Breaking Earth News: Antarctica
Global Warming Alert
March 22, 2007
Photo: Ice on the surface of the southern ocean off the Antarctic coast is seen from the window of a U.S. military plane flying from Christchurch, New Zealand, to McMurdo Station, the biggest U.S. science base in Antarctica, in this December 7, 2006 file photo. The impact of global warming on the vast Southern Ocean around Antarctica is starting to pose a threat to ocean currents that distribute heat around the world, Australian scientists say, citing new deep-water data. (Deborah Zabarenko/Reuters)
HOBART (Reuters) - The impact of global warming on the vast Southern Ocean around Antarctica is starting to pose a threat to ocean currents that distribute heat around the world, Australian scientists say, citing new deep-water data.
Melting ice-sheets and glaciers in Antarctica are releasing fresh water, interfering with the formation of dense "bottom water," which sinks 4-5 kilometers to the ocean floor and helps drive the world's ocean circulation system.
A slowdown in the system known as "overturning circulation" would affect the way the ocean, which absorbs 85 percent of atmospheric heat, carries heat around the globe.
"If the water gets fresh enough ... then it won't matter how much ice we form, we won't be able to make this water cold and salty enough to sink," said Steve Rintoul, a senior scientist at the Australian government-funded CSIRO Marine Science.
"Changes would be felt ... around the globe," said Rintoul, who recently led a multinational team of scientists on an expedition to sample deep-basin water south of Western Australia to the Antarctic.
The Great Ocean Conveyor Belt: Abrupt Climate Change?
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