PROGRAM TITLE: Effects of Global Changes on Agroecosystems ACTIVITY STREAMS: Processes, Assessments, Model/Predict SCIENCE ELEMENT:Ecological Systems and Dynamics BUDGET LINE ITEMS: EPA, ORD, Stratospheric Modification, GlobalÊClimate;ÊEPA, ORD, Stratospheric Modification, Stratospheric Ozone U.S. ENVIRONMENTAL PROTECTION AGENCY OFFICE OF RESEARCH AND DEVELOPMENT SCIENTIFIC MERIT: Determine: (1) the probable magnitudes and rates of human-induced change in ecological systems; (2) how these changes can be distinguished from natural fluctuations; and (3) which ecological systems and species are changes most likely to affected and what attributes of importance to humans will be at risk. The objective of this research is to develop risk characterizations of the consequences of global change for the world's most important crops. Specific questions addressed include: 1) How sensitive are crop productivity and cropping systems to UV-B radiation, increased CO2 and temperature, and changing precipitation patterns on a regional basis? 2) What is the global flux of methane emissions from rice fields? 3) What options can be identified to minimize methane emissions without reducing rice yields. The focus will be on key global crops. Initially, the irrigated rice cropping system is emphasized. The research is being conducted at the International Rice Research Institute (IRRI) in the Philippines, with further collaboration with leading rice research groups in Japan, Korea, China, Malaysia, India, Philippines, United States and Europe. It includes experimental field and laboratory studies and modeling studies, primarily based on ORYAZA1, a physiological simulation model, and ecosystem models which integrate the responses of rice and components of the rice cropping system to integrate and extrapolate the results to the regional level. This research will characterize on regional and global scales the risks to rice productivity from stratospheric ozone depletion and climate change. STAKEHOLDERS: Partnerships are in place with researchers in 6 Asian countries and the International Rice Research Institute. Research is coordinated with IGBP/GCTE. Collaboration has also occurred with the USDA/ARS, NCAR, and scientists at several major U.S. universities. POLICY RELEVANCE: Contributes to the 1995 and subsequent IPCC Assessments as well as the following major milestones in the U.S. GCRP: PROCESS STUDIES; Ecological Systems, Species Responses, 1991-1995 Milestones: Physiological sensitivity to climatic variability established for selected economically important species, and Sensitivity of selected rice cultivars to UV-B established; 1996-2000 Milestones: Physiological sensitivity of economically important species to climatic variability continued, and Sensitivity of rice yields to increased UV-B modeled globally; MODELING; Greenhouse Gases, 1996-2000 Milestone: Dynamic global carbon models developed; Economics and Other Human Systems, 1996-2000 Milestone: Models relating agricultural activity to environmental conditions refined and expanded; ASSESSMENT; 1996-2000 Milestone: Integrated international assessments of global change continued. PROGRAM CONTACT:Peter Beedlow, U.S. EPA, 200 SW 35th St, Corvallis, OR 97333 (503) 754-4634