PROGRAM TITLE: Response of Vegetation to CO2 and Climate ACTIVITY STREAM: Processes, Modeling SCIENCE ELEMENT:Biogeochemical Dynamics, Ecological Systems/Dynamics DEPARTMENT OF ENERGY DESCRIPTION: Goal of this research is to understand and predict combined effects of altered climate and the increased concentration of CO2 on vegetation. Specific objectives are to understand how plants respond to these variables; the role of vegetation in the global carbon cycle; and feedbacks of the terrestrial biosphere on climate. Products derive from long term field experiments designed to evaluate the effects of systematic manipulations of atmospheric CO2 and climate on plant and ecosystem processes. The information is used to develop biophysical and ecosystem models for evaluating vegetation changes in relation to altered climate conditions, and the mechanisms of carbon sequestration by terrestrial ecosystems. This Program has pioneered the Free Air CO2 Enrichment Experiment (FACE) approach - a leading protocol for evaluating the effects of CO2 and climate change on crops and ecosystems in a consortium of worldwide experiments. DOE/FACE research provides engineering/scientific support to the consortium, which includes terrestrial "flagship" experiments adopted by IGBP/GCTE. The research is coordinated with USDA, EPRI. Research Centers in five countries are deploying this approach to produce field data on plant and ecological processes. Data on the combined influence of CO2 and climate factors on photosynthesis, transpiration, respiration, growth and other parameters are produced for native and crop species, and for selected ecosystems. STAKEHOLDERS: Results contribute to assessments of benefits or impacts of increasing greenhouse gases and climate change on ecosystems. Comprehensive assessments (e.g., domestic and IPCC) use scientific information produced by this research. Domestic (e.g., joint NSF, USDA and Forest Service research) and International Research programs (e.g., "flagship" experiments of the IGBP) have vital interests in both protocols and research results from FACE studies. A growing segment of scientists depends on experimental protocols and technical expertise developed and implemented by the DOE FACE Program. SHORT-TERM POLICY PAYOFFS: This Program produces scientific information on the "biological effects of global change" needed for short-term policy analysis. (1) Data and models are developed for evaluating ecological impacts and/or benefits of CO2 and climate change, including measures of ecosystem process and sustainability. (2) Products are applicable to IPCC assessments of ecological impact, and for examining the issue of missing carbon in terrestrial environments. (3) Critical information is provided for (a) making accurate estimates of future atmospheric CO2 concentration, (b) deriving mitigation offsets for CO2 as part of the U.S. Government Climate Change Mitigation Strategy. The research contributes scientific information for analyzing greenhouse gas policy issues of the Climate Change Treaty, and the atmospheric CO2 stabilization study of IPCC. PROGRAM CONTACT:Roger C. Dahlman, DOE, ER-74, Washington, DC 20585, 301-903-4951