World climate can change in a hurry

Sept. 17, 2004 at 7:44 AM
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SANTA BARBARA, Calif., Sept. 16 (UPI) -- U.S. studies of ice sheets in the Antarctic indicate the Earth's climate can shift quite rapidly, a discovery important to the debate over global warming.

University of California, Santa Barbara, scientists studying chemical changes in deep sea sediments found cooling at high latitudes of the Southern Ocean increasingly isolated the Antarctic from tropical heat and moisture. The ocean warming was caused by shifts in the current triggered by changes in Earth's orbit.

With the warming influences of the equatorial regions reduced, the temperature of the Southern Ocean dropped about 7 degrees and the Antarctic ice sheets expanded quickly to near their current size.

The ice sheets are integral to the current climate of the planet. The fact the ice sheets can grow so quickly indicates fundamental changes, like orbital shifts or a rise in greenhouse gases, can trigger a rapid change in elements controlling the Earth's climate and therefore the climate itself.

To trace climate changes scientists measured chemical changes in the fossilized skeletal remains of marine plankton contained in deep-sea sediments.

The findings were published in Friday's issue of Science.

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