2003 Ozone Hole May Be Record Size, Australia Says
Fri August 22, 2003 02:57 AM ET
By Michael Perry
SYDNEY (Reuters) - The ozone hole over the Antarctic is growing at a rate that suggests it could be headed for a record size this year, Australian scientists said on Friday.
A study by Australian Antarctic bases attributed the development to colder temperatures in the stratosphere where the ozone hole forms.
"The growth at the moment is similar to 2000 when the hole was a record size," Australian Antarctic Division scientist Andrew Klekociuk told Reuters on Friday.
Ozone is a protective layer in the atmosphere that shields the Earth from the sun's rays, in particular ultraviolet-B radiation that can cause skin cancer, cataracts and can harm marine life. In 2000, NASA said the ozone hole expanded to a record 10.9 million square miles, three times the size of Australia or the United States, excluding Alaska.
"This is in contrast to the situation in 2002 when unusually warm conditions produced the smallest ozone hole since 1988," Klekociuk said.
The ozone hole in 2003 presently covers all of the Antarctic.
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Ozone hole is bigger than it has ever been
By Clive Cookson in Manchester
Published: September 12 2003 19:45 | Last Updated: September 12 2003 19:45
The Antarctic ozone hole is bigger than it has ever been at this time of year, threatening populated regions of south America and New Zealand with harmful levels of ultraviolet radiation.
Last year's hole was smaller than those recorded over the previous decade, leading to hopes that the protective ozone layer in the upper atmosphere was beginning to recover from its destruction by man-made CFC chemicals. But early observations reported on Friday to the British Association science festival at Salford University show that the hole, which appears every southern spring, is returning with a vengeance. The findings suggest that reduction of CFCs will take longer than expected to benefit the ozone layer.
Alan Rodger, who runs the British Antarctic Survey ozone-monitoring programme, said: "Last year's smaller hole should be regarded as exceptional and clearly a one-off event. It was... nothing to do with any reduction in ozone depleting chemicals."
The concentration of ozone destroying chemicals at the Earth's surface has fallen since 1994, following international agreement to phase out CFCs and related compounds through the Montreal Protocol. But levels in the stratosphere lag behind the surface by several years.
Dr Rodger said they are probably near their peak. "We predict that it will be a decade or more before we can say unambiguously that the ozone hole is recovering - assuming that the decline in ozone depleting chemicals continues," he said.
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Annan calls for even greater efforts to
protect world�s radiation-shielding ozone
16 September – With melanoma and other skin cancers killing 66,000 people each year, much of it due to the sun�s ultraviolet radiation, and children being especially vulnerable, United Nations Secretary-General Kofi Annan today called for even greater global effort to save the world�s radiation-shielding ozone layer.
�While we may be gratified with the progress that has been made through international cooperation, we must not be satisfied until the preservation of the ozone layer is assured,� Mr. Annan said in a message marking the International Day for the Preservation of the Ozone Layer. �Only then will we be able to say that we have saved our sky for future generations.�
He praised progress made under the Montreal Protocol on Substances that Deplete the Ozone Layer, ratified by 184 countries, as �impressive,� with scientists reporting a decline in depletion and the first signs of recovery following efforts to eliminate destructive man-made chemicals.
�However, we cannot be complacent,� he warned. �The ozone layer remains depleted above the Antarctic and the Arctic, as well as in the midlatitudes of both hemispheres of the earth.
�The same scientists warn that the ozone layer will remain particularly vulnerable during the next decade or so. As we look to the future, even greater political commitment and further action is required to ensure full compliance with the Montreal Protocol by developed and developing countries alike,� he said.
Several challenges remained to be met, Mr. Annan added. Developing countries must phase out the use of many ozone depleting substances within specified time schedules; illegal trade in chlorofluorocarbons must be curbed; alternatives to some current uses of methyl bromide must still be found; and more research is required on the relationship between depletion of the ozone layer and climate change.
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Press Release
SG/SM/8861
OBV/369
10/09/2003
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SECRETARY-GENERAL PRAISES IMPRESSIVE,
GLOBAL RESPONSE TO OZONE LAYER DESTRUCTION,
BUT WARNS �CANNOT BE COMPLACENT�, IN MESSAGE ON INTERNATIONAL DAY
Following is Secretary-General Kofi Annan�s message on the International
Day for the Preservation of the Ozone Layer, observed 16 September:
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The international community�s response to the destruction of the ozone layer, the shield that protects the earth from the sun�s deadly ultraviolet radiation, has been impressive. The Montreal Protocol on Substances that Deplete the Ozone Layer is working.
Recent findings by the world�s leading atmospheric scientists show that the level of chlorine in the upper atmosphere is at or near its peak. As a result, the rate of ozone layer depletion in the stratosphere has been observed to be declining. We are now seeing the first signs of the recovery of the ozone layer.
However, we cannot be complacent. The ozone layer remains depleted above the Antarctic and the Arctic, as well as in the midlatitudes of both hemispheres of the earth. The same scientists warn that the ozone layer will remain particularly vulnerable during the next decade or so. As we look to the future, even greater political commitment and further action is required to ensure full compliance with the Montreal Protocol by developed and developing countries alike.
There are several challenges to be met. For instance, all countries must ratify the Amendments to the Montreal Protocol. The developing country parties that entered their �compliance� period in 1999 must phase out the use of many ozone depleting substances within specified time schedules. The illegal trade in chlorofluorocarbons must be curbed. Parties to the Montreal Protocol need to meet the challenges involved in phasing out methyl bromide under the Copenhagen Amendment of 1992, as well as in evaluating and approving those critical uses allowed under the Montreal Protocol. Alternatives to some current uses of methyl bromide must still be found. And more research is required on the relationship between depletion of the ozone layer and climate change.
So, while we may be gratified with the progress that has been made through international cooperation, we must not be satisfied until the preservation of the ozone layer is assured. Only then will we be able to say that we have saved our sky for future generations.
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Dobson Unit
1 Dobson Unit (DU) is defined to be 0.01 mm thickness at STP (standard temperature and pressure). Ozone layer thickness is expressed in terms of Dobson units, which measure what its physical thickness would be if compressed in the Earth's atmosphere. In those terms, it's very thin indeed. A normal range is 300 to 500 Dobson units, which translates to an eighth of an inch-basically two stacked pennies. (Currently parts of the South Pole are reading 100 or less Dobson Units). In space, it's best not to envision the ozone layer as a distinct, measurable band. Instead, think of it in terms of parts per million concentrations in the stratosphere (the layer six to 30 miles above the Earth's surface).
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Total Ozone Mapping Spectrometer
Posted: 9/25/2003 9:32 PM Updated: 9/25/2003 9:33 PM
Antarctica ozone hole gets larger
By Dan Vergano, USA TODAY
The size of the ozone hole over Antarctica this year was the second-largest ever recorded, federal researchers reported Thursday. (Related item: Understanding ozone)
The region of ozone-depleted air peaked in size over the South Pole on Sept. 11, when it covered 10.9 million square miles, an area larger than North America. It measures second in size to the 2000 ozone hole that grew to 11.5 million square miles.
The size of the ozone hole has been carefully watched for decades. Atmospheric ozone screens harmful ultraviolet rays from the sun, but it's been eroded by chlorofluorocarbons and other man-made chemicals, leading to fears of increased skin cancers.
Thursday's report on the near-record size of the hole by researchers from NASA, the National Oceanic and Atmospheric Administration and the Naval Research Laboratory bolsters predictions that Earth faces sizable ozone holes for at least the next decade.
Current projections are for ozone holes to linger over Antarctica until at least 2050, says atmospheric scientist Paul Newman of NASA's Goddard Space Flight Center in Greenbelt, Md.
"Other things being equal in the Southern Hemisphere, we should not expect the ozone hole to disappear for 25 to 50 years, and we should sort of bottom out in terms of sizes in this decade," says Rolando Garcia of the National Center for Atmospheric Research in Boulder, Colo. "Of course, the atmosphere has ways of surprising us."
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26 September 2003
The latest ESA Earth Observation data show that reports of the demise of the ozone hole appearing annually above Antarctica have been greatly exaggerated.
The ozone hole is normally at its largest in September, but 2002 saw it at its smallest extent for more than a decade: 40% down on previous years. And a year ago yesterday ongoing satellite measurements of ozone - gathered by the Royal Dutch Meteorological Institute (KNMI) from the Global Ozone Monitoring Experiment (GOME) instrument on ESA�s ERS-2 satellite - showed it splitting in two.
�Using GOME we have gathered global stratospheric ozone data over the last eight years,� said Henk Eskes of KNMI. �And last year we were actually able to accurately predict the split a few days before it happened, as we were operating an ozone forecasting service.�
This dramatic reverse came just two years after the ozone hole had reached a record size – nearly 30 million sq km in 2000.
There was speculation that last year�s shrinking hole showed the ozone layer was recovering from damage caused by man-made chemicals including chlorofluorocarbons (CFCs) - in the past used in aerosol cans and refrigerators. But the bad news is that this year�s ozone hole looks much more like the 2000 than the 2002 version.
The latest ozone measurements acquired yesterday by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument aboard Envisat - ESA�s latest Earth Observation spacecraft – show this year�s ozone hole is in no danger of splitting this time, and, with an area of 26 million sq km, is almost as big as the 2000 ozone hole. The Belgian Institute for Space Aeronomy (BIRA-IASB) generated this value-adding MIPAS data based on level 2 products provided by ESA.
MIPAS is a German-built instrument that works by measuring infrared emissions from the Earth�s 'limb' – the band of atmosphere between planetary surface and empty space, as observed from behind Envisat. Working through day and night, MIPAS can map the atmospheric concentrations of more than 20 trace gases, including ozone as well as the pollutants that attack it. This makes the instrument invaluable in the study of atmospheric chemistry.
Stratospheric ozone absorbs up to 98% of the Sun�s harmful ultraviolet light. But human production of CFCs and other pollutants has led to thinning of this protective ozone layer. The discovery of this fact in the 1980s came as a shock.
�Nobody expected such an outcome,� said Eskes. �The very reason these classes of compounds were used by industry was because they were chemically inert – they did not react with other materials. Now we have learned to expect surprises, and we monitor accordingly.�
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European Space Agency (E.S.A.)
[Date: 2003-10-01]
New data provided by Envisat, the European Space Agency's Earth observation satellite, has revealed that the hole in the ozone layer over Antarctica is at a near record size, dashing hopes of a speedy recovery.
The ozone hole reached its record size of around 30 million square kilometres in 2000. However, measurements taken in 2002 revealed that it had shrunk by some 40 per cent in two years, and had even split in two, sparking theories that the ozone layer was rapidly repairing the damage caused by man made chemicals.
The latest data, generated by the Belgian institute for space aeronomy, shows that the two holes have again become one, currently covering an area of some 26 million square kilometres, and that the hole is unlikely to split in two.
For further information, please consult the following web address:
http://www.esa.int/export/esaCP/SEMH5K0P4HD_index_0.html
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