Title: Estimation and mapping of the material stocks of buildings of Europe: a novel nighttime lights-based approach

Material Stock Assessments (MSA) form an essential component in our understanding of the functions of built infrastructure within the socioeconomic system and its environmental impacts. Scarce material stock data are a major impediment, and studies are often limited in scope, resolution, or both, and often employ ad-hoc methods hampering comparability between regions. In this study we describe the development of a method to estimate material stocks on a continental scale with a resolution of city districts and small settlements and its application to Europe. We use satellite-derived nighttime lights data to delineate distinct built-up areas. These areas’ radiance values serve as a proxy for built-up volume, estimated using cluster-based regressions with random resampling. Coupled with building intensities of different building materials, we derive a spatial MSA for Europe, presented in multiple levels of aggregation from city district to continental. The total material stocks of Europe are 109 billion tons, with an average of 37 thousand tons/km². The results reveal multi-level spatial patterns of material stock densities, enabling comparisons between and within regions and countries. The model offers good agreement with previous studies, highlighting its advantage in data acquisition, spatial comparability, and benchmarking abilities. The used data can be updated regularly, offering the ability of future exploration into spatiotemporal dynamics of material stocks.