If temperatures in the Antarctic are usually well below freezing, how can the ice be melting? Sure, in summer when temperatures are sometimes above zero you'll get a little surface melting, but it will re-freeze when temperatures go back below zero, which they do even in summer. And the kilometers of ice under the surface are completely unaffected by a little surface warmth.

Don't you think the most reasonable explanation for glacier calving is the weight of all the ice slowly sliding out to sea?