Montreal Protocol

THE MONTREAL PROTOcOL is an international treaty designed to protect the ozone layer by phasing out the production of a number substance (such as CFCs— Chlorofluoro compounds) believed to be responsible for ozone depletion. In the late 1920s, chemicals called chloroflourocarbons (cloro-floro-carbons) or CFCs, were invented. These chemicals were not poisonous and did not harm fabrics, plants, or people. Companies thought they were great products and used them in refrigerators, air conditioners, styrofoam packaging, and spray cans. From the 1920s to the 1970s, billions of CFC molecules were released into the air.

In the 1970s, scientists began to wonder what happened to all the CFCs after they had been in the air for a while. Scientists eventually learned that CFCs could float past the troposphere (troposphere is a layer of atmosphere that is closest to the Earth. It extends to about 3.7-10.5 mi. (6-17 km.) above the Earth's surface and is thickest at the equator. Temperatures in the troposphere decrease as altitude increases. They are warmer nearest the Earth, in part because gases in the troposphere are warmed by heat radiated from the earth.) up into the stratosphere (stratosphere is the second layer of atmosphere, and extends out beyond the troposphere, to about 31 mi. (50 km.) above the earth. Gases in the stratosphere are heated mainly by incoming radiation from the Sun; temperature in the stratosphere gradually increases as altitude increases. As a consequence of temperature differences between the troposphere and stratosphere, and the resulting circulation patterns, exchange of air between the two layers is slow. The stratosphere is also known as the ozone layer. The distribution of ozone is closely linked to the vertical structure of the atmosphere. Approximately 90 percent of all ozone molecules are found in a broad band within the stratosphere. This layer of ozone-rich air acts as an invisible filter to protect all life forms from over-exposure to the Sun's harmful ultraviolet (UV) rays. Long-term ozone depletion is result of human-activity.) where UV rays would break them down. The chemicals that make up CFCs, mainly chlorine and fluorine, float around the stratosphere, breaking up ozone molecules.

Although CFCs were invented in 1920s, and research in the impact of CFCs on the ozone layer began as early as the 1930s, it received attention mainly in 1970s. During the 1970s, concerns arose that stratospheric transport aircraft might damage the ozone layer. This concern started in 1973, when the American Chemists (Frank Sherwood and Mario Molina) decide to study the impact of CFCs on the Earth's atmosphere. They discovered that CFC molecules were stable enough to remain in the atmosphere until they got into the stratosphere where they would finally be broken down by ultraviolet radiation releasing a chlorine atom, after an average of 50-100 years for the two common CFCs.

In 1974, Sherwood Rowland and Mario Molina discovered a dramatic change in the chemical composition of our atmosphere, an enormous increase in concentration of chlorine throughout the world. This increase in chlorine is attributed to widespread use of CFCs. It was at this time that the theory was proposed that CFCs were depleting the ozone layer. At the time, CFCs were used in refrigeration, aerosol cans, and some industrial processes. Initially greeted with a great deal of skepticism, further research and monitoring began to convince the scientific community that the CFC hypothesis might be valid. In the late 1970s and early 1980s, some national governments imposed bans on CFCs as aerosol and other propel-lants in non-essential uses for antiperspirants, hair-sprays, and deodorants. In 1977, the United Nations Environment Program (UNEP) established the Coordinating Committee on the Ozone Layer.

In 1981, UNEP acted on a proposal submitted by a meeting of legal experts and decided to develop a global convention. In 1985, the Vienna Convention on the Protection of the Ozone Layer was signed. The period between the Vienna Convention (March 1985), and the Montreal Protocol (September 1987), was characterized by incredible progress in negotiations. In 1987 a hole in the ozone layer was found over Antarctica, the size of the United States. This discovery transformed politics and international negotiations. In 1987, over 60 countries met in Montreal (more than half of them were developing countries) to discuss the treaty. The global scientific community reached consensus, while meetings were held in Rome to clarify and quantify the current global emissions of ozone-depleting substances and future trends, and new mechanisms for control were discussed. By September 1987, the disagreements and lack of understanding on CFCs and its role on ozone depletion had given way to trust. In turn, the trust offered the prospect of consensus on control measures. Thus, on September 16, 1987, the Montreal Protocol on Substances that Deplete the Ozone Layer was signed by 24 countries. The treaty was opened for signature on September 16, 1987, and took effect on January 1, 1989. It has undergone five different revisions since: in 1990 (London), 1992 (Copenhagen), 1995 (Vienna), 1997 (Montreal), and 1999 (Beijing).

All Parties agreed to meet near-term targets of freezing consumption of key CFCs and halons at 1986 levels, and reducing consumption by 50 percent within next 10 years. While the Protocol is complex, its most important feature was the dynamic process for controlling ozone-depleting substances, in addition to those initially identified in the Protocol. One of the major steps was the amendment to the Montreal Protocol in Copenhagen, in 1992, which resulted in a further acceleration of the phase-out of several

The status of ratification as of October 10, 2007.

Ratification of:

Vienna Convention

Montreal Protocol

London Amendment

Copenhagen Amendment

Montreal Amendment

Beijing Amendment

Total number of countries







ozone-depleting substances. In addition to CFCs, hydrochlorofluorocarbons, and methyl bromide were added to the list of substances subject to control.

The Montreal Protocol was the first treaty to protect the atmosphere from human impacts on the ozone layer. The agreement and the way it was developed are unique. For instance, research findings were a vital part of the decision-making process, and scientific assessments are stipulated in the Protocol every four years as a basis for further decisions on ozone-depleting substances.

In 1979, many countries, including the United States, banned CFCs from manufacture or use. This was a big step toward fixing the problem. Today, no spray cans contain CFCs. Other chemicals are gradually replacing the CFCs in air conditioners. Scientists originally predicted that the ozone layer would be the thinnest around 2008, but then start recovering. But new research shows that other air pollution problems are not only worsening the general situation, but also slowing down the ozone layer's ability to rebound. There are products that still contain CFCs and need to be treated with care. One example of this is car air-conditioners. When the air-conditioner breaks, or the car is taken to a junkyard, the CFCs need to be carefully taken out and recycled or stored so that they do not leak into the air. This can be best achieved by educating people that they should have their car air conditioners fixed by mechanics who are certified to work with CFCs; it is essential in protecting human health (skin and eyes) from the harmful effects of UV rays.

The Montreal Protocol has been a success story and it owes a great deal of this success to the actions of the U.S. government, which played a very aggressive role in producing the protocol. American companies also played a large role in the protocol's success, because they stood at the forefront of technological innovation in creating substitutes for the chemicals that were causing ozone-depletion. All of these countries are complying with their obligations for it has been shown that the ozone-depleting chemicals' global emissions have decreased by over 95 percent since the Protocol was put into action. Atmospheric concentrations of all of these chemicals have also been declining since 1994. By 2050, it is expected that the ozone layer will return to its natural level. Since the Montreal Protocol, 15 of the worst CFCs were phased-out worldwide, with the United States, Europe, and Canada completely phasing-out all use of CFCs. As a result of all of these restrictions, new damage to the ozone layer has greatly decreased and the hole in shrinking.

Due to widespread adaptation and implementation, the Montreal Protocol is hailed as an example of exceptional international cooperation, which prompted Kofi Annan, the former Secretary General of the United Nations, to state that the Protocol is "Perhaps the single most successful international agreement to date "

sEE also: Carbon Dioxide; Mesosphere; Stratosphere; Technology; Thermosphere; Weather.

BIBLIOGRAPHY. L. Kelly, "Multilateral Fund for the Implementation of the Montreal Protocol," World Bank Operations Evaluation Department, (cited March 2007); C. Sunstein, "Montreal versus Kyoto: A Tale of Two Protocols," (The Harvard Environmental Law Review: v31/1, 2007); Technology and Economic Assessment Panel, December 1991, "Montreal Protocol On Substances That Deplete the Ozone Layer," (cited March 2007); United Nations Environment Programme, "Evolution of the Montreal Protocol," http://ozone.unep. org/Ratification_status/index.shtml (cited January 2008); Wisconsin Department of Natural Resources, "What is Ozone?" (cited January 2008).

Velma I. Grover Natural Resource Consultant

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