'So what does a building that has burped 70% less carbon in its creation look like?'

This is the year when architects have to get to grips with embodied carbon, says Maria Smith.

This year, architecture is going to get to grips with embodied carbon. It’s a collective New Year’s resolution we’ve – perhaps unwittingly – made via Architects Declare, the RIBA 2030 Challenge, the new London Plan and other shifts within our industry. 2019 was the year we declared an emergency. 2020 will be the year we measure and declare our figures!

Architects Declare (now signed by over 800 practices) includes pledges to incorporate whole life carbon modelling in our basic scope of work and accelerate the shift to low embodied carbon materials. The RIBA 2030 Challenge sets numerical targets for carbon emissions per square metre built and is phasing these in as criteria in their awards. The new London Plan, due to be adopted in the spring, requires all referable and called-in schemes to include embodied emissions assessments as part of a circular economy statement. BREEAM 2018 will even give you a few points for showing you’ve tried to reduce your embodied carbon.

Soon we might see Local Authorities, especially those that have declared a climate emergency, adopt the London Plan requirements through their own local plans. Twenty four “real estate giants” have committed to publishing their portfolio’s embodied and operational carbon starting at the end of this year, so we can expect clients to be demanding this information of us too.

What does this really mean for the type of architecture we build, the type of architecture we lust over, and the design ethics and design processes we hold dear? The RIBA estimates that we’re currently emitting around 1 tonne (1000 kg) of carbon dioxide (equivalent) for every square metre we build (equivalent because methane has 25 times the global warming potential of carbon dioxide, and nitrous oxide almost 300 times). These emissions come about during the extraction of raw materials, manufacture, transport, and installation of the materials that make up our buildings. These emissions all occur before the building is even open and using energy to heat and cool and power. This sets the starting point, upon which year on year your building adds to its initial “carbon burp.” RIBA says we need to get from 1000 kg to 300-500 kg CO2e/m2 by 2030. Of course this is a rate per square metre so it also depends how much we build and further interrogation of these figures with reference to the Committee for Climate Change’s carbon budgets suggests we need to cut deeper and faster. 

So what does a building that has burped 70% less carbon in its creation look like? And how should we go about designing it? To begin with we need to start every project not with a Rotring scribble of the site and a gleam in our eye but a beautifully formatted spreadsheet containing an audit of any existing building fabric we can get our hands on. We should be using everything that’s already burped to its full potential – so a perfectly good steel UB should be used structurally not as a jaunty feature. 

Then when we do put mouse to model space, we need to be drawing lovely fat walls. The temporary, anomalous availability of high performance, high carbon materials like concrete and steel have given us a taste for Farnsworth House-esque slender elegance and Sydney Opera House anything’s possible-ism. But in a climate where go to materials ought to be the likes of cob earth, unfired blocks, hempcrete, and straw bales, it’s the deep reveals we need to delight and revel in. These low carbon materials might be weaker and therefore fatter but many can provide that precious thermal mass for a fraction of the carbon cost.

Arguably most critically, we need to collaborate with plants. Their bit is to capture the carbon, our bit is to store it, and where better to store piles of timber, straw and hemp than in buildings? Yes this challenges our conviction that buildings ought to be so durable they never need even a going over with a feather duster, but again this was a temporary, anomalous period and an ongoing custodial relationship with our built environment is much more sustainable.

This year, architecture is going to get to grips with embodied carbon. And excitingly this isn’t just going to mean relatively invisible material substitutions. No, this is challenge-of-a-generation stuff and we’re going to see a radical shift in what innovative design looks and feels like.

Maria Smith is a Director at Webb Yates Engineers where she leads a transdisciplinary team specialising in reducing the carbon emissions associated with the built environment.