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Fw: [CCG] Possible runaway greenhouse effect caused mega-extinction e vent @ end of Permian

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  • npat1
    ... http://www.enn.com/today.html?id=10206 Expert Says It Was Hotter 247 Million Years Ago April 05, 2006 — By Associated Press CAVE JUNCTION, Ore. — John
    Message 1 of 1 , Apr 6, 2006
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      http://www.enn.com/today.html?id=10206

      Expert Says It Was Hotter 247 Million Years Ago

      April 05, 2006 � By Associated Press

      CAVE JUNCTION, Ore. � John Roth shined his flashlight on a black
      streak flowing through the cream-colored marble forming the walls of
      the Oregon Caves.

      The graphite line is graphic evidence of dramatic global warming that
      consumed so much oxygen that it nearly wiped out all life on the
      planet 247 million years ago, said the natural resources specialist
      for the Oregon Caves National Monument.

      "It was the biggest extinction by far of all time," he said.
      "Geologists and paleontologists all agree on that. ... The extinction
      that killed the dinosaurs about 65 million years ago, that wasn't
      anything compared to this."

      Yet, like the huge meteor striking the Gulf of Mexico that many
      scientists believe wiped out the dinosaurs, the global warming at the
      end of the Permian period resulted in deadly amounts of carbon dioxide
      that killed most land animals, he said.

      Scientists aren't certain what caused the episode some 247 million
      years ago. They estimate that temperatures ranged in the low 100s
      year-round for thousands of years, he said.

      "Its kind of scary that we don't know for sure what caused the worst
      catastrophe of life on this planet," he said.

      The graphite lines, whose significance was recently recognized, are
      not unique to the caves, which were formed perhaps half a million
      years ago, he said.

      Roth is a geologist by training and a former science teacher who has
      worked as a natural resource specialist at the monument for 17 years.

      He said the new evidence suggests that "we had a runaway hothouse
      effect because of the excess carbon dioxide. There was so much carbon
      dioxide introduced into the atmosphere, mostly from methane from the
      oceans."

      That carbon dioxide build-up alone would have killed off most
      oxygen-breathing species, he said.

      Source: Associated Press

      -Ross mayhew.
      http://groups.yahoo.com/group/ClimateConcern/
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