In a recently published study, researchers from the Chinese Academy of Sciences have unveiled new advancements in China’s cement industry’s carbon capture capabilities and its potential contributions to carbon neutrality.

Cement production is a significant source of human-induced carbon emissions. As the world’s leading cement producer, China accounts for more than half of the global cement output annually. The industry’s carbon emissions are estimated to be around 7% of the country’s total emissions. Yet, the alkaline compounds in cement materials can slowly absorb carbon dioxide (CO₂) from the surrounding environment through mineral carbonation, serving as a potential carbon sink.

The researchers, from the Chinese Academy of Sciences' Institute of Applied Ecology, conducted a comprehensive carbon sink accounting for China’s cement. "Carbon sink accounting" is a method used to measure and track the amount CO₂ that is absorbed from the atmosphere by natural or artificial reservoirs, known as carbon sinks. These sinks can include forests, oceans, and even certain industrial materials like cement, which can capture and store CO₂ over time. The study found that from 1930 to 2021, China’s cement carbon sink has been growing steadily. By 2021, it reached 426.77 Mt CO₂ per year, which is equivalent to 2.51-4.54% of the global terrestrial carbon sink. During this period, the cumulative carbon absorption by cement was approximately 7.06 Gt CO₂ , offsetting 50.7% of the cement industry’s emissions (13.91 Gt CO₂) during the same timeframe.

The IPCC Guidelines for National Greenhouse Gas Inventories provide an approach for quantifying CO₂ emissions during cement production, but ignore the carbon absorption by cement materials. The authors of the new study suggest that China should play a more leading role in developing methodologies for cement carbon accounting. They also call for enhanced international cooperation in the field of climate change to gain global recognition for China’s cement carbon capture calculations.

The authors believe that the cement industry has the potential to achieve net-zero emissions. They recommend that the industry can contribute to carbon neutrality goals through both technological and policy measures. Technologically, the large-scale application of energy-saving and green production technologies, along with the promotion of breakthrough carbon capture and storage (CCS) technologies, are suggested. On the policy front,  several measures are recommended to encourage more carbon-neutral practices in the cement industry. For example, increased support for research and development would help companies develop new technologies. In addition, a ranking system based on companies’ carbon emissions and absorption capabilities would incentivize the progress.

This study has been published in the bilingual journal Science China Earth Sciences.