Restoring them is essential to human health, food security and the planet. Ultraviolet-B rays cause cancer and eye damage in humans. It also harms plants and prevents their growth and limits their ability to do so store Carbon dioxide that is heating the planet.
Scientists said the recovery of the ozone layer should serve as proof that societies can join forces to solve environmental problems and combat climate change.
“Ozone action sets a precedent for climate action,” WMO Secretary-General Petteri Taalas said in a statement. “Our success in phasing out chemicals that eat away at the ozone layer shows us what can and must be done — urgently — to transition away from fossil fuels, reduce greenhouse gases, and thus limit warming.”
At this rate, the report concluded, the ozone layer could recover to levels of the 80s in most of the world by the 2040s, and by 2066 in Antarctica. Ozone loss is most severe over the Antarctic, with an ozone “hole” appearing there each spring.
The scientists stressed that these improvements would not be static, given the natural fluctuations in ozone levels and the ozone-inhibiting effect of volcanic eruptions such as the massive eruption from the Pacific volcano Hongga Tonga a year ago.
But scientists said the latest ozone data and projections are nonetheless further evidence of the success of the Montreal Protocol, the 1987 global agreement to phase out the production and use of ozone-depleting substances.
Meg Seki, executive secretary of the UN Environment Programme’s Ozone Secretariat, called the results “wonderful news”.
The recent drop in detected levels of the chemical known as CFC-11, in particular – which was recently noted in 2018 at higher-than-expected levels and traced to China – is evidence that societies can come together to tackle a vexing environmental problem, said Martyn Chipperfield, a professor at the University of Leeds. Who serves on the scientific committee.
“It turned out to be another success story,” he said. “Communities came together and were dealt with.”
Ozone is a molecule made of three oxygen atoms, and it thrives in the stratosphere nine to 18 miles above Earth’s surface. It can exist at ground level as well, where it is caused by air pollution on hot summer days and is considered a health hazard. In the atmosphere, however, it acts as a primary shield that protects Earth’s life from harmful ultraviolet radiation.
In the same way that UV lights kill pathogens like the virus responsible for COVID-19, the sun’s radiation would make it impossible for life to thrive on Earth were it not for the protection of the ozone layer. Ultraviolet-B rays, a high-energy form of solar radiation, damage DNA in plants and animals, disrupting a variety of biological processes and reducing the efficiency of photosynthesis.
The Montreal Protocol, which has been approved by every country in the world, protects the ozone layer by banning the manufacture and use of substances that destroy it when they come into contact with it in the atmosphere. That largely includes a class known as chlorofluorocarbons or CFCs, which contain ozone-depleting chlorine and are used in refrigerators, air conditioners and aerosol cans.
The treaty was expanded in 2016 through the Kigali Amendment to include hydrofluorocarbons, or hydrofluorocarbons, an alternative to CFCs that do not harm the ozone but are a type of greenhouse gas that warms the planet more powerfully than carbon dioxide. U.S. congress It ratified the amendment in September.
The report, presented Monday morning at the American Meteorological Society’s annual meeting in Denver, found that the world is also making progress in curbing greenhouse emissions.
“We can already see HFCs Paul Newman, one of the four co-chairs of the Montreal Protocol’s Scientific Assessment Panel, said:
However, it is possible that upcoming data on ozone levels will raise some concerns that the ozone layer is not recovering as quickly as the report concluded, he said. Newman said he expects it to be due to the eruption of Hong Tonga It blew a lot of material into the atmosphere. Volcanic eruptions are known to accelerate the depletion of the ozone layer.
Newman said progress would likely slow if humans sought to geoengineer to reverse global warming by injecting sunlight-reflecting particles into the upper atmosphere. The panel, which looked at the potential impact of this practice for the first time in a report on Monday, found that depending on the timing, frequency and quantity of these injections, the particles could alter aspects of atmospheric chemistry important in the development of ozone.
“The Antarctic ozone hole is the first picture of ozone layer depletion,” Newman said. “Injecting stratospheric aerosols will probably make it a little worse.”
An earlier version of this article incorrectly referred to HFCs as HCFCs. They are known as HFCs. The article has been corrected.