Recent international jurisprudence reveals a tendency to constrain the continental shelf beyond 200 nautical miles (NM) in two principal respects. First, in relation to entitlement, courts have progressively limited the role of natural prolongation, treating it as subordinate to, or loosely applying it alongside, the distance criterion. This interpretation narrows the conditions under which a State may establish rights beyond 200 NM, thereby constraining the substantive scope of entitlement envisaged by Article 76 of the United Nations Convention on the Law of the Sea (UNCLOS) and the practice of the Commission on the Limits of the Continental Shelf. Second, regarding delimitation, judicial bodies have relied on the notion of a single continental shelf to extend the same equitable boundary line used within 200 NM seaward, effectively subordinating the outer shelf to the inner shelf. These developments restrict both the legal and spatial reach of outer continental shelf claims, reshaping the interpretation of the continental shelf beyond 200 NM in ways that appear increasingly difficult to reconcile with the natural prolongation-based framework established under Article 76 UNCLOS.

En mai 2019, le Canada a présenté sa soumission concernant son plateau continental étendu arctique à la Commission des limites du plateau continental. La délinéation des plateaux continentaux étendus, conformément à la Convention des Nations Unies sur le droit de la mer, résulte d’interprétations dans lesquelles s’entrelacent arguments scientifiques et juridiques à l’égard d’une situation géophysique singulière. Cet article examine la manière dont le Canada a composé avec la triple interprétation juridique, scientifique et factuelle à travers une étude articulée autour de la notion de “prolongement naturel.” Sont mis en relief les défis interprétatifs, mais aussi les opportunités que le Canada a saisies en participant au dégagement de consensus scientifiques et juridiques au soutien de la délinéation qu’il propose.

The delimitation of maritime boundaries is a complex and multifaceted process with legal and technical aspects. The process involves the determination of a maritime boundary in a situation where two or more states are confronted with overlapping titles. In the absence of any precise rules in treaty law and established customary rules based on state practice, it has been left to the jurisprudence of international courts and tribunals to develop the applicable law of maritime boundary delimitation. This article provides a detailed examination of the complex and multifaceted processes involved in maritime delimitation law. In doing so, it highlights recent developments in the field, with an emphasis on the emerging principles of “non-cut-off” and “non-distortion.” The article also analyzes the crystalizing rules on delimitation beyond 200 nautical miles and questions the applicability of these rules to the ongoing maritime boundary dispute between Canada and the United States in the Beaufort Sea.