According to the analysis of the migration patterns of the bowhead whale ( balaena mysticetus ), the Northwest Passage was blocked to such an extent for the past roughly 3000 years that bowhead whales were not able to pass through it.

Global warming has, however, opened the Northwest Passage during the last few weeks.

This map from the National Snow and Ice Center (NSIC), USA from 9 Sep 2007 shows the present region covered by ice, and the average (median) limit of ice in September during 1979-2000 as a pink (magenta) line. The route from the north of the Atlantic Ocean, going between Canada and the ice around the North Pole, through to the north of the Pacific Ocean and then to East Asia, is clearly open.

Analysis of images from the Envisat satellite of the European Space Agency show that the ice-covered region in the Arctic is presently about 3 million square km, which is about 33% less than what it was a year ago, in the summer of 2006, when it was about 4 million sq.km. During the last 10 years, the annual reduction was “only” about 100 thousand sq.km. This is considered a dramatic acceleration in the loss of Arctic ice in comparison to scientists’ conservative predictions about the effects of global warming.