Public Lecture

Solar radiation modification (SRM) poses important challenges for climate policy and risk governance. SRM would not just reverse climate change, but could pose further ancillary impacts (depending on the method of SRM, such as stratospheric aerosol injection (SAI), or a space-based sunshade (SBS)). We develop a multi-risk analysis of SRM, including both biophysical (environmental) and sociopolitical (strategic) risks. This multi-risk analysis helps identify, evaluate, and compare multiple risks more systemically; helps compare policy options, such as alternative types of SRM, greenhouse gas (GHG) mitigation, and climate adaptation; helps point to corresponding (or missing) mechanisms for governance, including international agreements; helps identify affected groups for participatory inclusion, overcoming disregard and omitted voice; and helps seek ‘risk-superior’ policies that would reduce multiple risks in concert. We examine governance frameworks – uncoordinated, coordinated and comprehensive – for regulating SRM. We suggest two key near-term mechanisms that can help build up from uncoordinated toward more coordinated or even comprehensive approaches, and that can find support from both SRM advocates and critics: an international scientific assessment of SRM, and a transparent international monitoring system for SRM.