The world is deep in a period of glaciation. 5 million AD, the planet is once again dominated by icecaps, as it was in the Pleistocene epoch, 2 million BC. So much water is locked up in the icecaps that global sea levels are nearly 500 feet (about 150 meters) lower than they were during the Holocene. Ice sheets over a kilometer thick cover most of North America and the whole of Scandinavia, reaching down into Northern Europe.