The most dramatic loss of ice in recent years has been the decline of summer sea ice in the Arctic Ocean. Between 1953 and 2006, the area covered by sea ice in September shrunk by 7.8 percent per decade, more than three times as fast as the average rate simulated by climate models. Researchers were further stunned in the summer of 2007 when Arctic sea ice extent plummeted to the lowest level ever measured, more than 20 percent below the 2005 record. This decline is rapidly changing the geopolitics of the Arctic region, opening the Northwest Passage for the first time in recorded history and triggering a scramble among governments to claim large swaths of the potentially resource-rich Arctic sea floor.
Their figure on the decline of the Arctic Sea is really breathtaking.