Massive ice shelf on verge of breakup

Discussion in 'Environment' started by JimH52, Mar 25, 2008.

  1. JimH52
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    JimH52 Gold Member

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    http://www.cnn.com/2008/TECH/science/03/25/antarctic.ice/index.html

    Massive ice shelf on verge of breakup

    (CNN) -- Some 220 square miles of ice has collapsed in Antarctica and an ice shelf about the size of Connecticut is "hanging by a thread," the British Antarctic Survey said Tuesday, blaming global warming.
    "We are in for a lot more events like this," said professor Ted Scambos, a glaciologist at the National Snow and Ice Data Center at the University of Colorado at Boulder.
    Scambos alerted the British Antarctic Survey after he noticed part of the Wilkins ice shelf disintegrating on February 28, when he was looking at NASA satellite images.
    Late February marks the end of summer at the South Pole and is the time when such events are most likely, he said. Watch aerial footage of the area »
    "The amazing thing was, we saw it within hours of it beginning, in between the morning and the afternoon pictures of that day," Scambos said of the large chunk that broke away on February 28.
    The Wilkins ice shelf lost about 6 percent of its surface a decade ago, the British Antarctic Survey said in a statement on its Web site
    Another 220 square miles -- including the chunk that Scambos spotted -- had splintered from the ice shelf as of March 8, the group said.

    "As of mid-March, only a narrow strip of shelf ice was protecting several thousand kilometers of potential further breakup," the group said.
    Scambos' center put the size of the threatened shelf at about 5,282 square miles, comparable to the state of Connecticut, or about half the area of Scotland.
    Once Scambos called the British Antarctic Survey, the group sent an aircraft on a reconnaissance mission to examine the extent of the breakout.
    "We flew along the main crack and observed the sheer scale of movement from the breakage," said Jim Elliott, according to the group's Web site.
    "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," he said.
    "Wilkins is the largest ice shelf on the Antarctic Peninsula yet to be threatened," David Vaughan of the British Antarctic Survey said, according to the Web site.
    "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 or weeks what its fate will be."
    But with Antarctica's summer ending, Scambos said the "unusual show is over for this season."
    Ice shelves are floating ice sheets attached to the coast. Because they are already floating, their collapse does not have any effect on sea levels, according to the Cambridge-based British Antarctic Survey.
    Scambos said the ice shelf is not currently on the path of the increasingly popular tourist ships that travel from South America to Antarctica. But some plants and animals may have to adapt to the collapse.
    "Wildlife will be impacted, but they are pretty adept at dealing with a topsy-turvy world," he said. "The ecosystem is pretty resilient."
    Several ice shelves -- Prince Gustav Channel, Larsen Inlet, Larsen A, Larsen B, Wordie, Muller and Jones -- have collapsed in the past three decades, the British Antarctic Survey said.
    Larsen B, a 1,254-square-mile ice shelf, comparable in size to the U.S. state of Rhode Island, collapsed in 2002, the group said.
    Scientists say the western Antarctic peninsula -- the piece of the continent that stretches toward South America -- has warmed more than any other place on Earth over the past 50 years, rising by 0.9 degrees Fahrenheit each decade.
    Scambos said the poles will be the leading edge of what's happening in the rest of the world as global warming continues.
    "Even though they seem far away, changes in the polar regions could have an impact on both hemispheres, with sea level rise and changes in climate patterns," he said.
    News of the Wilkins ice shelf's impending breakup came less than two weeks after the United Nations Environment Program reported that the world's glaciers are melting away and that they show "record" losses.

    Data from close to 30 reference glaciers in nine mountain ranges indicate that between the years 2004-2005 and 2005-2006 the average rate of melting and thinning more than doubled," the UNEP said March 16.
    The most severe glacial shrinking occurred in Europe, with Norway's Breidalblikkbrea glacier, UNEP said. That glacier thinned by about 10 feet in 2006, compared with less than a foot the year before, it said
     
  2. Bern80
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    Bern80 Gold Member

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  3. maineman
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    maineman BANNED

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    there are variations in weather, and then there are changes in climate.

    apples and oranges.
     
  4. Bern80
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    Bern80 Gold Member

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    Well aware. The fact that it is warmer one place and colder in another would both be considered climate changes, would they not?
     
  5. maineman
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    maineman BANNED

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    a colder than normal winter in China is a variation in seasonal weather. An incremental increase in air temp and water temp and a reduction in the ozone layer causing more direct sunlight to reach the antarctic ice shelf is indicative of climate change. apples and oranges
     
  6. Bern80
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    Bern80 Gold Member

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    Possibly. However if China were to have consistant colder than 'normal' winters it would be considered apples to apples. Just as if we were observing the ice shelves 10 years ago you would have to consider the begining of the warming a weather related event. The point is maybe it is apples to oranges and maybe it isn't.
     
  7. maineman
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    perhaps. And clearly, global warming can cause shifts in weather patterns that cause some areas to experience colder average temperatures due to shifts in ocean currents caused by melting pack ice.
     
  8. TopGunna
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    Meh....

    Only 2% of the Antarctic land mass is experiencing warming. The rest of the continent is seeing more snowfall and ice formation and the same or colder temperatures.

    Furthermore, the average Antarctic temperature is -50°C (-58°F). So a slight warming might stimulate more water vapor formation (which would then translate into more snowfall, increasing the overall snowpack). It's just too cold there to melt away.
     
  9. Paulie
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    Paulie Platinum Member

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    Would a huge piece of the ice shelf the size of Connecticut breaking off cause a problem?

    I'm admittedly not very knowledgable in this area. This sounds like the beginning of that movie Day After Tomorrow. I don't base my knowledge on movies, but in the movie that event was part of some pretty bad things to come.

    What do we make of this event?
     
  10. manifold
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    manifold Diamond Member

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    I make that it's worth keeping an eye on.

    IMO, concerns over global climate change are being addressed appropriately. I don't understand everyone's seeming need to pick one extreme or the other, especially when there isn't enough data to draw definitive conclusions, and the accuracy of the data that does exist is questionable. People seem to think either that it's humanity's greatest threat and we're all doomed if we don't take immediate, drastic action or that it's just a bunch of tree-hugging, enviro-fascist nonsense and we have nothing to worry about. I submit that prudence charts a course somewhere in between. Pay attention, continue to study the matter objectively and begin to formulate contingency options. Taking drastic action when it's completely unclear whether the action helps, worsens or does not influence a situation that may or may not be problematic, is hardly prudent...IMO. And of course sticking one's head in the sand and ignoring even the possibility that a problem exists is never prudent.
     

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