Ever Growing Ozone hole reappears over Antarctic: WMO
Pastor Dale Morgan
Ever Growing Ozone hole reappears over Antarctic: WMO*
GENEVA, Sept 12 (AFP) Sep 12, 2007
The hole in the protective ozone layer over the Antarctic is forming
again eclipsing the record size it reached last year, a scientist at the
UN's weather agency said Wednesday.
The gap in the ozone in the upper atmosphere, at altitudes of up to 25
kilometres (15 miles), has reached a size of about 23 million square
kilometres (8.9 million square miles), said World Meteorological
Organisation ozone expert Geir Braathen.
In 2006, the hole covered an area of 29.5 million square kilometres
(11.39 million square miles), exceeding the previous record set six
years earlier.
"This year, the temperature in the stratosphere is a little less cold
than in 2006. It's therefore possible that the hole might be a little
smaller," Braathen told AFP.
Stratospheric ozone provides a natural protective filter against harmful
ultra violet rays from the sun, which can cause sunburn, cataracts, skin
cancers and damage vegetation.
Its depletion is caused by extreme cold temperatures at high altitude
and a particular type of pollution, from chemicals often used in
refrigeration, some plastic foams, or aerosol sprays, which have
accumulated in the atmosphere.
Most of the chemicals, chloroflurocarbons (CFC), are being phased out
under the 1987 Montreal Protocol, but they linger in the atmosphere for
many years.
The hole in the layer over the Antarctic was discovered in the 1980s. It
regularly tends to form in August before it fills again in mid-December.
Countries taking part in the Montreal Protocol are expected to have
tough discussions next week about phasing out another class of
ozone-harming chemical, HCFCs, which are used as refrigerants in some
air conditioning units, Braathen said.
The meeting in Montreal, Canada, will follow World Ozone Day on
September 16, marking 20 years since the treaty was signed.