Montreal Space Symposium

Space geoengineering consists of intentionally deploying means to deviate the Sun’s heat in space. This technique has been identified as one among the few options that would allow the international community to ”buy precious time” against global warming (one of the most problematic consequences of climate change) by halting and reducing it. In fact, because geoengineering alone is not a solution to the various effects of climate change, this acquired time would allow the international community to discuss and agree on more effective and durable climate change mitigation measures. Of the many ways of deviating the Sun’s heat through space geoengineering, three have been identified as feasible. 1) Placing orbiting reflectors in the Earth’s orbit, which would however create significant orbital debris hazards. 2) Placing clouds of dust grains at the stable Earth-Moon triangular Lagrange points, solution which would nevertheless work for only a relatively short period each month, when those clouds would be between the Earth and the Sun. 3) Creating a station of some large (or many small) occulting discs close to the Sun-Earth Lagrange equilibrium point. This third method, which has been identified as the most effective and less risky, contemplates the possibility of fabricating parts of the station in-orbit by using outer space resources. The study explores which legal consequences arise, under current international space law from a possible space geoengineering deployment, especially if this would result from the unilateral decision of a country. Space geoengineering, in fact, will likely have climate effects affecting all countries, even if one single state decides to deploy it for its own benefit. Space law principles such as those of common interest, freedom and non-appropriation and other international law principles such as those of non-interference and cooperation are critically analyzed against such a usage of outer space. The study also provides a comparative analysis of the international space law provisions that seem to hinder such space application versus those which, on the contrary, could stimulate it. Last but not least, a critical assessment is made of the liabilities and responsibilities that states could encounter under international space law in the case of space geoengineering deployment. In its conclusion, the study explores whether the current corpus juris spatialis is suitable for future space geoengineering activities and what are the desirable changes it should eventually undertake.