Arctic sea ice, the floating ice sheet that covers most of the Arctic ocean, shrunk to its third-smallest extent ever, measuring only 4.9 million sq. km (1.9 sq. miles). The last four years (2007-2010) are the four smallest on record.
For the first time in modern history, the Northwest Passage and the Northern Sea Route were simultaneously ice-free in September.
Arctic ice shrinks every summer and grows every winter, but this summer, it shrunk at the fastest rate ever measured – more than 50 percent faster than average, and breaking the 1999 record.