Characterizing temporal and spatial characteristics of urban building material metabolism and embodied carbon emissions through a 4D GIS-MFA-LCA model

Enhancing the understanding on the temporal and spatial distribution of urban building material metabolism is crucial for informing urban resource, waste, and environmental management. However, this endeavor is often impeded by inaccuracies and inconsistencies in the typology and material composition data of buildings. Taking Macao as a case, this study established a 4D GIS-MFA-LCA model and compiled a local material composition database to address these gaps, for a detailed characterization of the quantity, quality, and temporal-spatial distribution of the urban building stocks and flows in Macao. The results show that between 1980 and 2020, the building materials stock (BMS) in Macao increased from 6.3 to 55.1 Mt (equaling 1.1 to 14.7 Mt CO2 eq of embodied carbon emission), accompanied by corresponding increases of 0.03 Mt to 0.7 Mt of building waste (BW). The tourism and entertainment area exhibited the fastest increasing rate of BMS in Macao. IPAT analysis shows that the economy, population growth and demographic changes have been the driving forces for BMS in Macao. The results of this study can help cities take effective measures toward achieving a circular economy and highlight the role of such information and urban planning in urban building resource, waste, and management strategies.