How the world has already prevented much worse warming in this century

But the virtues of the agreement, finally ratified by all countries, are more widespread than its impact on the hole in the ozone layer. Many of these chemicals are also powerful greenhouse gases. Thus, as a major side benefit, their reduction over the past three decades has already mitigated warming and could reduce by up to 1 C lower on global average temperatures by 2050.

Now a new study in Nature highlights another crucial, albeit unintended, bonus: reducing the pressure that the sun’s ultraviolet rays exert on plants, inhibiting photosynthesis, and slowing growth. The Montreal Protocol prevented “a catastrophic collapse of forests and croplands” that would have added hundreds of billions of tonnes of carbon to the atmosphere, said Anna Harper, senior lecturer in climatology at the University of Exeter and co-author of the article. in an email.

The Nature article, published on August 18, found that if the production of ozone-depleting substances had continued to increase by 3% each year, the additional UV radiation would have reduced the growth of trees, grasses, plants ferns, flowers and crops around the world.

The world’s plants are said to absorb less carbon dioxide, releasing up to 645 billion tonnes of carbon from the earth into the atmosphere this century. This could lead to global warming up to 1 C higher during the same period. It would also have devastating effects on crop yields and food supplies around the world.

The impact of increasing CFC levels on plants, along with their direct warming effect in the atmosphere, may have caused temperatures to rise by about 2.5 ° C during this century, all at the same time more of the already disastrous global warming projections for 2100, the researchers discovered.

“While originally conceived as an ozone layer protection treaty, the Montreal Protocol has been a very successful climate treaty,” says Paul Young, climatologist at Lancaster University and other author of the article.

All of this begs a question: why can’t the world adopt such an aggressive and effective international treaty designed explicitly to tackle climate change? At least some researchers believe there are crucial but largely overlooked lessons in the success of the Montreal Protocol, which are again becoming relevant as global warming accelerates and the next United Nations climate conference approaches. .

A fresh look

At this point, the planet will continue to warm up over the next several decades, no matter what, as the say UN climate report warned last week. But the worsening of the situation still strongly depends on how aggressively climate pollution can be reduced over the coming decades.

To date, countries have failed, through both the Kyoto Treaty and the Paris Climate Agreement, to reach an agreement with sufficiently ambitious and binding commitments to phase out emissions from carbon dioxide. greenhouse gas. The countries will meet at the next United Nations conference in Glasgow in early November, with the explicit aim of stepping up these goals under the Paris agreement.

Scientists wrote long papers and whole books reviewing lessons from the Montreal Protocol, and commonalities and differences between the respective efforts on CFCs and greenhouse gases.

A common opinion is that the relevance is limited. CFCs were a much simpler problem to solve as they were produced by a single industry, mainly by a few large companies like DuPont, and used in a limited set of applications.

On the other hand, almost all components of every sector of every nation emit greenhouse gases. Fossil fuels are the energy source that drives the global economy, and most of our machines and physical infrastructure are built around them.

But Edward Parson, professor of environmental law at the University of California, Los Angeles, says it’s time to take a fresh look at the lessons of the Montreal Protocol.

Indeed, as the dangers of climate change become more evident and dire, more countries are pushing for stricter rules, and companies are getting closer and closer to the stage than those like DuPont have. fact: move from steadfastly challenging scientific findings to reluctantly accepting that new rules were inevitable, so they had better understand how to operate and profit from them.

In other words, we are reaching a point where adopting more binding rules may be feasible, so it is crucial to use the opportunity to create more effective ones.

Strict rules, applied consistently

Parson is the author of Protecting the ozone layer: science and strategy, a detailed history of the Montreal Protocol published in 2003. It points out that the phase-out of ozone-depleting compounds was a more complex problem than often imagined, as a significant portion of the global economy depended on it one way or another.

He adds that one of the most persistent misconceptions about the deal is the idea that the industry had already developed alternative products and was therefore more willing to accept the deal in the end.

On the contrary, the development of alternatives occurred after the regulation was put in place. Rapid innovation continued as the rules got tougher, and industry, experts and technical bodies determined how much progress could be made and how quickly. This has produced ever more and better alternatives “with repeated positive feedback,” Parson says.

The prospect of lucrative new markets also helped. Many of these companies ended up making a lot of money by switching to new products.

This suggests that the world shouldn’t wait for innovations that will make tackling climate change cheaper and easier. Countries must implement rules that increasingly reduce emissions, forcing industries to find cleaner ways to generate energy, grow food, produce products and move things and people in the whole world.

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