The downward linear trend in October sea ice extent over the 45-year satellite record is 80,400 square kilometers (31,000 square miles) per year, or 9.6 percent per decade relative to the 1981 to 2010 average. Based on the linear trend, since 1979 October has lost 3.46 million square kilometers (1.34 million square miles). This equivalent to about twice the size of the state of Alaska.
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