The climate benefits from cement carbonation are being overestimated

Rapid decarbonization of the cement industry is critical. Oversimplification of direct air capture benefits from hydrated cement carbonation has skewed decarbonization solutions. This study models global cement carbonation magnitude and its dynamic effect on cumulative radiative forcing (1930–2015). Models suggest 13.8 billion metric tons of CO₂ re-absorption; however, the slow rate reduces the climate effect by approximately 60%. Demolition emissions from crushing concrete could roughly equal carbon uptake during demolition. The sensitivity of decarbonization strategies (supplementary cementitious materials) on carbonation is investigated, highlighting the importance of emissions release and uptake timing. This work provides a reference for overcoming flawed interpretations of carbonation benefits.

Elisabeth Van Roijen, Kati Sethares, Alissa Kendall, Sabbie A. Miller