Ozone hole just got bigger this year

Washington, Oct 8 (IANS) The 2008 ozone hole - a thinning in the ozone layer over Antarctica - is larger both in size and ozone loss than 2007.

The ozone layer, 25 km above the earth, filters sunlight, shielding life on Earth from harmful ultraviolet rays which can increase the risk of skin cancer and cataracts and harm marine life.

This year the area of the thinned ozone layer over the South Pole reached about 27 million square km, compared to 25 million square km in 2007 and a record ozone hole extension of 29 million square kilometres in 2006, which is about the size of the North American continent.

The depletion of ozone is caused by extreme cold temperatures at high altitude and the presence of ozone-destructing gases in the atmosphere such as chlorine and bromine, originating from man-made products like chlorofluorocarbons (CFCs), which were phased out under the 1987 Montreal Protocol but continue to linger in the atmosphere.

Julian Meyer-Arnek of the German Aerospace Centre (DLR), which monitors the hole annually, explained the impact of regional meteorological conditions on the time and range of the ozone hole by comparing 2007 with 2008, said an European Space Agency press release.

'In 2007, a weaker meridional heat transport was responsible for colder temperatures in the stratosphere over the Antarctic, leading to an intensified formation of Polar Stratospheric Clouds (PSCs),' Meyer-Arnek said. 'Therefore, we saw a fast ozone hole formation in the beginning of September 2007.'