An examination of the temperature and CO2 record back to 45 million years indicates that CO2 levels above 400 ppm will not allow the continued existence of the Antarctic ice shelves. The loss of those shelves, even without a catastrophic collapse of the WAIS, will facilitate an enormous movement of land-based glacial ice into the seas raising global sea level by tens of feet.
Our Atmospheric CO2 is now past the point that in the Deep Past has Meant the Melting of the Antarctic Ice Sheets
Ann Arbor (Informed Comment) - So as a historian, I am particularly interested in what the past tells us about the present. I've taught courses on climate change in history. But of course my kind of history doesn't go back very far from the point of view of physical scientists. The academic...