
3. Stratospheric Aerosol Injections
Sensitivity analysis of polar stratospheric aerosol injection strategies across three Earth system models
Walker Lee
Climate model experiments have shown that stratospheric aerosol injection (SAI) may reduce some high-latitude impacts of global warming, including sea ice loss, permafrost thaw, and ice sheet melt. High-latitude SAI offers several possible advantages over subtropical SAI, including reduced logistical barriers due to a lower deployment altitude, as well as focused cooling at the high latitudes to offset Arctic amplification. However, high-latitude SAI also offers additional challenges, such as increased dependence on seasonality of injection. Here, we present an intermodel comparison of simulations of high-latitude SAI from the Community Earth System Model (CESM), UK Earth System Model (UKESM), and Energy Exascale Earth System Model (E3SM). Our simulations consider injection at different latitudes and in different months of the year, in both hemispheres, to evaluate the optimal injection pattern across models. Additionally, we consider injection at different altitudes to evaluate the trade-off in efficiency between lower-altitude injections which may be possible with existing aircraft and higher-altitude injections which would require novel aircraft.