Scientists from Environment Canada's Canadian Centre for Climate Modelling and Analysis have just published a new study on ozone depletion that has been selected as an American Geophysical Union "Research Spotlight," to be accompanied with an article in EOS - the American Geophysical Union weekly newspaper of the Earth and space sciences. The study is currently one of the most downloaded American Geophysical Union publications.

Using an atmosphere-ocean coupled general circulation model that allows for detailed calculations of stratospheric chemistry, the scientists simulated past and future changes in the Southern Ocean due to both greenhouse gases and ozone depleting substances. Their model calculations suggest that ozone depleting substances, which peaked in concentration in 1995, will be the dominant driver of changes in Southern Ocean circulation until the second quarter of the 21st century, at which point increasing greenhouse gas levels will take over. Further, they found that the peak impact of ozone depleting substances on the Southern Ocean circulation will occur a few decades after their peak concentration. The scientists suggest that future research needs to take into account the effects of ozone depletion, something that is not ordinarily done in investigations of Southern Ocean behaviour.

M. Sigmond, M. C. Reader, J. C. Fyfe, and N. P. Gillett (2011), Drivers of past and future Southern Ocean change: Stratospheric ozone versus greenhouse gas impacts, Geophys. Res. Lett., 38, L12601, doi:10.1029/2011GL047120.

Contact: John C. Fyfe, (250) 363-8236, Atmospheric Science and Technology Directorate