An item in the news today caught my attention: Antarctic Lakes. In the title there is the suggestion that there are 145 of them and counting, but in the text the estimates go as high as 500 such lakes, though going by the text it would seem no one is at all sure what the upper limit would be. It would seem to be the case that two lakes might merge to become one lake and lower the number of lakes and yet raise the surface area and volume the water occupies under the thick ice sheet. My concern is to do with the whereabouts of all these lakes in terms of depth and spread. I am ignoring the age they think the ice sheet is, and whether or not it is metabolically alive.
It seems to me that if the geothermal heat input exceeds heat loss to the atmosphere in the long term, then these lakes will grow in surface area and volume. If they are at around the same depth and if they are biased, or non-randomly spread underneath the ice, then there is the possibility of a structural weakness developing deep beneath the surface of the ice sheet. It seems to me that the icecap or large areas of it could be resting on many ice columns, and if the distribution of force of the ice sheet lends itself to a slippage then there could be quite a change in sea level - OK a worst case scenario, but it is worth thinking about if you live in low-lying places. My real estate economic advice: buy high and sell low :-)