Friday, September 28, 2007

Ozone Hole Science Revisited

I thought I was confused (see "What Planet is the U.N. living On and How to Make a Buck by Answering Correctly") last week.

Now Ron Baily authors this for Reason:

Scientists are commemorating the discovery 20 years ago that man-made chlorofluorocarbons (CFCs) used chiefly in refrigerators and air-conditioners were responsible for creating the "ozone hole" over the Antarctic. The scientists concluded that CFCs would drift into the stratosphere where they would produce chlorine compounds that react with ice particles and sunlight to efficiently destroy ozone molecules that shield the surface from ultraviolet light streaming from the sun. In 1987, the world adopted the Montreal Protocol to eventually eliminate the production of CFCs. Activists often cite the Montreal Protocol as a model for a future treaty addressing man-made global warming by banning the emission of greenhouse gases. A Nobel Prize in chemistry was awarded in 1995 to the three scientists who identified the ozone/CFC connection.

This neat story of the scientific identification of a man-made cause for stratospheric ozone depletion followed by a successful international response to the threat is now being challenged by some very recent research. (sub required) is reporting a new analysis by Markus Rex, an atmosphere scientist at the Alfred Wegener Institute of Polar and Marine Research in Potsdam, Germany, which finds that the data for the break-down rate of a crucial molecule, dichlorine peroxide (Cl2O2) is almost an order of magnitude lower than the currently accepted rate.

What this could mean according to the Nature news article is that:

"This must have far-reaching consequences," Rex says. "If the measurements are correct we can basically no longer say we understand how ozone holes come into being." What effect the results have on projections of the speed or extent of ozone depletion remains unclear....MORE