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