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However, core research has tended to focus along classical disciplinary lines rather than on the coordinated, long-term, cross-disciplinary monitoring activities that are essential for documenting how and why the Earth's environment changes. The fundamental sources of information will be data bases that are built up slowly over relatively long periods, and the interpretation of the changes that occur will involve cross-disciplinary analyses that use information from many such data bases. To be effective, global change research must transcend existing disciplinary barriers and encourage interactions that cross disciplinary lines. Such interactions are currently difficult to establish.

This chapter assesses specific ongoing and planned research activities most relevant to solar influences on global change, and then discusses some programmatic issues. The core research programs that exist at present neither accommodate nor foster cross-disciplinary global change research needs. Measuring and modeling the variations in energy input from the Sun to the Earth is essential for research on solar influences on global change. But it is not a prime goal of existing or planned solar physics research, since knowledge of solar processes is better achieved with highly spatially resolved observations of portions of the solar disk. Nor is it a prime goal of Earth science research, for which it is an initiator but not an indicator of the physical processes of interest. As a distinct cross-disciplinary task, the study of solar influences on global change is championed by neither the Earth science nor the solar astrophysics community.

Monitoring Solar Forcing

Reliable measurements of solar energy inputs to the Earth system extend over less than 20 years (which is less than two solar activity cycles). Existing measurements indicate significant variability of essentially all solar parameters on essentially all time scales, from minutes to decades. In acquiring a suite of solar irradiance measurements with sufficient long term precision for global change research, important aspects of space based solar metrology obtained from the experiences of the 1980s must be used to guide research strategies for the 1990s and beyond.