The decline of sea ice has accelerated since 1996. The thinning of ice means less of ice cover and more open ocean as the ice packs are eaten away by the melt. Moreover, the nine lowest extents in the satellite era have all occurred in the last nine years.
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None of those historical facts proves anything in particular about this year’s ice minimum: they do, however, bring a bit of context to the NSIDC’s suggestion that there is something unusual about the northern sea routes being open just now.
“The marked energetic mixing we are seeing here at the heart of the Arctic ice-melt zone may prove key in understanding a potential new climate feedback”, Alford said.
After posting the smallest winter maximum on record earlier this year, Arctic sea ice has reached its summer minimum extent, which NASA and the NSIDC have logged as the the fourth lowest extent on record.
Dr Colin Summerhayes, emeritus associate at the Scott Polar Research Institute, said: “The latest Arctic data from the NSIDC confirm that 2015 has the fourth lowest area amount of sea ice”. Although 2014 saw the largest sea ice extent on record in the Southern Ocean, this year is showing a September extent that’s the second lowest in the past 10 years – with only 2008 showing a lower extent at this time of year. In September 2012, when the Arctic ice was at its lowest, it measured only 3.4 square kilometers. The lower ice levels in both seasons confirm predictions of scientists who have long argued that declining Arctic ice would constitute solid evidence that the Earth is warming.
Scientists warn that, by the time this month is over, sea ice cover in this corner of the world could shrink even further.
But it could change with any sudden shift in wind patterns or a late-season melt. “There might be some recoveries during some years, especially when the winter is unusually cold, but it is expected to go down again because the surface temperature in the region continues to increase”.
Frigid nights and the sun’s disappearance ensure the ice will begin to grow in the coming months.
“Historically, the Arctic had a thicker, more rigid sea ice that covered more of the Arctic basin, so it was difficult to tell whether El Niño had any effect on it”, said Richard Cullather, a climate modeler at Goddard. It sounds as though ice conditions that summer may not have been too dissimilar to this year.
Summer minimum sea ice has shrunk since satellites began measuring in 1979. The low was driven partially by an August storm, according to NASA.
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“Instead of using data like the sea ice minimum as a clear warning sign to take bold action”, Nicol continued, “our leaders are allowing Shell to drill for oil in the melting Arctic ice”.
