The lowdown on embodied carbon

30 Aug 2021

Imagine removing 13.8 million cars from Australia’s roads for an entire year. Cutting embodied carbon in buildings by just 10% between now and 2050 would have that level of impact, eliminating 63.5 megatonnes of emissions.

This statistic points to the possibilities – but also tells us that we have a huge problem to tackle. The Green Building Council of Australia’s Head of Market Transformation, Jorge Chapa, doesn’t sugarcoat the challenge ahead. “The size and scale of our embodied carbon problem is enormous. There is no question about it,” he says.

In 2019, embodied carbon accounted for 16% of built environment emissions. Without action, this share will balloon to 85%. This is the headline figure from the GBCA’s new report, Embodied Carbon & Embodied Energy in Australia’s Buildings, developed in partnership with thinkstep-anz and the support of the Australian Government.

The work comes as the IPCC sounds the global alarm that temperatures are likely to rise by more than 1.5°C above pre-industrial levels within just two decades.

“We’ve been really focused on operational emissions but until now we haven’t quantified the built environment’s embodied emissions. These have been hidden emissions but will become a huge problem because they are locked in as soon as the building comes out of the ground.”

Embodied carbon accounts for around 20-25% of a typical building’s total carbon footprint over its lifetime. But embodied emissions are hard to eliminate because some of our most common building materials – notably concrete and steel – require process heat and chemical reactions that can’t be easily decarbonised.

“I think in a lot of people’s minds, decarbonising the grid goes a long way to solving the problem of climate change. But it’s not the case for product manufacturing which has many other requirements, such as the need for high heat sources,” Jorge explains.

Materials makeover

There is a reason why concrete and steel are our go-to building materials: they are robust, fire resistant and reliable. But both also carry large carbon footprints, contributing around 8% of global greenhouse gas emissions.

There are few alternatives to concrete and steel. Both sectors have been busy innovating with low-carbon products, transparent reporting and environmental product declarations. While some hail hydrogen as the solution, Jorge notes we need significant investments to create true green hydrogen.

Materials supply chains may be moving towards sustainability, but they move slowly. “If you are investing in a steel mill or a quarry, you take a 30-year horizon. Asking for a quick pivot is a big ask – and it is to the credit of sector leaders that they are absolutely committed to this,” Jorge says.

“These industries really do understand their impact and are working hard to find solutions. It’s important we all work together, rather than pointing the finger, because we will continue to use concrete and steel for the foreseeable future. We just need to be smarter about how and when to use it, and to continue encouraging industry to decarbonise” Jorge says.

Property picks up the pace

Embodied emissions, once in the “too hard basket”, is now on the board agenda of the industry’s leading property companies as race to net zero shifts gears.

Lendlease’s Head of Sustainability, Ann Austin, recently noted that around 80% of Lendlease's emissions come from embodied carbon. “You can offset your flights, but no one offers you the chance to offset the concrete slabs and columns, or the steel framing of your commercial high-rise,” she told Green Building Voice last month.

The development industry is turning to alternative materials – notably mass timber – to reduce the amount of concrete and steel in buildings. Jorge points to Atlassian’s 40-storey office at Sydney Central, which will be among the world’s tallest hybrid timber towers. “A concrete superstructure every few floors will be interspersed with cross-laminated timber. It’s a really exciting project that will encourage innovation.”

Other project teams are looking to hold onto the embodied carbon in existing structures. By retaining around two-thirds of the original core of Quay Quarter, AMP Capital saved 6.1 million kilograms of carbon – equivalent to around 35,000 flights between Sydney to Melbourne.

“These are both great examples, but we need a lot more of them,” Jorge says.

Carbon certainty

“The challenges facing materials manufacturers – from concrete to carpet – is that they need policy structure. Everyone wants to understand the policy environment they’ll be operating within for the next three decades.”

Some policy signals are starting to emerge from beyond our shores. From 2026, the European Union will hit all export goods with a tax that is equivalent to around $90 per tonne of emissions created during production.

“Most Australian manufacturers don’t export to the EU, so they think it does not apply to them. But everything that the EU won’t accept will be directed our way – so we may find ourselves the dumping ground for higher-emissions, low quality products with even lower prices,” Jorge warns.

“This report is a call to action. Tackling embodied carbon will help us drive down emissions in our building stock, future-proof Australia’s energy-intensive industries and ensure we can compete in a low-carbon marketplace.”

Download Embodied Carbon & Embodied Energy in Australia’s Buildings