Editor’s note: Daniel Owen is a barrister at Fenners Chambers in the UK. He specializes in public law relating to use of the oceans. His essay, below, focuses on the continental shelf beyond 200 nautical miles from the baseline: the “outer” continental shelf. The term continental shelf has both a legal meaning and a geological and/or geomorphological meaning. It is the legal sense that is considered here.

Owen provides the following disclaimer: “The material in this essay is a summary and necessarily involves simplification of a complex area of international law. It should not be relied upon or treated as a substitute for legal advice in relation to individual situations. Daniel Owen shall have no responsibility for any loss that may arise from reliance on any part of the material contained in this essay.” He holds the copyright to this essay.

By Daniel Owen

This essay is about the continental shelf regime in international law. After introducing the regime, the essay briefly focuses on its relevance to environmental protection of the so-called outer continental shelf, such as via designation and management of MPAs. Article and annex references in this essay are to the 1982 United Nations Convention on the Law of the Sea (UNCLOS – text available via www.un.org/Depts/los/index.htm).

The continental shelf starts at the seaward limit of the territorial sea, and comprises the seabed and subsoil (Art. 76 (1)). Unlike the exclusive economic zone (EEZ), the continental shelf has no water column element. The coastal State has sovereign rights for the purpose of exploring the shelf and exploiting the shelf’s “natural resources” (Art. 77 (1)). Such rights are exclusive (Art. 77 (2)). The natural resources of the shelf have economic importance – e.g., oil and gas. However, the shelf’s natural resources are not restricted to non-living resources; they also include living organisms belonging to so-called “sedentary species” (Art. 77 (4)). The UNCLOS definition of “sedentary species” creates scope for debate in fact and in law about what is, or is not, such a species.

Assuming no spatial constraints imposed by neighboring States, the outer limits of the continental shelf lie 200 nautical miles (nm) from the baseline (like the EEZ) or at the “outer edge of the continental margin” (Art. 76 (1)), whichever is farther offshore. The outer edge of the continental margin is determined by geological and geomorphological criteria (Art. 76 (4)). Relevant data are required to apply those criteria. However, the maximum outer limits are 350 nm from the baseline or 100 nm from the 2500-m submarine depth contour (Art. 76 (5)). The part of the continental shelf beyond 200 nm is referred to here as the outer continental shelf or, for brevity, the outer shelf. Whereas the shelf within 200 nm is overlain by the EEZ (if the coastal State has claimed an EEZ), the outer is overlain by the high seas. The rest of this essay focuses on the outer shelf specifically.

A coastal State party to UNCLOS cannot unilaterally fix the outer limits of an outer continental shelf. Instead, there is a multilateral process it has to go through, involving a body called the Commission on the Limits of the Continental Shelf, or CLCS (Art. 76 (8) and Annex II). In broad terms, step one involves the coastal State making a submission to the CLCS on the outer limits, and step two involves the CLCS making recommendations to the coastal State. In essence, the coastal State can then do one of two things. It can either accept the CLCS’s recommendations, and establish outer limits on the basis of them, whereupon those limits become final and binding. Or it can disagree with the recommendations and make a revised or new submission to the CLCS.

UNCLOS specifies that the deadline for making submissions to the CLCS is 10 years from the date of entry into force of UNCLOS for the coastal State in question (Annex II). In May 2001 and June 2008, the parties to UNCLOS adopted important decisions regarding that deadline. In practice, the CLCS has received 12 submissions so far (see www.un.org/Depts/los/clcs_new/clcs_home.htm), some of which are partial submissions and some of which are by more than one coastal State. For any given coastal State party to UNCLOS with an outer shelf, uncertainty about the outer limits of that shelf will remain until that State has completed the multilateral process and has adopted valid final and binding limits.

If a coastal State has an outer shelf, it has sovereign rights to explore that outer shelf and to exploit its natural resources. So, for example, it has the exclusive right to exploit “sedentary species” and non-living resources – e.g. gas hydrates – of the outer shelf. But, as a corollary, it also has the right to regulate such activities in order to protect the marine environment. Thus the continental shelf regime, in potentially bringing areas of seabed and subsoil beyond 200 nm within coastal State jurisdiction, creates opportunities for protection of that seabed and subsoil by the particular coastal State in question. In all this talk of rights, it should be added that certain duties regarding environmental protection on the continental shelf also exist (e.g., Arts. 194 (5) and 208).

The right of the coastal State to regulate certain activities on the outer shelf in order to protect the marine environment may, in principle, be applied to the management of any MPAs located there. If a coastal State were to designate one or more MPAs on its outer continental shelf, its right to regulate certain activities there could, in principle, be used to effect management of such sites. Of course, the extent to which activities could be managed would need to be consistent with the coastal State’s sovereign rights regarding the continental shelf. The extent of the management would also need to reflect the fact that the outer continental shelf is overlain by high seas.

The fact that the outer continental shelf is overlain by high seas potentially raises some complex issues. In particular, it raises the possibility of some interactions between the exercise of high seas freedoms in the waters overlying the outer shelf (e.g., bottom trawling for non-sedentary species, which may damage sedentary species) and a coastal State’s rights regarding its outer shelf (e.g., the exclusive right to exploit sedentary species there). Further discussion of these interactions and their possible outcomes can be found in a 2006 report by the author, available at www.ngo.grida.no/wwfneap/Projects/Reports/WWF_Owen_Jurisdiction.pdf (paragraphs 219-231).

For more information

Daniel Owen, Fenners Chambers, Cambridge, UK. E-mail: daniel.owen@fennerschambers.co.uk