Climate science: Emissions from CFC banks could delay ozone recovery

Emissions of chlorofluorocarbons (CFCs) from certain older applications still in use may be larger than previously thought, finds a study published in Nature Communications. These emissions could delay the recovery of the Antarctic ozone hole and contribute the equivalent of 9 billion metric tonnes of CO2 into the atmosphere.

Most states have agreed to stop the use of CFCs in production as defined by the Montreal Protocol. However, emissions from products already in use (CFC banks) continue. These include some refrigerators, air conditioning units and insulation foam. The recent unexpected rise in CFC-11 emissions highlights the need to quantify emissions from these banks in order to accurately assess the scale of emissions from renewed production.

Megan Lickley and colleagues use a new statistical framework to assess the size of CFC banks and their corresponding emissions of CFC-11, CFC-12 and CFC-113. They show that these are substantially larger than previous assessments have indicated and account for a large proportion of the current estimated emissions of CFC-11 and 12 (with the exception of increased CFC-11 emissions after 2012 owing to renewed production). The use of CFC-113 is still permitted in some applications under the Montreal Protocol, but the level of emissions reported here exceeds that of previous studies, raising questions about their sources. The authors estimate that emissions from current banks could delay the recovery of the ozone hole by up to 6 years and contribute the equivalent of about 9 billion metric tonnes of CO2 to the atmosphere. This finding highlights the need to recover and destroy CFC banks to reduce emissions, the authors conclude.