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THERMOHALINE CIRCULATION; MODEL; 21ST-CENTURY
Abstract:
We investigate the effect of ice sheets on climate change under elevated atmospheric CO2 concentrations with an atmosphere ocean general circulation model ( AOGCM) coupled to a thermomechanical ice sheet model and a vegetation model. The effect of increased meltwater fluxes from ice sheets turned out to be negligible in the phase of initial weakening of the North Atlantic meridional overturning circulation ( AMOC), and more important during the recovery in subsequent centuries. Lower surface height of the Greenland ice sheet ( GRIS) leads locally to a warming, especially in winter, and remotely to a cooling over northern Eurasia due to modified atmospheric circulation. With quadrupling of the atmospheric CO2 concentration the entire GRIS is exposed to surface melt in summer. On formerly ice-covered grid points climate locally warms strongly via increased albedos, with positive feedbacks due to boreal forest expansion.
