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Ozone hole: Now there are two
02/10/2002 10:16 - (SA)
Geneva - The ozone hole above the Antarctic has weakened and split into two smaller holes, an unprecedented phenomenon, says the World
Meteorological Organisation.
Experts said one of the two holes was west of the
southern tip of South America, and the other was centred southeast of the tip of Africa, according to an agency statement.
The two holes were relatively small, but each contained a core
depleted of more than 50% of its ozone.
Since then, the hole near Africa had kept its size and
intensity, but the hole near South America has weakened
considerably, said the Geneva-based organisation.
"Although the Antarctic ozone holes during 2000 and 2001 were
the largest so far, this year's ozone hole is not matching those
levels," said the statement.
Since the 1980s, a hole over Antarctica, considered as a
barometer of a major environmental problem, has started to develop every year in August or September, but starts to disappear in November or December - about two months later than this year.
The organisation's announcement confirms a prediction made last week by the Netherlands' Royal Meteorological Institute.
A natural phenomenon
The "hole" is, in fact, a thinning of the layer of ozone molecules in the stratosphere that filter out dangerous ultra-violet light from the sun.
This light is capable of damaging DNA, killing plant life
and causing skin cancer.
The layer is under attack from chemical-based compounds used as aerosol gases or refrigerants, although these substances are
gradually being phased out under a 1987 United Nations treaty, the Montreal Protocol.
The institute's researchers said they saw no connection between this year's weak ozone hole and a slow decrease in ozone-eating gases.
Instead, the explanation lay with the natural year-to-year
variability of atmospheric circulation that influenced the size and duration of the hole, they said. - Sapa-AFP
- SAPA
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