Video: Arctic sea ice is in long term decline – so is it foolish to predict ice-free summers?
- 08 Feb 2011, 12:57
The climate youtube site "Crock of the Week" had turned its
attention to US ex-astronaut and climate sceptic Harrison Schmitt.
Schmitt claims that environmentalists are modern-day communists and
that Arctic sea ice is currently recovering.
The UK's home-grown climate sceptics have made similar claims -
with respect to the sea ice at least.
Dr David Whitehouse, science editor of the climate sceptic
thinktank The Global Warming Policy
argued in the Telegraph last April that the Arctic sea ice is
not in decline, but is recovering:
"it does seem that the sea ice is
returning to 'average' after the record lows of 2007 and 2008.
There has been a definite recovery trend since then so far from
being a progression towards ice free summers it seems that it was a
temporary dip. The recent observations do make the 2007 projections
that the region would be ice free by 2013 look very unrealistic.
Given what is happening only the foolish would look many
years into the future and predict ice free summers
In the video, the views of Rear
Admiral David Titley, a US Navy meteorologist, chime with the
scientific consensus that the Arctic sea ice is in long-term
"we expect to
see about four weeks of basically ice free conditions in the Arctic
by the mid-to-late 2030's. By the middle of the century,
we could be seeing quite easily two to three months of ice free
The National Snow and Ice Data Center - the US body that
measures Arctic sea ice - writes in their FAQ,
(last updated October 2009)
Sea ice extent normally varies from year
to year, much like the weather changes from day to day. But just as
one warm day in October does not negate a cooling trend toward
winter, a slight annual gain in sea ice extent over a record low
does not negate the long-term decline.
Like with temperature changes, scientists understand changes in
Arctic sea ice on the basis of long-term trends, rather than
short-term changes. The level fluctuates from year to year because
of local weather and regional climate patterns so it is only by
looking at the trend over several decades or more that the true
pattern emerges. The NSIDC write:
Although the 2009 sea ice minimum was
larger than the past two years, the rate of decline since 1979
increased to -11.2 percent per decade … sea ice in the Arctic is in
decline in all months and the decline is greater and the rate
faster than natural causes could account for.