13.5 The Ozone Hole and Southern Hemisphere Climate Change

Friday, 12 June 2009: 11:40 AM
Pinnacle A (Stoweflake Resort and Confernce Center)
Seok-woo Son, McGill University, Montreal, QC, Canada; and N. Tandon, L. M. Polvani, and D. Waugh

Climate change in the Southern Hemisphere (SH) has been robustly documented in the last several years. It has altered the atmospheric circulation in a surprising number of ways: a rising global tropopause, a poleward intensification of the westerly jet, a poleward shift in storm tracks, a poleward expansion of the Hadley cell, and many others. While these changes have been extensively related with anthropogenic warming resulting from the increase in greenhouse gases, their potential link to stratospheric cooling resulting from ozone depletion remains tentative, and a comprehensive picture the polar ozone's role in the SH climate system is still lacking. Examining model output from the coupled climate models participating in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment (AR4), and grouping them depending on the stratospheric ozone forcing used, we here show that stratospheric ozone affects the entire atmospheric circulation in the SH, from the polar regions to the subtropics, and from the stratosphere to the surface. Furthermore, model projections suggest that the anticipated ozone recovery, resulting from the implementation of the Montreal Protocol, will likely decelerate future climate change resulting from the increased greenhouse gases, although it might accelerate surface warming over Antarctica.
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