Here’s one of the bold ideas unveiled at COP26: what if buildings could act like trees, capturing carbon, purifying the air and regenerating the environment?

The well-known American agency Skidmore, Owings & Merrill (SOM, created in 1936) presented Urban Sequoia, an architectural concept that could be summed up in “forests of buildings”. These ‘forests’ isolate carbon and produce biomaterials that, in turn, fuel a new green and resilient urban environment. The project responds to the undeniable need to transform the building sector, which generates nearly 40% of all global carbon emissions.

Urban Sequoia favours materials that absorb more carbon: bio-brick, hemp concrete or wood. With a reduction of the carbon impact of around 50% compared to concrete and steel. 

A principle that can be applied all over the world

The SOM tower can capture up to 1,000 tonnes of CO₂ per year, or the equivalent of 48,500 trees. After 60 years, the prototype should also absorb up to 400% more carbon than it could have emitted during the construction phase. In addition, the biomass and algae integrated into the facades transform the building into a source of biofuel that powers heating systems… and even cars. 

But the idea goes beyond the simple building: by designing landscapes that absorb carbon and equipping the streets with technologies going in the same direction, old grey infrastructures (roads, sewers…) will be able to sequester up to 120 tons of carbon per km². 

The considerable impact of the project would have the potential to create a circular economy that absorbs carbon and de facto transforms the built environment from a problem into a solution to the climate crisis. 

Tags: carbon neutrality, circular economy, Cop26, Ownings & Merrill, Skidmore, SOM, sustainable construction, urban sequoia