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Why Is an Ozone-Destroying Chemical Coming Back, and How Do We Stop It?

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The ozone hole, which we’ve previously described as the “quintessential ‘80s problem” became alarmingly relevant again this week. Scientists reported that emissions of trichlorofluoromethane (CFC-11), an ozone-destroying substance banned under the Montreal Protocol, have apparently been rising since 2012. Despite a global treaty prohibiting CFC-11's use, someone’s breaking the law.

So, why is someone fucking with our ozone layer, and how do we stop them?

Data from 12 atmospheric observatories around the world showed CFC-11 levels in our atmosphere had been declining at a steady clip for years as the banned substance once widely used in refrigerators, air conditioning units, and foaming devices slowly decays out. But after 2012, the decline began to slow, consistent with a new source of about 14,000 tons of CFC-11 per year.


While that’s a small number compared with the CFCs we were pumping out in the heydey of hairspray, Steve Montzka, lead author of the study published in Nature, told Earther via email that if the emissions persist, recovery of the ozone hole could be delayed “by about a decade.”

“This is really the first non compliance story that I’ve seen since the [Montreal] Protocol was signed,” Susan Strahan, an atmospheric chemist at NASA who wasn’t involved in the new research, told Earther.


It’s tough to imagine that someone would deliberately manufacture an illegal CFC, when there are readily available substitutes for most applications. But Montzka pointed out that CFCs aren’t necessarily being made on purpose.

“The chemical industry produces thousands of tons of chlorinated and fluorinated methanes for many purposes, like making teflon, PVC, solvents, etc,” he wrote. “This process could produce CFC-11 if not done carefully.”

It’s also conceivable that there’s been a dramatic uptick in use or destruction of the CFC “bank”—old refrigerators, air conditioning units, and fire extinguishers—although Montzka and his colleagues consider this scenarios pretty unlikely.

Whatever the reason, we won’t find it until we can pinpoint the source of the new CFC-11. So far, emissions data from a Hawaiian observatory suggests the culprit lies somewhere in east Asia, a huge and populous geographic region.


Fortunately, there’s more data at our disposal and readily collectible that could shed light on the matter. Montzka noted that China, South Korea, and Japan all have long-term measurement records “that, once analyzed, will likely help us pinpoint the location of this increased source.”

Aircraft missions could also help. “NASA has aircraft with all kinds of cool instruments that’ll measure exactly how much of a given CFC is there,” Strahan said, pointing to the pollution-sniffing ATom mission as one example. “If you suspect it’s in a certain region, you could go fly over, or downstream.”


CFC-11 is part of a family of chlorofluorocarbons or freons that were once widely used in a range of applications, until we realized that they were creating a giant hole in the ozone layer. World leaders decided to ban them with a global treaty that phased out CFCs during the ‘90s and aughts.

And for a while, it looked it like was working. Concentrations of ozone-destroying chlorine have been falling in the atmosphere, and the ozone hole is slowly healing.


Hopefully, scientists can track down the culprit of the new emissions soon, and the international community can figure out how to snuff them out. But that raises to another issue: How do you enforce a 30 year old treaty nobody’s ever violated?

“What would be done about it I don’t know,” Strahan said. “It’s not like there is a Montreal Protocol police.”