Multi-typology and multi-scale maps of the in-use building material stock in China

Abstract

China's rapid urban expansion and population migration have led to a substantial increase in building material stocks (MS). Understanding these stocks is crucial for effective planning and managing the built environment. This study analyzed in-use building MS in China from 2000 to 2020 at different spatial scales and resolutions and employed typological data as a bridge addressing information gaps in non-residential buildings and the spatial scale discontinuity issue in MS analysis. At the macro scale, MS in China increased from 70 gigatons (Gt) in 2000 to 133 Gt in 2020. Non-residential and non-urban MS played substantial roles, constituting 41.8 % and 47.9 % in 2020, respectively. In highly urbanized regions, the proportion of residential building MS decreased due to the prevalence of more functional buildings. Some southern provinces had MS from rural areas even exceeding 50 %, emphasizing the importance of considering rural areas in construction resource management. At a high-resolution scale using GIS data, differences emerged between the analysis and statistical data. These differences, especially in estimating residential and commercial building MS, may be attributed to the mixed-use of building types in Chinese cities or unclear delineations of land use types. We advocate for further research to explore these variations, establishing consistent MS methods across different spatial scales and providing decision-makers with effective data support and analytical tools.