Ocean Areas

Law of the Sea

UNCLOS III: Divisions of Ocean Areas

Note: for information on United Nations Convention on Law of the Sea III (UNCLOS III), please see here.

By Daniel Hollis.

One of the most powerful features of UNCLOS is that it settled the question of the extent of national sovereignty over the oceans and seabed. Parts II, V, VI, and VII establish the various regions of the oceans, who has sovereignty over each, and to what degree. The following sections explain both how the maritime regions are divided and the sovereign powers that nations may exercise over each region.

Baselines

Diagram of the various regions of the ocean over which a State may exercise sovereignty.
The baseline is the boundary from which a nation may begin measurements to determine the portion of the adjacent oceans or continental shelf over which it may exercise sovereignty. Except in some special cases, the baseline is the low-water line along the coast.[1] Detailed explanations of how baselines are determined are provided in Articles 5-7 and 9-14. Special rules have been established for determining the baselines of archipelagic nations (nations that consist of a number of small islands such as the Philippines) and can be found in Article 47.

Internal Waters

Internal waters are those that are contained on the landward side of the baseline.[2] These waters fall under the exclusive sovereignty of the nation in which they are contained.

Territorial Sea

Article 3 of UNCLOS declares that a nation may establish a territorial sea that extends up to 12 nautical miles from the baselines. Within the territorial sea, a nation has exclusive sovereignty over the water, seabed, and airspace.[3] The treaty establishes that all nations have the right of innocent passage through the territorial sea of another nation and that, outside certain conditions, the nation laying claim to the territorial sea cannot hamper innocent passage of a foreign vessel.[4] UNCLOS adopted the basic concepts of the territorial sea and the right of innocent passage that had been codified in the Convention on the Territorial Sea and the Contiguous Zone, but the new treaty went a step further by establishing the limits of a nation’s territorial sea.

By the late 1960’s many nations recognized a 12-mile limit to the territorial sea. At the start of the UNCLOS, only twenty-five nations maintained the traditional claim of 3 nautical miles. Sixty-six nations were claiming 12 nautical miles, fifteen nations claimed between 4 and 10 nautical miles, and eight nations were claiming an astounding 200 nautical miles. Smaller nations, including those without large navies or merchant fleets, favored a larger territorial sea in order to protect their coastal waters from infringements by more powerful nations. The world’s major naval and maritime powers, however, pressed for the 3-mile rule because the 12-mile rule would have placed over 100 straits used for international navigation under the exclusive sovereignty of other nations. Some of these included the Strait of Gibraltar (the only open access to the Mediterranean), the Strait of Hormuz (the only passage to the oil-producing Persian Gulf and Gulf of Oman nations), and the Strait of Malacca (the main route connecting the Pacific and Indian Oceans).[5]

Remembering that the Cold War was still ongoing during the Convention, smaller nations were particularly concerned about the possibility of threats to their national security posed by warships of foreign nations or even the possibility of becoming embroiled in the conflicts of foreign powers. In an attempted compromise, the small nations offered the larger maritime powers the right of innocent passage, however the maritime powers were not satisfied with this offer. The problem, in the view of the great powers, was that restrictions to innocent passage would prohibit covert movements of vessels (such as submarines) and did not guarantee overflight rights, thereby creating a security risk.[6]

In the end, the parties came together to form a compromise known as “transit passage.” Applied specifically to straits that would otherwise fall within the territorial sea of a nation, transit passage applies to straits used for international navigation between one part of the high seas to another and allows for “navigation and overflight solely for the purpose of continuous and expeditious transit of [a] strait….”[7] In all other ways aside transit passage, the waters of a strait still remain the territorial sea of the adjacent nation.[8]

Contiguous Zone

The Contiguous Zone is a region of the seas measured from the baseline to a distance of 24 nautical miles. Within this region, a nation may exercise the control necessary to prevent the infringement of its customs, fiscal, immigration or sanitary laws and regulations within its territory or territorial sea, and punish infringement of those laws and regulations committed within its territory or territorial sea.[9]

Exclusive Economic Zone

The Exclusive Economic Zone or “EEZ” is a region that stretches a distance of no more than 200 nautical miles from a nation’s baselines.[10] Generally, the rules regarding the High Seas, set forth in Articles 88 to 115, apply to the EEZ.[11] Within its EEZ, a nation may explore at exploit the natural resources (both living and inanimate) found both in the water and on the seabed, may utilize the natural resources of the area for the production of energy (including wind and wave/current), may establish artificial islands, conduct marine scientific research, pass laws for the preservation and protection of the marine environment, and regulate fishing.[12]

One of the primary purposes behind establishing the EEZ was to clarify the rights of individual nations to control the fish harvests off their shores. The 200-mile limit established by UNCLOS is not an arbitrary number. It is derived from the fact that the most lucrative fishing grounds lie within 200 nautical miles from the coast as this is where the richest phytoplankton (the basic food of fish) pastures lie.[13]

The creation of the EEZ gave coastal nations jurisdiction of approximately 38 million square nautical miles of ocean space. The world’s EEZs are estimated to contain about 87% of all of the known and estimated hydrocarbon reserves as well as almost all offshore mineral resources. In addition, the EEZs contain almost 99% of the world’s fisheries, which allows nations to work to conserve the oceans vital and limited living resources.[14]

Continental Shelf

Unlike the other boundaries that have been thus far discussed, the continental shelf is a real, naturally-occurring geological formation. It is a gently sloping undersea plain between the above-water portion of a landmass and the deep ocean. The continental shelf extends to what is known as the continental slope, a point at which the land descends further and marks the beginning of the ocean itself. It is host to most of the world’s oceanic plant and animal life and plays a vital role in energy production, from offshore oil and gas reserves to renewable energy resources.[15]

When UNCLOS refers to the continental shelf, however, it is using “continental shelf” as a legal term.[16] While the EEZ captures a lot of the continental shelf for many countries, it does not capture all of it. As such, UNCLOS includes provisions for nations to lay claim to a continental shelf that exceeds 200 nautical miles from the baseline by establishing the foot of the continental slope as set forth in Article 76, paragraphs 4-7. These provisions allow for an extension of an additional 150 nautical miles from the baseline or 100 miles from the 2,500 meter depth.[17] Nations exercise over the shelf the sovereign right to explore and exploit the non-living natural resources of the continental shelf as well as the living organisms that live on the seabed itself.[18] The water above the portion of the continental shelf that is not contained within the EEZ remains part of the high seas (as does the airspace above that area).[19] Nations wishing to request an extension of sovereignty over an extended portion of their naturally occurring continental shelf must do so within 10 years of UNCLOS coming into force for that particular nation.[20]

The extension of sovereignty to the extended continental shelf comes with a price. A nation that exploits resources on the continental shelf beyond the 200 nautical mile mark is allowed five years in which to develop and exploit the resources of the shelf without charge. Starting on the sixth year, a nation has to pay 1 percent of the value of the resources produced from the site. The rate of payments increase by 1 percent for each year until the twelfth year and is capped at 7 percent thereafter. Developing nations are exempted from this provision.[21] Revenues generated from these operations are deposited with the International Seabed Authority and equally distributed among national parties to UNCLOS.[22]

High Seas

Waters beyond a nation’s EEZ are considered to be the high seas.[23] The high seas are still governed the “freedom of the seas” concept, albeit a modified version. Just as with the classical version, no nation my lay claim to any portion of the high seas.[24] Per the terms of the treaty, “[t]he high seas are open to all States, whether coastal or land-locked.”[25] On the high seas, nations are permitted freedom of navigation and overflight, freedom to lay submarine cables and pipelines, freedom to construct artificial islands, freedom of fishing, and freedom of scientific research.[26] Other provisions regarding the high seas include a prohibition on the transport of slaves, piracy, illegal drug trafficking, and the suppression of unauthorized radio or television broadcasting.[27]

The Area

The “Area” is the seabed and ocean floor that is beyond the limits of national jurisdiction.[28] This is the portion of the seabed that is beyond the EEZ or the recognized continental shelf of a country. It would be inaccurate to say that the Area is the seabed underneath the high seas, since the high seas can overlap portions of continental shelf that are subject to national sovereignty. The Area is particularly unique in that UNCLOS designates it and the resources it contains as “the common heritage of mankind.”[29] No nation is allowed to lay claim to any part of the Area or its resources. Regarding the resources, “[a]ll rights in the resources of the Area are vested in mankind as a whole….”[30] As a result, companies that wish to exploit the mineral resources of the Area will have to enter into a profit sharing agreement in which the profits derived from mineral resources captured in the Area will be shared with developing nations.

Resources

Notes and References

1. UNCLOS art 5.
2. UNCLOS art 8.
3. UNCLOS art 2.
4. UNCLOS art 17; UNCLOS art 24.
5. United Nations, The United Nations Convention on the Law of the Sea (A Historical Perspective), available at un.org/Depts/los/convention_agreements/convention_historical_perspective.htm (accessed 9 June 2010).
6. United Nations, The United Nations Convention on the Law of the Sea (A Historical Perspective), available at un.org/Depts/los/convention_agreements/convention_historical_perspective.htm.
7. UNCLOS art 37 and 38.
8. UNCLOS art 34.
9. UNCLOS art 33.
10. UNCLOS art 57.
11. UNCLOS art 58.
12. UNCLOS art 56; UNCLOS art 61-64.
13. United Nations, The United Nations Convention on the Law of the Sea (A Historical Perspective), available at un.org/Depts/los/convention_agreements/convention_historical_perspective.htm.
14. United Nations, The United Nations Convention on the Law of the Sea (A Historical Perspective), available at un.org/Depts/los/convention_agreements/convention_historical_perspective.htm.
15. OCS Alternative Energy and Alternative Use Programmatic EIS, The Outer Continental Shelf, available at https://ocsenergy.anl.gov/guide/ocs/index.cfm (accessed 14 June 2010); Department of the Navy Office of Naval Research, Ocean Regions: Ocean Floor – Continental Margin & Rise, available at https://www.onr.navy.mil/focus/ocean/regions/oceanfloor2.htm.
16. United Nations Division for Ocean Affairs and the Law of the Sea, The Definition of the Continental Shelf and the Criteria for the Establishment of its Outer Limits, available at un.org/Depts/los/clcs_new/continental_shelf_description.htm (accessed 14 June 2010).
17. UNCLOS art 76; United Nations Division for Ocean Affairs and the Law of the Sea, The Definition of the Continental Shelf and the Criteria for the Establishment of its Outer Limits, available at un.org/Depts/los/clcs_new/continental_shelf_description.htm; United Nations, The United Nations Convention on the Law of the Sea (A Historical Perspective), available at un.org/Depts/los/convention_agreements/convention_historical_perspective.htm.
18. UNCLOS art 77.
19. UNCLOS art 78.
20. UNCLOS Annex II, art 4.
21. Article 82.
22. United Nations, The United Nations Convention on the Law of the Sea (A Historical Perspective), available at un.org/Depts/los/convention_agreements/convention_historical_perspective.htm.
23. UNCLOS art 86.
24. UNCLOS art 89.
25. UNCLOS art 87.
26. UNCLOS art 87
27. UNCLOS art 99-109.
28. UNCLOS art 1.
29. UNCLOS art 136.
30. UNCLOS art 137.