U.N. Agreement Protects Ozone Layer Summary

  • Last updated on November 10, 2022

The members of the United Nations took an important step toward protecting the planet when they met to ratify an agreement to phase out substances known to be damaging to the stratosphere’s vitally important ozone layer.

Summary of Event

Earth’s ozone layer is located in the stratosphere between six and thirty-one miles above the planet’s surface. This layer is vitally important to life on Earth because it absorbs ultraviolet (UV) radiation from the Sun. In 1974, F. Sherwood Rowland and Mario J. Molina, scientists at the University of California, Irvine, published a paper warning of the dangers to the ozone layer of chlorofluorocarbons (CFCs) used in air-conditioning equipment, refrigerators, aerosol spray cans (such as those used for hair sprays and deodorants), industrial solvents, and a wide variety of other manufactured products. Ozone layer;Montreal Protocol Environmental policy, international United Nations;environmental policy [kw]U.N. Agreement Protects Ozone Layer (June 29, 1990) [kw]Agreement Protects Ozone Layer, U.N. (June 29, 1990) [kw]Ozone Layer, U.N. Agreement Protects (June 29, 1990) Montreal Protocol Ozone layer;Montreal Protocol Environmental policy, international United Nations;environmental policy [g]Europe;June 29, 1990: U.N. Agreement Protects Ozone Layer[07790] [g]United Kingdom;June 29, 1990: U.N. Agreement Protects Ozone Layer[07790] [g]England;June 29, 1990: U.N. Agreement Protects Ozone Layer[07790] [c]Environmental issues;June 29, 1990: U.N. Agreement Protects Ozone Layer[07790] [c]Diplomacy and international relations;June 29, 1990: U.N. Agreement Protects Ozone Layer[07790] [c]United Nations;June 29, 1990: U.N. Agreement Protects Ozone Layer[07790] Rowland, F. Sherwood Molina, Mario J. McMillan, Thomas Michael Reilly, William Reagan, Ronald [p]Reagan, Ronald;environmental policy Hodel, Donald

These CFCs were a primary cause of damage being done to the ozone layer. Chlorine atoms from CFCs take one oxygen atom away from the three oxygen atoms that make up an ozone molecule and form chlorine monoxide, which combines with another oxygen atom to form an oxygen molecule and a chlorine atom. The new oxygen molecules thus formed do not block the Sun’s UV light, so more of that light reaches Earth’s surface. The scientists found that this ozone destruction, caused by human technology, had been going on for years.

When too much UV light falls on the planet’s surface, serious damage results. Scientists do not yet understand all the potential harmful impacts of excessive UV light, but many ill effects have been established. It is known that UV light can cause cataracts to develop in the human eye, clouding the lens and resulting in blurred vision and eventual blindness. UV light can also cause skin damage, and increased incidence of skin cancers has been reported in many parts of the world where scientific observers have noted depletion of the ozone layer. UV rays are known to have harmful effects on the human immune system as well, making the body more susceptible to infectious diseases. In addition, UV radiation negatively affects the growth of photoplankton (one-celled animals) and krill (tiny shrimplike animals), which are at the bottom of the ocean food chain. Increased UV radiation is therefore a threat to all the life in the sea, directly or indirectly, and consequently a threat to the lives of human beings who depend on fish for food. UV rays also interfere with photosynthesis in plants and thus pose a potential threat to farm crop yields.

As scientists learned more about the depletion of Earth’s ozone layer, citizens of many countries were warned of the growing dangers of exposure to sunlight. They were cautioned to wear hats and protective clothing, to use a broad-spectrum sunscreen with a protection factor of at least 15, to stay out of the sun as much as possible between 10:00 a.m. and 3:00 p.m., and to wear sunglasses treated to absorb UV radiation. Such recommendations became standard throughout the world by the early twenty-first century.

In 1987, representatives of many nations met in Montreal, Quebec, to participate in sessions that produced the Montreal Protocol, which called for the phasing out of substances that harm the ozone layer (a protocol is a preliminary version of a proposed treaty that has yet to be ratified). Some governments were eager to ratify the protocol, but others balked because of the possible expenses and hardships to their nations if they followed the protocol’s recommendations, which included phasing out the use of CFCs and converting to harmless substitutes. India and China were two major countries that delayed ratifying the protocol because of the anticipated costs of switching to substitutes for CFCs. Representatives of twenty-four nations, mostly the developed, industrialized nations of the world, signed the agreement in Montreal on September 16, 1987.

The Third World countries that had initially balked at ratifying the protocol were eventually persuaded to do so by the creation of the Montreal Protocol Multilateral Fund. Given that the developed nations had created most of the ozone depletion problem with their heavy commercial use of destructive chemicals, many nations thought it appropriate that the developed nations bear the greatest cost of implementing the protocol’s requirements. On June 29, 1990, representatives of ninety-three nations met in London and agreed to ban production of most ozone-destroying chemicals by the end of the twentieth century.

In November, 1992, delegates from all over the world met in Copenhagen, Denmark, to discuss further revisions of the protocol because of alarming new discoveries about the damage being done to the ozone layer. It was agreed to phase out production of CFCs and carbon tetrachloride by January 1, 1996; to ban the production of halons by 1994; to ban production of methyl chloroform by 1996; to control the use of hydrochlorofluorocarbons (HCFSs) and eliminate them completely by 2030; and to increase the Montreal Protocol Multilateral Fund to make it possible for developing nations to accelerate the changeover from machinery and consumer products using ozone-destroying gases to harmless alternatives.


The Montreal Protocol was one of the most important and most successful examples of international cooperation since the formation of the United Nations. The historic agreement served to prove the contention of environmentalists that international peace and cooperation could be achieved through recognition by all the world’s people that they are mutually interdependent on the bounty of “Spaceship Earth,” a pinpoint of rotating matter that could conceivably be the only home of life in all the vastness of the cosmos. Ultraviolet radiation Chlorofluorocarbons Montreal Protocol

The publicity attending the various meetings on the Montreal Protocol made the entire world aware of the dangers posed by rampant technological development. Some libertarians and political conservatives argued that the danger of the ozone layer’s destruction had been grossly exaggerated and that special interests were using the issue as a scare tactic to promote world government, greater bureaucratic interference in private enterprise, and ultimately universal socialism. Such criticisms were voiced by a minority, however, and did little to impede the world’s cooperative efforts to halt ozone damage by banning the use of CFCs and other dangerous chemicals, a goal largely achieved by the end of the 1990’s. Thanks to the changes made because of the protocol, ozone depletion had leveled off by the early twenty-first century, leading some scientists to predict that if the trend continued and ozone-depleting substances were eliminated, the ozone layer would naturally regenerate itself by the middle of the twenty-first century.

The Montreal Protocol spurred technological innovation. Scientists, engineers, and manufacturers were motivated to find effective substitutes for CFCs, as there was obviously much money to be made. They also had to invent techniques to replace such potentially dangerous chemicals as those contained in refrigerator coolants without releasing the gases into the atmosphere. The technological responses to the ozone crisis illustrated economist Julian Simon’s thesis that, given a free market economy, people are capable of solving any problems they create. It is doubtful that commercial interests would have been motivated to invent substitutes for CFCs without government intervention.

The worldwide attention to the ozone depletion problem made consumers aware of their own important part in environmental damage and their responsibility for environmental protection. The result was a general consciousness-raising that proved beneficial in many ways. Teachers at all grade levels helped by making young people aware of the dangers of ozone destruction, including the dangers of too much exposure to sunlight. As a result of classroom instruction, many young people became more knowledgeable about environmental issues than most of their elders.

The Montreal Protocol proved that rich nations and poor nations—nations with different languages, cultures, religions, and economic interests—could come together to agree on one common program. The complex negotiations conducted over a period of many years provided valuable experience in resolving international problems affecting the global environment. The representatives of the rich and powerful nations learned that they had to understand the problems and aspirations of the world’s underprivileged majority, who were only beginning to enjoy the kinds of consumer products that were causing environmental damage.

In the long run, the concern over ozone depletion may prove a boon to humanity because of the lessons learned as governments with conflicting agendas were forced to work together expeditiously for the common good. William Reilly, the administrator of the U.S. Environmental Protection Agency who headed the U.S. delegation to the London conference, accurately described the Montreal Protocol as “a marvelous example of worldwide cooperation really without precedent.” Montreal Protocol Ozone layer;Montreal Protocol Environmental policy, international United Nations;environmental policy

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Benedick, Richard Elliot. Ozone Diplomacy: New Directions in Safeguarding the Planet. 2d rev. ed. Cambridge, Mass.: Harvard University Press, 1998. Presents a chronological discussion of the Montreal Protocol meetings and subsequent sessions by the chief U.S. negotiator. Makes technical issues understandable to nonspecialists. Discusses the complex problem of getting many different nations with conflicting interests to agree on a single program.
  • citation-type="booksimple"

    xlink:type="simple">Clark, Sarah L. Protecting the Ozone Layer: What You Can Do—A Citizen’s Guide to Reducing the Use of Ozone-Depleting Chemicals. New York: Environmental Information Exchange, Environmental Defense Fund, 1988. Brief volume offers specific guidelines and concrete examples with the aim of involving consumers in the fight to save the ozone layer from further devastation.
  • citation-type="booksimple"

    xlink:type="simple">Firor, John. The Changing Atmosphere: A Global Challenge. New Haven, Conn.: Yale University Press, 1990. Examines the complex interrelationships among acid rain, climate warming, and depletion of the ozone layer. Provides a good overview of these problems and their possible solutions, with emphasis on the gravity of the situation. Argues that population control is vital to solving the world’s atmospheric problems.
  • citation-type="booksimple"

    xlink:type="simple">Gliedman, John. “Is the Pact Too Little, Too Late?” The Nation, October 10, 1987, 376-380. Illustrated article, published shortly after the Montreal Protocol meetings, questions whether the international agreement is comprehensive enough to protect the ozone layer. Suggests that scientists do not have sufficient understanding of the problem.
  • citation-type="booksimple"

    xlink:type="simple">Gore, Al. Earth in the Balance: Ecology and the Human Spirit. 1992. Reprint. Emmaus, Pa.: Rodale Press, 2006. Highly readable book by an environmental crusader who became vice president of the United States in 1993. Presents an overview of the ecological crisis and offers pragmatic suggestions for bringing the earth back into ecological balance. Discusses the Montreal Protocol and the work of Rowland and Molina. Includes excellent bibliography.
  • citation-type="booksimple"

    xlink:type="simple">Gribbin, John R. The Hole in the Sky: Man’s Threat to the Ozone Layer. New York: Bantam Books, 1988. Discusses the ozone depletion problem, including a review of the major events and scientific principles, using nontechnical language. Summarizes proposed solutions to the problem.
  • citation-type="booksimple"

    xlink:type="simple">Klingeman, Henry. “The Twilight Ozone: D. Hodel’s Alleged Remarks Concerning the International Protocol on Ozone.” National Review, August 14, 1987, 40-41. Discusses Interior Secretary Hodel’s views on the Montreal Protocol at the time of the initial meetings. Indicates that many important people in government were unimpressed by the scientific data and were instead concerned primarily about the economic effects of banning CFCs.
  • citation-type="booksimple"

    xlink:type="simple">Lemonick, Michael D. “The Ozone Vanishes.” Time, February 17, 1992, 60-68. Illustrated cover story warns that the ozone layer is being depleted faster than anyone had previously anticipated and that holes would be opening up above Russia, Scandinavia, Germany, Britain, Canada, and northern New England. Discusses possible technological interventions to save the ozone layer and ways to reduce exposure to UV light.
  • citation-type="booksimple"

    xlink:type="simple">Molina, M. J., and F. S. Rowland. “Stratospheric Sink for Chlorofluoromethanes: Chlorine Atom-Catalyzed Destruction of Ozone.” Nature 249 (1974): 810-812. This technical discussion is of great historic importance because it alerted the world to the dangers of ozone depletion and led to the subsequent research, media publicity, consumer activism, political negotiations, and final international accord on the problem.
  • citation-type="booksimple"

    xlink:type="simple">Parson, Edward A. Protecting the Ozone Layer: Science and Strategy. New York: Oxford University Press, 2003. Presents a comprehensive history of international efforts to protect the ozone layer.

United Nations Holds an Environmental Conference in Stockholm

Rowland and Molina Theorize That Freon Causes Ozone Depletion

Chlorofluorocarbons Are Banned in the United States

Researchers Discover a Hole in the Ozone Layer

Our Common Future Is Published

United Nations Creates a Panel to Study Climate Change

“An Anti-Environmentalist Manifesto” Signals a Backlash

Earth Summit Convenes in Rio de Janeiro

Categories: History