CO₂ emission reduction potential in China from combined effects of structural adjustment of economy and efficiency improvement

China has committed to decreasing its emission intensity by 60% to 65% by 2030 compared to 2005 levels and achieving carbon neutrality by 2060. It is of great importance to evaluate the CO2 emission reduction potential to quantify the amount of CO2 emissions that can be less generated and the amount that should be balanced out. Economic structure adjustment and CO2 emission efficiency improvement will contribute to mitigating CO2 emissions, which always happen simultaneously in the real world. However, few studies consider these issues simultaneously, which can lead to inaccurate estimation. A scenario analysis framework is proposed to estimate their combined effects, and an indicator is proposed to measure the technical feasibility of achieving the reduction potential. A set of scenarios are designed based on this framework and we find that: (1) to achieve carbon neutrality, 6161.16 Mt of CO2 emissions of China can be less generated compared to 2017 levels by significantly increasing its tertiary industry share to high-income entities’ level and adopting the most advanced technology to improve emission efficiency; the remaining 2732.40 Mt of CO2 emissions should be removed by carbon offsetting. Regarding emission intensity, 81.39% can be reduced compared with the 2005 level; and (2) Technical feasibility analysis shows Sichuan, Chongqing, and Anhui have the largest technical barriers in achieving the reduction potential. The proposed scenario analysis framework can provide a reference not only for China to achieve the emission mitigation pledges, but for countries with significant technological differences and structure adjustment to formulate mitigation strategies.