A scenario of solar geoengineering governance: Vulnerable states demand, and act

•In this scenario, states vulnerable to impacts of climate change deploy solar geoengineering; the article provides insights into possible responses of a Great Power Bloc (Member of UN Security Council + Japan and Germany).•We investigate the differences of possible responses; esp. with regard to challenges linked to a “free-driver” dynamic.•Varying assumptions about international relations in 2040 substantially shape the responses by the different groups (between hegemonic & non-aligned approaches).•We explore prospects of multilateral governance of solar geoengineering and point to questions about the functioning and cohesion of alliances.