Written By: Angela Hu
A few days ago, I competed in a debate tournament where we debated the harms and benefits of urbanization, or the movement of people from rural to urban areas. 56.2% of our world now lives in cities, with Africa and Asia having the greatest increase in urban citizens. However, an important thing I learned is that urbanization has resulted in more pollution. The increase in skyscrapers is one reason for this. Steel and concrete are the most commonly used materials to build skyscrapers. However, they release huge amounts of CO2, contributing to global warming.
Introducing Engineered Timber!
As a result, alternative materials such as wood are becoming increasingly popular. The Mjøstårnet, built in 2019, is made of wood and 85 m tall! Rather than common lumber, a type of wood known as engineered timber seems to be the most promising alternative. Engineered timber can be designed to provide high levels of strength, while also being up to 80% lighter than materials like steel. Cross-laminated timber is one example, created from thin layers of crisscrossed lumber.
Engineered timber replaces environmentally damaging materials like concrete and steel. Additionally, workers can assemble it into large sections while at the factory. This results in fewer delivery trips to construction sites, and thus fewer transportation emissions. A building in Cambridge saved more than 300 tonnes of CO2! This was a result of being a wood building, rather than steel. Additionally, trees take up and lock carbon in their wood. By using wood for buildings, this carbon isn’t released back into the atmosphere by insects such as beetles or fungi.
Since skyscrapers have concrete floors that take a long time to dry, builders need to wait weeks per floor. However, builders can simply cut in shape and assemble engineered wood. Wood is also a lot more flexible than other materials, which can be useful for those in areas with frequent earthquakes.
The thought of living in a building made of wood may raise some concerns. Despite my initial thoughts, timber is fire resistant, as a charring layer protects its inner core. If this isn’t enough, fireproofing layers can be added for more protection.
Next, wouldn’t wooden buildings result in deforestation? As it turns out, this isn’t a large obstacle. Scientists think that a decent sized apartment would only need the amount of timber that Europe’s sustainable forests grow every 7 seconds.
There is one real problem to think of. Recall that I mentioned wood is very light! The higher up a building goes, the stronger the winds are. Lighter wooden buildings are more likely to run into stability issues.
All in all, wooden skyscrapers can help balance urbanization and climate change. In the coming years, we’ll see if they become the new standard.