Hole in ozone layer bigger

By ANNE BESTON environment reporter

This year's giant-sized ozone hole has put paid to any hopes of a slowdown in the annual thinning in the ozone layer above Antarctica.

The ozone hole that began forming last month is bigger than last year's, reaching 27 million sq km in the second week of this month.

But scientists do not yet know whether it will break the record set in 2000, when the hole reached 28 million sq km, four times the size of Australia.

Last year's smaller ozone hole of 25 million sq km was due to meteorological conditions and not the result of bans on ozone-depleting chemicals, scientists say.

Dr Alan Rodger, of the British Antarctic Survey, said it would be at least a decade before they could say with certainty that lower levels of CFCs were having an effect.

"Last year's hole should clearly be regarded as a one-off event in the record so far," he said.

Scientists discovered in the mid-1970s that chlorofluorocarbons (CFCs) - synthetic chemicals found in aerosols, refrigeration coolants and air-conditioning - were depleting the ozone layer.

Ozone forms a protective shield above the Earth's surface, blocking the sun's harmful UV-B rays.

Southern Hemisphere inhabitants are exposed to higher levels of UV rays that can cause skin cancer, eye cataracts and affect immunity.

Ozone depletion

* Can mean higher risk of skin cancer, eye cataracts and severe sunburn, wrinkles, liver spots.

* Exposure to UV rays can damage skin, lowering resistance to infectious diseases and skin tumours.

* Can cause environmental damage to animals and plants - including phytoplankton and microscopic plants in lakes and oceans which form the base foundation of the marine food chain.