The Laurentide Ice Sheet, a gigantic glacier that reaches up to 3 km in thickness in central-northern Canada, is rapidly melting and letting out, from beneath, the waters of Lake Agassiz, a huge lake of 163,000 cubic km (twice the size of the Caspian Sea) formed after the end of the Wurz glaciation in the Great Lakes area; the introduction of fresh water into the Atlantic (from 5 to 10 sverdrups at peak, 1 sverdrup = 1 million m3/s) causes a drop in temperature in the Northern Hemisphere of 5 degrees for 200 years.
