New low for winter Arctic sea ice cover - tied with 2005
Arctic sea ice continues to decline, as new
data from the NOAA National Snow and Ice Data Centre shows. The
extent of winter sea ice cover is at a record low - tied with
2005.
The amount of Arctic sea ice has been declining at around 13%
per decade since satellite records began in 1979, in response
to factors associated with global warming. The rate of warming in
the Arctic is around twice as fast as the rest of the globe,
partially as a result of this
loss of sea ice. This is because ice counters regional warming
by reflecting heat, therefore loss of ice reduces the ability to
reflect heat, causing additional regional warming.
The declining trend in Arctic sea ice is complicated by a
seasonal cycle in ice extent. Arctic sea ice grows in the cold
winter months and retreats in the warmer summer months. This means
that the area covered by Arctic sea ice alternates between
extensive winter coverage, reaching a peak in February/March, and
limited summer coverage.
However, this seasonal pattern takes place in the context of an
overall declining trend in Arctic sea ice coverage. This year,
winter ice coverage has reached a new low, with the US National
Snow and Ice Data Centre reporting:
Sea ice extent averaged over the month
of February 2011 was 14.36 million square kilometers (5.54 million
square miles). This was a tie with the previous record low for the
month, set in 2005. February ice extent remained below normal in
both the Atlantic and Pacific sectors, particularly in the Labrador
Sea and the Gulf of St. Lawrence.
The
2007 IPCC report predicted that summer Arctic sea ice is likely
to disappear altogether by the end of the 21st century. However,
recent summer melting of Arctic sea ice has been even more
extensive than predicted in the IPCC report, leading to recent predictions
of ice-free summer seas in the Arctic within decades.
3.10pm - Updated with some extra information from the
NSIDC.