Donald Trump wants to own the world's biggest island. Why?

Why is it called Greenland?
The name was coined by the Norse explorer Erik the Red. Exiled from Iceland for murder, he landed there in around 982 and settled there a few years later. He chose the name to encourage other settlers, though it was misleading: the Greenland ice sheet, the world's second-largest body of ice, is more than twice the size of Texas, and covers about 80% of the island. Conditions were more clement in Erik's time, but not by much: the Norse settlements eventually collapsed in the mid-15th century, predominantly because of a cooling climate. The island had also been settled by Inuit people migrating from North America, the most recent migration beginning around 1100. Today, its population of 57,000, concentrated largely around the capital Nuuk, is nearly 90% Inuit or part-Inuit; the remaining 11% is largely from Denmark, which retains sovereignty over it.

How did Denmark come to own Greenland?
The Danish-Norwegian kingdom claimed it as a colony in the 1700s, and Denmark took full ownership in 1814, when the kingdoms split after the Napoleonic wars. After the Second World War, during which it was a de facto protectorate of the US, Greenland ceased to be a colony, becoming a province of Denmark in 1953. Danish became the national language, and the population was "Danized": encouraged to abandon their subsistence lifestyle, and to live in modern homes built by the state. Danish officials regarded this as a philanthropic attempt to modernise Greenland, but they left a legacy of grievance. Some Greenlanders were forcibly relocated; so-called "experiment children" were sent to be fostered in Denmark to see if they could be turned into "little Danes". In 2017, reports emerged that healthcare workers in the 1960s and 1970s fitted about 4,500 Inuit women and girls with IUDs, in a secretive attempt to reduce births out of wedlock.

What is Greenland's political situation today?
In 1979, Greenlanders voted for home rule, not least because they wanted to withdraw from the EEC, which was encroaching on fishing rights; Greenland withdrew in 1985. Following a referendum in 2008, it assumed self-governance on all domestic matters. Today, Greenland defers to Copenhagen only in foreign policy and defence, though Denmark retains a percentage of mineral exports. Even so, polls suggest about 84% of Greenlanders support independence, along with four of the five major political parties. Greenland could hold a referendum at any time, but has not done so. It is heavily financially dependent on Denmark: the "block grant" subsidy was last year worth £480 million, making up about two-thirds of all state spending.

Where does the US come in?
America has tried in the past to gain control of Greenland. It considered a bid for ownership in 1867, following the acquisition of Alaska from Russia. In 1910, a proposal was made involving swapping land in the Philippines, but no agreement was reached. In 1941, the Danish ambassador to Washington (Denmark itself was Nazi-occupied) authorised the US military to build an outpost. Weather forecasting stations, as well as mines extracting the mineral cryolite (indispensable for aircraft production), were also established. After the war, the US government offered to buy Greenland from Denmark for $100 million, but was rebuffed. During the Cold War, Greenland's position between Russia and the US became strategically important, and a 1951 treaty allowed the US to keep military bases on the island. In 1953, the Thule Air Base (now Pituffik Space Base) was built as the US's northernmost military outpost.

Why does Trump want Greenland?
He says it would be "strategically nice". The island lies on or near the likely ballistic missile routes from Russia to the US; America relies on missile-tracking facilities there. In a world war, controlling the so-called "Greenland-Iceland-UK Gap" in the North Atlantic would be crucial. For now, Russia is the primary Arctic power, while China also has "near-Arctic" ambitions. In addition, Trump says the US needs Greenland for "economic security". Some think that, as the ice thins in the Arctic, new shipping routes will open up. He is known, too, to be much concerned with mineral resources, and Greenland is rich in uranium, and rare earth minerals used in green tech. However, there are real doubts about how practical any of this is. Mining in the Arctic is hard; various Chinese projects in Greenland have been abandoned. Besides, Denmark and Greenland have always facilitated the US' military and commercial objectives. One big draw for Trump may be that Greenland is so large – the world's biggest island, more than 836,000 square miles – and thus an exciting piece of "real estate".

What is the Danish response?
Trump's first attempt to buy it was in his first term. Both Denmark and the Greenlandic government rejected the 2019 proposal, saying: "Greenland is not for sale." Copenhagen has retained that position, in the face of somewhat ominous statements from Trump; there was a reportedly fiery phone call between him and the Danish PM Mette Frederiksen in January. He has refused to rule out military action. "I think we're going to get it one way or another," the president said in his speech to Congress earlier this month. What do Greenlanders think? After elections this month, the five main parties united to describe Trump's aim of annexing Greenland as "unacceptable"; polls suggest 85% of its people agree. Jens Frederik Nielsen, leader of the centre-right Democrats (the biggest party) and the likely next PM, said: "We don't want to be Americans. No, we don't want to be Danes. We want to be Greenlanders." The Democrats' goal is to make Greenland more self-sufficient, and only then to seek independence. That could mean deeper economic ties with the US.

Life in the far north
Greenland is the most sparsely populated territory on Earth. All of the largest settlements are on the coast, and there are few roads inland. Each year, it enjoys perpetual daylight for around two months, and perpetual night for almost three months. In winter, the capital Nuuk in the south sees average temperatures of only –8C, because it is warmed by the Gulf Stream. By contrast, in the north, average temperatures are around –18C. In central Greenland, temperatures nearing –70C have been recorded. In summer, temperatures seldom reach above 10C; this is too cold to sustain trees, so the land is largely a treeless tundra. Agriculture is only possible in the sheltered fjords in the south of the country, where people keep some livestock and grow vegetables. Greenland has a super-charged version of the Nordic welfare model; the state employs about 40% of the workforce (compared with about 18% in the UK). Fishing is the biggest industry, employing some 4,300. Only one mine is now in operation, in western Greenland; mining in the far north is difficult due to weather and shipping conditions, and the lack of local workers. Alcoholism is prevalent; the WHO describes it as "a long-running public health challenge".

It's a "dismal parable" of Broken Britain, said Andrew Neil in the Daily Mail. Last Thursday, one creaky old substation near Heathrow managed to bring Britain's busiest airport to a shuddering halt for 24 hours, when an explosion in one of its transformers started a fire; more than 1,300 flights were cancelled, leaving hundreds of thousands of passengers stranded. This wasn't just a "massive inconvenience"; it was a "global embarrassment". Why was Heathrow so dependent on a single substation? Why did it have no adequate standby source of power? Back-up generators kept the airfield lights on, but passengers were forced to use their phone torches to navigate the pitch-black terminals, while baggage carousels came to a shuddering halt. The disruption was so great, said Quentin Letts in the same paper, that people initially assumed Vladimir Putin was behind it – but officials have ruled out foul play. Who needs Russian sabotage "when good, old-fashioned British bodging" can "do the job for you?"

Oh, come on – it wasn't as bad as all that, said Libby Purves in The Times. In fact, given the potential scale of the chaos, I think our national infrastructure coped pretty well. Heathrow actually has "not one but three power sources" – but switching all power to the two other substations required a huge, hours-long system "reset". Of course that's "disruptive". But within less than a day, a huge blaze fed by the transformer's 25,000 litres of cooling oil had been brought under control; thousands of homes had their power back; and hundreds of planes were aloft. How's that for resilience? If anything, it looks like officials may have been too cautious, said Andrew Gilligan in The i Paper. Heathrow's boss is facing questions about the decision to close the whole airport, when two of its terminals still had power. It's indicative of our "growing culture of managerial caution", where overregulation has programmed officials to shut things down at the first sight of disruption – even if it comes at "significant economic cost".

The Heathrow shutdown shows us just "how vulnerable the UK is", said James Ginns in the Financial Times. Too many parts of our critical infrastructure can be crippled by "a single point of failure". An alternative power source should have been "seamlessly" available to Heathrow; the fear is that there are similar vulnerabilities across our infrastructure, from undersea data cables to the electricity grid. It's particularly worrying in this time of "hybrid warfare", said Jack Dickens on Reaction, when our foes are looking to exploit gaps in our defences. The Kremlin doesn't appear to be behind the Heathrow chaos, but hostile states "will no doubt be taking note".

Arlene Foster's career has to be seen through the lens of her childhood, says Gordon Rayner in The Telegraph. In 1979, when the former DUP leader was eight, her father, an RUC policeman, was shot by IRA gunmen who had lain in wait for him at the family smallholding near the Irish border. The bullet struck his head, but only grazed his skin.

"He crawled into the house, bleeding," she recalls. "He brought us all upstairs to my parents' bedroom – myself, my two siblings, my mother and my grandmother – we were all lying on the floor. I'm sure my father was thinking… 'Will they come and finish it all off?'"

They moved, but she was always scared that the terrorists would come back; and her father had to live knowing that one of their neighbours had set him up. Then in her teens, she was on a school bus when an IRA bomb blew up under it. She was by the window, having asked a friend's sister to swap seats with her; as a result, that girl caught the full force of the blast as it came down the aisle. She survived, but the driver's son later killed himself, plagued by the thought that he should have checked under the bus.

"A lot of people who weren't directly killed by a bomb took their own life or suffered for the rest of their days," says Foster. "The huge toll of the Troubles will probably never be properly documented."