Just after noon on Sept. 4, 2010, a squat, yellow-black cargo ship lumbered out of the Norwegian port of Kirkenes. Naked ridges of glacially scarred granite slid by on either side as the Nordic Barents motored toward the open sea with 41,000 tons of iron ore locked in her belly. It might have resembled a routine voyage to Western Europe. But the sense of normalcy vanished as the ship reached the mouth of the fiord, a geographic and economic crossroads at the extreme northern edge of Scandinavia.

Rather than proceeding forward toward Europe, the Barents swung slowly to the right – to the east. The ore in its hold was destined for smelters in China. To get there, the ship would do what few others have attempted: take a shortcut over the top of Asia, through 3,000 miles of Arctic seas haunted by drifting ice. It would be escorted by a nuclear-powered icebreaker from Russia.

Similar pioneering scenes are unfolding at the planet's opposite pole, the Antarctic. Each January at the height of the austral summer, fishing vessels venture south into waters that would be impenetrable if not for an accident of nature: Upwelling ocean water a couple of degrees above freezing creates a sliver of ice-free water along the Victoria Land coast, a keyhole that the fishing boats thread on their way to the world's southernmost waters. Reaching those waters, they unfurl several miles of cable with as many as 10,000 fishhooks into the sea. Just a few years ago, the fishing vessels didn't even come here; now, the fish they catch are served in white-tablecloth restaurants in Europe, Asia, and the Americas, eaten by people unaware of their exotic origin.

The cargo and fishing vessels pushing farther north and south reflect the rapid change both poles are undergoing. Once isolated from the rest of the world, they are now the object of increasing global focus. At stake are massive untapped energy sources in the north, the world's least-fished ocean waters in the south, and precious metals turning up in places such as Greenland and Antarctica.

Global warming may have cracked open the door to the poles, but worldwide hunger for resources is prying it wider, with greater force.

"It's globalization," says Lawson Brigham, a retired US Coast Guard icebreaker captain and now professor of geography and Arctic policy at the University of Alaska Fairbanks. "Higher commodity prices will drive frontier development."

The geopolitical process that began centuries ago as the polar regions were explored continues today with countries as diverse as China, Russia, Ukraine, Britain, and Chile hovering to claim territory or resources. This maneuvering, say experts, will probably unfold without military conflict, but shaping the future of the poles will nonetheless depend on strategic assets whose importance has gone unrecognized.

Economics – not climate – opens the way

It is easy to view the increased presence of humans in the polar zones as a direct result of climate change, which has reduced the area and thickness of summer Arctic sea ice by half over the past 50 years, and continues to bleed 200 billion tons of ice from the Antarctic ice sheets each year. But sailors from European countries have been harvesting resources from the high Arctic for at least 400 years; they were driven there by factors other than climate.

The island of Spitsbergen sits 500 miles north of Norway, devoid of trees, 60 percent of its land hidden beneath glacial ice hundreds of feet thick. But by 1620, just 25 years after its discovery, English and Dutch whalers were already plying its waters, building factories on land where the blubber from butchered whales was cooked into oil and shipped back in barrels to light and fuel Europe.

Whalers were driven to Spitsbergen by a surge in the price of grain and vegetable oils in Europe, which led to increased use of whale oil as a fuel for lighting, says Dag Avango, a science and industrial historian at the Royal Institute of Technology in Stockholm who has explored the ruins of factories on Spitsbergen and studied government records. As bowhead whales near Europe were wiped out, he says, the Europeans pursued the dwindling populations north to Spitsbergen, and then farther afield to Greenland.

A similar wave of expansion into the Arctic is occurring today. Northern nations are hardly waiting for sea ice to retreat; they are already exploring areas of the Arctic Ocean rarely visited before. Some important geopolitical questions will hinge on exploration of the seafloor.

"The Arctic Ocean is very poorly mapped," says Christian Marcussen, a geophysicist with the Geological Survey of Denmark and Greenland in Copenhagen, Denmark. "If you look at the surface of the moon it's better mapped than the deep oceans."

About 22 percent of the world's undiscovered oil and gas reserves may hide beneath the Arctic seafloor, and ownership of vast swaths of it may hinge on how a handful of geographic features are interpreted. Scientists are trying to determine which areas of seafloor belong, geologically, to which continents.

In September 2007, a pair of icebreakers plowed north of Greenland through some of the world's most recalcitrant sea ice. The ships meandered to avoid places where wind had pushed the ice floes into pressure ridges as much as 50 feet thick. As the ships traveled, scientific instruments submerged below the ravages of the jostling ice blocks picked up sonic reflections from the seafloor. The instruments mapped the seafloor's ups and downs, and the thickness of mud layers draped over its bedrock.

That cruise was part of an ongoing effort by five Arctic nations (Canada, Denmark/Greenland, Norway, Russia, and the United States) to map the Arctic seafloor and claim territorial rights for oil, gas, and other resources hidden beneath it. These efforts, carried out under Article 76 of the United Nations Convention on the Law of the Sea, involve legalistic calculations of seafloor slope, depth, sediment thickness, and, in some cases, even the types of rocks on the bottom.

The 2007 cruise was mapping an undersea rise called the Lomonosov Ridge, which stands as tall as the Alps and spans the Arctic Ocean from Greenland to Russia. Rocks dredged up from the ridge suggest it is several hundred million years older than the surrounding seafloor – suggesting that it represents a fragment of crust torn from the edge of one continent or another. That's why Canada, Greenland, and Russia each claim that the ridge represents an extension of their own continental shelf.

The stakes are high. If you lay claim to the Lomonosov Ridge, says Dr. Marcussen, "you can extend your claim all the way to the North Pole." (The three countries will submit their competing claims to an international commission within several years.)

It's easy to imagine that such dueling claims could trigger military tension. After all, the resource rushes to Spitsbergen were punctuated by geopolitical conflict: Whalers from competing countries demolished each other's factories. But Dr. Avango distills a different insight from 400 years of history. He points out that when conflicts erupted in Spitsbergen, they were quickly settled: English and Dutch whalers agreed to divide the island.

The current Arctic scramble "is not a move toward conflict," concludes Avango. Instead, it is "leading to a greater will from the competitors there to come to agreement and draw borders as soon as possible so that they can go on and make some money."

In one recent example, a decades-long boundary dispute between Norway and Russia in the Barents Sea was finally settled in 2010 – just as energy companies were exploring the area for oil and gas.

Russia has also opened its long-guarded Northern Sea Route (NSR), lowering its fees to encourage international traffic and turn the route into a moneymaker. This, more than any reduction in sea ice, was what set the stage for the cross-Arctic transit by the Nordic Barents in 2010, says Jon Edvard Sundnes, chief executive officer of Tschudi Shipping Company in Oslo, which spearheaded the voyage.

When the Barents finally unloaded its ore in Lianyungang, China, it had shortened its voyage by 5,500 miles and 16 days compared with the standard route through the Mediterranean Sea and Suez Canal. Use of the NSR has expanded since then: 46 ships crossed in 2012, and at least 60 did so in 2013.

Contrary to public perception, the NSR won't become a superhighway anytime soon for teddy bears, blenders, or anything else carried in shipping containers. Large container ships reinforced against ice aren't available. Traffic on the frontier route has included iron ore, coal, and phosphorus minerals used to make fertilizer – materials mined in northern Norway, Sweden, or Russia, and consumed in China, Japan, or South Korea. Liquefied natural gas is also traveling in tankers across the NSR: Lower gas prices in the US, due to shale gas extraction, have pushed European companies toward using the route to deliver their gas to Asia, where it can net five times the price in the US.

"We are speaking about shipping companies availing themselves of short-term opportunities," says Arild Moe, who studies Arctic and Russian commerce at the Fridtjof Nansen Institute in Lysaker, Norway. Whether or not the NSR becomes a mainstay of world shipping will depend on Russia funding improvements: producing better maps of its notoriously shallow seafloor; building deep-water ports so larger, more cost-effective ships can pass through; and maintaining its dwindling fleet of half a dozen nuclear-powered icebreakers. Doing this may serve Russia's strategic interests by improving its ability to export its own raw materials.

"If you look at the northern region there are enormous resources of minerals," says Mr. Sundnes. "But logistics and export has been an issue." Russia maintains the world's largest nickel mine at the Arctic city of Norilsk. And then, of course, there is oil and natural gas.

Last month, the Russian company Gazprom began oil production from the world's first offshore Arctic drilling project. The site, called Prirazlomnoye, is modest, consisting of one drilling platform situated in just 60 feet of water in the Barents Sea, in some of the mildest Arctic waters. But it was a major undertaking. The platform amounts to a fortress, strengthened against ice, sitting directly on the seafloor.

While Russia and Norway continue to explore the Barents Sea, Dr. Moe doesn't expect any other offshore drilling in Alaska, Canada, or Greenland to begin production before 2020. Even onshore Arctic drilling will require massive investment. A liquefied natural gas project planned for Russia's remote northern Yamal Peninsula will use 16 tankers to ferry gas across the NSR – each ship an icebreaker unto itself, able to plow through five feet of ice at 5 miles per hour, burning more than $10,000 of fuel per day.

All of this speaks to a simple truth, says Dr. Brigham: "There are tremendous opportunities to link the Arctic to world markets." He suspects that even commodities like fresh water stored in Arctic lakes and glaciers could eventually find buyers around the globe.

And contrary to themes expressed in the media, this push into the Arctic is being driven at least as much by global demand and depletion of resources closer to home as by climate change or loss of sea ice.

Antarctica differs vastly from the Arctic. The Arctic consists largely of a sea covered by ice that averages six feet thick, fringed by the northernmost territories of three continents; the Antarctic consists of a lone continent isolated by a ring of turbulent seas. While Arctic sea ice is disappearing quickly, the continent of Antarctica is 98 percent covered by glacial ice thousands of feet thick; it contains most of the world's fresh water. Even as Antarctica sheds 200 billion tons of ice per year, contributing to sea-level rise, the immediate effect on human activity there is negligible.

Despite these differences, similar economic and political forces are converging on Antarctica. The signs are obvious at its closest geographic gateway, the tip of South America.

The South Pole Monopoly game

An hour south of Punta Arenas, Chile, a blue sign stands alongside the coastal road. That sign says, "CENTRO GEOGRAFICO DEL PAIS" – marking the north-south midpoint of Chile. Never mind that it sits on the southernmost road of the South American mainland, just a few miles short of where the pavement dwindles to a strip of tire-rutted beach sand. Never mind that the continent itself ends just 180 miles farther south in a series of forlorn stone pinnacles battered by the waves.

That sign makes sense only if you consider one key fact: It counts a large pie-slice of Antarctica as Chilean territory, stretching from the tip of the Antarctic Peninsula, all the way to the South Pole. Maps on the walls of schools and libraries throughout Chile show this bicontinental version of the nation's geography. TV weather forecasts even report temperatures at Chilean research stations in Antarctica, and the TV weatherman gestures at maps showing storm fronts rolling over not only the South American mainland, but also the Antarctic Peninsula.

Chile's claims in Antarctica date back to World War II, and to whaling and fishing expeditions that go back to the early 1900s. Chile even maintains a perfunctory settlement in Antarctica, the town of Villa Las Estrellas on King George Island, where children as young as 6 are taught in a corrugated metal schoolhouse.

All of this "is about reminding Chilean citizens but also the wider world that they consider this to be national territory," says Klaus Dodds, a political geographer at Royal Holloway, University of London.

Most interesting of all, this same slice of Antarctica is also claimed by two other countries – Argentina (which makes all of the same symbolic gestures that Chile does) and Britain.

The Argentines see their claims in Antarctica on par with their claim of the British-controlled Falkland Islands, which prompted them to invade the islands in 1982. Britain may hold onto the Falklands so staunchly in part, says Dr. Dodds, because they provide a strategic gateway to British claims in Antarctica.

These latent disagreements hide beneath a veneer of harmony. The southern continent has been governed since 1961 by the Antarctic Treaty, a creation of the cold war, intended to prevent US-Soviet tensions from spilling into the region. The treaty enforces environmental regulations, allows nations to inspect each other's bases, and requires sharing of scientific data. It started with 12 nations, but now includes 28.

Just as people playing the board game Monopoly profit by building a house on Park Place or Boardwalk, countries building a station and conducting research in Antarctica can obtain treaty membership and influence.

"That motivates a lot of these countries to build a research station there and to fund some kind of scientific research," says Avango. "It is about being a part of a larger international community that can make decisions about the future of Antarctica."

This includes decisions about how and when Antarctica's natural resources should be harvested. For the moment, this includes only fishing in the ocean waters around the continent. Antarctic krill have been fished for decades; they're used in commercial fish feeds and omega-3 fatty acid dietary supplements.

But fishermen have recently begun venturing south in search of another species – and this has elicited controversy.

The 'sea bass' euphemism

In 1977 an American businessman began importing a new fish from South America to the US: a monstrosity with leathery lips and a mouth evolved for sucking up prey in the blink of an eye – the kind of looks you'd expect of a fish that lurks in the dark, as deep as 13,000 feet. Slicing the fish into skinless fillets relieved it of its appearance, and the businessman erased its last vestige of ugliness by changing its name from Patagonian toothfish to Chilean sea bass.

The fish was a hit in restaurants, prompting fishermen to look for it in other places. Their attention eventually turned to a closely related species, the Antarctic toothfish, which inhabits the world's southernmost waters. Commercial harvesting of Antarctic toothfish began in 1996, in Antarctica's Ross Sea.

Vessels fishing for toothfish carry scientific observers and are tracked by GPS; and a few fish are tagged and released in order to monitor the population. All this makes it "one of the best managed, most sustainable, environmentally benign fisheries in the world," says Martin Exel, a senior manager at Austral Fisheries, a company based in Perth, Australia, that fishes for toothfish.

But Arthur Devries, a marine biologist at the University of Illinois in Urbana, sees another story unfolding. In dozens of visits since the 1970s to McMurdo Station, the main US base, he has studied toothfish in the Ross Sea. Each day while there, he rode a snowmobile several miles out onto the sea ice covering McMurdo Sound. He fired up a winch and hauled 1,500 feet of cable and fishhooks up through a hole in the ice. He often found a dozen toothfish snagged on the hooks; he tagged and released most of them.

"We could catch them in great numbers and did so for 30 years," he says – but no longer. Dr. Devries caught not a single fish in the summer of 2006. He and his students have caught only a couple dozen toothfish since then – less than a tenth of their previous catch – and the fish are smaller. "The fishing industry must be taking enough of the population so that they don't come into McMurdo Sound in the numbers they used to," he says.

The current health or peril of the Antarctic toothfish population remains unresolved. So does the fundamental question of how much the world's most pristine waters should be fished, period, and that is becoming a political problem. In November, a proposal to set aside 500,000 square miles more of the Ross Sea as an unfished preserve was vetoed by Russia, Ukraine, and China.

Telltale signs suggest that the southern continent holds other resources, whose discovery could pose difficult political questions.

Glint of gold lures a helicopter to land

Laura Crispini first glimpsed one of those signs out the window of a helicopter passing low over the Bowers Mountains in Antarctica on Dec. 8, 2005. The helo was following a ridge of greenish rock rising above the glaciers when she spotted a band of yellow-white stone slicing across it.

Dr. Crispini, a geologist from the University of Genoa in Italy, had come here to map tectonic faults – but the discovery of this particular fault would have implications beyond basic science. She asked the pilot to land, and she scrambled with a co-worker down the ridge, past bands of white quartz and iron-rich carbonates many feet across. Near the center of the white zone she saw a metallic glint in the rock: narrow, stringy veins of gold, pure and soft enough to dint with her pocketknife.

The veins had formed millions of years before as superheated water and carbon dioxide, from thousands of feet below, spurted up like espresso through cracks, leaching trace amounts of gold from the stone along the way. The fluids cooled as they rose, and the gold that had accumulated in them coalesced into metallic crystals.

Antarctica may hold plenty of mineral resources. Three hundred million years ago, it lay at the center of a supercontinent, Gondwana, which also included South America, Africa, Australia, and New Zealand. Folding of Earth's crust caused plumes of magma and superheated fluids to rise, concentrating minerals near the surface of Gondwana: copper, tin, silver, lead, and zinc along what are now the South American Andes; and gold, copper, lead, zinc, nickel, and cobalt in southeastern Australia.

"Just by extrapolating, you might expect that Antarctica should have geology similar to those other continental areas," says John Goodge, a tectonic geologist at the University of Minnesota Duluth. He and others have reconstructed the jigsaw puzzle of Gondwana to identify where these same mineral-rich belts cut through Antarctica.

Harsh climate and ice cover pose extreme barriers to profitable mining in Antarctica, but this hasn't stopped the topic from coming up. In the 1980s a group of nations including the US and Russia sought to negotiate a framework within the Antarctic Treaty that would permit drilling and mining. But it was vetoed by France and Australia, and a ban on mining and drilling was adopted in 1991; it runs through 2048. But that may not be the end of it.

"The question of mineral exploitation hasn't gone away in Antarctica," says Anne-Marie Brady, a specialist in polar politics at the Woodrow Wilson International Center for Scholars in Washington, D.C.

As the Antarctic Treaty has grown in recent decades, some nations eager to join it and build bases in Antarctica appear to have long-term interest in the continent's mineral and energy resources. A number of countries fall equally within this category, including Russia, Ukraine, Belarus, China, Korea, and India – but as a Mandarin speaker, Ms. Brady has performed an especially large number of interviews and reviews of government documents in China. "The mainstream point of view" in China, she says, "is that it's only a matter of time that Antarctic minerals and energy resources will be exploited."

Conditions in Antarctica will be tough, but rising commodity prices and improving technology may eventually make it worthwhile, says Brady: "People whom I've talked to in China about this issue, they're confident that the technology will be worked out."

These discussions of resources fly beneath the radar, confined to a country's native language, but signs surface now and then. For example, there were reports published in 2013 by Ukrainian scientists prospecting for offshore natural gas in Antarctica. If minerals or hydrocarbons are harvested even decades from now, the land claims, human settlements, and symbolism employed by countries like Argentina and Chile will make sense. "It builds up arguments for a future that the Antarctic Treaty will be renegotiated," Avango says of a time when territory claims that the treaty put in limbo could well be revived.

The US has no territorial claim in Antarctica but maintains the right to make one in the future – and has by far the largest research footprint there: McMurdo Station alone houses 20 percent of the continent's 4,400 summer inhabitants. McMurdo is nourished by a tenuous lifeline: Two ships each summer deliver 7 million gallons of fuel and 10 million pounds of food and supplies. The ships could never make it if not for an icebreaker that clears a path through six feet of sea ice choking McMurdo Sound. But from 2006 to 2013, the US possessed only two functional icebreakers – forcing it to hire vessels from Sweden and Russia for this vital task. And in October, the US Antarctic Program faced an undignifying setback as the government shutdown disrupted cargo flights and summer preparations at McMurdo – canceling or postponing research projects that had been planned for half a decade.

Get the Monitor Stories you care about delivered to your inbox. By signing up, you agree to our Privacy Policy

Every nation that hopes to play a role in shaping the future of the poles – whether for exploitation, territory, or conservation – will require certain strategic assets: scientific research that maintains prestige and expertise; well-placed ports, airfields, and research bases in the polar regions; experience landing and launching large military cargo planes on glacial ice; and, of course, icebreakers. Negotiating a future for the poles will take decades, beyond the oft-shortsighted view of politics, elections, and funding cycles. But the outcome of that process could be profound, influencing the world's political, economic, and environmental order for a century to come.

• Douglas Fox is a northern California based science and environmental writer whose work has appeared in the annual anthology "The Best American Science and Nature Writing," as well as in the Monitor, National Geographic, Nature, and Scientific American. His last trip to Antarctica – a two-month expedition in 2013 with scientists looking for life in subglacial Lake Whillans – was funded by the National Science Foundation.