Five years ago, after Mininnguaq Kleist became Greenland's national badminton champion but before he took the helm at the Office of Self-Governance, he discovered secession theory: the study of whether one country has, or doesn't have, the moral right to break free from another. "I found arguments that are never used up here," he says. Over the following year he wrote his thesis, "Greenlandic Auto- nomy or Secession: Philosophical Considerations", at his university in Denmark, the colonial power that has ruled Greenland for nearly 300 years. The 35-year-old, whom friends call Minik, wrote it in Danish, and he pushed arguments that challenge the colonisers using their own rules, even as they ran slightly counter to those laid out in the 1990s by the father of modern secession theory, philosopher Allen Buchanan.

"According to him, you have to be wronged to justify it," says Minik. "Denmark has to wrong Greenland in a really bad way before we break away. I don't agree with that part. Sometimes you have to view this as a marriage: adults, consenting people, divorcing of their own free will."

To its Inuit natives, Greenland now officially goes by the name Kalaallit Nunaat – "Land of the People". As a colony, it has been part of Denmark since 1721, when Lutheran missionary Hans Egede showed up and started saving souls. The first Danes taught the Inuit that Hell was very hot rather than very cold. They taught that communal living – shared food, shared hunting trips, shared wives – was sinful. They taught that rocks and birds were not endowed with spirits. Greenlanders had no bread or concept of bread, so Egede translated another pillar of Western belief – the Lord's Prayer – to fit Greenlandic reality. "Give us this day our daily harbour seal," they prayed.

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I first meet up with Minik in the Kangerlussuaq airport, a building on the tundra of western Greenland that feels like a ski lodge in the Alps: lounge chairs, huge windows, a cafeteria with trays, rich tourists in Gore-Tex. Minik is heading up the west-central coast to Upernavik, a 1,000-person town with no sewage system, where, several mornings a week, the streets are lined with yellow bags of excrement waiting to be picked up by sanitation teams.

Upernavik is the first stop on the second leg of a road show led by the Office of Self-Governance, a department local authorities set up at the end of 2007 to bring independence – or at least the idea of it – to the people. It is now early September 2008, and by 25 November, he wants to have reached nearly all of Greenland: 57,000 people spread out across 57 villages and 18 towns and an area of 836,000 square miles, 16 times the size of England and 50 times the size of mainland Denmark; 25 November is the date of an island-wide vote, a referendum on divorce from Denmark. If it was to pass, then on 21 June 2009, the summer solstice, Greenland would wake up to a new reality. Not secession, exactly, but a big step in that direction.

Global warming is melting Greenland's ice, extending its shipping season and revealing massive oil and mineral deposits. This is making possible a mining boom and the royalties that go with it, which in turn is convincing Greenland's people that eventually they may not need the £370m in annual subsidies they get from Denmark—more than £6,000 a person. Which itself is convincing Greenlanders that soon they may not need Denmark at all.

Climate change means oil finds and zinc mines and also better fishing: cod, herring, halibut and haddock migrating north as the ocean warms. It means disaster tourists: people coming to see glaciers slide into the sea. (Since 2004, cruise-ship arrivals have jumped 250 per cent.) It means farming: potatoes and broccoli and carrots growing where they didn't grow before, more grass for more sheep. And it means gushing rivers: an endless supply of freshwater that Greenland proposes to sell to a thirsty world.

It also means doom for distant countries such as Tuvalu, in the Pacific Ocean, and Bangladesh, which may go under because of Greenland's melting ice cap. The cap covers 81 per cent of the island, and if it melts entirely—something that is unlikely to happen before the end of this century—global sea levels could jump 20 feet. Since 2003, the cap has shrunk by more than a million tons – so much that the underlying bedrock rises 4cm each year, like a ship slowly unweighted of its cargo. The land is rising faster than the sea.

It is climate's role in the independence movement – the possibility that people could be set free by embracing a crisis, that for all the countries destroyed by global warming, one will be created – that has brought me to Kangerlussuaq. Before we board our next flight, Minik introduces me to a pack of half-a-dozen Greenlandic politicians who are part of his revolutionary road trip. They wear backpacks and street clothes: jeans, fleeces, tennis shoes. One man carries a video camera. I wonder, for a moment, whether I'm staring at people for whom global warming serves a higher good.

The first meeting takes place inside the community sports hall in Upernavik, and its high point is a funny story about a whale. It is told by Jens B Frederiksen, the leader of the Democrats, the only one of Greenland's four major ' political parties arguing for a "no" vote in November. Frederiksen was a policeman here in the 1990s, and the story goes like this: The police chief gets a call from a citizen. The citizen is a fisherman. He has caught a whale. He doesn't know what he should do with this whale. The chief says to the citizen, "Put it in the boat. We'll take care of it tomorrow."

Put it in the boat! Take care of it tomorrow! The crowd, roughly 60 people, roars with laughter.

Frederiksen's party has the support of many ethnic Danes, who make up 10 to 15 per cent of the Greenlandic population, but it is still one of the island's smallest. Earlier this afternoon, the politician and I walked around Upernavik—past an unmarked liquor store, past wooden houses painted in beautiful primary colours—while he explained his party's unpopular stance.

"We want self-governance, too, but we don't have the economy right now to go forward," he said. He ticked off the basic services that Greenland hopes to take over: policing, education, immigration, mining, courts. Thirty-two areas in all. This will require money—if not Denmark's, somebody else's.

"Yes, we want oil," Frederiksen continued. "We will jump and be happy when we find oil. I also really hope to win the lottery but I can't count on it." His argument isn't about nationhood. It's all about the numbers – pure economics – and that may be why hardly anyone is listening. Even nationalists agree, however, that as colonisers go, Denmark isn't bad. In Canada, the Inuit were given numbered, dog-tag-like IDs because they had no surnames, and they were moved to barren islands to reinforce sovereignty claims. But in the Danish colony, the crown declared as early as 1782 that the Greenlanders' welfare should "receive the highest possible consideration, [overriding] when necessary the interests of trade itself". Denmark established paternalistic rules about alcohol and intermarriage, and even its most controversial programme – an effort in the 1960s to move families from traditional villages to centres such as Upernavik, where services could be concentrated – was meant to improve lives.

In the Upernavik sports hall, we are at nearly 73 degrees north. The small town is seasonally frozen out of all ship traffic, sits on tree-less tundra 600 miles from the capital, and yet has this: a hospital staffed by Swedes and Danes, a price-subsidised Pisiffik supermarket, a strong mobile-phone signal, and paved streets. This is what the Danes did. They harvested whales and fish and some coal, but they gave back homes and schools and hospitals. In 1953, they gave full Danish citizenship to every Greenlander. They gave students such as Minik a free education at the university of their choice in Europe or North America. And they did it all with the smug certainty that Greenland could never manage on its own.

Up for a vote on 25 November is "self-governance"– namminersorneq in Greenlandic, selvstyre in Danish. Though not full independence, it is far closer than the limited home-rule system in place since 1979, which gave Greenland authority over a handful of government ministries. As agreed to in principle by Danish prime minister Anders Fogh Rasmussen and Greenlandic premier Hans Enoksen, Greenlanders will have a recognised right to self-determination. They will take over responsibility for almost everything but foreign affairs and defence. At first they'll keep the £370m annual grant from Denmark, but as petroleum and other mineral revenues go up and up, the grant will go down and down, until it hits zero. Greenland can secede any time along the way. It could take decades.

While Frederiksen talks, Minik grimaces. He is standing alone in the back of the hall, near a table with coffee and tea and crumble cake. "Remember this," Frederiksen says to his audience: "The Democrats did not say 'no' to self- governance. We just said 'no' to this agreement." When Kuupik Kleist, the popular leader of the leftist, pro- independence Inuit Brotherhood, speaks in favour of self-governance, Minik allows himself a smile.

"We would like to take care of ourselves," the politician says in his booming voice, and everyone claps. "If we want to reach something, we should be ready to sacrifice something." This idea – that Greenland may suffer after it takes over but that a little suffering is worth it – isn't one that every leader will voice out loud. Now only Minik is clapping.

It did not take long for me to hear what those sacrifices might be, on a helicopter trip with GEUS, the Danish geological survey. The GEUS scientists were retrieving a broken instrument on the ice cap two hours' flight north of Upernavik, and along for a free ride were me and a Dane called Nikolaj, a lab technician at the Upernavik hospital. He and the pilot also co-own a kayaking business that rents out boats, drybags, satellite phones, and polar-bear protection in the form of rifles. The doctors are all foreigners, he says. "They come for one month at a time. It's like a vacation for them." I ask what he thinks about the referendum. "People here are spoiled," he says. "They don't give a shit. They have no idea how much things really cost. Housing. Boats. Fishing. Everything. They don't understand that, without support, it could never be."

Premier Hans Enoksen catches up with us on the way to Uummannaq, a 1,300-person island town that is famous here as the home of Siissisoq, a metal band that sings in Greenlandic about the slaughter of African mammals. The next afternoon, I watch the premier take part in a four- on-one verbal battering of Jens B Frederiksen inside a firehouse-red high school. Enoksen is stern and primal, slowly pumping his fist in the air as he speaks.

The leader of Siumut, the party in charge of the home-rule government since it began in 1979, Enoksen is a former town grocer who was elected in 2002 after serving as Minister for Fisheries, Hunting, and Settlements. He is the first premier who wasn't educated in Denmark, who doesn't speak Danish or English. In Nuuk, a rival minister is challenging him for leadership of Siumut, and some of his appointees are facing a corruption scandal. But in the villages, he is loved. Every summer, he pilots his fishing boat alone up the coast, checking in on community after community. He wants self-governance to be his legacy. Enoksen hires a blue powerboat the next day, and we head off to visit villagers. After a while he turns to me. "The American ambassador in Copenhagen has been very supportive of self-governance," he says, Minik translating. "Much more than any before him."

I tell him I am not surprised. In 1946, the American government was so impressed with Greenland's strategic potential that it secretly tried to buy the island from Denmark for $100m. The US military still runs Thule Air Base, a Cold War-era installation in Greenland's far north. Now that we have learnt Greenland has a lot of oil, US companies are buying up exploration blocks near Disko Bay, about 100 miles southwest of us.

For Greenland, doesn't independence from Denmark simply mean dependence on foreign corporations? Enoksen has heard it before. "If oil is discovered, foreigners will come no matter what," he says. "But after we vote 'yes', they will be working for us." He pounds his fist against his chest three times, then raises it to the sky. "This is what will change under me," he says.

To visit one of the sites that will fund Greenland's future, the Black Angel zinc mine, I again motor out of the Uummannaq harbour, into the same broad channel, but this time the boat captain is Danish, and he is working for the British. We leave the channel and cross a choppy stretch of open water, then hug another set of cliffs. We enter a long fjord, where we wave at fishermen and slow down to watch a village woman butcher a seal on a rock. Two hours after leaving Uummannaq, the namesake Angel rises before us: a Rorschach blot of ghostly black zinc, 2,000ft up, on the side of a mostly white cliff. I have wanted to see Black Angel since I heard about it at the first annual Greenland Sustainable Mineral and Petroleum Development Conference, which was held in May 2008 at a Radisson Hotel in Copenhagen. The mine's owners, the British firm Angus & Ross, hadn't tried to hide the fact that they were profiting off global warming, which caught my attention. Otherwise, the conference had been discussing Greenland's tough logistics and "world-class commercial terms". If you could get there, the speakers said, Greenlanders would let you drill anywhere.

There was a presenter from Alcoa, which plans to dam two west Greenland rivers and build one of the world's largest aluminum smelters—340,000 tons a year. There was a GEUS presentation about Greenland's petroleum prospects: on the west coast, eight oil leases were just sold off to companies including Chevron, Exxon, Canada's Husky Energy, and Denmark's DONG Energy. On the east coast awaited the 19th-richest of the world's 500 known petroleum provinces: an untapped Gulf of Mexico in the North Atlantic.

Angus & Ross chief executive Nick Hall showed photographs of Black Angel and explained its history. The zinc deposit, one of the richest on the planet, was discovered in the 1930s, explored in the 1960s, and mined between 1973 and 1990 via tunnels dug near the Angel high above the fjord, reached by cable car. Then it was abandoned. His company took over the lease in 2003, when zinc prices were about to rise, and in 2006 two geologists on a day hike discovered a deposit as pure as the original at the edge of the retreating South Lakes Glacier. Until now it had been hidden by a wall of ice. Along with the extended shipping season, it was, Hall admitted, the "upside of global warming".

When I arrive at Black Angel, the mining camp is nearly empty. It is the end of the summer work season, the beginning of a global recession, and credit is drying up while zinc prices are falling. Australian Tim Daffern, my host, quit a successful consulting job to run operations at the mine – and now he is hanging on by a thread. Black Angel will bounce back in January 2009, and in April Angus & Ross will even expand its holdings to include the Nalunaq gold mine, in Greenland's far south. But at the moment I am witnessing the danger, for Daffern and for Greenland, of betting everything on the commodities market.

The camp is a series of prefab buildings on a man-made plateau, surrounded by the crumbling concrete and rusting machines of the original operation. Next to the harbour sits the cabin of a cable car that will span the mile-wide fjord to reach the mine. The buildings contain bunk rooms and a lounge with couches, a widescreen TV and a Wi-Fi connection. Inside the lounge, Daffern tells me his company's game plan. They will start with the two tons of zinc left in the original mine: the support pillars, mainly, which they will replace with cement columns. "That's enough for five years of mining," he says. Next they will focus on the deposit at South Lakes Glacier, which is certain to keep retreating – they commissioned a study by GEUS and some British scientists to be extra sure. South Lakes will buy them another decade. A third deposit could buy two more years; a fourth, three more – glaciers shrinking all the while. "Anywhere the ice retreats," Daffern says, "we'll explore."

Daffern's predecessors dumped their tailings in the fjord. The waste was 0.2 per cent lead, 1 per cent zinc. Every spring, a rush of melting water spread the waste farther. It was ingested by blue mussels, and fish ate the mussels, and seals ate the fish, and on it went up the food chain. After 17 years of mining, it took another 17 years for the fjord to recover. The home-rule government has toughened regulations and Daffern promises to do things differently. He also promises, just as everyone did at the mining conference, to hire as many locals as possible.

On day seven of the tour, after seven meetings in seven villages and towns, the politicians relax in a government guesthouse outside the Qaarsut airport, waiting to go home. Then the premier walks in and announces that a hunter's boat is ready to take us on a quick visit to the village of Niaqornat, population 68, more than an hour up the Nuussuaq peninsula. Going out again is masochism. Only Minik and I agree to join him.

The open boat is maybe 15ft long. Minik and I keep low out of the biting wind, but the premier, wearing jeans, thin gloves and a baseball cap, stands in the back of the boat, watching the coastline zip by.

The village is stunning, on a spit of low-lying land between an oceanside turret of rock and the white peaks of the peninsula. There are bright wooden houses but no cars. There are racks where villagers are drying junk fish for the sled dogs and strips of halibut and seal for themselves. Open boats and icebergs share the harbour. The sun is shining. It is, for once, the Greenland of my imagination – and perhaps that of the premier's as well.

The meeting is held in the schoolhouse, and a quarter of Niaqornat shows up, if you count the baby. As the premier talks, I check out a poster showing eight local whale species and their specs: weight, top speed, length, amount of time they can hold their breath. A man in a T-shirt that reads "Deep Sea Shark Fishing" asks about money, and Minik flips through some slides I haven't seen before: projections of mineral revenues skyrocketing into the future. One shows the oil blocks that Greenland has already sold to foreign firms. They're on just the other side of the peninsula.

A few months from now, Niaqornat will become one of a handful of villages to vote 100 per cent in favour of self- governance. The referendum will pass by 75.5 per cent across Greenland, but in tiny Niaqornat, there will be no doubters. Just in time for the solstice, at the start of this new era, the premier will lose his job to Kuupik Kleist. This will only accelerate the drive toward independence: Kleist's party wants it all the more, and even his partner in the new governing coalition, Jens B Frederiksen, will be stirred to patriotism.

"We have one goal," he tells reporters. "The ultimate independence of our country."

We're in Ilulissat, Greenland's big tourist town, where we have a final layover. Nearby is the fastest-sliding glacier in the northern hemisphere, Sermeq Kujalleq, which spits 35 trillion litres of ice into Disko Bay every year.

I spend the early evening on the boardwalk of the Hotel Arctic, a cliffside landmark that happens to be hosting the Nordic Council's Common Concern for the Arctic conference, European dignitaries in nice suits fretting abstractly about the warming north. Peering into a bay full of icebergs at sunset, I hear one of them chat up an attractive blonde by rattling off facts about the coming doomsday. His tone is solemn, his voice almost a whisper. "I don't mean to scare you," he murmurs. It's the first time I've heard someone try to use climate change to get someone else into bed. "I really don't mean to scare you," he says again. She doesn't look scared at all. Upstairs, Minik and I order hamburgers and stare at the lights of Ilulissat. "It's so strange," Minik says. "The more the ice cap melts, the more Greenland will rise. These other countries are sinking, and Greenland is rising. It is literally rising." Below us, the dignitaries file into their banquet. "We know Black Angel was really bad for the environment the first time," Minik continues. "It ruined the fjord. Is it OK to ruin three or four fjords in order to build the country? I hate to even think this, but we have a lot of fjords."

He shakes his head. "We're very aware that we'll cause more climate change by drilling for oil," he says. "But should we not when it can buy us our independence?" I look at him. I can see he doesn't really know the answer either.

A longer version of this article appeared in 'Outside' magazine. For more information, outside.away.com