Arctic sea ice hits minimum, 4th lowest since 1979: data centre
But in some places, such as northern Canada, thick ice converged and increased
Summer’s over: on Sept. 11, Arctic sea ice reached its minimum extent for 2015.
And, as the Colorado-based National Snow and Ice Data Center predicted earlier this month, the minimum Arctic sea ice extent ranks as the fourth lowest in the satellite record, which started in 1979.
This year’s shrinkage of Arctic sea ice “reinforces the long-term downward trend in Arctic ice extent,” the NSIDC said Sept. 15.
A map that the NSIDC generates from satellite data shows that clockwise wind patterns caused by “anticyclonic” atmospheric conditions have caused thick ice to converge in the Canadian Arctic Islands and an area north of Greenland, increasing ice thickness by up to 30 per cent.
That’s why sections of the Northwest Passage still have some ice.
But the Northern Sea Route north of Russia and most of the Beaufort and Chuckchi seas experienced high melt rates and are completely ice free.
“If this thicker ice were transported to areas of high melt rates (like that in the southern Beaufort), it would have an impact on summer ice coverage,” the NSIDC said.
Changing winds or late-season melt could still reduce the Arctic sea ice extent, as was the case in 2005 and 2010, the data centre said.
This year, the minimum extent was recorded four days earlier than during the 1981 to 2010 average, but came in behind 2012 (lowest), 2007 (second lowest), and 2011 (third lowest).
The route taken in 1906 by Norway’s polar explorer Roald Amundsen through the Northwest Passage remains open, while the deeper and wider Northwest Passage route through Parry Channel still has some ice in it.