"john fernbach" wrote in message
oups.com...
I think it's okay to download this and print it out from the NCAR
website, for people who are too lazy to check out the hyperlinks.

Was it Nirvana who sang, "It's the end of the world, and I feel
fine"? Or am I thinking of some other group?

"It's the End of the World as We Know It (and I Feel Fine)" by R.E.M.
It's the only understandable line in the whole song.




QUOTE:
" The study indicates that, because of the disparity between the
computer models and actual observations, the shrinking of summertime
ice is about 30 years ahead of the climate model projections. "
--------------------------------------------------------------------------------------------------------------------------------------------------------------------


News Release

UCAR Communications


Arctic Ice Retreating More Quickly Than Computer Models Project
April 30, 2007

BOULDER-Arctic sea ice is melting at a significantly faster rate than
projected by even the most advanced computer models, a new study
concludes. The research, by scientists at the National Center for
Atmospheric Research (NCAR) and the University of Colorado's National
Snow and Ice Data Center (NSIDC), shows that the Arctic's ice cover is
retreating more rapidly than estimated by any of the 18 computer
models used by the Intergovernmental Panel on Climate Change (IPCC) in
preparing its 2007 assessments.


The study, "Arctic Sea Ice Decline: Faster Than Forecast?" will appear
tomorrow in the online edition of Geophysical Research Letters. It was
led by Julienne Stroeve of the NSIDC and funded by the National
Science Foundation, which is NCAR's principal sponsor, and by NASA.

"While the ice is disappearing faster than the computer models
indicate, both observations and the models point in the same
direction: the Arctic is losing ice at an increasingly rapid pace and
the impact of greenhouse gases is growing," says NCAR scientist Marika
Holland, one of the study's co-authors.

The authors compared model simulations of past climate with
observations by satellites and other instruments. They found that, on
average, the models simulated a loss in September ice cover of 2.5
percent per decade from 1953 to 2006. The fastest rate of September
retreat in any individual model was 5.4 percent per decade. (September
marks the yearly minimum of sea ice in the Arctic.)

But newly available data sets, blending early aircraft and ship
reports with more recent satellite measurements that are considered
more reliable than the earlier records, show that the September ice
actually declined at a rate of about 7.8 percent per decade during the
1953-2006 period.

"This suggests that current model projections may in fact provide a
conservative estimate of future Arctic change, and that the summer
Arctic sea ice may disappear considerably earlier than IPCC
projections," says Stroeve.

Thirty years ahead of schedule

The study indicates that, because of the disparity between the
computer models and actual observations, the shrinking of summertime
ice is about 30 years ahead of the climate model projections. As a
result, the Arctic could be seasonally free of sea ice earlier than
the IPCC- projected timeframe of any time from 2050 to well beyond
2100.

The authors speculate that the computer models may fail to capture the
full impact of increased carbon dioxide and other greenhouse gases in
the atmosphere. Whereas the models indicate that about half of the ice
loss from 1979 to 2006 was due to increased greenhouse gases, and the
other half due to natural variations in the climate system, the new
study indicates that greenhouse gases may be playing a significantly
greater role.

There are a number of factors that may lead to the low rates of
simulated sea ice loss. Several models overestimate the thickness of
the present-day sea ice and the models may also fail to fully capture
changes in atmospheric and oceanic circulation that transport heat to
polar regions.

March ice

Although the loss of ice for March is far less dramatic than the
September loss, the models underestimate it by a wide margin as well.
The study concludes that the actual rate of sea ice loss in March,
which averaged about 1.8 percent per decade in the 1953 -2006 period,
was three times larger than the mean from the computer models. March
is typically the month when Arctic sea ice is at its most extensive.

The Arctic is especially sensitive to climate change partly because
regions of sea ice, which reflect sunlight back into space and provide
a cooling impact, are disappearing. In contrast, darker areas of open
water, which are expanding, absorb sunlight and increase temperatures.
This feedback loop has played a role in the increasingly rapid loss of
ice in recent years, which accelerated to 9.1 percent per decade from
1979 to 2006 according to satellite observations.

Walt Meier, Ted Scambos, and Mark Serreze, all at NSIDC, also co-
authored the study.