The recovery of stratospheric ozone from past depletion is underway owing to the 1987 Montreal Protocol and its subsequent amendments, which have been effective in phasing out the production and consumption of the major ozone-depleting substances (ODSs). However, there is uncertainty about the future rate of recovery. This uncertainty relates partly to unexpected emissions of controlled anthropogenic ODSs such as CCl3F and slower-than-expected declines in atmospheric CCl4. A further uncertainty surrounds emissions of uncontrolled short-lived anthropogenic ODSs (such as CH2Cl2 and CHCl3), which observations show have been increasing in the atmosphere through 2017, as well as potential emission increases in natural ODSs (such as CH3Cl and CH3Br) induced by climate change, changes in atmospheric concentrations of greenhouse gases N2O and CH4, and stratospheric geoengineering. These challenges could delay the return of stratospheric ozone levels to historical values, (for example, the abundance in 1980), by up to decades, depending on the future evolution of the emissions and other influencing factors. To mitigate the threats to future ozone recovery, it is crucial to ensure that the Montreal Protocol and its amendments continue to be implemented effectively in order to have firm control on future levels of ODSs. This action needs to be supported by an expansion of the geographic coverage of atmospheric observations of ODSs, by enhancing the ability of source attribution modelling, and by improving understanding of the interactions between climate change and ozone recovery.
1.MIT, Ctr Global Change Sci, 77 Massachusetts Ave, Cambridge, MA 02139 USA 2.Univ Cambridge, Dept Chem, Cambridge, England 3.Natl Ctr Atmospher Sci, Cambridge, England 4.Univ Leeds, Sch Earth & Environm, Leeds, W Yorkshire, England 5.Univ Leeds, Natl Ctr Earth Observat, Leeds, W Yorkshire, England 6.NOAA, Chem Sci Div, Earth Syst Res Lab, Boulder, CO USA 7.Kyungpook Natl Univ, Dept Oceanog, Daegu, South Korea
Recommended Citation:
Fang, Xuekun,Pyle, John A.,Chipperfield, Martyn P.,et al. Challenges for the recovery of the ozone layer[J]. NATURE GEOSCIENCE,2019-01-01,12(8):592-596