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    Article Last Updated: ? ... Study: Global future bleak Severe climate changes will create a very different Earth, scientists say By Ian Hoffman, STAFF WRITER
    Message 1 of 1 , Nov 4, 2005
      Article Last Updated: ?
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      Study: Global future bleak
      Severe climate changes will create a very different Earth, scientists
      By Ian Hoffman, STAFF WRITER
      Inside Bay Area

      If humanity taps all known oil, gas and coal reserves for energy,
      plants and oceans will have trouble absorbing the growing carbon
      dioxide in the atmosphere, and temperatures will soar beyond current
      projections, virtually eliminating tundra, sea ice and cold climate
      forests, according to a study by Lawrence Livermore Lab researchers.
      Scientists there asked supercomputers to simulate the complete
      burnout of all fossil fuels and the resulting changes in climate
      through 2300, two centuries longer than almost any other climate

      What they found was a dramatically changed world, with temperatures
      rising an average of 14.5 degrees worldwide and 68 degrees or more in
      polar regions.

      Bala Govindasamy, a Livermore atmospheric scientist and lead author
      of the study, said the simulation is highly conservative: It probably
      overestimates the ability of plants to absorb carbon dioxide and so
      underestimates the climate change.

      "So the reality may be worse," he said. "We may not have seen the
      climate change today, but if we continue to emit fossil fuels as
      usual, I think we are headed for real severe climate consequences,
      and the sooner we take action, the better."

      The greatest warming occurs in the next century, beyond the time
      frame for most climate projections, when carbon dioxide levels in the
      atmosphere reach 1,000 parts per million, or nearly four times pre-
      industrial concentrations, in about 2140, then peak in 2300 at

      1,438 parts per million.

      Scientists are uncertain how well societies can adapt to a doubling
      or tripling of carbon dioxide, but there is growing consensus that a
      quadrupling would pose major challenges.

      "We don't even want to get close to 1,000," said physicist Steven
      Chu, director of Lawrence Berkeley National Laboratory. "That's a

      Such a scenario could come sooner than Livermore's simulation
      indicates. The model is highly sophisticated, a product of one of
      only about a half-dozen research teams worldwide that have built a
      full representation of the Earth's climate, soils, vegetation and

      "The ecosystems actually move," Govindasamy said. "The land ice in
      the arctic completely disappears, and the tundra basically

      What takes its place are trees, not boreal forests, which retreat to
      only northern Siberia and Greenland, but expanding tropical and
      temperate forests that are fertilized by all the extra carbon dioxide
      in the air. Later this century especially, the model says trees are
      growing wildly and absorbing a large amount of carbon dioxide, as are
      the oceans.

      But the model assumes unlimited nutrients in the soil to feed all
      that growth.

      "At some point, the plants tend to run out of something else they
      need, either nitrogen or water," said Scott Doney, an atmospheric
      scientist at Woods Hole Oceanographic Institute who is developing a
      similar full, Earth system model with Inez Fung, a leading climate
      researcher at the University of California, Berkeley.

      If plant growth is limited as temperatures rise and the tropics
      become drier, then large tropical forests could die off and release
      their stored carbon dioxide to the atmosphere. The same could happen
      if peat deposits in tundra get both warm and dry, or if vegetation
      worldwide becomes dry enough for fires to release their carbon.

      If any of those occur, climate change will occur faster. If not, the
      absorption of carbon dioxide by the land and the oceans drops off
      anyway. Doney said the Livermore study "gives a sense of how bad the
      climate change could be" if humanity doesn't find new, cleaner energy

      "The Earth is not going to clean up the carbon mess for us," he
      said. "We're going to have to do it or live with the consequences."

      Contact Ian Hoffman at ihoffman@...




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