Joint Responsibility between the EU and Member States for Non-Performance of Obligations Under Multilateral Environmental Agreements

This chapter explores the basis and manifestations of joint responsibility between the European Union (EU) and its Member States for non-performance of obligations contained in multilateral environmental agreements (MEAs). Joint responsibility has often been advanced as an attractive solution where two or more actors contribute to damage and it is unclear what part of the damage is caused by whom. Such proposals seem to be inspired by domestic law, where joint (or 'joint and several') liability is frequently used to solve liability questions involving multiple tortfeasors. However, the conditions, contents and consequences of joint responsibility in international law remain uncertain. One of the rare situations where the principle actually has found application concern cases of non-performance of obligations under MEAs by the EU and its Member States. The relevance of the principle in this context stems from the fact that while the EU and Member States have shared (external) competences in environmental law, for third States the allocation of competences between the EU and Member States can be unclear and it may be difficult or even outright impossible to identify who is responsible for what. Indeed, the ILC recognized in the Commentary on the Draft Articles on Responsibility of International Organizations that such mixed situations indeed may call for the application of the principle of joint responsibility, but left it undefined what this means. This paper examines the possible foundations and meanings of the principle in this context and explores the (limited) practice