Image copyright AFP/Getty Images Image caption Now we can’t see ozone holes, but that’s just one of its lessons
It’s hard to deny that the protection of the ozone layer required a human presence way larger than the seven billion people now on Earth.
But what if that protection stopped existing?
So far, there have been seven successive agreements – six through the UN and one independent treaty – to protect the ozone layer.
There have also been more than 150 meetings of the Parties to the Montreal Protocol, the precursor treaty to the current agreement.
Nevertheless, the problem of loss of ozone remained.
No meaningful ozone protection has been introduced since 1987.
Now, though, the Arctic Ozone hole, which is capable of blocking out ultraviolet radiation – the key to skin cancer, including blindness – has not formed for eight consecutive years.
What are these lessons from the ozone layer case?
The Montreal Protocol came into force on 1 September 1987, a few months after an issue paper from the BBC brought global attention to the dangers of chlorofluorocarbons.
It committed hundreds of nations to reducing the production and use of these substances.
CFCs were chemicals, chemically similar to those used in cold showers but so potent that they were found to act as strong greenhouse gases and contribute to climate change.
The 1987 treaty was the work of the environment ministers of 30 countries, including the UK, the US, France, and Russia, and entered into force despite opposition from countries including the US, which had opposed a similar pact covering ozone protection.
By 1989, the total amount of CFCs used had been reduced more than 90%.
Work on CFCs came about in part because of work done for other countries by multinational corporations.
Nets made from CFCs by Honeywell were used to measure the size of the hole in the ozone layer, which is normally associated with years of clear summer days.
After the hole closed, Honeywell contacted the US Environmental Protection Agency and later the United Nations, seeking information about the steps it was taking to protect the ozone layer.
By then, CFCs were phased out of use by the US under the Montreal Protocol.
Big business still has a significant role to play in the protection of air quality – helping to decide how much industry grows in developing countries, by looking at their climate risks
But other businesses were also involved.
For example, a European firm, Britvic, got fluoridated water to be used in Europe because of worries about the acidity of chlorofluorocarbons.
The US and others were very interested in having CFCs as a component of biofuels.
But CFCs can also be used as catalysts for making plastics and coatings – helping to reduce emissions.
Big business still has a significant role to play in the protection of air quality – helping to decide how much industry grows in developing countries, by looking at their climate risks.
The original agreement involved helping developing countries to grow economically while protecting their environment.
The first steps in taking to protect ozone came after the 1987 Montreal Protocol, but the main emphasis since then has been on developing countries for helping to continue the protection of ozone.
The former Polish Prime Minister Robert Gros Poland led the debate around a second key element of the Montreal Protocol – the 1996 agreement to give developing countries the money they needed to tackle the problem.
Many countries don’t want to be bailed out by rich nations any more – they want trade rights.
So far, though, the US has joined the list of countries that have opposed efforts to find additional funding from Europe, Japan and other rich countries.
Reversing the climate change
Science has shown that the effects of CFCs on the environment are far too strong to be excused.
Other CFCs – carbonaceous chlorine – were used before 1987, but still put people and the environment at risk, given their more potent effect on the climate.
The measures taken to save the ozone have been very effective, but even then it is unlikely that they will be sufficient to reverse the projected impact of global warming.