Posted on 12/28/2006 6:09:36 AM PST by Clive
An ancient ice shelf has cracked off northern Ellesmere Island, creating an enormous, 66-square-kilometre ice island and leaving a trail of icy blocks in its wake.
''It really is incredible,'' says Warwick Vincent of Laval University, one of the few people to have laid eyes on the scene. ''It's like a cruise missile has come down and hit the ice shelf.''
The breakup was so powerful, earthquake monitors 250 kilometres away picked up the tremors as the 3,000 to 4,500 year-old shelf tore away from its fjord on Ellesmere.
It broke up 16 months ago, but no one was present to see it. The scientists say they are only now releasing details after piecing together what occurred using seismic monitors and Canadian and U.S. satellites.
They say the ice shelf collapse is the biggest in Canada in 30 years and is indicative of the transformation underway on Ellesmere, Canada's most northern landmass.
''We're seeing incredible changes,'' says Vincent, whose group is studying the island's disappearing ice shelves and their unique ecosystems.
''People talk of endangered animals - well, these are endangered landscape features, and we're losing them,'' says Vincent. In 2002, his graduate student Derek Mueller discovered Ellesmere's Ward Hunt Ice Shelf had cracked in half. The researchers have also seen the sudden collapse of ice dams and the draining of 30-kilometre-long lakes into the sea.
The Ayles Ice Shelf was one of six ice shelves left in Canada, remnants of a vast icy fringe that used to cover the top end of Ellesmere. Scientists consider the Canadian shelves, located about 800 kilometres south of the North Pole, sentinels that reflect the accelerating change in the Arctic.
The shelves are 90 per cent smaller than they were when Arctic explorer Robert Peary crossed them in 1906. And the Ayles ice shelf can now be erased from Canada's maps. ''It no longer exists,'' says Vincent.
Laurie Weir, of the federal Canadian Ice Service in Ottawa, was poring over images from the RADARSAT satellite when she noticed the shelf had broken away. She passed the information on to Luke Copland, head of the new global ice lab at the University of Ottawa, who led the effort to determine what had happened.
It turned out it took less than an hour for the ice shelf to calve off in the early afternoon of Aug. 13, 2005, says Copland. Low frequency ''rumbling'' and tremors were picked up on Alert's earthquake monitors, and Canadian and U.S. satellites captured images of the shelf cracking and breaking away.
''If you were standing right on the edge of the shelf, there'd have been this huge 15-kilometre crack as far as you could see in both directions,'' says Copland. ''And then the ice drifted off.'' Within an hour, the giant ice island was a kilometre offshore. It travelled west about 50 kilometres over the next few weeks, and then moved east before freezing into the sea ice about 15 kilometres offshore.
Copland has reconstructed what happened with Weir and Mueller, who is now at the University of Alaska in Fairbanks. ''We have a really good sequence of the ice shelf breaking up and then floating away,'' says Copland.
Vincent flew out from his base camp on Northern Ellesmere by helicopter earlier this year to have a first-hand look at the scene of the collapse. ''There was a huge amount of rubble associated with this breakup,'' says Vincent, explaining how the fjord is now full of ice blocks. ''And then this vast ice shelf floating offshore.''
The ice island is about 37 metres thick and measures roughly 15 kilometres by five kilometres. That's the size of a small city, or larger than 11,000 football fields. The island is now stuck in the winter ice, but the researchers believe it is just a matter of time before it is freed and floats away. They say the ice island could become a potential hazard to navigation and oil and gas extraction if it sails south towards the Beaufort Sea.
But for now, it is a monument to change.
''This is the biggest event since the '80s in terms of ice shelf loss, '' says Copland. He says two key factors appear to have triggered the break up - the exceptionally warm temperatures on Ellesmere in the summer of 2005, which was three degrees Celsius above normal, and unusually brisk winds that blew the summer pack ice offshore, exposing the Ayles shelf to waves and open water. Normally, the prevailing winds blow summer pack ice up against Ellesmere's ice shelves, where it acts likes a buffer, protecting them from the sea.
The scientists say they can't prove human-induced climate change caused the Ayles shelf to break off, but they suspect global warming may be responsible.
''We can say it is consistent with the larger body of evidence indicating the climate is warming and predictions that the greatest effects are likely to take place at high latitudes,'' says Vincent. He notes that the Ayles disintegration is just the most recent of several abrupt changes on Ellesmere.
''Suddenly lakes that existed aren't there any more. Ice dams collapse. Ice shelves break up,'' says Vincent. ''These are big changes.''
Researchers say there are many more changes in store. Last week a Canada-U.S. team predicted that the Arctic Ocean could be devoid of summer ice as early as 2040, and possibly sooner.
-
Pray tell, what was there before the ice shelf? Take your time...
Push it up to the Potomac to melt. Flood DC and solve the nation's problems...
Amen!
They are called "icebergs".
Just in case anybody forgot where icebergs come from.
So global warming is a "disaster"? Not unless ships go ramming into the icebergs.
Never hear a peep about the sun from these people...
Why should they bother trying to prove it? Sheeple will just believe it anyway.
Gee, maybe we should go back to the good ol' days when half of North America and Europe were covered by ice sheets. What on EARTH posesses these idiots to think first that ice is some kind of steady-state landscape, and second, that bitter cold is a good thing for humanity?
"Pray tell, what was there before the ice shelf? Take your time..."
got to be my other black sock
"The shelves are 90 per cent smaller than they were when Arctic explorer Robert Peary crossed them in 1906. And the Ayles ice shelf can now be erased from Canada's maps. ''It no longer exists,'' says Vincent. "
1906? Roosevelt's Fault!!!
Hmm. Was the globe warming in the '80s, too?
Source: Chicken Little as reported by Al Gore in "Earth in the Balance."
And there you have it. Scientists demand absolute proof most times (especially with regard to religion) but global warming requires a different standard - only SUSPICION is required.
Of course, all scientists are idiots and their views are purely political, without merit, and ignorant.
I love it when a world-changing, cataclysmic event goes unnoticed for a year and a half.
Two entirely dirrerent things ...
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.