Stratospheric Ozone Depletion

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 fire-fighting 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. This book deals with implementation, policy issues and phase out of methyl bromide. In September 1987, 47 countries (including the United States) agreed to the Montreal Protocol on Substances that Deplete the Ozone Layer, which first required controls on the world''s consumption of ozone depleting substances. Over 160 countries have signed on to the Protocol, whose phasedown schedule for developed countries was accelerated twice and completely phased out Halon production at the end of 1994 and CFC production at the end of 1995. The Protocol''s coverage has also been extended to include hydrochlorofluorocarbons and other chlorine- and bromine-containing substances such as some solvents and methyl bromide, a widely used soil fumigant.