As countries battle for control of North Pole, science is the ultimate winner

A competition for the North Pole heated up last month, as Canada became the third country to claim—based on extensive scientific data—that it should have sovereignty over a large swath of the Arctic Ocean, including the pole. Canada's bid, submitted to the United Nations's Commission on the Limits of the Continental Shelf (CLCS) on 23 May, joins competing claims from Russia and Denmark. Like theirs, it is motivated by the prospect of mineral riches: the large oil reserves believed to lie under the Arctic Ocean, which will become more accessible as the polar ice retreats. And all three claims, along with dozens of similar claims in other oceans, rest on extensive seafloor mapping, which has proved to be a boon to science, whatever the outcome for individual countries. The race to obtain control over parts of the sea floor has "dramatically changed our understanding of the oceans," says marine geophysicist Larry Mayer of the University of New Hampshire in Durham.

Coastal nations have sovereign rights over an exclusive economic zone (EEZ), extending by definition 200 nautical miles (370 kilometers) out from their coastline. But the 1982 United Nations Convention on the Law of the Sea opened up the possibility of expanding that zone if a country can convince CLCS that its continental shelf extends beyond the EEZ's limits.

Most of the 84 submissions so far were driven by the prospect of oil and gas, although advances in deep-sea mining technology have added new reasons to apply. Brazil, for example, filed an application in December 2018 that included the Rio Grande Rise, a deep-ocean mountain range 1500 kilometers southeast of Rio De Janeiro that's covered in cobalt-rich ferromanganese crusts.

To make a claim, a country has to submit detailed data on the shape of the sea floor and on its sediment, which is thicker on the shelf than in the deep ocean. The data come from sonar, which reveals seafloor topography, and seismic profiling, which uses low-frequency booms to probe the sediment. Canada's bid also enlisted ships to conduct high-resolution gravimetry—measurements of gravity anomalies that reveal seafloor structure. Elevated gravity readings are found over higher-density mantle rocks found in oceanic crust, and lower readings over lighter, continental structures. And the bid used analyses of 800 kilograms of rock samples dredged up from the sea floor, whose composition can distinguish continental from ocean crust.

The studies don't come cheap; Canada's 17 Arctic expeditions alone cost more than CA$117 million. But the work by the three countries vying for the Arctic—and that of dozens of others elsewhere in the world—has been a bonanza for oceanography. In the Arctic alone, the mapping has revealed several sunken mountains, previously missed or undetected by older sonar methods. Hundreds of pockmarks found on the Chukchi Cap, a submarine plateau extending out from Alaska, suggest that bursts of previously frozen methane have erupted from the seabed, a phenomenon that could accelerate climate change. And gaps discovered across submarine ridges allow currents to flow from basin to basin, with "important ramifications on the distribution of heat in the Arctic and on overall modeling of climate and ice melting," Mayer says.

Who owns the North Pole? Countries can clain the sea floor beyond the 200-nautical-mile (370-kilometer) ex - clusive economic zone (EEZ) if data show it to be an extension of the continental shelf (below). Russia, Denmark, and Canada have submitted overlapping claims in the Artic Ocean (right). Continental crust EEZ Outer limit of the extended continental shelf Oceanic crust Rise Slope Coastline EEZ line Danish claim Canadian claim Russian claim GREENLAND (Denmark) CANADA UNITED STATES RUSSIA North Pole Lomonosov Ridge Amerasian Basin Arctic Ocean

CLCS, composed of 21 scientists in fields such as geology and hydrography who are elected by member states, has accepted 24 of the 28 claims it has finished evaluating, some partially or with caveats; in several cases, it has asked for follow-up submissions with more data. Australia was the first country to succeed, adding 2.5 million square kilometers to its territory in 2008. New Zealand gained undersea territory six times larger than its terrestrial area. But CLCS only judges the merit of each individual scientific claim; it has no authority to decide boundaries when claims overlap. To do that, countries have to turn to diplomatic channels once the science is settled.

The three claims on the North Pole revolve around the Lomonosov Ridge, an underwater mountain system that runs from Ellesmere Island in Canada's Qikiqtaaluk region to the New Siberian Islands of Russia, passing the North Pole. Both countries claim the ridge is geologically connected to their continent, whereas Denmark says it is also tied to Greenland, a Danish territory. As the ridge is thought to be continental crust, the territorial extensions could be extensive. (U.S. scientists should finish mapping in the Arctic in about 2 years, says Mayer, who is involved in that effort, but as one of the few countries that hasn't ratified the Law of the Sea convention, the United States can't file an official submission.)

Tensions flared when Russia planted a titanium flag on the sea floor beneath the North Pole in 2007, after CLCS rejected its first claim, saying more data were needed. The Canadian foreign minister at the time likened the move to the land grabs of early European colonizers. Not that the North Pole has any material value: "The oil potential there is zip," says geologist Henry Dick of the Woods Hole Oceanographic Institution in Massachusetts. "The real fight is over the Amerasian Basin," Dick says (see map, above) where large amounts of oil are thought to be locked up.

It will take years, perhaps decades, for CLCS to rule on the overlapping Arctic claims. Whoever wins the scientific contest still faces a diplomatic struggle.

Denmark, Russia, and Canada have expressed their desire to settle the situation peacefully. "Russia actually has played nice on this and stopped at the North Pole," rather than extending its claim along the length of the ridge, says Philip Steinberg, a political geographer at Durham University in the United Kingdom. Denmark had no such qualms and put in a claim up to the edge of Russia's EEZ, "even though there's no way in hell they'll get that," when it comes to the diplomatic discussions, Steinberg says.

One solution would be to use the equidistance principle, by drawing a median line between the coastlines, as has been done when proposed marine territories overlapped in the past; doing so would mean the North Pole falls to Denmark. There's also a proposal to make the pole international, like Antarctica, as a sign of peace, says Oran Young, a political scientist at the University of California, Santa Barbara. "It seems a very sensible idea."