NASA Finds First-ever Ozone Hole Over Arctic
October 10, 2011
By Pat Brennan, The Orange County Register
The first ozone "hole" ever seen over northern polar regions was picked up earlier this year by satellites and weather balloons, according to a new study led by NASA.
The severe depletion of the ozone layer, which shields Earth from harmful ultraviolet rays, was comparable to the ozone hole seen each year over the Antarctic since the mid 1980s, though smaller.
"We`ve had severe ozone loss in previous Arctic winters," said Michelle L. Santee of Jet Propulsion Laboratory in Pasadena, one of the authors of the study. "But this was the first time the extent and magnitude of the loss could reasonably be described as a hole."
The cause for both the Arctic and Antarctic ozone holes is the same, the study says: unusually cold conditions that convert chemicals produced by humans into ozone-gobbling forms of chlorine.
Although the release of ozone-depleting substances was limited by the 1989 Montreal Protocol, scientists say the long lifetimes of such chemicals once in the atmosphere will ensure Antarctic ozone holes for decades to come.
They also could bring more episodes of severe depletion over the Arctic - where we likely would be seeing yearly ozone holes already if the protocol had not been enacted.
"It may be decades before we see another winter as cold as this one," Santee said. "On the other hand, it could be this cold next year."
Scientists from nine countries took part in the study, which revealed a cold period during the 2011 Arctic winter and spring lasting 30 days longer than any previously measured.
While loss of ozone happens every year over the Arctic, warmer air in the upper atmosphere usually keeps the time-frame for ozone-destroying reactions to a minimum.
Winter temperatures in 2011 were no colder in the Arctic than they have been in other years, the scientists said. The difference was the longer window for ozone-destroying reactions to occur.
And while the Arctic ozone hole was about 40 percent smaller than Antarctica`s, and did not last as long, it was also more mobile, sometimes showing up over populated areas. Those included Russia and central Asia, Santee said, although that was not part of the study.
Depletion of ozone in the upper atmosphere allows more ultraviolet radiation from the sun to reach the surface, potentially causing an increase in skin cancer and other health problems.
The study was published Oct. 2 in the science journal, Nature (http://www.nature.com).
(c)2011 The Orange County Register (Santa Ana, Calif.) Distributed by Mclatchy-Tribune News Service.
Story image: This NASA image shows the large ozone hole that opened up this sping over the Arctic. Photo: AFP/NASA/JPL.
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