Projected Changes to Arctic Sea-Ice and Commercial Shipping Routes due to Stratospheric Aerosol Injection

Climate intervention strategies like Stratospheric Aerosol Injection (SAI) could possibly be used to stabilize or reduce global temperatures. Impacts of SAI on Arctic sea-ice are largely unknown. We assess the future Arctic environment using CESM2 in the ARISE-SAI-1.5 and SSP2-4.5 scenarios, or projected future worlds with and without SAI, and determine the accessibility of Arctic shipping routes. Arctic routes have shorter transit times compared to lower latitude routes, and their accessibility is affected by ice conditions. The Transpolar Route is of particular interest as it is the shortest Arctic shipping route.

Across the entire Arctic Ocean, we find ice-free days arriving earlier over the years in SSP2-4.5, but the timing of ice-free days remains mostly stable in ARISE-SAI-1.5. Using Ice Numeral as a measure of safe navigability of a region, we count the number of safely navigable days in both scenarios for the shipping season of May-October for two types of ships – Polar Class 6 and Open Water vessels. SSP2-4.5 sees generally increasing navigability over the years while interestingly, Transpolar Route navigability decreases in ARISE-SAI-1.5. This is likely due to more multi-year ice surviving the melt season under SAI. This research can be furthered to find safest shipping schedules and applied to other potential SAI scenarios.