Global emissions of five controlled CFCs have increased since 2

Abstract

Production and consumption of ozone-depleting chlorofluorocarbons (CFCs) are controlled under the Montreal Protocol. CFC production for most applications was banned globally in 2010, albeit with exemptions for uses assumed to cause negligible emissions to the atmosphere, such as in the production of other chemicals. A few years ago, emissions of CFC-11 were reported to be increasing after their phase-out, most likely due to unreported production and non-compliance, which sparked widespread, renewed attention to this topic. Here we show that emissions of five other CFCs have increased since 2010, namely CFC-13, CFC-112a, CFC-113a, CFC-114a and CFC-115. Three of these CFCs are likely increasing due to their involvement in the production of non-ozone-depleting HFCs, which have largely replaced CFCs and HCFCs in many applications. The drivers behind the increase in the other two CFCs is unclear. While the impact of these CFCs on ozone layer recovery will likely be small, these long-lived CFCs are potent greenhouse gases and their CO2-equivalent emissions in 2020 were comparable to those of a mid-sized European country.