The U.S. Environmental Protection Agency, Office of Research and Development (ORD), is initiating a Global Climate Change Program to evaluate the potential environmental effects of climate change. The document describes one project, Effects of Global Climate Change on Agroecosystems, which will be administered at the EPA Environmental Research Laboratory-Corvallis as part of the ORD program. The document describes the areas in which research will be undertaken in the project over the next five years. The document presents the scientific questions that must be addressed in order to answer important public policy needs concerning the potential environmental effects of global climate change on agroecosystems and it describes the general research approaches that will be used to answer the scientific questions.