AS THE global debate for action on climate change rages, strong evidence is emerging that governments around the world have probably dodged another environmental bullet.
Human-induced ozone depletion, which once threatened massive disruption to life on Earth, is lessening on a global scale, the European Space Agency said yesterday.
''We found a global slightly positive trend of ozone increase of almost 1 per cent per decade in total ozone from the last 14 years,'' said Diego Loyola, of the German Aerospace Centre.
The finding comes as this year's Antarctic ozone hole appears set to level out below the worst 2006 benchmark, confirming predictions that repair is likely, though distant.
Destruction of the atmosphere's ozone layer in the 20th century was caused by the release of household chemicals, mainly chlorofluorocarbons. Ozone loss increased the risk of skin cancer, cataracts and harm to marine life from the sun's ultraviolet rays.
The damage, highlighted by the hole over Antarctica, was discovered in the early 1980s and governments agreed to ban the chemicals in the 1987 Montreal Protocol.
''[The Montreal Protocol] is to this day the world's most successful treaty, with every country on Earth signing on,'' said Roger Dargaville, a research fellow in climate change at Melbourne University.
The hole reached a maximum size of 27.4 million square kilometres on September 24, 2006. In the middle of this month it was about 25 million square kilometres, the World Meteorological Organisation said.
Dr Dargaville said it was too early to see a statistical trend in the size of the Antarctic hole, though there was every expectation that in the next 50 years or so it would repair.