Ozone layer recovery could face setbacks

Abstract

Earlier this year, the United Nations announced that the stratospheric ozone layer is on track to recover within 4 decades thanks to the Montreal Protocol , which guided the phaseout of ozone-depleting compounds, such as chlorofluorocarbons (CFCs). But sources of CFCs and other chemicals not covered by the international agreement could extend this recovery timeline. A new study has found that atmospheric concentrations of five CFCs have been increasing since 2010 despite bans on their use and production ( Nat. Geosci. 2023, DOI: 10.1038/s41561-023-01147-w ). The researchers think they could be released during the production of other chemicals, such as hydrofluorocarbons (HFCs), which are more ozone-friendly refrigerants. The Montreal Protocol does not ban the use of CFCs as chemical feedstocks. Aside from CFCs, other compounds, such as bromoform, can contribute to ozone depletion, says Susann Tegtmeier, an atmospheric scientist at the University of Saskatchewan. Bromoform is not regulated by the