Geneva - Climate change posed a real threat to saving the ozone layer, the UN weather agency warned ahead of the anniversary of the Montreal Protocol to prevent ozone depletion. The protocol agreed to ban the harmful substances, chlorofluorocarbons, CFCs, that destroy the Earth's protective ozone layer. The World Meteorological Organization, WMO, said greater vigilance would be needed even as those substances broadly peaked and started to decline.
"Global changes in climate mean that conditions in the atmosphere are different today from those that prevailed prior to periods marked by ozone depletion. The changes in conditions may indeed have implications for ozone recovery," said WMO Secretary-General Michel Jarraud late on Friday.
He spoke in Geneva to mark the 20th anniversary of the signing of the Protocol on September 16 1987, which followed the 1985 Vienna Convention.
"Over the next ten to twenty years, high quality global observations of ozone and ozone-depleting substances will be particularly critical in verifying the effectiveness of the actions taken under the Vienna Convention in 1985, the Montreal Protocol of 1987 and its amendments and adjustments," he added.
It was vital to be able to separate effects due to climate change and those due to ozone-depleting substances.
Scientists believe greenhouse gases cool the atmosphere at altitude creating conditions that accelerate ozone depletion. They believe climate change may offset gains so far in controlling CFC's found in hairsprays and fridges.
According to WMO, the ozone layer which filters the dangerous effects of the ultraviolet rays that can cause skin cancer, continues to be depleted particularly over the Antarctic region.
The Antarctic hole reached a record size in 2006 spanning 29.5 million square kilometres. WMO said it was still too early to determine how large this year's ozone hole would be.
The Montreal Protocol, signed by 24 states, was hailed by UN Secretary-General Ban Ki-moon as "one of the great success stories of international cooperation," in a statement Thursday.
Up to 191 governments are due to meet in Montreal for five days starting Sunday. There is pressure to scale up action on remaining CFC's and also on hydrochlorofluorocarbons, HCFCs, a replacement compound now regarded as equally harmful by some scientists.
