This map is crap because it will take a hell of a lot more than 4C to melt Antarctica, that continent is frozen solid due to it covering the pole itself due to cutting off the water flow patterns.
also a whole lot of Antarctica is above 4,000ft above sea level which is cooler due to elevation as well.
The only cities we can ever hope to build in Antarctica will HAVE to be built underground where the temperature is more or less stable and above freezing.
Also they don't take into account all the extra water evaporation that will take place due to temp rise which will lead to greener tropics instead of more deserts...
Deserts reign during ICE AGES, because the decrease in temp leads to LESS water for rain in the atmosphere...