Earth Planet. Sci. Lett. 337–338, 243–251 (2012)

The elevation of the interior of the ice sheet covering West Antarctica has not risen substantially over the past five million years, according to exposure ages collected near the ice sheet's divide.

Sujoy Mukhopadhyay of Harvard University and colleagues measured the accumulation of cosmogenic nuclides on bedrock surfaces along the escarpment that divides the West Antarctic ice sheet from the East Antarctic ice sheet. The exposure ages, along with the team's subsequent ice-sheet simulations, suggest that the ice there has been at or below its present elevation for much of the past five million years, with only brief highstands of less than 200 metres. The largest of such highstands occurred 11,000 years ago, with a maximum elevation gain of 110 metres. Intriguingly, during periods of warming over Antarctica, when precipitation and snow accumulation rates were higher, the elevation of the West Antarctic ice sheet was very similar to, or lower than, its present-day height.

The modelling suggests that higher accumulation was balanced by more pronounced melting of the ice-sheet's marine-based edges, which led to the thinning and collapse of these sectors.