HTML _ IB89021 - Stratospheric Ozone Depletion: Regulatory issues
4-Nov-1996; David E. Gushee; 13 p.

Abstract: For two decades, scientists have been warning that chlorofluorocarbons (CFCs) and Halons (bromine-containing fluorocarbons) may deplete the stratospheric ozone shield that screens out some of the sun's harmful ultraviolet rays and thus regulates the amounts which reach the Earth's surface. CFCs have been used as refrigerants, solvents, foam blowing agents, and outside the United States as aerosol propellants; Halons are used primarily as firefighting agents. Increased radiation could result in an increase in skin cancers, suppression of the human immune system, and decreased productivity of terrestrial and aquatic organisms, including some commercially important crops. Recent evidence has strengthened the scientific case against CFCs and Halons and has revealed that ozone concentrations have begun to decline throughout the stratosphere, even in the Temperate Zones. Although much remains to be learned about the behavior of trace gases in the atmosphere, most scientists active in atmospheric research believe they have identified the key chemical species, their sources, and their modes of action. Some scientists remain unconvinced, but do not discount the possibility that the threat may be real. Scientists have also maintained that CFCs are also ¨greenhouse gases¨ and thus contributory to the possibility of global climate change. However, some very recent findings have cast doubt on this. In September 1987, 47 countries agreed to the Montreal Protocol on Substances that Deplete the Ozone Layer, which first froze world consumption of specified CFCs and Halons and by 2000 would reduce CFC consumption 50%. Currently, over 120 countries have signed on to the Protocol, whose phasedown schedule was accelerated twice and included a complete phaseout of Halons at the end of 1994 and of CFCs by the end of 1995. The Protocol's coverage has also been extended to include hydrochlorofluorocarbons (HCFCs) and other chlorine-and bromine-containing substances such as some solvents and methyl bromide, a widely used soil fumigant. About one-third of the demand for the primary ozone-depleting substances has been eliminated through conservation. Another third has been replaced by changes to ozone layer-friendly technologies. The remaining third, largely in air conditioning, refrigeration, and rigid foam blowing, is turning to substitute substances such as HCFCs (which have 1 to 10% of the ozone-depleting potential of CFCs and are thus also on a schedule to be phased out by 2030), HFCs (some of which have significant global warming potentials), and light hydrocarbons (which are flammable and tend to be less energy-efficient). At their latest meeting (Vienna, December 1995), the Parties agreed to phase down the use of HCFCs in developing countries and to phase out production of methyl bromide in developed countries by 2010, to cap its production in developing countries in 2002, and to revisit the role of methyl bromide in developing countries in 1997. Current remaining issues are basically associated with compliance by member countries, including a rising amount of smuggling of CFCs. [read report]

Topics: Stratospheric Ozone

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