Fire Earth

Earth is fighting to stay alive. Mass dieoffs, triggered by anthropogenic assault and fallout of planetary defense systems offsetting the impact, could begin anytime!

Posts Tagged ‘WILKINS ICE SHELF’

Emerging Patterns of Vanishing Ice Shelves

Posted by feww on April 5, 2009

Catastrophic Sea-level Rises Are Almost a 100% Certainty

Wordie Ice Shelf has entirely vanished and the northern section of the Larsen Ice Shelf measuring about 10,000 sq km has disappeared in the last 20 years.


A view of the leading edge of the remaining part of the Larsen B ice shelf that extends into the northwest part of the Weddell Sea is seen in this handout photo taken on March 4, 2008. Mariano Caravaca (Handout via Reuters).

A report by the U.S. Geological Survey and others blames the climate change for what must surely be a prologue to a full-scale catastrophe in the Antarctica. The report and a detailed map of the region are available at  http://pubs.usgs.gov/imap/2600/B/ . The report says:

Antarctica is Earth’s largest reservoir of glacial ice. Melting of the West Antarctic part alone of the Antarctic ice sheet would cause a sea-level rise of approximately 6 meters …

“This continued and often significant glacier retreat is a wakeup call that change is happening … and we need to be prepared,” a USGS glaciologist, who led the Antarctica study, said.

“Antarctica is of special interest because it holds an estimated 91 percent of the Earth’s glacier volume, and change anywhere in the ice sheet poses significant hazards to society,” she said.

Meanwhile …

The Ice bridge that collapsed

A satellite picture reportedly acquired on Saturday showed that a 40 km strip of ice which held the Wilkins Ice Shelf in place was breaking up.

“It’s amazing how the ice has ruptured. Two days ago it was intact,” said David Vaughan, a glaciologist with the British Antarctic Survey, speaking about a satellite image of the Wilkins Ice Shelf on the Antarctic Peninsula, which was taken by the European Space Agency, ESA.

Antarctic Peninsula has experienced temperature rises of up to 3 °C in the past 50 years, the fastest warming rate in the region.

“We believe the warming on the Antarctic Peninsula is related to global climate change, though the links are not entirely clear,” Vaughan said.

Related Links:

Posted in Antarctic Peninsula, Climate Change, eco-terrorism, glacial ice, Ice bridge | Tagged: , , , , | 3 Comments »

If You Thought Antarctica, Too, Must Be Warming

Posted by feww on January 22, 2009

If you thought Antarctica, too, must be warming, not cooling [as some big oil mercenary ‘experts’ might have wanted you to believe,] you would be right, of course!

When massive ice shelves the size of Wilkins are rapidly calving, and there is no mechanism other than global warming to explain the events, you have to start asking questions about the validity of research that tells you the opposite!

Antarctica is warming [NOT cooling,] according to a new study led by Eric Steig of the University of Washington in Seattle. The findings of the study are consistent with the  overall global trend of warming.

antarctica-heating-up
Antarctica is warming like the rest of the globe! West Antarctica seems to be warming faster than the Antarctic Peninsula (the warmest regions shown in dark red), researchers said. Image Credit: NASA; Eric. J. Steig

The scientists review of satellite and weather records for Antarctica revealed that the icy  continent’s temperatures had risen by about  0.5 Celsius (0.8 Fahrenheit) in the last 50 years. Their study will be published in Thursday’s edition of the Nature.

“The thing you hear all the time is that Antarctica is cooling and that’s not the case,” said Eric Steig, confirming that the Antarctic average temperature rise was “very comparable to the global average.”

The study, based on a combination of temperature measurement by satellite over the past 25 years and data collected from more than 40 weather stations since the 1950s, contradicts previous “research” that most of the continent had cooled.

The “cooling” of Antarctica ruse has been used as a convenient tactic by big oil to argue that warming is a myth, and obfuscate other evidence of global warming.

News Links:

Related Links:

Posted in Antarctic ice shelf, Climate Change, Icebergs, Larsem B, melting ice | Tagged: , | 1 Comment »

WILKINS ICE SHELF IS “HANGING BY A THREAD”

Posted by feww on January 20, 2009

Antarctic ice shelf set to collapse due to warming

By Alister Doyle, Environment Correspondent

Tue Jan 20, 2009 8:42am EST

WILKINS ICE SHELF, Antarctica (Reuters) – A huge Antarctic ice shelf is on the brink of collapse with just a sliver of ice holding it in place, the latest victim of global warming that is altering maps of the frozen continent.


Between 1981 and 2007, most of Antarctica warmed. Portions of West Antarctica experienced an especially rapid rise in temperature. (NASA image by Robert Simmon, based on data from Joey Comiso, GSFC.)

“We’ve come to the Wilkins Ice Shelf to see its final death throes,” David Vaughan, a glaciologist at the British Antarctic Survey (BAS), told Reuters after the first — and probably last — plane landed near the narrowest part of the ice.

The flat-topped shelf has an area of thousands of square kilometers, jutting 20 meters (65 ft) out of the sea off the Antarctic Peninsula.

But it is held together only by an ever-thinning 40-km (25-mile) strip of ice that has eroded to an hour-glass shape just 500 meters wide at its narrowest.

In 1950, the strip was almost 100 km wide.

“It really could go at any minute,” Vaughan said on slushy snow in bright sunshine beside a red Twin Otter plane that landed on skis. He added that the ice bridge could linger weeks or months.

The Wilkins once covered 16,000 sq km (6,000 sq miles). It has lost a third of its area but is still about the size of Jamaica or the U.S. state of Connecticut. Once the strip breaks up, the sea is likely to sweep away much of the remaining ice.

Icebergs the shape and size of shopping malls already dot the sea around the shelf as it disintegrates. Seals bask in the southern hemisphere summer sunshine on icebergs by expanses of open water.


High-resolution satellite data show the Wilkins Ice Shelf collapse in detail, including blocks of ice that have tipped over and blocks of ice that have remained upright. (Formosat image © 2008 Dr. Cheng-Chien Liu, National Cheng-Kung University and Dr. An-Ming Wu, National Space Organization, Taiwan.)

A year ago, BAS said the Wilkins was “hanging by a thread” after an aerial survey. “Miraculously we’ve come back a summer later and it’s still here. If it was hanging by a thread last year, it’s hanging by a filament this year,” Vaughan said.

Nine other shelves have receded or collapsed around the Antarctic peninsula in the past 50 years, often abruptly like the Larsen A in 1995 or the Larsen B in 2002. The trend is widely blamed on climate change caused by heat-trapping gases from burning fossil fuels.

WARMING TO BLAME

“This ice shelf and the nine other shelves that we have seen with a similar trajectory are a consequence of warming,” Vaughan said.

In total, about 25,000 sq km of ice shelves have been lost, changing maps of Antarctica. Ocean sediments indicate that some shelves had been in place for at least 10,000 years.


Early in the day on February 28, 2008, the Wilkins Ice Shelf remained intact. By March 17, 2008, the ice shelf had retreated significantly from its original extent. As the Antarctic summer drew to a close, sea ice began to freeze around the ice fragments. (NASA images by Jesse Allen and Robert Simmon, based on MODIS data.)

Vaughan stuck a GPS monitoring station on a long metal pole into the Wilkins ice on behalf of Dutch scientists. It will track ice movements via satellite.

The shelf is named after Australian George Hubert Wilkins, an early Antarctic aviator who is set to join an exclusive club of people who have a part of the globe named after them that later vanishes.

Loss of ice shelves does not raise sea levels significantly because the ice is floating and already mostly submerged by the ocean. But the big worry is that their loss will allow ice sheets on land to move faster, adding extra water to the seas.


Large blocks of ice, recently broken off the Wilkins Ice Shelf, float on the ocean in this aerial photograph. In between the large blocks of ice float much smaller pieces of ice with a rough surface. (Photograph © 2008 British Antarctic Survey.)

Wilkins has almost no pent-up glaciers behind it. But ice shelves further south hold back vast volumes of ice. “When those are removed the glaciers will flow faster,” Vaughan said.

Temperatures on the Antarctic Peninsula have warmed by about 3 Celsius (5.4 Fahrenheit) since 1950, the fastest rise in the southern hemisphere. There is little sign of warming elsewhere in Antarctica.

BAS scientists and two Reuters reporters stayed about an hour on the shelf at a point about 2 km wide.

“It’s very unlikely that our presence here is enough to initiate any cracks,” Vaughan said. “But it is likely to happen fairly soon, weeks to months, and I don’t want to be here when it does.”

The U.N. Climate Panel, of which Vaughan is a senior member, projected in 2007 that world sea levels were likely to rise by between 18 and 59 cm (7 and 23 inches) this century.

But it did not factor in any possible acceleration of ice loss from Antarctica. Even a small change in the rate could affect sea levels, and Antarctica’s ice sheets contain enough water in total to raise world sea levels by 57 meters.

About 190 nations have agreed to work out a new U.N. treaty by the end of 2009 to slow global warming, reining in emissions from burning fossil fuels in power plants, cars and factories.

Following are facts about ice shelves.

  • Ice shelves are extensions of land-based ice sheets that float on the sea. They can be several hundred meters thick and are found mainly in bays around Antarctica, with some in the Arctic. Antarctica’s biggest, the Ross Ice Shelf, is the size of France.
  • Scientists worry that that the collapse of ice shelves could prompt glaciers inland to start sliding faster toward the sea, raising sea levels. Antarctica holds enough fresh water to raise sea levels by 57 meters (187 ft), so even a limited melt would have big consequences.
  • Since 1950, ten ice shelves on the Peninsula, which snakes up toward South America, have contracted or collapsed.
  • The British Antarctic Survey reckons that 25,000 sq km (10,000 sq mile) of ice shelves have been lost in total — an area the size of Macedonia, Rwanda or the U.S. state of Vermont.
  • Ice shelves that have broken up since 1950 are the Larsen A, Larsen B and Larsen C, Prince Gustav, Muller, Jones, Wordie, George VI north, George VI south and the Wilkins.
  • Among the most dramatic collapses was that of the Larsen A within a few weeks in 1995, when satellite images abruptly showed the bay dotted with icebergs. The Larsen B also abruptly collapsed in 2002.

(Editing by Andrew Roche) – copyright the author or the news agency.

Posted in Antarctica, Climate Change, Larsen A | Tagged: , , , , | 28 Comments »