Quantification of the carbon emission of urban residential buildings: The case of the Greater Bay Area cities in China

Building sector plays a significant role in China's ambitous climate targets to peak carbon emissions (CEs) by 2030 and to realize carbon neutral by 2060. However, studies in characterizing the CEs of urban residential buildings from life-cycle perspective at regional level are still limited, especially for the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) in China. Here, life cycle assessment method and improved building stock turnover model were employed to quantify the annual CEs of urban residential buildings (including materialization CEs of the newly-built urban residential buildings, operational CEs of the existing urban residential buildings, and CEs generated from the demolition of the existing urban residential buildings) in GBA cities from 2000 to 2018. The results show that the total CEs increased dramatically from 44.5 Mt. CO2 e in 2000 to 75.1 Mt. CO2 e in 2018 with an annual growth rate by approximately 3%. The CEs from operation stage accounted for around 70%, and recycling building wastes could reduce 7.5% emissions. Compared with other bay areas globally, the operational CEs of urban residential building in GBA became the highest since 2014. Therefore, climate actions in energy saving and emission mitigation are required. Based on scenario analysis, we estimated that Huizhou city can reach the peak target by 2020 if taking some effective measures. These emission findings could provide data references and suggestions for the low-carbon development path for urban residential buildings in GBA and other global cities.