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IBRU: Centre for Borders Research

Boundary news

Boundary news Headlines

CLCS rejects UK Ascension Island submission

(1 June 2010)

The United Nations Commission on the Limits of the Continental Shelf (CLCS) has recommended that the United Kingdom should not define the outer limit of its continental shelf around Ascension Island beyond 200 nautical miles from the island.

In its first major disagreement with a coastal state claiming rights over the resources of the outer continental shelf, the CLCS concluded that Ascension Island is a "volcanic ... pinnacle surrounded by the deep ocean floor" and that it is "distinct from the surrounding floor morphologically, geologically, geophysically and geochemically". In this context, the foot of slope points from which the UK measured its proposed continental shelf limit cannot be considered valid. However, the CLCS noted that this decision does not mean that islands, in general, cannot generate a continental margin that extends beyond 200 nautical miles.

In its May 2008 submission to the CLCS, the UK argued that Ascension Island generated nearly 200,000 square kilometres of continental shelf beyond 200 nautical miles, so the decision is certainly significant for the UK. Whether the Commission's approach will have any bearing on other continental shelf submissions based on volcanic islands remains to be seen.

Due to its isolated location, Ascension Island still generates rights over the resources of more than 440,000 square kilometres of sea and seabed within 200 nautical miles of the island.

Summary of the CLCS recommendations regarding the continental shelf of Ascension Island