The Antarctic ice mass, being about 2 1/2 miles thick, is pressing the land down underneath it by almost 1/2 mile. It has a large affect on the earth's gravitational pull - the ocean level below the earth's equator is significantly higher than it is at the same latitude north.
There is a mountain in Ecuador called Mount Chimborazo that is closer to space than Mount Everest.
The 'Highest' Spot on Earth? : Krulwich Wonders... : NPR
If/when Antarctica ice melts, then the ocean level - eventually - will rise much more in the northern hemisphere, because the gravitational shift that results from the loss of the mass of all that ice.
This change cannot but help having an effect on plate tectonics, as well.
Greenland and all other large land masses - like mountain ranges - have similar proportional gravitational effects.