2.4.1 Natural Prolongation vs Distance
The definition of continental shelf employed in Art. 76 (1) UNCLOS gave a new
meaning to the principle of natural prolongation, one radically different from the one
adopted in the 1958 CSC,
63 which defined the continental shelf in terms of depth and
ability of the coastal state to exploit natural resources of the seabed. In other words,
the CSC did not expressly require the need for physical continuity between seafloor
and landmass, although such requirement be implicit in the depth criterion and the
need for the shelf to be not too distant from the surface. That criterion was different
from UNCLOS’ physical identity (or natural prolongation) and distance.
The element of physical identity of the submerged land could be seen already in
the 1945 Truman Proclamation, where the continental shelf was construed as “the
extension of the landmass of the coastal nation and thus naturally appurtenant to it”
(emphasis added). In fact, if the geological connection of the continental shelf with
the landmass was the chief argument espoused by the Proclamation, it followed
logically that the contiguous nations may exercise exclusive jurisdiction over continental shelf resources. That was the birth of the principle of natural prolongation of
the territory of the coastal state that happens to be covered by ocean.
64 Despite the
principle’s slight neglection in the 1958 CSC, it was later absorbed and
complemented at UNCLOS, which additionally bonded natural prolongation with
the geomorphological notion of continental margin, so as to reinforce the physical
relationship between them. According to newer provisions, the continental margin
equals the continuous and uninterrupted natural prolongation of the landmass seawards, pursuant to UNCLOS Art. 76 (4) (a) (i).
The other criterion, of distance, attributed to coastal states a continental shelf of
up to 200 nm, “where the outer edge of the continental margin does not extend up to
that distance”.
65 Practically, to say that coastal states have a continental shelf of
200 nm even where the continental margin does not “naturally prolong” until that
breadth, is to say that states will exercise functional jurisdiction over natural
resources of the seafloor up to that limit, whatever those resources may be. It does
not mean that the Convention sees a geological continental shelf where none exists,
but simply that it awards coastal states exclusive and sovereign rights over natural
resources of the seafloor until 200 nm, even if that seafloor is the oceanic crust.
As noticeable from the above, the notions of natural prolongation and continental
margin are closely interrelated.
66 However, natural prolongation is not the same as
continental margin, nor outer continental shelf. Those are similar, but separate
concepts. Whereas the continental margin is the geomorphological notion of the
63 Kwiatkowska (1991), p. 157.
64 Townsend-Gault (2014), p. 78.
65 UNCLOS, Art. 76, paragraph 1, on the definition of continental shelf.
66 That finding was confirmed by ITLOS. See Dispute concerning delimitation of the maritime
boundary between Bangladesh and Myanmar in the Bay of Bengal (Bangladesh/Myanmar), Order
of 14 March 2012, ITLOS Reports 2011, 4, para 437.
2.4 Core Principles of the Continental Shelf Regime
35
The definition of continental shelf employed in Art. 76 (1) UNCLOS gave a new
meaning to the principle of natural prolongation, one radically different from the one
adopted in the 1958 CSC,
63 which defined the continental shelf in terms of depth and
ability of the coastal state to exploit natural resources of the seabed. In other words,
the CSC did not expressly require the need for physical continuity between seafloor
and landmass, although such requirement be implicit in the depth criterion and the
need for the shelf to be not too distant from the surface. That criterion was different
from UNCLOS’ physical identity (or natural prolongation) and distance.
The element of physical identity of the submerged land could be seen already in
the 1945 Truman Proclamation, where the continental shelf was construed as “the
extension of the landmass of the coastal nation and thus naturally appurtenant to it”
(emphasis added). In fact, if the geological connection of the continental shelf with
the landmass was the chief argument espoused by the Proclamation, it followed
logically that the contiguous nations may exercise exclusive jurisdiction over continental shelf resources. That was the birth of the principle of natural prolongation of
the territory of the coastal state that happens to be covered by ocean.
64 Despite the
principle’s slight neglection in the 1958 CSC, it was later absorbed and
complemented at UNCLOS, which additionally bonded natural prolongation with
the geomorphological notion of continental margin, so as to reinforce the physical
relationship between them. According to newer provisions, the continental margin
equals the continuous and uninterrupted natural prolongation of the landmass seawards, pursuant to UNCLOS Art. 76 (4) (a) (i).
The other criterion, of distance, attributed to coastal states a continental shelf of
up to 200 nm, “where the outer edge of the continental margin does not extend up to
that distance”.
65 Practically, to say that coastal states have a continental shelf of
200 nm even where the continental margin does not “naturally prolong” until that
breadth, is to say that states will exercise functional jurisdiction over natural
resources of the seafloor up to that limit, whatever those resources may be. It does
not mean that the Convention sees a geological continental shelf where none exists,
but simply that it awards coastal states exclusive and sovereign rights over natural
resources of the seafloor until 200 nm, even if that seafloor is the oceanic crust.
As noticeable from the above, the notions of natural prolongation and continental
margin are closely interrelated.
66 However, natural prolongation is not the same as
continental margin, nor outer continental shelf. Those are similar, but separate
concepts. Whereas the continental margin is the geomorphological notion of the
63 Kwiatkowska (1991), p. 157.
64 Townsend-Gault (2014), p. 78.
65 UNCLOS, Art. 76, paragraph 1, on the definition of continental shelf.
66 That finding was confirmed by ITLOS. See Dispute concerning delimitation of the maritime
boundary between Bangladesh and Myanmar in the Bay of Bengal (Bangladesh/Myanmar), Order
of 14 March 2012, ITLOS Reports 2011, 4, para 437.
2.4 Core Principles of the Continental Shelf Regime
35