The end of the Younger Dryas, about 11,500 years ago, was particularly abrupt. In Greenland, temperatures rose 18°F in a decade.These things really put the global warming hysteria in perspective.Around 8,200 years ago, however, a surprising event occurred. The 8.2 ka event, was first discovered in the Greenland ice core GISP2, where high-resolution analyses indicate that over two decades temperature cooled about 6°F in Greenland. The entire event lasted about 150 years and then temperatures warmed, returning to their previous levels.