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Study Finds Permafrost Thawing Quickly

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  • Mike Neuman
    Study Finds Permafrost Thawing Quickly By Larry O Hanlon, Discovery News Feb. 21, 2006 — A new study of the Arctic permafrost forecasts that global warming
    Message 1 of 1 , Mar 1, 2006
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      Study Finds Permafrost Thawing Quickly
      By Larry O'Hanlon, Discovery News

      Feb. 21, 2006 — A new study of the Arctic permafrost forecasts that
      global warming will thaw and shrink the total area of perennially
      frozen ground 60 to 90 percent by 2100.

      If true, it will increase the freshwater run-off into the Arctic
      Ocean by 28 percent, lead to the release by soils of vast doses of
      greenhouse gases, and upset ecosystems over wide areas.

      "This (projection) is definitely higher than other projections, both
      in area and depth," said David Lawrence, a climate modeler with the
      National Oceanic and Atmospheric Administration's Climate and Global
      Dynamics Division.

      Lawrence and Andrew Slater of the University of Colorado in Boulder
      published their permafrost projection in the February issue of
      Geophysical Research Letters.

      Currently in the Northern Hemisphere there are about four million
      square miles (10 million square kilometers) of land surface that does
      not thaw, even in the summer, which comes to about 24 percent of the
      land north of the equator.

      Lawrence and Slater incorporated into a computer climate model the
      current and projected rates of global warming, as well as the
      physical parameters of freezing and thawing of the upper 11 feet (3.5
      meters) of permafrost ground.

      They generated a broad-brush image of what might remain of the frozen
      ground by 2100. That image shows today's permafrost shrinking to
      between 400,000 and about two million square miles (one to four
      million square km).

      Put another way, the area of permafrost lost by 2100 could match or
      exceed the total land area of Australia.

      Thawing such a vast swath of northern lands means those soils will
      begin draining, moving more water to the sea, which raises sea levels
      and could wreak havoc with global weather patterns.

      It also means carbon that was frozen in the soils will be free to
      move up into the atmosphere in the form of the greenhouse gases
      carbon dioxide and methane, said Lawrence. This whole new source of
      greenhouse gases isn't something Earth needs right now.
      Other thawing consequences that are likely to reinforce warming, at
      least locally, include the colonization of newly thawed ground by
      Arctic shrubs.

      "Shrubs can deepen snow drifts and change in the timing of snow
      melting," said Lawrence. Generally, they speed-up the melting of
      snow, he said.

      Other researchers studying changes to permafrost don't see a lot to
      argue about in Lawrence and Slater's projection.

      "It's definitely an extreme (projection)," said Siberia permafrost
      expert Larry Smith of the University of California in Los
      Angeles. "But permafrost responds pretty quickly to thermal forcing.
      So I don't think it's out of line."
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