There is no silver bullet to tackle the challenges of decarbonising the built environment, but an industry event held across Zoom on Monday heard we may be getting close to an answer.


This year, against the backdrop of the climate crisis and a global pandemic, Monica Richter from WWF and Hudson Worsley and Ben Waters from Presync embarked on a journey to find out how best to deal with the issues of embodied carbon in the construction industry.

They spoke to more than 30 organisations, from building and construction contractors, material suppliers, policy makers, university researchers, and rating scheme bodies, to determine the biggest issues and how to face them.

Presenting their findings on Monday in collaboration with Lendlease, before an audience of more than 300, it was clear from the onset the building industry – responsible for about 38 per cent of the greenhouse gas emissions globally – requires urgent action.

As the event’s MC leading sustainability architect Caroline Pidcock noted, “the solutions are available, the challenges can be tackled and our planet cannot wait any longer. The time is now.”

A system-wide approach is needed, but it starts with government

Funded by the New South Wales Government, the Time is Now: Tackling Embodied Carbon in the Building and Construction Sector report by WWF Australia formed the basis for shaping Monday’s event.

The researchers had already spoken to dozens of industry stakeholders and assembled their key findings.

Driven by the NSW government’s ambitious stage one strategy to deliver a 35 per cent cut in emissions by 2030 – having already aligned itself to the Paris Agreement’s net zero carbon society by 2050 –  the researchers found momentum for change was building.

Hudson Worsley, co-founder of Presync, a business focused on technology, innovation and sustainability, stamped investors as the number one driver for action, but government procurement as the “single biggest lever”.

“The challenge of decarbonisation is compounded by the complexity of this ecosystem, the sheer number of moving parts, the number of decision points, and the culture of the construction sector,” he said.

“Collaboration… is a key word that underpins everything that we’ve been doing this year.”

Mr Worsley outlined the critical role governments play in regulation and policy, and as strong influencers. In sending the right messages to the wider sector, “enablers are key,” he said.

Mick O’Flynn, acting executive director of sustainability at NSW Department of Planning Industry and Environment, said the net zero plan is intended to facilitate a whole economy transition, with a clear focus on the economic opportunity decarbonising presents rather than the costs of reducing emissions.

“In the NSW Government we totally recognise that we have a really significant part to play in procurement and in other roles,” he said.

“One of the very many funded initiatives in the plan is a program to accelerate the transition to low emissions building materials.”

The NSW government is the biggest construction customer in the state, wielding enough influence to lead the necessary transition.

As it stands, there is little attention given to embodied carbon, researcher and co-founder of Presync Ben Waters said, and there is limited pressure to innovate, but the government can change that.

“The strongest theme in our research was that government procurement is the key lever for change, particularly in infrastructure projects, but it takes targets embedded into tenders, embedded into contracts to walk the talk,” he said.

“We don’t have a price on carbon… but one of our interviewees commented that there’s enough information, there’s enough local materials available already, the main barrier that we have is resistance to change.”

More innovative materials needed in Australia.

Decarbonising the building industry is complex. Construction represents between 10 and 15 per cent of Australian GDP, but also is also a significant contributor to greenhouse gas emissions.

Globally, production of concrete and cement make up eight per cent of total global emissions, equating to roughly the same amount of emissions produced from all the cars in the world.

While the single biggest driver of change to low-carbon materials would be a national carbon price, the report states, “in the absence of such a price, purchasers and industry need to factor in carbon content on all project decisions.”

We need competition and alternatives with materials

Concrete, steel, aluminium and timber were high on the agenda at the event, with the speakers noting that competition between materials should be encouraged and alternatives sought.

Within the concrete industry – dominated by global players and a significant carbon emitter – Australia is “not steering the ship to decarbonisation,” Mr Waters said.

“The steering comes from Europe, there are lower carbon options there, but here (in Australia) we ned to ask for them.”

He said finding a replacement for Portland cement, which is the most common cement around the world, is fundamental to reducing embodied carbon in buildings.

He pointed to geopolymer binders as an alternative material with around one-third the embodied carbon of conventional concrete and one fifth of the weight, leading to flow-on emissions reduction in transport.

Steel needs local alternatives

Steel, Mr Waters said, is another carbon intensive material “although we do have substantial local capability and some control over technology pathways.

“We can get today lower carbon steel from Europe, but it appears in this case that it might be preferable instead to work with local industry on a low carbon pathway to build local capability instead of importing greener stuff,” he said.

He pointed to a recent Grattan Industry Report, which underpinned the potential green steel had to make Australia a “renewable energy superpower”.

Ben Waters (left) with Hudson Worsley, Presync. Photo: Cassandra Hannagan

Smart design is a smart place to start

“For now, smarter design is a way forward,” Mr Waters said, “along with increased gathering of the recycled steel already in the economy.”

Aluminium can be part of the solution

Despite the large carbon footprint associated with aluminium production, it is one of the few materials with the potential to be part of the solution to the broader national decarbonisation issue.

“It’s a lightweight material with good long-term prospects in the low carbon economy, particularly in transport,” he said.

Unlike other materials, the embodied carbon of aluminium can be reduced with no fundamental process change – the carbon intensity is instead dependent on the source of electricity for the smelting.

“So unlike the other two (materials) where process emissions which are hard to avoid produce most of the carbon, it is really about the electricity,” Mr Waters said.

He added the decarbonisation of Australia’s electricity supply will make a big difference to aluminium’s carbon footprint.

Timber: an excellent replacement

Last year, Lendlease built its second timber building at Barangaroo in central Sydney, constructed with around 1,750 pieces of timber.

Wood structures can be built tighter, with better acoustics and thermal performance, and depending on the supply chain, timber can be carbon negative.

During the research phase of the report, timber was touted as an “excellent” replacement material, but lacked a driver for broad uptake.

Lendlease finds gloomy views

An emerging leader in innovative green builds, Lendlease has delved into eradicating embodied carbon, researching the views of their supply chain to find out why the uptake for low carbon materials has lagged.

“Much of the research is quite gloomy,” Lendlease’s national sustainability manager Ann Austin said, “there are quite a number of barriers.”

Risk, position in the supply chain, a lack of alternative options and putting cost above the perception of embodied carbon were recurring themes.

“The market is really not talking about embodied carbon at all,” she said.

“People aren’t asking for low embodied carbon… and this presents a big barrier because suppliers need to know there is a point to making an investment in innovation.”

Circling back to the notion that there is no silver bullet, Ms Austin said decarbonisation is bolstered by demand.

“And so if you remember one thing from today, perhaps it should be to remember to request low embodied outcomes, all the time,”  she said, “regardless of whether you’re an investor, a client, a designer, a structural designer, an engineer or somebody who’s working on the site.”

Establishing a Buyers Alliance

Overwhelming support for an impartial body that can support, advise and connect industry people on the path to decarbonisation has paved the way for the establishment of a Buyers Alliance.

“From the feedback we received at the event on Monday, there was a lot of support for knowledge sharing and establishing common targets for procurement and collaboration,” Monica Richter said.

Taking notes from the Business Renewables Centre Australia, which played a “catalytic” role in the take-up of corporate renewable power purchasing agreements, the report states, “an equivalent body could bring together suppliers, builders, developers, contractors, procurement professionals, engineers and architects, researchers and policy makers to accelerate the adoption of low- and zero-carbon construction materials.”

Ms Richter said a Buyers Alliance could be launched as soon as September, in time for World Green Building Week.

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  1. There are no silver bullets in this debate. Being a rock thrower from a single lens couch is not a solution either. There are many debates to be had, as long as these are conducted respectfully, with fact not opinion then a consensus will build.It will not build from unrealistic proposals such as whole new taxes or burdens on an industry now in deep structural stress. Any solution has to reflect the art of the possible – not some hypothetical single view. This has been my experience as NSW Building Commissioner over the last year. The reforming the construction industry conversation had many single bullet offerings at the end of 2019. Now we have a strategy we have consensus building, more considered inputs and constructive collaboration.
    For my part a systemic starting point is to get the entire construction value chain to focus on how to reduce on-site generated construction waste by 80% by 2025. A measurable impactive target. Immediately the debate about the best materials becomes secondary. Again my view – I think concrete and steel have a big future as those materials lower their carbon impact. They are, but it would be useful for all materials to bring their collective carbon certificate as they join up in a building – real carbon measures not theoretical. And it is worthwhile to ensure that the source and impact of mass timber is understood. Almost all is grown and sourced from the northern hemisphere. Australia has a trade imbalance of over $4bn through northern hemisphere timber imports. Australia has no forest strategy. It has approximately 17% of forest footprint now compared to when white settlers arrives. Land clearing continues apace. Trees take 20-years to grow.

  2. Embodied carbon is an almost complete red-herring. A low embodied carbon building has no insulation, single glazed windows. The carbon (dioxide equivalent pollution) from operating the building dwarfs the embodied (5-20% of the lifetime emissions) and context is everything – location, climate, building/infrastructure uses, design, services, controls.
    Aluminium is not a good substitute for steel because it’s not the weight that matters but the strength to weight ratio – you can use less weight of steel to do the same structural job as the aluminium and its carbon footprint is less than half that of aluminium. Stainless steel that’s infinitely recyclable is a better idea. Also “Green” steel is just as viable as “Green” aluminium and Gupta is developing it for Australia.
    Lastly until our grid is 100% supplied with renewable energy, every kWh of electricity diverted from grid supply keeps coal and gas fired generators running for longer, so even so-called green steel and Aluminium are really, from a marginal perspective, still fossil fuel powered.
    So, enough of the simplistic BS, we are running out of time for spruiking simplistic fixes and making the wrong-headed decisions and failing at every turn. Only full life cycle informed design can ensure the right decisions, but LCA itself has lost its way scientifically, with all of the recognised databases irretrievably compromised with flawed data. The ENVEST prototype LCA based design tool that I have been developing for nearly 30years has never gained traction – it has always been “too far ahead of its time” for designers and investors.

    1. thanks Nigel.., since this topic is now “trending” can you give us a quick bird’s eye view of your program? (Again, I know…) but for the uninitiated… this is a debate we need to have.

  3. Don’t demolish old buildings, urge architects
    https://www.bbc.com/news/business-53642581 Knocking down defunct structures sends a wrecking ball through carbon targets, architects say ….This staggering fact has only been properly grasped in the construction industry relatively recently. We’ve got to stop mindlessly pulling buildings down.”

    Don’t demolish old buildings, urge architects
    Knocking down defunct structures sends a wrecking ball through carbon targets, architects say
    Footage of buildings being flattened in a noisy demolition may be a popular feature of local TV news reports, but architects say such structures should be protected – to fight climate change.
    They say property owners should be incentivised to upgrade draughty buildings, not just knock them down.
    That is because so much carbon is emitted by creating the steel, cement and bricks for new buildings.
    The campaign by the Architects’ Journal is backed by 14 Stirling Prize winners
    In the past there was debate about whether it was better for the climate to demolish an old energy-hungry building and build a well-insulated replacement.
    But this is now widely considered a serious mistake because of the amount of carbon emitted during the construction of the new building.
    The massive CO2 emitter you may not know about
    The Royal Institute of Chartered Surveyors (RICS) estimates that 35% of the lifecycle carbon from a typical office development is emitted before the building is even opened. It says the figure for residential premises is 51%.
    These calculations suggest it will be decades before some new buildings pay back their carbon debt by saving more emissions than they created – and these are decades when carbon must be sharply reduced.
    The Architects’ Journal has now given evidence to the Commons Environmental Audit Committee (EAC) on the difference between operational emissions from heating and cooling a building and embodied emissions from creating construction materials.
    It wants the government to change the VAT rules which can make it cheaper to rebuild than to refurbish a standing building.
    Architects’ Journal managing editor Will Hurst said: “This staggering fact has only been properly grasped in the construction industry relatively recently. We’ve got to stop mindlessly pulling buildings down.”
    He said VAT on refurbishment, repair and maintenance should be cut from 20% to zero to match the typical rate for new-build.
    He continued: “It’s crazy that the government actually incentivises practices that create more carbon emissions. Also, if you avoid demolition you make carbon savings right now, which we really need.
    “In the past the government argued that the EU would forbid zero VAT on renovation – but they can’t use that excuse now.”
    And Alex Green, from the British Property Federation, said that sometimes the different VAT level is the key factor in determining whether a building is felled or saved for a new purpose.HousiTreasury Minister Jesse Norman previously told MPs that property owners already benefit from a reduced VAT rate on residential construction under certain conditions.
    He said: “Going further would be very expensive: reducing VAT on all property renovation, repairs and improvements would cost the Exchequer approximately £6bn per year.
    “The government has no plans to review the VAT treatment of construction.”
    What’s more, ministers recently said they would ease planning rules for owners wanting to demolish offices and replace them with new-build homes. …. Hurst has urged them to rethink that plan. He suggested the Treasury could raise the tax on new-build projects to compensate for tax reductions from refurbished buildings.
    He also suggested planning guidance should create a bias toward refurbishment.
    The Architects’ Journal evidence has been reviewed by the EAC. Its chair, Philip Dunne MP, told BBC News: “Prioritising retrofitting can offer huge benefits. “It enhances energy efficiency and boosts skills and green jobs quickly in the UK. It will be a crucial component for us to move to a low carbon economy.”
    The EAC will report its findings on the issue in the coming months.
    +++++++++++++++++++++++++++++++++++++++++++?