THE INFLUENCE OF VEGETATION-ATMOSPHERE-OCEAN INTERACTION ON CLIMATE DURING THE MIDHOLOCENE

Simulations with a synchronously coupled atmosphere-ocean-vegetation m odel show that changes in vegetation cover during the mid-Holocene, so me 6000 years ago, modify and amplify the climate system response to a n enhanced seasonal cycle of solar insolation in the Northern Hemisphe re both directly (primarily through the changes in surface albedo) and indirectly (through changes in oceanic temperature, sea-ice cover, an d oceanic circulation). The model results indicate strong synergistic effects of changes in vegetation cover, ocean temperature, and sea ice at boreal latitudes, but in the subtropics, the atmosphere-vegetation feedback is most important. Moreover, a reduction of the thermohaline circulation in the Atlantic Ocean leads to a warming of the Southern Hemisphere.