Impacts of climate change on stratospheric ozone recovery

The impact of increasing greenhouse gases (GHGs) on the ``recovery'' of stratospheric ozone is examined using simulations of the Goddard Earth Observing System Chemistry-Climate Model. In this model, GHG-induced climate change has a large impact on the ozone evolution and when O-3 recovery milestones are reached. The two distinct milestones of O-3 returning to historical values'' and O-3 being no longer significantly influenced by ozone depleting substances (ODSs)'' can be reached at very different dates, and which occurs first varies between regions. GHG-induced cooling in the upper stratosphere causes O-3 to increase, and O-3 returns to 1980 or 1960 values several decades before O-3 is no longer significantly influenced by ODSs. In contrast, transport changes in the tropical and southern mid-latitude lower stratosphere cause O-3 to decrease. Here O-3 never returns to 1980 values, even when anthropogenic ODSs have been removed from the atmosphere. O-3 returning to 1960 ( or 1980) values should not necessarily be interpreted as O-3 recovery from the effects of ODSs. Citation: Waugh, D. W., L. Oman, S. R. Kawa, R. S. Stolarski, S. Pawson, A. R. Douglass, P. A. Newman, and J. E. Nielsen ( 2009), Impacts of climate change on stratospheric ozone recovery, Geophys. Res. Lett., 36, L03805, doi: 10.1029/2008GL036223.