They say you are what eat – your body is the sum of all the pies and chips (or blueberries and kale) you’ve consumed over decades. In the same way, our buildings are what they’re made of, and this can have huge repercussions for the health of our planet.
A new report from the World Green Building Council (WorldGBC), Bringing Embodied Carbon Upfront, has made a strong case for counting all the emissions involved in our buildings – not just the emissions produced by powering them.
Counting emissions from buildings is nothing new. In fact, in a time of climate crisis, it’s imperative that we do. We already know that buildings provide the cheapest and quickest way to address emissions. Buildings create 39 percent of all emissions worldwide – a huge percentage of global carbon emissions.
And we are only going to see more, with the floorspace of all buildings in the world set to double by 2050 as Earth’s population soars towards 10 billion. It’s the same story in Australia, where half of all buildings that will be standing by 2050 have yet to be built. We’re going to be building these buildings anyway, so we may as well choose for them to be as close to ‘zero net carbon’ as possible.
Australia is already heading down a one way road towards zero net carbon buildings. We have no choice if we are to meet our greenhouse gas emission obligations under the Paris Climate Agreement.
The Australia Sustainable Built Environment Council (ASBEC) has been a big part of this shift, with reports like Built to Perform pointing the way towards a future where our National Construction Code will require low energy buildings that are highly energy efficient and cheaper to run.
Australia’s governments are part of this change too. The Council of Australia Governments (COAG) Energy Council sees us as firmly on the path to more sustainable buildings, with their Trajectory for Low Energy Buildings. Numerous state government initiatives are also at play, like the Victorian Energy Upgrades program or the NSW Government Resource Efficiency Policy.
A key part of building low emission buildings is being able to assess how much carbon a building produces. And that’s where ‘embodied carbon’ – the focus of the new report – comes in. Until now, most of the focus has been on ‘operational carbon’ – the emissions from the energy required to run the building once it is built, powering functions like heating, air conditioning, and lighting. ‘Embodied carbon’ instead counts the emissions created by producing the materials, transporting them to the place where they will be used, assembling the building, and disposing of materials once the building has reached the end of its life.
Currently, embodied carbon represents about 11 percent of global emissions, but as operational carbon decreases, embodied carbon becomes a bigger proportion of all carbon emissions. Ignoring embodied carbon is a bit like hiding all the wrappers from unhealthy snacks in the back of a drawer. Just because the evidence isn’t right before our eyes doesn’t mean they don’t exist.
Compared to measuring the annual energy consumption required to power a building, calculating embodied carbon is a much more difficult task. In our globalised world, supply chains are so much more complicated, often crossing national and sectoral boundaries.
That concrete floor will be great as a thermal mass, using the sun’s energy to help keep indoor temperatures comfortable and reducing the need to produce emissions to do so – but do the emissions produced creating it outweigh this benefit? Is it better to demolish that 1950s house and build a super energy efficient home instead, or to retrofit what’s there with the latest energy efficient technology?
Standardised approaches for measuring embodied carbon will therefore be a vital factor, allowing those working on the ground to make informed decisions and prioritise materials and processes that create fewer emissions. The potential benefits can be enormous: The WorldGBC calculates that we could reduce global emissions from embodied carbon by 40 percent by 2030 and achieve genuine net zero carbon buildings by 2050.
ASBEC members are drawn from across the building sector, and as the report points out, we will need to work together, including with developers, designers, manufacturers and building material transporters, to truly account for embodied carbon. Many businesses across the world have already committed to the kind of change required to achieve major cuts in emissions.
Global construction group Skanska, for example, has implemented schemes to evaluate projects for full lifecycle impacts, and materials supplier Heidelberg Cement has committed to developing carbon neutral products by 2050. Australian company Lendlease is showcased in the report for their pioneering use of engineered timber in flagship developments like 25 King Street in Sydney, reducing embodied carbon by 75 percent while providing a quality product for clients.
Cities are also implementing the kind of regulation that can help move us in the right direction. Oslo, for example, is committed to fossil fuel free construction sites.
The City of Melbourne’s Climate Change Mitigation Strategy To 2050 addresses circular economy principles to reduce the environmental impact and embodied emissions from products, materials and buildings across the city through procurement, urban design and planning.
Climate change is the single biggest challenge we face globally. By acknowledging the truly global nature of our buildings, we can account for every bit of carbon involved in producing them. Instead of cheating on our carbon diet, we’ll be able to change our emission habits to deliver healthier and truly sustainable buildings.
Image: PBC Today