Media release

From: Springer Nature

Environment: Five ozone-depleting CFCs reached record-high abundance in 2020 *PRESS BRIEFING*

The atmospheric abundance and emissions of five ozone-depleting chlorofluorocarbons (CFCs), increased rapidly between 2010 and 2020, according to a paper published in Nature Geoscience. The study suggests these increased emissions are mainly from processes that are not subject to current controls under the Montreal Protocol.

CFCs were commonly used as refrigerants, aerosol propellants, solvents, and foam-blowing agents, but were found to be the primary driver of damage to the ozone layer. Their production was banned globally in 2010 under the Montreal Protocol. However, CFCs can still be released as feedstocks (raw materials used to produce another compound), intermediates and by-products during the production of other chemicals, such as hydrofluorocarbons (HFCs), which are substitutes for CFCs used in refrigeration and air-conditioning.

Luke Western and colleagues examined how the atmospheric abundance of five CFCs (CFC-113, CFC-112a, CFC-113a, CFC-114a, CFC-115), with few or no known current uses, changed between 2010–2020 using measurements from 14 sites, globally. They find that the atmospheric concentration of the five CFCs has increased since 2010 and reached a record-high abundance in 2020. While little to none of these CFCs are expected to exist in old appliances or building foams, the authors indicate that CFC-113a, CFC-114a and CFC-115 are known to be involved in the production of other chemicals. There are no known current uses for CFC-112a and CFC-113 and the origins of the increases for these chemicals are uncertain, the authors note. They 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 47 million tonnes of CO2, which they indicate is the same as 150% of London’s CO2 emissions in 2018.

The authors suggest that the impact of accumulative emissions of these five CFCs between 2010 and 2020 on the ozone layer is small. However, a continuous increase at the current rate could offset some of the progress made under the Montreal Protocol and may have additional climate impacts.