Amid the anti-globalist chest-thumping of Brexit, Donald Trump, and the Brazilian president, Jair Bolsonaro, it may sound like the stuff of folklore. But there was a time in the recent past when all the countries of the world moved quickly to discuss a common threat, agreed an ambitious plan of action and made it work.

The Montreal protocol, which came into effect 30 years ago, was drawn up to address the alarming thinning of the ozone layer in the Earth’s stratosphere. It was the first agreement in the history of the United Nations to be ratified by all 197 countries. Since it came into effect on 1 January 1989, more than 99% of the gases responsible for the problem have been eradicated and the “ozone hole” – which, in the late 80s, vied for headline space with the cold war, Diana, Princess of Wales, and Madonna – is receding in the sky and the memory.

According to the latest UN study, the “ozone holes” (there are actually two: one above each pole) are healing at the rate of 1% to 3% a decade and will have completely vanished in the northern hemisphere by the 2030s and the southern hemisphere by the 2060s. This is cause for back-slapping, but also frustration that the world has not been able to unite as effectively over the climate and biodiversity crises. Here are half a dozen lessons.

Imagery and language matter



The satellite animation of the changing atmosphere over the Antarctic first shown in 1985 appeared to show a growing “ozone hole”. This was a scientifically imprecise description of the thinning that was concentrated at both poles, but the metaphor – of the roof over our home planet being punctured – captured the public imagination and, most importantly, conveyed a sense of urgency. By contrast, many people feel distant from climate problems, which are usually illustrated with images of polar bears, filled with caveats and headlined with vague labels, such as “global warming”, which sounds benign (or even desirable for those living in cold countries), and “climate change”, which comes across as a statement of the obvious.

Safety first



When scientists raised the alarm about chlorofluorocarbon (CFC) gases, there was initially uncertainty about their impact on the atmosphere and the process, but the risks from sunlight weakly filtered by the ozone layer (cancer, crop failure, ocean ecosystem collapse) were so great that world leaders decided not to wait. Instead, they applied the “precautionary principle”: “If in doubt, cut it out.” Even before the science was settled, they started to act. This was also supposed to be the case with the climate, but lobbying to deny the validity of the science, particularly in the US, has stymied action.

Speed counts



Governments temporarily put aside cold-war hostilities and united rapidly around a solution to the ozone problem. From the first research in 1973, it took just 16 years for the world to discuss, agree and put in place a solution that reversed the trend. By comparison, scientific warnings that carbon dioxide emissions could disrupt the climate date back to at least 1962 (and the risks were speculated on much earlier). Yet despite numerous international agreements on the subject since then (Rio 1992, Kyoto 1998, Copenhagen 2009, Paris 2015), emissions are still climbing.

Leaders should lead



In the 80s, the environment was not yet the polarising issue it has become, but the dominant figures – including the US president, George HW Bush, the Soviet leader, Mikhail Gorbachev, and the British prime minister, Margaret Thatcher – still had to overcome business interests, treasury doubts and political short-termism to protect the future health of the planet. They refused to accept the delaying tactics of chemical companies, some of which argued action should wait until the science was clearer. Today, Trump, Bolsonaro and the Russian president, Vladimir Putin, represent fossil fuel interests, deny science and undermine international cooperation.

The burden must be shared



The phased ban on CFCs and dozens of other ozone-depleting gases was an economic blow to chemical firms, refrigerator producers and aerosol-spray manufacturers. Rich countries dealt with the job losses, technology upgrades and other economic consequences internally, but also provided support for poorer nations to manage the transition. From 1991 to 2005, pledges totalled $3.1bn. Similar arrangements exist for climate accords, but the sums need to be far higher because the actions are so much more expensive, the responsibility of industrialised nations is so much greater, and the impact on poor countries is incalculably worse.

If it’s worth doing, it’s worth improving



The Montreal protocol has been updated numerous times as the science has sharpened and new climate goals have been incorporated. This month, the Kigali amendment added a plan to cut hydrofluorocarbons by more than 80% over the next 30 years, which would reduce global heating by 0.4C by the end of the century. Under the Paris climate agreement, governments are supposed to ratchet up the ambition of their pledges to cut emissions, but most governments are failing to meet even their current inadequate targets.

Looking at this list, a millennial might be tempted to conclude that the Montreal protocol was possible because it came about in a golden age when leaders were smarter, politicians more representative and populations more amenable to scientific persuasion. But, as anyone alive in 1989 knows, that is far too simple an explanation. The reality is that environmental action was easier then because the world had more ecological breathing room, capitalism was less dominant and the corporate push-back – and control over politics – was weaker. The ozone layer was a relatively simple fix compared with the climate, which is the biggest, most complex, multidimensional challenge humanity has ever faced. It is one thing confronting a handful of chemical firms, quite another to take on the world’s fossil fuel companies, car manufacturers, cement-makers and agribusiness conglomerates, representing hundreds of millions of jobs, trillions of dollars and 200-odd years of industrial development.

Bush, Thatcher, Gorbachev and the then Chinese leader, Deng Xiaoping, knew this in 1989, when global temperatures were already rising at an unnaturally rapid rate. A year earlier, in a US congressional testimony reported throughout the world, the then Nasa scientist Jim Hansen had declared “with 99% confidence” that this heating was a result of human activity. They also knew the problem would be easier to solve then than 30 years in the future. Initially, Bush promised to lead a determined global response to climate change, but – as the short-term costs of a long-term solution became apparent – he balked. Instead of a comprehensive response, he merely strengthened research, paved the way for a drawn-out global negotiating process and complacently put his faith in future innovation and entrepreneurship.

He may well have reassured himself that his environmental legacy was secure, thanks to action on ozone. But the climate can that he and others kicked forward 30 years ago is still clanking through the corridors of global conferences. It is a lot rustier now, but still basically the same half-response to a problem that becomes bigger and harder to solve with every year that passes.

So this year’s anniversary of the implementation of the Montreal protocol should not just inspire nostalgia for 1989, but a curse on the first generation of leaders to dodge climate responsibility. And as we are already suffering the consequences of their failure, it should remind us that every day of delay has a massive and imminent cost. Each fraction of a degree of global heating that can be prevented will save lives, species and money.

In our lifetimes, the ozone hole will be closed in the stratosphere while the increasingly angry beast of climate rages below. How angry is up to us. Montreal reminds us that nothing in politics is inevitable, that profits do not have to come before people, that global problems can have global solutions, that we can shape our own future. That depends on how far we are willing to push. In 1989, that wasn’t far enough. Nor has it been since. In 2003, the UN secretary-general, Kofi Annan, called the Montreal protocol “perhaps the single most successful international agreement to date”. Sadly, that still applies today.