Contract documents

September 30, 2023

What is Embodied Carbon and why is it important to sustainability?

The building design and construction sectors are significant contributors to carbon emissions – at least 39% globally. As operational building efficiency continues to improve, embodied carbon is becoming an increasingly important part of the climate conversation.

Embodied carbon refers to  all of the carbon that is expended to manufacture, transport and install construction materials, and includes the carbon associated with the project’s end of life.  It is called “embodied” because this carbon is “locked in” once the building is built – once this carbon is expended, its environmental impacts are established and it is forever a part of the building.

Put another way, operational efficiency is only part of the puzzle; embodied carbon is everything else.   As building operations become more efficient, embodied carbon will become a larger percentage of the building sectors’ total emissions.  Additionally, most embodied emissions are front-loaded in a project’s lifecycle; by implementing strategies to reduce embodied carbon today, we are working in this critical time when we still have an opportunity to act.  These, and other reasons, are why regulatory bodies have increasingly focused on embodied carbon as a way to mitigate climate change and as a pathway to meet climate action goals.

New regulations provide a framework for risk management

There are various regulations addressing embodied carbon, which means it is important for designers, contractors and other building industry professionals to be aware of this evolving landscape.  While California is certainly not the only jurisdiction working in the embodied carbon space, California’s leadership with respect to embodied carbon presents a good case study of what the future may look like.

Buy Clean Legislation

One strategy for addressing embodied carbon is what is known as “Buy Clean” policies and programs.  These generally are procurement policies that establish requirements for government purchasing, with a focus on construction materials that reduce embodied carbon emissions, among other things.  Buy Clean policies tend to focus on materials with the highest embodied carbon impacts:  concrete, steel and aluminum, which combine for 23% of total global emissions.  Buy Clean policies are a helpful tool not only because they directly reduce the amount of carbon in construction materials, but also because they help create and support development of a competitive market for lower embodied carbon products.

One example is the Buy Clean California Act, AB 262 (2017), which, among other things, originally required certain public projects to gather and disclose emissions data by producing facility-specific Environmental Product Declarations (EPDs) for high embodied carbon products.  There are other facets to AB 262, and other jurisdictions, including the Federal Government, which have implemented Buy Clean policies.

Establishing Embodied Carbon Limits

More recently, AB 2446, Carbon Intensity of Construction and Building Materials Act (2022), builds on California’s Buy Clean legislation by, among other things, requiring the California Air Resources Board to develop a framework for reducing the average carbon intensity of various building materials to specific levels.  The Carbon Intensity legislation also requires projects over a certain size to submit life cycle assessments and manufacturers to submit EPDs.

Embodied Carbon in the Building Code

Continuing this trend, in August 2023, California adopted building code changes that are expected to significantly reduce embodied carbon in that state.  According to the New Buildings Institute, “California is now the first state in the nation to address embodied carbon on public and private buildings larger than 100,000 square feet, and schools larger than 50,000 square feet….”   The code changes build on the Buy Clean California Act, and provide flexibility by allowing for three different compliance pathways to comply:  building reuse, prescriptive emission limits, and modeled reductions using lifecycle analysis.

New tools and opportunities to educate teams and manage risk

The cadence of legislation in California presents a case study for what practitioners in other jurisdictions might expect.   And with all the new legislation in this area, it is important to keep updated on the latest requirements.

To support practitioners, industry-driven tools are also emerging.  For example, organizations like the Rocky Mountain Institute have prepared resource libraries related to embodied carbon legislation.  And tools such as the Embodied Carbon in Construction Calculator (EC3) “a free and easy-to-use tool that allows benchmarking, assessment and reductions in embodied carbon, focused on the upfront supply chain emissions of construction materials,” are also available.

Nicole DeNamur is an attorney and sustainability consultant, based in Seattle, WA.  Her company, Sustainable Strategies, helps clients identify and manage the risks of sustainable innovation so they can pursue robust sustainability goals.  She is also an award-winning contributing author and has developed and taught graduate-level courses at the University of Washington and Boston Architectural College. Nicole was named Educator of the Year by the International WELL Building Institute, and Sustainable Strategies hosts an online course, Accelerated WELL AP Exam Prep.

AIA Contract Documents has provided this article for general informational purposes only. The information provided is not legal opinion or legal advice and does not create an attorney-client relationship of any kind. This article is also not intended to provide guidance as to how project parties should interpret their specific contracts or resolve contract disputes, as those decisions will need to be made in consultation with legal counsel, insurance counsel, and other professionals, and based upon a multitude of factors.