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Patagonian Glaciers Melting

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  • Mike Doran
    Scientists: Patagonian Glaciers Melting Mon Nov 17, 8:24 AM ET By ALEXA STANARD, Associated Press Writer BUENOS AIRES, Argentina - When Borge Ousland and
    Message 1 of 1 , Nov 18, 2003
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      Scientists: Patagonian Glaciers Melting
      Mon Nov 17, 8:24 AM ET


      By ALEXA STANARD, Associated Press Writer

      BUENOS AIRES, Argentina - When Borge Ousland and Thomas Ulrich
      trekked across the vast and wild Patagonian glaciers, they braved
      heavy snows and bitterly cold temperatures - nothing to make them
      think the ice was melting beneath their feet.



      "We had ... a lot of snow. We got a meter (3 feet) of snow in one
      night," said Ousland after the pair completed the 54-day crossing of
      the icefield.


      While the two European adventurers became the first to cross the
      icefields unaided on Oct. 16, a day later the glaciers made news of
      their own: A study published Oct. 17 in the journal Science found
      that the Patagonian glaciers melted at twice the rate in 1995-2000 -
      when compared with measurements from 1975 to 2000.


      Three top scientists used maps, satellite imagery and digital
      elevation models to measure the change in velocity of 63 Patagonian
      glaciers over 25 years.


      They found the glaciers are losing the equivalent of 10 cubic miles
      of ice every year - enough to raise the world's sea level an
      estimated four-one thousandths of an inch.


      The shrinking is reflective of rising global temperatures,
      scientists say, and is happening to glaciers around the world. As
      the melting causes sea levels to rise and freshwater supplies to
      disappear, scientists warn of potential worldwide economic and
      environmental disaster if the process isn't reversed.


      The biggest factor driving the thinning of Patagonia's glaciers is
      higher temperatures, said Eric Rignot of the National Aeronautics
      and Space Administration and one of the study's authors.


      But he said the glaciers themselves play a role as many are prone
      to "calving" - the process by which icebergs break off into
      surrounding oceans and lakes.


      "These types of glaciers are unstable, and more sensitive to climate
      change," Rignot said. "If the climate warms, they can go into a
      state of retreat. Once they start to advance, they do it quickly."


      Rignot was joined in the study by Andres Rivera of the University of
      Chile and Gino Casassa of that country's Center of Scientific
      Studies.


      They reported that the melting of the Patagonian icefields now
      accounts for 9 percent of annual global sea-level change from
      mountain glaciers.


      Located near the southernmost tip of South America, the Patagonian
      glaciers cover a remote region totaling 6,600 square miles. Enormous
      glaciers, some blinding white and others a deep blue, fill a rugged
      landscape of rivers, fjords and virgin pine forests.


      Some parts receive up to 100 feet of snow a year.


      Given the size of the Patagonian icefields, Rignot believes their
      research will help to understand how other large ice sheets, like
      those of Greenland and Antarctica, will respond to future climate
      change.


      Global temperatures have been warming steadily since the mid-1970s.
      Some temperature variation is normal, Rivera said, but the increases
      over the past thirty years are much higher than the natural
      variation observed before that time.


      Many scientists believe greenhouse gases, created by human activity,
      are the main cause of rising temperatures. But Rignot said
      scientists cannot be sure that human activity is causing glacier
      melt.


      "Glaciers are melting because it's warmer...," Rignot said. "Whether
      the cause of warming is from human activity or natural cycles, we
      can't say for sure."





      Higher temperatures, regardless of their cause, can wreak economic
      and environmental havoc, scientists say.

      "The glaciers are a symptom of a global malaise, rather like a fever
      might indicate that you have a virus," said Raymond Bradley,
      director of the Climate System Research Center at the University of
      Massachusetts.

      The Patagonian glaciers were hard to study in the past, Bradley
      said, but with NASA (news - web sites)'s new radar imaging
      technology, the glaciers are yielding information that confirms a
      worldwide phenomenon.

      "It turns out what is happening there is what is happening in other
      places, like Peru, Bolivia and Colombia - all of the high mountain
      glaciers are melting," Bradley added.

      In North America, similar changes have been noticed in glaciers in
      Washington state's Cascade mountains, Glacier National Park in
      Montana and Canada.

      Almost 80 percent of the ice on Mount Kilimanjaro in Kenya is gone,
      Bradley said. New Guinea's glaciers are vanishing, as is Arctic sea
      ice.

      "It's all part of the same phenomenon, which is global warming
      (news - web sites)," Bradley said.

      A glacier is an extended mass of ice that forms from snow
      accumulation over years and then moves slowly outward. As glaciers
      melt, they can form mountain lakes that can build up and suddenly
      burst through dams and flood surrounding areas, Rivera said.

      This has happened in Peru, Nepal and Alaska.

      Italy had a close call this past summer when a lake suddenly formed
      from melting ice in the Alps, threatening villages below and forcing
      the Italian army to pump water away.

      Still, many communities depend on glacier runoff for their
      freshwater supplies. Rignot said as glaciers shrink, those supplies
      are threatened.

      "If it rains, you have water," he said. "If it doesn't rain, you
      have no water."

      Rignot cited the near-total disappearance of the Chacaltaya glacier
      near La Paz, Bolivia, as an example. The city is scrambling to find
      new freshwater sources, he said. Peru and Ecuador face similar
      challenges.

      The process could reverse itself, albeit slowly, said Rivera.

      With decades of cooler temperatures, he said, the Patagonian
      glaciers could begin to expand again.

      If greenhouse gases are reduced, climate trends could start moving
      in the other direction. "If climate signals change in the future,
      glaciers will respond," Rivera said.

      The scientists hope their study draws attention to the need to
      protect the Patagonian icefields. "The region is amazing," Rivera
      said. "It's one of the most beautiful regions on Earth."



      Comment:

      The melting glaciers are actually Gaia's way of COOLING or feeding
      back less electro-mechanical feedbacks. What is occurring is less
      snow means less hydrology to the marine biosphere and shorter
      river/rainy season run off. As a consequence, the marine biosphere
      lacks nutrients, and hydrates lack weighing down sediments, and the
      result is a less conductive near shore boundry. Drought ensues.
      Fires burn and increase particles in the air which are lifeless--IOWs
      w/out specified charge and weight and size that feeds back optimal
      heat for convection. Fair weather conditions then persist along the
      ocean terresphere boundries and heat escapes to space.

      This is very consistant w/ the Eocine, where the microbial biosphere
      was dramatically depleted despite much "warmer" conditions.
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