The synergistic decarbonization potential from construction industry and upstream sectors with a city-scale: A case study of Hangzhou, China

How to reduce Carbon Emissions from the Construction Industry (CECI) is one of the key issues in China’s efforts to achieve its “dual-carbon target”. The Carbon Emission of the building Materialization Process (CEMP) is the main source of CECI, originating from both the upstream sector and the construction industry itself. Researching the synergistic decarbonization potential and reduction pathways of the construction industry and upstream sectors can help guide sustainable development. Focusing on the city scale, this study establishes a bottom-up framework based on system dynamics and carbon intensity methods to explore the possibilities of CEMP. The framework comprises a dynamic material flow analysis module and a carbon emission accounting module. The Logarithmic Mean Divisia Index (LMDI) method is employed to elucidate the emission reduction potentials of various factors. The results show that in the case of Hangzhou: (1) Without control measures, CEMP will reach a maximum of 25.1 million tons, and a substantial scale of 14.9 million tons remaining in 2060. (2) Through synergistic decarbonization, the cumulative emission reduction over the next 40 years could reach 323.4 million tons, and by 2060, CEMP could decrease to 3.7 million tons of CO2. Achieving carbon neutrality in the construction industry still requires carbon offsets from other sectors. (3) The decarbonization potential mainly comes from controlling the new construction area and carbon emission reduction in material production process, contributing 45.4% and 36.9%, respectively. This study reveals the significant pressure faced by the construction industry in achieving carbon neutrality. It also underscores that further controlling material demand and reducing the carbon intensity of materials is a prerequisite for Hangzhou's construction industry to achieve carbon neutrality.