Arctic Sea Ice extent is still shrinking according to NASA and the National Snow and Ice Data Center. The thickness of Arctic ice is also reducing. Over the 2009 winter the Arctic had the fifth lowest maximum ice extent on record. The six lowest maximum events since satellite monitoring began in 1979 have all occurred in the past six years (2004-2009).
The composition of the sea ice continues to change. Thin seasonal ice that melts and re-freezes every year now makes up about 70 percent of the Arctic sea ice in wintertime, up from 40 to 50 percent in the 1980s and 1990s. Thicker ice, which survives two or more years, now comprises just 10 percent of wintertime ice cover, down from 30 to 40 percent. The maximum sea ice extent for 2008-09, reached on Feb. 28, was 5.85 million square miles. That is a reduction of 278,000 square miles from the average extent for 1979 to 2000.
http://nsidc.org/arcticseaicenews/
According to scientists Arctic sea ice works like an air conditioner for the global climate system. The Sea Ice cools air and water masses, playing a key role in ocean circulation, and also reflects solar radiation back into space. Arctic Sea ice also helps refrigerate the Greenland Ice Cap to keep it cold and stable, although research is showing substantial warming changes to the coast of Greenland.
Information on the trends for Sea Ice Cover was provided in a media conference on April 6 by Ronald Kwok, research scientist, NASA's Jet Propulsion Laboratory; Walter Meier, cryosphere scientist, National Snow and Ice Data Center, University of Colorado; and Thomas Wagner, cryosphere program manager, NASA Headquarters, Washington.
Reasearch in 2008 revealed substantial warming on Greenland's north coast with the ice sheet experiencing extreme melting. The average temperature between June and August 2008 was as much as 3 degrees Celsius above average at ground based weather stations. Ice sheet models from 2006 project that warming would initiate the long-term melting of the ice sheet, leading to a complete melting of the Greenland ice sheet over several millennia, resulting in a global sea level rise of about seven meters.
According to a team of researchers led by University of Wisconsin-Madison geologist Anders Carlson sea level rise from greenhouse-induced warming of the Greenland ice sheet could be double or triple current estimates over the next century. "We're not talking about something catastrophic, but we could see a much bigger response in terms of sea level from the Greenland ice sheet over the next 100 years than what is currently predicted," said Carlson in a report in Science Daily in September 2008.
http://www.climateimc.org/en/image/global/polar-regions/greenland-ice-ca...
See Also
* Climate IMC - Jan 4, 2006 - Greenland Ice Sheet melting faster than expected
http://www.climateimc.org/en/breaking-news/2006/01/04/greenland-ice-shee...
* Climate IMC - Feb 20, 2006 - NASA's Jim Hansen on Greenland ice pack
http://www.climateimc.org/en/breaking-news/2006/02/19/nasas-jim-hansen-g...
* Climate IMC - Oct 12, 2007 - Arctic Sea Ice heading for Rapid Disintegration: Greenland Ice Sheet melting
http://www.climateimc.org/en/original-news/2007/10/11/arctic-sea-ice-hea...
* Wikipedia - Greenland Ice Sheet
http://en.wikipedia.org/wiki/Greenland_ice_sheet
Sources:
* NASA April 6, 2009 - Satellites Show Arctic Literally on Thin Ice
http://www.nasa.gov/topics/earth/features/arctic_thinice.html
* NASA Feb 25, 2009 - Melting on the Greenland Ice Cap, 2008
http://earthobservatory.nasa.gov/IOTD/view.php?id=37215
* Science Daily Sep 1, 2008 - Faster Rise In Sea Level Predicted From Melting Greenland Ice Sheet, Based On Lessons From Ice Age
http://www.sciencedaily.com/releases/2008/08/080831151346.htm
Comments
Copenhagen travel
Anyone going from SW France next week Dec 8/9, I need a ride share.
Sea Ice Levels
Sea Ice Ends Year at Same Level as 1979 (posted In Daily
Tech January 1, 2009)
“Rapid growth spurt leaves amount
of ice at levels seen 29 years ago.
“Thanks to a rapid rebound in recent months, global sea ice
levels now equal those seen 29 years ago, when the year 1979
also drew to a close.
“Ice levels had been tracking lower throughout much of 2008, but rapidly
recovered in the last quarter. In fact, the rate of increase from September
onward is the fastest rate of change on record, either upwards or downwards.
“The data is being reported by the University
of Illinois's Arctic Climate
Research Center,
and is derived from satellite observations of the Northern and Southern
hemisphere polar regions.
“Each year, millions of square kilometers of sea ice melt and refreeze.
However, the mean ice anomaly -- defined as the seasonally-adjusted difference
between the current value and the average from 1979-2000, varies much more
slowly. That anomaly now stands at just under zero, a value identical to one
recorded at the end of 1979, the year satellite record-keeping began.”
Arctic Sea Ice Recovers Slightly but still trending Downward
Amos, the extent of arctic ice may have grown substantially for one season, but much of it is 1st year and 2nd year ice prone to re-melting in the arctic summer.
Arctic Sea Ice Recovers Slightly in 2009, Remains on Downward Trend
October 6, 2009
Despite a slight recovery in summer Arctic sea ice in 2009 from
record-setting low years in 2007 and 2008, the sea ice extent remains
significantly below previous years and remains on a trend leading
toward ice-free Arctic summers, according to the University of Colorado
at Boulder's National Snow and Ice Data Center.
According to the CU-Boulder center, the 2009 minimum sea ice extent
was the third lowest since satellite record-keeping began in 1979. The
past five years have seen the five lowest Arctic sea ice extents ever
recorded.
"It's nice to see a little recovery over the past couple of years,
but there's no reason to think that we're headed back to conditions
seen in the 1970s," said NSIDC Director Mark Serreze, also a professor
in CU-Boulder's geography department. "We still expect to see ice-free
summers sometime in the next few decades."
....more at
http://earthobservatory.nasa.gov/Newsroom/view.php?id=40666
Just in case people still
Just in case people still don't get it ;)
from here: http://nsidc.org/data/seaice_index/
bluster
You'd extrapolate a trend from that? Two data points? Even if it were true... http://tamino.wordpress.com/2009/01/08/cold-hard-facts/
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