Reducing Embodied Carbon on the Path to Zero Carbon Buildings

This blog was written by Patrick Ford, Director, Circular Economy at Legrand, North and Central America.

Wherever you are reading this, take a minute to look around your space. Chances are, if you were to think about the carbon emissions related to the room you’re in, your mind likely goes first to energy use and behavior – such as the decisions you make throughout the day to turn off the lights, adjust the thermostat, or perhaps power down your laptop.

If you are sitting in a high-performance building, many of those energy related decisions are being made for you via interconnected systems designed and installed by architects, specifiers, contractors, and others, with the goal of ensuring that the building is operating as efficiently as possible throughout the day.

You may not have thought about carbon in terms of the products that compose these building systems, nor of all the structural and finish materials that sit above, below, and around you. But it’s there.

The carbon that is emitted during the extraction of those materials, the manufacturing of those products, their transportation to the job site, their installation and required maintenance, and their end-of-life processing is known as embodied carbon, and it currently accounts for approximately 11% of global GHG emissions.

Architecture 2030 estimates that between now and 2050, embodied carbon will account for nearly 50% of emissions from new construction buildings, and unlike operational carbon emissions, this carbon can’t be reduced when a product is installed.

Many of these carbon-intensive materials originate from a linear, or take-make-dispose economy, as evidenced by the 2021 Circularity Gap Report published by Circle Economy, which estimated that the global economy is only approximately 8.6% circular. This presents a significant opportunity to reduce embodied carbon in the built environment by accelerating the transition to a circular economy through designing out waste in construction and building materials, keeping building products in use for longer, and designing with low carbon, healthy building materials.

Knowing all of this, what tools exist today to measure and reduce embodied carbon?

We don’t have space in this article to explore each tool in depth, but here are some key categories of tools that can and are helping to move the needle with respect to embodied carbon in buildings.

Product-Level Measurement and Reduction. Embodied carbon accounting starts at the material and/or product level with the development of the life cycle assessments (LCAs), and the publication of environmental product declarations (EPDs) based on the LCA data. An EPD discloses the global warming potential (GWP) along with environmental impacts, of a product, and must be independently verified. Having an EPD does not mean that a product has low embodied carbon, but manufacturers can leverage the associated LCA data to identify opportunities for reduction.

Building-Level Measurement and Reduction. Once an LCA is completed, that data can be used to inform embodied carbon measurement and reduction efforts at the building level, either through whole building LCA (WBLCA) tools or material procurement tools. Examples of WBLCA tools include Tally, One Click LCA, and the Athena Impact Estimator, and an example procurement tool/database that leverages EPDs is the Embodied Carbon in Construction Calculator (EC3).

Policies & Standards. A June blog post by Webly Bowles, Project Manager, NBI, covered both material-based and whole-building LCA policies, so I encourage you to check that out to learn more. NBI also maintains the Getting to Zero Resource Hub with a page dedicated to embodied carbon, including a section on rules and standards which covers “standards for construction projects to measure, select, and report life cycle analysis, including global warming potential/embodied carbon.”

Green Building Rating Systems. The United States Green Building Council’s (USGBC) LEED v4.1 and the International Living Future Institute’s (ILFI) Living Building Challenge (LBC) 4.0 and Zero Carbon Certification all address embodied carbon utilizing a range of methods, including the establishment of baselines, whole building carbon reductions, and product-specific carbon reductions.

Additional information about USGBC’s efforts to address embodied carbon in LEED v4.1 can be found in this article, and in late 2019, they published a Procurement of Low Carbon Construction Materials pilot credit with the goal of “improving the data and comparability of data from life cycle assessment (LCA) results.”

ILFI’s LBC 4.0 addresses embodied carbon within Imperative 7, Energy + Carbon Reduction, and Imperative 8, Net Positive Carbon, of the Energy Petal, requiring a 20% reduction in the embodied carbon of primary materials, and the use of carbon-sequestering materials and/or a one-time carbon offset purchase to account for the total embodied carbon emissions from construction. In addition to this, their Zero Carbon Certification requires project teams to calculate the building’s embodied carbon, reduce it as compared to a baseline scenario (total embodied carbon emissions can’t exceed 500 kg-CO­­2e/m2), and offset the rest.

I have a lot on my plate already, what is one step I can take to address embodied carbon in my life today?

Given the urgency of the climate crisis, everyone can play a role in cutting emissions, even if you don’t focus on sustainability full time. Here are a couple ways that you can kick off or accelerate your own efforts.

Learn more. Visit the Getting to Zero Resource Hub and the Carbon Leadership Forum’s Resource Library to learn more about embodied carbon.

Take action. If you are an owner, construction manager, sustainability consultant, architect, structural engineer, or general contractor,  check out Building Transparency’s new Embodied Carbon Action Plan for steps you can take to address embodied carbon in the design, preconstruction, construction, operations, and deconstruction phases of a building’s lifecycle. There are a number of other great resources to check out, including Perkins & Will’s Embodied Carbon in the Built Environment primer and RMI’s Reducing Embodied Carbon in Buildings report.

Last, but not least, be sure to attend the embodied carbon sessions at the upcoming Getting to Zero Forum on Thursday, October 28th to hear directly from leaders on strategies for addressing embodied carbon.