Injection-Latitude Dependence of Arctic Sea Ice Recovery in Stratospheric Aerosol Injection Simulations

Under multiple anthropogenic warming scenarios in CMIP6, Arctic sea ice is projected to undergo a rapid seasonal decline by the mid-21st century. Stratospheric Aerosol Injection (SAI) has been proposed as a potential intervention to mitigate Arctic warming, yet the sensitivity of Arctic sea-ice recovery to aerosol injection latitude, including its magnitude and governing processes, remains insufficiently quantified. Here, we investigate how SAI injection latitude influences Arctic sea ice recovery using simulations with CESM2-WACCM6, in which sulfate aerosols are injected at latitudes ranging from 45°S to 45°N under fixed injection rates.

Our results show that Arctic sea ice recovery exhibits a strong dependence on injection latitude, with injections closer to the North Pole producing a more rapid and robust recovery in both sea-ice extent and volume. This response is associated with coordinated changes in clear-sky and cloud radiative fluxes, as well as enhanced surface albedo, which together favor a surface energy balance conducive to ice growth. Notably, we find that Arctic sea ice recovery does not scale linearly with global mean surface temperature under SAI, highlighting the importance of injection latitude in shaping regional cryospheric responses.