and land cover, especially when coupled with climate variability and change, are likely to affect ecosystems and the many important goods and services that they provide to society. The National Research Council recently identified land-use dynamics as one of the grand challenges for environmental research (NRC, 2001b).

Figure 6-1: Land use: strip cropping and woodlots in Leelanau County, Michigan. Source: USDA, Natural Resources Conservation Service (photo by Lynn Betts, 2001).

Determining the effects of land-use and land-cover change on the Earth system depends on an understanding of past land-use practices, current land-use and land-cover patterns, and projections of future land use and cover, as affected by human institutions, population size and distribution, economic development, technology, and other factors. The combination of climate and land-use change may have profound effects on the habitability of Earth in more significant ways than either acting alone. While land-use change is often a driver of environmental and climatic changes, a changing climate can in turn affect land use and land cover. Climate variability alters land-use practices differently in different parts of the world, highlighting differences in regional and national vulnerability and resilience.

The interaction between land use and climate variability and change is poorly understood and will require the development of new models linking the geophysics of climate with the socioeconomic drivers of land use. Providing a scientific understanding of the process of land-use change, the impacts of different land-use decisions, and the ways that decisions are affected by a changing climate and increasing climate variability are priority areas for research.

In addition to being a driver of Earth system processes affecting the climate, carbon cycle, and ecosystems, land-use and land-cover change is a global change in its own right, requiring its own research foundation. Key issues to be addressed by this research element include the spatial and temporal dynamics of land-use change, the role of fragmentation and degradation, the role of multiple drivers, the role of institutions, and the interactions among drivers and types of land-use change.

This research element provides the scientific underpinning for land-use decisionmaking and projections of future land use, and has substantial benefits beyond climate change assessment and mitigation by supporting a wide array of issues important to users of this information. To meet multiple objectives, the land-use and land-cover change research element will address two overarching questions:

To address these overarching questions, a focused, integrated research agenda is required that includes process studies, systematic observations, modeling and prediction, retrospective studies, research on impacts, and regional science networks and assessments. In addition, research collaboration with other program elements will be necessary to gain detailed understanding of the direct impacts of land-use and land-cover change on climate, as well as the combined effects of land use and climate change on ecosystems, water, and carbon cycles. Answers to the overarching questions will require research focused on the five specific questions posed below.

During the previous decade, significant progress was made in planning and launching satellites with instruments suited for Earth observation. In addition, a number of national- to global-scale experimental land-cover databases were developed that led to increased use of land cover in climate and carbon cycle models. Methodological advancements were also made. As a result, there is an improved capability for and strong reliance on remote sensing and land-cover databases for multi-scale environmental studies. The research and development associated with this question involves the continuation of, and improvements in, data collection systems and data products. This will provide new information leading to regular updates of land-cover databases at scales relevant for issues ranging from local resource management to global-scale analyses.

While remote sensing provides quick and comparatively inexpensive information about land-cover changes over large areas, land-cover database improvements will require integration of data from ground-based networks (see Figure 6-2). These networks offer a wealth of historical data (often with data records extending back 50-100 years), and can provide detailed site information (e.g., primary production, species composition, habitat quality, wildlife population statistics, soil type, tillage and crop rotation history, and land-use classifications). Integrating ground-based and remote sensing data collection systems provides an opportunity to vastly improve the speed and quality of land-use and land-cover data for use in applied research. Much of our understanding of land-use and land-cover change has built up from individual case studies, using both remote sensing and ground-based data, and we will continue to rely on case studies as a means to gain required knowledge.

Evolving public and private land management questions call for new data and information and improved scientific bases for decisionmaking. They also require long-term continuity in data collection, and the acquisition of data at the global scale. Coordination and prioritization of the specific land-use and land-cover change data requirements with the Observing and Monitoring element is imperative. Methods and procedures now exist to make routine global observations of land cover, but there is currently no operational program. With the current suite of satellite sensing systems and archived data sets available to the research community, studies at the large spatial scales needed to depict land-cover and management changes can begin.

While considerable progress has been made in mapping land-cover characteristics, the ability to accurately map the wide range of landscape attributes, including land use and biomass, will require a considerable research effort. Coordination of existing in situ data collection efforts, and the retrieval, analysis, and integration of historical data are needed to extend the usefulness of existing data and to enrich and standardize data attributes in future data collection and use. In addition, improvements in remotely sensed data quality and in automated algorithms for detection of local land-cover changes and their characteristics are needed. Data integration will be particularly important so that in situ, remotely-sensed, and other forms of data can be merged and used to derive the needed land-use and land-cover information. As scientific demands and needs for land-use and land-cover information change, parallel innovation in the resulting data products will be essential.

The ability to forecast land-use and land-cover change and, ultimately, to predict the consequences of change, will depend on our ability to understand the past, current, and future drivers of land-use and land-cover change. These factors as well as other emerging social and political factors may have significant effects on future land use and cover. Patterns of land use, land-cover change, and land management are shaped by the interaction of economic, environmental, social, political, and technological forces on local to global scales (see, for example, Figure 6-3).

An improved understanding of historical land-use and land-cover patterns provides a means to evaluate complex causes and responses in order to better project future trends of human activities and land-use and cover change. We must understand the primary modern and future drivers of land use and their interrelationship with land management decisions and resource policies to develop projections of future land use and management decision outcomes under a range of economic, environmental, and social scenarios. This ability will allow better projections and hopefully minimize negative impacts, especially as related to climate change. This type of analysis will require the integration of various disciplines from the physical and social sciences.

Figure 6-3: Land cover change in eastern U.S. ecosystems, 1973-2000. An analysis of land-use and land-cover change in the eastern United States provides evidence of distinctive regional variation in the rates and characteristics of changes. The color of each ecoregion indicates the rate of change, while the pie charts indicate the type of change. In some areas, rapid, cyclic harvesting and replanting of forests was the main cause of change, while urbanization dominated in other areas. Source: USGS EROS Data Center. For more information, see Annex C.

An innovative approach is needed to quantify, understand, model, and project natural and human drivers of land-use and land-cover change. Research is needed to understand and project the interactions of economic, social, and environmental choices on land-use and land-management policies and decisions. New techniques and tools that integrate understanding of human behavior, opportunities, consequences, and alternatives are needed for improved decision- and policy-making. There must be close collaboration with the Human Contributions and Responses research element to understand the social and economic drivers that affect human choices.

Improvements are needed in process models of land-use and land-cover change dynamics in space and time, combining field-level case studies for analysis of processes and management systems, statistical studies for large regions, and empirical analyses using remote sensing at local scales. This process-level understanding of land use and cover dynamics and interactions with socioeconomic and biophysical factors will aid the analysis of land-use and land-cover change across scales. Work is needed to understand the interactions between agents or causes of land-use change and climate change and variability.

To understand the historical, contemporary, and future linkages between land-use and land-cover change and its resulting effects on biogeochemical cycles, climate, ecosystem health, and other systems, it will be necessary to make significant advances in documenting the rates and causes of land-use and land-cover change. Our current understanding of historic land-use and land-cover change is weak due to the anecdotal or very local nature of past research in this area. Future understanding of land-use and land-cover changes will be greatly improved through new systematic methods and study designs for land-use change research. To understand the forces of change that operate at different scales, it will be necessary to conduct studies that explicitly reveal the local and regional variations in land-use and land-cover changes. With this, the historical and contemporary data needed to develop models that project land use and land cover for specific intervals into the future will be produced.

Figure 6-4: The map on the left shows actual land use in the seven-county area of central Maryland in 1994, while the map on the right is the predicted distribution of land use types based on a �polycentric' city model. There is remarkable similarity between the two maps in commercial, high, and medium densities, but disagreement in the low-density residential category. Models with improved projections of this fragmented, low-density residential development -- which consumes a disproportionate amount of open space and causes high public service costs -- will better support decisionmaking regarding this type of development. Source: Nancy Bockstael, University of Maryland. For more information, see Annex C.

A new suite of models that combine climatic, socioeconomic, and ecological data to model projected changes at scales that are relevant to resource management to those relevant for global assessments is needed. This need for predictive models calls for a better understanding of the drivers of land-use change, characterization / parameterization of land-use elements, and credible predictions of land cover and land use at annual to decadal time scales. Partnerships are needed with state and regional assessment and research efforts, to ensure comparability between national/global and state/regional models. Integration among the Carbon Cycle, Ecosystems, and Human Contributions and Responses research elements will be needed to develop and test models for generating scenarios of land-use and land-cover change, and making projections of change that take into account the various influences of ecosystem functioning, carbon, water, and energy cycling as well as human-managed systems. Model validation will be a particularly challenging element of this research area. Simulation of past conditions will be a necessary strategy for testing the performance of models, placing more significance on the need to understand land-use and land-cover change in both historical and contemporary contexts.

Land-use and land-cover change is linked in complex and interactive ways to global climate change, and the feedback between the two exists at multiple spatial and temporal scales. Changes in greenhouse gas emissions, albedo, and surface roughness are the primary mechanisms by which land-use and land-cover change affect climate. Climate variability and change, in turn, can affect the ways in which land is used and the land cover of a given area. Some of the impacts of these feedbacks are local while others have global ramifications. For example, trace gas emissions and removals by sinks depend strongly on land cover and land-use practices (see, for example, Figure 6-5), while the deposition of atmospheric constituents affects the potential rate and magnitude of terrestrial sinks.

Figure 6-5: Increasing atmospheric carbon dioxide (CO2), climatic variation, and fire disturbance play substantial roles in the historical carbon dynamics of Alaska. Analyses of stand-age distribution in Alaska indicate that fire has likely become less frequent compared to the first half of the 20th century. Application of the Terrestrial Ecosystem Model indicates that regrowth under a less frequent fire regime leads to substantial carbon storage in the state between 1980 and 1989. Source: David McGuire and Dave Verbyla, University of Alaska, Fairbanks. For more information, see Annex C.

Simulation of climate-land use/cover feedbacks will require advancement of current understanding of multiple stress processes at local to global scales. We need to identify past changes in land use and land cover that are attributable to changes in climate, in order to project future changes in land use and land cover that could result from changes in climate. Validation of the interacting climate-land use effects for specific regions of the globe will be particularly challenging. Inputs will be needed from the Climate Variability and Change, Water Cycle, and Carbon Cycle research elements. International cooperation will be needed to optimize the currently existing and emerging observational networks.

There is clear evidence that changing land use and land cover has significant impacts on local environmental conditions and economic and social welfare. For example, the water cycle depends heavily on vegetation, surface characteristics, soil properties, and water resources development by humans (e.g., dam construction, irrigation, channeling, and drainage of wetlands) which in turn affects water availability and quality. Land-use and land-cover change, climate variability and change, soil degradation, and other environmental changes all interact to affect natural resources through their effects on ecosystem structure and functioning. In turn, ecological systems may respond unexpectedly when exposed to two or more perturbations. The following research questions address the effects of changes in land use and land cover on other research elements (i.e., Ecosystems, Water Cycle, Carbon Cycle, and Human Contributions and Responses).

The other Climate Change Science Program (CCSP) research elements provide complementary information about the environmental and biophysical forces that influence potential land uses (e.g., atmospheric chemistry and processes, climate variability and change, water resources, nutrient flows, and ecological processes) and the anthropogenic pressures that will give rise to various land uses and processes (e.g., the Human Contributions and Responses element). Development of coupled climate-land use/cover models, that incorporate socioeconomic factors and ecosystem function, should be accelerated. The challenge will be to use contemporary impacts of land-use and land-cover change to calibrate impacts on ecosystem goods and services; biogeochemical, water, and energy cycles; and climate processes. Research will require multidisciplinary cooperation to develop land use and land cover projections that address the necessary spatial and temporal scales, and include the necessary physical, biological, and social factors of interest, to ensure that projections of land use and land cover can be incorporated into models of impacts.

Nationally, several programs have identified land-use and land-cover change as part of their individual agency research agendas (e.g., the National Aeronautics and Space Administration, the U.S. Geological Survey, the National Science Foundation, the U.S. Environmental Protection Agency, and the U.S. Department of Agriculture) and have played an active role in developing this research element. It will be important as the program proceeds to engage multiple agencies and organizations working in this and related fields (e.g., the National Institutes of Health, the Department of Transportation, the Bureau of Land Management, and the U.S. Agency for International Development). In the next decade of global change research it will be particularly important to include stakeholders (e.g., the National Governors Association, non-governmental organizations, and state and local land managers) in guiding this research element.

Global change research is strengthened through international partnerships. In the next 10 years, the establishment of international land-use and land-cover science programs will augment ongoing efforts such as the International Geosphere -- Biosphere Programme to help bridge the gap between climate change researchers, land managers, and decisionmakers. For example, the Global Observation of Forest Cover and Global Observations of Land Cover Dynamics (GOFC -- GOLD) is a new program and part of the Integrated Global Observing System (IGOS) for coordinating global land observations. GOFC -- GOLD is implemented through regional networks of data providers and users to address a combination of global change and natural resource management questions, and engages local scientists with local and regional expertise and knowledge. Regional observational and monitoring networks and associated case studies are key to understanding phenomena at fine scales, and provide a test bed for models and a mechanism for comparative analysis.

Another example is the United Nations (UN) Land Cover Network -- an emerging cooperative activity of the UN Food and Agriculture Organization (FAO) and the UN Environment Programme (UNEP) to develop monitoring and measurement of land-cover change in support of their global environmental outlooks and assessments (e.g., the Millennium Ecosystem Assessment). In addition to these activities, development agencies are attempting to address questions concerning the societal impacts of global change through new programs such as USAID's Geographic Information and Sustainable Development program. Such programs can help in strengthening the scientific underpinning for the decisionmaking process.

To facilitate the U.S. science community achieving broad science and societal objectives in global land-use and land-cover research, international partnerships are being formed for regional studies of global importance. For example, during the last 10 years studies of the Amazon have been conducted in the framework of the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA), a cooperative international project led by Brazil. Created through an international cooperative agreement, LBA has important institutional relations, including ties with over 40 Brazilian institutions, 25 institutions from various Amazonian countries, as well as institutions from the United States and 8 European nations. The LBA project is expected to continue for at least 3 years.

During the next 3-5 years, the Northern Eurasia Earth Science Partnership Initiative (NEESPI) will produce a large-scale, interdisciplinary program of research aimed at developing a better understanding of the interactions between ecosystems, the atmosphere, and human dynamics in northern Eurasia. This region, representing a quarter of the world's land masses, will be studied by U.S. scientists in partnership with scientists from northern Eurasia to enhance scientific knowledge and develop predictive capabilities to support informed decisionmaking with respect to land-use and land-cover changes.