How States and Cities Are Tackling Embodied Carbon: A Look at 'Buy Clean' and Building Code Policies

State and local governments are implementing policies to reduce embodied carbon in construction, focusing on two main strategies: 'Buy Clean' procurement standards and building code amendments. These approaches leverage public purchasing power and direct regulation, respectively, to drive the use of lower-carbon materials like concrete.

Rick Donovan

October 8, 2026 · 5 min read

State and local governments are increasingly targeting the hidden climate impact of construction through policies aimed at reducing "embodied carbon"—the greenhouse gas emissions associated with manufacturing, transporting, and installing building materials. These emissions occur before a building is even occupied but constitute a significant portion of its total lifetime carbon footprint. To address this, policymakers are primarily adopting two distinct strategies: procurement standards, often known as "Buy Clean" policies, and direct amendments to building codes. While both aim to promote the use of low-carbon materials, they operate through different mechanisms and affect different sets of construction projects. Understanding these approaches is crucial for construction professionals and public officials navigating the evolving landscape of sustainable building.

Comparing Embodied Carbon Policy Mechanisms

The two main strategies for regulating embodied carbon in construction—procurement standards and building code amendments—differ significantly in their scope, mechanism, and application. Procurement policies leverage a government's purchasing power to create a market for low-carbon materials, primarily affecting public projects. In contrast, building codes set mandatory requirements for a much broader range of private and public construction projects within a jurisdiction. According to RMI, cities are leveraging these and other strategies to meet their climate commitments by integrating embodied carbon reduction goals into their overall policy frameworks. The fundamental distinction lies in whether the policy uses market incentives driven by public spending or direct regulatory mandates for the entire construction sector.

A Comparison of 'Buy Clean' Procurement and Building Code Policies
Feature	'Buy Clean' Procurement Standards	Building Code Amendments
Policy Type	Procurement policies that integrate low-carbon requirements into government purchasing for public projects.	Direct regulatory changes to building codes that set limits on embodied carbon for construction within a jurisdiction.
Mechanism	Uses the government's role as a major purchaser to create demand for materials with lower greenhouse gas emissions.	Establishes mandatory, enforceable limits on the embodied carbon of materials or entire buildings.
Primary Target	Materials purchased for publicly funded construction projects, such as infrastructure and government buildings.	All new construction and major renovation projects that fall under the jurisdiction of the building code, including private developments.
Example Implementation	A state requiring material suppliers for a public project to meet specific greenhouse gas reduction benchmarks.	The City of Portland's requirement setting maximum Global Warming Potential (GWP) values for specific concrete mixes used in city-solicited projects.

Case Study: Portland's Concrete Embodied Carbon Thresholds

The City of Portland, Oregon, provides a clear example of how a municipality can implement embodied carbon regulations through a multi-faceted approach. The city's "Concrete Embodied Carbon Threshold Requirements" establish a maximum global warming potential (GWP) for various types of concrete used in construction projects that are either owned or solicited by the city. This policy directly targets one of the most carbon-intensive materials in the built environment. By setting specific GWP limits, Portland ensures that contractors select lower-carbon concrete mixes for public works, effectively using its procurement power to drive down emissions.

In addition to material-specific limits, Portland is also tackling embodied carbon from a design and planning perspective. The city's "Parking Compliance Amendments Project" eliminated minimum parking requirements citywide. This zoning change is intended to reduce the overall amount of concrete used in new developments, which the city anticipates will cause a "tremendous reduction in embodied carbon." This illustrates a sophisticated strategy that goes beyond simply swapping one material for another; it aims to reduce the total volume of high-impact materials needed in the first place. This dual approach—setting procurement standards for city projects while also amending citywide rules to encourage less material-intensive design—shows how different policy tools can be combined for greater impact.