Global CO2 uptake by cement materials accounts 1930-2023.

Abstract

The majority of the carbon footprint of the cement industry originates from the decomposition of alkaline carbonates during clinker production. Recent studies have demonstrated that calcium oxides and other alkaline oxides in cement materials can sequester CO₂ through the carbonation process and partially offset the carbon emissions generated during cement production. This study employs a comprehensive analytical model to estimate the CO₂ uptake via hydrated cement carbonation, including concrete, mortar, construction waste, and cement kiln dust (CKD), covering major cement production and consumption regions worldwide from 1930 to 2023. In 2023, the global annual cement CO₂ uptake reached 0.93 Gt/yr (95% CI: 0.80-1.13Gt/yr). From 1930 to 2023, the global cumulative cement CO₂ absorption reached 23.89 Gt (95% CI: 20.47-28.74 Gt), equivalent to 52.32% of the CO₂ process emissions from cement production during the same period. Our system for estimating cement emissions and uptake is updated annually, providing consistent and accurate data for the cement industry and carbon cycle studies. This data supports improved adaptation to future challenges.