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2018-07-19. Greenhouse gases are warming the world—but chilling Antarctica. Here’s why.

posted Jul 22, 2018, 7:44 PM by Alan Gould
By Sid Perkins, Science Magazine. For GSS Climate Change chapter 4. Excerpt: The greenhouse gases that are warming the globe actually cool Antarctica much of the year, a new study confirms. The odd trend doesn’t break the laws of physics, but it does highlight what a strange place Earth’s southernmost continent truly is. Antarctica is home to many extremes. It’s the world’s highest continent, with an average elevation just a shade under 2300 meters. And despite its ice, it’s technically a desert thanks to a paucity of precipitation. This lack of moisture is one of the key factors behind the region’s “negative greenhouse effect,” says Sergio Sejas, an atmospheric scientist at NASA’s Langley Research Center in Hampton, Virginia, who led a newly published investigation of this atmospheric quirk. ...water vapor is a strong greenhouse gas, too. It is abundant in the atmosphere, giving it a much stronger overall warming effect. And when water vapor is scarce, as it is above central Antarctica, the continent’s greenhouse effect goes topsy-turvy, Sejas says. Add to it another weather phenomenon called a temperature inversion, where the atmosphere warms as altitude increases, rather than growing colder, and things truly start to go awry. ...“Antarctica is the only place in the world where the surface is colder than the stratosphere,” says Justus Notholt, an atmospheric physicist at the University of Bremen in Germany. The continent’s surface temperatures are typically 20°C colder than the temperature a few hundred meters up in the atmosphere, he explains.... http://www.sciencemag.org/news/2018/07/greenhouse-gases-are-warming-world-chilling-antarctica-here-s-why
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