Unknown source ramps up ozone-destroying CFC production


Modelling shows CFC decline has slowed – and no one knows why. Andrew Masterson reports.


Some posters drawn by school children in India, urging action to repair the ozone layer.
Some posters drawn by school children in India, urging action to repair the ozone layer.
INDRANIL MUKHERJEE/AFP/Getty Images

Alarming findings published in the journal Nature seem set to trigger a global hunt for a hidden production plant that appears to be pumping out truly massive amounts of a chlorofluorocarbon (CFC) that was supposedly phased out completely in an effort to protect the Earth’s ozone layer.

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.

The researchers show that CFC-11 levels, measured at a number of remote monitoring sites around the world, decreased in line with expectations between 2002 and 2011. In 2012, however, the rate of decline suddenly reduced by about 50% – indicating that new source of production had started up.

The standard reference for CFC concentrations, the United Nations Environment Program’s Handbook for the Montreal Protocol, reported in its 2012 edition that production of CFC-11 was very close to zero.

This, suggests Montzka’s team, leads to a disturbing conclusion.

“The increase in emission of CFC-11 appears unrelated to past production,” the authors note. “This suggests unreported new production.”

And it seems to be new production on a huge scale. The researchers’ modelling indicates that since 2012 CFC-11 pumped into the atmosphere has increased by 13 gigagrams – 13,000 tonnes – per year.

“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.

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.

Each edition of the UN’s Handbook for the Montreal Protocol contains on its cover the sentence, The first treaty ever to achieve universal participation. If the findings of Montzka’s stand up to scrutiny, that boast may now turn out to be hollow.

  1. http://nature.com/articles/doi:10.1038/s41586-018-0106-2
  2. http://www.pnuma.org/ozono/Documentos/MP-Handbook-2012.pdf
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