March 24, 2017
Arctic sea ice reaches record low for third year in a row
Winter is coming to an end in the Arctic, with sea ice reaching its maximum extent as it does every year. The problem is that maximum extent is becoming less and less decade on decade, and March just marked the lowest annual coverage since records began.
Coverage was measured at 5.6 million square miles (14.4 million square kilometers) - the least since satellite examination of coverage started, almost four decades ago, according to NASA and the National Snow and Ice Data Center (NSIDC) in Boulder, Colorado.Maximum ice coverage has fallen each decade since the 1970s, at an average of 2.8 percent. The figures are even worse for minimum extent, which is falling at a rate of 13.5 percent.
The extent to which global warming is a cause is not certain, however, the scientific community is generally under the consensus that climate change caused by humans is largely responsible.
Earth's northern cap has warmed more than any other part of the globe over the past three decades, according to NSIDC scientists.
As well as covering a smaller area, Arctic ice is becoming thinner. This means that the sea, winds and higher temperatures have a more destructive effect.
A confusing picture
Maximum and minimum sea ice coverage has fallen to record lows in both the Arctic and the Antarctic this year. While the maximum extent in the Arctic was being noted at its lowest since records began, record lows were being observed for the Antarctic's summer minimum.
However, the Antarctic measurements are disappointing coming two years after a series of monthly record highs for sea ice coverage. Counterintuitively, those higher figures were indirectly caused by global warming through greater snowfall.
Higher temperatures cause more moisture in the air, which in turn leads to greater precipitation.
"There's a lot of year-to-year variability in both Arctic and Antarctic sea ice, but overall, until last year, the trends in the Antarctic for every single month were more sea ice," said Claire Parkinson, a senior sea ice researcher at NASA's Goddard Space Flight Center.
"Last year was stunningly different, with prominent sea ice decreases in the Antarctic. To think that now the Antarctic sea ice extent is actually reaching a record minimum — that's definitely of interest."
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