Do ozone depleting gases and their substitutes have an effect on climate”?
Stratospheric ozone depletion has an influence on climate change since both ozone and the compounds responsible for its depletion are active greenhouse gases.
Ozone depleting substances (ODSs) such as the CFCs have contributed to increases in global average surface temperature. On the other hand, ozone depletion itself has a cooling effect. Warming due to ODSs and cooling associated with ozone depletion are two distinct climate forcing mechanisms that do not simply offset one another. Bromine-containing gases currently contribute much less to warming than to cooling, whereas CFCs and HCFCs contribute more to warming than to cooling. HFCs and PFCs contribute only to warming.
Actions taken under the Montreal Protocol have led to the replacement of CFCs with HCFCs, HFCs, and other substances. Because replacement species (with the exception of HFCs) generally have lower global warming potentials (GWPs) and because total halocarbon emissions have decreased, their contribution to climate change has been reduced (Figure 12a). Ammonia and hydrocarbons used as halocarbon substitutes will have a negligible effect on global climate. The relative future warming and cooling effects of emissions of CFCs, HCFCs, HFCs, PFCs and halons vary. The indirect cooling effect of ODSs is projected to cease upon ozone layer recovery, so that GWPs associated with the indirect cooling effect depend on the year of emission, compliance with the Montreal Protocol and gas lifetimes.
Substitution for ODSs in air conditioning, refrigeration, and foam blowing by HFCs, PFCs, and other gases such as hydrocarbons are not expected to have a significant effect on global tropospheric chemistry.
Stratospheric ozone depletion has an influence on climate change since both ozone and the compounds responsible for its depletion are active greenhouse gases.
Ozone depleting substances (ODSs) such as the CFCs have contributed to increases in global average surface temperature. On the other hand, ozone depletion itself has a cooling effect. Warming due to ODSs and cooling associated with ozone depletion are two distinct climate forcing mechanisms that do not simply offset one another. Bromine-containing gases currently contribute much less to warming than to cooling, whereas CFCs and HCFCs contribute more to warming than to cooling. HFCs and PFCs contribute only to warming.
Actions taken under the Montreal Protocol have led to the replacement of CFCs with HCFCs, HFCs, and other substances. Because replacement species (with the exception of HFCs) generally have lower global warming potentials (GWPs) and because total halocarbon emissions have decreased, their contribution to climate change has been reduced (Figure 12a). Ammonia and hydrocarbons used as halocarbon substitutes will have a negligible effect on global climate. The relative future warming and cooling effects of emissions of CFCs, HCFCs, HFCs, PFCs and halons vary. The indirect cooling effect of ODSs is projected to cease upon ozone layer recovery, so that GWPs associated with the indirect cooling effect depend on the year of emission, compliance with the Montreal Protocol and gas lifetimes.
Substitution for ODSs in air conditioning, refrigeration, and foam blowing by HFCs, PFCs, and other gases such as hydrocarbons are not expected to have a significant effect on global tropospheric chemistry.
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