BERLIN, April 29, 2009
Massive Ice Chunks Break Up In Antarctica
Huge Chunks Crumbling Away From Shelf Due To Warming; Scientists Warn Of More Instability
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An Envisat Advanced Synthetic Aperture Radar (ASAR) image dated April 28, 2009 and made available on Wednesday, April 29, 2009 shows the breaking away of the ice bridge of the Wilkins Ice Shelf in Antarctica. (AP Photo/European Space Agency)
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Interactive Global Warming The greenhouse effect, a look at the Kyoto Protocol and a history of the Earth's climate.
The Wilkins Ice Shelf had been stable for most of the last century, but began retreating in the 1990s. Researchers believe it was held in place by an ice bridge linking Charcot Island to the Antarctic mainland.
But the 127-square-mile bridge lost two large chunks last year and then shattered completely on April 5.
"As a consequence of the collapse, the rifts, which had already featured along the northern ice front, widened and new cracks formed as the ice adjusted," the European Space Agency said in a statement Wednesday on its Web site, citing new satellite images.
The first icebergs broke away on Friday, and since then some 270 square miles of ice have dropped into the sea, according to the satellite data.
"There is little doubt that these changes are the result of atmospheric warming," said David Vaughan of the British Antarctic Survey.
The falling away of Antarctic ice shelves does not, in itself, raise sea levels, since the ice was already floating in the sea. But such coastal tables of ice usually hold back glaciers, and when they disintegrate that land ice will often flow more quickly into the sea, contributing to sea-level rise.
Researchers said the quality and frequency of the ESA satellite images have allowed them to analyze the Wilkins shelf breakup far more effectively than any previous event.
"For the first time, I think, we can really begin to see the processes that have brought about the demise of the ice shelf," Vaughan said.
He said eight ice shelves along the Antarctic Peninsula have shown signs of retreat over the last few decades.
"The retreat of Wilkins Ice Shelf is the latest and the largest of its kind," he said.
The Wilkins shelf, which is the size of Jamaica, lost 14 percent of its mass last year, according to scientists who are looking at whether global warming is the cause of its breakup.
Average temperatures in the Antarctic Peninsula have risen by 3.8 degrees Fahrenheit over the past 50 years - higher than the average global rise, according to studies.
Over the next several weeks, scientists estimate the Wilkins shelf will lose some 1,300 square miles - a piece larger than the state of Rhode Island, or two-thirds the size of Luxembourg.
One researcher said, however, that it was unclear how the situation would evolve.
"We are not sure if a new stable ice front will now form between Latady Island, Petrie Ice Rises and Dorsey Island," said Angelika Humbert of Germany's Muenster University Institute of Geophysics.
But even more ice could break off "if the connection to Latady Island is lost," she said, "though we have no indication that this will happen in the near future."
© MMIX, The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.
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See all 47 CommentsI don't know.
I thought that maybe if the ice sheets were growing, they wouldn't be breaking up and getting smaller.
And if the sea ice in the Antarctic were growing for the last several years, I wouldn't expect it to have been shrinking substantially for the last several years.
Call me crazy . . .
Is this not what we would expect if the ice sheets were growing? The extent of sea ice in the Antarctic certainly has been growing for several years. Nevertheless, we have another "news" item based mostly on "predictions," the most slant-susceptible form of alleged information.
BTW, how, on April 28, 2009, did they make a (radar) photograph of an event in progress, if the event was completed on April 5?
http://wattsupwiththat.com/2009/04/30/watch-the-wilkins-ice-shelf-collapse-looks-like-current-events-to-me/
the conclusion being:
"the continent-wide average near-surface temperature trend is positive.""
You're referring to the Steig, Mann made global warming antarctic paper? I suggest you read Jeff Id's very fine replication of the study (at least as good as he could do without the original data, since the Hockey Team won't publish it), and his many (more correct) approaches before you decide how robust the continent wide temperature trend is. Steig's paper's results depend entirely on the weighting of the PC's, which have no real attachment to physical locations on the ground. Choose a different number of PC's while using RegEM and see what happens. More cherry picking by the Team. Choose the lowest starting point, it is possible, with enough manipulation, to achieve a statistically insignificant positive trend. Choose any other point, NADA. Yes, the WAIS has warmed somewhat, most likely due to normal ocean circulation & oscillations. The rest of the continent? No. Sea Ice has increased enough around Antarctica in the last few decades to fit an additional 5 Michigans. Get it? Now how could that be if the continent is experiencing a net warming? Do I have to un-learn physics now too?
Read Jeff's analysis here, http://noconsensus.wordpress.com and more interesting tidbits here http:climateaudit.org
Prove me wrong.
Dr. Idso went on to claim that REGARDLESS of what we do to our atmosphere, the property of emmissivity (ability to absorb outgoing radiation) and thermal equlibrium would prevent an overall warming of more than about 4 to 5 degrees celsius (7 to 9 degrees F). The most our globe would warm up is about 4 or so degrees from present temperatures.
O.K.....Most of us who have a passing knowledge of Global Warming's history of controversy also know that Dr. Idso sold his soul to the petrochemical industry in the late 80's and anything he says now with regard to climate change must be suspect as politically tainted. But in the late 70's and up to about 1988, he did pretty good science.
So, let's assume he was right about the maximum heat capacity of our atmosphere - even given a doubling or even quadrupling of the amount of CO2 in it and play what if.....
For example we can set the warming to "only" 2 degrees F, or half of Idso's theoretical maximum, bringing the global average temperature to roughly 60.5 degrees. I might mention in passing we've never seen it that high during this interglacial; not even during the Medieval Warm Period. If we review how much the planet has warmed overall (without speculating as to why) since 1970 and we arrive at about 0.8 degrees. Doesn't sound like much, does it? It isn't - unless you live near the poles. I plotted the temperature increase in my hometown since 1970 and came up with about 0.7; did the same for Barrow, Alaska and got nearly 3.5! I used data from the Western Regional Climate Center based In Reno, NV. We're talking a four-fold increase in warming rate. Some towns in the Canadian Arctic saw average temperatures go up by as much as 5 degrees. The same degree of warming weirdness is also going on in northern Europe and Asia. Assuming a simple linear function for our temperature response, we can expect polar regions to warm up as much as 6 times over the global average. If this function is exponential, however, then all bets are off with respect to high latitude heating; 2 degrees of additional world-wide warming doesn't seem so trivial, now.
What this means is IF the planet is warming up as some say and IF we warm up "only" two degrees and IF the warming response is amplified at higher latitudes as much as it appears to be....THEN we're in for a prodigious amount of melting in the arctic. And as for the Antarctic? Any cooling observed there now will abruptly reverse and we could see several degrees of warming even there.
All speculative, to be sure. But this speculation is based on warming already observed and even if things have cooled off a bit since 2000, the high latitude amplification signal already noted is very much evident. In both hemispheres.
We stand not only to lose all of our ice shelves but a goodly chunk of both East and West sheets will end up in the Indian and Pacific Oceans as well. Draw your own conclusions on what that means but those now living on or near seacoasts can expect to have an increasingly difficult time keeping the surf out of their living rooms.
It's real.
It's happening now.
It's man-made.
The consequences are catastrophic.
The time for action is now if we want to save the planet we live on.
Posted by BeckieBest at 8:21 AM : Apr 30, 2009
Let's be clear, Global Warming will not destroy the planet, just ALL LIFE AS WE KNOW IT!
Planet Earth may look just like Mars (not red of course) a lifeless rock in orbit.
Posted by NOinhale at 8:36 AM : Apr 30, 2009
No thanks. I will swim to Europe.
It's real.
It's happening now.
It's man-made.
The consequences are catastrophic.
The time for action is now if we want to save the planet we live on.
http://www.coolantarctica.com/Antarctica%20fact%20file/science/global_warming.htm
Nature magazine cover story:
http://www.nature.com/nature/journal/v457/n7228/abs/nature07669.html
the conclusion being:
"the continent-wide average near-surface temperature trend is positive."
Also discussed in
http://www.realclimate.org/index.php/archives/2009/02/antarctic-warming-is-robust/langswitch_lang/it
I would think its getting difficult to find any scientist, at all, who isn't on the AGW bandwagon. Its real, its happening, and any scientist who denies it is risking being thought a fool by his/her peers, at this point.
Which leaves us with poor nazdackster for independent 'critical' thought. Still trying to argue that the world is flat.
It's real.
It's happening now.
It's man-made.
The consequences are catastrophic.
The time for action is now if we want to save the planet we live on.
Posted by BeckieBest at 6:31 AM : Apr 30, 2009
Not that the theory is wrong, but your "The Scientific debate over global warming is over." is not how true scientist operate. Any real scientist (those without an agenda) will tell you there are no absolutes in scientific research.
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