Ice Thickness of Antarctica: The ice layer averages about 1 mile (1.6 kilometers) thick, but reaches up to 3 to 4 miles (nearly 5 kilometers) deep in certain areas.

 So, I don't think the ice 3 to 4 miles deep on Antarctica is going to melt this century yet. However, it might melt in the coming centuries and open Antarctica for colonization from all over the world.

Since the heat in the equatorial regions will become during summers unbearable for humans they might go underground during the day and only come out at night when it is cooler. Humans are pretty adaptable but the heat always kills way more humans than the cold (which is interesting too).

The reason this is true is that when you lose your bearings from heat prostration, unless someone is there to save you and take you to a hospital or something you are just dead.

Whereas if you are freezing and cold if you can just build a fire often you can survive really cold temperatures even if you are inside of an igloo somewhere. As long as you keep where you are below 50 degrees with a little fire inside of the igloo  you won't melt the igloo.

So, in the heat the only relief is usually going underground and digging down to where it is cooler there and then airing that place out during the nights when the air is cooler.

So, for this reason humans do better in really cold places than they do in really hot places.