#ozone #Montreal Protocol #climate change #SDGs #sustainable development
Stratospheric ozone layer protects life on Earth from damaging UV radiation, but cannot protect itself from depletion by certain chemicals. The Montreal Protocol therefore was established to protect the stratospheric ozone layer by enabling reductions in the abundance of ozone-depleting substances such as chlorofluorocarbons (CFCs) in the atmosphere.
One chemical of this group, Trichlorofluoromethane (CFC-11), contributes one-quarter of all chlorine reaching the stratosphere and its reduction in the atmospheric concentration has made the second-largest contribution to the decline in the total atmospheric concentration of ozone-depleting chlorine since the 1990s. The rate of decline of atmospheric CFC-11 concentrations observed at remote measurement sites was constant from 2002 to 2012, but worryingly slowed by about 50% after 2012.
With data and model analysis, a new publication on Nature suggest that there's increase in emission of CFC-11 despite reported production being close to zero since 2006. It appears related to unreported new production, although global CFC production has been banned by 2010 by the Montreal Protocol.
Please refer to the Nature publication for more intelligence.
(Montzka et.al. (2018) An unexpected and persistent increase in global emissions of ozone-depleting CFC-11. Nature (557), 413-417)