Risky Business: Complex Risks of Solar Geoengineering

Solar geoengineering is a risky endeavor. It is important to understand these risks for prudent risk management of solar geoengineering, of specific methods such as stratospheric aerosol injection (SAI), and of broader climate risks. This chapter discusses a framework for holistic risk assessment of SAI’s global and complex risks. SAI’s direct ecological impacts and impacts across the world’s interconnected social, economic, and political systems are highly uncertain. The biggest risk comes from SAI’s interactions with other global catastrophes. A catastrophe that would knock out SAI may result in a rapid slingshot back to warming-known as “termination shock.” It is in these worst cases where SAI is most definitively worse than climate change. This highlights a key issue in understanding how SAI contributes to global risk. When worst case catastrophes do not happen, SAI may be a prudent response. But when such catastrophes do happen, SAI could worsen global risk. Also important to consider are how current actions could lead to these future risks. Current research can (not will) lead to an undesirable SAI deployment. Short-term knowledge and research governance play important role in managing and creating SAI risks.