A113-0012
Reappraisal of the Climate Impacts of Ozone-Depleting Substances

Friday, 11 December 2020
Poster
Olaf Morgenstern1, Fiona M O'Connor2, Ben Thomas Johnson3, Guang Zeng4, Jane Patricia Mulcahy5, Jonny Williams1, Joao Teixeira2, Martine Michou6, Pierre Nabat7, Larry Wayne Horowitz8, Vaishali Naik8, Lori Thompson Sentman9, Makoto Deushi10, Susanne Bauer11, Kostas Tsigaridis12, Drew T Shindell13 and Douglas Edward Kinnison14, (1)National Institute of Water and Atmospheric Research (NIWA), Wellington, New Zealand, (2)UK Met Office, Exeter, United Kingdom, (3)Met Office, Exeter, United Kingdom, (4)National Institute of Water and Atmospheric Research, Wellington, New Zealand, (5)Met Office Hadley Centre for Climate Change, Exeter, United Kingdom, (6)Météo-France Toulouse, Toulouse Cedex 01, France, (7)METEO FRANCE/CNRM, Toulouse, France, (8)NOAA GFDL, Princeton, NJ, United States, (9)Geophysical Fluid Dynamics Lab, Princeton, NJ, United States, (10)Meteorological Research Inst., Tsukuba, Japan, (11)NASA Goddard Institute for Space Studies, New York, United States, (12)Columbia University, New York, NY, United States, (13)Duke University, Durham, NC, United States, (14)NCAR, Boulder, CO, United States
Abstract:
We assess the effective radiative forcing due to ozone-depleting substances using models participating in the Aerosols and Chemistry and Radiative Forcing Model Intercomparison Projects (AerChemMIP, RFMIP). A large inter-model spread in this globally averaged quantity necessitates an emergent constraint approach whereby we link the radiative forcing to the amount of ozone depletion measured and simulated during 1979-2000, excluding two volcanically perturbed periods. During this period ozone-depleting substances were increasing, and several merged satellite-based climatologies document the ensuing decline of total-column ozone. We use these analyses to come up with effective radiative forcing magnitudes. For an average of these satellite climatologies we find a best-estimate effective radiative forcing on the edge of the previously published "likely" range given by the 5th Assessment Report of IPCC, implying a likely offsetting effect of ozone depletion and/or other atmospheric feedbacks of -0.39 to -0.21 Wm-2, which in absolute terms is larger than the previous best estimate of -0.15 (-0.3 to 0) Wm-2, but is consistent with other literature results.
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