The program is designed to assess, evaluate, and predict the ecological, environmental, and human health consequences of global change, including the interaction of plant and animal communities with the climate system. Additional supporting areas of research in the program include: assessment and research to develop techniques to mitigate and adapt to climate change; development of emission factors and chemical models to understand and describe the production, transport, and fate of radiatively important trace gases; and evaluation of the relationship between global climate change and changes in regional climate and air quality. The paper reviews the research agenda, with emphasis on the atmospheric chemistry and climatological aspects of the program.