Keith (Southend) wrote:

Graham P Davis wrote:

My forecast three months ago of a record low has come good - or bad,
depending how you look at it - and the next challenge is to say when the
Arctic ice will disappear completely during the summer. The most
pessimistic forecast I've seen is that it will happen by 2040. However,
my feeling is that that's still too optimistic. The graph at
http://arctic.atmos.uiuc.edu/cryosph...rrent.anom.jpg shows an
accelerating decline. Also, the 40% loss in ice-thickness reported a
while ago was for the period 1965-95. As global temperatures had not
started falling until about 1975, I presume the 40% loss occurred after
that year. 40% loss in twenty years and it's been getting warmer since
then! Most of the rough (very!) calculations I've made come up with 2020
as the likely year when the ice goes. The next challenge is to be sure to
live long enough to see it!


That is quite a scary concept.

The latest from UIUC yesterday (http://arctic.atmos.uiuc.edu/cryosphere/) is
that the area is now down to 3.22 million sq. kilometres.

NSIDC (http://nsidc.org/news/press/2007_sea...810_index.html)
has also been updated and has interesting information on the North-West
Passage. One niggle I'd have with it though is it says "the region is more
open than it has ever been since the advent of routine monitoring in 1972."
Actually, it's been monitored for longer than that. In the late 60s and
early seventies it was monitored using satellite data and through that
period and earlier there were aircraft recce flights over the area. The Met
Office published charts from 1959 onwards and, although data-coverage is a
bit sketchy in the early years, it is still sufficient for me to say that
the passage is more open than in any year since those publications began.

On the same page, there is an animation of the disappearance of old ice from
1982-2007. It was my estimate that there'd been a stronger than average
outflow of old ice from the Arctic during the winter and spring that led me
to expect that this summer would see a record minimum in Arctic sea-ice
coverage.

--
Graham P Davis
Bracknell, Berks., UK
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