Weighing the global built environment: High-resolution mapping and quantification of material stocks in buildings

Buildings provide indispensable services for human well-being, but their construction and use are responsible for a substantial fraction of societies' resource requirements and greenhouse gas emissions. Mapping and quantifying the material stocks in buildings is a key research frontier in industrial ecology. Reliable and spatially highly resolved maps of material stocks in buildings worldwide are so far not available. Existing approaches based on nighttime light data allow large-scale coverage, but their spatial resolution is usually ∼0.5-1 km. Other methods using light detection and ranging (LiDAR) and cadaster data achieve higher resolution and accuracy, but do not allow wall-to-wall mapping of large regions. Based on high-resolution Earth Observation data combined with material intensity factors (kg per m³ of building volume), we quantify and map material stocks in buildings at the unprecedented resolution of 90 m globally. We distinguish 18 types of materials in five types of buildings. We find that global material stocks in buildings amount to 547 (391-672) Gt, approximately half of total global societal material stocks. We find highly unequal distributions of material stocks in buildings per capita and per unit area of each country. Our results agree well with previous detailed estimates of material stocks in buildings in dedicated regions or individual cities. Improved and harmonized material intensity factors emerge as a key research area for improving the accuracy of material stock maps. Our results are available as data products with high spatial and thematic resolution to facilitate future studies; for example, of secondary resource potentials. This article met the requirements for a gold-gold JIE data openness badge described at http://jie.click/badges. http://jie.click/badges.

The online version of this article (doi:10.1111/jiec.13585) contains supplementary material, which is available to authorized users.