Posted on 03/25/2008 11:02:27 AM PDT by NormsRevenge
A vast ice shelf hanging on by a thin strip looks to be the next chunk to break off from the Antarctic Peninsula, the latest sign of global warming's impact on Earth's southernmost continent.
Scientists are shocked by the rapid change of events.
Glaciologist Ted Scambos of the University of Colorado was monitoring satellite images of the Wilkins Ice Shelf and spotted a huge iceberg measuring 25 miles by 1.5 miles (41 kilometers by 2.5 kilometers - about 10 times the area of Manhattan) that appeared to have broken away from the shelf.
Scambos alerted colleagues at the British Antarctic Survey (BAS) that it looked like the entire ice shelf - about 6,180 square miles (16,000 square kilometers - about the size of Northern Ireland)- was at risk of collapsing.
David Vaughan of the BAS had predicted in 1993 that the northern part of the Wilkins Ice Shelf was likely to be lost within 30 years if warming on the Peninsula continued at the same rate.
"Wilkins is the largest ice shelf on the Antarctic Peninsula yet to be threatened," he said. "I didn't expect to see things happen this quickly. The ice shelf is hanging by a thread - we'll know in the next few days and weeks what its fate will be."
Aircraft reconnaissance
The BAS scientists sent an aircraft out on a reconnaissance mission to survey the extent of damage to the ice shelf.
Jim Elliot, who captured video of the breakout said, "I've never seen anything like this before - it was awesome. We flew along the main crack and observed the sheer scale of movement from the breakage. Big hefty chunks of ice, the size of small houses, look as though they've been thrown around like rubble - it's like an explosion."
An initial iceberg calved away from the Wilkins Ice Shelf on Feb. 28. A series of images shows the edge of the ice shelf proceeding to crumble and disintegrate in a pattern characteristic of climate-caused ice shelf retreats throughout the northern Antarctic Peninsula. The disintegration left a sky-blue patch of hundreds of large blocks of exposed old glacier ice floating across the ocean surface.
By March 8, the ice shelf had lost just over 220 square miles (570 square kilometers) of ice, and the disintegrated ice had spread over 540 square miles (1,400 square kilometers). As of mid-March only a narrow strip of shelf ice between Charcot and Latady islands was protecting several thousand more kilometers of the ice shelf from potentially breaking up.
The region where the Wilkins Ice Shelf lies has experienced unprecedented warming in the past 50 years, with several ice shelves retreating in the past 30 years. Six of these ice shelves have collapsed completely: Prince Gustav Channel, Larsen Inlet, Larsen A, Larsen B, Wordie, Muller and the Jones Ice Shelf.
Antarctic warming
The Wilkins Ice Shelf was stable for most of the last century until it began retreating in the 1990s. A previous major breakout occurred there in 1998 when 390 square miles (1,000 square kilometers) of ice was lost in just a few months.
"We believe the Wilkins has been in place for at least a few hundred years, but warm air and exposure to ocean waves are causing it to break up," Scambos said.
The Antarctic Peninsula has warmed faster than anywhere else in the Southern Hemisphere; temperature records show that the region has warmed by nearly 3 degrees Celsius during the past 50 years - several times the global average and only matched in Alaska.
Other parts of Antarctica, including the East Antarctic Ice Sheet, seem to be more stable, though areas of melt have been observed in recent years.
Melting in the Antarctic is different than the recent record melt in the Arctic. Antarctica is composed of ice sheets, or huge masses of ice up to 2.5 miles (4 kilometers) thick that lie on top of bedrock and flow toward the coast, and ice shelves, the floating extensions of ice sheets. Arctic ice is primarily sea ice, some of which persists year-round and some of which melts in the summer and freezes again in the winter.
Norm - why post twice?
The region where the Wilkins Ice Shelf lies has experienced unprecedented warming in the past 50 years, with several ice shelves retreating in the past 30 years. Six of these ice shelves have collapsed completely: Prince Gustav Channel, Larsen Inlet, Larsen A, Larsen B, Wordie, Muller and the Jones Ice Shelf.
Let's just wait and see whether the sea levels rise and swamp the world's coastal cities. Otherwise, these reports are pure bunk.
Meanwhile, other parts of Antarctica’s ice sheets are thickening.
When the water up there gets to bathtub temperature then let me know....I’ll call my travel agent.
Im whacking the first one, beats me what happened, mouce button bounce?
Oh, No! Not Again!
Ooh! I wanna see! I wanna see!
Relax. It's just Ted Kennedy stocking up on ice for his next party.
A map of the Antarctic Peninsula with the location of the the Wilkins Ice Sheet,
which is on the southern portion of the peninsula.
Credit: British Antarctic Survey
“Im whacking the first one, beats me what happened, mouce button bounce?”
I’ve noticed sometimes posts go through twice...especially when the server seems to hang.
Save the Polar Bears!.............oh, wait, they ain’t no polar bears there!........Then it’s okay.....
It’s not you mouse, it’s you .....
If I let the ice melt completely in my Jack & Coke, the level goes down .( without drinking)
I am still upset about the lose of that melting glacier which covered most of the midwest 15,000 years ago.
IBBF.
If they tow this sucker to the north pole the Polar bears will have somewhere to rest.......
"And Leon's getting laaaarger!!"
Well then it must be global warming if it's retreating in a manner "characteristic of climate-caused ice shelf retreats". Otherwise, it'd be retreating in a manner of normal ice shelf retreats. /s
I know I will be on pins and needles. /s
We’re all going to die?
Those shelves have probably never been a constant size for more than a century or two for the entire history of the earth.
Who knows what the size of them were 300 years ago, a mere eye blink in the life of this planet? We have no real idea of how fast they ebb and wain over extended periods of time, yet it is written and taken as gospel that we are the cause of this and not the sun.
“Glaciologist Ted Scambos of the University of Colorado was monitoring satellite images of the Wilkins Ice Shelf and spotted a huge iceberg measuring 25 miles by 1.5 miles (41 kilometers by 2.5 kilometers - about 10 times the area of Manhattan) that appeared to have broken away from the shelf.”
Quick! Tow it it a place that needs fresh water!
Quick! Tow it it a place that needs fresh water!.......like Colorado......
“I am still upset about the lose of that melting glacier which covered most of the midwest 15,000 years ago.”
Me too! I think we should petition congress for compensation. Or, at least, an apology!
Saber Tooth’s lied - Wooly Mammoths died.
Personally, I blame the Indians. They were the only ones around, and all those smoke signals had to contribute to higher levels of CO2 in the atmosphere.
Wasn’t that photo debunked in an article posted yesterday?
From the article:
“We believe the Wilkins has been in place for at least a few hundred years, but warm air and exposure to ocean waves are causing it to break up,” Scambos said.
So, did we have more global warming a few hundred years ago, AFTER which the Wilkins formed?
“Quick! Tow it it a place that needs fresh water!.......like Colorado......”
Eck-chually, I had a coastal area in mind.
Now that you mention it, though, I wonder what the economics would be of mooring the ice, building a small pipeline (with few of the safety features needed for a petroleum pipeline), then putting a pumping station on the ice.
Wasn’t that photo debunked in an article posted yesterday?
—
don’t know, first I had seen anything about this today.. link it up, Thx!
ScienceDaily (May 31, 2004) — ARLINGTON, Va. -- Scientists working in the stormy and inhospitable waters off the Antarctic Peninsula have found what they believe is an active and previously unknown volcano on the sea bottom.
Highly sensitive temperature probes moving continuously across the bottom of the volcano revealed signs of geothermal heating of seawater.
http://www.sciencedaily.com/releases/2004/05/040527235943.htm
Looks like they could attach motors to it and drive it somewhere.............
It was either bunked or debunked. Sometimes it is hard to tell the difference.
Maybe rebunked?
http://www.middlebury.net/op-ed/global-warming-01.html
“At left is a screen shot from the Greenpeace web site, from a video which drips with the urgency of stopping the “melting” of the Arctic Ice Pack.
But look closely: Those are shear lines, where the ice has broken, not “melted”. Melting does not occur in particular paths across the ice sheet, except when being zapped by aliens in UFO’s.”
from that neck of the woods, not so long ago..
Images of Wilkins Ice Shelf Breakup
Source: Breakup of the Larsen B Ice Shelf: 15 February 1998 - 18 March 1999
http://nsidc.org/iceshelves/larsenb1999/wilkins.html
and an big file for a sat pic, 2.1MB
http://nsidc.org/cgi-bin/new/iceshelves_images.pl
Huh? This is sea ice. When sea ice melts it obviously has no effect on sea levels. It's already in the ocean. However, sea ice may bottle up glaciers, keeping them on land -- with this shelf out of the way, those glaciers may flow into the ocean, something that would, obviously, raise sea levels.
I don't think there are enough tugboats on the planet to tow an iceberg the size of Northern Ireland.
“By March 8, the ice shelf had lost just over 220 square miles (570 square kilometers) of ice, and the disintegrated ice had spread over 540 square miles (1,400 square kilometers).
The region where the Wilkins Ice Shelf lies has experienced unprecedented warming in the past 50 years, with several ice shelves retreating in the past 30 years. Six of these ice shelves have collapsed completely: Prince Gustav Channel, Larsen Inlet, Larsen A, Larsen B, Wordie, Muller and the Jones Ice Shelf.”
And yet we continue to live. The cities haven’t flooded, the crops haven’t failed. So what’s the big deal?
Gravity
And no one’s gettin’ fat except Mama Cass!
How does sea ice “bottle up” glaciers?
Sea ice is highly unstable and much softer than fresh water ice. In addition to that, there would be nothing to stop a glacier flow from pushing sea borne ice out of it’s way.
What stops most glacier movement is terrain. Mountain ranges are mostly responsible for holding Antarctica’s ice on the continent. There are a few ice flows where there are breaks in the mountainous terrain, so the ice flows to the ocean at those points.
HE COULD! ALL BY HISSELF!..........
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