Nicaragua v Columbia: the curious question of the Commission on the Limits of the Continental Shelf

Continental shelf questions have a reputation for being arcane and technical, but an interesting point with implications for offshore resource disputes arose in last month’s ICJ judgement in Territorial and Maritime Dispute (Nicaragua v. Colombia).

First, a certain amount of (potentially dull) technical background needs to be set out, which I’ll simplify as much as possible.

Notably, Nicaragua is a party to the UN Convention on the Law of the Sea (UNCLOS) and Colombia is not. UNCLOS in Article 76(1) states a general principle:

The continental shelf of a coastal State comprises the seabed and subsoil of the submarine areas that extend beyond its territorial sea throughout the natural prolongation of its land territory to the outer edge of the continental margin, or to [an automatic] distance of 200 nautical miles from [its] baselines.

This 200 nm or “the outer edge of the continental margin” general definition of the limits of the continental shelf was always likely to be found to be customary international law – and now the ICJ has determined that it is (para 118: correct me if I’ve missed an earlier case).

The fiddly bit is, of course, determining where “the outer edge of the continental margin” is. The rest of Art. 76 UNCLOS sets out a mixed legal/geological definition of the continental shelf and subjects it two further constraints (i.e. you might not be able to legally claim your entire physical continental shelf if it is very broad). Under Art. 76(8) there is an obligation upon UNCLOS parties to submit information about the limits of their continental shelf beyond 200 nm to the Commission on the Limits of the Continental Shelf (CLCS) which:

shall make recommendations to coastal States on matters related to the establishment of the outer limits of their continental shelf. The limits of the shelf established by a coastal State on the basis of these recommendations shall be final and binding.

So, a State party to UNCLOS which asserts it has a continental shelf beyond 200 nm (and which wants “final and binding” outer continental shelf limits) must make a submission to the CLCS. Note that the CLCS is not a delimitation or dispute settlement body: it evaluates scientific evidence and makes “recommendations”. Further, CLCS processes are “without prejudice to” delimitation disputes between States: Art. 76(10), UNCLOS and Art. 9, Annexe II, UNCLOS.

Despite this the CLCS has (mis)interpreted its own mandate and has a practice of making no recommendations in specific areas subject to a dispute. (This despite the fact that it could simply claim to be determining the limits of the legally claimable shelf as a precursor to parties being able to discuss who owns what bits of it.) This gives a power of veto to disputant States and can result in the CLCS making no determination on areas within a claim.

Now, why is all this important? Because the ICJ said in Nicaragua v. Colombia (para 126):

In …Nicaragua v. Honduras … , the Court stated that “any claim of continental shelf rights beyond 200 miles [by a State party to UNCLOS] must be in accordance with Article 76 of UNCLOS and reviewed by the Commission on the Limits of the Continental Shelf” … The Court recalls that UNCLOS, according to its Preamble, is intended to establish “a legal order for the seas and oceans which will facilitate international communication, and will promote the peaceful uses of the seas and oceans, the equitable and efficient utilization of their resources”. The Preamble also stresses that “the problems of ocean space are closely interrelated and need to be considered as a whole”. Given the object and purpose of UNCLOS, as stipulated in its Preamble, the fact that Colombia is not a party thereto does not relieve Nicaragua of its obligations under Article 76 of that Convention.

Now this is odd for a number of reasons. First, Nicaragua v. Honduras involved two UNCLOS parties and involved no detailed discussion of Art. 76. Its relevance to a dispute involving an UNCLOS and non-UNCLOS party seems dubious.

Second, by quoting Nicaragua v. Honduras, the ICJ seems to suggest that even in a dispute with a non-UNCLOS party, UNCLOS parties must go through the Art. 76 process before the ICJ will delimit a shelf. This means some disputes risk becoming a stalemate (the ICJ will note hear a dispute until the CLCS has discharged its function; the CLCS will not do that until disputes are resolved). This also – superficially – seems to put the ICJ at odds with the International Tribunal for the Law of the Sea in the Bay of Bengal Case, in which ITLOS did not wait for CLCS recommendations before ruling on a continental shelf delimitation.

Third, the ICJ’s invokes the UNCLOS preamble in a manner suggesting UNCLOS has some wider public order implications, e.g. for the relationship between the ICJ and UNCLOS institutions like the CLCS.

The line of reasoning here is all the more puzzling given that it was unnecessary in order to decide the case. In para 127 the ICJ notes that Nicaragua had not made full technical submissions to the CLCS, but had only submitted “preliminary information”. A number of the dissenting opinions note that there was simply too little factual evidence to support findings about a continental shelf. (In addition, Nicaragua was trying to claim a continental shelf to advance a doomed argument I discuss below.) It would have seemed more sensible to dismiss the claim on factual grounds rather than on procedural grounds and with language that may create exaggerated expectations about UNCLOS as a quasi-constitutional order.

Two last points to note. First, any conflict between the ICJ in Nicaragua v. Colombia and ITLOS in Bay of Bengal is likely more apparent than real. In Bay of Bengal the technical information: (a) was much better (it had reached the level of full CLCS submissions); (b) was accepted by both parties; and (c) ITLOS did not actually effect a full delimitation of the outer continental shelf, it simply indicated the boundary beyond 200 nm only with an arrow. The two cases are thus distinguishable.

Second, Nicaragua was trying to advance an argument that was, to my mind, doomed. Essentially it wished to argue that in certain areas its geological continental shelf reached within Columbia’s 200 nm legally presumed shelf. In the case of such overlapping claims it suggested a median line should be drawn. This would obviously have the result of paring back or cutting into the 200 nm legally presumed shelf to give partial effect to the geological shelf. I don’t think any arbitral tribunal has ever directly ruled on the point, but no argument that a ‘physical shelf’ should be able to trump or detract from a ‘legal’ minimum shelf has ever succeeded (so far as I am aware). The ICJ found it unnecessary to rule on the argument given its other holdings.