The challenge of global climate change has attracted recommendations for remediation from a number of professions, including engineering. The possibilities suggested for “geoengineering” the climate generally fall into one of two categories: (1) removing gaseous carbon dioxide from the air and storing it in long-term repositories (“carbon dioxide removal”); and (2) limiting or reducing the intensity of incoming electromagnetic waves from the sun (“solar radiation management”). Specific and often controversial proposals include the aerial dispersion of aerosols, launching reflective gratings into orbit around the Earth, and seeding the oceans with iron filings. These proposals share the following characteristics: (1) they can be undertaken within the territorial jurisdiction of a single state or in areas beyond national jurisdiction; (2) they are likely to, and are intended to, have extrajurisdictional—indeed, global— effects; and (3) they are largely unregulated at the international level. This Essay examines the existing international governance structures to address geoengineering and concludes that they are inadequate to the task. After reviewing those modest international measures that have been adopted to regulate climate geoengineering proposals, the Essay makes recommendations for structural adaptations in international governance to address the problem of climate change.