The shrinking hole is a powerful reminder that multinational cooperation can solve big environmental ills.
From shrinking sea ice to deadly air pollution, it seems there's never a shortage of bad news about the environment. But now comes some very good news — in the form of satellite data showing that the worrisome ozone hole in the atmosphere over Antarctica is slowly healing.
The data, from NASA's Earth-orbiting Aura satellite, indicate that depletion of the protective ozone layer over Antarctica was about 20 percent lower during the 2016 Antarctic winter (early July to mid-September) than during the same period in 2005.
Experts say the mending of the hole is attributable to series of international regulations on chlorofluorocarbons (CFCs) — the manmade chemicals known to promote the breakdown of ozone molecules (O3) — that were adopted beginning in 1987. CFCs were once found in aerosol sprays, refrigerants, solvents, and other products.
"We may have turned the corner on O3 depletion," Dr. Susan Strahan, an atmospheric scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and the lead author of a paper about the satellite data, told MACH in an email. "But it's important that all the nations of the world continue to abide by the Montreal Protocol (and its amendments) that ban CFC production."
Strahan said the recovery would continue at a slow pace because CFCs are long-lived molecules that persist in the atmosphere for decades. "We hope to see the O3 hole gone between 2060 and 2080," she added.
Experts say any rise in atmospheric ozone levels brings major benefits. Ozone blocks ultraviolet radiation from the sun, which can cause health problems ranging from cataracts and other eye problems to premature skin aging and potentially fatal skin cancers. The Skin Cancer Foundation calls ozone depletion "a serious health threat."
"There's also some evidence that increased solar UV radiation can adversely affect crop yields, with consequent effects to the food chain," Dr. David Rowley, a senior lecturer in physical chemistry at University College London and a noted expert on atmospheric chemistry, told MACH in an email.
But the best thing about the mending of the ozone hole may be that it serves as a reminder that international efforts to protect the environment can pay off in a big way.
Last November, on the 25th anniversary of the "World Scientists' Warning to Humanity," more than 15,000 scientists from 184 countries issued a "Second Notice" to encourage the world community to take urgent action against climate change and other environmental problems. As Newsweek reported, the scientists pointed to previous research suggesting that the ozone hole was shrinking and noted that "the rapid global decline in ozone-depleting substances shows that we can make positive change when we act decisively."
In the midst of the new satellite data, Strahan offered enthusiastic support for that conclusion. "Science and policy CAN work together to solve global problems," she told MACH. "I think people need to know this so they won't be discouraged about solving climate change."
The paper was published Jan. 4 in the journal Geophysical Research Letters.