Evaluation and mitigation of cement CO₂ emissions: projection of emission scenarios toward 2030 in China and proposal of the roadmap to a low-carbon world by 2050

Much attention is being paid toward reducing the carbon dioxide (CO₂) emissions associated with China’s cement production. However, as part of China’s international commitment to reduce carbon intensity, the inter-annual changes and driving forces behind CO₂ emissions must be determined for the 2001–2015 period, along with the projection of the cement-related CO₂ emissions until 2030. The objective of this article is to analyze the CO₂ emission factors (EFs) and CO₂ emissions from 2001 to 2015, project CO₂ emission scenarios of China’s cement industry until 2030, and propose a low-carbon roadmap for the global cement industry by 2050 based on a series of practical reduction measurements performed by China. The results of our study indicate that CO₂ EFs in 2015 were 55.36% lower than those in 2001, but CO₂ emissions were 72.90% higher than those in 2001. The main reason for the decreasing total active CO₂ EFs are policies enacted by the Chinese government regarding the removal of excess capacity and elimination of backward capacity as well as the technological innovation and ongoing annual reductions in the clinker-to-cement ratio (C/CR). Meanwhile, the driving force behind the increased cement-related CO₂ emissions was the substantial growth in cement output. Scenarios regarding CO₂ emissions by 2030 show an uncertainty regarding CO₂ emissions, ranging between 3.51 and 11.70%, and CO₂ EFs are expected to be 59–69% lower than those in 2005. CO₂ emissions from the global cement industry from 2020 to 2050 based on CO₂ capture, utilization, and storage (CCUS); utilization of alternative raw materials (ARMs) and alternative fossil fuels (AFFs); and technological innovation account for 39.3, 29.3, 24.7, and 6.7% of the CO₂ reduction capability, respectively. It is possible to reduce ~ 1524 Mt of CO₂, and the global optimal emissions by 2050 are ~ 2082 Mt of CO₂.