A new study has found that emissions of five ozone-depleting chemicals, whose production was banned for most uses under the Montreal Protocol, increased rapidly between 2010 and 2020. The emissions of these five chlorofluorocarbons (CFCs) are partly caused by leakage during the production of ozone-friendly substitutes. Although such emissions of by-products and intermediates are permitted under the Montreal Protocol, they are contrary to its objectives - and the observed increases are a cause for concern.
According to the researchers, the emissions of these CFCs do not currently pose a significant threat to the recovery of the ozone layer. However, due to the current increase, they could make a significant contribution to the total emissions of ozone-depleting chemicals in the future. As they are potent greenhouse gases, they also have an impact on the climate: in total, their emissions are equivalent to theCO2 emissions of a smaller country like Switzerland in 2020, which is about one percent of total greenhouse gas emissions in the US or 1/1000 of global greenhouse gas emissions. CFCs are chemicals that destroy the Earth's protective ozone layer. In the past, they were used extensively in the manufacture of hundreds of products, such as aerosol sprays, blowing agents for foams and packaging materials, and solvents and refrigerants. The production of CFCs for these purposes was banned in 2010 under the Montreal Protocol. The new study focused on five CFCs for which there are currently few known uses - CFC-13, CFC-112a, CFC-113a, CFC-114a and CFC-115 - and which have an atmospheric lifetime of 52 to 640 years. In terms of their impact on ozone, the emissions of these five CFCs are equivalent to about one tenth of the current emissions of CFC-11, one of the most controlled substances in this group.
