On Aug 10, 2007, at 9:42 AM, Dwayne Monroe wrote:
> In a subscriber-only article over at New Scientist,
> NASA climate scientist James Hansen describes what the
> planet might look like after a "runaway collapse" of
> the West Antarctic ice sheet.
New York Times - August 10, 2007 <http://www.nytimes.com/2007/08/10/science/earth/10arctic.html>
Analysts See ‘Simply Incredible’ Shrinking of Floating Ice in the Arctic By ANDREW C. REVKIN
The area of floating ice in the Arctic has shrunk more this summer than in any other summer since satellite tracking began in 1979, and it has reached that record point a month before the annual ice pullback typically peaks, experts said yesterday.
The cause is probably a mix of natural fluctuations, like unusually sunny conditions in June and July, and long-term warming from heat- trapping greenhouse gases and sooty particles accumulating in the air, according to several scientists.
William L. Chapman, who monitors the region at the University of Illinois Urbana-Champaign and posted a Web report on the ice retreat yesterday, said that only an abrupt change in conditions could prevent far more melting before the 24-hour sun of the boreal summer set in September. "The melting rate during June and July this year was simply incredible," Mr. Chapman said. "And then you've got this exposed black ocean soaking up sunlight and you wonder what, if anything, could cause it to reverse course."
Mark Serreze, a sea-ice expert at the National Snow and Ice Data Center in Boulder, Colo., said his center's estimates differed somewhat from those of the Illinois team, and by the ice center's reckoning the retreat had not surpassed the satellite-era record set in 2005. But it was close even by the center's calculations, he said, adding that it is almost certain that by September, there will be more open water in the Arctic than has been seen for a long time. Ice experts at NASA and the University of Washington echoed his assessment.
Dr. Serreze said that a high-pressure system parked over the Arctic appeared to have caused a "triple whammy" — keeping away clouds, causing winds to carry warm air north and pushing sea ice away from Siberia, exposing huge areas of open water.
The progressive summertime opening of the Arctic has intensified a longstanding international tug of war over shipping routes and possible oil and gas deposits beneath the Arctic Ocean seabed.
Last week, Russians planted a flag on the seabed at the North Pole. On Wednesday, Stephen Harper, the Canadian prime minister, began a tour of Canada's Arctic holdings, pledging "to vigorously protect our Arctic sovereignty as international interest in the region increases."
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<http://arctic.atmos.uiuc.edu/cryosphere/>
Thursday, August 9, 2007 - New historic sea ice minimum
Today, the Northern Hemisphere sea ice area broke the record for the lowest recorded ice area in recorded history. The new record came a full month before the historic summer minimum typically occurs. There is still a month or more of melt likely this year. It is therefore almost certain that the previous 2005 record will be annihilated by the final 2007 annual minima closer to the end of this summer.
In previous record sea ice minima years, ice area anomalies were confined to certain sectors (N. Atlantic, Beaufort/Bering Sea, etc). The character of 2007's sea ice melt is unique in that it is dramatic and covers the entire Arctic sector. Atlantic, Pacific and even the central Arctic sectors are showing large negative sea ice area anomalies.
While we use sea ice concentration data supplied by NASA via the National Snow and Ice Data Center (NSIDC), there are some differences between the way we and NSIDC process our sea ice indices. NSIDC uses 10-day running means; we use 3-day running means. NSIDC will often report sea ice extent indices and records, we are reporting a new sea ice minima sea ice area. The ice area metric includes year-to-year variations within the central pack ice and not just variations in the southern sea ice edge. Regardless of these differences, the rapid rate of sea ice melt this summer, along with the current negative sea ice anomalies almost guarantees a record Northern Hemisphere summer sea ice minimum this summer, by any metric.