9523612 Easterling The complex interplay of human activities and the global environment has been examined for over a decade with modeling schemes that focus on discrete problems that are decoupled from the complex whole (e.g., single sector studies, lack of feedbacks between component parts, partial representation of key relationships, poorly specified linkages between human and biophysical systems) thus making such schemes weak policy tools. Integrated assessments (IA) are needed to more completely model whole human-environment systems. Several IA efforts are under way, most of a highly spatially and sectorally aggregated form. Little attention has been given to the question of how much spatial and sectoral detail is necessary in order to achieve reliable estimates of land use and ecological changes in regional, national, and global modeling assessments; such is the question to which this proposed research is addressed. It is hypothesized that a spatial hierarchy of modeling is needed to present complex human-environmental systems. The research objectives here are: (1) to develop information linkage between the Century terrestrial ecosystem model and the FASOM economic model in order to assess changes in the human-environmental system of the U.S. Great Plains in response to climate changes; (2) to identify and quantify the critical human environmental factors controlling land use decisions at local and regional scales; and (3) to evaluate the sensitivity of the human-environmental system of the U. S. great Plains to local scale land use decisions relative the aggregated regional analysis.
