Carbon Capture Legal Programme

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United Nations Convention on the Law of the Sea, 1982 (UNCLOS)

Date of signature: 10 December 1982
Entry into force: 16 November 1994
Geographical scope: All areas of the world’s seas.
Contracting Parties: Status of ratifications as of 20 September 2013

What are the aims and requirements of the Convention?

UNCLOS entered into force in 1994 and was established to provide an overarching international agreement regulating the various uses of the world’s oceans and seas. The scope of the Convention is very broad and provides what has been termed a ‘constitution for the oceans’, covering the utilisation of resources, shipping, marine research, the exploitation of the exclusive economic zone (‘EEZ’) and continental shelf, and the prevention and avoidance of marine pollution. The Convention contains broad principles and provisions, allowing its Contracting Parties to create more precise national regulations with regard to the marine environment.

UNCLOS and zones of the sea

An important aspect of UNCLOS is its consideration of various parts of the ocean; the various zones prescribed under this Convention are used in other international marine laws. The sea is in effect divided into different zones and areas, with differing rights and duties applying to each separate sector. “Nations have the greatest amount of coastal jurisdiction and control over the waters closest to shore with increasing responsibility to accommodate uses by other nationals as the distance from the shore increases” (Purdy, 2007).
The Convention divides the sea into the following zones:

  • The area of ocean immediately adjacent to the coastline and extending to up to 12 miles out to sea is known as the Territorial Sea. The coastal State retains full sovereignty over this area of the sea.
  • An area contiguous to the territorial sea, called Contiguous Zone, which extends to a maximum of 24 nautical miles from the coast. In this area, the coastal state can prevent and punish ‘infringement of its customs, fiscal, immigration or sanitary laws and regulations’ which occurs within its territory or territorial sea (UNCLOS Article 33).
  • The Exclusive Economic Zone (‘EEZ’), which extends from the end of the territorial sea and out to a maximum distance of 200 miles from the coast, provides the coastal state with sovereign rights of exploration, exploitation and management of natural resources in both the waters themselves and the seabed below. States have rights with regard to the protection and preservation of the marine environment in their EEZ, as well as the construction, operation and use of installations and structures at sea. The EEZ is not a natural geographic area that belongs inherently to the State, unlike the Continental Shelf. Instead, it is a legal creation whose existence must be declared by the state in order to benefit from its specific legal regime. Not all states have declared an EEZ; the UK for example relies upon its Continental Shelf rights under the Geneva Convention on the Continental Shelf 1958.
  • UNCLOS also conveys sovereign rights upon coastal States with regard to the Continental Shelf. This area covers the seabed and subsoil of the submarine areas that extend beyond the coastal state’s territorial sea throughout the natural prolongation of its land territory to the outer edge of the continental margin, or to a distance of 200 nautical miles from the coast if the continental margin does not extend up to that distance (UNCLOS Article 76 (1)). Although its breadth can vary from state to state, the continental shelf is limited to either 350 nautical miles from the coast or 100 nautical miles from a line connecting the depth of 2,500 metres. A state is entitled to explore and exploit the natural resources of the seabed and subsoil of the continental shelf, which include ‘mineral and other non-living resources of the seabed and subsoil together with living organisms belonging to sedentary species’ (UNCLOS Article 77(4)). States are entitled under UNCLOS to lay pipelines on the continental shelf, in order to reasonably explore or exploit their natural resources (UNCLOS Article 79).
  • Beyond the EEZ or the Continental Shelf, the Convention establishes the regime of the High Seas, which is an area where all states enjoy freedom of fishing, subject to certain conditions and prerogatives accorded to the coastal state, and are required to conserve living resources (UNCLOS Articles 116-117). UNCLOS also regulates the exploitation of the seabed and ocean floor beyond national jurisdiction in a zone called ‘the Area’. No state can exercise sovereignty or sovereign rights over the Area and its natural resources as they are ‘common heritage of mankind’ (see UNCLOS Part XI). The Convention also establishes an International Seabed Authority to regulate activities in this communal zone.

Protection of the marine environment

UNCLOS also contains explicit provisions for the protection of the marine environment. Under Article 192, states are obliged to ensure the protection and preservation of the marine environment in each territorial zone of the sea; whilst Article 194 requires them to take the necessary measures, using the best practicable means, to ‘prevent, reduce and control pollution of the marine environment from any source’. States are required to ensure that their activities do not prejudice the environment of other states and must adopt laws and regulations which protect the marine environment from pollution emanating from land-based activities, seabed activities subject to national jurisdiction, dumping, vessels, and through the atmosphere.
Dumping is defined under UNCLOS as the deliberate disposal at sea of wastes or other matter from vessels, aircraft, platforms and other man-made structures, and does not include the placement of material for purposes ‘other than mere disposal’. Dumping by coastal states is permitted within their EEZ, provided that it does not impinge upon the rights or the environment of other states, or upon areas beyond national jurisdiction. UNCLOS also allows for dumping to take place on the continental shelf, provided the coastal state adheres to certain rights and requirements similar to those provided in relation to the EEZ.

  • UNCLOS does not expressly prohibit CCS activities, but its provisions may well have an impact where the activities are deemed to constitute pollution, which is defined in Article 1(4) as:
  • ‘the introduction by man, directly or indirectly, of substances or energy into the marine environment, including estuaries, which results or is likely to result in such deleterious effects as harm to living resources and marine life, hazards to human health, hindrance to marine activities, including fishing and other legitimate uses of the sea, impairment of quality for use of sea water and reduction of amenities’.
  • There is no conclusive opinion as to whether CCS would constitute pollution in accordance with this definition.
  • UNCLOS applies to the seabed and its subsoil. However, there remains uncertainty as to whether its provisions would apply in order to regulate CCS activities undertaken beneath the subsoil.
  • The right of a coastal state to exploit its EEZ is, to some extent, curtailed by the provisions of Part V of UNCLOS. The Convention places some restrictions upon States with regard to the erection of installations and structures in their EEZ. Article 56 requires states to ‘have due regard to the rights and duties of other States’ when undertaking activities in the EEZ; whilst Part V prohibits the placement of installations, structures and their accompanying safety zones where they may interfere with recognised international sea lanes, which are essential to international navigation.
  • Under the provisions of UNCLOS, the transport of CO2, by ship or pipeline, to an injection platform could be considered as dumping and subject to the requirements of the Convention described above. The London Convention of 1972 and the later Protocol of 1996 contain global rules and standards with regard to dumping and marine pollution. Contracting Parties to both UNCLOS and the London Convention should follow the broad legislation in this field.

Recent developments

A clarification or amendment could resolve the mentioned legal issues concerning the legality of CCS under UNCLOS. At present, however, modifications or amendments are not on the Agenda of the Contracting Parties.


The analysis in this section was developed under the UCL Carbon Capture Legal Programme, and is reproduced with kind permission of University College London.