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Modeling of long-term fossil fuel consumption shows 14.5 degree hike

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    Fw: [fuelcell-energy] ... in temperature Modeling of long-term fossil fuel consumption shows 14.5 degree hike in temperature If humans continue to use fossil
    Message 1 of 1 , Dec 8, 2005
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      in temperature

      Modeling of long-term fossil fuel consumption shows 14.5 degree hike
      in temperature

      If humans continue to use fossil fuels in a business as usual manner
      for the next several centuries, the polar ice caps will be depleted,
      ocean sea levels will rise by seven meters and median air
      temperatures will soar 14.5 degrees warmer than current day.

      These are the stunning results of climate and carbon cycle model
      simulations conducted by scientists at the Lawrence Livermore
      National Laboratory. By using a coupled climate and carbon cycle
      model to look at global climate and carbon cycle changes, the
      scientists found that the earth would warm by 8 degrees Celsius (14.5
      degrees Fahrenheit) if humans use the entire planet's available
      fossil fuels by the year 2300.

      The jump in temperature would have alarming consequences for the
      polar ice caps and the ocean, said lead author Govindasamy Bala of
      the Laboratory's Energy and Environment Directorate. .

      In the polar regions alone, the temperature would spike more than 20
      degrees Celsius, forcing the land in the region to change from ice
      and tundra to boreal forests.

      "The temperature estimate is actually conservative because the model
      didn't take into consideration changing land use such as
      deforestation and build out of cities into outlying wilderness
      areas," Bala said.

      Today's level of atmospheric carbon dioxide is 380 parts per million
      (ppm). By the year 2300, the model predicts that amount would nearly
      quadruple to 1,423 ppm.

      In the simulations, soil and living biomass are net carbon sinks,
      which would extract a significant amount of carbon dioxide that
      otherwise, would be remaining in the atmosphere from the burning of
      fossil fuels. However, the real scenario might be a bit different.

      "The land ecosystem would not take up as much carbon dioxide as the
      model assumes," Bala said. "In fact in the model, it takes up much
      more carbon than it would in the real world because the model did not
      have nitrogen/nutrient limitations to uptake. We also didn't take
      into account land use changes, such as the clearing of forests."

      The model shows that ocean uptake of CO2 begins to decrease in the
      22nd and 23rd centuries due to the warming of the ocean surface that
      drives CO2 fluctuations out of the ocean. It takes longer for the
      ocean to absorb CO2 than biomass and soil.

      By the year 2300, about 38 percent and 17 percent of the carbon
      dioxide released from the burning of all fossil fuels are taken up by
      land and the ocean, respectively. The remaining 45 percent stays in
      the atmosphere.

      Whether carbon dioxide is released in the atmosphere or the ocean,
      eventually about 80 percent of the carbon dioxide will end up in the
      ocean in a form that will make the ocean more acidic. While the
      carbon dioxide is in the atmosphere, it could produce adverse climate
      change. When it enters the ocean, the acidification could be harmful
      to marine life.

      The models predict quite a drastic change not only in the temperature
      of the oceans but also in its acidity content, that would become
      especially harmful for marine organisms with shells and skeletal
      material made out of calcium carbonate.

      Calcium carbonate organisms, such as coral, serve as climate-
      stabilizers. When the organisms die, their carbonate shells and
      skeletons settle to the ocean floor, where some dissolve and some are
      buried in sediments. These deposits help regulate the chemistry of
      the ocean and the amount of carbon dioxide in the atmosphere.
      However, earlier Livermore research found that unrestrained release
      of fossil-fuel carbon dioxide to the atmosphere could threaten
      extinction for these climate-stabilizing marine organisms.

      "The doubled-CO2 climate that scientists have warned about for
      decades is beginning to look like a goal we might attain if we work
      hard to limit CO2 emissions, rather than the terrible outcome that
      might occur if we do nothing," said Ken Caldeira, of the Department
      of Global Ecology at the Carnegie Institution and one of the other

      Bala said the most drastic changes during the 300-year period would
      be during the 22nd century in which precipitation change, an increase
      in atmospheric precipitable water and a decrease in sea ice size are
      the largest when emissions rates are the highest. During the model
      runs, sea ice cover disappears almost completely in the northern
      hemisphere by the year 2150 during northern hemisphere summers.

      "We took a very holistic view," Bala said. "What if we burn
      everything? It will be a wake up call in climate change."

      As for the global warming skeptics, Bala said the proof is already

      "Even if people don't believe in it today, the evidence will be there
      in 20 years," he said. "These are long-term problems."

      He pointed to the 2003 European heat wave, and the 2005 Atlantic
      hurricane season as examples of extreme climate change.

      "We definitely know we are going to warm over the next 300 years," he
      said. "In reality, we may be worse off than we predict."

      Other Livermore authors include Arthur Mirin and Michael Wickett, and
      Christine Delire of ISE-M at the Universit´┐Ż Montepellier II

      Weitere Informationen: www.llnl.gov/PAO




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