It can be easy to overlook the monstrous scale of the Antarctic ice sheet. Ice, thick enough in many places to bury mountains, covers a continent roughly the size of the US and Mexico combined. If it were all to melt, as it has in the past, global sea levels would rise by 58 metres. While this scenario is unlikely, Antarctica is so massive that just a small fraction of this ice melting would be enough to displace hundreds of millions of people who live by the coast.