As a chorus of questions rises about whether the world can act quickly enough to prevent climate breakdown, one lesson from recent history suggests rapid action is possible. The ozone layer, a blanket of gas that exists between 10 and 50 kilometres above the earth’s surface, is vital for protecting humankind from the sun’s powerful ultraviolet radiation. In 1974 a group of scientists published research suggesting that chemicals used in everyday products like aerosols, packaging and refrigerators could deplete the ozone layer – vastly increasing the incidence of skin cancer, cataracts and other harms to humans and wildlife on earth. In 1985, the ozone depletion theory was clearly proven, when a hole in the ozone layer was discovered over Antarctica.

The discovery of the hole was evidence that the magnitude of the problem was far greater than scientists had originally predicted. International alarm at the ozone layer’s thinning led to unprecedented multilateral action to ban the dangerous chemicals that were responsible for its deterioration – chlorofluorocarbons (CFCs). By 1987, just two years after the hole was discovered, an international treaty was in place that cut the use of CFCs in half. Three years later in 1990, the Montreal Protocol was strengthened to ban the use of CFCs altogether in industrialised countries by the year 2000 and by the year 2010 in developing countries.  Today, the use of CFCs is outlawed by 197 countries around the world and scientists concur that the ozone layer is slowly recovering as a result. Overall, the success in addressing the ozone problem can give us hope that global environmental problems can and have been solved by humanity’s timely collective action.

Wider relevance

The success in negotiating, strengthening and enforcing the Montreal Protocol should give hope to embattled climate change negotiators around the world – as it is evidence that multilateral initiatives can be effective in tackling the global environmental challenges we face. Although individual nation states fought for their own national interests throughout the Montreal negotiations, they did ultimately act in the interest of the global commons – and institute an outright ban on the use of  CFCs. The Montreal Protocol not only binds its signatories to prohibit the use of CFCs in their jurisdictions, it also introduced sanctions that prohibited trade in certain chemicals with non-signatories, creating a significant incentive for countries to sign up. What is striking as well is the effectiveness of the implementation of Montreal Protocol. It is the only global treaty to achieve universal ratification of 197 countries, and has achieved a compliance rate of 98%. As such, Montreal is evidence of the effectiveness of outright bans. Since Montreal, such bans have been harder for governments to contemplate, but the effectiveness of the Protocol shows that governments can and have used their powers to drive rapid transitions away from harmful substances and for the benefit of the environment.

Also interesting and relevant to the challenges of the climate movement today was the success of citizen-led campaigning on the relatively abstract and remote environmental problem of ozone depletion. Behind the success of the multilateral negotiations was well organized civil society campaigning – both in the US and around the world. Environmental organisations coalesced around the issue of CFCs – and through inventive public campaigns managed to spur changes in consumer behaviour, including widespread boycotts of products and companies that used CFCs. Consumer pressure forced action by some US-based companies even before the government introduced bans on the use of CFCs. By the time the ban was in place, the market for CFCs had dwindled, making their phase out more feasible.

Civil society action around CFCs extended beyond campaigning into directly driving industrial innovations. In 1992 when chemical companies attacked Greenpeace and their anti-CFC campaign for “criticizing and offering no solutions”, Greenpeace brought together a group of engineers to develop a prototype of a refrigerator that did not use CFCs. Within a few months, the engineers had developed a prototype for the “GreenFreeze” fridge – which used a mix of natural hydrocarbons instead of CFCs and so did not harm the ozone layer. Greenpeace subsequently founded a company to design and market GreenFreeze fridges, which ultimately revolutionised the domestic refrigeration sector – with more than a billion in use today.

The role of key industry players in the phase out of CFCs also provides lessons for how business interests can be harnessed to pursue environmental goals. Initially the producers of CFCs were hostile to any regulation, but by the time the Montreal protocol was being considered, the market had changed and the possibilities of profiting from the production of CFC substitutes had greatly increased – favouring some of the larger producers that had begun to research alternatives. This diversity within industry was harnessed and an alliance formed between the environmental movement and those companies that ultimately stood to gain from the increased regulations. Following initial resistance, DuPont, the main industry player responsible for a quarter of global CFC production, backed the initial draft of the Montreal Protocol and its subsequent strengthening, in part because it could benefit from exporting alternatives to CFCs to the European market as a domestic ban on the nonessential use of CFCs as aerosol propellants had been introduced in the US in 1978, spurring innovation.

Context and background

Chlorofluorocarbons (CFCs) are chemicals that were developed in the 1930s which, before they were banned, were used in a wide array of commercial and industrial processes. The household product that is most commonly associated with CFCs and the depletion of the ozone layer was aerosol sprays – such as deodorants or hair spray. But CFCs had many other uses including as a refrigerant – they were commonly used in fridges and air conditioners – as well as in Styrofoam packaging, solvents and fire extinguishers. As they are neither toxic nor flammable and relatively inexpensive to produce, CFCs were originally considered to be a miracle find for industry. By the 1970s there were produced and widely used by companies in the United States and Europe, and were increasingly employed by the industry of emerging economies such as China, Brazil and India.

In 1974 a group of scientists published their ozone depletion theory – which held that CFC chemicals once airborne travelled to the stratosphere where they were broken down by the sun’s ultraviolet radiation. These atoms then bonded with ozone molecules – which led to the depletion of this protective gas layer. This theory was confirmed when, in 1985, scientists identified an annual thinning of the ozone layer over Antarctica every spring. The thinning of the ozone layer over Antarctica has had particularly dire impacts for Australia and New Zealand, which given their proximity to the ozone layer, suffer the highest rates of skin cancer in the world.

Enabling factors

Key to the rapid transition to phase out CFCs was the widespread acceptance amongst the general public, business actors and world leaders of the severity and urgency of the problem; a consensus that was forged following the discovery of the ozone layer in 1985. However, the negotiations around the Montreal Protocol still had to handle the conflicting national interests of participating governments to reach a deal. The United States, a leader in the negotiations, was to a large extent influenced in its position by its business interests, which opposed any ban until 1986 when the company with the largest role in CFC production worldwide, DuPont, had developed successfully developed alternative chemicals. From this point forward, the US took the lead in pushing for a ban. European countries initially resisted this call until their own companies such as ICI had developed CFC substitutes, at which point they also agreed to the need for a ban. Developing countries were responsible for a comparatively small amount of CFC use, as 80% of CFCs were consumed in industrialized nations. However, emerging economies also resisted calls for a ban until an agreement was reached on financial assistance fund for technology transfer to the tune of $160 million.

An important factor that positively influenced the negotiations was the strength of the environmental movement in the US, and its ability to harness a global network on the issue of CFCs. In the 1970s, when scientists first published their ozone depletion theory, the US environmental movement had been growing in strength and organisation. The ozone layer campaign became the first major unifying campaign of organisations like Friends of the Earth and Sierra Club. These groups led awareness raising actions that targeted the public and encouraged boycotts of everyday products that used CFCs such as aerosols. Friends of the Earth-USA launched a “Styro-Wars” campaign, a “Stratospheric Defense Initiative” aimed at eliminating CFCs from polystyrene food packaging and other consumer products. After a flood of letters from school children, McDonalds eventually committed to cut CFCs from its packaging in 1987. The ozone layer campaign allowed for the consolidation of a global movement of civil society actors around a common cause. US-based NGOs shared their inventive campaigning approaches and tactics, which saw similar campaigns – putting pressure on both governments and local businesses – being launched by civil society in countries around the world.

The central role of business interests in driving the phase out CFCs must be highlighted. The cohesion of companies around the issue of CFCs can be explained by a few factors. First of all, the limited number of actors involved made it relatively easy to reach an agreement. Eighteen chemical companies accounted for most of the world’s production of CFCs in the early 1980s – mostly concentrated in the US, UK, France and Japan. DuPont was by far and away the most important player, producing around one quarter of the global output. This meant that once DuPont acted as the industry leader in the global negotiations, and once the company’s agreement for a ban was secured, the rest of the industry followed suit. Also important was the fact that, although the CFC market was important, it was not truly ‘big business’ – CFCs accounted for 3% of DuPont’s total sales.

The final, and perhaps most crucial factor, in the speed of the phase out of CFCs following the discovery of the ozone layer was the technological innovations to develop alternative chemicals. Once the science and the gravity of the situation became clear, DuPont began investing heavily in research into substitutes. By 1986, DuPont had successfully developed alternative chemicals that did not harm the ozone layer, at which point it became in their interest to support international ban on CFCs. The US position to support a ban followed in line with DuPont, at which point that the path to Montreal was cleared.

The story does not end there though. There is a postscript to this global collaboration that is proving thorny but positive. The year 2016 saw a meeting in Kigali, Rwanda, to agree a phasedown of another set of gases, which had originally been intended as a quick fix for CFCs, called hydrofluorocarbons (HFCs). While HFCs are safe for the ozone layer, they are a powerful greenhouse gas, a thousand times more potent than CO2 and a major contributor to climate change. In 2016, after nearly ten years of negotiations, more than 150 countries agreed to reduce their use of HFCs by 85 percent in the coming decades. However, the use of HFCs for air conditioning and refrigeration is growing at a fast pace in developing countries, in part because climate change is producing more and longer deadly heat waves and driving up summer temperatures. The Kigali Amendment to the Protocol, which was agreed in 2016 and came into effect from January 2019, is expected to prevent up to 80 billion tonnes CO2 equivalent of emissions by 2050, which will make a significant contribution to the Paris Agreement objective to limit the global temperature rise to well below 2°C, according to the UNEP.

The final deal divided the world economies into three groups, each with a target phasedown date. The richest countries, including the United States and those in the European Union, will reduce the production and consumption of HFCs from 2019. Much of the rest of the world, including China, Brazil and all of Africa, will freeze the use of HFCs by 2024. A small group of the world’s hottest countries such as Bahrain, India, Iran, Iraq, Kuwait, Oman, Pakistan, Qatar, Saudi Arabia, and the United Arab Emirates have the most lenient schedule and will freeze HFCs use by 2028.

The multilateral fund that allows this process to work by compensating poorer countries and paying for transfers of newer technology to them is highly dependent on US support. To date, the US had not ratified the agreement. This kind of multilateral fund is important in levelling the playing field and could also be replicated in other areas where lack of access to new technology might slow down shifts towards a low carbon economy.

Scope and evidence

  • It took only 2 years from the discovery of the ozone layer in 1985 for governments to agree to a global ban on the use of CFCsand a further 2 years for it to come into effect.
  • The Montreal Protocol is the only treaty ever to achieve universal ratification; with 197 countries enforcing the ban on CFCs.
  • Parties to the Montreal Protocol have achieved a compliance rate of over 98% of their treaty commitments, and many achieved their targets well ahead of the schedule outlined in the treaty.
  • Global observations have confirmed that atmospheric levels of key ozone depleting substances are going down and it is expected that by the middle of this century they will return to pre-1980 levels.
  • The United States estimates that by the year 2065 more than 6.3 million skin cancer deaths will have been avoided, an estimated US$4.2 trillion in healthcare costs will have been saved, and 22 million Americans born between 1985 and 2100 would avoid suffering from cataracts due to the implementation of the Montreal Protocol.
  • As most ozone depleting chemicals are also greenhouse gases, the Montreal Protocol has averted greenhouse gas emissions equivalent to more than 135 billion tonnes of CO2, making the Montreal Protocol an important contributor to the fight against global warming.



1970s, 1980s, 1990s

Areas of change

Clean energy