Coupled Ocean-Atmosphere Simulation of the Last Glacial Maximum

S Rahmstorf (Potsdam Institute for Climate Impact Research, PO Box 601203, 14412 Potsdam, Germany.; A Ganopolski; V Petoukhov; M Claussen

We present a simulation of the climates of both the modern time and the last glacial maximum with a coupled ocean-atmosphere model of intermediate complexity. Driven by prescribed solar radiation and carbon dioxide levels and, for the glacial simulation, the presence of continental ice sheets, the model predicts the equilibrium climate of the Earth including its atmospheric and oceanic circulations, temperature distribution, sea ice cover and hydrological cycle. For the modern climate, the large-scale circulation and key climatic indicators are within the range simulated by current general circulation models. For the glacial climate, the model predicts a global annual cooling of 6 K. Changes in oceanic circulation and heat transport, particularly in the Atlantic, play an important role in glacial cooling.