LONDON: You can’t see it with the naked eye but high above your head, just above the altitude at which the world’s highest-flying passenger jets soar, is a fragile layer of natural gas that shields all life on Earth from the deadly impacts of passengers. Ultraviolet radiation from the sun.

This is the ozone shield, a belt of gas – specifically ozone, or O3, which is made of three oxygen atoms – formed by the natural reaction of solar ultraviolet light with O2, the oxygen we breathe.

Without it, we would all be overcooked. In the words of the Ozone Secretariat of the United Nations Environment Programme, “Long-term exposure to high levels of UV-B radiation threatens human health and harms most animals, plants and microbes, therefore the ozone layer protects all life on Earth.”

But now, after decades of fighting to save it—and us—scientists have announced that the hole in the ozone layer, discovered in the 1980s, is healing.

This month’s announcement is a triumph for one of the greatest international scientific collaborations the world has ever seen. And as the world struggles to tackle climate change, this is a hugely timely and encouraging demonstration of what the international community can achieve when it really turns its attention to something.

As the nations of the world prepare to convene at the United Nations Climate Change Conference, COP 28, in the United Arab Emirates, where in November they are expected to count the progress they have made toward the climate change targets set by the 2015 Paris Agreement, the resounding success of The ozone-saving Montreal Protocol of 1987 can only serve as an inspiration.

The ozone layer and its role in absorbing the sun’s ultraviolet rays were first identified by two French physicists, Charles Fabry and Henri Poisson, in 1913, but it was not until 1974 that an article was published in the journal nature He warned us of the danger of its destruction.

Discovered by chemists. Sherwood Rowland, of the University of California, Irvine, and Mario Molina, of the Massachusetts Institute of Technology, found that man-made gases, such as chlorofluorocarbons, or CFCs, used in appliances and products such as refrigerators and aerosols, were destroying ozone.

In 1995, Rowland and Molina, together with Dutch scientist Paul Crutzen, were awarded the Nobel Prize in Chemistry “for their work in atmospheric chemistry, particularly with regard to the formation and decomposition of ozone.”

But, according to the Nobel Prize citation, “the real shock came” in 1985, when scientists from the British Antarctic Survey, which had been monitoring the Antarctic ozone layer since 1957, discovered “severe depletion of the Antarctic ozone layer.”

The size of the pinhole identified above the research stations Halley and Faraday in Antarctica appears to differ, which was initially a mystery.

It is now understood, BAS explains, “that during the polar winter, clouds form in the Antarctic ozone layer, and chemical reactions in the clouds activate ozone-destroying substances.

“When sunlight returns in the spring, these substances—mostly chlorine and bromine from compounds like CFCs and halons—take part in efficient catalytic reactions that destroy ozone by about 1 percent per day.”

The discovery “changed the world”. NASA satellites were used to confirm that “not only was the hole above British research stations, but it covered the entire Antarctica.”

This was the so-called “ozone hole,” and as Crutzen noted in his 1995 Nobel Lecture, “It was a close call.”

He said: “Had Joe Farman and his colleagues from the British Antarctic Survey not persevered with their measurements in the harsh Antarctic environment…the discovery of the ozone hole might have been greatly delayed and an international agreement to phase out CFC production might have been less urgent.” “.

It was the survey’s work that led to the Montreal Protocol on Substances that Deplete the Ozone Layer, an agreement adopted in 1987 that regulates the production and consumption of nearly 100 man-made chemicals designated as “ozone-depleting substances.”

“There were suggestions in the 1960s and 1970s that you could put gases into the atmosphere that would destroy ozone,” said atmospheric scientist Professor John Pyle, former chair of chemistry at the University of Cambridge and one of the four international co-chairs of the Protocol’s Scientific Assessment Panel. Montreal, for Arab News.

At the time, there was also concern about nitrogen oxides from high-flying supersonic aircraft, such as the Concorde, which could destroy the ozone layer.

But after Rowland and Molina published their paper, proposing that chlorofluorocarbon gases could rise high enough in the atmosphere to destroy ozone, there had been about a decade during which this was only a theoretical notion before, thanks to the British Antarctic Survey, ozone was discovered. hole “.

The global response, engineered by the United Nations and the World Meteorological Organization, was almost astoundingly swift.

The British Antarctic Survey paper was published in 1985, and by 1987 the Montreal Protocol had been agreed upon. In the words of the United Nations Environment Program: “The Protocol is one of the most successful environmental agreements of all time.

“What parties to the Protocol have been able to achieve since 1987 is unprecedented, and it continues to provide an inspiring example of what international cooperation at its best can achieve.”

Without a doubt, millions of people have lived longer, healthier lives thanks to the Montreal Protocol. In 2019, the U.S. Environmental Protection Agency estimated that in the United States alone, the protocol prevented 280 million cases of skin cancer, 1.6 million deaths, and 45 million cases of cataracts.

But the battle is not over yet. It will take another four decades for the ozone layer to fully recover, according to the latest quadrennial report from the UN-backed Scientific Assessment Panel for the Montreal Protocol on Substances that Deplete the Ozone Layer, which was published this month.

But according to the report “Scientific Assessment of Ozone Depletion: 2022”: “The phase-out of nearly 99 percent of banned ozone-depleting substances has successfully protected the ozone layer, resulting in a marked recovery of stratospheric ozone and a decline in human exposure to radiation The sun’s harmful ultraviolet rays.

If current policies continue in place, she adds, “the ozone layer is expected to return to 1980 values” — that is, before the ozone hole appeared — “by 2066 over the South Pole, by 2045 over the North Pole, and by 2040 for the rest of the world.”

This is “great news,” Meg Seki, Executive Secretary of the UNEP’s Ozone Secretariat, told Arab News. And it had the added benefit of fighting global warming.

In 2016, an additional agreement, known as the Kigali Amendment to the Montreal Protocol, resulted in a reduction in the production and consumption of hydrofluorocarbons, or HFCs, compounds introduced to replace banned CFCs but found to be powerful climate changers. Gases. It is estimated that by the year 2100, the Kigali Amendment will have helped prevent up to 0.5°C of global warming.

“The impact that the Montreal Protocol has had on climate change mitigation cannot be overstated,” Seki said. “Over the past 35 years, Protocol has become a true champion of the environment.”

It is also a shining example of what can be achieved in the fight against climate change.

September 16th of each year marks the United Nations International Day for the Preservation of the Ozone Layer. As António Guterres, Secretary-General of the United Nations, said while marking the occasion in 2021: “The Montreal Protocol…has done its job well over the past three decades. The ozone layer is on the way to recovery.”

He added, “The cooperation we’ve seen under the Montreal Protocol is exactly what we need right now to confront climate change, which is a similar existential threat to our societies.”