Wednesday, February 25, 2009

Atmospheric CO2 Could Last A Millenium

Until recently it was thought that CO2 emitted into the atmosphere lasted maybe a century or two before it was reabsorbed either into the sea or plant life or some other sink. From McClatchey Newspapers:

David Archer, a leading climate researcher who teaches at the University of Chicago, has written a new book that looks at carbon dioxide's "long tail" and what it means for changes on Earth in the future.

If the world continues its heavy use of coal over the next couple of hundred years until it's essentially used up, it would take several centuries more for the oceans to absorb about three-quarters of the carbon dioxide emitted into the atmosphere. In those centuries, there would be a "climate storm" that Archer says would be significantly worse than the forecast from now to 2100.

The remaining carbon dioxide — the long tail — would stay in the atmosphere for thousands of years, leaving a warmer climate. About 10 percent of it would still be in the atmosphere in 100,000 years, Archer wrote in "The Long Thaw: How Humans Are Changing the Next 100,000 Years of Earth's Climate."

Because of the long life of CO2 from fossil fuels, the climate impacts would last for many thousands of years. Ice sheets would melt, raising seas high enough to swamp 10 percent or more of the world's agricultural land. Other climate impacts could include uncomfortable heat and drier continental interiors, Archer tells his readers. "In the long run, it could be a steep price to pay for a century or so of fossil fuel energy."

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