Global Problem—Regional Solution? International Law Reflections on an EU CO2 Emissions Trading Scheme for Ships

International law questions linked to a potential future European Union 'emission trading scheme' for shipping are addressed. If such a scheme were to be introduced (which is not yet clear), and if it were designed to cover emissions that have occurred beyond the territorial waters of the Member States or even in other States' maritime zones (which, in that case, seems likely), it would evoke interesting questions of principle relating to the jurisdiction of States to impose requirements on foreign ships for matters which take place beyond their territory. Different approaches to the question are discussed, starting from the law of the sea, but also including a brief review of other potentially relevant branches of international law. It is concluded that international law does not necessarily prevent the establishment of such a scheme, but places a number of important limitations on its design.