Amplified Interhemispheric Rainfall Contrast in Boreal Summer Due To Reduction in Anthropogenic Emissions Under COVID‐MIP Green Economic‐Recovery Scenarios

Our study looks at the precipitation responses to two possible future emission-mitigation pathways, pushed by the Coronavirus Disease 2019 pandemic (COVID-19) and achieving carbon neutrality in the mid-21st century. We find that a simultaneous-reduction in well-mixed greenhouse gases (WMGHGs) and anthropogenic aerosol emissions results in an enhanced interhemispheric precipitation contrast in the 2040s by amplifying the interhemispheric thermal contrast and strengthening the meridional overturning circulation in the tropics. Reduced aerosol emissions induce generally-increased precipitation in the Northern Hemisphere (NH) and an amplified intertropical rainfall contrast, while reduced WMGHG emissions dominate decrease in precipitation in the areas away from aerosol emission sources. Further, the above precipitation contrast will be enhanced under stronger emission-mitigation pathways, mainly attributed to larger precipitation increases in the NH caused by reduced aerosols. More aggressive WMGHGs mitigation policies are necessary to counteract the aerosol-induced warming in the NH, thereby mitigating the risk of regional drying or wetting due to the asymmetry in interhemispheric energy budgets.