An approach to sulfate geoengineering with surface emissions of carbonyl sulfide

Abstract. Sulfate geoengineering (SG) methods based on lower stratospheric tropical injection of sulfur dioxide (SO2) have been widely discussed in recent years, focusing the direct and indirect effects they would climate system. Here a potential alternative method is discussed, where emissions are located at surface or troposphere form carbonyl sulfide (COS) gas. There two time-dependent chemistry–climate model experiments designed from years 2021 to 2055, assuming 40 Tg-Syr-1 artificial global flux COS, which geographically distributed following present-day anthropogenic COS (SG-COS-SRF) 6 upper (SG-COS-TTL). The budget species as both SG-COS strategies sulfate aerosol optical depth (???=0.080 2046–2055), effective radius (0.46 µm), SOx deposition (+8.9 % for SG-COS-SRF; +3.3 SG-COS-TTL), tropopause radiative forcing (RF; ?-1.5 W m?2 all-sky conditions experiments). Indirect ozone, methane water vapour also considered, along with contribution. According our results, resulting net RF ?1.3 m?2, SG-COS-SRF, ?1.5 SG-COS-TTL, it comparable corresponding ?1.7 obtained sustained 4 stratosphere SO2 (SG-SO2, able produce increase depth). Significant changes ozone response found respect SG-SO2 (?5 DU versus +1.4 globally). ultraviolet B (UVB) perturbation accounts ?4.3 annual average (versus ?2.4 case), springtime Antarctic decrease ?2.7 +5.8 experiment). Overall, we find that an may be feasible more latitudinally uniform without need deployment aircraft. However, assumption rate uptake by soils plants does not vary increasing concentrations will investigated future work, studies needed prolonged exposure higher values humans ecosystems.