California Embodied Carbon Legislation: How to Prepare for AB 2446

Subscribe to Stok Insights
California Embodied Carbon Legislation: How to Prepare for AB 2446

Some exciting news coming out of California means big things for Life Cycle Assessments (LCAs), which analyze a product’s full life cycle environmental impacts and identify prioritized areas for carbon reduction. As building decarbonization continues to be an increasing priority at the state level, there’s building momentum for low-carbon construction materials to go mainstream. With California’s climate leadership only growing, this new bill paves the way for renewed focus on embodied carbon reduction across the building sector.

Here we give you the highlights of the new legislation, takeaways from a recent study and new tool for embodied carbon policy reduction, how this may impact the development landscape in California and beyond, and what you can do to prepare for it.


AB 2446 (“Embodied carbon emissions: construction materials”) sets the stage for widespread and accelerated embodied carbon reduction across California. The bill requires the state to develop a “framework for measuring and then reducing the average carbon intensity of the materials used in the construction of new buildings,” including a comprehensive strategy to reduce California’s building sector’s greenhouse gas emissions by 20% by 2030 and by 40% by 2035.

The bill also requires the State Air Resources Board to encourage the production and use of low-carbon construction materials, leveraging state and federal financial incentives where possible to drive market demand. These materials can significantly lower the greenhouse gas emissions associated with a product or project without increasing the cost to the owner.

This is big news for low-carbon construction materials! With the state’s leadership, low-carbon materials will be incentivized to reduce embodied carbon across the building sector. Carbon Leadership Forum (CLF) dives deeper in its embodied carbon policy educational series.


Realizing the growing city commitments to carbon reduction, CLF is developing an embodied carbon policy reduction calculator to aid policymakers in setting ambitious and achievable carbon reduction targets at the city level. It’s currently in the early development stages, with a proof-of-concept calculator and a pilot study applying reduction scenarios to three cities: New York City, Portland, and Austin. For each city, the team identified a baseline scenario of total embodied carbon by 2050, as well as 3-6 reduction scenarios depending on the policy type.

The initial findings are:

  1. The most impactful policies required reductions in whole building embodied carbon
  2. The next most impactful policies incentivized adaptive reuse
  3. The third most impactful policies focused on low-carbon concrete and housing size

While there is still much work to be done, the results from this proof-of-concept study demonstrate exciting potential for these calculators to enable policymakers to take a data-driven approach to advocating for the most impactful achievable policy solutions that align with their cities’ goals.


AB 2446 will have a large impact on developers and the development landscape in California and beyond. As a starting point, here’s what developers should consider when preparing for the new legislation.

Considerations for Developers

#1: Utilize existing resources

There are several strategies and tools to reduce embodied carbon emissions without increasing overall project cost at all stages of the project. Adaptive reuse, building mass reduction/optimization, and material efficiency can significantly reduce upfront carbon emissions during early design. As the project progresses, whole building LCA, identification of carbon hotspots, and procurement of low carbon materials can help further reduce carbon impacts. Available embodied carbon resources are listed in the AIA-CLF Embodied Carbon Toolkit.

#2: Identify synergies with other policies and green building certifications

The Buy Clean California Act (BCCA), LEED v4.1 Material Life Cycle Impact Reduction credit, and Living Building Challenge Material Embodied Carbon imperative all target embodied carbon of building materials. By understanding these synergies, developers can streamline their efforts to achieve multiple targets.

#3: Collaborate early with industry stakeholders

Decisions of owners, designers, engineers, contractors, suppliers, and even researchers can highly impact embodied carbon of buildings at various stages of the project. Hence, improved collaboration with all stakeholders and early buy-in can enable better understanding and implementation of carbon reduction strategies.

Impact on Development Landscape in California

#1: Accelerate the adoption of alternate building systems and materials

The new legislation is likely to accelerate the shift from conventional carbon intensive structural systems and assemblies such as concrete, to low carbon alternatives such as mass timber, recycled steel, and composite systems. It will also encourage innovation and introduction of net carbon sequestering materials such as hempcrete and cellulose as a substitute to phase out its carbon intensive counterparts like closed cell spray foam insulation.

#2: Increase adaptive reuse

Compared to new construction, adaptive reuse of existing buildings can save up to 75% of embodied carbon emissions. This bill could catalyze an increase in renovation projects, and the site selection process is likely to consider more existing buildings that can be potentially restored.

#3: Expand available product-specific Environmental Product Declarations (EPDs)

Financial incentives and regulations encouraging the roll out of low carbon materials and requirement of whole building LCAs will encourage more suppliers to publish product specific EPDs. This will improve the data quality of LCAs as well as reduce overall carbon emissions of building materials.

Whether you’re ready for the new legislation to go into effect or unsure where to start, we’d love to discuss your opportunities for embodied carbon reduction. Reach out to connect.