Multi-sectoral efforts are required for decarbonising the building sector: a case in Hong Kong

Decarbonising the building sector involves collaborative efforts from multiple sectors. Previous studies only focused on carbon mitigation within individual measures, impeding the interconnections within various stages, contributing sectors, and measures. We propose an innovative “stage-sector-measure” framework for evaluating the carbon mitigation effects of the building sector and apply it to Hong Kong. Results show carbon emissions of Hong Kong’s building sector will decrease by 84.4% in 2050. Electricity is the most significant contributing sector, accounting for 71.8% of accumulative mitigation effects of Hong Kong’s building sector. Regarding measures, cleaner production of concrete and steel represents 62.9% of mitigation effects in material production stage, while alternative fuel mix and carbon capture and storage account for 42.2–87.7% of those in other stages. By clarifying the relationships among the stages, contributing sectors, and measures, we identify the mitigation mechanism of the building sector and reveal the significance of multi-sectoral efforts in its decarbonisation.