LIkely Date For Antarctic Ozone Repair Now Set At 2065 - Nature

The Antarctic ozone hole will probably take longer to heal than was previously thought, scientists say. At the current rate of recovery, the hole won't be gone until around the year 2065, some 15 years later than the generally accepted estimate.

Research to monitor the worldwide amount of chlorofluorocarbon chemicals, or CFCs, which eat away at the protective ozone layer when released into the atmosphere, suggests that more of the chemicals are out there than expected. Modelling studies also indicate the hole will take a while to disappear.

"We're looking now at a time frame of something like 2065," said John Austin, a computer modeller at the Geophysical Fluid Dynamics Laboratory in Princeton, New Jersey. He and his colleagues from several different research teams presented their ozone results on 6 December at the American Geophysical Union meeting in San Francisco.

Production of CFCs was essentially banned under the 1987 Montreal Protocol. But some linger on in old refrigerators, fire extinguishers, air-conditioning systems and other equipment. Eventually, those chemicals will be released into the atmosphere to wreak their ozone-destroying reactions, said Dale Hurst of the National Oceanic and Atmospheric Administration's Global Monitoring Division in Boulder, Colorado, also speaking on 6 December at the meeting.

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http://www.nature.com/news/2005/051205/full/051205-9.html