Ice sheets without dynamic topography

Dynamic topography results in uplift and subsidence events on Earth's surface with amplitudes on the order of a kilometer. These vertical motions are known to have influenced ice sheet evolution, but how dynamic topography has controlled the current state of present ice sheets is unknown. Here, we explore this by running ice sheet models to their equilibrium state after removing present-day dynamic topography. We find that Antarctic ice cover is significantly different without dynamic topography; in our optimal dynamic topography model, the ice mass (grounded area) in Marie Byrd Land decreases by 58% (55%), while the ice mass (grounded area) in the Weddell Sea increases 55% (77%). In Greenland, we see ice loss in the east and, in our optimal dynamic topography model, large sectors of the ice sheet become marine-based. Taken together, these findings indicate that dynamic topography plays a major role in the equilibrium geometries of ice sheets.