Toward an understanding of global change

In the international scientific community, the International Council of Scientific Unions has organized the International Geosphere Biosphere Program (IGBP) to address the problems of global change. The objective of the IGBP is to describe and understand the interactive physical, chemical, and biological processes that regulate the total earth system, the unique environment that it provides for life, the changes that are occurring in this system, and the manner in which they are influenced by human activities. The IGBP is currently in its preparatory phase, during which the program's goals and research components are slowly evolving and coming into focus. In this report, a limited number of high-priority research initiatives are recommended for early implementation as part of the U.S. contribution to the preparatory phase of the IGBP. The recommendations are based on the committee's analysis of the most critical gaps, not being addressed by existing programs, in the scientific knowledge needed to understand the changes that are occurring in the earth system on time scales of decades to centuries. These initiatives will build upon the capabilities of the U.S. program in global change.