Arctic sea ice reached its lowest annual extent�the absolute minimum�on September 15, 2007. This image is a composite image taken by the MODIS satellite on September 15 and 16, 2007, during a relatively clear-sky period. The Northwest Passage, through the channels of the Canadian Archpelago at bottom left, opened for the first time in human memory, this melt season. The Northern Sea Route, to the right around the coast of Siberia, remained blocked by a large mass of ice. Credit: NSIDC