October 18, 2005

Antarctic ozone hole may have peaked, UN agency says

GENEVA (Reuters) - Depletion of the ozone layer above
Antarctica, caused by emissions of industrial chemicals, seems
to have peaked, indicating that global environmental pacts were
working, U.N. scientists said on Tuesday.

The seasonal hole above the South Pole and Antarctica is
now shrinking after falling short of the record years of 2003
and 2000, the United Nations' World Meteorological Organization
(WMO) said in its latest bulletin.

It peaked at 26.9 million sq kms on September 19, it said,
against 29 million sq km in September 2003, which most
scientists say was the record.

"It is the third largest ever, more or less as one would
expect from present levels of chlorine and bromine in the
atmosphere," Geir Braathen, WMO's top ozone expert, told a news

"It doesn't look as if the ozone hole is going to get any
bigger (in coming years). It seems like we have reached a
plateau...," he added.

Chlorofluorcarbons (CFCs) containing chlorine and bromine
are blamed for thinning the earth's protective layer -- which
filters harmful ultraviolet radiation that can cause skin
cancer and cataracts.

They were banned 20 years ago under the Vienna Convention
and its Montreal Protocol of 1987.

"As the amount of chlorine and bromine will continue to
decline over the next decades, but very slowly, one expects the
ozone hole to get smaller and smaller," Braathen said.

But uncertainties remained regarding the pace of the
ozone's recovery, according to the Norwegian expert.

"At the same time there is this issue of climate change
which will lead to higher temperature on the ground -- the
globe is warming up -- but in the stratosphere temperatures
will decrease. That will encourage more ozone loss in the
Arctic and the Antarctic," he added.