The Past, Present and Future of Embodied Carbon, a Conversation with the Carbon Leadership Forum

The Carbon Leadership Forum (CLF) pursues a zero-embodied-carbon built environment through research, education and advocacy and by fostering collaboration.

To celebrate Thornton Tomasetti’s 10th year as a CLF sponsor, we convened a group of the organization’s leaders and members to discuss the past, present and future of understanding, measuring and reducing embodied carbon in buildings and infrastructure.

Chris Erickson: CEO and Co-founder Climate Earth (a company that produces EPDs for the concrete industry), founding CLF member.

Amy Hattan: Thornton Tomasetti corporate responsibility officer and Embodied Carbon Community of Practice co-leader, former CLF board member

Amanda Kaminsky: Director of Sustainable Construction for Lendlease's Americas portfolio, CLF advisory board member

Kate Simonen: University of Washington Professor of Architecture, CLF Founder and Board Chair.

How The Carbon Leadership Forum Began

KATE: The CLF began with a small group of people who were excited about understanding the carbon footprint of building materials. Usually that was one or two people in a single firm that were trying to advance this work. And so coming together in 2010 was a way of building community and sharing best practices.

The group had the goal of being able to get better data to inform decisions. And so early work was focused on advancing the standards for reporting the carbon footprint of materials, enabling people to pick lower-carbon options. Over time, we started conducting research on data and methods. But by 2020, it was still a relatively small group looking at embodied carbon.

That year we changed tactics, empowering more people to act by founding regional hubs. We also moved into engaging more explicitly with policy.

CHRIS: I’ve been involved in this with Kate since day one, and it was a lonely, small group, so that outreach has been important. The wider sustainability community began to recognize that embodied carbon was critical, especially around what we call the "time value" of carbon. That’s the idea that saving X amount of carbon emissions now is much more crucial than saving the same amount 40 years from now, when it's too little, too late. That’s been a fundamental driver. And the CLF instigated a lot of the communication about that.

Embodied Carbon Enters The Spotlight

AMY: I got involved with the CLF when Thornton Tomasetti joined in 2012, and the window of opportunity has been opening since then. Attention to climate change has increased as we’ve experienced more impacts. At the same time, there was an expanding community – of academics, government and people in the building sector – that was enabled by the CLF and the discussions it was holding. Industry groups started paying attention and certification programs began providing points for measuring and offsetting embodied carbon. And then tools were developed that enabled designers to take action.

AMANDA: Those tools enabled measuring. And measuring embodied carbon led to technological advancements when people realized that some materials have egregious impacts. We’re seeing so much innovation, spurred by a demand for improvement. We work a lot with concrete procurement, and there are so many interesting new materials. Embodied carbon is frequently synergistic with issues like material toxicity; something lower in embodied carbon is often also healthier.

AMY: Yes, there can be multiple benefits. And what I’m seeing now is the perfect storm. All the vectors are pointing toward change. There has been growing global attention to how embodied carbon affects climate change, and more owners and developers asking for embodied-carbon reduction.

CHRIS: We've been approaching a tipping point for a long time. And now I think Amy’s “perfect storm” is a Category 5 hurricane driven by multiple factors. In the U.S., commercial interest in embodied carbon is enormous. The big change is that it’s become a buying criterion, so material producers are going from trying to be “good” to having millions of dollars at stake. That commercial interest is driven by the Inflation Reduction Act, but also by big companies saying to suppliers, "We're not going to build unless you give us EPDs (environmental product declarations)." And in Europe, it’s more regulatory-driven, but it’s coming like a steamroller, slowly but on a massive scale.

AMANDA: The fact that we've gotten very good at cutting operational carbon helped create an opening for embodied carbon. Carbon reduction used to just be about the energy buildings consumed. But with improvements in operational carbon reduction, embodied carbon is a bigger piece of what’s left. The building sector is the largest consumer of industrial materials by mass. You see policy starting to pay attention as the relationship between industrial decarbonization and embodied carbon in buildings becomes clearer.

KATE: Embodied carbon is the "it" topic right now, like operational carbon was 15 years ago. And there will be another "it" topic in the future. So we need to make sure embodied carbon gets integrated into a holistic understanding of our building and construction decision-making process – along with healthy materials, operational carbon and equity in decision-making.

AMY: We're also finding that embodied carbon can be an entry point for other climate-action services, which is great for engineering firms that offer diversified services.

Structural engineers have really embraced their role in lowering embodied carbon, and part of that is because of the Structural Engineering Institute’s SE 2050 Commitment (SE2050), which started as a challenge within the CLF. In a few years, structural engineers have gone from not knowing what embodied carbon is to managing it as a standard part of what they do.

KATE: Amy, I’m very proud of the CLF’s role in SE2050. Thornton Tomasetti and Arup were tracking embodied carbon on projects, so they worked together with the CLF to figure out how more designers could do it consistently. Figuring out a shared method was a challenging effort. It was a breakthrough moment for the CLF to issue the challenge in 2019 and then bring it to the American Society of Civil Engineers’ Structural Engineering Institute group to adopt and implement. Today SE2050 has 140 firms – it’s just stunning.

AMY: And now the consideration of embodied carbon is moving into new disciplines. Transportation engineers, for example, may not be thinking about it as much as building designers, but new policies and regulations are leading them to ask, "What does this mean for us?" The focus on embodied carbon is also making sustainability a commonplace element in design. It’s not just the responsibility of the people called "sustainability professionals," but something everybody has a part in.

What’s Next For Embodied Carbon?

CHRIS: One of the new things driving change is the capital pouring into sustainability. Just a few years ago, a venture capitalist wouldn't touch sustainability, but now we see companies like Sublime Systems raising $40 million to scale up production of low-carbon cement. In America, money talks. They're not going to turn off that faucet, so we need faster change in building codes to allow these new materials to be adopted.

AMANDA: Right now at Lendlease, we're piloting the use of various new materials and processes. And there's a new kind of savvy among teams regarding data and understanding the context. Data transparency is something we can now expect, thanks to companies like yours, Chris, as well as the guidance of the CLF. We’ve been able to make decisions based on that trusted transparent data, and it’s very exciting that we can require that on all our projects.

AMY: Shining this light on materials has also been great for opening up other conversations about ethical supply and healthy materials. We're looking directly into what they’re made of, and how, and where. And we can think about how the decisions we make affect our project and our communities.

CHRIS: Another big change is that material producers are starting to see that environmental data is strategic. It's data they want for their investors, data they want to manage, so my clients are getting their IT departments involved. That’s another indication of how seriously material producers are taking embodied carbon and supply-chain reporting – looking at sustainability issues holistically, not just at one material level but through the entire supply chain.

AMANDA: In all the innovation happening in these new materials, we're challenging ourselves to marry a stringent reduction in embodied carbon with durability and traditional performance requirements. It's a high bar to check all those boxes.

CHRIS: The ACLCA (American Center for Life Cycle Assessment) is now talking about carbon not as an emission, but as a product that is being put back into materials to be sequestered. It's another sign of the shift that's taking place at a technical level, and we're hearing more about circularity.

KATE: Right now, the CLF is working on something called the ECHO Project. A group of organizations that were issuing embodied-carbon challenges or commitment programs (see sidebar) got together to align the way people do the calculations and report results. What's particularly compelling to me about the group is its cross-sectorial collaboration. We've got engineers and architects and landscape architects. I don't know if there's any other place where that diversity of industry organizations come together.

The idea is that, for example, SE2050 reports the same fields as Architecture2030. Some of it is simple, like how do you categorize the type of building? How do you define floor area? But then it goes into embodied carbon details. What's the minimum amount of data you need to collect? How do you calculate it? Those sorts of things. So when a developer says, "Do embodied carbon," the whole project team knows what that means and how to accurately count their individual pieces.

AMY: It’s a great initiative. At Thornton Tomasetti we're reporting to SE2050 and we're also a member of the AIA 2030 Commitment. Right now, it’s all different, so hopefully it'll become much easier with the ECHO project.

KATE: The rise of embodied-carbon tracking right now is about shifting design and construction as well as industrial practices. Reusing more buildings, reusing materials, using materials more efficiently. How do we make materials? Can we grow cement instead of calcinating limestone? We're at an interesting place, thinking about radically new materials or modifications of existing materials.

The Future Of Embodied Carbon, And Beyond

CHRIS: Looking to the future, you have to be optimistic. Fifteen years ago, the possibility that embodied-carbon action could be where it is today would have been inconceivable. There were 10 people in the room. And look how far we’ve come. So imagine what could happen in 15 more years.

AMY: I’m also seeing a shift in focus beginning, from carbon footprint to carbon handprint. From just trying to reduce the harm we do to taking actions that are net-positive. How can we use our ingenuity and innovation to help make these transformations happen?

KATE: I'd like to extend the timeframe of our thinking. I’ve been focused on the 2030 to 2050 timeframe, on meeting those global climate targets. But there's also a much longer view: what do we expect the building industry to be like 100 years from now? 200? 1,000? If we want a thriving, healthy world, we can't be just an extractive economy. We have to move towards circular and sustainable systems. There's a whole transformation that needs to take place. And to me, that is exciting and inspiring.

AMANDA: In the context of that thousand-year horizon, I’m always inspired by places like the Pantheon in Rome. It was built of concrete 2,000 years ago and it’s one of the most beautiful structures in the world. And they built that without the technology and tools and resources that we have now. We need to hold ourselves to those standards of beauty and durability to meet the urgent challenge that we have on our hands. Luckily, there are a lot of incredibly smart people focused on it. And so I’m optimistic.

CHRIS: There's clearly a path to regenerative materials – to a regenerative world – that's feasible. I don't know the exact steps, but there's so much momentum. There's a very positive potential, if we can do it fast enough.

Interested in hearing about how to lower the embodied carbon in buildings? Check out our series of brief podcasts on practical strategies designers can use now.
Learn more about how Thornton Tomasetti is collaborating with project partners to find the best path in our 2023/2024 Annual Review.