Liquid water under the ice shield could accelerate ice flows into the ocean

There are at least 145 lakes buried under kilometers of Antarctic Ice. Far from being isolated from each other, the lakes now appear to be connected by subglacial rivers and have a bearing on the movement of ice sheets. There can even be lakes sloping down mountains and uphill waterfalls.

(Gabrielle Walker“Hidden Antarctica: Terra incognita: deep under the ice continent is a world no one expected”, New Scientist, Vol 2580, 2 December 2006 pp30-35)