http://story.news.yahoo.com/news?tmpl=story&u=/nm/20030913/sc_nm/science_ozone_dc
Antarctic
Ozone Hole Biggest Ever
Fri Sep 12, 2003, 11:16 PM ET
By Jeremy Lovell
LONDON (Reuters) -
The gaping, man-made hole in the ozone layer over
Antarctica has hit record proportions for this time of year and
could
get bigger still within the next few days, a leading scientist
said Friday.
At just short of 10.81
million square miles, the hole is a fraction
under the absolute record of 11 million, but it has historically
peaked
in the second week in September and therefore could theoretically
grow
further, British Antarctic Survey (BAS) scientist Jonathan Shanklin
told Reuters.
"It was the largest
it has ever been during August, and we are waiting
to see what happens over the next few days," Shanklin told
Reuters
by telephone from BAS headquarters in Cambridge.
The stratospheric ozone
layer protects the earth's surface from
damaging ultraviolet rays that can cause skin cancer.
In 2002 the hole suddenly
shrank, raising hopes it had turned
the corner and was starting to close. But Shanklin said scientists
now believed this was an abnormality due to atmospheric conditions,
and that the 2003 expansion was back to more normal activity.
Shanklin said there
was no direct link between the hole and the
sharp rise in skin cancers worldwide, which he said was closely
linked to changing lifestyles. However, he said the general
thinning of the ozone layer elsewhere because of chemical depletion
was almost certainly involved in the rise.
Shanklin, one of the
scientists who first discovered the ozone hole
in 1985, said he and his colleagues were still at a loss to explain
exactly why it had got so big in August.
"The ozone hole
is continuously in motion. It is rather like a
spinning top," he said.
The 1985 discovery
forced a radical review and ultimately a complete
change in many industries that were belching ozone-depleting chemicals
into the atmosphere.
The consequent drop
in output of these chemicals began to bite
in 1994 and is now some 6 percent down on its peak.
However, the time lag
in the chemicals reaching the upper atmosphere
and attacking the key stratospheric ozone layer has meant that
the
benefits of the output reduction has taken several years to feed
through.
"We don't know
if the hole has finally peaked, is over the top and
on the way down or still has a bit further to go," Shanklin
said.
"We are sure that
we are pretty near the top, but we could have
to wait another decade to be able to say definitively that the
worst is over and it is starting to recover," he added.
Shanklin said it was
vital for countries to stick to the Montreal
Treaty curbing the emission of ozone depleting chemicals.
But he stressed that
until there was similar accord on greenhouse
gases it was impossible to tell what effect there would be on
the
atmosphere.
Most major polluting
nations have signed up to the Kyoto treaty
curbing carbon dioxide emissions. But the United States has refused,
even going so far as to refuse to accept that the gas is a pollutant.
"It would be excellent
if all countries in the world pulled together
on greenhouse gases," Shanklin said. "The discovery
of the ozone
hole proved we can change our atmosphere so easily. It was a big
surprise. There may well be further surprises in store for us."
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