Introduction

Abstract

At present there is enormous concern about the changes that are occurring on the surface of the earth and in the earth’s atmosphere, primarily as a result of human activities. These changes, particularly in the atmosphere, have the potential for altering the earth’s habitability. International programs unprecedented in scope, including the International Geosphere-Biosphere Program, have been initiated to describe and understand these changes. The global change program will call for coordinated measurements on a global scale of those interactive physical and biological processes that regulate the earth system. The program will rely heavily on the emerging technology of remote sensing from airborne vehicles, particularly satellites. Satellites offer the potential of continuously viewing large segments of the earth’s surface, thus documenting the changes that are occurring. The task, however, is not only to document global change, which will be an enormous job, but also to understand the significance of these changes to the biosphere. Effects on the biosphere may cover all spatial scales from global to local. The possibility of measuring biosphere function remotely and continuously from satellite imagery must be explored quickly and thoroughly in order to meet the challenge of understanding the consequences of global change.