23 September 2002 00:00 [Source: ICB Americas]The earth's stratospheric ozone layer is recovering from the effect of chemical emissions, but it will remain vulnerable during the next decade, even if countries comply with international agreements to protect it, predicts a new scientific study.
The preliminary four year report was released last week by the United Nations Environment Program and the World Meteorological Organization on the fifteenth anniversary of the signing of the Montreal Protocol, an international agreement designed to protect the ozone layer, which shields the earth from the sun's ultraviolet rays.
"These results confirm that the Montreal Protocol is achieving its objectives. During the next decades, we should see a recovery of the ozone layer," says co-author Gerard Megie, who presented the report on behalf of 250 scientists from 37 countries.
But Mr. Megie, president of the France's National Scientific Research Center, also warns that the concentration of chlorine in the stratosphere "has now reached a maximum, and the ozone layer is still quite vulnerable. It is therefore extremely important that the control measures in the Montreal Protocol are strictly respected by all."
The report notes that the Antarctic "ozone hole" has increased in size over the past decade, but not as rapidly as during the 1980s. The scientists say, "it is not yet possible to say whether the area of the ozone hole has maximized."
They predict that, while another smaller ozone hole exists over the Arctic, "a future Arctic polar ozone hole similar to the Antarctic appears unlikely."
Developed countries responsible for most ozone depleting emissions have now phased out use of chlorofluorocarbons (CFCs) and related chemicals. To ensure these gains are not lost, the report states it is imperative that developing countries follow suit.
"While the majority of developing countries seemed to be on course in terms of compliance with their individual phase-out scheduled, some of them are still lagging behind," says Marco Gonzalez, executive secretary of the Ozone Secretariat.
Under the Montreal Protocol, developing countries are committed to reducing their consumption and production of CFCs by 50 percent by 2005 and by 85 percent by 2007.
By 2005, they must also reduce their consumption of halons by 50 percent, of methyl bromide by 20 percent, carbon tetrachloride by 85 percent and methylchloroform by 30 percent.
China and India are among the developing nations that have taken steps to eliminate the emission of ozone de-pleters, the report notes.
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