Article 76 of unclos is remarkable in that it represents a spectacular nexus of legal and scientific concepts. Through the blending of legal and scientific terminology, the 618 words of Article 76 outline the methods by which a coastal State can establish the limits of its juridical continental shelf and, within these limits, exercise sovereign rights over the resources of the seafloor and subsurface. The importance of Article 76 was manifested by the long and often difficult negotiations that led to its final acceptance. In the best spirit of negotiation, these discussions led to many compromises, but at the same time they also led to ambiguities and the use of terminology that sometimes lacks clarity or precise definition. In addition to terminology that may have been left ambiguous, Article 76 sometimes uses scientific terminology in a legal sense that differs from its scientific definition or meaning. Just as importantly, it must be remembered that the scientific concepts captured in the Convention represent the state of knowledge at the time the Convention was being negotiated (1973–1982). At that time, our understanding of the nature of the seafloor (including its shape—i.e. bathymetry), and seafloor and ocean processes was very limited. The overarching paradigm of plate tectonics, explaining the origin and evolution of continents and oceans, was just being developed and the technology for mapping the seafloor was limited to simple single-beam echo sounders that produced sparse individual depth measurements and maps that missed many deep-sea features and were broadly smoothed representations of the actual seafloor.
The Commission on the Limits of the Continental Shelf (clcs) was created by the Convention to make recommendations to coastal States on matters related to the establishment of the outer limits of their continental shelf, and in 1999 the clcs generated Scientific and Technical Guidelines for the purpose of providing direction to coastal States and offering its interpretation of the terminology used in Article 76. Even since 1999, however, our ability to map the seafloor and our understanding of seafloor morphology and processes have changed significantly. Despite this greatly increased level of understanding of the seafloor and its processes, we must also remember that there is still great uncertainty in our understanding of seafloor processes leading to continued debate on, and multiple interpretations of the nature of seafloor features. Each of these issues presents challenges to the coastal States and the clcs.
This paper will briefly review Article 76, highlighting the scientific terminology that is presented (sometimes in a legal context) and outlining (in graphic form) the approach presented in Article 76 for establishing the limits of the continental shelf. While the list of terminology is long, the greatest effort on the part of both the coastal State and the clcs has typically focused on determining the base of the slope zone (in order to locate the ‘foot of the slope’) and distinguishing between submarine ridges and submarine elevations that are natural components of the continental margin. The evolution of mapping technology will be reviewed to demonstrate how our current ability to map the seafloor has changed our perspective of both seafloor morphology and seafloor processes. This increased level of knowledge potentially adds further complexity to the interpretation of the Convention as the reality of today’s detailed mapping and geophysical measurements may conflict with the more basic understanding of continental margin morphology available to the drafters of the Convention. It is within this context that the clcs must execute its mandate, and in doing so, hopefully provide consistent and transparent guidance that establishes a basis for interpretation of Article 76 that is fully consistent with the Convention.