Geoengineering—the deliberate, large-scale manipulation of the environment—is being increasingly considered as an emergency solution to curb global warming, as efforts to reduce greenhouse gas emissions have largely proved inadequate. This Note explores one form of proposed geoengineering: solar radiation management, which contemplates spraying reflective particles into the stratosphere to cause a global cooling effect. Geoengineering presents many challenges to regulators because of its potential to cause trans-boundary harm, its relative ease of enactment, and its unknown nature. Current international environmental treaties do not address geoengineering and would likely inadequately regulate it. But premature multilateral geoengineering regulations, if agreed to by states, would likely stifle geoengineering research. Instead, norms surrounding geoengineering must be developed by researchers at the forefront of the field before these new standards are codified into multinational treaties. This Note looks to international GMO trade and ocean dumping regulations for inspiration as to how future multinational geoengineering regulation could work. Principles and institutions from these regulations—including the polluter pays principle, a mandatory permit system, and research and monitoring systems—should be incorporated into future international geoengineering regulations once adequate norms surrounding the substantive research of geoengineering are established.