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Ozone hole over Antarctica expands to near-record levels, now four times size of Australia

Ozone hole over Antarctica expands to near-record levels, now four times size of Australia, ABC News  The World Today , 3 Nov 15 By Lucy Carter The hole in the ozone layer over Antarctica has expanded to near-record levels this year, covering an area almost four times the size of Australia.

Scientists from the UN said the increase was due to colder-than-usual temperatures, rather than any extra damage being done to the Earth’s protective layer.

But that could still mean extra UV radiation and the risk of more people getting sunburnt in Australia’s southern states this summer.

The hole in the ozone layer above Antarctica has been carefully monitored for over 30 years.

According to atmospheric scientist Professor David Karoly from the University of Melbourne, its size fluctuates greatly when it emerges each spring. “Each springtime over the last now nearly 35 years, there’s been a depletion of stratospheric ozone over Antarctica primarily due to two really important factors,” he said.

“It’s the increase in ozone-depleting chemicals in the atmosphere and a very special cold conditions that occur in winter and spring over Antarctica which provide a special, if you like, catalytic ozone destruction vessel that allows the ozone to be rapidly deployed by the higher concentrations of chlorofluorocarbons — ozone-depleting chemicals that have occurred in the stratosphere due to human activity.”

The UN’s weather and climate agency said this year’s seasonal ozone hole peaked on October 2, covering an area over Antarctica of 28.2 million square kilometres — close to four times the size of Australia or the size of Russia and Canada combined…….

“We do know that the substances that cause the ozone hole, the chlorines and bromines up there are decreasing … have decreased by about 18 per cent since their peak in the late 1990s, early 2000s,” he said.

Since 1987, gases known to cause ozone depletion have been banned and last year the World Meteorological Organisation reported the first positive signs of “ozone recovery”.

Professor David Karoly from the University of Melbourne said this fluctuation in size was not a long-term concern.

“It makes it harder to then see the long-term improvement, the declining trend in the size of the ozone hole but that is still expected to continue,” he said.

“We expect in the southern hemisphere that the ozone hole will not completely recover for another 40 to 60 years, when it recovers back to pre-1980 levels when the ozone hole was first discovered.”

However, this year’s ozone hole size does have the potential to affect Australians.

“Once the ozone hole does start to break up, air that’s depleted in ozone may be transported over to the southern parts of Australia which can, of course, during those periods increase the amount of UV radiation which in the Earth’s surface,” Mr Krummel said.

“So there could be a tendency for a bit more sunburn. “I would say mostly the southern states is where it is likely to impact……..http://www.abc.net.au/news/2015-10-30/ozone-hole-over-antarctica-expands-to-near-record-levels/6898824

November 4, 2015 - Posted by Christina Macpherson | AUSTRALIA - NATIONAL, climate change - global warming