There's been a mysterious rise in ozone-destroying emissions

Pablo Tucker
May 17, 2018

Launching a balloon that carries atmospheric measuring devices over Antarctica.

Emissions of one of the chemicals most responsible for the Antarctic ozone hole are on the rise, despite an worldwide treaty that required an end to its production in 2010, a new NOAA study shows. This was partly because nations had all agreed to ban or phase out CFCs, which are short for "chlorofluorocarbons" but are simply called "ozone-depleting substances", due to an global treaty back in the 1980s called the Montreal Protocol.

"It's the most surprising and unexpected observation I've made in my 27 years", said lead author Stephen Montzka, a research chemist at NOAA.

There is a small chance that there is a more innocent explanation for the rise in CFC-11 emissions, the scientist say.

Widely used in 1970s and 1980s as propellant in aerosol sprays, as well as in refrigeration and air conditioning systems, CFCs do not exist in nature.

The scientists say that the increase is likely a result of new, unreported production of the gas, known as CFC-11, probably in East Asia.

The slowdown in reduction of CFC-11 also has implications for the fight against climate change. They found that the difference in CFC-11 concentrations between the northern and southern hemispheres has been increasing, which points to a northern hemisphere source. This means that the total concentration of ozone-depleting chemicals, overall, is still decreasing in the atmosphere.

However, if no action is taken on the new source of emissions, it could be highly significant. But the researchers noticed the rate at which it is declining appeared to be slowing down. In 2012, however, the rate of decline suddenly reduced by about 50% - indicating that new source of production had started up. After considering a number of possible causes, Montzka and his colleagues concluded that CFC emissions must have increased after 2012. "Further work is needed to figure out exactly why emissions of CFC11 are increasing, and if something can be done about it soon".

The researchers are puzzled as to what the motivation for any unauthorised new production might be. That's why National Ocean and Atmospheric Administration researchers were surprised to discover it's increased in the atmosphere by 25 percent since 2012. Emissions of this CFC to the atmosphere reached about 386,000 tons per year at their peak later in the decade.

"This is 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", they note.

"If these emissions continue unabated, they have the potential to slow down the recovery of the ozone layer", Weller said in a statement.

Keith Weller, a spokesman for the United Nations Environment Program, which administers the Montreal Protocol, said the findings will have to be verified by the scientific panel to the Protocol, and then would be put before the treaty's member countries.

But Mr. Doniger noted that the Montreal Protocol, which has been signed by almost 200 countries, has a strong track record of compliance, with countries often reporting their own violations.

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