Hop, hop, hop, plop

STATES can die in obvious ways. They can be conquered, merge with the country next door, or cease to exist as a “geopolitical reality”, as the leaders of Russia, Ukraine and Belarus triumphantly said of the Soviet Union in 1991, after killing it off. But what if a state ceases to exist as a physical reality—if it sinks, Atlantis-like, under the waves?

For low-lying islands like the Maldives or Kiribati, that is a very real possibility. Sea levels have risen by 20 centimetres (8 inches) in the past century. By 2100 they may surge by five times that, or even more if Greenland's ice sheet starts to collapse. Long before an islet submerges, it will become uninhabitable as inland waters become brackish and sea-defences fail.

So the legal implications of sinking islands are preoccupying environmental lawyers. Can there be such a thing as a submarine state? According to one definition, a state needs a clear territory, a permanent population and the ability to deal with other states. From a league or so under the sea, that sounds hard.

It may be a few decades before any states actually vanish, but a related problem—over rights to exploit minerals and fish, and how these are affected by receding coasts—is in even more urgent need of solution, says David Wei of FIELD, an NGO that looks at environmental law.

Under the Law of the Sea, coastal states and islands are entitled to territorial waters of 12 nautical miles, and an exclusive economic zone of 200 miles—and may claim rights over a continental shelf up to 350 miles away. Where coasts recede because of rising seas, so do the baselines from which such zones are calculated, many scholars say. But some authorities think baselines, once established, could be deemed permanent. That would protect countries from the effects of rising seas.

Adopting this idea would ease, but not totally solve, the legal problems created by disappearing states, according to Rosemary Rayfuse, a law professor at Australia's University of New South Wales. The people of a vanishing atoll might somehow retain their rights even if they migrated en masse to another country, or merged with another state, bringing their entitlements as a sort of dowry.

Yet current law lays down that only islands can support economic areas. Mere rocks, places which “cannot sustain human habitation or economic life of their own”, have no such privilege. For that reason, Japan has been spending lavishly on shoring up what it calls Okinotori island, defying the Chinese claim that the place is just a rock. If rocks confer no economic rights, then the tips of palm trees, peeping over the waves, presumably cannot either.

In practice, the world would probably err on the generous side in dealing with nations exiled by waves. If a threatened island managed to keep an artificial, floating structure, occupied by caretakers, it could probably maintain its claim to statehood, according to Jenny Grote Stoutenburg, a participant in a conference this week at Columbia Law School.

Ms Rayfuse, meanwhile, thinks the world should rediscover the idea of “deterritorialised states”—entities like the Order of Saint John, a league of knights that was treated as a sovereign entity although it controlled virtually no territory. A new type of landless authority could still enjoy the rights, including maritime exploitation rights, that the nation used to have before the waves rolled in. If football authorities and social networks can turn into states of sorts, who needs a patch of sand?