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Banned ozone-destroying chemical makes a mysterious resurgence

17 May 2018

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.

The rise in CFC-11 was revealed by Stephen Montzka, at the US National Oceanic and Atmospheric Administration (NOAA) in Colorado, and colleagues who monitor chemicals in the atmosphere.

Zaelke said he was surprised by the findings, not just because the chemical has always been banned but also because alternatives exist, making it hard to imagine what the market for CFC-11 today would be.

"These considerations suggest that the increased CFC-11 emissions arise from new production not reported to [the U.N. Environment Program's] Ozone Secretariat, which is inconsistent with the agreed phase-out of CFC production in the Montreal Protocol by 2010", the researchers wrote.

CFC chemicals were used in making foams for furniture and buildings, in aerosols and as refrigerants. The last option is a possibility, as if the new CFC-11 is being used in foams, then only a small fraction will have made it to the atmosphere so far and more could leak out for many years into the future. The researchers' modelling indicates that since 2012 CFC-11 pumped into the atmosphere has increased by 13 gigagrams - 13,000 tonnes - per year. Though concentrations of CFC11 in the atmosphere are still declining, they're declining more slowly than they would if there were no new sources, Montzka said. Even more unexpected was that the rate of decline slowed by 50 percent after 2012.

While the new analysis can't definitively explain why emissions of CFC11 are increasing, but Montzka suspects covert production.

Lastly, the team considered whether the new CFC-11 was being produced as a by-product of some other chemical manufacturing process.

Montzka said the world's nations are committed to its enforcement.

Emissions of CFC-11 increased by 25 percent in 2012, despite the fact that the chemical substance is part of a group of pollutants for ozone, which were banned under the Montreal Protocol of 1987. But they were banned under the global Montreal protocol after the discovery of the ozone hole over Antarctica in the 1980s.

The findings of Montzka and his team of researchers from the Cooperative Institute for Research in Environmental Sciences (CIRES), the United Kingdom, and the Netherlands, represent the first time that emissions of one of the three most abundant, long-lived CFCs have increased for a sustained period since production controls took effect in the late 1980s.

If the source of these emissions can be identified and mitigated soon, the damage to the ozone layer should be minor.

David Doniger, director of the climate and clean energy program of the Natural Resources Defense Council, an environmental group in Washington, said the new emissions were "bad for the ozone layer and bad for climate change".

Unless the culprit is found and stopped, the recovery of the ozone layer, which protects life on Earth from damaging UV radiation, could be delayed by a decade. "It is therefore imperative that this finding be discussed at the next Ministerial meeting of Governments given recovery of the ozone layer is dependent on all countries complying with the Montreal Protocol (and its adjustments and amendments) with emissions globally dropping to zero".

Banned ozone-destroying chemical makes a mysterious resurgence