A Kiwi climate scientist says he's been alarmed at how much sea
ice the planet's poles lost in 2016, in what was one of the hottest
years on record.
Dr James Renwick of Victoria University has been
tracking levels of sea ice in the Arctic and Antarctica, where, as 2017
dawned, more than one million square kilometres of ice was missing when
compared with the historical average.
Renwick said sea ice
extent had been more than two million square kilometres below normal
every day since September 1, according to the Sea Ice Index published by
the US-based National Snow and Ice Data Centre.
Over a 76-day stretch between October 13 and December 27, more than three million square kilometres of ice were missing.
Although
overall ice extent had been below average at both poles, the picture in
the Arctic has been much clearer and more dramatic over time.
There, the rate of loss was much more rapid - it now had 40 per cent less ice in late summer than it did in the 1980s.
Meanwhile, Antarctica overall saw around 4 per cent more sea ice in winter, up to 2014.
In
the past two years, however, sea ice has been in decline around the
frozen continent, with the extent falling to record lows in the last few
months of the year.
In the Northern Hemisphere, the sea extent
had been close to record low levels on most days in 2016, and, as winter
advanced, ice extent decreased three separate times at a time ice
should have been growing.
"So, after the sun went down and the
Arctic ocean became dark and cold, even then, sea ice managed to melt,
which is pretty remarkable."
http://www.nzherald.co.nz/environment/news/article.cfm?c_id=39&objectid=11776133
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