Expanding Shelves
As you walk into the ocean, crossing the low-water baseline, the ground gently declines. If you walk out far enough – of course, by now, well underwater – you will reach a point where it suddenly falls away from your feet. This may be for many reasons: a shift in the sands; or you may be teetering at the edge of a canyon. Or you may have discovered for yourself the edge of the geological formation known as the continental shelf.
The continental shelf is a ubiquitous feature of coasts around the world. It is not, however, a uniform terrain. Some coasts, such as the Atlantic seaboard of the United States, have a broad continental shelf – gradually declining over a long distance – others, like the US’s own Pacific seaboard, have narrow ones. Some shelves are relatively smooth; others are fissured and fractured by ridges and canyons. Continental shelves give on to a steeply falling continental slope, and then a gradually declining continental rise where the sliding sediments gather. Together, the three comprise the continental margin, distinct in composition from the abyssal plain: the floor of the deep ocean.
Until the Second World War, the shelf was largely governed by the principle of the freedom of the sea. But in 1945, following the discovery of petroleum deposits off its eastern coast, the US issued the Truman Proclamation, asserting jurisdiction over the resources of the continental shelves which were ‘naturally appurtenant’ to its coasts. It thereby set off a long process of ever expanding claims. The initial US claim, limited to the part of the shelf less than 100 fathoms under water, comprehended territory only a few miles out into the ocean (but, given its long coastlines, still a significant claim, obtaining, for ‘the price of printer’s ink’, effective sovereignty ‘over submerged lands equal in [total] area to the Louisiana Purchase’).
However this limit was overcome by two forces. The first was pressure from oil companies, which had developed the capability to extract oil in deeper waters and encouraged states to bring larger stretches of the shelf under national jurisdiction, so that they could offer corporations secure and exclusive tenure over drilling sites.
The second was pressure from states which had narrow continental shelves (such as many Latin American ones), and thus rejected a depth criterion altogether. They argued instead for a distance criterion that would allow all states rights to equal widths of the seabed, regardless of whether the area incorporated included the slope, or rise or even the abyssal plain.
The 1982 Convention on the Law of the Sea reflects this position, designating 200 miles of the seabed as the ‘continental shelf’ irrespective of actual physical structure. If its dismissal of geography sits oddly juxtaposed with the repetition that the shelf comprises ‘the natural prolongation’ of the state’s coastal land, the Convention reminds us that geography is not irrelevant; merely, it is no longer inconvenient, for it does not determine the minimum claim.
States can provide geological evidence of natural prolongation to claim the continental margin beyond 200 miles – up to an even more generous limit. The part of the seafloor which is qualified as the continental shelf is placed within the jurisdiction of states, and excluded from the remainder of the area designated as the common heritage of mankind.
In 2007, Russia planted its flag on the Arctic seafloor, staking exclusive claim to its vast oil and gas deposits, on the basis that melting ice had revealed a longer continental shelf. Many reacted in tones of outrage or alarm. The Canadian foreign minister stated, on television:
“This isn’t the 15th century. You can’t go around the world and just plant flags and say: ‘We’re claiming this territory’.”
It is of course the global warming caused by the – law facilitated – extraction of fossil fuels that is melting Arctic ice and bringing its hydrocarbons into view. We now rightly look to the law for solutions to climate change, but we might also keep in mind that the problems it must confront have been enabled by its own regimes.
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