If we return to an age of wooden buildings, researchers have said, urban areas could turn into a major carbon sink.
A drastic material revolution in construction could be one answer to limiting the worst effects of the climate crisis. According to research from the Potsdam Institute for Climate Impact Research, if we were to turn back the clocks and construct buildings from wood instead of concrete and steel, urban areas could be transformed.
Firstly, the study found it would significantly reduce greenhouse gas emissions from the production of concrete and steel. Secondly, large, wooden buildings could become carbon sinks, storing atmospheric CO2 taken up from the air by trees that are harvested and used as engineered timber.
However, the researchers warned that while the amount of timber needed is available for such a transformation, there would be a clear need for sustainable forest management and governance.
Four scenarios of timber use to help climate stabilisation were simulated, spanning the next 30 years. Currently, just 0.5pc of new buildings are constructed with timber.
This could be driven up to 10pc or 50pc if mass timber manufacturing increases accordingly. If countries with current low industrialisation levels also make the transition, even 90pc timber is conceivable, the researchers said.
‘There’s no safer way of storing CO2 I can think of’
This could result in between 10m tons of CO2 stored each year in the lowest scenario, and almost 700m tonnes in the highest scenario. The harvesting of timber instead of producing concrete and steel would reduce greenhouse gases in half, researchers added.
It’s estimated that a five-storey residential building made from laminated timer could store up to 180kg of CO2 per square metre – three times more than in the above-ground biomass of high carbon density. Despite this, even if 90pc of buildings were constructed this way, it would sum up less than one-tenth of the overall amount of carbon stored above ground in forests worldwide.
Addressing the issue of fire safety, the researchers said that large structural timbers are comparatively fire resistant as their inner core gets protected by a charring layer if burnt.
Hans Joachim Schellnhuber, co-author of the study, said: “[Trees] take CO2 out of our atmosphere and smoothly transform it into oxygen for us to breathe and CO2 in their trunks for us to use.
“There’s no safer way of storing CO2 I can think of. Societies have made good use of wood for buildings for many centuries, yet now the challenge of climate stabilisation calls for a very serious upscaling. If we engineer the wood into modern building materials and smartly manage harvest and construction, we humans can build ourselves a safe home on Earth.”