Stability of ice-age ice sheets

The stability of large ice sheets is investigated by using the present-day theory of the flow of ice in glaciers and ice sheets. The type of instability considered is that first mentioned by Bodvarsson. It is concluded that a small Arctic ice cap can become unstable and expand into a large ice age ice sheet as a result of moderate changes in the regime of the ice cap. A large continental ice sheet can also become unstable and shrink to nothing if the snow accumulation is reduced or the ablation rate increased. The results obtained fit well into the Ewing-Donn theory of ice ages. There is the possibility that the inherent instability of ice age ice sheets is in itself sufficient to explain both the formation and the disappearance of these ice sheets.