Ozone layer could recover by 2040
The hole in the ozone layer in the southern hemisphere could be reach minimum levels by 2010 but may be fully recovered by 2040. Levels of ozone in the northern hemisphere may start to rise after 2010 and massive ozone depletion like that responsible for the vast Antarctic hole is unlikely to occur again in the predictable future.
This forecast come from new set of computer models from a group of scientists in Japan who have been the first to include complex chemical variations in greenhouse gas emissions and sea surface temperature in these global climate models. Previous, more simplistic models have made different predictions including that a huge hole in the Artic ozone layer could appear within the next 10 to 15 years, comparable to the Antarctic destruction during the late 1980s.
The present study concludes that presence of man-made chlorine in the southern high latitude stratosphere will contribute the most to future to ozone depletion.
International restrictions on emissions of ozone destroying chemicals such as CFCs (chlorofluorocarbons) are starting to take effect. A recent study from the United Nations Environment Program (UNEP) on the state of the globe environment over the past 30 years has highlighted that the consumption of halogen containing compounds has decreased by 85% since the late 1980s when the Montreal Protocol was signed.
Another study released this week has revealed that humans may be responsible for generating a quarter of the levels of carbonyl sulphate in the atmosphere, a compound linked with the production of aerosols and depletion of the ozone layer. Carbonyl sulphate is the most abundant sulphur-containing gas in the lower layers of the Earth’s atmosphere. The gas is formed naturally but is also produced by a chemical reaction of carbon disulphide in the atmosphere, a compound emitted from a variety of industrial processes.
Information on pre-industrial levels of atmospheric carbonyl sulphate has been collected from ice cores in West Antarctic. The team from the University of California at Irvine are the first to take such measurements from ice.
Both studies are published by the American Geophysical Union.
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