A surprising increase in the emissions of trichlorofluoromethane (R11) since 2012

In an article¹ published in the journal Nature, scientists from the National Oceanic and Atmospheric Administration reveal that the decline of the atmospheric concentrations of trichlorofluoromethane (also known as R11) was constant from 2002 to 2012, but then slowed by about 50% after 2012. According to a model analysis, there has even been an increase in R11 emissions of 13?±?5 gigagrams (about 13,000 tonnes) per year (25?±?13 %) since 2012, despite reported production being close to zero since 2006. This is inconsistent with the requirements of the Montreal Protocol, which instituted a total phase out of CFC production in 2010.

According to the researchers, this annual increase could not be explained by a possible atmospheric change or past production. They therefore suggest a new source of undeclared production, without knowing its origin. Faced with this violation of the Montreal Protocol, some sources report that an American observatory based in Hawaii has identified refrigerants from East Asia containing R11, without further details for the moment.

In a recent statement, the UN Environment observes that the continued increase in global emissions of CFC 11 would compromise the recovery of the ozone layer. The organization also notes that "it is crucial to identify the causes of these emissions and take necessary action".

¹ MONTZKA Stephen A. DUTTON Geoff S. YU Pengdei. An unexpected and persistent increase in global emissions of ozone-depleting CFC-11. Nature. 2018, vol 557, 5 p. Available online.

An article dealing with this subject is available in French on the RPF website.