Sea-ice cover in the Arctic Ocean last week dropped to an annual minimum 5.02 million square kilometres, according to satellite observations by the National Snow and Ice Data Center in Boulder, Colorado.
This year’s minimum is the sixth lowest since satellite measurements began in 1979. Arctic sea-ice cover on 17 September was 1.61 million square kilometres higher than the record low extent observed in September 2012, but still 1.20 million square kilometres below the 1981–2010 average.
This year, a sliver of open water from the Laptev Sea off the coast Siberia extended the farthest north that open ocean has reached since the late 1970s.
Meanwhile, sea ice around Antarctica has exceeded the record maximum extent set last year. For the first time in the 35-year satellite era, Antarctic sea ice now covers more than 20 million square kilometres — an area almost the size of North America — and may still be growing.