A dual-principle framework for the Area’s environmental compensation fund: pairing the Polluter Pays Principle with shared responsibility

Deep-sea mining (DSM) presents environmental risks characterized by scientific uncertainty and potential transboundary harm. Current regulatory frameworks governing the Environmental Compensation Fund (ECF) rely solely on the Polluter Pays Principle (PPP), which is inadequate to tackle challenges inherent in the status of the International Seabed Area (the Area) as the common heritage of mankind (CHM), particularly when the environmental damage involves indivisible causation among multiple actors. This article analyzes the doctrinal development and practice of shared responsibility in international law, surveying precedents in oil pollution, nuclear, and hazardous-substance regimes, and evaluates its alignment with the CHM and applicability to the DSM regime. Findings reveal that shared responsibility addresses limitations of the single-actor PPP through structural congruence with the CHM, correspondence with seabed risks, and institutional utility. It proposes a dual-principle ECF framework integrating shared responsibility as a necessary complement to the PPP. This integrated approach aims to mitigate systemic risks and helps to bridge residual gaps and strengthen environmental protection in the Area.