Global and National CO₂ Uptake by Cement Carbonation from 1928 to 2024

Abstract. The hydration products of cement materials can absorb atmospheric CO₂, and this carbonation process provides an important decarbonization pathway for the cement industry. Global carbon sequestration by cement materials has been reported, but carbon uptake in different countries remains unquantified. Here, we quantify the national cement carbon uptake from 1928 to 2023 based on 58517 activity level data from 163 cement-producing countries and regions worldwide and 6186 carbonation parameters from detailed data records of 42 countries, and project their trend to 2024. The global CO₂ uptake by cement materials increases from 7.74 Mt yr^-1 (95 % confidence interval, CI: 5.84–9.85 Mt CO₂ yr^-1) in 1928 to 0.84 Gt yr^-1 (95 % CI: 0.71–1.00 Gt yr^-1) in 2023, and projected to rise to 0.86 Gt yr^-1 (95 % CI: 0.73–1.02 CO₂ yr^-1) in 2024. The accumulated CO₂ uptake from 1928 to 2023 is 21.26 Gt CO₂ (95 % CI: 17.93–25.17 Gt CO₂), which offsets about 46 % of the cement process emission (46.06 Gt CO₂) in past 96 years. Simultaneously, the dominance in cement carbon uptake has shifted from the USA, Japan and some European countries to emerging economies such as China and India, which account for 38.0 % and 9.1 % of total CO₂ uptake, respectively, in the last decade (2014–2023). By analyzing the long time-series carbon emission and uptake of the 42 countries with detailed data, we find they contributed 82.1 % of global cement CO₂ uptake from 1928 to 2023, including 21 peaked countries and 21 non-peaked countries in cement emissions The annual carbon offset level (the ratio of uptake to process emission in a given year) shows a remarkable decrease due to the temporal lag of cement carbon uptake. This is significant for countries with higher cement imports, for example, the cement industry in Australia and Japan have achieved net-zero when considering the cement carbonation sink. This study provides a precise bottom-up quantification to cement carbonation sinks at national and global levels. All the data described in this study are accessible at https://doi.org/10.5281/zenodo.13827861 (Wu et al., 2024).