Rapid and deep reductions in greenhouse gas emissions are necessary to limit the harm to people around the world expected due to climate change over the 21st Century (IPCC, 2022). However, increasing awareness of the failure of global climate policy to bring about the rate of change in the global economic system necessary to meet the 1.5°C global warming level (van de Ven et al., 2023; UN Environment Programme, 2022;Sognnaes et al., 2021) identified in the Paris Agreement (UNFCCC, 2015) has led some to consider the use of solar geoengineering-the deliberate cooling of the planet by reflecting away incoming sunlight-to reduce these harms (National Academies of Sciences, Engineering, and Medicine, 2021). Such consideration has been made more urgent by the large changes in the climate system already observed at 1.1°C of warming (Gulev et al., 2021), changes which are particularly stark in the polar regions (Pörtner et al., 2019). Recent work has demonstrated the significant risk that several cryospheric tipping elements in the Earth system, including abrupt boreal permafrost thaw, and collapse of the West Antarctic Ice Sheet, may become active at global temperatures below the Paris