Abstract ATM-9631282 Overpeck, Jonathan T. University of Colorado Title: Climate Change of the Last 500 Years: Simulations Versus Data This award will support the scientific coordination needed to complete a 500-site global database of annually-dated time paleoclimate time series, and document it sufficiently for broad usage by the entire global change community. This database will be used to map the spatio-temporal patterns of climatic variation over the past 500 years, and thus provide the first comprehensive view of pre-anthropogenic interannual to interdecadal climate variability. The project will coordinate the use of data and theory to produce new timwe series of hypothesized volcanic, solar, trace-gas, tropospheric aerosol, land-use, thermohaline and ENSO climate forcing over the past 400 years. These time series of forcing will then be used as input to a suite of transient climate model experiments using state-of-the-art 3-D atmospheric and coupled atmosphere-ocean models developed at NASA GISS. The simulated responses to the various hypothesized forcing will be compared to the spatio-temporal patterns of change mapped out using the database. This will make significant reductions in the uncertainty regarding the nature and causes (natural and anthropogenic) of interannual to century-scale climate variability.
