Banned CFCs still increasing in atmosphere

The release of CFCs into the atmosphere is responsible for the depletion of the ozone layer.

Global emissions of the five CFCs weighted by their impact on ozone depletion (a) and the climate (b). | Photo Credit: WESTERN ET AL. (2023), NATURE GEOSCIENCE

Atmospheric concentrations of five banned ozone-depleting chemicals, known as chlorofluorocarbons (CFCs), have reached a record high, according to a recent study, whose results were published in Nature Geoscience in early April.

The release of CFCs into the atmosphere is responsible for the depletion of the ozone layer that prevents harmful ultraviolet radiation from reaching the earth. By restricting the production and release of CFCs, and other ozone-depleting chemicals, the 1987 Montreal Protocol succeeded in enabling the restoration of the ozone layer.

The recent increase in atmospheric concentrations of five CFCs is, therefore, surprising and of considerable concern.

The study conducted by a team of scientists from the UK, the US, Switzerland, Australia, and Germany and led by the University of Bristol and National Oceanic and Atmospheric Administration (NOAA), found that the rise was, in part, linked to the use of CFCs to make other ozone-friendly alternatives.

While the Montreal Protocol banned the production of CFCs, it allowed their creation during the production of other chemicals, including hydrofluorocarbons (HFCs), the second-generation replacements for CFCs.

“CFC emissions from more widespread uses that are now banned have dropped to such low levels that emissions of CFCs from previously minor sources are more on our radar and under scrutiny,” said lead author Luke Western of the University of Bristol and NOAA’s Global Monitoring Laboratory (GML). “The key takeaway is that the production process for some of the CFC-replacement chemicals may not be entirely ozone-friendly, even if the replacement chemicals themselves are.”

The study considered five CFCs with practically no known uses—CFC-13, CFC-112a, CFC-113a, CFC-114a, and CFC-115. Martin Vollmer, a co-author of the study, said: “There are concerns of increasing emissions of these CFCs given the production projections for some of these new-generation fluorocarbon products.”