A year after Skidmore, Owings & Merrill (SOM) first debuted Urban Sequoia, a prototypical high-rise capable of sequestering up to 1,000 tons of carbon each year with purifying the air around it, the firm has returned to the 2022 United Nations Climate Change Conference (COP27) in Sharm El Sheikh, Egypt, with the same design proposal but in a “readily constructable” form resulting from months of additional research.
The beyond-net-zero approach embraced by SOM’s team considers buildings as self-sufficient living organisms (trees are the obvious comparison) capable of both reducing embodied carbon and absorbing carbon from the atmosphere all the while providing much needed new housing stock in urban areas. Per the firm, roughly 2.5 billion square feet of new construction will need to be built in cities by 2060 to meet skyrocketing population growth. Cities, despite claiming a scant amount of Earth’s surface area, are responsible for an estimated 75 percent of global carbon emissions. Urban Sequoia addresses both quandaries in a single, carbon-negating package built from timber and/or biomaterials and boasting a century-plus-long lifespan.
“Urban Sequoia is a systems approach, a philosophy,” explained SOM Sustainability Director Mina Hasman in a press statement. ““It is a way of thinking about cities as ecologies, as living and breathing systems that can be reconfigured to achieve dramatic reductions in whole life carbon, reframing the built environment as a solution for the climate crisis.”
Dubbed Urban Sequoia NOW, the ready-to-build evolution of the original prototype design was presented yesterday, November 8, by SOM Partner Chris Cooper at the conference’s Buildings Pavilion Auditorium. “We need to take carbon out of the atmosphere through the built environment, and we have developed a design to do just that,” Cooper said in a statement.
“We asked ourselves how low we can go in emitting carbon in construction, how high we can go in carbon sequestration, and how long we can go in extending the typical building’s lifespan,” added SOM Partner Kent Jackson. “Our latest concept for Urban Sequoia answers these questions.”
As detailed by SOM, Urban Sequoia, now a “buildable reality,” would reduce upfront embodied carbon by 70 percent from construction in comparison to standard high-rise construction. Over the first five years of the building’s life, a 100 percent reduction in whole life carbon would be achieved, enabling it to reach net-zero. Over the next 100 years, a building design and built using the Urban Sequoia framework would absorb more than 300 percent of the amount of carbon emitted in its construction and operations, the firm detailed.
As further elaborated by the firm, an Urban Sequoia would rise via a “reductive,” all-in-one construction approach that differs from the typical additive method in which carbon is added to the atmosphere through each individual step—i.e. facade work and interior fit-outs—in the building process. SOM describes the design of Urban Sequoia as an “inversion” in which all of the building systems normally tucked away out of sight in ceilings like air ducts and mechanical equipment, would “be consolidated or even eliminated” and replaced with a new approach that “optimizes the floor slabs to include those systems within the floors, and raises the ceiling heights simply by removing the ceilings altogether, significantly decreasing material use.”
The firm further details:
“Air would flow into underfloor ventilation openings, situated between the slab and a timber floor finish, as well as sky gardens doubling as amenities and large air capture zones. Cool air would move into these gardens and enter open cavities in the building’s core, where the stack effect would bring air up through direct air capture technology embedded within the building’s core and roof. The captured carbon would then be stored and available for use in various industrial applications, completing the carbon cycle and forming the basis of a new carbon-removal economy.”
The Urban Sequoia design, perhaps most crucially, is a highly adaptable on that can be applied to different typologies (not just housing) and be realized at “any scale, in any location” although dense cities with high levels of pollution are the target settings for a potential forest, if you will, of air-scrubbing towers. “Bringing this idea from concept to reality will create a network of Urban Sequoia buildings across the world that absorb carbon, every year, for the next 100 years or more,” said the firm.
More on Urban Sequoia NOW can be found here.