Reports
Submitted on December 10, 2007
Accepted on April 9, 2008

The Sensitivity of Polar Ozone Depletion to Proposed Geoengineering Schemes
Simone Tilmes 1*, Rolf Müller 2, Ross Salawitch 3
1 National Center for Atmospheric Research, Boulder, CO 80307, USA.
2 Research Center Jülich, 52425 Jülich, Germany.
3 University of Maryland, College Park, MD 20742, USA.

* To whom correspondence should be addressed.
Simone Tilmes , E-mail: tilmes@ucar.edu

The large burden of sulfate aerosols injected into the stratosphere by the eruption of Mt. Pinatubo in 1991 cooled our planet and enhanced destruction of polar ozone in the following few years. The continuous injection of sulfur into the stratosphere has been suggested as a "geoengineering" scheme to counteract global warming. We use an empirical relationship between ozone depletion and chlorine activation to estimate how this approach might influence polar ozone. An injection of sulfur large enough to compensate surface warming due to the doubling of CO2 would cause a drastic increase in the extent of Arctic ozone depletion during the next century for cold winters and would cause a considerable delay, between 30 and 70 years, in the expected recovery of the Antarctic ozone hole.

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