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

Katie Ramirez
May 17, 2018

Emissions of CFC-11 have climbed 25 percent since 2012, despite the chemical being part of a group of ozone pollutants that were phased out under the 1987 Montreal Protocol.

Stephen Montzka from the US National Oceanic and Atmospheric Administration and a team of colleagues report that after a long and predicted decline, production of trichlorofluoromethane (CFC-11) - a substance responsible for the second largest destructive impact on the ozone layer - suddenly and mysteriously increased in 2012 and has continued to do so ever since. Samples acquired in Hawaii lead to speculation that the CFC-11 production may be happening in East Asia, but an exact source isn't clear at this time.

A simple model analysis of our findings suggests an increase in CFC-11 emissions ... despite reported production being close to zero4 since 2006 ...

CFCs were once widely used in the manufacture of aerosol sprays, as blowing agents for foams and packing materials, as solvents, and as refrigerants. Use of the chemical was banned in 2010 via the Montreal Protocol, an global agreement made to protect the environment.

"I do measurement for more than 30 years, and this is the most wonderful thing I have seen, said Steven Monda (Stephen Montzka), a scientist from the National oceanic and atmospheric administration, who led this work". "Further work is needed to figure out exactly why emissions of CFC-11 are increasing and if something can be done about it soon". A smaller amount of CFC11 also exists today in older refrigerators and freezers.

CFC-11 still contributes about a quarter of all chlorine - the chemical that triggers the breakdown of ozone - reaching the stratosphere. But the apparent increase in emissions of CFC-11 has slowed the rate of decrease by about 22 percent, the scientists found.

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.

The researchers said that the less rapid decline of CFC-11 could prevent ozone from returning to normal levels, or at least as quickly as hoped. Scientists say there's more of it - not less - going into the atmosphere and they don't know where it is coming from.

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The USA ceased production in 1996 and other countries agreed to phase out CFC production by 2010.

Either someone's making the banned compound or it's sloppy byproducts that haven't been reported as required, Montzka said.

As a result of the controls, CFC11 concentrations have declined by 15% from peak levels measured in 1993.

To put that in perspective, production of CFC-11, marketed under the trade name Freon, peaked at about 430,000 tons per year in the 1980s. "But this is most surprising one".

A chemical banned due to the harm it causes the ozone layer may be secretly in production somewhere in the world.

Keith Weller, a spokesman for the United Nations Environment Program, which helps implement the protocol, said the findings would be presented to the parties to the agreement for review.

"If the increased emissions were to go away [soon], it's influence on the recovery date for the ozone layer would be minor", he said.

The Montreal Protocol, signed by more than 200 countries and generally regarded as having a good record of compliance, is created to protect the Earth's ozone layer.

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