Initiation of ice ages by creep instability and surging of the East Antarctic ice sheet

Creep or shear heating instability is shown to be a plausible means of initiating a surge of the East Antarctic ice sheet and plunging the Earth into an ice age. The occurrence of this instability requires only that the ice thickness exceed a critical value which may not be much larger than the present ice dome thickness. Creep instability can occur on the fast time scale of 100-1,000 yr required by inferences of past rapid cooling events and sudden rises of sea level before the onset of Northern Hemisphere glaciations.