Illegal CFC production may be slowing ozone layer recovery

Levels of a key ozone-depleting chlorofluorocarbon (CFC) in the atmosphere are not going down as fast as they should be, researchers in the US have shown.

Their results indicate that emissions of trichlorofluoromethane – known as CFC-11 – are increasing, suggesting it is still being produced and used despite a ban on manufacturing it after 2010. The researchers warn that continued production of the gas could delay recovery of the ozone layer. CFC-11 was originally used as a refrigerant but was banned in 1987 under the Montreal Protocol, the international agreement designed to protect the ozone layer.