In northern Norway, trees are rapidly taking over the tundra and threatening an ancient way of life that depends on snow and ice.
Altafjord is a wide expanse of black water on the edge of the Barents Sea, ringed with mountains. Alta is a relatively large town in the Finnmark province, the crown of the horse's mane that forms Norway's jagged coastline and Europe's northern shore. Here at sea level the most northerly trees in Europe are moving upslope, gobbling up the tundra as they go. The people and animals that live here are trying to make sense of the rapid changes with a mixture of confusion, denial and panic.
Dawn at 70 degrees north during winter lasts nearly the whole day. The sun never rises, the day is permanently on the verge of breaking. It is disorienting. On the way to city hall from the guesthouse, I spied few pedestrians. Alta is a town built along American principles - that is to say a town built for a world in which petrol is cheap and cars are taken for granted. It is a landscape of shopping malls, gas stations and spaced-out residential suburbs. Normally at this time of year it isn't safe to be outside for long without wearing animal skins, but on the day of my visit it was only -1C.
All along the road to the city centre were rows of young Scots pines, their orangey bark contrasting with the fresh dusting of snow. Intermingled with the pines were shorter, ragged-looking trees with lumpy trunks, wizened branches and fine twigs like gnarled fingers: Betula pubescens, downy birch. It is these trees that had brought me here, to the office of Hallgeir Strifeldt, the director of planning for the municipality of Alta, at 9am on a Monday in the middle of winter.
As the planet warms, the Arctic treeline is accelerating towards the pole, turning the white landscape to green. The trees used to creep forward a few centimetres every year; now they are leaping north at a rate of 40 to 50 metres a year. In the European Arctic, the birch is the leader of the pack.
Downy birch is one of few broadleaved deciduous trees in the Arctic and it is hardier even than most conifers. Its "down" is a soft coating of hairs that acts like a fur coat in the punishing cold. Often found cooperating with pines and spruce at lower latitudes and altitudes, above a certain point the birch leaves the others behind and goes on alone for hundreds of miles.
It might be unprepossessing, even ugly, with its stumpy branches and pockmarked bark, but this tough little tree is a survivor and a pioneer, essential to nearly all life in the Arctic. Used by humans for tools, houses, fuel, food and medicine, it is home to microbes, fungi and insects central to the food chain, and it is critical for sheltering other plants needed to make a forest. The downy birch dictates the terms of what can grow, survive and move in the areas in which it takes hold. And, as the Arctic heats up, that range is expanding fast.
Alta's town hall is a modern timber-clad building radiating orange light. The entrance vestibule is a two-stage affair, like a submarine airlock, where you must pass through a bath of blasting hot air. When I arrived, the receptionist was in a good mood. She, like everyone in Alta, was relieved. Finally, there was some snow and finally the temperature was below freezing, even if only just.
"It gets very dark when we don't have any snow," said Strifeldt, ensconced in his modern office. Winters have been getting gradually warmer in recent years, but the warmth when I visited was, he said, "extreme". The whole community had been in a state of panic, reindeer herders posting photos of a snowless tundra on Facebook.
Strifeldt is a city dweller, a mild man with rimless glasses and a reserved air. He is also half-Sami, the indigenous people of Arctic Europe who share DNA and a common linguistic heritage with the peoples of the circumpolar region, from Finland to Russia across the Bering Strait to Alaska, Labrador and back to Greenland. The Sami used to migrate across the land without hindrance, but now the 80,000 who remain find themselves instead citizens of one of four different modern nations: Norway, Sweden, Finland or Russia. They are the only indigenous group in Europe recognised by the United Nations.
Reindeer are central to Strifeldt's identity, as they are for all Sami. His mother's family were reindeer herders, but when his grandmother died in childbirth on the plateau, his grandfather brought his infant mother to Alta, and left her with a Norwegian family to raise. The grandfather went back to his herds beneath the wide skies of the plateau, to his laavo - a traditional tent much like a tipi - and married again. Hallgeir has a foot in the city and the laavo. When I saw him later that week at a Sami cultural event, he was wearing the traditional Sami felt jacket embroidered with gold, a silk scarf, reindeer-skin trousers and boots and an elaborately worked silver belt.
Reindeer are endearing animals, with their wide brown eyes, furry antlers, soft fur and enormous snow-proof padded hooves. Sami herders recognise every member of their herd individually. Love is an insufficient word for the relationship: codependency comes closer. The people move because the reindeer move in search of grazing. Their culture has evolved around the migratory needs of the herds. But the breakdown in weather is upsetting this cycle. The Sami are among the first victims of climate breakdown, forced to contemplate a little earlier than the rest of us the collapse of a whole culture.
The reindeer are the only pillar left of what was once a more diversified civilisation. The forest Sami are long gone, forced by the Norwegian government over a century ago to choose between reindeer husbandry or assimilation. The integration of the fishing Sami has taken longer, but the collapse in cod stocks has helped accelerate the move to the towns, a process that it is Strifeldt's job to manage. Alta is a boom town of 20,000 inhabitants, growing as the countryside all around is drained of people.
Reindeer herding is valued by the rest of Norway and so it has persisted. The Norwegian state sees reindeer as a farmed resource, with quotas and subsidies and strict controls on culls. To the official mind they are a commodity, a useful export from the otherwise unproductive vast plateau of the north, but for the Sami the reindeer's significance is not only economic and cultural, it is also symbolic. "Reindeer are life. They are everything. Without reindeer, we die," Strifeldt told me.
And now reindeer herding, a way of life that has survived intact for 10,000 years, is under threat. This time it is not the Norwegian government that poses the greatest danger, but the climate. Warmer winters are deadly for the reindeer in two ways: one is short and sharp, leading to a quick death - ice; the other is slow but sure - too many trees.
Once upon a time, the first snows of winter would fall some time in October, initially on the tundra, the plateau above the treeline, and then on the pine and birch forests of the river valleys and the coasts. Shortly after, the mercury in the thermometer would descend below freezing and stay there until April or May, when the snow would begin to melt and the rivers would rush with the clear turquoise of superoxygenated ice. Until 2005, the average winter temperature in the region was -15C and it would reliably sink below -40C at least once during the winter, eliminating even the hardiest of all insect larvae, a process that kept the Arctic pest-free in the summer.
This world of winter was dark and cold and dry. At those temperatures there was no moisture at all. The snowpack was the consistency of sand, made up of several layers of large snow crystals. At -40C or-50C in the middle of winter, the quality and nature of snow crystals is critical to the survival of humans and animals alike.
When the temperature climbs back up towards zero or, even worse, above it, this delicate winter ecosystem collapses. Even a little warming of the snow can create havoc. Moisture starts to appear in the snowpack at -5C or -6C, at which point it loses its sand-like quality, and the snow starts to compact under the reindeer's hooves, ruining the grazing beneath. If the thermometer goes all the way into the positive, as it has done increasingly in recent years, it is a catastrophe. Melting snow or rain will freeze when the temperature goes negative again, forming a crust of ice over the ground, locking the vegetation away from the browsing reindeer. This happened in 2013 and again in 2017. Tens of thousands of reindeer died; some herders lost more than a third of their animals.
In the past 130 years, the temperature has crept above zero three times during winter - two of these times were in the past decade. From now on, the projections say every winter will experience days above zero. Reindeer herds can be up to 20,000 or 30,000 strong, and they are spread out across thousands of square miles of the Finnmark plateau. Artificial feeding is impractical, not to mention far too expensive. Something is going to have to give.
Warmer winters mean that the reindeer herds need more space in which to feed. Competition for the grassy tundra of the plateau is increasing from other reindeer, from windfarms, pylons, roads and mines. But the most formidable challenger is the humble downy birch.
The office next to Strifeldt's belongs to Tor Håvard Sund, manager of the Finnmark forest service. Sund is a large man in a checked shirt with an open face and a warm smile. As we were talking, we consulted the huge map that forms one wall of his office, but he quickly got frustrated.
"When was this map printed?" he asked. We located the date in small print at the edge: 1994. "This is totally useless," he said. "We need new maps. The treeline is out of control."
Several interlinked factors affect the habitable range of tree species: the availability of sunlight, water and nutrients are prerequisites, but these interact with other variables such as wind and temperature. Tiny gradations in altitude or latitude can mark large differences in vegetation. The downy birch detected the current warming trend much earlier than most scientists. This tree loves the warmer weather. It used to be confined to the dips and gullies on the plateau, away from the icy winds, but, unleashed by the warmth, it is storming over the top and out into the open, moving upslope at the rate of 40m a year. An enormous amount of territory is being transformed from tundra into woodland.
On the face of it, more trees might sound like a good thing. The problem is that the greening of the tundra further accelerates the warming process, as the birch improves the soil and warms it with microbial activity, melting the permafrost and releasing methane - a greenhouse gas 85 times more powerful than carbon dioxide in its warming effects over a shorter timeframe.
Birch is a pioneer tree. In spring it can sense when the nights are getting shorter and the temperature is warmer, and when the timing is right, it flowers with two sets of catkins. After pollination the downy buds covered in fine hair break open to release countless little winged seeds on to the wind. A good year for seed dispersal is called a mast year. Every year is a mast year these days. Before, the growing season was May to October; now it is April to November.
"Sooner or later, the whole of the plateau will be covered in trees," said Sund.
It takes 160 years for an old-growth pine and birch forest to form - one that is suitable for reindeer to graze in. In Norway, aggressive tree growth is now creating havoc. The birch is racing over the tundra faster than the pines can keep up.
This is bad news for the reindeer and the humans who rely on them. Upright birch forests don't develop a canopy; they are more like thickets. Without a canopy, they trap more snow, their mass forming a windbreak for drifts too deep for the reindeer to walk or dig through. Their roots warm the ground below, causing ice and melt around them. In time, a hectare of birch will deposit three to four tonnes of leaf litter on the ground, further improving the organic composition of the soil and encouraging other plants. Reindeer do nibble the twigs of young birch, "but even if you doubled the number of reindeer in Finnmark county you could not stop the birch", said Sund.
Every year more and more herders beg Sund to cut the birch to protect the precious tundra habitat needed for reindeer. And so the herders who traditionally considered themselves a part of the natural world, not distinct from it, are fighting a losing battle against nature.
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