Ozone Layer Suffers Record Loss
HUFFINGTONPOST.COM - The protective ozone layer in the Arctic that keeps out the sun's most damaging rays – ultraviolet radiation – has thinned about 40 percent this winter, a record drop, the U.N. weather agency said Tuesday.
The Arctic's damaged stratospheric ozone layer isn't the best known "ozone hole" – that would be Antarctica's, which forms when sunlight returns in spring there each year. But the Arctic's situation is due to similar causes: ozone-munching compounds in air pollutants that are chemically triggered by a combination of extremely cold temperatures and sunlight.
The losses this winter in the Arctic's fragile ozone atmospheric layer strongly exceeded the previous seasonal loss of about 30 percent, the U.N.'s World Meteorological Organization in Geneva said.
It blamed the combination of very cold temperatures in the stratosphere, the second major layer of the Earth's atmosphere, just above the troposphere, and ozone-eating CFCs from aerosol sprays and refrigeration.
"This is pretty sudden and unusual," said Bryan Johnson, an atmospheric chemist who works in the U.S. National Oceanic and Atmospheric Administration's Earth System Laboratory in Boulder, Colorado.
Atmospheric scientists concerned about global warming focus on the Arctic because that is a region where the effects are expected to be felt first.
"The Arctic stratosphere continues to be vulnerable to ozone destruction caused by ozone-depleting substances linked to human activities," the U.N. weather agency's secretary-general Michel Jarraud said.
Although the thinner ozone means more radiation can hit Earth's surface, the ozone levels in the Arctic remain higher than in other regions such as in the equatorial regions, said the National Oceanic and Atmospheric Administration, whose recent Arctic findings mirror those of the U.N. agency.
Ozone losses occur over the polar regions when temperatures drop below -78 degrees Celsius (-108 Fahrenheit) and iridescent ice clouds form. Sunlight on icy surfaces triggers the ozone-eating reactions in chlorine and bromine that comes from air pollutants such as chlorofluorocarbons, or CFCs, once widely used as refrigerants and flame retardants in household appliances.
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