9311593 Dietz This is a project designed to develop an improved model for studying the environmental impacts associated with trends in population, affluence, and technology. Each portion of the simple equation often used to assess environmental impacts (I=PAT) will be reformulated to reflect added complexity, and then time series, cross- sectional, and pooled time series cross-sectional data from a variety of nations will be used to estimate new models incorporating these changes. This project has the potential to make important contributions not only to our theoretical understanding of the sources of environmental problems, but also to environmental policy. Previous work using the I=PAT model has been hindered by the oversimplified and unrealistic nature of the variables used and the relationships assumed to exist among them, thus making it impossible to use this model to accurately study and forecast environmental trends. To the extent that this project is successful, it will overcome these difficulties. ***