The world agreed to ban this ozone killer years ago--but it looks like someone is making more

[Rhiannon12866]

CFC-11 isn't leaving the atmosphere as quickly as it should.

The ozone layer has made an impressive recovery in the last 30 years, but that has never been a foolproof plan. A new study published in the journal Nature on Wednesday illustrates a shocking spike in emissions for an ozone-depleting chemical banned by international treaty decades ago. The culprit who is generating this pollutant is still unknown and at large.

“We were shocked, no doubt,” says Stephen Montzka, a scientist with the National Oceanic and Atmospheric Administration and lead author of the new study. “We couldn’t understand how on Earth emissions would be increasing when production had been zero for so long.”

The chemical, CFC-11, is part of a class of substances called chlorofluorocarbons (CFCs) once hailed as a pinnacle of 20th century industrial chemistry. CFCs showed up in refrigerators, aerosol cans, and solvents of all kind. They were everywhere, like some sort of miracle compound specifically designed for modern consumerism.

Then scientists started realizing that CFCs were widening a gaping hole in the Earth’s ozone layer, an essential shield for life on this planet against the sun’s harmful ultraviolet radiation. CFCs’ chlorine molecules initiate ozone-destroying chemical reactions and allow UV radiation through to the surface. The world came together in 1987 to sign the Montreal Protocol, a pact that effectively banned all ozone-depleting substances, including CFCs. Signed by every nation in the U.N., “the Montreal Protocol is famous for being the world’s most successful environmental treaty,” says Durwood Zaelke, the founder and president of the Institute for Governance and Sustainable Development. “It’s done more than any other treaty to protect the climate. It’s kept the climate system from disaster.”

That’s part of the reason the new Nature study is so jarring: it’s a clear indication of the treaty’s violation. Whether that’s intentional or accidental is still unclear, but it nevertheless puts the Montreal Protocol’s parties on high alert.


More: https://www.popsci.com/cfc-ozone-emission



Staff at the South Pole get ready to release a balloon that will carry an ozone instrument up to 20 miles in the atmosphere, measuring ozone levels all along the way. NOAA