The world agrees to stop: The Montreal Protocol is a treaty on the substances that deplete the ozone layer. It sets the rules for making, trading and using CFCs and other ODSs, and the dates to stop.
The points to remember
- An international treaty signed in 1987, in force in 1989, under the Vienna Convention (1985).
- It regulates the production, trade and use of CFCs and other ODSs.
- Countries must cut and then stop making and using ODSs by fixed dates.
- Trade controls: countries that signed may not buy ODSs from, or sell them to, countries that did not.
- Every UN country has ratified it (198 parties): the first treaty ever to reach that.
- It is called the most successful international environmental agreement yet.
Remember it as: Make, trade, use: the Protocol controls all three.
Real example: the ozone hole was reported in May 1985. Just over two years later, on 16 September 1987, 24 countries and the European Community signed the Protocol in Montreal, Canada. 16 September is now the International Day for the Preservation of the Ozone Layer.
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Not every country had to stop at once. Developing countries were given about ten years longer, and help from the Multilateral Fund.
The points to remember
- Developed countries stopped CFCs and halons by 1994-1996; developing countries by 2010.
- These staggered dates follow differentiated responsibility: rich countries caused most of the harm.
- Advantage: poorer countries get time to find money and technology, so more countries sign.
- Disadvantage: the global phase-out takes longer, and companies may move to countries with later dates.
- The Multilateral Fund pays developing countries to switch: over US$4 billion since 1991.
Staggered dates: for
- Time to raise money and get new technology
- More countries willing to sign
- Rich countries start at once
Staggered dates: against
- The world phase-out takes longer
- Companies may move to late countries
- Late countries may profit from trade
Real example: the United Kingdom and the United States had to stop making and using CFCs by 1996, while India, Brazil and Ghana had until 2010, with money from the Multilateral Fund to rebuild their factories.
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A treaty that keeps getting stronger: Each time the science improved, the parties added gases or brought dates forward. Replacing CFCs led first to HCFCs and then to HFCs, which the Kigali Amendment now controls.
The points to remember
- The treaty is strengthened as the science improves: London 1990, Copenhagen 1992 and others.
- CFCs were first replaced by HCFCs, then by HFCs, which do not destroy ozone at all.
- But HFCs are powerful greenhouse gases: HFC-134a warms about 1,430 times as much as CO2.
- The Kigali Amendment (Rwanda, 2016) cuts HFCs by 80-85% by the late 2040s.
- Why governments agreed: HFCs harm the climate, alternatives existed, and rich countries pay poorer ones.
- It could avoid 0.3-0.5 °C of warming by 2100: a climate co-benefit.
Real example: on 15 October 2016, in Kigali, Rwanda, the parties agreed to cut HFCs. Developed countries began in 2019; most developing countries froze their use in 2024 and will cut it by 80% by 2045.
Read the table: ODP shows harm to ozone; GWP shows harm to the climate. HFCs score 0 for ozone but high for warming.
Most environmental treaties fail to solve the problem they target. The Montreal Protocol worked, and the reasons explain when international cooperation can succeed.
The points to remember
- Clear science, widely accepted: scientists, the public and politicians understood what CFCs did.
- Alternatives were ready, so CFCs could be phased out smoothly.
- Few producers: a small number of chemical companies made most CFCs, so costs fell on few industries.
- Money: the Multilateral Fund paid for the switch in developing countries (technology transfer).
- Binding legal commitments, trade controls and monitoring; very few countries broke the rules.
- Flexible: tightened again and again as new science came in. ODS use fell by about 99%.
Science
- Molina and Rowland, 1974; the ozone hole, 1985.
- The public saw the risk: skin cancer.
Business
- A few big producers.
- Substitutes ready to sell.
Politics
- Binding dates and trade controls.
- Money for poorer countries.
Real example: in March 1988 DuPont, the world's largest maker of CFCs, announced that it would stop making them. Once the biggest producer had substitutes to sell, industry stopped fighting the ban.
Not just 'CFCs were banned': Say why it worked: alternatives, funding, binding rules, near-universal support, clear evidence.
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The Protocol is a success, but not a complete one. A strong answer weighs its limits too, and asks whether its lessons work for climate change.
The points to remember
- Slow recovery: CFCs last decades, so the Antarctic recovers only around 2066.
- Black market and illegal production: e.g. CFC-11 in eastern China until about 2018.
- Replacement gases have problems: HCFCs still destroy some ozone; HCFCs and HFCs are greenhouse gases.
- Not every ODS is covered: nitrous oxide and dichloromethane are not controlled.
- Hard to copy for climate: CO2 comes from every part of every economy, with no easy substitute.
- Yet it shows countries can cooperate: a model for other global problems.
Montreal Protocol (1987)
- A few gases, a few industries
- Cheap substitutes ready
- Every country signed
- ODS use down about 99%
Kyoto Protocol (1997)
- CO2 from the whole economy
- Few cheap substitutes then
- The US never ratified it
- Global emissions kept rising
Real example: the Kyoto Protocol set targets only for developed countries. The United States never ratified it, and Canada withdrew in 2011, so global carbon dioxide emissions kept rising.
A lesson for other problems: The Protocol shows that binding targets, money for poorer countries and ready alternatives can make global cooperation work.
How this comes up: Paper 2, Section A: why the Protocol is seen as successful [2], why HFCs were added [2], staggered dates [1] + [1]. Section B (c) [9]: discuss whether it is one of the most successful agreements.
Since 1987 the use of ozone-depleting substances has fallen by about 99%, yet the Antarctic ozone hole still forms every spring.
Discuss the claim that the Montreal Protocol is one of the most successful international agreements on a major environmental issue.
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