Response of Tipping Elements to Different Strategies of Stratospheric Aerosol Injection

Abstract Stratospheric aerosol injection (SAI) has been proposed as a complementary option to mitigate anthropogenic climate change risks. Using Community Earth System Model ensemble simulations, we assess the response of climate metrics relevant to a set of climate tipping elements in SAI scenarios targeting different temperature stabilization goals and for implementation at different latitudes. We analyze responses of tipping element metrics in simulations of a multi‐objective SAI strategy that is designed to simultaneously stabilize global mean temperature (T0), interhemispheric temperature gradient (T1), and equator‐to‐pole temperature gradient (T2), as well as simulations of SAI strategies designed just to stabilize T0. We show that SAI strategies considered here would reduce the risks for many tipping elements, but may either increase or decrease the risk of Antarctic ice sheet collapse and Sahel greening, depending on the specifics of injection strategy. For the same 1.0°C temperature stabilization target, high‐latitude injection would reduce the risk of northern cryosphere‐related tipping elements more effectively, such as Greenland ice sheet, Barents winter sea ice, and boreal permafrost. Meanwhile, low‐latitude injection would be more effective in stabilizing low‐latitude biosphere‐related tipping elements such as Amazon rainforest and coral reefs. The multi‐objective SAI injection is more effective in reducing the risk of most high‐latitude tipping elements than low‐latitude injection, and is more effective in reducing the risk of most low‐latitude tipping elements than high‐latitude injection. Our study highlights the importance of careful consideration in the trade‐offs between tipping element risk reduction and temperature pattern optimization in response to SAI strategies.