PROGRAM TITLE: Arctic System Science (ARCSS) ACTIVITY STREAM: Process, Model SCIENCE ELEMENTS:Climate and Hydrological Systems, Biogeochemical Dynamics; Ecological Systems and Dynamics; Earth System History; Human Interactions NATIONAL SCIENCE FOUNDATION SCIENTIFIC MERIT: ARCSS is an interdisciplinary program, the goal of which is to understand the physical, geological, chemical, biological, and social processes of the arctic system that interact with the total Earth System and thus contribute to or are influenced by global change. ARCSS is predicated upon the expectation that the greenhouse effect will be greater in high latitudes and that direct human impacts are increasing in the Arctic. ARCSS has four linked ongoing projects: Greenland Ice Sheet Program (GISP2), Paleoclimate of Arctic Lakes and Estuaries (PALE), Ocean/Atmosphere/Ice Interactions (OAII), and Land/Atmosphere/Ice Interactions (LAII). Science steering committees and panels facilitate science integration and produce periodic reports and recommendations. GISP2 has completed a five-year drilling program and has retrieved a 3052 meter long ice-core which contains a detailed 250,000 year record of climate and atmospheric constituents. PALE reconstructs a paleoecological history from the sediment record of arctic and subarctic bogs, lakes, and near ocean sediments. Other historical studies such as archeology are planned. OAII investigates the effects of energy exchange on the water-column structure of the Arctic Ocean and interactions with the overlying atmosphere. Carbon sequestration, ecosystem dynamics, sedimentation and carbon deposition are also important topics in these large-scale investigations. OAII activities include the 1994 joint US/Canadian cruise across the Arctic Ocean to examine climatological and biological interactions and a major new project called Surface Heat Budget for the Arctic Ocean (SHEBA). LAII investigates feedback processes within the arctic system which amplify global climate change, climate variability and the fluxes of ice, fresh water, water-borne materials; and greenhouse gases. The initial focus will be on measurement, and experiments concerning the dynamics, and modeling of regional gas fluxes. In the future, ARCSS will incorporate synthesis, integration and assessment activities. A program on human/environmental Interactions to address issues of system sustainability will be developed. STAKEHOLDERS: ARCSS is an integral part of the U.S. Global Change Research Program. ARCSS is coordinated by four NSF offices and its findings contribute to many of the other NSF Global Change initiatives, for example WEAVE (Water and Energy: Atmospheric, Vegetative and Earth Interactions), ESH (Earth System History), GCTP (Global Tropospheric Chemistry Program), WOCE (World Ocean Circulation Experiment), GLOBEC (Global Ocean Ecosystems Dynamics), EROC (Ecological Rates of Change), and LMER (Land-Margins Ecosystems Research). ARCSS is coordinated with other U.S. agencies through the Interagency Arctic Research Policy Committee (IARPC). ARCSS interacts internationally with several ongoing activities. GISP2 interacts closely with the European Greenland Ice Core Project. ARCSS also has direct connections to several IGBP core projects, for example GISP2 and PALE link with PAGES (Past Global Changes), OAII links to LOICZ (Land-Ocean Interactions in the Coastal Zone) and JGOFS (Joint Global Ocean Flux Study), and LAII links to BAHC (Biospheric Aspects of the Hydrologic Cycle) and GCTE (Global Change and Terrestrial Ecosystems). POLICY RELEVANCE: ARCSS seeks to advance the scientific basis for predicting environmental change on a decade to centuries time scale and for formulating policy options in response to the anticipated impacts on humans and social systems. Short term payoffs from the paleo projects, such as evidence of rapid rates of temperature change implied by the analysis of the GISP2 core provide new understanding of other paleoclimate data. Longer- term payoffs will come from the modeling and synthesis efforts of OAII and LAII to predict the impact of global change and feedback on land and ocean conditions, use, and management. PROGRAM CONTACT:Patrick J. Webber, ARCSS Program Director