Chapter 3: Update on Global Ozone: Past, Present, and Future
Earth and related Environmental sciences
WMO (World Meteorological Organization), Geneva, Switzerland
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This chapter deals with the evolution of global ozone outside of the polar regions. The increase of ozone-depleting substance (ODS) concentrations caused the large ozone decline observed from the early satellite era (circa 1980) to the mid-1990s. Since the late 1990s, concentrations of ODSs have been declining due to the successful implementation of the Montreal Protocol. Ozone concentrations show latitudinally dependent increases in the upper stratosphere for the 2000–2016 period; changes in other parts of the stratosphere are not yet statistically significant. A new suite of model simulations confirms previous results for the upper stratosphere that about half of the observed increase is associated with declining ODSs. Ozone column trends are likewise positive but not generally statistically significant. Their overall evolution is, however, compatible with the decline in equivalent effective stratospheric chlorine (EESC). Over the next decades, we expect increasing global mean stratospheric ozone columns, as ODSs continue to decline. Emissions of greenhouse gases (GHGs), especially carbon dioxide (CO2 ), methane (CH4 ), and nitrous oxide (N2O), will also affect the evolution of global stratospheric ozone, particularly in the second half of the 21st century, when ODS concentrations are expected to be low.
CitationBraesicke, P.; Neu, J.; Fioletov, V.; Godin-Beekmann, S.; Hubert, D.; Petropavlovskikh, I.; Shiotani, M.; Sinnhuber, B.-M. (2018). Chapter 3: Update on Global Ozone: Past, Present, and Future. , Scientific Assessment of Ozone Depletion: 2018, Global Ozone Research and Monitoring. Project–Report No. 58, S9-S128, WMO (World Meteorological Organization), Geneva, Switzerland,