Banned Ozone-Harming Gas Creeps Back, Suggesting a Mystery Source

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"I do measurement for more than 30 years, and this is the most awesome thing I have seen, said Steven Monda (Stephen Montzka), a scientist from the National oceanic and atmospheric administration, who led this work". A US observatory in Hawaii found CFC-11 mixed in with other gases that were characteristic of a source coming from somewhere in east Asia, but scientists could not narrow the source down any further.

The forbidden emissions, ozone-depleting chemicals grow, said Wednesday a group of scientists, suggesting that someone may secretly produce a pollutant in violation of global agreements.

Scientists have detected an unexpected rise in atmospheric levels of CFC-11, a chlorofluorocarbon (CFC) highly damaging to the ozone layer.

"This evidence strongly suggests increased CFC-11 emissions from eastern Asia after 2012".

An ozone depleting CFC refrigerant, thought to be virtually extinct following Montreal Protocol phase outs, has mysteriously reappeared in increasing amounts in the atmosphere. "Further work is needed to figure out exactly why emissions of CFC-11 are increasing and if something can be done about it soon".

Banned by the Montreal Protocol in 1987, CFC-11 was seen to be declining as expected but that fall has slowed down by 50% since 2012.

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CFC-11 still contributes about a quarter of all chlorine - the chemical that triggers the breakdown of ozone - reaching the stratosphere. However, that decrease is significantly slower than it would be without the new CFC emissions.

The new study published on Wednesday shows that, as expected, the rate of decline of concentrations of CFC-11 observed was constant between 2002 and 2012.

It is possible that the increased emissions could be due to older buildings being demolished, but that doesn't seem to be the case.

Officially, production of CFC-11 is supposed to be at or near zero - at least, that is what countries have been telling the United Nations body that monitors and enforces the Protocol.

However, if no action is taken on the new source of emissions, it could be highly significant.

"You are left with, boy, it really looks like somebody is making it new", said Montzka, who noted that the less damaging replacement for CFC-11 is more expensive to make. Scientists say there's more of it - not less - going into the atmosphere and they don't know where it is coming from. CFC-11 concentrations have declined by 15 percent from peak levels measured in 1993 as a result.

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Today, the "hole in the ozone" over the South Pole is showing clear signs of recovery.

"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.

"The ozone layer remains on track to recovery by mid-century", the UN Environment Programme (UNEP) said in a statement, reacting to the findings.

Overall, it is important to underscore that the ozone layer is slowly recovering and ozone-depleting substances are still declining.

"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".

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