CIESIN Thematic Guides

The Importance of Satellite Remote Sensing for Global Change Research

Global change research poses significant challenges to the scientific community. Physical and biological scientists (together referred to as natural scientists) have grappled with the challenges of data requirements for a decade or more and have identified the utility of satellite remote sensors as major sources of consistent, continuous data for atmospheric, ocean, and land studies at a variety of spatial and temporal scales. An extensive body of literature within numerous natural science disciplines documents the development of, or potential for, satellite sensor data analysis techniques to identify environmental attributes and monitor physical and biological processes relevant to global change research.

Satellite sensor data have proven useful to the atmospheric and ocean sciences communities. While social scientists may have little involvement in the scientific study of the biological, physical, and chemical processes being addressed within these communities, human dimensions interests are associated with the causes of the perturbations to atmospheric and ocean systems being studied and in the resultant health and socioeconomic effects on humans. In "The Use of Satellites to Monitor Global Transmission of Microbes," Simmer and Volz (1993) address the effects of atmospheric dispersion of disease on human health by discussing the use of satellite sensors for monitoring terrestrial and atmospheric parameters relevant to microbial spread and transmission. In "Health and Climate Change: Marine Ecosystems," Epstein, Ford, and Colwell (1993) discuss the human health implications associated with the degradation of marine ecosystems due to pollution and global warming. The CIESIN Thematic Guide on Human Health and Global Environmental Change provides information on use of remote sensing and geographic information systems (GIS) in Programs for Surveillance, Treatment, and Control of Vector-borne Diseases. Clark (1993) reviews the applications of satellite sensor data to a wide range of marine pollution problems in "Satellite Remote Sensing of Marine Pollution."

The land sciences community has made extensive use of satellite image data for mapping land cover, estimating geophysical and biophysical characteristics of terrain features, and monitoring changes in land cover. For example, in "Applications of NOAA AVHRR 1-km Data for Environmental Monitoring," Ehrlich, Estes, and Singh (1994) review many of the reported findings associated with defining the capabilities of NOAA Advanced Very High Resolution Radiometer 1-km data to provide global land-cover information. Goward (1989) discusses the current and future role of satellite image data for contributing to studies of bioclimatology. in "Satellite Bioclimatology." Tucker, Dregne, and Newcomb (1991) use coarse-resolution satellite image data for monitoring continental-scale climate-related phenomena in "Expansion and Contraction of the Sahara Desert from 1980 to 1990." Colwell and Sadowski (1993) use high-resolution satellite data for monitoring regional patterns and rates of forest resource utilization in "Past Patterns as a Guide for Future Forest Management." And Freeman and Fox (1994) discuss the semi-operational use of satellite image data by several forest assessment programs in "Satellite Mapping of Tropical Forest Cover and Deforestation."

More recently, the scientific community has witnessed a growing emphasis placed on investigating the human dimensions of global change. In 1990, the International Social Science Council (ISSC) launched its Human Dimensions of Global Environmental Change Program to serve as the international social science research program on global change that would parallel and complement major natural science global change research efforts, namely, The World Climate Research Program (WCRP) and The International Geosphere-Biosphere Program (IGBP).

In the defining document of the HDP, A Framework for Research on the Human Dimensions of Global Environmental Change, Jacobson and Price (1990) identify seven topics of research central to understanding the interactions of human activities and the environment. These topics include the following:

In identifying the research topics, Jacobson and Price state:

"Each of these topics must be investigated separately. In addition, they must be investigated in combination as they interact in specifically defined contexts where human activities have a direct impact on the physical, chemical, and biological processes that are involved in global environmental change. Such research must be conducted at all geographical scales and should include the past as well as the present and the future."

(Emphasis added.)

Such commentary advises that to be most effective, human dimensions studies of global change must be "grounded" within the context of specific nature-society issues, geographic locations and scales, and time scales. Turner and Meyer (1991) further develop this precept by emphasizing the importance of particular space-time relationships in affecting human behavior in "Land Use and Land Cover in Global Environmental Change." In discussing the topic of land-use and land-cover change as a type of global environmental change, they maintain that macro-level driving forces of land use/cover change (such as population growth, technological change, economic development, socioeconomic organization, and attitudes/beliefs) are frequently modified by significant contextual variables and may therefore be inadequate for explaining types and rates of change. The authors advocate the regionalization of characteristic situations of society-land cover interactions on a global scale. A global set of regional situations that characterize deforestation, for example, would enable exploring relationships among macro-level driving forces and meso- and micro-level contextual variables.

Defining and locating various types of society-land cover interactions for study may pose new challenges for social scientists. Miller (1994) and Jacobson and Price (1990) note that social scientists studying global change should consider increasingly the spatial relationships associated with various physical land characteristics or anthropogenically induced land surface conditions for guiding the scale and extent of their data collection. Satellite remote sensors can serve as major sources of data on the effects of human behavior within the biosphere, enabling the establishment of the spatial scale and extent of the direct interaction of humans with the global land cover.

Ultimately, determining the integrated linkages between the human dimensions driving forces and the physical processes of global change will require collaboration among scientists from the human and natural science domains. Miller (1994) has called attention to the problems inherent to attempting collaboration and the new methodological paradigms needed to develop collaborative, interdisciplinary research in "Interactions and Collaboration in Global Change across the Social and Natural Sciences." Collaborative research will enable diverse disciplines to effectively hypothesize and study the linkages. Miller advises that in the initial stages of study, researchers should seek interdisciplinary agreement in defining global change research problems in their entirety, from anthropogenic forcing functions to their expression in physical or ecological processes to their subsequent impact on human society.

In "CIESIN's Experiences with Integrated Global Change Research," Thomas and Roller (1993) discuss the results of the Consortium for International Earth Science Information Network's (CIESIN) 1991 Science Pilot Project Program, which demonstrate the value of satellite remote sensing in facilitating interdisciplinary global change research. Satellite image data record a variety of phenomena, some of which relate to the human sciences, some to the physical sciences, and many to both. The data provide a common spatial frame of reference for integrating interests within the scientific community to promote the interdisciplinary research essential for understanding and managing global change. In "Integrating Regional Studies of Deforestation into a Global Change Context," Thomas et al. (1993) provide an example of use of satellite image data to contribute to regional studies, and then integrate those results into a global change context.