Patagonian Ice Sheet shaped regional climate during the Last Glacial Maximum

During the Last Glacial Maximum, changes in the thickness of the Patagonian Ice Sheet modified southern Andean topography. However, the resulting atmospheric feedbacks remain poorly constrained. Using an atmosphere–land coupled model, we isolated the climate response to prescribed ice-sheet thicknesses. Our results indicate that a thicker ice sheet generates a decrease in low level zonal winds, a westward shift in precipitation, a temperature increase along the western margin of Eastern Patagonia, and an increase in storm activity over Patagonia. A decrease in thickness generates the opposite pattern. Our findings suggest that the Patagonian Ice Sheet not only responded to climate change, but also actively modulated it—highlighting the role of topographic forcing in shaping atmospheric circulation over the Southern Hemisphere mid-latitudes.