For a long time, the obligation to co-operate occupied an ambiguous position in international law. It appeared in diverse treaty regimes and institutional contexts, yet it was seldom recognised as an autonomous, self-standing obligation, i.e., as a general duty of customary nature, underpinning the various legal regimes, and as a genuine legal obligation in its own right. One…

On 21 May 2024, at the request of the Commission of Small Island States on Climate Change and International Law (COSIS), the International Tribunal for the Law of the Sea (ITLOS or Tribunal) delivered its long-awaited advisory opinion. While some scholars have welcomed the advisory opinion for its ‘contextual and systemic approach to interpretation’ [cf. Paine],…

Since 2003, the United States (US) has been collecting, processing, and analyzing marine geophysical data to determine the outer limits of its continental shelf. Some 20 years later, on 19 December 2023, the US Department of State published the geographical coordinates that define its extended continental shelf (ECS), stating that: ‘The United States…