For decades, Earth’s ozone layer, which protects life on our planet from the sun’s harmful ultraviolet (UV) rays, has been damaged by common chemicals used in everything from refrigerants to hairspray. But now the holes in the ozone layer are shrinking, thanks to decades of global efforts to restore it. This is evidenced by the data of the World Meteorological Organization (WMO), reports The Verge.
Scientists first discovered a hole over Antarctica in 1985. A couple of years later, countries around the world adopted the Montreal Protocol, a global effort to phase out ozone-depleting substances. Now, thanks to this work, scientists expect the ozone layer to begin to look more like its normal healthy state within the next decade. This reduces the risk of skin cancer and cataracts in humans, as well as sun damage to plants and crops.
By about 2066, according to the WMO, the ozone layer over Antarctica will return to what it was in 1980 – before this hole. Because ozone depletion was the strongest there, other areas are expected to recover more quickly.
In the north over the Arctic, the ozone layer should look like it did in 1980 by 2045. For the rest of the world, this recovery is expected by 2040. The UN Panel of Experts presented these conclusions at the annual meeting of the American Meteorological Society. Of course, this progress depends on policies that limit the use of harmful ozone-depleting substances.
Ozone molecules in the stratosphere absorb harmful ultraviolet radiation from the Sun, preventing it from reaching us. This is part of the process of continuous creation and destruction of ozone in our atmosphere. But when certain chemicals get there, this balance is disrupted, causing more ozone to be destroyed than formed.
Some of the worst offenders are chlorofluorocarbons (CFCs) once used in refrigeration, air conditioning, aerosol sprays, and a host of other products. Then there are hydrochlorofluorocarbons (HCFCs), developed as less potent replacements for CFCs that nevertheless still chewed through the ozone layer. Fortunately, by now, the Montreal Protocol has succeeded in phasing out about 99 percent of ozone-depleting substances.
A global agreement to protect the ozone layer is also useful for efforts to slow climate change. Ozone-depleting substances have been replaced by another class of chemicals that are potent greenhouse gases called hydrofluorocarbons (HFCs). The Kigali Agreement was added to the Montreal Agreement in 2016 to limit these planet-warming chemicals.
A worldwide phase-out of HFCs is expected to significantly reduce global warming by up to half a degree Celsius by 2100. For context, the world has already warmed by about 1.2 degrees Celsius since the pre-industrial era, exacerbating many of the extreme weather events we face today.
But along with the good news comes a climate warning. A panel of experts warns that “geoengineering” — the deliberate manipulation of the climate and/or atmosphere to undo some of the damage we’ve done by burning fossil fuels — could potentially have consequences for the ozone layer. They are particularly concerned about a tactic called stratospheric aerosol injection (SAI).
Proponents of this tactic believe it could help cool the planet because aerosols can reflect some sunlight back into space. SAI “comes with significant risks and can cause unintended consequences,” according to a recent report prepared with the support of WMO. And some climate experts have already sounded the alarm through recent attempt by one startup to release reflective sulfur particles into the stratosphere.
Meanwhile, the phase-out of ozone-depleting chemicals is seen as an example of what humans can achieve when they work together to overcome the global environmental crisis.
“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 and so limit temperature increase,” WMO Secretary-General Petteri Taalas said.