While sea ice extent has declined dramatically in the Arctic in recent years, it has increased slightly in the Antarctic. Some scientists have suggested that increased Antarctic sea ice extent can be explained by the ozone hole over Antarctica. Previous simulations have indicated that the ozone hole induces a large change in atmospheric circulation in austral summer and that this change in circulation could contribute to the changing Antarctic sea extent.
To learn more, M. Sigmond, of the Department of Physics at the University of Toronto, and J. C. Fyfe, of the Canadian Centre for Climate Modelling and Analysis, Environment Canada, used a climate model, forced by monthly varying observed stratospheric ozone changes from 1979 to 2005, to simulate the effects of stratospheric ozone depletion on Antarctic sea ice extent.
Contrary to predictions of previous studies, their model finds that ozone depletion would lead to a year-round decrease in Antarctic sea ice extent rather than the increase that was observed. The results suggest that processes other than ozone depletion must be causing the observed increase in Antarctic sea ice extent.
It remains unclear why Southern Hemisphere sea ice trends differ so greatly from Northern Hemisphere trends.
The research appears in the journal Geophysical Research Letters.
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