Quantifying the Carbon Footprint of Newly-Constructed Buildings by Using Life Cycle Assessment: A Case Study of Shenzhen City, China

China’s building construction sector accounts for almost half of the world’s building construction by floor area. Associated with the construction of the Guangdong-Hong Kong-Macao Greater Bay Area (GBA, including 11 cities) driving forward, there will be over one trillion yuan to boost urban construction and development in the coming decade. However, the booming of the construction sector will inevitably consume a large number of resources and energy. How to build the GBA sustainably is full of challenges. Take Shenzhen city as an example, which plays a leading role in building GBA; this study is designed to quantify environmental impacts (measured by carbon footprint, CF, or CO_2eq) of newly-constructed buildings in Shenzhen by using Life Cycle Assessment (LCA) method. The results show that CF has fallen sharply from a peak of 12 million tonnes (Mt) in 2003 to around 2.02 Mt in 2017 because of the fast decrease of buildings’ construction activities, which is associated with the decline of the number of the new permanent population. Residential building accounts for the largest share (50.4%) of the CF since it is still the main driver in Shenzhen city. The largest proportion of emissions comes from the embodied emissions of building materials, accounting for 87%. Meanwhile, this study took green buildings into considered and quantified the CF reduction from 2012 to 2017 to examine the development of green building practices in Shenzhen city. Although the reduction rate of the CF has risen continuously with the application of green buildings, the reduction in the rate of the CF was only 0.5% in 2017. The minimum requirements for green buildings in material saving and material resource utilization aspects should be further improved. Overall, these findings could provide not only technical, scientific evidence for policy-makers to promote the sustainable development of the building sector in Shenzhen and GBA, but also illustrate sustainable transition in other cities.