The volume of five ozone-depleting CFCs in the atmosphere increased rapidly between 2010 and 2020, reaching a record high.
CFCs, or chlorofluorocarbons, were commonly used in refrigerators, aerosols and solvents until their production was banned globally after it was discovered they were the primary drivers of damage to the ozone layer.
The Montreal protocol, agreed in 1987, required a rapid phase-out of some CFCs and a slower phase-out of others. In 2000, the use of CFCs was banned entirely in all new fridges and freezers in the UK.
However, CFCs are still permitted to be released as feedstocks – raw materials used to produce another compound – intermediates and by-products in the production of other chemicals. CFCs produced this way are not covered by the protocol.
Three of the CFCs measured (CFC-113a, CFC-114a, CFC-115) are known to be used in the production of chemicals, but there are no known uses for the remaining two (CFC112a and CFC-113).
The authors of the study, published today in Nature Geoscience, estimate that the combined emissions of the five CFCs in 2020 was the equivalent of 4,200 tonnes of CFC-11, the second-most abundant chlorofluorocarbon.
In terms of the warming effect, the authors suggest this amounted to 47million tonnes of CO2, equivalent to 150% of London’s CO2 emissions in 2018.
While the impact of accumulative emissions of these five CFCs between 2010 and 2020 on the ozone layer is small, the authors warn a continuous increase at the current rate could offset some of the progress made under the Montreal Protocol – and may have additional climate impacts.
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