Coupling between the stratosphere and the troposphere allows changes instratospheric ozone abundances to affect tropospheric chemistry. Large-scaleeffects from such changes on chemically produced tropospheric aerosols havenot been systematically examined in past studies. We use acomposition-climate model to investigate potential past and future impactsof changes in stratospheric ozone depleting substances (ODS) on troposphericoxidants and sulfate aerosols. In most experiments, we find significantresponses in tropospheric photolysis and oxidants, with small butsignificant effects on methane radiative forcing. The response of sulfateaerosols is sizeable when examining the effect of increasing future nitrousoxide (NO) emissions. We also find that without the regulation ofchlorofluorocarbons (CFCs) through the Montreal Protocol, sulfate aerosolscould have increased by 2050 by a comparable amount to the decreasespredicted due to relatively stringent sulfur emissions controls. Theindividual historical radiative forcings of CFCs and NO through theirindirect effects on methane (−22.6 mW m for CFCs and −6.7 mW mfor NO) and sulfate aerosols (−3.0 mW mfor CFCs and +6.5 mW m for NO when considering the direct aerosol effect)discussed here are non-negligible when compared to known historical ODSforcing. Our results stress the importance of accounting forstratosphere-troposphere, gas-aerosol and composition-climate interactionswhen investigating the effects of changing emissions on atmosphericcomposition and climate.
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