GENEVA ––
The hole in the ozone layer over the Antarctic is expected to
increase in size this year as early measurements show significant
ozone depletion, the United Nations weather agency said Tuesday.
Four observation
stations in the Antarctic this month reported a decrease in ozone
of between 20 and 35 percent compared with the period between
1964 and 1976, before the "ozone hole" was observed,
said Taysir al-Ghanem, spokesman for the World Meteorological
Organization.
"We cannot
be optimistic with these latest measurements," al-Ghanem
said. "We are expecting that the ozone hole this year is
going to be quite large, probably more than last year."
Ozone depletion
in the region starts in July and intensifies during August. WMO
says the biggest hole yet was recorded in 1998, when it reached
some 4.63 million square miles, partly helped by strong polar
winds.
Last year,
the hole reached 3.86 million square miles. The protective ozone
layer shields the earth from damaging ultraviolet rays.
Reduction
of the ozone layer can let rays from the sun reach the earth's
surface. Too much UV radiation can cause skin cancer and destroy
tiny plants at the beginning of the food chain.
One cause
of ozone depletion is chlorine and bromine released by manmade
chemical compounds such as chlorofluorocarbons, contained in some
aerosols.
WMO has said
those chemicals have leveled off thanks to the Montreal Protocol,
which commits countries to eliminating production and use of ozone-depleting
substances.
But the agency
says it could be 20 years before ozone levels recover noticeably.
Full recovery can be expected around 2050.
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