建筑部门是中国实现“双碳”国家战略的重点领域。而从宏观年度横截面视角看，建筑物化碳排放占比愈发显著，更是建筑部门落实碳减排的关键环节。但现有相关研究大都聚焦于建筑运行阶段，对中国建筑部门物化碳排放的演变规律、影响因素、减排潜力、发展趋势、排放责任等关键问题有待进一步系统深入的研究。论文按照“总量核算-因素解析-潜力分析-责任分解”的逻辑展开顺序，开展的研究工作和创新包括：（1）综合应用投入产出法与过程分析法，发展了适用于中国建筑部门年度物化碳排放的总量核算模型方法，阐明了排放总量、强度及构成演变特征；（2）协调IPAT理论框架与建筑部门投入产出特征，构建了建筑物化碳排放STIRPAT影响因素分析模型，明确了总量、直接及间接物化碳排放的影响因素及程度；（3）综合运用物质流分析法、生命周期评价理论和指数分解法，构建了中国建筑部门物化碳减排潜力综合评价模型，得到了2060年多情景组合下碳排发展趋势及减排潜力贡献；（4）基于环境拓展的多区域投入产出方法，构建了多原则下建筑部门区域碳排放责任核算模型，刻画了不同原则下部门和区域间的排放责任分解及转移关系。主要结论包括：（1）2020年建筑物化碳排放达22.8亿tCO2，占中国碳排总量的25.2%，2005-2020年贡献了中国碳排增长的38.7%，碳排强度则呈下降趋势，表明中国建筑物化碳排放增长为显著的规模驱动型；（2）间接物化排放强度和施工面积是碳排的主要影响因素，技术进步引发的能源回弹效应对直接碳减排效应有显著的抵消作用；（3）物化碳排已处于峰值平台期，多情景组合下至2060年均呈不同程度下降趋势，新建建筑面积、碳排放因子、耗材强度等是减排潜力的主要贡献因素，建筑规模补充情景亦表明既有建筑延寿减排潜力显著；（4）受需求和供给关系影响，不同原则下同一区域的建筑部门排放责任迥异，同一原则下不同区域部门碳排责任亦存在显著差异，表明在建筑部门落实“共同但有区别”责任和政策具有必要性和合理性。论文对系统推动碳排放理论方法从建筑单体到建筑部门的发展深化，对科学客观认识中国建筑部门碳排放演变规律及趋势特征等具有理论价值。所得到的影响因素、程度及责任关系等，可为从重点领域和关键环节出发制定减排目标和政策提供参考。
The building sector is key to achieving China’s carbon peaking and neutrality goals. While for the building sector, from the annual cross-sectional perspective, embodied carbon emissions (ECs) are becoming increasingly significant and play a more important role in emission reduction. However, most existing studies focus on building operational carbon emissions (CEs). There is a lack of systematic and in-depth research on the key issues of the annual ECs in China’s building sector, such as evolution law, influencing factors, emission reduction potential, development trends, and emission responsibility.This study follows the logic of “emission accounting - influencing factor deconstruction - reduction potential analysis - responsibility decomposition.” The main research works are as follows: (1) Developing a model for accounting total building ECs based on the input-output and process analysis methods and subsequently unfolding the evolution laws of total emissions, emission intensity, and composition in China’s building sector. (2) Proposing an extended STIRPAT (the Stochastic Impacts by Regression on Population, Affluence, and Technology)-based model, which aligns the general theoretical framework of IPAT (Impact = Population Affluence Technology) with the input-output features of the building sector, for deconstructing influencing factors and clarifying their impacts on the total, indirect and direct building ECs. (3) Establishing a comprehensive ECs mitigation potential assessment model based on material flow analysis, life cycle assessment theory, and index decomposition analysis and subsequently exploring ECs trends and emission reduction potential by 2060 in China’s building sector under different scenarios. (4) Developing a regional emission responsibility accounting model for the building sector under multiple principles based on the environmentally extended multi-regional input-output model and finally unveiling the emission distribution and transfer among sectors and regions from varying perspectives.The main findings are as follows. (1) The total building ECs in 2020 is as high as 2.28 billion tCO2, accounting for 25.2% of China’s total energy-related CEs. From 2005 to 2020, building ECs contributed 38.7% of China’s total CEs growth, while the ECs intensity showed a downward trend, indicating that the increase in China’s building ECs is scale-driven. (2) Building construction area and indirect EC intensity are the main factors affecting the total and indirect ECs. The energy rebound effect induced by technological progress has a significant offsetting effect on the direct carbon reduction effect. (3) Building ECs are already at the peak plateau, and the future ECs up to 2060 in all scenarios show a downward trend with varying magnitudes. The main contributors to the EC reduction potential are new building areas, emission factors, and material consumption intensity. Moreover, additional scenarios related to building scale indicate that the lifetime-extending strategy for existing buildings also has significant emission mitigation potential. (4) Due to the heterogeneity in demand and supply among regional sectors, the emission responsibilities of the building sector for the same region under various principles are incredibly different, while for various regions’ building sectors under the same principle, the disparities are also significant. This demonstrates that implementing “common but differentiated” responsibilities and policies in the building sector is of necessity and rationality.The theoretical value of this study may be summarized as systematically promoting the extension of CEs theoretical approach from individual buildings to the building sector, as well as enhancing understanding of the evolution laws and development trends of CEs in China’s building sector. From a practical perspective, the findings on influencing factors and emission responsibility may provide references for making emission reduction targets and policies aligned with the concerns of focus areas and key stages.
