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Embodied carbon reduction roadmap Strategies and policies for the state of California September 2023 Contents Appendix C51 Executive summary Executive summary The carbon emissions associated with materials usedin the built environment, referred to as “embodiedcarbon,” are estimated to contribute to 11% of allglobal energy-related carbon emissions.1Whilecurrently this figure is less than the 28% of globalcarbon emissions attributed to building energyuse, it is estimated that, due to the rapid growth ofnew construction needed to meet the demand ofgrowing populations, nearly half of the total carbonemissions from new construction from now until 2050will be attributable to the embodied carbon of ourbuilt environment.2 proportion of embodied carbon they could reduce.The strategies were then mapped against differenttypes of building-sector policies. For the first task, Arup quantified the reductionpotential of various strategies through 2045,which is the net zero target date for the state ofCalifornia. Embodied carbon reduction strategiesin buildings were categorized as those that areimplemented at the project scale, building systemscale, or procurement (material) scale.Strategiesto optimize the project were determined to havethe most reduction potential in the short term whilestrategies to optimize procurement (i.e., material-levelreductions) had the most reduction potential in thelong term.This is because many of the technologiesto decarbonize material production are slower toscale. In contrast, strategies to optimize the projectthat focus on building less or more efficiently can beimplemented immediately. While there has been extensive focus on policiesaddressing decarbonization of industrial materials andseparately on addressing energy use in buildings, thesepolicies reduce material production emissions andoperational emissions. Additional policies are neededto reduce the balance of whole building emissionsaffected by design and construction practices. Thegoal of this study was to fully synthesize the broadertechnology and policy landscape relevant to embodiedcarbon in buildings. Based on evaluating both ease of implementationand magnitude of reduction potential, policies takingboth a building-focused approach and material-focused approach would lead to the highest Potentialscale.Moreover, both a building-focused approachand material-focused approach can be effectivelyintegrated into building codes. A building-focusedapproach uses whole building life-cycle assessmentto evaluate performance. A material-focused approachuses environmental product declarations to evaluateperformance. While examples of building codeintegration are provided within the report,mid-cyclechanges to CALGreen are already underway. The study chose to focus on the state of California andlocal governments within the state, which allows theassessment to consider feasibility more practically andspecifically. California was chosen due to its capacity,leverage, and track record for lowering barriers andrisks for others in the nation and around the world. Surely enough, legislative movement aroundembodied carbon in California is rapidly developing.Assembly Bill (AB) 2446, signed into law in 2022,directs the development of a framework for measuringand reducing the average carbon intensity of buildingmaterials with a target set of 40% reduction by 2035.Meanwhile, the public sector in California has shownmarket leadership in low carbon material procurementthrough the landmark bill AB 262, known as the BuyClean California Act. Most recently, the CaliforniaBuilding Standards Commission voted unanimouslyto adopt embodied carbon requirements into the state’sgreen building code, known as CALGreen. In addition to statewide code update efforts,localbuilding code authorities can adopt more stringentrequirements, and local planning authorities can domore to integrate embodied carbon into planningrequirements and zoning incentives. Addressingembodied carbon in city climate action plansand supporting industry-led initiatives to educatepractitionerson the importance of, and methods toreduce, embodied carbon are additional levers that canhelp cut embodied carbon. A wide range of strategies can be deployed to reduceembodied carbon in the built environment, encouragedby policy action. This study looked first at differenttypes of available strategies and estimated the relative The report herein provides a policy roadmap anddescribes how the research team arrived at thesespecific recommendations. Embodied carbon reduction roadmap 1Embodied carbon reduction roadmap project, building system, or procurement (material)level. The cumulative global warming potential(GWP) reduction over time for each strategy categorycan then be estimated over time. This report considersa timeline through 2045, which is the target for thestate of California to become net zero as establishedby Executive Order (EO) B-55-18, and through 2035,the target set in AB 2446. Aru