California has become the first U.S. state to establish general code standards mandating the reduction of embodied carbon emissions in large commercial and school buildings. The decision, recently announced by the California Building Standards Commission, encompasses commercial buildings exceeding 100,000 square feet and school projects over 50,000 square feet. The regulations will take effect on July 1, 2024.

Embodied carbon represents the greenhouse gas emissions associated with building materials throughout their life cycle. This includes not only the manufacturing and transportation of these materials but also their installation, maintenance, and eventual disposal.

The recent updates were integrated into the 2022 California Green Building Standards Code. They provide three distinct compliance avenues for design experts: Reusing at least 45% of an existing structure; Using materials that adhere to specified emission limits; A performance-based approach employing a Whole Building Lifecycle Assessment analysis.

“It can take up to 80 years to overcome embodied carbon’s impact through strategies that reduce energy usage or operational carbon; the planet doesn’t have that time,” said AIA California President Scott Gaudineer in a statement. “Today’s actions by the Division of the State Architect, led by California State Architect Ida Clair, AIA, and the California Building Standards Commission led, until very recently by Executive Director Mia Marvelli, AIA, codify a cultural shift: To meet decarbonization timelines set by California law, embodied carbon must be reduced in addition to operational carbon.”

News of the change comes one month after it was revealed that California was amending its building codes to facilitate adaptive reuse. Last year, meanwhile, California’s building codes were updated to allow for high-rise mass timber buildings.