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Ancient shells tell tale of climate change

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  • npat1
    Ancient shells tell tale of climate changeWed Sep 12, 2007 By knowing the age of the marine fossil and measuring the concentration of these
    Message 1 of 1 , Sep 12, 2007
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      Ancient shells tell tale of climate change

      Wed Sep 12, 2007

      <blockquote>

      By knowing the age of the marine fossil and measuring the concentration of these isotopes, the scientists can tell the temperature of the seawater in which they lived.

      "The shell is the thermometer," said John Eiler, a Caltech professor of geochemistry who worked on the study.

      ...

      They studied fossils from the Silurian period about 400 million years ago, during which carbon dioxide levels are believed to have been 10 times higher than at present.

      They compared these with fossil temperature readings in the Carboniferous period, roughly 300 million years ago, during which atmospheric carbon dioxide concentrations are thought to have resembled current levels.

      "Our study found that in fact there was a huge temperature change -- that the time of high carbon dioxide was a time of quite high temperature in tropical oceans, about 34 degrees centigrade (93 F)," Eiler said. "If you got in it, you would think it was a pretty warm bath."

       

      Based on this finding, the researchers believe they have fossil evidence that changes in atmospheric carbon dioxide are associated with changes in temperature.

      "It shows that carbon dioxide has been a powerful driver of climate change in the Earth's past," Eiler said.

      </blockquote>

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      http://uk.reuters.com/article/environmentNews/idUKN1226664120070912

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