The building sector is a key driver of urban economic development, yet its rapid expansion results in substantial resource and energy consumption and significant carbon emissions, challenging China's climate goals. Existing research has primarily focused on the operational stage of buildings, while paying less attention to embodied carbon emissions from building material production and urban-scale building lifecycle carbon emissions. Taking Shanghai as a case study, this study combined the material flow analysis (MFA) and life cycle assessment (LCA) to characterize building materials demands and operational energy consumption and their related carbon emission in Shanghai. The results indicate that the total carbon emissions from the life cycle of civil buildings in Shanghai exhibit a fluctuating downward trend, decreasing from 40.23 million tons (Mt) in 2022 to 32.60 Mt by 2060. Building energy-related carbon emissions account for the largest proportion (80% of the life-cycle emissions), far exceeding the emissions from building material production. Cement, steel, and bricks are the primary sources of embodied carbon emissions, accounting for 43%, 31%, and 13%, respectively. To mitigate carbon emissions, we propose five strategies for sustainable building, including material efficiency, energy efficiency, renewable energy substitution, electrification rate, and deep decarbonization of electricity. Under the high-efficiency reduction scenario, building carbon emissions could be reduced by 69.27% compared to the baseline scenario. Among the strategies, deep decarbonization of electricity and material efficiency yield the most significant emission reductions, contributing 46% and 12%, respectively. As the power supply undergoes rapid decarbonization, operational carbon emissions in Shanghai’s residential sector are transitioning from electricity-related indirect emissions to direct emissions from fossil fuel combustion. These results indicate that core mitigation strategies should focus on deep power-sector decarbonization and improvements in material efficiency, while simultaneously coordinating a phase-down of on-site fossil-fuel use through electrification and clean-fuel substitution in Shanghai’s building sector.
 

Building material demand, operational energy consumption, material flow analysis, life cycle assessment, building carbon emissions, Shanghai