Concrete is the foundation of modern infrastructure—roads, bridges and buildings rely on it. However, its key ingredient, cement, is responsible for approximately 8 percent of global CO2 emissions. The good news? A combination of time-tested solutions, and emerging innovations in low-carbon concrete are reducing emissions while maintaining performance. And the future of their success in the marketplace just may well be decided at the local level. 

The carbon problem with concrete

Cement, specifically Portland cement, is at the core of concrete’s carbon footprint. Producing it requires heating limestone (calcium carbonate) at high temperatures, releasing CO2 both from fossil fuel combustion and chemical reactions. With growing urbanization, reducing these emissions is critical.

Solutions: A mix of proven and emerging innovations

No single solution exists, but a combination of efficient material use, alternative cementitious materials and carbon sequestration in concrete is making an impact.

More efficient material use: Many projects overuse cement. Optimizing mix designs can reduce emissions without sacrificing strength or safety.

Supplementary Cementitious Materials (SCMs): Replacing Portland cement with fly ash, slag, calcined clay or ground glass pozzolan (GGP) lowers emissions. New York-based Pozzotive and Klaw Industries produce GGP from recycled glass, enhancing durability while cutting carbon footprints.

Recycled and upcycled materials: Concrete waste makes up a significant portion of demolition debris. Repurposing crushed concrete reduces demand for virgin materials. Some innovations even leverage concrete’s alkaline chemistry to absorb and mineralize CO2. Kingston Block, a New York manufacturer, uses recycled materials in masonry units, lowering embodied carbon.

Carbon sequestration in concrete: Technologies are incorporating captured CO2 into concrete, permanently storing it while improving performance. Carbon to Stone, a New York company, mineralizes captured CO2 within concrete. Carbon curing injects CO2 during curing, reducing cement needs while strengthening the material. Additionally, biochar, a stable carbon form from biomass, can act as a cement substitute or aggregate, further cutting emissions.

Alternative cements: Emerging cements, such as those from Sublime Systems, eliminate the need for high-temperature kilns, significantly reducing emissions. As Portland cement contributes 90 percent of concrete’s emissions, these innovations are crucial.

How local governments can promote low-carbon concrete

Municipalities play a vital role in adoption through public procurement policies and updated building codes.

Public procurement policies: Cities, counties and states purchase massive amounts of concrete. By prioritizing low-carbon options, they create demand and provide market certainty for new products. New York State’s Buy Clean executive order is a leading example.

Building code updates: Localities can set embodied carbon limits for materials. The American Concrete Institute (ACI) recently introduced a low-carbon concrete code, which local governments can adopt to drive emissions reductions in private construction.

Financial tools to support adoption: A major hurdle for some very promising forms of low-carbon concrete is higher costs, relating to the fact that new products almost always start more expensive in the early days, before scaling drives costs down. One way to level this differential in the short term is through financing, and specifically Commercial Property Assessed Clean Energy (C-PACE) financing, which allows developers to fund low-carbon materials through long-term loans repaid via property taxes. New York State has C-PACE in place, with 75 municipalities through the state opted in. Integrating low-carbon concrete as an eligible project type of C-PACE, will make new materials more financially viable.

New York State’s leadership

New York is at the forefront of sustainable construction policies. The Buy Clean New York order mandates lower-carbon materials in state-funded projects. NYSERDA’s Roadmap to Carbon Neutral Buildings provides pathways to cut built-environment emissions, supporting research and incentives for low-carbon concrete.

Local governments have been pivotal, too. Since concrete is produced and used locally, municipalities have significant influence. And as a home rule state, New York enables localities to set building and procurement policies that accelerate the shift toward low-carbon materials.

Transitioning to low-carbon concrete is both an environmental necessity and an economic opportunity. By reducing emissions in one of the world’s most-used materials, we can make meaningful climate progress while ensuring durability and safety. With innovation, policy support and market demand, concrete’s future can be strong and sustainable.

Chris Neidl is a policy advocate, researcher and organizer focused on accelerating the adoption of low-carbon concrete and sustainable construction practices. He is the co-author of NRDC’s “Design Guide to State and Local Low-Carbon Concrete Procurement.” A native of Albany, NY, and a long-time Brooklyn resident, he is currently based in Austin, TX.