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ENVIRONMENT:
Why Is the Ozone
Hole Growing?
Stephen
Leahy*
TORONTO, (Tierramérica) -
A huge ozone hole has developed
over Antarctica for the second
year running, exposing southern
Argentina and Chile to high
levels of damaging ultraviolet
radiation from the Sun.
The "hole" over the South Pole
-- actually an annual thinning
of the ozone layer during the
southern hemisphere spring
months of September and October
-- currently measures about 25
million square km and growing,
according to European Space
Agency satellite data, and it
may yet become the biggest hole
in history.
While this seems at odds with
recent announcements that the
amount of ozone-depleting
chlorofluorocarbons (CFCs) in
the lower atmosphere has finally
started to decline, those
chemicals will remain in the
atmosphere for many decades.
Meanwhile, increases in other
ozone-depleting substances like
methyl bromide are rising and
continued illegal use of CFCs
means the fight to protect the
ozone layer is far from over.
"New holes will likely develop
for at least the next 30 to 40
years," says Craig Long, a
meteorologist with the U.S.
National Oceanographic and
Atmospheric Administration's (NOAA)
Climate Prediction Centre,
located in the eastern state
Maryland.
"This year's Antarctic hole
should reach its maximum size
mid-September," Long told
Tierramérica. The timing
coincides with the United
Nation's International Day for
the Preservation of the Ozone
Layer, September 16.
"Thanks to the Montreal Protocol
on Substances that Deplete the
Ozone Layer, the risk of harmful
radiation appears to be
receding," said UN
Secretary-General Kofi Annan in
a statement.
The 1987 Montreal Protocol
requires the 184 nations that
signed it to phase out the use
of CFCs and nearly 100 other
chemicals that break down the
three-oxygen ozone molecules in
the Earth's stratosphere. The
ozone layer covers the entire
planet at an altitude of around
15 to 30 km and protects living
organisms from harmful
ultraviolet (UV) rays.
Reduced ozone levels over the
past few decades has increased
UV exposure around the world,
resulting in higher levels of
skin cancer, eye disease and
other health issues in humans
and in many other species of
animals and in plants.
But there was a levelling off of
declining ozone levels globally
between 1996 and 2002, according
to a new study by the Centre for
Integrating Statistical and
Environmental Science at the
University of Chicago.
While this is good news,
scientists urged caution. "Some
of these chemicals remain in the
stratosphere for many decades,
meaning that chemicals produced
years ago will continue to be
harmful for decades to come,"
said Sherwood Rowland, in a
statement.
Rowland and colleagues Mario
Molina and Paul Crutzen won the
1995 Nobel Prize in Chemistry
for their work identifying the
threat to the ozone layer in the
1970s.
But there is concern because the
Montreal Protocol allows the
release of other ozone depleting
substances for critical
short-term use.
For example, methyl bromide was
to have been completely phased
out by Jan. 1, 2005. However,
U.S. vegetable and fruit growers
will use nearly 10 million kg
(23 million pounds) of the
chemical pesticide in 2005 --
more than the country used in
2002.
The United States has convinced
countries party to the Protocol
to continue to allow some 8.5
million kg of methyl bromide in
2006, more than the rest of the
industrialised world combined.
Although there are alternatives,
methyl bromide is cheap and easy
to use.
Alternatives to CFCs, meanwhile,
are in wide use throughout the
world, but because they are more
expensive there is a thriving
black market trade for CFC use
as refrigerants, fire
suppressants and industrial
solvents.
Millions of pounds of CFCs have
been illegally imported into the
United States. Though the
problem may be on the decline
there, it is "an emerging
significant problem especially
in Asia" according to UN
Environment Program (UNEP). The
region still has equipment
reliant on CFCs, despite
commitments to reduce
consumption and production these
gases.
Under the Montreal Protocol,
developing countries agreed to
reduce CFC consumption 50
percent by January 2005, and to
fully eliminate use by January
2010.
This has led to increased
smuggling of these chemicals and
hampered adoption of
alternatives, UNEP reported in
January.
Finally, weather conditions can
also exacerbate ozone loss over
the polar regions. The Arctic
has had fewer and smaller ozone
holes than Antarctica but
suffered its greatest-ever loss
last winter due to extremely
cold conditions.
Some experts blame climate
change.
As the Earth surface warms, the
upper atmosphere is getting
colder in the polar regions,
creating just the right
conditions for chemicals like
CFCs and bromine to destroy
ozone.
Although more is known about
climate change impacts in the
Arctic, the same thing could
potentially happen in
Antarctica, Claus Zehner, of the
European Space Agency in Italy,
told Tierramérica.
Ultimately, local weather and
the degree to which the Montreal
Protocol is respected worldwide
will determine if there will be
ozone holes in the second half
of the 21st century, Zehner
said.
What's certain is that this
southern hemisphere spring,
residents of southern Chile and
Argentina, and possibly New
Zealand and Australia, will need
to protect themselves more than
ever from exposure to the Sun's
harmful rays.
(* Stephen Leahy is an IPS
correspondent. Originally
published Sep. 10 by Latin
American newspapers that are
part of the Tierramérica
network. Tierramérica is a
specialised news service
produced by IPS with the backing
of the United Nations
Development Programme and the
United Nations Environment
Programme.) |
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