COP28 Report from Lauren Alger:
In the urgent pursuit to reduce global emissions, design professionals are collaborating to decrease the built environment’s negative impacts, which have accounted for a staggering 42% of the world’s annual carbon footprint. Approximately 27% of these emissions originate from building operations, while the remaining 15% are embodied carbon emissions from construction materials for both buildings and infrastructure systems. While policies continue to emerge which rightfully prioritize reductions across operational emissions of buildings, the impacts associated with our construction materials and infrastructure systems require further attention.
Construction Materials
Embodied carbon encompasses the emissions generated across a material’s entire life cycle, from production through transportation, construction, maintenance, and repair, to the eventual demolition and disposal or reuse. Typically, a single manufacturer can estimate the emissions generated by a material during its production phase, covering raw material extraction, transportation to the manufacturing facility, and the manufacturing process itself. Notable progress has been made in collecting and analyzing material-specific emissions data, evident in resources like Building Transparency’s EC3 database and the Carbon Leadership Forum’s North American Material Baselines Report. These resources provide crucial estimates for comparing material emissions values.
Embodied Carbon Across Building Systems
Beyond the material production phase, the emissions generated during the remaining life cycle phases hinge on factors like the building or infrastructure type, proposed design and construction methods, maintenance and repair efforts, and eventual demolition and disposal or adaptive reuse. Various industry initiatives, such as SE 2050, Architecture 2030, AIA 2030, and MEP 2040, have accelerated research and provided valuable resources to reduce embodied carbon within structures, enclosures, and mechanical, electrical, and plumbing (MEP) systems of buildings. Similarly, Climate Positive Design’s Pathfinder tool estimates the emitted and sequestered carbon associated with landscaping designs. By providing free tools such as carbon estimators and best practices for designs and specifications, multidisciplinary building and landscape designers can access the resources collected and provided by these groups to make more carbon conscious design decisions.
Call to Action: Opportunities for Infrastructure
While significant progress has been made to evaluate embodied carbon within building systems and construction materials, infrastructure systems remain less widely studied. Embodied carbon emissions for bridges, tunnels, roadways, highways, runways, seaports, and other infrastructure systems significantly differ from building systems. The lack of robust industry data and infrastructure system baselines stems from absent system-level embodied carbon methodologies. Global research efforts, particularly in bridges and microtunneling, present opportunities for the industry to develop system-level methodologies for individual projects. As bridge design professionals develop and publish life cycle assessment methodology guidance, projects can test the proposed guidance and provide feedback for further refinement and standardization. Additionally, the Institute for Sustainable Infrastructure’s Envision framework provides guidance to calculate embodied and operational carbon emissions associated with a project. Just as life cycle assessment tools for buildings and materials are being integrated into modeling software for design professionals, future standardized carbon calculations for infrastructure systems can be integrated as well. This will allow design professionals to compute a project’s holistic carbon footprint more easily at various design stages and make informed, environmentally conscious engineering decisions early in the design process.
Envisioning our Future
The development and standardization of embodied carbon calculation methodologies for infrastructure systems can be accelerated through multidisciplinary collaboration. In the U.S., members of the American Society of Civil Engineers (ASCE) have launched Infrastructure 2050 to centralize and distribute knowledge surrounding infrastructure best practices and proposed methodologies. As the industry strives to build and maintain essential public infrastructure globally, we have the opportunity to incorporate more environmentally conscious design decisions and reduce emissions within our communities.
Lauren Alger, PE, ENV SP, is Director of Sustainable Design at STV and is Chair and Co-Founder of Infrastructure2050.
