The Montreal Protocol on Substances That Deplete the Ozone Layer is an international treaty that has guided the gradual phaseout of production of chlorofluorocarbons (CFCs), halons, and other chemicals suspected of thinning the ozone layer. Restoration of the ozone layer is necessary to protect humans, animals, and plants from exposure to dangerous amounts of ultraviolet (UV) radiation. The Montreal Protocol was negotiated in 1987 and went into effect in January 1989. Revisions that have strengthened the Protocol have occurred regularly since 1990 as new scientific, environmental, and technical information has become available.
Each industrialized signatory nation agreed to reduce production of ozone-depleting substances (ODS) during the 1990s except for essential uses for which no substitutes could be found. Developing nations were given a longer timetable and financial assistance to phase out production. Each country created its own approach to achieving reductions. The United States relied on an accelerating tax on CFCs, while the European Union used regulations to restrict and then ban production, imports, and exports. By 2003, more than 90% of the production of certain ODS in industrialized countries was achieved, and more than 60% in developing countries.
The earth is protected from the sun’s UV radiation by stratospheric ozone that screens out about 99% of UV. ODS do not wash out in the lower levels of the atmosphere, but drift up to higher levels of the stratosphere and eventually break down from UV exposure and release chlorine atoms that in turn cause ozone (O3) to break down. The “hole” in the ozone layer over the Antarctic was documented in 1985, and other “holes” have subsequently been found over the Arctic, the Caribbean, and parts of Europe. Increased UV radiation is associated with greater incidences of skin cancer, cataracts, suppression of the immune system, and other health problems.
CFCs are the most widely known ODS to the general public for two reasons. First, CFCs were implicated as potential hazards in the mid-1970s, and their use in aerosol spray cans was banned in the United States in 1978. Second, CFCs were used in refrigeration systems, including air-conditioning in homes and vehicles, under brand names such as Freon, produced by DuPont Corporation. ODS are also used in foam insulation, industrial cleaning solvents, fire extinguishers, and some herbicides. Although ODS manufacturers opposed further restrictions in the early 1980s, by 1986 they reactivated research programs to find substitutes and supported the Montreal Protocol in 1987.
The United States began to regulate CFCs and other ODS in the 1990 revision to the Clean Air Act. The market incentive approach to environmental regulation was used to efficiently achieve the regulatory goal of eliminating ODS. Rather than taking a command-and-control approach by simply imposing a production ban by a certain date, the Environmental Protection Agency established an accelerating tax on CFC production. This escalating CFC tax sends clear price signals to consumers to look for alternatives and provides incentives to producers to create substitutes because the market for substitutes will become larger over time. At the same time, sales of CFCs were restricted to certified professionals who had to use prescribed equipment to capture and recycle the emissions.
An early deadline for phasing out CFC production in the United States was set for 2000, but it was subsequently moved to 1996 because of the speed with which substitute products were developed and marketed. Some early substitutes were known to have lower levels of ozone-depleting potential or contribute to global warming, but these are being replaced by the next generation of substitutes. Assistance to developing nations to meet the goals of the Montreal Protocol is provided by the Multilateral Fund for the Implementation of the Montreal Protocol. The fund received $2 billion from industrialized nations by 2003 to give grants for converting manufacturing processes, setting up national Ozone Offices, and supporting other tasks in developing nations. Two United Nations agencies and the World Bank administer the Fund.
The Montreal Protocol is widely viewed as a success in protecting the global commons. A few essential uses continue to require production of small quantities of ODS, for example, metered dose inhalers for asthma. However, estimates in 2003 indicate that the ozone layer will be restored between 2050 and 2065, depending on how quickly older ODS-using equipment is retired, and how quickly developing countries reduce ODS production and use. The Montreal Protocol was used as a model for the Kyoto Protocol, which deals with increasing amounts of greenhouse gases that are purported to be causing global warming. The Montreal Protocol has been much more successful in meeting its goals and deadlines because of the nature of the problem, the costs of achieving ODS reduction targets, and the number of actors that would be significantly affected. Ozone depletion was assessed by scientists more quickly and with more certainty about the relationship between ODS and the thinning ozone layer. The aggregate costs of meeting Montreal Protocol targets were much lower per capita than for the Kyoto targets. Finally, ozone-depleting substances were largely produced by a few large corporations in a few industrialized countries, so cooperation and monitoring were more easily