Three Pathways to Nonuse Agreement(s) on Solar Geoengineering

Recent years have seen increasing calls by a few scientists, largely from the Global North, to explore “solar geoengineering,” a set of speculative technologies that would reflect parts of incoming sunlight back into space and, if deployed at planetary scale, have an average cooling effect. Numerous concerns about the development of such speculative technologies include the many ecological risks and uncertainties as well as unresolved questions of global governance and global justice. This essay starts with the premise that solar geoengineering at planetary scale is unlikely to be governable in a globally inclusive and just manner. Thus, the ethically sound approach is to pursue governance that leads to the nonuse of planetary solar geoengineering. Yet is such a prohibitory agreement feasible, in the face of possible opposition by a few powerful states and other interests? Drawing on social science research and a host of existing transnational and international governance arrangements, this essay offers three illustrative pathways through which a nonuse norm for solar geoengineering could emerge and become diffused and institutionalized in global politics: (1) civil society-led transnational approaches; (2) regionally led state and civil society hybrid approaches; and (3) like-minded or “Schengen-style” club initiatives led by states.