The Younger Dryas cold interval as viewed from central Greenland

Greenland ice-core records provide an exceptionally clear picture of many a spects of abrupt climate changes, and particularly of those associated with the Younger Dryas event, as reviewed here. Well-preserved. annual layers c an be counted confidently, with only approximate to 1% errors for the age o f the end of the Younger Dryas approximate to 11,.500 years before present. Ice-how corrections allow reconstruction of snow accumulation rates over t ens of thousands of years with little additional uncertainty. Glaciochemica l and particulate data record atmospheric-loading changes with little uncer tainty introduced by changes in snow accumulation. Confident paleothermomet ry is provided by site-specific calibrations using ice-isotopic ratios, bor ehole temperatures, and gas-isotopic ratios. Near-simultaneous changes in i ce-core paleoclimatic indicators of local, regional, and more-widespread cl imate conditions demonstrate that much of the Earth experienced abrupt clim ate changes synchronous with Greenland within thirty years or less. Post-Yo unger Dryas changes have not duplicated the size, extent and rapidity of th ese paleoclimatic changes. (C) 1999 Elsevier Science Ltd. All rights reserv ed.