MercoPress. South Atlantic News Agency

Late starter 2008 ozone layer shaping to be a record

This year's ozone hole surrounding the Southern Hemisphere's pole is shaping up to be one of the largest ever, having already surpassed the size of last year's, according to the World Meteorological Organization.

WMO says that despite a relatively late start, the ozone hole has grown rapidly during the past couple of weeks and has now passed the maximum size attained in 2007. According to WMO the hole in the ozone layer over Antarctica currently covers an area of 27 million square kilometers, compared to a maximum of 25 million square kilometers last year. It says that while the hole continues to grow, it is still too early to determine how large it will be, before it breaks apart in mid-December. Paul Fraser, an atmospheric scientist with Australia's Commonwealth Scientific and Industrial Research Organization, says that while this year's ozone hole is large, it isn't unexpected. "Last year's hole was relatively small," says Fraser. "Most of the holes over the past few years have been large". He added that, "This year's hole is shaping up to be a big one like 2006, which was one of the biggest". The hole in the ozone layer over Antarctica in 2006 measured 28 million square kilometers. Ozone-depleting chemicals, such as chlorofluorocarbons, were phased out under the 1987 Montreal Protocol, but continue to linger in the atmosphere. "The size is driven largely by the temperature and shape of the polar vortex ? the air mass in the stratosphere in which the ozone hole forms" says Fraser. "When it's exceptionally cold and symmetrical then you'll have a very deep ozone hole." Experts predict that the ozone layer will fully recover sometime in the second half of this century, but this is complicated by other atmospheric processes, such as an increase in the level of greenhouse gases. September 16 has been designated by the United Nations as International Day for the Preservation of the Ozone Layer, in coincidence with the signing in 1987 of the Montreal Protocol on Substances that Deplete the Ozone Layer.