A new policy will be introduced next month forcing architects and developers to measure embodied carbon in their designs.
The requirements are part of the new Sustainable Buildings State Environment Planning Policy to be introduced in New South Wales in October, 2023.
It signifies a shift in how industry reduces CO2 emissions in the built environment with the focus moving away from energy efficiency to reducing embodied carbon.
University of NSW associate professor, Philip Oldfield, who is head of the School of Built Environment, said construction needs to have the smallest possible impact on the environment.
“Every square metre we build has a carbon footprint, and that can be quite high, because the materials we rely on to construct buildings are very carbon intensive. But we can’t simply stop building,” he said.
“We have a social obligation to provide healthy, comfortable, safe and sustainable places for people to live, to work and to play, around the world.”
Embodied carbon is the greenhouse gas emissions associated with creating a building, maintaining it over its life, and eventually demolishing the building.
The Australian construction industry is responsible for 18.1 per cent of the national carbon footprint or more than 90 million tonnes of greenhouse gas emissions every year.
“We have relatively mature building regulations focused on reducing operating emissions. But there are very few regulations concerning embodied emissions anywhere in the world,” Oldfield said.
“Any new building constructed in Australia today, we expect at least half of its total carbon footprint over its life will be embodied carbon, possibly even more.”
The World Green Buildings Council (WGBC) has set a target for all new buildings to be net zero operationally by 2030. What this means is the carbon footprint of buildings will effectively be all about embodied carbon.
Oldfield said this necessitates a big shift in thinking about how to create sustainable buildings.
He said this challenge is made more difficult in the context of a growing world population and increasing urbanisation.
The WGBC has set two targets around embodied carbon. The aim is for all new buildings, infrastructure and renovations to have at least 40 per cent less embodied carbon by 2030 and to reach ‘net zero embodied carbon’ by 2050.
There are four ways to reduce embodied carbon including adaptive reuse, which means maximising the use of existing assets.
Architecture needs to shift from automatically building new buildings to thinking more about reuse and redesign.
“Keeping the structure and becoming increasingly creative about building around it, is a design strategy with big CO2 savings,” Oldfield explained.
A good example is seen in preparations for Paris 2024 and Los Angeles 2028, with a shift from planning new buildings to host the Olympic Games to using existing venues, retrofitting and creating temporary buildings.
Brence Culp, LA2028’s chief impact officer, said the most sustainable venue is the one that doesn’t need building.
“To tear down a venue and build a new one, purely from an environmental standpoint, represents an enormous carbon footprint. For us, working with existing venues is the best way to go,” Culp said.
An example closer to home is the upcycling of the Quay Quarter Tower in Sydney.
Oldfield said the radical upcycling of a 1970s office block to almost double the floor area while saving around 7,500 tonnes of CO2 as well is impressive.
“The building retained more than two-thirds of its original structure, including beams and columns, as well as 95 per cent of the building’s original core,” he said.
Another two ways to reduce embodied carbon is to build smaller and to use the right materials.
“Medium density housing and apartments tend to be smaller, more compact and often share amenity and infrastructure, all of which reduces embodied carbon,” Oldfield said.
"Replacing carbon intensive materials such as steel and concrete with lower carbon equivalents is important for reducing embodied carbon."
Making use of biomaterials like timber, bamboo, straw, cork and even hemp (which can be used to make hempcrete) leads to lower overall embodied carbon, as they use less energy to create, and store carbon absorbed during their growth.
Timber is a great material to use to reduce embodied carbon, according to Oldfield.
“It’s like the anti-concrete. Cement is responsible for eight per cent of global CO2 emissions. To put that in perspective the aviation industry is around 2.5 per cent – and just think about how much bad press air travel gets,” he said.
“Our research has shown that if we can increase our use of timber up to 30 per cent of all new multi-storey buildings by 2050, this will play a key role in getting the built environment down to net zero emissions.”
Finally, the building and construction industry can dematerialise.
The structural steel used in 19th century buildings was delicate and thin in comparison to a lot of structures today. At that time, materials were expensive but labour was cheap so it made economic sense to design in this way.
“Innovations such as 3D concrete printing are already being used to minimise the amount of concrete in some buildings. A recent innovation has been the redesign of concrete beams,” Oldfield said.
“Think less is more in everything from the structure of a building to finishes and fixtures.
“For example, instead of suspended ceilings, no ceiling and exposed beams. Instead of carpets which need to be replaced every 10 years have polished floors. It’s about questioning whether you need every material in the first place.”
