I travelled to Oslo in the early autumn. It felt like arriving into the future. Or, at least, a fragment of a possible future. I drove north in the quiet digital bubble of my electric rental car. In 2024, Norway became the first country in the world where electric cars outnumbered petrol cars.
A smooth, pristine motorway unfolded between farmlands and low hillsides of dense green forest. Long tunnels carried the route up above the banks of Lake Mjøsa, Norway’s largest lake. After a little more than an hour, the road curved downward to run parallel to the lakeshore.
Through gaps in a line of golden birch trees, a tall, slim structure broke the horizon. It rose from the water’s edge, topped by a triangular crown of bare, interlocking beams. Against the heavy grey sky and the enfolding mist, it radiated a gentle warmth from its pale burnt-orange exterior. The only building of any height anywhere in the surrounding landscape, it is known as Mjøstårnet, the “Tower of Mjøsa”: an 18-storey, 277ft (84m)-high wooden skyscraper. The tallest all-timber building in the world.
Mjøstårnet occupies a slice of shoreline next to the small town of Brumunddal. It incorporates offices, apartments, and a 72-two-room hotel. I was staying on the 11th floor, and I rode up in an elevator shaft fabricated entirely of wood (although the elevator cabin itself was made of steel and glass).
Two sides of my corner room had large picture windows, one looking west across the lake and the other north along the shore. There were wooden floors throughout, wooden tables and lamps, a wooden bed, and pair of low swivel chairs formed out of thin slats of bent pinewood.
Most striking of all was the huge wooden column that formed both the corner piece of the room and – extending in segments above and below me – one of the four edge-points of the whole tower. It looked reassuringly sturdy, as if it were the trunk of a massive tree that had been stripped of its bark and worked into a smoothed organic approximation of a geometric strut of steel or concrete. Which is almost exactly the case: except that it is not just one tree but many – a series of blocks of timber that are precision cut and then pressed and held together using extremely strong glue, creating what is known as mass timber, or glulam (short for “glued laminated timber”).
The piece in my room was the largest of its kind in the building, its cross-section measuring some 2ft wide by 5ft (0.6m by 1.5m) long. Although coated in a pale wax laminate, you could still see the unique knots and whorls running across its composite slices of wood.
Through the window, mist slipped in waves down the forested slopes of the far shore. Gusts of wind blew fine rain against the glass. Inside, there was no sound. The view shifted from white, to grey, to the encroaching blue of night. Eventually I settled down to sleep in what, I realised then, amounted to something of a childhood fantasy – a giant treehouse in the sky.
Mjøstårnet began its life as a sketch on a napkin. Two rectangular boxes marked out in blue ballpoint pen: one lying flat, the other standing on end, on top of the first. The actual finished structure is not far removed from this original draft – except that the second rectangle kept elongating farther and farther upward. “Height was very important here,” Arthur Buchardt, the developer who drew this sketch, told me. “It had to be a signal. To show what is possible. And I think now it has made a lot of people wake up.”
I met Buchardt the day after my arrival, on the 18th floor of the tower, where he keeps his own penthouse apartment. Now in his late 70s, he has the look of a Bond villain – tall, broad, vigorously healthy, perfectly bald – and the demeanour of a favoured great-uncle, quick to laugh and possessed of a twinkling, boyish enthusiasm. We sat at his living room table – wooden, of course – drinking black coffee and looking out through the floor-to-ceiling windows that form the entire western face of the penthouse.
All of the wood, Buchardt told me, gesturing around the apartment, and more generally at the whole building, came from the immediate landscape. In the centre of the room was an L-shaped pillar of grey marble containing a gas fire. That stone, he said, was taken from the surrounding hills. Even the art on the walls was local. “So this was a political statement,” he said. “To use all this local material.”
Buchardt moved to Brumunddal as a boy and spent most of his teenage years in the town. After graduating in business – studying at Oslo and Edinburgh universities – he returned to take over his father-in-law’s plumbing company. In a few years he sold it on, using the proceeds to move into property development, and then, when the 1994 Winter Olympics came to Lillehammer and the town needed brand-new accommodation for athletes and visitors, he built his first hotel. He has built 23 more since, all across Scandinavia. And, increasingly, he has built them out of wood.
“About 10 years ago I had to wake up a little bit myself. About the importance of the environment, about what we are doing to it,” he told me. It was the announcement of the Paris climate agreement in December 2015 – with its transnational pledge to reduce global emissions and shift toward net zero emissions – that prompted Buchardt into action. “Politicians talked about the need for a ‘great green change’. And I thought, how can I answer those political signals?” All he really knew how to do was make buildings. But what if he made them differently?
“It was right then, in 2015, that I put some drawings on this napkin. And I took it to an architect” – the Trondheim-based firm Voll Arkitekter – “and asked them, ‘How big is it possible to go with a high-rise wooden building?’ Because you can’t make large modern structures without steel or concrete entirely. But you can reduce how much you use. You can reduce that a lot.”
This is the thing about concrete. Not only is the world running short of the sand we need to make it – and having to consider extreme alternatives to meet demand, from removing and crushing entire mountaintops to dredging Greenland’s silt-plugged fjords – but its intensifying use also causes spiralling feedback loops. The built environment accounts for 37% of all global emissions, coming from the combination of the construction process itself and the energy required for heating, lighting and maintaining buildings over time. Between 7 and 8% of these total emissions are from concrete manufacturing alone. Since 1960, concrete use in construction has grown tenfold. Less than 1% of this concrete is produced from recycled materials. Instead, we just keep making more and more of it, requiring more and more sand – a projected 50% more by 2060 around the globe.
In effect, almost all of our modern towns and cities are formed out of materials that have been extracted, smelted, superheated or synthesised through the intensive use of fossil energy. Cities are, literally, monuments to extraction and emissions, the focused expressions of mining, burning, melting, sintering and moulding the mineral contents of the Earth. It would be hard to invent a more efficient machine for the concentrated emission of CO2 if you tried.
But what if you imagine replacing the superstructure of our homes and workplaces and offices – even our high-rises – with wood? Trees take carbon dioxide out of the atmosphere and store it inside their bodies. Cut them down, and they retain the CO2 rather than releasing it. Build with them, and they still keep holding that carbon. When you fabricate a typical mid-rise building out of steel and concrete, its construction alone generates around 1,500 to 2,000 metric tons of carbon dioxide emissions. That same building, when made out of wood, sequesters anything from 600 to 1,000 metric tons of CO2. And that is before you even factor in the additional absorption that comes with the planting and regrowth of the harvested trees.
For just one building, the difference is remarkable. What about an entire city? You turn dense population centres, some of the most concentrated emitters of greenhouse gases, into massive carbon sinks. You invert the equation, make buildings not part of the problem but part of the solution. You shift from a construction economy that is mineral based, requiring the ever more widespread depletion of finite resources, to one that is forest-based and endlessly renewable. Wood as an urban antidote to sand and steel and cement. From the concrete jungle to the timber city.
That, at least, is the vision. The reality, of course, is not quite so simple. Right now, for instance, construction with mass timber is expensive. The cost of Mjøstårnet came to around £100m. The same tower, built entirely of steel and concrete, would have been £10 to £15m cheaper.
Much of this, however, is a matter of perspective. Studies looking at the knock-on effects of global concrete production estimate that the associated damages it causes to health and the environment have a quantifiable financial value, a value that is almost equivalent to – or by some estimates may even exceed – the value of the entire concrete industry itself. A shifting, climate-focused economics can quickly change the parameters of cost efficiency. As can transparency over environmental impacts. “Ten years ago, I didn’t read what the CO2 footprint was of a car,” Buchardt said to me. “No one was that interested. Now the first thing you look at is the CO2. And I think that is how it will go with buildings.”
As he put it, “we will look at a certificate of each building, and you will see its CO2 emissions, its energy consumption, what it is made of. You will look at a particular hotel and say, you know, there’s steel, there’s glass, it’s using so much electricity, it’s like a beacon of emissions, and so you won’t stay there. While those who have low-carbon-emission buildings will go to the market, and they will tell you about it. Maybe it starts as a marketing tool, but then it becomes a standardisation.”
Brumunddal and its surrounding district of Ringsaker has always been logging country. Earlier on the morning I met Buchardt, I had visited the sawmill and factory of Moelven, a local company that has grown to become one of Scandinavia’s largest wood processors, and which supplied the materials for Mjøstårnet.
The head of its building systems division, Rune Abrahamsen, showed me the glulam production line. He led me from huge warehouses of newly sawn and delivered timber, stacked in neat piles like bundles of giant matchsticks, to a factory floor where computer systems cut, bent, pressed and glued the wood into any shape a client required. Everywhere was redolent with the smell of pine and spruce. Finally we came to a loading bay, about the size of an aircraft hangar, where finished glulam beams wrapped in blue tarp awaited transport all across the country.
Rune worked as the structural engineer on Mjøstårnet – tasked with turning Buchardt’s napkin drawing into a solid reality. “To be honest,” he said, “my first thought when Buchardt called me about this project was ‘Is he playing with me here, or is he for real?’”
Rune has always had a passion for timber construction. When he was a student in the 1990s, he said, everyone was focused on designing structures in concrete, steel and aluminum. “And there were very few people studying or searching for solutions in wood. And I thought, why do I need to be like all the other 250 students that I’m graduating with? Let’s try something else.”
He first began working with glulam about 30 years ago. The concept itself was actually more than a century old, but while the basic idea of cutting up logs and then gluing them together to increase stiffness and strength is the same, what has changed is the technology: the precision and speed with which you can now shape and manipulate the wood.
Building high, however – as high as Buchardt wanted Mjøstårnet to go – was something that no one had tried before. Timber buildings, Rune explained, are very light compared to concrete and steel structures. “And remember that buildings are vertical cantilevers. So when the wind blows at the top, it multiplies the forces, creating horizontal accelerations higher up.” It is, he said, like being in the crow’s nest at the top of a ship’s mast. Down on the deck, you may only feel the gentle rocking of the sea. Up on the mast, however, every pitch and roll becomes hugely amplified. Structurally, the wood can handle these forces easily – but those people actually staying on the higher floors might not.
To dampen the sway and remove the risk of “sea sickness” they had to weigh the building down – turning, in the end, to laying layers of concrete on the decks of the upper floors. This was a fraction of what most tall tower blocks would use, and the minimum they needed to meet “comfort” standards, but it was still there, nonetheless.
For the construction of the building itself, they used a novel and untested assembly technique. The hundreds of glulam beams, columns and trusses that formed the superstructure were processed and shaped to millimetre accuracy at the nearby factory, and then transported individually to the site without any trial fitting. In effect, Mjøstårnet was like a flat-pack skyscraper, its simple timber skeleton rapidly rising piece by piece and floor by floor – at the rate of almost one floor per week – all installed by a tower crane, with no need for any external scaffolding. Far faster than building with concrete.
With an all-timber structure, Rune said, there is one question that everyone asks: What if it catches on fire? From the spark that ignited and then consumed the “forest” of roof beams in Notre Dame Cathedral in 2019 to the great conflagrations in cities throughout history, wood’s capacity to burn is a major reason it has been largely phased out as a modern urban building material.
“Most people would think that this is a catastrophic thing to do,” Rune said, “to build such a tall timber building. But probably it is about the most fire-safe building in Norway.” The glulam had to undergo rigorous testing. “We made samples that we took to a fire laboratory in Trondheim. We burnt the glulam columns – and they do burn, but eventually they stop burning. It’s like if you go to the woods and you make a bonfire and you put a big log on late in the night. You go to sleep, and then the next morning, everything around the outside of the log is gone, the bark and such, and the log itself is deeply charred, but it’s still solid. So if a column in the building burns, it chars the surface but that charring protects the inside – and it is still strong enough to carry the load of the building.”
In this respect, Mjøstårnet has received a rather ringing endorsement. Norway’s largest insurance company insures the building – and also takes up two of its office floors. “You can prove as an
