Leaks of CFCs threaten ozone layer recovery and climate

More ozone-depleting chemicals than previously thought are leaking out of old air conditioners and plastic foam, an international team of scientists reports (Nat. Commun. 2020, DOI: 10.1038/s41467-020-15162-7). The findings have implications for the recovery of Earth’s stratospheric ozone layer—which absorbs most ultraviolet radiation from the sun—and for climate change. The chemicals are chlorofluorocarbons (CFCs), which are known to deplete ozone and are potent greenhouse gases. They were formerly used as refrigerants and as blowing agents for foam. Production of CFC-11 and CFC-12 virtually ceased globally in 2010 in compliance with a global treaty, the Montreal Protocol on Substances That Deplete the Ozone Layer. But atmospheric measurements show that releases of these chemicals are continuing, according to a team of researchers led by Megan Lickley, a doctoral student in climate science at the Massachusetts Institute of Technology. Lickley and her colleagues took into account previous studies that identified unexpected emissions and