#aFactADay2026
#1829: the last glacial maximum, when much of the world was frozen and thus lots of the water was frozen in ice sheets, was about 22 thousand years ago. the ice extended from the top of Greenland to what is now the continental US - the Great Lakes were thought to be formed by the retreat of the Wisconsin glacier about 10-12kyBP. the sheet covering North America in up to 3.2km of ice is called the Laurentide ice sheet, which was so massive (its area is measured in MILLIONS of square miles) that it pretty much dictated the global climate.
since the last glacial maximum, the global sea level has risen drastically. i've seen quite different numbers for exactly how much, but roughly 110-130m in that 22 thousand years. even in the last 5ky there's been a reasonably large rise of about 5m. this has wildly changed the coastline - i was aware of Doggerland, the big bit of land between what's now England, France and Germany that disappeared about 10-8kyBP, but now i'm reading about it in the context of the Floridan peninsula, which has more than halved in area since the last glacial maximum.