Linking Solar Geoengineering and Emissions Reductions : Strategically Resolving an International Climate Change Policy Dilemma

Solar geoengineering appears able to reduce climate-change risks but raises controversy, the leading cause of which is the concern that its research, development, or use might inappropriately obstruct efforts to cut greenhouse-gas emissions (“mitigation”). Describing how policies could effectively and feasibly manage such possible mitigation obstruction has proven elusive. An option would be to strategically link the international policies of mitigation and solar geoengineering. Here we explore this by disaggregating states based on their relevant characteristics: willingness to increase their own mitigation and to offer concessions to increase it elsewhere, willingness to implement solar geoengineering contrary to any international consensus, and desired magnitude of solar geoengineering. We propose linkages of mitigation policy with (1) solar geoengineering research and development, (2) decision-making regarding whether to deploy; and (3) that regarding how to deploy. Based on the incentives that states would face under them, these linkages are assessed on whether they can be expected to effectively increase mitigation and seem minimally feasible. Linkages in each of the three categories have potential and could occur sequentially. In that with the greatest apparent potential, one or more states would proclaim their right to deploy solar geoengineering if and only if they meet their own mitigation goals and the rest of the world insufficiently mitigates, and promise to forego this if either condition is not met. We identify possible challenges, including legitimacy, credibility, optimal size, relations among targets of the linkage, and stringency of mitigation goals. None of these are necessarily prohibitive