Abrupt climate shifts in Greenland due to displacements of the sea ice edge, Geophys

An atmospheric circulation model is used to show that small reductions in sea ice extent in the North Atlantic are capable of explaining the abrupt changes in temperature, snow accumulation and oxygen isotopes recorded in Green-land during the Dansgaard-Oeschger (D-O) events of the last glacial period. Model simulations indicate that reduced sea ice cover in this region produces warming that is especially pronounced in winter and an accumulation increase that occurs primarily in summer. Mechanisms for driving such displacements of sea ice could be small changes in ocean thermohaline circulation (OTC) or rearrangements of the tropical atmosphere-ocean system. 1 The Dansgaard-Oeschger (D-O) events that punctuated the last glacial period (50–10 kyr BP) are abrupt warming episodes recorded in Greenland ice cores (1). Each event is charac-terized by a large temperature rise (7–10 C) over several decades, with the warm conditions lasting for 200–600 years before a more gradual return to the glacial state (2). Recent studies have found that the warming in Greenland is coincident with abrupt changes in other parts of th