The History of the Carbon Leadership Forum

LEED and the US Green Building Council

It’s fair to date the inception of the modern US green building movement to April 1993 with the first meeting of the US Green Building Council and the first glimmer of the LEED standard for buildings. In those early days, people talked about “sustainable materials,” but had no easy way to describe what such a material was, or the critical role played by embodied carbon, and data was not available to compare or select low-carbon materials. In consequence, the focus of LEED and USGBC for a quarter century was reducing operational carbon—or carbon emissions associated with the energy use of construction and buildings. In recent years, LEED has begun to include an emphasis on reducing embodied carbon of materials.

Architecture 2030 Issues the 2030 Challenge

In 2005, Ed Mazria and Architecture 2030 issued the 2030 Challenge. The initiative comprised incremental carbon reduction goals over a 25-year timeline that were consistent with those called for by the global scientific community at the time. Meeting the targets would mean that all new buildings and major renovations would be zero carbon by 2030. The Challenge has since been adopted by architectural design firms, states, cities, counties, the American Institute of Architects (AIA), International Union of Architects, US Conference of Mayors, and the China Accord.

International Living Future Institute and the Living Building Challenge

The Living Building Challenge, an international sustainable building certification program, was created in 2006 by the non-profit International Living Future Institute (ILFI). The end goal of the Challenge was to encourage the creation of a regenerative built environment at all scales, from buildings—both in new constructions and renovations—to infrastructure, landscapes, neighborhoods, both urban and rural communities, including all aspects of performance such as energy, place, water, health and happiness, equity, and beauty. In recent years, the Challenge has evolved to include the reduction of embodied carbon.

Founding of the Carbon Leadership Forum

A group of self-described “carbon nerds” gathered on September 10th, 2009 in an office on Market Street in San Francisco. Meeting attendees recognized that buildings and infrastructure, and the materials used to construct them, have a sizable carbon footprint—otherwise known as embodied carbon. The meeting’s purpose was to inaugurate a new initiative called the “Carbon Leadership Forum (CLF),” describing CLF’s mission as: “To drive carbon footprint standards for the built environment.” They discussed the urgency of the problem, the need for carbon accounting to drive change, and the project of setting new carbon standards for the building industry. They asked a big question: What would it take to enable and accelerate collective action to decarbonize built environments?

2030 Challenge for Products; CLF Hosted by the UW

On February 14, 2011, Architecture 2030 issued the 2030 Challenge for Products, a plan to dramatically reduce greenhouse gas (GHG) emissions resulting from the manufacturing and transportation of building products. On the same day, Kate Simonen, founding executive director of the new CLF and then an assistant professor of architecture and engineering at the University of Washington, announced that the CLF would have a home at the University’s College of Built Environments, and would work to help the building industry meet the 2030 Challenge for Products. “Without good data, clear standards and industry collaboration, we will not be able to accurately predict and reduce the carbon impact of building materials and products,” said Kate Simonen. “The 2030 Challenge for Products provides critical leadership to motivate development of low-carbon industries and rigorous environmental performance standards. Ambitious targets for carbon reduction cannot be met by increasing energy efficiency alone.”

Concrete PCR for North America

In 2012, the CLF developed and published version 1.0 of a North American Product Category Rule (PCR) for concrete, the most widely-used building material in the world. PCRs are sets of rules and requirements that guide measuring and reporting a specific product’s life cycle impact when conducting an Environmental Product Declaration (EPD).The PCR was initiated in May of 2011 by the CLF in response to a request by CLF sponsors. The first draft for stakeholder comments was published on Feb 14, 2012 and was open for a review period of 45 days. Over 200 comments were received and integrated into a revised version. A second version of the PCR was posted for public comment on August 15, 2012 and was open for a review period of 20 days. 370 comments were received and integrated into this revised version.

First publication of a Concrete EPD

The CLF’s concrete PCR published in 2012 laid the basis for the first publication of an Environmental Product Declaration (EPD) by ready-mix concrete supplier Central Concrete, a sponsor of the CLF, in April 2013. Often compared to a nutrition label, EPDs provide the facts and transparency needed to make informed decisions as they relate to such characteristics as global warming potential, ozone depletion and water use. Central Concrete was also the first U.S. company, in any industry, to produce EPDs at the individual product level. This is in contrast to EPDs that are developed for classes of products, an approach that diminishes the value of the EPD because specific product performance characteristics are only matched to general environmental impacts within a category.

Publication of Kate Simonen’s Life Cycle Assessment

A handbook for architects and building industry professionals, Life Cycle Assessment by CLF founding executive director Kate Simonen was published by Routledge and released April 11th, 2014.  The handbook included technical information and explanation of life cycle assessment methodology, data, and applications for building practice, and addressed the dynamic and dialectic of building and ecology, presenting the key theories and techniques surrounding the use of life cycle assessment data and methods. Although a simple CLF web page had existed before 2014, the organization published its first complete web site that year. You can visit the original 2014 CLF website, now preserved in the Internet Archive.

Low Carbon Building Summit

In September of 2015, the Carbon Leadership Forum organized and hosted the Low Carbon Building Summit at the University of Washington, bringing together leaders from across the North American building industry for a two-day program focused on life cycle assessment (LCA) concepts, methods, results, and resources, use of Environmental Product Declarations (EPDs to drive development of low carbon materials, and LCA case studies of buildings to identify options for carbon reduction. The following month, October 2015 CLF partnered with the US Green Building Council and CERES, a network of influential investors and companies integrating environmental, social, and governance practices into core business strategies, to issue the Building and Real Estate Climate Declaration, (preserved in the Internet Archive) calling on the building and real estate sector to direct action to realize the opportunity of a low carbon economy.

Embodied Carbon Benchmark Study

The Carbon Leadership forum published its landmark Embodied Carbon Benchmark Study as the first stage of the LCA for Low Carbon Construction project funded by The Charles Pankow Foundation, Skanska USA and Oregon Department of Environmental Quality. The Study compiled over 1,000 LCA building-level studies in an interactive database, the first attempt in North America to provide a quantitative starting point to drive low-carbon construction. Early 2017 also saw the launch of CLFs first online community, the Embodied Carbon Network (ECN), with over 200 members in its first year. The ECN was renamed two years later to the CLF Community. In May of 2017, CLF launched a newly redesigned website, now preserved in the Internet Archive, using the signature purple color of the CLF’s host, the University of Washington.

Carbon Smart Building Day; LCA Practice Guide; SE 2050 Challenge

The Carbon Leadership Forum hosted Carbon Smart Building Day, a day-long conference with over 300 attendees representing over 200 companies in San Francisco on September 11, 2018, affiliated with the Global Climate Action Summit. The Day aimed to accelerate a global movement to decarbonize the built environment, including both operational and embodied carbon, sharing the latest tools, resources and programs, and to make all new buildings healthy, equitable and just. Over 100 companies signed the Carbon Smart Building Declaration, calling for reeduction of both embodied and operational carbon along with creating healthy buildings for healthy communities. The Day concluded with the bullhorn-supported reading of the Declaration by Andrew Himes with Kate Simonen. Also in 2018, the CLF published Life Cycle Assessment of Buildings: A Practice Guide, a step-by-step LCA primer and technical guidance document. The Practice Guide introduces the use of LCA to analyze the environmental impacts of buildings in order to help building professionals apply LCA in practice. The SE 2050 Challenge aimed to inspire structural engineers to measure progress made toward a zero carbon building sector vision for 2050. In response, the Structural Engineering Institute adopted the SE 2050 Commitment, obligating signatory structural engineering firms to meet embodied carbon benchmarks and targets, and challenging structural engineers to collect quantifiable structural material data from building projects.

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Buy Clean; EC3 Tool; Material Baselines; NGO/Government Roundtable

In February, 2019, the CLF published the Buy Clean Washington Study, an innovative and comprehensive analysis of proposed legislation in Washington State to mandate the procurement of low embodied carbon materials in building and infrastructure projects funded by public funds. At Greenbuild in November, 2019, the Carbon Leadership Forum released the Embodied Carbon in Construction Calculator (EC3) tool, a free, cloud-based, easy to use tool that allows benchmarking, assessment and reductions in embodied carbon, focused on the upfront supply chain emissions of construction materials, based on a robust database of digital, third-party verified Environmental Product Declarations (EPDs), allowing the building industry to make carbon smart choices during material specifications and procurement.  Skanska USA and C Change Labs conceived of the solution, and the CLF incubated the project to accelerate its development. The CLF provided the first version of the Material Baselines used by the EC3 tool to compare product EPDs and enable practitioners to make low-carbon decisions (and continues to publish updated versions). After Greenbuild, a new nonprofit, Building Transparency, was formed to continue EC3 development. In September, CLF invited 12 other leading nonprofits to form the NGO/Government Roundtable on Embodied Carbon, to share news, strategic plans, resources, and tools; report on conferences, webinars, and meetings; inspire and facilitate ongoing communication; and encourage convergence on shared terminology, data standards, benchmarks, and targets.

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Wood Carbon Seminars; Regional Hubs

The Wood Carbon Seminars was a webinar series hosted by the Carbon Leadership Forum in the Spring of 2020, bringing together wood experts to answer common and critical questions about the carbon impacts of wood from the building industry. The webinars were organized around four main categories: 1) Background and Basics, 2) LCA and Wood, 3) Tracking Biogenic Carbon in North America, and 4) Wood and the Building Industry. Leading up to the release of the EC3 tool in November 2019, many wood experts had pointed out issues with how we were presenting wood LCA data in the tool. Sustainability-oriented AEC professionals were interested in using wood for its environmental benefits, but also wary of the negative consequences of logging and didn’t want to drive deforestation. In the fall of 2019, CLF member Anthony Pak in Vancouver, BC posed an inspired question: What if CLF members in Vancouver, and then in cities around the world, could connect in local networks to share best practices, discuss solutions, and spread the word about how we can decarbonize the built environment? The idea spread rapidly, and by the end of 2020 CLF Regional Hubs had been launched in a dozen cities with another dozen being formed.

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Policy Toolkit; Owner’s Toolkit; Leadership Summit for Wood, Climate, and Forests; Carbon-storing Materials

In February, 2021, CLF launched the Embodied Carbon Policy Toolkit, including an array of resources to support the crafting of policies to radically reduce embodied carbon, education about Buy Clean, guidance on carbon disclosure, steps to develop and guidance to implement Buy Clean policy, CLF’s new policy map displayed a handful of existing public policies aimed at reducing embodied carbon emissions in materials and construction. (Since then, embodied carbon policies have exploded in number, both in North American and across the globe.) Also in February, CLF published a seminal research paper on Carbon-Storing Materials, with a focus on biogenic materials. In April, CLF published the Embodied Carbon Toolkit for Building Owners, including overview of the opportunity for investors, developers, building owners and tenants to radically reduce embodied carbon and an array of resources to support action with company-wide policies and practices. Also in April, CLF hosted the Leadership Summit for Wood, Climate, and Forests. In July, CLF published 2021 Material Baselines. Finally, in November CLF partnered with the American Institute of Architects (AIA) to publish the AIA-CLF Embodied Carbon Toolkit for Architects.

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POD/LCA; Whole Building LCA Benchmark Study; MEP 2040 Challenge; Policy Education

In the fall of 2021, CLF had issued the MEP 2040 Challenge at the initiative of a group of CLF partners who were building system engineers. In March of 2022, the new steering committee of the MEP 2040 Commitment hosted the first of many Quarterly Forums supporting the decarbonization of MEP systems. In July, the CLF was awarded a four-year, $4M grant to support development of data, methods and tools to assess and optimize the carbon storing potential of novel materials and building systems (POD|LCA). In October, CLF’s research team completed the pilot stage of version 2 of the Whole Building LCA Benchmark Study integrating over 100 full building models (materials and LCA impacts) into a research database. Policy staff provided technical support to policy makers throughout the year, including on the use of IRA funding, informed Buy Clean policies in five states, and evaluated transportation infrastructure embodied carbon. In October, three programs initiated by the CLF (MEP 2040, SE 2050 & CLF Hubs) were highlighted in a White House Fact Sheet as examples of industry decarbonization action. In June, CLF published an Embodied Carbon Policy Educational Series that includes prerecorded videos and curriculum for in-person local discussions.

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Material Baselines; WBLCA Benchmarks; Policy Education; Infrastructure Research; ECHO

On February 3, the CLF released a new report highlighting ten case studies of policies driving lower carbon construction across the Pacific Coast. In March, CLF officially launched Phases 2 and 3 of the Whole Building LCA Benchmark Study: a) development of the “California Total Carbon Report” focused on the whole-life carbon impacts of buildings in California, and b) gathering data and conducting stakeholder engagement to support the larger “North American Benchmark and Public Database.” CLF’s first infrastructure research study was published in April. The 2023 CLF North American Material Baselines Report went public in August. Throughout the year, CLF staff participated in a number of national and international industry standards committees, and CLF policy staff provided advice and consultation on developing and implementing embodied carbon policy for the US federal government, over 20 state governments, and countless municipalities. In September, CLF announced the Embodied Carbon Harmonization and Optimization (ECHO) Project, an historic and collaborative move by a group of built environment industry groups and movement leaders to tackle the issue of rapidly reducing embodied carbon in the built environment by ensuring that all embodied carbon reporting at the whole building and whole project scale (including landscapes and infrastructure) in the US follow the same clear definitions and scopes of included impacts.

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