Ozone layer thins 40% in Arctic
Tue, 05 Apr 2011 17:58:28 GMT
The protective ozone layer in the Arctic has thinned about 40 percent this winter, marking a record drop, the UN weather agency says.
The Arctic's damaged stratospheric ozone layer is different with the best known "ozone hole" in the Antarctica, which is formed when sunlight returns in spring there each year, reports the Associated Press.
But the Arctic's situation is due to similar causes: ozone-munching compounds in air pollutants that are chemically trigged by a combination of extremely cold temperatures and sunlight.
The Ozone layer protects against skin cancer by keeping out the sun's most damaging rays -- ultraviolet radiation.
The losses this winter in the Arctic's fragile ozone atmospheric layer strongly exceeded the previous seasonal loss of about 30 percent, the UN 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 US 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 UN weather agency's secretary-general Michel Jarraud said.