Arctic ice extent melt, 1979 - 2014
Seasonal land and ocean temperature fluctuations directly affect the amount of ice in the Arctic: Warmer temperatures in the summer melt arctic ice, and it freezes again in the winter.
Arctic ice is typically at its maximum extent in March and its minimum in September. The National Snow and Ice Data Center (NSIDC) has found that, in many years since it began tracking the ice extent in 1979, the Arctic has been unable to regain in the winter the ice it lost in the melt season.
Monthly levels of ice extent, 1979 to 2015, in millions of square kilometers
Arctic sea-ice extent has experienced an unmistakable downward trend in every single month since 1979.
In February 2015, arctic ice reached its maximum extent for the year. Not only did the maximum occur a month earlier than usual, but it was the lowest extent on record. Researchers at the NSIDC attribute this record-low maximum to atypical weather patterns in February that warmed the Pacific side of the Arctic.
SOURCE: National Snow and Ice Data Center.