Scientists Warn Ozone-Depleting CFCs Are Back And Are Coming From ‘Mystery’ Source

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All along, it was widely thought that chlorofluorocarbons, or CFCs, were a thing of the past more than three decades after the historic Montreal Protocol was signed. But a new study led by researchers from the National Oceanic and Atmospheric Administration suggests that these ozone layer-depleting CFCs are back with a vengeance, with precious little information known about the company that might be producing the chemical.

According to a report from NPR, the key takeaway from this “scientific whodunit” is that atmospheric levels of trichlorofluoromethane (CFC-11) are dropping, but not as quickly as what one would expect with its production phased out as of the start of the decade. Although researchers have traced the rogue emissions to a source in eastern Asia, nothing else is known about this source — not the name of the company, not its exact location.

In a news release published by EurekAlert, the researchers noted that CFC-11 is the second most common form of ozone-depleting gas in Earth’s atmosphere, and a part of the CFC family whose specific production had officially ceased in 2010, per the terms of the Montreal Protocol. CFCs in general once had several applications and were mainly used as refrigerants, packing materials, blowing agents for foams, and in the production of aerosol sprays.

Despite CFC-11 production ending almost a decade ago, the news release stressed that a “large reservoir” of the chemical is still found in foam insulation in buildings and appliances manufactured prior to the mid-1990s, with a smaller amount of the ozone-depleting agent also found in chillers, even up to this day. Although it is expected that our planet’s ozone hole will close sometime in the middle of the century, this possibility is contingent on CFC-11 emissions declining substantially, and no production of the chemical taking place.


Unfortunately, the researchers noticed some troubling trends in their study, observing that CFC-11 emissions are, in fact, increasing due to the aforementioned mystery source. While its atmospheric levels are still declining, those figures aren’t decreasing at the rate they’re expected to and appear to be slowed down by the newly discovered source of CFC emissions. Based on data taken from 12 sites around the world, CFC-11 emissions started ticking up once again at 2012, just two years after production was supposed to halt completely.

“We’re raising a flag to the global community to say, ‘This is what’s going on, and it is taking us away from timely recovery from ozone depletion,'” said NOAA’s Stephen Montzka, who led a multinational team of scientists in authoring the new study.

“Further work is needed to figure out exactly why emissions of CFC-11 are increasing and if something can be done about it soon.”

With Montzka and his colleagues unsure whether the mystery source of the emissions is deliberately violating the Montreal Protocol or not, University of California, San Diego professor of international relations David Victor told NPR that it would be difficult to enforce the necessary sanctions against the source. He said that the Montreal Protocol’s enforcement mechanism “doesn’t really have any teeth,” and that countries or firms who willfully violate the terms of the treaty “can probably do that” no matter how often reports are filed.