Antarctic sea ice breaks winter records

Sea ice around the Antarctic continent has continued to break winter records, while in the Arctic Ocean it melted to its sixth lowest extent, say scientists at the National Snow and Ice Data Centre (NSIDC).

Sea ice surrounding the Antarctic continent reached its maximum extent on 22nd September with an area of 20.11 million square kilometres, averaging 20 million square kilometres over the month.

At 1.54 million square kilometres above the 1981 to 2010 average extent – which is nearly four standard deviations above average – the new figure is record breaking.

This new record extent follows consecutive record winter maximum extents in 2012 and 2013, while sea ice in Antarctica has remained at satellite-era record high daily levels for most of 2014.

Reasons for the sea ice levels are unclear, but might be caused by changing wind patterns or recent ice sheet melt, according to lead scientist at NSIDC Ted Scambos. He said: “What we’re learning is, we have more to learn.”

Meanwhile, Arctic sea ice fell to the sixth lowest extent in the satellite record, both in the daily and monthly average. It hit 5.02 million square kilometres on 17th September and averaged 5.3 million square kilometres for the month.

NSIDC Director Mark Serreze said: “Twenty years ago, having ice extent this low would have astounded us. Now it is expected.”

The lowest Arctic extent on record occurred in 2012, when sea ice measured 3.41 million square kilometres. The succeeding lowest years are 2007, 2011, 2008 and 2010.

Weather conditions prevailing over the summer of 2014 were unremarkable. The one significant weather pattern over the summer was a larger than normal pressure gradient over the Laptev Sea that drove southerly winds, brought warmer air and helped drive sea ice northward.

NSIDC scientist Julienne Stroeve said: “The fact that minimum ice extent in 2013 and 2014 still fell so low despite ordinary weather suggests that the system has settled into the low trend.”

Photo credit: Alan Light/ CC BY 2.0

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