Spike in carbon dioxide emissions can cause mercury to rise

December 21st, 2009 - 2:03 pm ICT by IANS  

Washington, Dec 21 (IANS) Increases in atmospheric carbon dioxide could have a significantly larger effect on global temperatures than previously thought, says a new study.
A team of researchers demonstrated that only a relatively small rise in atmospheric carbon dioxide was associated with substantial warming during mid-and early-Pliocene era, three to five million years ago, when temperatures were approximately three to four degrees Celsius warmer than today.

Climate sensitivity - the mean global temperature response to a doubling of the concentration of atmospheric carbon dioxide - is estimated to be 1.5 to 4.5 degrees Celsius, using current models.

“These models take into account only relatively fast feedbacks, such as changes in atmospheric water vapour and the distribution of sea ice, clouds and aerosols,” said Mark Pagani, associate professor of geology and geophysics at Yale University, who led the study.

“We wanted to look at Earth-system climate sensitivity, which includes the effects of long-term feedbacks such as change in continental ice-sheets, terrestrial ecosystems and greenhouse gases other than carbon dioxide.”

Accordingly, the team focused on the most recent episode of sustained global warmth with geography similar to today’s, says a Yale release.

These findings appeared in the Sunday online edition of Nature Geoscience.

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