In the race to reach net-zero emissions within 2050, architects and city planners are studying methods to reduce the impact of urban sprawl. An important aspect is finding innovative ways to construct our houses, offices, and infrastructure in a climate-smart way. A Swedish city has recently completed a revolutionary project, proving how sustainable buildings can play a huge role in reducing the impact of cities on the environment.
Among all types of ecosystems, urban areas produce by far the biggest amount of carbon emissions. Despite accounting for less than 2% of the Earth’s surface, data from UN Habitat shows that cities consume 78% of the world’s energy and produce more than 60% of greenhouse gas emissions. Air pollution is one of the biggest environmental issues related to urban areas and most of it is caused by heating systems, traffic, and construction sites, with building work alone responsible for more than one-third of global energy-related carbon emissions. Cement, one of the most common materials used in construction works, is the largest single industrial emitter of CO2 in the world.
Urban areas are studying ways to reduce their environmental footprint and slow down global warming, and finding innovative methods to build sustainable buildings has become a crucial part of the equation. Several cities have designed outstanding architectural masterpieces notorious for having a minimal environmental impact. Examples can be found all over the world, from Sydney to Shanghai, from Milan to Copenhagen, and from Toronto to Mexico City.
Among the many green constructions scattered around the world, one in particular stands out: the newly completed 75-metre-high Sara Cultural Centre in Skellefteå, a small urban centre located in the heart of the Bothnian Bay. The 20-storey building, named after a popular Swedish author, is home to six theatre stages, a library, two art galleries, a conference centre, and a hotel. What makes it unique is the fact that the centre was built entirely of wood – 12,000 cubic metres to be precise. It is among the tallest wooden towers in the world, second only to another Scandinavian masterpiece, the multi-purpose structure completed in 2019 in Brumunddal, Norway. However, the centre is not the only construction of its kind in the Swedish city, which for centuries has relied upon the abundance of timber in nearby forests to construct its buildings.
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While cement constructions have an enormous environmental footprint, wooden buildings do exactly the opposite: they sequester carbon dioxide from the atmosphere and store it forever. Architects behind the project claim the centre will capture nearly nine million kilograms of carbon dioxide throughout its lifetime. Timber has by far the lowest impact on the environment compared to all other commercial materials and it also has great thermal insulation properties, useful in preventing heat energy from escaping. To further reduce its environmental impact, the building has also been equipped with highly efficient solar panels that will power it and store excess energy in the basement.
While it was first ruled out for fears related to fire outbreaks, timber has been found to perform well in fire after extensive blast testing was conducted in the US. A study published in 2019 also confirmed its capacity to absorb carbon dioxide emissions, demonstrating that one cubic metre of CTL wood sequesters approximately one tonne of CO2. Lastly, constructing buildings with CTL is a much faster and less labour-intensive process that is also ultimately responsible for minimal waste generation. Given its remarkable characteristics, cross-laminated timber (CLT) has quickly spread across the world, with several European countries and most recently also many US-states using it in the construction of sustainable residential buildings. Of course, mass timber must be coupled with climate-smart forestry. And while experts believe that there is enough wood to use for the construction of buildings around the world, it is imperative that we take good care of our forests. Instead, we are still chopping down 10 million hectares of trees every year.
Featured Image: Courtesy of Ted Logart/imagebank.sweden.se