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Regulating Embodied Carbon in Construction: Lessons from California

Mantle Developments has examined California’s pioneering approach to regulating embodied carbon in construction and explores potential lessons for Ontario in embodied carbon regulation.

Keywords: Embodied carbon, net-zero emissions, life-cycle assessment, decarbonization, embodied carbon management.

In August 2023, California became the first state in the US to require measures to reduce embodied carbon in certain types of building construction. The world’s fifth-largest economy plans to limit embodied carbon emissions associated with the construction of new commercial and school buildings as of July 1, 2024. These changes – voted into effect by the California Building Standards Commission (CBSC) – have been driven by concerns about the embodied carbon emissions resulting from building construction. 

California’s new embodied carbon regulation at a glance:

  • This change is an update to the 2022 California Green Building Standards Code (CALGreen), which was first introduced in 2007.
  • The updated code targets commercial buildings larger than 100,000 square feet (~9,290 m2)  and schools over 50,000 square feet (~4,645 m2).
  • The code offers three compliance paths for reducing carbon emissions in construction:
    • Reuse: reusing 45% of an existing structure, 
    • Prescriptive: using low-carbon materials below specific emission intensity limits, or 
    • Performance: whole building life cycle assessment (WBLCA) analysis that demonstrates a 10% reduction in embodied carbon emissions below a baseline building.
  • The changes will be effective from July 1st, 2024. AIA California plans to educate building professionals about these updates through seminars.

Embodied Carbon Management North of the Border

As Mantle Developments reported previously, in May 2023, Toronto became the first jurisdiction in North America to explicitly mandate lower embodied carbon emissions in future construction projects as a component of the Toronto Green Standards (TGS) v4 update. 

At the federal level in Canada, existing regulations surrounding embodied carbon are mandated in the Standard on Embodied Carbon, an initiative spearheaded by the Treasury Board Secretariat’s Centre for Greening Government. This new standard, which came into effect on December 31, 2022, and falls under the Centre’s Policy on Green Procurement, stipulates that entities bidding on construction tenders must disclose the embodied carbon intensity of ready mix concrete used in the project through an environmental product declaration (EPD), which must demonstrate a global warming potential (GWP) of at least 10% below a baseline value. This standard currently applies to construction projects involving funding from the federal government. 

With the City of Toronto making profound strides at the municipal level, California implementing embodied carbon regulations at the state level, and the Government of Canada providing leadership at the federal level (to name but a few of North America’s embodied carbon policy leaders), it is somewhat surprising that Ontario has yet to follow suit at the provincial level, as there are currently no provincial regulations surrounding embodied carbon. 

There are Sustainable Design Standards mandated by Metrolinx (the Crown agency of the Government of Ontario that manages and integrates road and public transport in the Greater Toronto and Hamilton Area) which stipulate that projects over $30 million must perform a life-cycle assessment (LCA) and report their results, there are currently no performance requirements, targets, or caps on embodied carbon.

Ontario should take inspiration from California and implement embodied carbon regulations at the provincial level. Federal regulations codified at the national level, in tandem with the precedent set by the Toronto Green Standard (TGS) v4, can help guide the province’s implementation of low-carbon construction regulations. The California example shows how Ontario can integrate embodied carbon regulations into a broader provincial strategy to address climate change and be a key player in the embodied carbon space in North America’s transition to net zero.

Key Takeaways and Lessons from California:

  • Industry Stakeholder Collaboration and Engagement: one of the most striking features of California’s new embodied carbon legislation is the collaboration between the state and professional industry bodies. California worked closely with the California chapter of the American Institute of Architects in crafting the legislation. 

Ontario could replicate this by formally engaging with associations such as Professional Engineers Ontario (PEO) and the Ontario Association of Architects (OAA) in drafting future embodied carbon legislation. This approach would help ensure that regulations are pragmatic, achievable, and have the backing of industry.

  • Phased Implementation: Another prominent feature of California’s new regulations is that the implementation takes a phased, gradual approach and initially targets larger commercial and school buildings. 

Ontario could take a similar approach and target commercial and school buildings first, before gradually phasing in residential buildings. California’s example of phased implementation shows how embodied carbon reduction need not start by adding additional requirements to housing. By targeting commercial buildings and schools first, the province could demonstrate leadership and get the building industry ‘up to speed’ on low-carbon materials without impacting critically needed housing expansion plans. 

Eventually, embodied carbon regulation should go beyond public, commercial, and residential buildings to eventually include all types of construction including infrastructure such as roads, sewers, bridges, airports, and ports. 

  • Utilizing Existing Framework: Ontario does not need to start from scratch. It could adopt existing municipal and federal embodied carbon policies and phase them in provincially by incorporating them into its existing Made-in-Ontario Environment Plan– a plan that looks to decarbonize the province by reducing its carbon dioxide (CO2) equivalent emissions by 30% below 2005 levels by 2030 (this target aligns Ontario with Canada’s 2030 target under the Paris Agreement).
  • Regulatory Flexibility: Another key characteristic of California’s new regulatory framework is the degree of flexibility it allows industry professionals to implement the new codes. There are three different compliance pathways permitted. The multi-faceted approach affords construction stakeholders with flexibility to pursue the most feasible pathway for their projects. Ontario could adopt a similar approach that would cater to the diverse nature of construction projects in the province.

Jurisdictions like California and Toronto are redefining North American sustainable construction practices. Ontario has an opportunity to champion embodied carbon regulations at the provincial level. Drawing from the California experience, Ontario can implement a framework that fosters industry collaboration, can be implemented in phased approaches, capitalizes on pre-existing regulations, and offers regulatory flexibility. As the largest provincial economy in Canada, Ontario is well poised to take on a leading role in Canada’s shift towards net-zero emissions in construction through creating thoughtful embodied carbon policy.

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