EGU21-3162, updated on 11 Jan 2022
https://doi.org/10.5194/egusphere-egu21-3162
EGU General Assembly 2021
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Significant climate benefits from near-term climate forcer mitigation in spite of aerosol reductions

Robert Allen1, Larry Horowitz2, Vaishali Naik2, Naga Oshima3, Fiona O'Connor4, Steven Turnock4, Sungbo Shim5, Philippe Le Sager6, Twan van Noije6, Kostas Tsigaridis7, Susanne Bauer7, Lori Sentman2, Jasmin John2, Conor Broderick2,8, Makoto Deushi3, Gerd Folberth4, Shinichiro Fujimori9,10,11, and William Collins12
Robert Allen et al.
  • 1UC Riverside, Earth Sciences, Riverside, United States of America (rjallen@ucr.edu)
  • 2DOC/NOAA/OAR/Geophysical Fluid Dynamics Laboratory. Biogeochemistry, Atmospheric Chemistry, and Ecology Division, Princeton, USA
  • 3Meteorological Research Institute, Japan Meteorological Agency, Tsukuba, Ibaraki, Japan
  • 4Met Office Hadley Centre, Exeter, UK
  • 5National Institute of Meteorological Sciences, Seogwipo-si, Jeju-do, South Korea
  • 6Royal Netherlands Meteorological Institute (KNMI), De Bilt, Netherlands
  • 7Center for Climate Systems Research, Columbia University, NASA Goddard Institute for Space Studies, New York, NY, USA
  • 8Macalester College, St. Paul, MN, USA
  • 9Department of Environmental Engineering, Kyoto University, C1-3 361, Kyotodaigaku Katsura, Nishikyoku, Kyoto, Japan
  • 10Center for Social and Environmental Systems Research, National Institute for Environmental Studies (NIES), 16-2 Onogawa, Tsukuba, Ibaraki, Japan
  • 11International Institute for Applied System Analysis (IIASA), Schlossplatz 1, Laxenburg, Austria
  • 12Department of Meteorology, University of Reading, Reading, UK

Near-term climate forcers (NTCFs), including aerosols and chemically reactive gases such as tropospheric ozone and methane, offer a potential way to mitigate climate change and improve air quality--so called "win-win" mitigation policies.   Prior studies support improved air quality under NTCF mitigation, but with conflicting climate impacts that range from a significant reduction in the rate of global warming to only a modest impact.  Here, we use state-of-the-art chemistry-climate model simulations conducted as part of the Aerosol and Chemistry Model Intercomparison Project (AerChemMIP) to quantify the 21st-century impact of NTCF reductions, using a realistic future emission scenario with a consistent air quality policy.  Non-methane NTCF (NMNTCF; aerosols and ozone precursors) mitigation improves air quality, but leads to significant increases in global mean precipitation of 1.3% by mid-century and 1.4% by end-of-the-century, and corresponding surface warming of 0.23 and 0.21 K.  NTCF (all-NTCF; including methane) mitigation further improves air quality, with larger reductions of up to 45% for ozone pollution, while offsetting half of the wetting by mid-century (0.7% increase) and all the wetting by end-of-the-century (non-significant 0.1% increase) and leading to surface cooling of -0.15 K by mid-century and -0.50 K by end-of-the-century.  This suggests that methane mitigation offsets warming induced from reductions in NMNTCFs, while also leading to net improvements in air quality.

How to cite: Allen, R., Horowitz, L., Naik, V., Oshima, N., O'Connor, F., Turnock, S., Shim, S., Le Sager, P., van Noije, T., Tsigaridis, K., Bauer, S., Sentman, L., John, J., Broderick, C., Deushi, M., Folberth, G., Fujimori, S., and Collins, W.: Significant climate benefits from near-term climate forcer mitigation in spite of aerosol reductions, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-3162, https://doi.org/10.5194/egusphere-egu21-3162, 2021.

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