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The juridical continental shelf, a new term in international law

by Jørgen Taagholt

The United Nations Law of the Sea Convention
The United Nations started the Third Law of the Sea Conference in Caracas, Venezuela, in 1974, and the conference was not concluded until 1982.
For a long period, the freedom of the high seas has been the dominating principle, which was often misused. The technologically leading countries were using more and more of their advanced technology to vacuum clean the rich fishing areas on the third countries' continental shelf. Leading mining companies started to develop a technique, which could utilise the mineral resources of the ocean floor. The nonequal division of resources and technological possibilities to utilise such resources caused a majority of countries, especially from the third world, to feel a need to protect their rights to the resources in their coastal area.
During this very long conference, several states extended their fishery or economic zones up to 200 nautical miles, so the conference had to face "creeping jurisdiction" as a fait accompli.
The new convention was formally accepted on December 10, 1982, although USA voted against and the Soviet Union abstained. The Danish Government, as one of 119 nations, signed the convention in December 1982. The convention then has to be ratified, which to Denmark and most of the democracies means that the convention has to be presented and accepted by the different national parliaments.
The convention was in force on November 16, 1994, one year after its ratification by 60 nations. After an agreement was obtained in 1994 in order to solve problems related to international control of deep sea resources, most of the industrial world, including member nations of the European Union, started the ratification process. The convention confirms the new established international law practice, under which a nation has the right to adjust the basic line, extend the territorial water from 3 to 12 nautical miles, establish a fishery zone up to 200 nautical miles and extend the fishery zone to an economic zone. This is defined as a zone, where the coastal state has exclusive rights to all living and nonliving resources and to utilise such resources as wave, current and wind energies to control pollution and maritime research.
Danish claim for an exclusive economic zone
Based on the Danish Act no 411 of May 22, 1996, Denmark established an exclusive economic zone round Denmark. The act opens the possibility of administratively introducing an exclusive economic zone round the Faroe Islands and Greenland when appropriate, and when the local Home Rule Government has accepted such extension.
It is expected that in 1998 Denmark/Greenland will establish an exclusive economic zone round Greenland, giving the coastal state the right to all living and nonliving resources, and to such resources as wave, current and wind energies, and the control of pollution and maritime research.
The Juridical Continental Shelf
By ratifying the 1982 Law of the Sea Convention the coastal state has additionally, according to Article 76 of the Convention, a means of ensuring international recognition of its national sovereign rights and jurisdiction in the marine areas beyond the limits of the 200 nautical miles exclusive of the economic zone on a submerged prolongation of the land mass.
In accordance with Article 76 in the new UN Law of the Sea Convention a new term "juridical continental shelf" has been defined. The "juridical continental shelf" differs from the physiographic continental shelf. The new term encompasses three physiographic components of the continental margin: shelf, slope and rise (fig. 1).
Definition of the juridical shelf
According to Article 76, the juridical shelf can be defined either by the distance formula or by the sediment thickness formula. If the distance formula is used, the outer limit of the juridical continental shelf is defined by fixed points 60 nautical miles from the foot of the continental slope, fig. 2.
If the sediment thickness formula is used, the outer limit of the juridical continental shelf is defined by fixed points, at each of which the thickness of sedimentary rocks is at least 1% of the shortest distance from such point to the foot of the continental slope, fig. 3.
Such fixed points defined either by distance or by thickness formula must be separated by not more than 60 miles. The outer limit for the juridical continental shelf cannot exceed 350 nautical miles from the baseline or 100 nautical miles from the 2,500 m isobath.
Limitation of the prolongation
The extension shall not exceed 350 nautical miles from the baseline from which the breadth of the territorial sea is measured, or shall not exceed 100 nautical miles from the 2,500 m isobath, which is a line connecting fixed points at a depth of 2,500 metres.
The national jurisdictions for the extended "juridical continental shelf" will apply to the nonliving resources of the seabed and its subsoil, and to sedentary living resources that dwell on the seafloor, thus the "juridical continental shelf" is not identical with the exclusive Economic Zone.
Such fixed points defined either by distance or by thickness formula must be separated by not more than 60 miles. The outer limit for the juridical continental shelf cannot exceed 350 nautical miles from the baseline or 100 nautical miles from the 2,500 m isobath.
UN Commission for the Continental Shelf
Accordingly, there is a demand for comprehensive bathymetric mapping of the seafloor in the marine area north of Greenland, defining the shelf and the foot of the continental slope, which is the line along the base of the slope where the gradient of the seafloor undergoes its maximum change and additionally the 2,500 m isobath. Comprehensive seismic investigations are also needed to map the thickness of the sedimentary layers on the slope and the sea floor in the continental margin.
In 1997 the Commission for the Continental Shelf was established, responsible for giving advice concerning claims for extension of the continental shelf and evaluating the claims based on presented scientific documentation. This commission has 21 members, covering internationally recognised experts in bathymetry, geophysics and/or geology. The decisions taken by the commission are binding. European states are represented by experts from Germany, Ireland and Norway.
After ratification of the Law of the Sea Convention, the coastal state has 10 years to define the outer limits of the "juridical continental shelf" and must present the claim and relevant physiographic documentation for the extension exceeding the 200 nautical miles to the Commission. This documentation has to be accepted by the Commission for the Continental Shelf.
As shown in fig. 4, the boundary line in West and East Greenland is defined as the equidistant line with neighbouring states or lines defined, based on bilateral agreement.
In southern Greenland, where the continental margin is relatively narrow, the juridical shelf has a width of 200 nautical miles (app. 365 km) and will be identical with the Exclusive Economic Zone, EEZ.
In North and Northeast Greenland the continental shelf seems to be a natural prolongation in the Morris Jesup Plateau and the Lomonosov Ridge. Accordingly, Denmark has a demand for bathymetric, seismic and geophysical data collection in the sea North and Northeast of Greenland.
As shown in fig. 5, the physiographic continental shelf north of Norway inclusive of Svalbard and especially north of Russia, is very large, up to app. 1000 nautical miles wide, and thanks to Svalbard and the Russian Arctic archipelago, the Eurasian 200 miles economic zone might extend to the north, as indicated in the Canadian sketch shown in fig. 6. The physiographic continental shelf has much less width north of the American continent, comprising Alaska, Canada and Greenland.
The Geological Survey of Canada has started the geophysical program and has in 1994 presented their maximum claims in the Polar Sea as shown in fig. 6, which indicates the possible prolongation outside the 200 nautical miles economic zone north of Canada.
To Denmark it is important to retrieve bathymetric and seismic data collected by other nations from Greenlandic waters and to build up a Greenlandic data base. At present several international scientific programmes are active in the Polar Sea (Arctic Submarine Science Program SCIEX; the IASC Bathymetric Data Base for the Arctic, Nansen Arctic Drilling Program, NAD; Arctic Climate System Study, ACYS; and Polar Margin Aeromagnetic Program, PMAP).
Danish participation in such projects gives Denmark the possibility of collecting some of the needed geophysical data and then define the Danish demand for further data collection for evaluation of possible national Danish claims for prolongation of the continental shelf north and northeast of Greenland.
Canada and Article 76 of the Law of the Sea. Open File 3209, 1994. Ottawa. Geological Survey of Canada
Bach, H. C. & Jørgen Taagholt, 1982. Greenland and the Arctic Region - resources and security policy. Copenhagen, The Information and Welfare Service of the Danish Defence.
Lilje-Jensen, Jørgen & Milan Tamsborg, 1995. The role of natural prolongation in relation to shelf determination beyond 200 nautical miles. - In: Nordic Journal of International Law 64, 619-645.
Nansen Arctic Drilling, Implementation Plan, 1997. Washington D.C., Joint oceanograhic Institutions.
Seafloor Characterization and Mapping Pod, 1997. New York, Columbia University, Lamont-Doherty Earth Observatory.
Taagholt, Jørgen, 1992. International Law of the Sea - in an Arctic Perspective. Nordic Arctic Research on Contemporary Arctic Problems. - In: Proceedings from Nordic Arctic Research Forum 1992. Aalborg, Aalborg University Press.
Verlaan, Philomene A., 1997. New Seafloor Mapping Technology and Article 76 of the 1982 UN Convention on the Law of the Sea. - In: Marine Policy, vol. 21, no. 5, 425-434.
Fig. 1. Source : Bach & Taagholt, 1982
Fig. 2.
Fig. 3.
Fig. 4. Source : Bach & Taagholt, 1982
Fig. 5. Source : Geological Survey of Canada
Fig. 6. Source : Geological Survey of Canada