Mysterious rise in banned ozone-destroying chemical shocks scientists

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

Mysterious rise in CFC11 emissions

Emissions of one of the chemicals most responsible for the Antarctic ozone hole are on the rise, despite an global treaty that required an end to its production in 2010, a new NOAA study shows.

"We show that the rate of decline of atmospheric CFC-11 was constant from 2002 to 2012, and then slowed by about 50 percent after 2012", an worldwide team of scientists concluded in a study. CFC-11 was once commonly used in insulating foams, but it's now banned under the Montreal Protocol and reported production is close to zero.

The finding seems likely to prompt an global investigation into the mysterious source. A smaller amount of CFC11 also exists today in older refrigerators and freezers.

Given that the boost in output will inevitably slow the planet's ozone layer recovery, discovering the source of the new production would seem an urgent priority.

The issue involves a gas called CFC-11, a chlorofluorocarbon that contributes to the depletion of the ozone layer. The source of the new emissions has been tracked to east Asia, but finding a more precise location requires further investigation.

"The reduction in the atmospheric concentration of trichlorofluoromethane (CFC-11) has made the second-largest contribution to the decline in the total atmospheric concentration of ozone-depleting chlorine since the 1990s", the new research says.

"We are acting as detectives of the atmosphere, trying to understand what is happening and why", Montzka said.

CFC-11, used primarily for foams, can last up to 50 years in the atmosphere once it is released.

Nearly no CFC-11 has been been produced since 2006 - or so we thought.

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.

Keith Weller, a spokesman for the U.N. Environment Program, which administers the Montreal Protocol, said the findings would have to be verified by the scientific panel to the protocol and then would be put before the treaty's member countries. "It is critical that we take stock of this science, identify the causes of these emissions and take necessary action", he said. "But we don't know of any folks who are destroying buildings at a much more dramatic rate than they were before", said Montzka.

The Montreal Protocol has been effective in reducing ozone-depleting gases in the atmosphere because all countries in the world agreed to legally binding controls on the production of most human-produced gases known to destroy ozone.

"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. "I have a feeling that we will find out fairly quickly what exactly is going on and that the situation will be remedied", he said. However, that decrease is significantly slower than it would be without the new CFC emissions.

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