Professor Peter Wadhams: A shrewd political move for a planet of finite resources

There is more than meets the eye about Russia's claim to the Arctic Ocean that is dramatised by their dive yesterday to the seabed in the Mir submersible.

The first is that the leader of the dive, Artur Chilingarov, has been described in the press as a "polar explorer". Indeed, that was how he started out; he was head of the Hydrometeorological Service of the USSR when the USSR existed. But later he became a wily and successful politician.

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This dive is a completely political exercise, designed to cement Russia's claim to about half the area of the Arctic Ocean.

The key is the Lomonosov Ridge, which stretches across the Arctic Ocean from Siberia to north Greenland. The Law of the Sea permits coastal states to extend their jurisdiction into the deep ocean provided the geology of the seabed is similar to that of the nearby continental shelf. This allows a lot of argument. Denmark has already made a widely-derided claim to the North Pole region based on the continuity of the Lomonosov Ridge with the continental shelf of north Greenland. Unfortunately for Denmark, there is a deep trough separating the ridge from the Greenland continental shelf, in a place where my research group has been working.

Russia's claim is not much more solid, as the ridge at its Siberian end also appears to be separated from the Siberian shelf by another trough. Geologically, it appears the ridge was once part of the Siberian shelf which was pushed away by seafloor spreading, so perhaps the Russian claim has slightly more substance .

The point has been made that the continued deployment of UK submarines in the Arctic is a sign of British concern about Russian political ambitions. But I believe the strongest motive in the Navy's thinking is the desire to map the thinning of sea ice under global warming. I sailed on board this year's voyage by HMS Tireless to carry out such measurements. The disappearance of Arctic sea ice will have a major impact on resources, transport, ecology and international relations, so the Navy is being far-sighted as well as strategically shrewd. As the ice melts, pressure from Russia in the race for oil, fisheries, and maritime routes, is likely to continue.

Peter Wadhams is Professor of Ocean Physics, University of Cambridge