Montreal Protocol

The terms of the Montreal Protocol establish control measures, timelines, assessment and review, data reporting, methods of dealing with non-compliance, and measures to assist developing countries with compliance.

Timelines to phase out production and consumption of ozone-depleting substances (ODSs) covered by the Protocol are grouped by type. Specific ODS compounds belonging to each group are defined in the annexures to the Protocol.

Article 5 of the Protocol creates separate obligations for developing countries, allowing additional time to achieve compliance with the Protocol's control measures. Article 10 of the Protocol establishes a financial mechanism to help those countries achieve compliance.

The purpose of the Protocol is that each signatory states:

Recognizing that worldwide emissions of certain substances can significantly deplete and otherwise modify the ozone layer in a manner that is likely to result in adverse effects on human health and the environment. Determined to protect the ozone layer by taking precautionary measures to control equitably total global emissions of substances that deplete it with the ultimate objective of their elimination on the basis of developments in scientific knowledge

Acknowledging that special provision is required to meet the needs of developing countries

shall accept a series of stepped limits on CFC use and production, including:

For this group, production and consumption in non-Article 5 Parties was frozen (at a 1986 base level) on July 1, 1989, with 75% phasedown by 1994 and complete phase-out by 1996. For Article 5 Parties, consumption and production was frozen (at a base level of the average of 1995–97 amounts), followed by a 50% phasedown by 2005, an 85% phasedown by 2007, and 100% phase-out by 2010. Some chemicals were given individual attention (Carbon tetrachloride; 1,1,1-trichloroethane). The phasing-out of the less damaging HCFCs only began in 1996 and will go on until a complete phasing-out is achieved by 2030.

Production and consumption levels of Annex A - Group II Halons (halon-1211, -2404, and -1301) in non-Article 5 Parties was frozen (at a 1986 base level) on January 1, 1992, with complete phase-out by 1994. …

In 1974, the chemists Frank Sherwood Rowland and Mario Molina at the University of California, Irvine began studying the impacts of CFCs in the Earth's atmosphere. They discovered that CFC molecules were stable enough to remain in the atmosphere until they rose to the middle of the stratosphere, where they would be broken down by ultraviolet radiation and release a chlorine atom. Rowland and Molina then proposed that these chlorine atoms might be expected to cause the breakdown of large amounts of ozone (O3) in the stratosphere. In 1976, the U.S. National Academy of Sciences released a report that confirmed the scientific credibility of the ozone depletion hypothesis.

In 1982, representatives from 24 countries met in Stockholm, Sweden to decide on a "Global Framework Convention for the Protection of the Ozone Layer." The following year, a group of countries, including the United States, Canada, the Nordic Countries, and Switzerland, proposed a worldwide ban on "nonessential" uses of CFCs in spray cans.

In 1985, British Antarctic Survey scientists Joe Farman, Brian Gardiner and Jon Shanklin published results of abnormally low ozone concentrations above Halley Bay near the South Pole. They speculated that this was connected to increased levels of CFCs in the atmosphere. This unforeseen phenomenon in the Antarctic, as well as NASA's scientific images of the ozone hole played an important role in the Montreal Protocol negotiations. The impact of these studies, the metaphor 'ozone hole', and the colorful visual representation in a time lapse animation proved shocking enough for negotiators in Montreal, Canada to take the issue seriously.

Also in 1985, 20 nations, including most major CFC producers, signed the Vienna Convention, which established a framework for negotiating international regulations on ozone-depleting substances. From the discovery of the ozone hole, it only took 18 months to reach a binding agreement in Montreal, Canada. …

The main objective of the Multilateral Fund for the Implementation of the Montreal Protocol is to assist developing country parties to the Montreal Protocol whose annual per capita consumption and production of ozone depleting substances (ODS) is less than 0.3 kg to comply with the control measures of the Protocol. Currently, 147 of the 196 Parties to the Montreal Protocol meet these criteria (they are referred to as Article 5 countries).

It embodies the principle agreed at the United Nations Conference on Environment and Development in 1992 that countries have a common but differentiated responsibility to protect and manage the global commons.

The Fund is managed by an executive committee with an equal representation of seven industrialized and seven Article 5 countries, which are elected annually by a Meeting of the Parties. The Committee reports annually to the Meeting of the Parties on its operations. The work of the Multilateral Fund on the ground in developing countries is carried out by four Implementing Agencies, which have contractual agreements with the executive committee:

Up to 20 percent of the contributions of contributing parties can also be delivered through their bilateral agencies in the form of eligible projects and activities.

The fund is replenished on a three-year basis by the donors. Pledges amount to US$3.1 billion over the period 1991 to 2005. Funds are used, for example, to finance the conversion of existing manufacturing processes, train personnel, pay royalties and patent rights on new technologies, and establish national ozone offices.

As of October 2022, all Member States of the United Nations, the Cook Islands, Niue, the Holy See, the State of Palestine as well as the European Union have ratified the original Montreal Protocol, with the State of Palestine being the last party to ratify the agreement, bringing the total to 198. 197 of those parties (with the exception of the State of Palestine) have also ratified the London, Copenhagen, Montreal, and Beijing amendments.

Since the Montreal Protocol came into effect, the atmospheric concentrations of the most important chlorofluorocarbons and related chlorinated hydrocarbons have either leveled off or decreased. Halon concentrations have continued to increase, as the halons presently stored in fire extinguishers are released, but their rate of increase has slowed and their abundances are expected to begin to decline by about 2020. Also, the concentration of the HCFCs increased drastically at least partly because of many uses (e.g. used as solvents or refrigerating agents) CFCs were substituted with HCFCs. While there have been reports of attempts by individuals to circumvent the ban, e.g. by smuggling CFCs from undeveloped to developed nations, the overall level of compliance has been high. Statistical analysis from 2010 show a clear positive signal from the Montreal Protocol to the stratospheric ozone. In consequence, the Montreal Protocol has often been called the most successful international environmental agreement to date. In a 2001 report, NASA found the ozone thinning over Antarctica had remained the same thickness for the previous three years, however in 2003 the ozone hole grew to its second largest size. The 2006 scientific evaluation of the effects of the Montreal Protocol states, "The Montreal Protocol is working: There is clear evidence of a decrease in the atmospheric burden of ozone-depleting substances and some early signs of stratospheric ozone recovery." However, a more recent study seems to point to a relative increase in CFCs due to an unknown source.

The 2002 Scientific Assessment of Ozone Depletion predicted the ozone layer would return to 1980 levels by middle of the 21st century. In the 2022 assessment, this was delayed to 2066 for Antarctica, 2045 for the Arctic, and 2040 for most of the world. This is thought to be due to changes in calculation formulas as well as atmospheric changes.

Reported in 1997, significant production of CFCs occurred in Russia for sale on the black market to the EU throughout the 90s. Related US production and consumption was enabled by fraudulent reporting due to poor enforcement mechanisms. Similar illegal markets for CFCs were detected in Taiwan, Korea, and Hong Kong.

The Montreal Protocol is also expected to have effects on human health. A 2015 report by the U.S. …