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, and evaluation 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. One option would be to strategically link the international policies of mitigation and solar geoengineering. Here I explore this by disaggregating states based on their relevant characteristics. I propose linkages of mitigation policy with: (1) solar geoengineering research and development, (2) decision-making regarding whether to deploy solar geoengineering, and (3) how to deploy solar geoengineering. 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 are seem minimally feasible. Linkages in each of the three categories have potential and could occur sequentially. In the linkage which I believe has the greatest 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 would promise to forego deployment if either condition is not met. I identify this proposed linkage’s possible challenges, including legitimacy, credibility, optimal size, relations among targets of the linkage, stringency of mitigation goals, and potential counterproductivity. Limitations to this exploration and assessment include the speculative nature, the assumption that states’ preferences regarding mitigation and solar geoengineering are properly related, and the use of noncooperative linkage. Key policy insights Solar geoengineering could reduce the impacts of climate change but is controversial, in large part because of concerns that its research, development, or use might obstruct efforts to cut greenhouse gas emissions. I explore and assess whether linking international policies of greenhouse gas emissions reductions and solar geoengineering could feasibly and effectively increase emissions reductions. In the linkage that I believe has the greatest potential, one or more states would proclaim their right to deploy solar geoengineering if and only if they meet their emissions reductions goals and other countries do not.