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The cancer-causing hole in the ozone layer that was at one time Earth’s biggest environmental dilemma will have fully healed in about 40 years, a report out Monday shows.
A once-every-four-years United Nations scientific assessment of the ozone has found continued recovery during the more than three decades after all nations agreed to stop using the refrigerants and aerosols that arguably made life cooler and hair bigger, but spewed chemicals that ate away at the layer of ozone in Earth’s atmosphere.
That layer shields the planet from harmful ultraviolet rays linked especially to skin cancer, but also to cataracts and crop damage. Those chemicals included chlorofluorocarbons (CFCs) that were used as solvents and refrigerants, including in air conditioners.
This ban is “saving 2 million people every year from skin cancer,” United Nations Environment Programme Director Inger Andersen previously told The Associated Press.
The progress is slow, according to the report presented Monday at the American Meteorological Society convention in Denver, but not insignificant. It can take decades for nature to fully flush out the lingering chemicals that had been hurting the ozone layer.
Still, the previous loss of the ozone layer is on track to be completely recovered by 2040 across the world, aside from the polar regions, according to the report. The ozone layer will fully bounce back by 2045 over the Arctic and by 2066 over the Antarctic.
The hole in the ozone layer above Antarctica in satellite images over a 21-year period.
NASA/Reuters
Scientists and environmental advocates have long hailed the collective efforts to heal the ozone hole in a 1987 agreement called the Montreal Protocol. And they point to its efforts when trying to get more rich and developing nations alike to unite in slowing global warming.
Read: Rich nations are quitting their oil and gas habit too slowly, U.N. says in ’emissions gap’ report
“Ozone action sets a precedent for climate action. Our success in phasing out ozone-eating chemicals shows us what can and must be done — as a matter of urgency — to transition away from fossil fuels, reduce greenhouse gases (GHG) and so limit temperature increase,” World Meteorological Organization Secretary General Petteri Taalas said in a statement.
Still, scientists concede that there’s a greater challenge when it comes to GHGs like carbon dioxide. They linger in the atmosphere far longer and, unlike CFCs which were produced by just a handful of companies, the emissions from fossil fuels are far more widespread and embedded in most human activities, from driving to cooking. GHGs, which also include carbon dioxide and methane, can be spewed by the combustion of fossil fuels such as coal, oil
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Other chemicals that chew up the ozone are now found to be in lower levels in the atmosphere, the report said. Chlorine levels are down 11.5% since they peaked in 1993 and bromine, which is more efficient at eating the ozone but is at lower levels in the air, dropped 14.5% since its 1999 peak.
A few years ago emissions of one of the banned chemicals, CFC-11, stopped shrinking and was rising, the AP reported. Rogue emissions were spotted in part of China, but now have gone back down to where they are expected, the scientists said.
Read: Study suggests even short-term exposure to air pollution hurts older men’s thinking and memory
A third generation of those chemicals, called HFCs, was banned beginning a few years ago, but not for their ozone impact, rather for their climate-warming properties as a GHG.
The U.S. Senate voted to ratify an international treaty in September 2022 and join 137 other countries in agreeing to phase out HFCs climate-warming chemicals that were widely used as coolants in refrigerators, air conditioners and heat pumps.
The new report says that the HFC ban would avoid 0.5 to 0.9 degrees Fahrenheit (0.3 to 0.5 degrees Celsius) of additional warming.
Natural weather patterns in the Antarctic also affect ozone hole levels, which peak in the fall. And the past couple of years, the holes have been a bit bigger, but the overall trend is one of improvement, the scientists said.
The latest progress report includes a look at the potential impact on the ozone layer of solar geoengineering, a proposed climate intervention where reflective particles, such as sulfur, are sprayed into the atmosphere to deflect sunlight and therefore, reduce global warming. Federal U.S. money has gone into this research.
The U.N. report out Monday cautioned that efforts to artificially cool the planet by putting aerosols into the atmosphere to reflect the sunlight would thin the ozone layer by as much as 20% in Antarctica.
The Associated Press contributed.
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