In 2008, architect Larry Strain, FAIA, was part of a team designing a town center in Portola Valley, California, when he conducted a Life Cycle Assessment (LCA) and made a surprising discovery—embodied carbon accounted for half the carbon emissions from his project. “At the time, buildings were getting more efficient, so I’d started to pay more attention to embodied carbon,” Strain says. “But when we calculated the project’s emissions for the next 20 years, I was shocked to discover that half the amount was embodied. It changed the whole conversation.”
Strain, a principal at Siegel & Strain Architects in Emeryville, California, decided to dig deeper. Founded in 1964 by open-space activists, Portola Valley has long been a progressive community and wanted to create a new town center that restored the land’s natural habitat with a low environmental footprint. Like many architects, Strain believed that a building’s embodied carbon wasn’t as important as its operational carbon. But after calculating the project’s emissions from site work, daily transportation for workers, and materials—including special-order windows from Manitoba, Canada—he realized that half the project’s overall carbon emissions for the next two decades would be from the embodied carbon of its building materials—creating a major impact at a crucial time for climate change.
“Over the next 100 years, the embodied carbon of the town center will account for only 13% of the total project carbon,” Strain says. “But the immediate years were the eye-opener. As an architect, I realized the first and most dominant emissions from our buildings are embodied. And at this point, we only have about 10 years to solve climate change—so we’d better address embodied carbon now.”
Architecture firms of all sizes are increasingly using online resources to quantify one of the greatest challenges of our era: Embodied carbon. For years, architects have focused on reducing operational carbon, the carbon dioxide (CO2) emitted by buildings as they operate. Embodied carbon, by contrast, is the CO2 released during the construction of a building (including extracting, transporting, and manufacturing materials) and is even more of a pressing demand. Overall, building operations, materials, and the construction sector contribute a combined 39% of worldwide carbon emissions. Of that amount, embodied carbon will be responsible for 72% of all CO2 emissions of new buildings constructed in the next 10 years. Compared with operational carbon—which will account for about 28% of all CO2 emissions of the buildings constructed during those years. The embodied carbon of concrete, steel, and aluminum alone accounts for 22.7% of global CO2 emissions, and most of it is from buildings and infrastructure construction.
For architects, embodied carbon is crucial to consider. Unlike operational carbon, which can be reduced during a building’s lifetime, embodied carbon is emitted at the beginning of a building’s life. It can never be recaptured. And while the climate change discussion in architecture has long been about reducing energy, that does not always equate to reducing environmental impact.
To make an impact, architects need to build a new vocabulary for tactics around designing buildings that actually help reduce both operational and embodied carbon. And they need to do it quickly—there’s no luxury of time to repeat the mistakes of the past.
Fortunately, tools that measure embodied carbon offer a new way forward.
Although embodied carbon is difficult to quantify and track, architects in firms of all sizes are working to reduce it with digital resources that pull from various sources to help stop climate change. (All the online resources listed in this article can be used by firms of all sizes to reduce embodied carbon.)
“These tools help us understand just how much we’ve been undercounting embodied carbon,” Strain says. “And they can really help us bring that number down.”
Identifying Embodied Carbon
There are three main ways that embodied carbon is quantified and shared.
1. Life Cycle Assessments: LCA tools are software programs, standards, and guidance documents. They are one of the best mechanisms for architects and other building professionals to understand the energy use and other environmental impacts associated with all the phases of a building’s life cycle: manufacturing, construction and transportation, use, end of life, and material recovery.
2. Environmental Product Declarations: An Environmental Product Declaration (EPD) is an independently verified and registered document that communicates transparent and comparable information about the life-cycle environmental impact of products, including carbon emissions (also referred to as global warming potential). The EPD is based on Product Category Rules (PCR), which define the parameters and boundaries of what is being studied.
3. Online Resources for Reducing Embodied Carbon: These are software programs and resources that enable architects to calculate the embodied carbon of proposed projects—and then help them discover ways to reduce it.
Small firms (typically up to nine staff) have many options for reducing their embodied carbon. The easiest method is to work with suppliers who use Environmental Product Declarations (EPDs), labels that state independently verified information about the carbon footprint of each product, similar to a nutrition label.
For projects like two-story multifamily buildings, small firms can use online tools like the Embodied Carbon in Construction Calculator (EC3) tool, a free open-access application that helps architects source materials with low embodied carbon in categories like concrete, insulation, gypsum board, and carpet. Architects can use it to find low-carbon products like concrete mixes that have CarbonCure—recycled CO2 that is injected into the concrete mix to strengthen it and store carbon—sheep’s wool for carpeting, and straw bales for insulation. And, for larger projects, small firms can work as advisors, partnering with other firms to use EC3 to sort and visualize supply-chain–specific carbon emission data, set targets and specifications for materials and projects, and view digitized industry-average and industry-specific EPDs.
“With embodied carbon, it’s important that architects share information,” says Ralph Bicknese, AIA, the co-founder of Hellmuth + Bicknese Architects in St. Louis, a five-person firm known for sustainable projects across the United States. “The main things we look at to reduce embodied carbon is materials for the building structure, envelope, and finish—and we collaborate with structural engineers, construction managers, and suppliers to get it done. We also work with different teams on sustainability projects for clients like Washington University over and over again. There’s a lot of opportunity for crowdsourcing, and demand is growing because people are catching on that these things are important, even here in the Midwest.”
Medium-sized firms (typically 10-49 people) can lower embodied carbon on large commercial projects. The manufacture of core construction materials like steel, concrete, aluminum, and glass account for 11% of global CO2 emissions. By focusing on how to reduce the embodied carbon of these materials in commercial construction, medium-sized firms can reduce environmental impact in a significant way, often without increasing the budget.
In addition to tools like EC3, firms like Siegel & Strain architects—which has 19 employees and works on sustainable commercial projects—use the Inventory of Carbon & Energy (ICE) Database, a free online resource with information about the embodied carbon of more than 200 materials. Unlike other resources, the ICE Database doesn’t do calculations for you, making it an ideal entry point for learning about embodied carbon.
“It’s more of a blunt instrument that just gives you the carbon impact of materials,” Strain says. “So, I like using it in conjunction with other tools because it gives you a real sense of the carbon footprint of every material and helps you learn about things on a broad scale. In addition to learning about materials like concrete, you start to realize how other materials, like gyp board and insulation, can also add up in terms of carbon footprint.”
Finally, large firms (typically 50+ people) can perhaps make the biggest impact to reduce embodied carbon in the fastest amount of time. Today corporations are increasingly making commitments to reduce their carbon footprint. Microsoft even pledged to go “carbon negative” by 2030, meaning it will take more carbon out of the air than its supply chain and operations produce—a perfect project for a tool called Tally.
Created by KieranTimberlake—a 90-person firm in Philadelphia with sustainable projects across the globe—the online application Tally is used by architects to quantify the complete LCAs of even the largest projects. KieranTimberlake is even aiming to use it to influence governments and society at large to reduce their environmental impact, leading to true change for the future. “Tally allows architects to calculate their environmental impact, including their embodied carbon, as they’re designing in Revit,” says Billie Faircloth, AIA, a partner and research director at KieranTimberlake. “It basically puts life cycle assessment into the hands of designers and integrates it into their design process—making reducing carbon a more seamless procedure.”
Resources to track and reduce embodied carbon are putting the power to reduce carbon emissions and make real change in the hands of architects, from solo practitioners to international firms—creating a collective power to change the world unlike any other profession.
“The first thing we need to address in each project is embodied carbon,” Strain says. “Using these tools, I can reduce my carbon footprint by 50 percent pretty easily just by picking better materials. Going forward, climate’s the most important issue we’re facing, and we can use tools like this to shift things quickly—I’m feeling really encouraged.”
8 Resources for Reducing Embodied Carbon
AIA Framework for Design Excellence. The framework is made up of 10 measures. Each dimension provides an in-depth exploration, including best practices, high-impact strategies, resources, and case studies that promote climate action.
Architecture 2030 Carbon Smart Materials Palette. The 2030 Palette is a free online platform that curates information and practices to provide guiding principles for creating low-carbon buildings.
Athena Sustainable Materials Institute’s Impact Estimator for Buildings. An LCA-based software package that lets architects, engineers, and analysts explore the carbon footprints of different material and system options.
Beacon. An open-source Revit plug-in for structural engineers that generates a data visualization of a project’s embodied carbon, Beacon presents the embodied carbon by material type, building element, and floor levels, allowing engineers to know where to minimize it.
EC3 by Building Transparency. The Embodied Carbon in Construction Calculator (EC3) is a free tool that enables architects to find and compare products in order to source low-carbon options available for purchase in their region. It also lets them plan and compare buildings by entering project material quantities to benchmark, set, and realize project-specific embodied carbon reduction targets.
ICE Database. The Inventory of Carbon & Energy Database is a free online resource with information about the embodied carbon of more than 200 materials. Users can download the database, which is updated regularly, and then research over 30 main categories to calculate the embodied carbon of materials including metals, plastic, and concrete.
LCA Practice Guide. The Life Cycle Assessment guide explains how to calculate the environmental impacts associated with all stages of the construction of a building, from sourcing the raw materials to its daily operation once completed. The guide explains the concepts, actions, and milestones for reducing impact.
Tally. A plug-in application for Autodesk Revit that can perform an LCA on demand during the initial design phase, Tally offers three types of analysis: Whole building LCA, design-option comparison, and material selection.
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