Island or Rock

The convention's article on islands has three short paragraphs, and the third may control more of the world's ocean than any other sentence in international law.

The first paragraph defines an island: a naturally formed area of land, surrounded by water, which is above water at high tide. The second gives islands the same zones as any other land territory: territorial sea, economic zone and continental shelf. The third makes an exception. Rocks which cannot sustain human habitation or economic life of their own shall have no exclusive economic zone or continental shelf.

The arithmetic is what makes this matter. A circle of twelve nautical miles around an isolated point encloses about 1,550 square kilometres of sea. A circle of two hundred nautical miles encloses about 430,000, which is more than the land area of Germany. A single feature on the right side of that sentence can carry an ocean.

The sentence was vague on purpose. In the negotiations of the 1970s, states with small islands wanted them to count and states without them wanted the high seas protected, and the compromise was wording each side could read its own way. Human habitation, economic life and of their own were left undefined, and for more than thirty years no tribunal set out what they meant.

The vagueness created an incentive. If a feature's status depends on whether it can sustain people or economic activity, the state that claims it has every reason to make it look as if it can.

Okinotorishima is the clearest case. It is Japan's southernmost point, a coral reef in the Philippine Sea where at high tide only two small outcrops stay above the water. Since the late 1980s Japan has protected them with steel and concrete barriers to stop the sea wearing them away, and it claims a full economic zone around them. China and South Korea say they are rocks under the third paragraph and entitled to twelve miles at most. Japan's position is that the first paragraph is satisfied, since the outcrops are naturally formed and above water at high tide, and that this is enough.

Britain chose the opposite course with Rockall, a granite stack in the North Atlantic that it formally annexed in 1955. For two decades it used Rockall as a base point for a two-hundred-mile fishery zone. When Britain acceded to the convention in 1997 it redrew its fishery limits without Rockall, accepting in effect that the stack was a rock under the third paragraph.

Then came the first detailed test. In 2016 the tribunal in the South China Sea arbitration had to decide whether any of the Spratly features was an island in the full sense, and it read the sentence strictly.

Capacity, it said, should be judged by the feature's natural condition, not by what had been built on it. Human habitation meant a stable community of people for whom the feature is home, not a garrison or a rotating team of workers supplied from outside. Economic life of its own meant activity based on the feature itself, not extraction run from elsewhere. Applying that test, the tribunal held that even Itu Aba, the largest naturally formed feature in the Spratlys, with fresh water, vegetation and a Taiwanese garrison, was in law a rock.

Taiwan rejected the finding, and so did China, which claims Itu Aba as well. Some lawyers thought the test went further than the text required. Others thought it was the only reading that kept the third paragraph from meaning nothing.

That last point is the strongest case for strictness. If concrete, desalination plants and a rotating garrison can turn a rock into an island, then any state with money can enclose a large stretch of what would otherwise be high seas, and the commons shrinks with every engineering contract. The strongest case on the other side is practice. For decades states have drawn full zones around small, remote, uninhabited features, and a rule applied strictly now would unsettle maps far from the South China Sea.

Notice who stands where. Japan welcomed the 2016 award as final and legally binding on the parties, and maintains its claim around Okinotorishima. Other states that applauded the strict reading in the Spratlys hold full zones around small features of their own. None of this makes them hypocrites in any unusual sense. It makes them states.

That is the habit worth taking from this chapter. When a government argues for a strict reading of a rule, ask where the rule would bite on its own territory. Its answer, or its silence, tells you whether it is arguing law or interest.