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http://www.usatoday.com/news/science/cold-science/2002-01-18-wais-thick…
Researchers find Antarctic ice is thickening
WASHINGTON (AP) — New measurements show the ice in West Antarctica is thickening, reversing some earlier estimates that the sheet was melting.
Jack Williams, USATODAY.com
Looking across the ice from an ice-core drilling tower at the Siple Dome field camp in 1999. Scientists drilled into the ice here to study the history of the West Antarctic Ice Sheet.
Scientists concerned about global warming have worried that higher temperatures could melt the massive ice sheet, causing a rise in sea levels worldwide.
But new flow measurements for the Ross ice streams, using special satellite-based radars, indicate that movement of some of the ice streams has slowed or halted, allowing the ice to thicken, according to a paper in the Jan. 18 issue of the journal Science.
If the thickening is not merely part of some short-term fluctuation, it represents a reversal of the long retreat of the ice, say researchers Ian Joughin of the California Institute of Technology and Slawek Tulaczyk of the University of California, Santa Cruz.
Their finding comes less than a week after a separate paper in Nature reported that Antarctica's harsh desert valleys — long considered a bellwether for global climate change — have grown noticeably cooler since the mid-1980s.
Air temperatures recorded continuously over a 14-year period ending in 1999 declined by about 1 degree Fahrenheit in the polar deserts and across the White Continent, that paper said.
The cooling defies a trend spanning more than 100 years in which average land surface temperatures have increased worldwide by about 1 degree Fahrenheit. The scientists said Antarctica is the only continent that is cooling. They can not say why.
In their paper, Joughin and Tulaczyk suggest the West Antarctic ice streams may be undergoing the same transition from shrinking to growing that appears to have occurred on a neighboring stream 150 years ago.
The results, they add, suggest a reduced possibility of the feared massive collapse of the ice field.
"Perhaps, after 10,000 years of retreat from the ice-age maximum, researchers turned on their instruments just in time to catch the stabilization or re-advance of the ice sheet," Richard B. Alley of Pennsylvania State University, wrote in a commentary accompanying the Science paper.
But he warned that coastal property owners should not become too optimistic about the findings, since the instrumental record is short and coastal ice streams have changed periodically over the centuries.
Yes, it's true the antarctic ice is getting thicker, but it's because of the massive hole in the ozone layer down in the southern hemisphere, not because global warming isn't real.
http://www.news.com.au/story/0,27574,25348657-401,00.html
Antarctic ice is growing, not melting away
By Greg Roberts
The Australian
April 18, 2009 11:52am
Text size
Cool down ... ice is expanding in much of the Antarctic, experts say / Reuters
Ice expanding in much of Antarctica
Eastern coast getting colder
Western section remains a concern
ICE is expanding in much of Antarctica, contrary to the widespread public belief that global warming is melting the continental ice cap.
The results of ice-core drilling and sea ice monitoring indicate there is no large-scale melting of ice over most of Antarctica, although experts are concerned at ice losses on the continent's western coast.
Antarctica has 90 per cent of the Earth's ice and 80 per cent of its fresh water, The Australian reports. Extensive melting of Antarctic ice sheets would be required to raise sea levels substantially, and ice is melting in parts of west Antarctica. The destabilisation of the Wilkins ice shelf generated international headlines this month.
However, the picture is very different in east Antarctica, which includes the territory claimed by Australia.
East Antarctica is four times the size of west Antarctica and parts of it are cooling. The Scientific Committee on Antarctic Research report prepared for last week's meeting of Antarctic Treaty nations in Washington noted the South Pole had shown "significant cooling in recent decades".
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It looks like a good news but again we have to wait a few years until all is re-checked, re-done and repeated by other surveys. The bottom line is the energy balance. If we capturin...
(Read More)
KBaus of Perth Australian Antarctic Division glaciology program head Ian Allison said sea ice losses in west Antarctica over the past 30 years had been more than offset by increases in the Ross Sea region, just one sector of east Antarctica.
"Sea ice conditions have remained stable in Antarctica generally," Dr Allison said.
The melting of sea ice - fast ice and pack ice - does not cause sea levels to rise because the ice is in the water. Sea levels may rise with losses from freshwater ice sheets on the polar caps. In Antarctica, these losses are in the form of icebergs calved from ice shelves formed by glacial movements on the mainland.
Last week, federal Environment Minister Peter Garrett said experts predicted sea level rises of up to 6m from Antarctic melting by 2100, but the worst case scenario foreshadowed by the SCAR report was a 1.25m rise.
Mr Garrett insisted global warming was causing ice losses throughout Antarctica. "I don't think there's any doubt it is contributing to what we've seen both on the Wilkins shelf and more generally in Antarctica," he said.
Dr Allison said there was not any evidence of significant change in the mass of ice shelves in east Antarctica nor any indication that its ice cap was melting. "The only significant calvings in Antarctica have been in the west," he said. And he cautioned that calvings of the magnitude seen recently in west Antarctica might not be unusual.
"Ice shelves in general have episodic carvings and there can be large icebergs breaking off - I'm talking 100km or 200km long - every 10 or 20 or 50 years."
Ice core drilling in the fast ice off Australia's Davis Station in East Antarctica by the Antarctic Climate and Ecosystems Co-Operative Research Centre shows that last year, the ice had a maximum thickness of 1.89m, its densest in 10 years. The average thickness of the ice at Davis since the 1950s is 1.67m.
A paper to be published soon by the British Antarctic Survey in the journal Geophysical Research Letters is expected to confirm that over the past 30 years, the area of sea ice around the continent has expanded.
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http://www.abc.net.au/science/articles/2009/04/22/2549626.htm
An expansion of sea ice around Antarctica is linked to a hole in the ozone layer high in the atmosphere, according to a study that helps clear up a mystery about global warming.
The finding, by scientists at the British Antarctic Survey (BAS) and the US space agency NASA, explains an apparent contradiction between the recent record thaw of ice in the Arctic and an increase in ice around Antarctica during the past 30 years.
"This new research helps us solve some of the puzzle of why sea ice is shrinking in some areas and growing in others," says John Turner of BAS and lead author of the report, which appears in the journal Geophysical Research Letters.
The scientists say damage to the ozone layer, which shields the planet from ultraviolet rays, cooled the stratosphere and disrupted wind patterns around Antarctica.
The shift meant winds blew off the continent more often, cooling the sea and creating more ice, they say.
"While there is increasing evidence that the loss of sea ice in the Arctic has occurred due to human activity, in the Antarctic human influence through the ozone hole has had the reverse effect and resulted in more ice," says Turner.
Sea ice around Antarctica has expanded at a rate of around 100,000 square kilometres per decade since the 1970s, and now covers an area of about 19 million square kilometres at its winter maximum, doubling the size of the continent.
By contrast, summer sea ice around the North Pole shrank in 2007 to the smallest since satellite records began in the 1970s.
Delayed effect
According to the study's authors, the ozone hole may also be delaying the effect of global warming on Antarctic sea ice.
"Although the ozone hole is in many ways holding back the effects of greenhouse gas increases on the Antarctic, this will not last, as we expect ozone levels to recover by the end of the 21st century," says Turner.
Dr Tony Worby of the Australian Antarctic Division, who was not involved in the study, says it's a really interesting hypothesis.
"The way sea ice is distributed around Antarctic has a lot to do with wind," he says.
"If you see long term changes in the way sea ice is distributed around Antarctica, one of the first things you would look at would be to understand whether there has been some shift in mean circulation in wind."
"We all know that different parts of the atmosphere are connected in different ways, so to see a surface signal from something happening in the stratosphere is an interesting result."
Worby says that while there has been an increase in the total area of Antarctic sea ice, the total volume of ice is relatively unknown.
"It's a bit hard to say because we don't know the thickness of the ice," he says. "We can measure the extent of the ice using satellites, but we don't have any satellite technology to tell us about thickness."
"The 1% increase [also] hides the fact that there is a huge decrease in sea ice around the Antarctic Peninsula," he says. "The devil is in the detail."
Boreal in the Sierra's opens tommorrow, earlier than ever before.
I'm supposed to leave for Kentucky tomorrow, for a riding trip with a bunch of people, but I think I'm gonna pass.. Too damn cold to camp for me!!
I'll just work on my house and hunt all weekend!
My ole lady bought me a new bow yesterday and I'm ready to kill me a deer with it!
Face it, everyone knows California/Nevada has the best skiing and snowboarding on the face of the planet.
Pit Row
Mammoth in California has the record worldwide for longest season open to close.
Tiki owned this thread.
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