Carbon emissions from accumulated stock of building materials in China

The stock of building materials has critical impact on sustainable development and on the reduction of the carbon emissions of the construction industry; however, the accumulated stock of building materials and its carbon emissions remain uncertain. To clarify the stock situation regarding existing buildings in China and provide reference material to support reduction of building–related carbon emissions, the accumulated building material stock and associated carbon emissions were visualized and quantified in this study based on building vector data of 33 cities and nighttime light data. In 2017, 8.8 Gt of building materials in 161.1 billion m3 of accumulated building stock produced emissions of 17.8 Gt CO2eq. Concrete and cement represented the main material types and the greatest sources of emissions. Notable disparities were found in material stock among different regions, determined primarily by factors such as areas of urban and rural construction land, population, GDP, and landform. Spatial visualization of material carbon emission intensity in China revealed a pattern of “higher in the southeast, lower in the north and midland,” and showed three aggregation modes. The results of this study could serve as scientific reference for new policies regarding low–carbon building, thereby promoting carbon emission reduction and sustainable utilization of resources in the construction industry.