What is embodied carbon?

All phases of building construction produce greenhouse gas emissions: the production of building materials, the actual assembly of the structure, the use phase via the consumption of energy, and finally demolition and material end-of-life or recycling. Embodied carbon refers to the greenhouse gas emissions arising from the manufacturing, transportation, installation, maintenance, and disposal of building materials. In contrast, operational carbon refers to the greenhouse gas emissions due to building energy consumption.

For building materials, the initial embodied carbon includes the extraction and transportation of raw materials and manufacturing of the final product. For buildings, it includes the emissions embodied in materials, as well as transportation to the site and the actual construction process. Unlike operational carbon, there is no opportunity to reduce the initial embodied carbon of materials with updates to efficiency to the building. Therefore, there is an urgent movement to address it as a significant percentage of global emissions.

This database organizes state and local legislation which seek to regulate initial embodied carbon in concrete. It includes legislation that has been passed into law, legislation that is currently being considered by state legislatures, and legislation that failed to pass. Use this database to monitor in-process legislation and compare it to successful and unsuccessful versions in other states and localities.

Most of this legislation applies to state- and local-government-funded building and/or pavement projects, and aims to require Environmental Product Declarations (EPDs) during the bid or construction process. EPDs report multiple environmental impacts, but embodied carbon (measured as kg of CO2e) is considered the most significant in light of climate change. These are often called “Buy Clean” policies after the 2017 Buy Clean California Act, included below. They typically require construction materials to meet or fall short of an embodied carbon limit (or baseline) based on predetermined average, which is adjusted down over time to reflect improvements in the industry.

There is a wide variety in embodied carbon policies. Below is a small selection of the ways in which they can vary:
• Embodied carbon limits. Different embodied carbon bills derive their maximum limits from different data sets and methods and have different review periods.
• Timing of EPD reporting. Some bills require EPDs to be submitted as part of the bid, others before installation of materials.
• Scope of eligible materials. Some bills include concrete alongside comparable materials such as steel and engineered wood. Others include a more limited set of materials or apply to concrete or cement alone.
• Size of eligible projects. These bills usually include either a minimum amount of concrete (in cubic yards), or minimum total square footage of the building project, before EPD reporting is required.
• Completeness of policy. Some bills only require reporting of embodied carbon but leave limits to be established by future legislation or regulation. Others are limited in scope to pilot programs.

Local Embodied Carbon Legislation

In addition to state laws, county- and municipal-level ordinances also regulate embodied carbon in building materials.

• Berkeley, CA: Green Code

• Marin County, CA: Low Carbon Concrete Code

• Portland, OR: Low-Carbon Concrete Purchasing Program

• Hastings-on-the-Hudson, NY: Resolution for Low-Embodied Carbon Concrete for Building and Infrastructure Projects

• Austin, TX
  o Climate Equity Action Plan
  o Austin Energy Green Building

• Langford, BC, Canada: Low Carbon Concrete Policy