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CLF WBLCA Benchmark Study v2

The Carbon Leadership Forum is currently conducting a multi-year project to develop a robust and harmonized database of WBLCA benchmarks.  The first CLF Benchmarking Study (v2) report is now available. Please visit the California Carbon Report webpage for more details!


In 2017, the CLF published the Embodied Carbon Benchmark Study for North American buildings. Since then, the practice of whole-building life cycle assessment (WBLCA) has grown rapidly in the AEC industry, and it has become clear that more robust and reliable benchmarks are critical for advancing work in this field. The new CLF WBLCA Benchmark Study (Version 2) will build upon research and insights from the 2017 study. The project will expand our research methodology and result in geographically and typologically specific benchmarks for buildings, systems, and assemblies modeled with consistent scope and background data. This will allow designers and decision-makers to set reliable embodied carbon targets and understand the potential for reduction throughout the design and construction processes.

Problem Statement

Currently, it is difficult to set robust targets or benchmarks for the embodied carbon of building projects due to the lack of a robust collection of WBLCA models. Existing studies have been based on a very small number of calibrated models, or large low-quality and non-harmonized datasets, making it difficult to understand whether variability in carbon emissions stems from modeling practice, background LCI data, or actual design decisions. Over the last 5 years, there has been rapid adoption of WBLCA by architecture and engineering firms during design and construction. However, there is currently no centralized repository of WBLCA models from which to conduct research or evaluate trends.

This project will fill a critical gap in the AEC industry and help enable architects, engineers, policy makers, and the entire design community to work towards realistic and measurable embodied carbon reductions at the building scale.

Project Components

There are 3 components to this project that build on each other to ultimately deliver a more robust dataset, analysis framework, and set of benchmarks:

  1. Pilot Phase (Fall/Winter 2022) The pilot phase set forth the development and testing of data collection processes and data analysis methods to support future work throughout the study. This phase involved conducting background research, hosting industry workshops, establishing pilot partners, and collecting pilot dataset of projects to inform the feasibility and infrastructure for future work.
  2. California Carbon Report (Spring 2024) This project component focused on the whole-life carbon impacts of a discrete set of buildings in California and examined the relationship between embodied and operational carbon impacts over time when considering future grid decarbonization projections. It culminated in the California Carbon Report: An Analysis of the Embodied and Operational Carbon Impacts of 30 Buildings, which can be downloaded on the California Carbon Report webpage.
  3. North American Benchmarks and Database (2023-2024+) From Summer 2023 to Spring 2024, the CLF collected a dataset of 200+ high-quality WBLCA models of real-world building projects with the help of over 30 firms located in North America. Now, the team is focused on cleaning and harmonizing the results for subsequent analysis. Moving forward, this dataset will be used to conduct statistical analysis on the embodied carbon impacts of buildings and improve current estimates of typical, low, and high values for buildings in North America. Anticipated outcomes of this study include WBLCA modeling and reporting guidance, findings from our background research and literature reviews, exploratory data analysis and preliminary baseline figures, a data visualization dashboard, open-access data for the buildings collected, and other publications.

    Project Documentation

    The following documents were developed to support data collection for the CLF WBLCA Benchmarking Study (v2). They can be downloaded below.

    Data Collection Status

    We are no longer actively collecting data for this study. However, we intend to expand on this research and collect more building project data in the future. If you are interested in contributing project data for future research, please fill out our Expression of Interest form. Responses from the form are confidential and will be used internally by the CLF to help inform the scope and structure of the project.

    For other general inquiries about the project please email [email protected].

    Project Updates

    Publication of The California Carbon Report – May 13, 2024

    The first report from the CLF WBLCA Benchmark Study (v2) is now available! In this study, we investigated the use of whole life carbon assessment (WLCA) through a sample of 30 new construction building projects located in the State of California that were sourced from design practitioners as part of the CLF WBLCA Benchmark Study (v2). Please visit the California Carbon Report webpage to download the full report. 

    Greenbuild 2023 Update – September 28th, 2023

    We recently had the pleasure of presenting a project update alongside Lindsey Kahler of SERA Architects and Brie McCarthy of Miller Hull at this year’s Greenbuild 2023. Our session was titled Embodied Carbon Benchmarking: the prerequisite to making meaningful impact reductions within the AEC industry, and we explored the importance of embodied carbon benchmarking and the ways in which design practitioners are engaging in similar efforts at the firm-scale. As promised to our Greenbuild audience, our slides can be downloaded here.

    Open Call for Data Contributors—May 22nd, 2023

    We are excited to announce the official launch of our open call for data contributors! Our goal is to collect at least 200 WBLCAs of real-world projects so that we can analyze the environmental impacts of buildings and provide critically needed benchmark data to designers, policymakers, and other organizations working to reduce embodied carbon. To do this will require the help of our amazing CLF network and other practitioners out in the real world conducting WBLCAs. With enough data contributors, we may be able to far exceed our goal of collecting 200 projects and build an even more robust dataset.

    Data Collection Introduction call—May 3rd, 2023

    We recently completed an informational call on the data collection methods and processes that will be used for the WBLCA Benchmark Study v2. This recording introduces the types of data that we will be seeking as well as what the process will look like for participants who are interested in contributing data to this study. It includes examples of project requirements, modeling requirements, data fields that will be collected, and brief overviews of guidance documents that will be provided. We will soon be launching surveys for practitioners to express their interest in contributing data and indicate the types and quantities of projects that may be available. Additionally, the survey will include opportunities for a wide range of practitioners to provide feedback on current WBLCA modeling practices that will help to further inform our data collection efforts.

    We are gearing up to officially launch our call for data soon. Please stay tuned for more updates!

    Official Launch of Phases 2-3 – March 27th, 2023

    The CLF is pleased to announce the launch of the next two phases of the CLF Benchmark Study V2. This year we will be developing the “California Total Carbon Report” (phase 2) which will focus on the whole-life carbon impacts of buildings in California, including both operational and embodied carbon emissions. Concurrently, the CLF will be gathering data and conducting stakeholder engagement to support our larger “North American Benchmark and Public Database” (phase 3) which will continue through 2024 and lead to updated embodied carbon benchmarks for North America.

    We’ve recorded a full project overview that describes the entire project and each individual effort in more detail. This 15-minute recording also outlines the ways we will be conducting stakeholder engagement in the coming weeks and future project efforts to be aware of.

    Pilot Phase Completion – October 2022

    The project team has recently wrapped up our initial pilot phase of the WBLCA Benchmark Study which focused on reviewing existing literature and building internal data infrastructure. During the pilot phase, we:

    • Developed a process for architecture or engineering firms to easily submit detailed Tally models, Bill of Materials, and other project information.
    • Developed infrastructure to enable robust data analysis at a building, assembly, and material scale.
    • Conducted extensive background research on WBLCA benchmarking and benchmark development in the US and Europe.
    • Tested data collection templates and reporting processes.
    • Identified stakeholders and interested parties for future participation.

    In the next phases of the project we will expand the project to:

    • Include a larger sample set of firms, projects, and WBLCA tools.
    • Build upon the work completed in the Pilot Phase.
    • Establish stakeholder working groups for technical advisory, communications, harmonization, and more.


    The research team would like to thank the Alfred P. Sloan Foundation, the ClimateWorks Foundation, and the Breakthrough Energy Foundation for supporting this research project.

    CLF WBLCA Benchmark Project Logo

    The California Carbon Report

    An Analysis of the Embodied and Operational Carbon Impacts of 30 Buildings


    Read Report

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