Over the next few years, ozone loss is projected to go from to worse
GLOBAL levels ofozone, which shields the
from the Sun's harmful ultraviolet
radiations, have fallen to a record
over the past 2 years. But the worst
R to come, according to the report of
an international scientific panel.
However, a redeeming feature of the
1994 Assessment Panel report, mandated under the 1987 Montreal Protocol on
Substances that Deplete the Ozone
Layer, is that the emissions of chemicals
harmful to ozone have also gone down.
The 'panel was set up under the auspices, of the Geneva-based World
Meteorological Organization (WMO)
and the United Nations Environment
Programme (UNEP) in Nairobi. It comprised 226 atmospheric science experts,
drawn from 29 countries.
The report reveals that the
atmospheric growth rates of
human-made compounds that
deplete the ozone layer, such as
chlorofluorocarbons (CFCs),
used in refrigeration, and
halons, used in fire extinguish
ers, have slowed in recent years
following reductions in global
emissions of these compounds.
Says UNEP executive director
Elizabeth Dowdeswell, "While
the 1994 Assessment Panel
report confirms that we are
heading in the right direc
tion, we cannot afford to be
complacent. The line that
divides complacency from cata
strophe is very thin and now is
not the time to break that
momentum."
The report lists 4 steps that will
steepen the fall from the peak halocarbon levels in the early decades of the
next century. reductions in emissions of
methyl bromide used as a soil and crop
fumigant, reductions in emissions of
hydrochlorofluorocarbons, the complete recapture (as opposed to recycling) Of CFcs, and halons banked in existing equipment.
The panel report contends that this
record depletion probably owed, at least
in part, to chemical processes linked to
the 1991 eruption of
Mount Pinatubo in the
Philippines.
Scientists reckon that
peak global ozone depletions would occur around
1998, mainly because of
the past emissions. Thereafter, the levels of ozonedepleting chlorine and
bromine are expected to
slowly decrease and the
ozone layer is expected to
recover in about 50 years.
Nelson I Sabogal, an
officer at, UNEWS Ozone
Secretarias
Nairobi, says that extrap
olation of
the rent trends 'suggests that
ozone loss relative to the late '60s
about 13 per cent at northern mid
tudes in winter and spring - abow
per cent above the current de
levels. And it is estimated that im
southern latitudes the ozone loss
11 per cent of the level in the late '60s.
According to UNEP, large inc
uv radiation on the earth's surface
been observej in the Antarctic and
southern part of South America
spring and winter, when the ozone
is observed. Further, elevated Liat the mid to high latitudes
observed in the northern hemi
1992 and 1993, corresponding
low ozone levels in those yeam
increase in ov radiation, experts
could lead to an increase in skin
cases and cataracts, especialiv
people residing in the mid-latitudes.
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