Impacts of reductions in non-methane short-lived climate forcers on future climate extremes and the resulting population exposure risks in Asia
Non-methane short-lived climate forcers (SLCFs), including aerosols, ozone, and their precursors, are important climate forcings and primary air pollutants. Stringent SLCF emissions controls to mitigate air pollution have been implemented by various governments, which will substantially impact the future climate. We investigate the changes in future climate extremes and resulting population exposure risks in Asia during 2031–2050 in response to non-methane SLCF emissions reductions using multi-model ensemble (MME) simulations under two scenarios (SSP3-7.0 and SSP3-7.0-lowNTCF) with different air quality control measures from the Aerosol and Chemistry Model Intercomparison Project (AerChemMIP), which is endorsed by Coupled Model Intercomparison Project phase 6 (CMIP6). The MME results show that future reductions in non-methane SLCF emissions lead to an increase of 0.23 W m -2 in global annual mean effective radiative forcing, thereby magnifying the greenhouse gas (GHG)-induced global surface warming by 0.19 K during 2031–2050. The additional warming caused by the non-methane SLCF reductions increases the regional average temperature on the hottest days (TXx) by 0.3 K, the percentage of warm days (TX90p) by 4.8 %, the number of tropical nights (TR) by 1.7 days, the warm spell duration (WSDI) by 1.0 days, the number of heavy precipitation days (R10) by 1.3 days, the maximum consecutive 5-day precipitation (RX5day) by 0.8 mm, and the total wet-day precipitation (R95p) by 16.4 mm during 2031–2050. For temperature extremes, the largest regional increases of TXx, TX90p, and WSDI occur in northern India (NIN) and northern China (NC). Relatively large increases in TR are predicted in NC and the Sichuan Basin (SCB), reaching 5.1 days and 4.9 days, respectively. For precipitation extremes, the regional changes are greatest in southern China (SC), particularly southwestern China (SWC), where reductions of non-methane SLCF emissions increases R10 by 3.0 days, RX5day by 2.2 mm, and R95p by 39.5 mm. Moreover, the populations ...
