Time to worry

An analysis shows that emissions of ozone-depleting chemical CFC-11 is rising again

ozone-depleting chemical,t rich loro flu oro methane or CFC-11, are on the rise again, shows an analysis by the US National Oceanic and Atmospheric Administration. Though CFC-11 was once widely used as foaming agents, its production was phased out by the Montreal Protocol in 2010. The study shows the rate of decline of atmospheric CFC-11 was constant from 2002 to 2012, and then slowed by about 50 per cent after 2012. The unexpected increase is likely due to "new, unreported production from an unidentified source in East Asia", it says. This will put at risk the ozone hole over the South Pole, which has shown signs of recovery.