The Continental Shelf

The geological limb. A State whose margin extends beyond two hundred miles gets the whole margin, subject to the outer limits below.

Article 76(3). The continental margin comprises the submerged prolongation of the land mass of the coastal State, and consists of the seabed and subsoil of the shelf, the slope and the rise. It does not include the deep ocean floor with its oceanic ridges or its subsoil.

Article 76(4) gives two formulae for fixing the outer edge where the margin extends beyond two hundred miles: a line by reference to fixed points at each of which the thickness of sedimentary rocks is at least one per cent of the shortest distance from that point to the foot of the continental slope, or a line by reference to fixed points not more than sixty nautical miles from the foot of the slope. In the absence of evidence to the contrary the foot of the continental slope is the point of maximum change in the gradient at its base.

Article 76(5) caps them: the fixed points shall either not exceed 350 nautical miles from the baselines, or not exceed 100 nautical miles from the 2,500 metre isobath, which is a line connecting the depth of 2,500 metres.

Article 76(8) requires a State claiming beyond two hundred miles to submit information to the Commission on the Limits of the Continental Shelf, which makes recommendations, and limits established by the coastal State on the basis of those recommendations are final and binding.

The rights: article 77

Article 77(1). The coastal State exercises over the continental shelf sovereign rights for the purpose of exploring it and exploiting its natural resources.

Article 77(2). Those rights are exclusive in the sense that if the coastal State does not explore the shelf or exploit its natural resources, no one may undertake these activities without its express consent.

Article 77(3). The rights do not depend on occupation, effective or notional, or on any express proclamation. This is the provision behind the North Sea judgment's statement that the coastal State's rights exist ipso facto and ab initio, by virtue of its sovereignty over the land, and that no special legal acts have to be performed to exercise them.

Article 77(4). The natural resources consist of the mineral and other non-living resources of the seabed and subsoil, together with living organisms belonging to sedentary species, that is, organisms which at the harvestable stage either are immobile on or under the seabed or are unable to move except in constant physical contact with the seabed or subsoil. So oysters and corals are shelf resources; fish swimming above are not.

What the rights do not touch

Article 78(1). The rights of the coastal State over the shelf do not affect the legal status of the superjacent waters or of the air space above them. So the water above a State's shelf may be exclusive economic zone or high seas, and the shelf gives no rights over it.

Article 78(2). The exercise of shelf rights must not infringe or result in any unjustifiable interference with navigation and other rights and freedoms of other States.

Article 79. All States are entitled to lay submarine cables and pipelines on the continental shelf, subject to the coastal State's right to take reasonable measures for exploration, exploitation and the prevention of pollution from pipelines, and the delineation of the course for laying pipelines is subject to its consent.

Article 80 applies article 60, on artificial islands and installations, to the shelf. Article 81: the coastal State has the exclusive right to authorise and regulate drilling on the shelf for all purposes. Article 85: the Part does not prejudice the right to exploit the subsoil by tunnelling, irrespective of the depth of water above.

Payments for the outer shelf: article 82

A provision students overlook and examiners like.

Article 82(1). The coastal State shall make payments or contributions in kind in respect of the exploitation of the non-living resources of the continental shelf beyond 200 nautical miles.

The payments are made annually after the first five years of production at a site, rising from one per cent in the sixth year by one point a year to seven per cent in the twelfth and thereafter. A developing State which is a net importer of a mineral resource produced from its shelf is exempt in respect of that resource. The payments are made through the International Seabed Authority, which distributes them on the basis of equitable sharing criteria.

That article is the bridge between the shelf and the common heritage regime in [The Common Heritage of Mankind]: the outer shelf belongs to the coastal State and the international community takes a share of what comes out of it.

Article 84 requires the outer limit lines of the continental shelf and the lines of delimitation drawn under article 83 to be shown on charts of adequate scale or replaced by lists of geographical coordinates, with due publicity and deposit with the Secretary-General of the United Nations and, for lines of outer limits beyond two hundred miles, with the Secretary-General of the Authority.

Delimitation

Article 83(1). The delimitation of the continental shelf between States with opposite or adjacent coasts shall be effected by agreement on the basis of international law, as referred to in article 38 of the Statute of the International Court of Justice, in order to achieve an equitable solution.

That is the subject of [Delimitation of Maritime Boundaries], where the North Sea Continental Shelf cases and Continental Shelf (Tunisia/Libyan Arab Jamahiriya) are worked in full.

India's shelf

Section 6 of the Maritime Zones Act 1976. The continental shelf of India comprises the seabed and subsoil of the submarine areas that extend beyond the limit of its territorial waters throughout the natural prolongation of its land territory to the outer edge of the continental margin or to a distance of two hundred nautical miles from the baseline where the outer edge of the continental margin does not extend up to that distance.

The section vests in India full and exclusive sovereign rights in respect of the shelf for the purposes of exploration, exploitation, conservation and management of its resources, and provides for the Central Government to declare designated areas and to extend enactments to them.

A worked example

State EE has a coast from which the continental margin extends 260 nautical miles before dropping to the deep ocean floor. State FF, across a wide sea, has a margin stopping at 60 miles. Both find oil.

How far does State EE's shelf reach? To the outer edge of the margin at 260 miles, under the geological limb of article 76(1), provided it can establish the outer edge by one of the two article 76(4) formulae, the sediment thickness rule or the sixty-mile rule from the foot of the slope, and provided the fixed points respect the article 76(5) caps of 350 miles from the baselines or 100 miles from the 2,500 metre isobath. It must submit the information to the Commission on the Limits of the Continental Shelf under article 76(8).

How far does State FF's shelf reach? Two hundred miles, under the distance limb, notwithstanding that its margin stops at sixty. Geology cannot take away what distance gives.

Must either State proclaim its shelf? No. Article 77(3): the rights do not depend on occupation, effective or notional, or on any express proclamation, and the North Sea judgment describes them as existing ipso facto and ab initio.

A foreign company begins drilling on State FF's shelf at 150 miles without permission. Article 77(2) makes the rights exclusive in the sense that if the coastal State does not exploit, no one else may without its express consent, and article 81 gives it the exclusive right to authorise and regulate drilling for all purposes.

A foreign fleet fishes in the water column above the same spot. Article 78(1): shelf rights do not affect the legal status of the superjacent waters. Whether State FF can stop them depends on whether it has an exclusive economic zone, which is the next chapter, and on whether the species are sedentary, since article 77(4) puts sedentary species on the shelf side of the line.

State EE begins producing oil at 240 miles. Article 82 applies. After the first five years of production at that site it must make annual payments or contributions in kind through the International Seabed Authority, at one per cent of the value or volume of production in the sixth year, rising by one point a year to seven per cent in the twelfth and thereafter.

A third State wants to lay a cable across both shelves. Article 79(1) entitles all States to lay submarine cables and pipelines on the continental shelf, subject to the coastal State's reasonable measures and, for pipelines, to its consent as to the course.

Distinctions table

What it does NOT mean

The coastal State is not sovereign over the shelf. It has sovereign rights for exploring and exploiting, which is a defined bundle and not sovereignty.

Shelf rights give nothing in the water above. Article 78(1) is explicit.

Not all living things on the shelf are shelf resources. Only sedentary species within article 77(4).

The shelf does not have to be claimed, unlike the exclusive economic zone.

The margin is not the whole seabed. Article 76(3) excludes the deep ocean floor with its oceanic ridges and subsoil, which is the Area.

Limits and criticism

Article 76 is a geologist's provision in a lawyer's convention. The sediment thickness rule, the foot of the slope and the 2,500 metre isobath require survey data that many States cannot afford to collect, so the outer shelf is in practice claimable by those who can pay for the science.

The Commission recommends and does not decide boundaries. It cannot consider a submission where a land or maritime dispute exists unless the States concerned consent, so an unresolved dispute can leave a State's outer limit unsettled indefinitely.

Article 82 has never been applied in earnest. Production beyond two hundred miles is only now beginning, and how the Authority will collect and distribute the payments remains largely untested.

Quick revision

Article 76(1): seabed and subsoil beyond the territorial sea, throughout the natural prolongation to the outer edge of the continental margin, or to 200 nautical miles where the margin falls short. 76(3): the margin is shelf, slope and rise, and excludes the deep ocean floor. 76(4): the sediment-thickness rule of one per cent and the sixty-mile rule from the foot of the slope. 76(5): caps of 350 nm from the baselines or 100 nm from the 2,500 metre isobath. 76(8): the Commission on the Limits of the Continental Shelf.

Article 77: sovereign rights to explore and exploit; exclusive, so nobody else may act without express consent; do not depend on occupation or proclamation, hence ipso facto and ab initio; resources are minerals plus sedentary species.

Article 78: no effect on the superjacent waters or airspace, and no unjustifiable interference with navigation. 79: cables and pipelines by all States, pipeline routes needing consent. 81: exclusive right to authorise drilling. 82: payments beyond 200 nm through the Authority, 1 per cent in the sixth year rising to 7 per cent. 83: delimitation by agreement to achieve an equitable solution. 85: tunnelling.

India: section 6 of the Maritime Zones Act 1976, matching article 76 and vesting full and exclusive sovereign rights.

Test yourself

1. Define the continental shelf under article 76.

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 a distance of two hundred nautical miles from the baselines from which the breadth of the territorial sea is measured where the outer edge of the continental margin does not extend up to that distance. The margin consists of the shelf, the slope and the rise, and does not include the deep ocean floor with its oceanic ridges or its subsoil.

2. Must a State proclaim its continental shelf?

No. Article 77(3) provides that the rights of the coastal State over the continental shelf do not depend on occupation, effective or notional, or on any express proclamation. That is why the North Sea Continental Shelf cases describe those rights as existing ipso facto and ab initio, by virtue of the State's sovereignty over the land of which the shelf is the natural prolongation, and why the Court rejected the theory of apportioning shelf into just and equitable shares: the task is to delimit an area that already appertains, not to allot one.

3. How far may the shelf extend beyond two hundred miles?

Where the continental margin extends beyond two hundred miles, article 76(4) allows the outer edge to be fixed either by fixed points at each of which the thickness of sedimentary rocks is at least one per cent of the shortest distance from that point to the foot of the continental slope, or by fixed points not more than sixty nautical miles from the foot of the slope. Article 76(5) caps the result: the fixed points shall either not exceed 350 nautical miles from the baselines or not exceed 100 nautical miles from the 2,500 metre isobath. A State claiming beyond two hundred miles must submit information to the Commission on the Limits of the Continental Shelf under article 76(8), and limits established on the basis of its recommendations are final and binding.

4. What are the natural resources of the shelf?

Article 77(4) defines them as the mineral and other non-living resources of the seabed and subsoil, together with living organisms belonging to sedentary species, that is to say, organisms which at the harvestable stage either are immobile on or under the seabed or are unable to move except in constant physical contact with the seabed or the subsoil. So oysters, corals and similar species are shelf resources; fish in the water column are not, and rights over them depend on the exclusive economic zone regime instead.

5. Do a coastal State's shelf rights affect the waters above it?

No. Article 78(1) provides that the rights of the coastal State over the continental shelf do not affect the legal status of the superjacent waters or of the air space above those waters, and article 78(2) requires that the exercise of those rights must not infringe or result in unjustifiable interference with navigation and the other rights and freedoms of other States. Article 79 preserves the entitlement of all States to lay submarine cables and pipelines on the shelf, subject to the coastal State's reasonable measures and, for the course of pipelines, to its consent.

6. What is article 82 and why is it interesting?

It requires the coastal State to make payments or contributions in kind in respect of the exploitation of the non-living resources of the continental shelf beyond two hundred nautical miles, annually after the first five years of production at a site, at one per cent of the value or volume of production in the sixth year, rising by one point a year to seven per cent in the twelfth year and thereafter, with an exemption for a developing State that is a net importer of the mineral concerned. The payments are made through the International Seabed Authority, which distributes them on equitable sharing criteria. It is interesting because it is the one place where the common heritage principle reaches into an area under national jurisdiction, and because it has barely been applied, production beyond two hundred miles having only recently begun.