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Antarctica is not cooling after all

Scientists have long believed that Antarctica has been bucking the global warming trend, but that is not the case, new research shows.

East Antarctica, as assorted studies have shown, has been cooling recently, but the remainder of the continent is warming at a rate that offsets the cooling, according to satellite and ground data.

Global-warming skeptics have pointed to the presumed cooling of the continent as evidence that researchers’ computer projections of climate change are in error, but the new findings reported Thursday appear to refute their criticisms.

“We now see warming as taking place on all seven of the Earth’s continents in accord with what models predict as a response to greenhouse gases,” coauthor Eric J. Steig of the University of Washington said at a news conference about the report published in the journal Nature.

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Steig and his colleagues found that during the last 50 years temperatures for the entire continent rose an average of 0.2 degree Fahrenheit per decade, about the same as the rest of the world.

In West Antarctica, the average has been closer to 0.3 degree per decade. East Antarctica, which at an elevation of 10,000 feet is an average of 4,000 feet higher than the west, has warmed slightly over the half-century but has exhibited a cooling trend in recent decades.

Researchers attribute the cooling to the ozone hole that stretches over large sections of the region during the winter. The hole is caused by chlorofluorocarbons that have been released into the atmosphere, and it lets reflected sunlight escape to space.

The ozone-depleting chemicals have been banned, and researchers expect the ozone hole to be closed by the middle of this century. By that time, the continent should be warming at a much higher rate, Steig said.

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thomas.maugh@latimes.com


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