Arctic sea ice reaches record minimum

Every year Arctic sea ice extent grows during the winter months and shrinks during the summer months. At the end of the summer melt season, usually in September, the sea ice reaches a minimum.

This summer saw an unprecedented rates of loss, with large portions of the Arctic opening up that were previously covered by perennial (permanent) sea ice. The Northwest Passage—the sea route across the Arctic Ocean along the northern coast of North America—has opened as a consequence, and several small islands have been discovered.

Contributing to the record losses this year were unusually clear skies in the Arctic during June and July, and high-pressure patterns bringing warm air into the Arctic. The dramatic loss of ice cover this season is also the result of longer-term trends and processes in effect since the 1970s and before.

Global warming is a primary driver of the climate change in the Arctic. Warmer global temperatures caused by greenhouse gasses have accelerated the melting process. The melting process itself is enhanced by the ice-albedo feedback effect—surfaces covered by ice are replaced by open water, which absorbs more solar radiation, which in turn causes warmer global temperatures.