Ice core work on Greenland has produced dramatic evidence for an instability of the climate system in the North Atlantic sector. In this paper, climate modeling results indicate another possible example of a multiple equilibrium climate state, where such behavior might apply to the ice sheet itself. Although most CO 2 scenarios do not predict a collapse of the Greenland Ice Sheet in the future, results suggest that if it did, present boundary conditions may be sufficient to maintain Greenland in an ice-free environment even after the greenhouse effect has dissipated.