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Australian report: 50 years to close ozone hole
Wed,
Sep. 18, 2002 2:21 PM ET
By the Associated Press
SYDNEY,
Australia (AP) -- Chlorine-based chemical levels in the
atmosphere are falling, and the hole in the ozone layer over
Antarctica should close within 50 years, according to an
Australian government-funded study.
CSIRO
atmospheric monitoring has found that chlorine from
chlorofluorocarbons, or CFCs, leveled off in the troposphere
-- the lower atmosphere -- two years ago, and is falling for
the first time in more than 20 years. The ozone layer over the
southern continent of Antarctica has suffered the most damage
from CFCs, which have eaten a hole about 10 million square
miles. The hole is about three times the size of Australia.
Scientists
expect the chlorine decrease will lead to a gradual recovery
of the ozone layer during the next half century. In turn, the
ozone recovery will decrease the risk of skin cancer and
similar ailments in the far southern hemisphere, where damage
to the protective layer of gas is most serious. The ozone
recovery will not alleviate projected global warming problems,
however, which is related to the release of other
heat-trapping gases into the atmosphere.
CFCs
were banned in the developed world in the mid-1990s after a
pact signed at a 1989 international conference in Montreal,
Canada. They are still being phased out in developing
countries. The prohibition of CFCs -- which were used in
refrigerators, air conditioners and aerosol spray cans -- came
after it was found they were breaking up the earth's ozone, a
thin layer of atmosphere that filters the sun's damaging
ultraviolet rays and protects humans from skin
cancer.
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Spring + UV rays = Sun Safety Awareness
There are
telltale signs that spring has arrived: flowers blooming;
fresh, crisp air; and more opportunities for outside
activities. However, there are also more harmful
ultraviolet (UV) sun rays that could increase chances of
developing skin cancer.
In fact, experts at The Weather Channel report that spring is the
time when the sun's rays are positioned to do the most
damage.
"Basically the sun gets higher in the sky during the day [in
spring] and the rays are more direct," explained Stu
Ostro, a senior meteorologist at The Weather Channel.
"Those rays are the same ones that also heat up the
atmosphere, causing spring and summer to be here."
With more of the sun's energy getting through, the threat to skin
increases.
While doctors can't point to one reason to explain why the number
of melanoma cases -- a highly fatal form of skin cancer --
has increased 150 percent since the 1970s, they do say
that education is key to sun protection. Experts say it's
a good idea to cover exposed skin and wear sun screen all
year long.
Ostro said there are several misconceptions about the damaging rays
from Earth's closest star.
"The potential for damaging sun rays to get to your skin has
nothing to do with temperature," he explained.
"It can be a cool day, but if it's sunny, those UV
rays will get through."
Experts also warn that you can get still sunburned on a cloudy
days. Doctors report that as much as 50 percent of harmful
rays can penetrate moderate cloud cover, or even be
reflected and cause sunburns in the shade.
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