New technologies, such as social media and do-it-yourself biotechnology, alter the capacities and incentives of both state and nonstate actors. This can include enabling direct decentralized interventions, in turn altering actors’ power relations. The provision of global public goods, widely regarded as states’ domain, so far has eluded such powerful technological disruptions. We here introduce the idea of highly decentralized solar geoengineering, plausibly done in form of small high-altitude balloons. While solar geoengineering has the potential to greatly reduce climate change, it has generally been conceived as centralized and state deployed. Potential highly decentralized deployment moves the activity from the already contested arena of state action to that of environmentally motivated nongovernmental organizations and individuals, which could disrupt international relations and pose novel challenges for technology and environmental policy. We explore its feasibility, political implications, and governance.