The Mjøstårnet in Brumunddal, Norway, was once the world’s tallest wooden skyscraper. Credit: Erik Johansen/NTB scanpix/Alamy
When the first skyscraper was built in Chicago in 1885 — a modest ten storeys — people were afraid to walk under the steel-framed building, fearing it would collapse. Today, as towers made of wood go up in cities around the world, the response is a similar mixture of wonder and fear.
People are concerned about the fire risk and the structural stability, but the truth is that wooden construction is healthier, both for people and for the planet. Buildings and construction are the largest source of anthropogenic greenhouse gases, responsible for nearly 40% of global emissions.
Nature Outlook: Cities
A building’s structural elements, typically steel and concrete, are “a huge component of that carbon footprint”, says Michael Green, architect and author of the 2017 book The Case for Tall Wood Buildings. “That means the most important thing we can do is change the materials we build with.”
Green’s firm, MGA, based in Vancouver, Canada, is designing what will be the world’s tallest wooden skyscraper: a 55-storey tower, the Marcus Center in Milwaukee, Wisconsin. It will take the title from Milwaukee’s 25-storey Ascent tower, which in turn outstripped the 18-storey Mjøstårnet in Brumunddal, Norway. Other wooden towers are springing up in Perth and Melbourne, Australia, as wooden skyscrapers around the world reach ever greater heights.
Spectacular though they might be, timber skyscrapers are not where a shift to wooden construction will have the greatest impact. The main gains will be found in the more numerous mid-rise buildings that make up a sizeable proportion of the world’s cities. But towers and other prestige projects offer an excellent opportunity to push the technology forward and demonstrate that wood can be just as safe as concrete and steel.
“To be honest, I’m not a fan of tall buildings,” Green says. “But I am a fan of reshaping the public’s perception of possibility.”
Urban carbon capture
People have been building with wood for millennia, and many low-rise residential buildings in North America and parts of northern Europe are made from it. But its use in mid-rise buildings, towers and other large structures was limited until the advent of engineered wood technologies, such as cross-laminated timber, in which several layers of wood are bonded at alternating right angles to improve the strength.
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