This chapter analyses the establishment, content and implementation of international environmental liability of the sponsoring State. First, it argues for a differentiation between State liability ex delicto and State responsibility and suggests to employ the former notion. Second, it points out the non-practicability of an application of the full reparation principle (restituto in integrum) for environmental damage and that liability of sponsoring State should be taken together with that of the contractor. Third, it argues that invocation of liability of the sponsoring State for environmental damage by the ISA is preferable to that by States (parties). As to liability of the ISA, it focuses on questions of whether and, if so, in what situations member States are held liable for the ISA. Based on analysis of the 2011 ILC Articles on Responsibility of International Organization, 1995 IDI Resolution and 2004 ILA Resolution, it finds out that there is a ‘no liability of member states’ rule which however allows for exceptions. It also discusses invocation of liability of the ISA.

The allocation of liability for environmental harm in areas beyond national jurisdiction (ABNJ) is complicated by several factors relating to the nature of the activities undertaken and the nature of environmental harm itself. These include the range of actors involved in activities that may give rise to environmental harm, and features of cumulative environmental damage, arising over a course of time either out of a connected or unconnected set of activities involving multiple actors or from external natural causes. To address these issues, this chapter outlines legal approaches to causation and the challenges that complex causal pathways may present in ABNJ. It then discusses the general approach to allocating responsibility to states and international organizations under international law and national law, and the channeling of liability to operational entities which is the principal approach in sector-specific civil liability regimes. Finally, it explores the rules that structure the allocation of liability in relation to specific ABNJ regimes and activities.

This chapter recalls the distinction between responsibility and liability as it emerged in the work of the International Law Commission and its inherent difficulties, before turning to its relevance in relation to the interplay between the obligation to prevent harm and the prohibition to cause harm, the question of cessation and the procedural treatment at the International Court of Justice of the issues of injury, causality and reparation owed. The chapter questions the received wisdom according to which ‘responsibility’ and ‘liability’ would be two different legal genres and argues that the dichotomy between them is porous.