Land consumption in cities: A comparative study across the globe

Land consumption delineates how effectively we use our living space - whether wastefully in area or efficiently. As the United Nations (UN) projects 5.1 billion population will live in urban areas in 2030, it is crucial to measure, compare, and understand land consumption for our cities across the globe. Currently global approaches for land consumption analysis rely on settlement layers produced by remote sensing data and population data achieved by distributing census data over settlement layers. These layers, however, do not have sufficient spatial details to capture the intra-urban structural variability within a city. In this study, we develop a classification system that consistently produces accurate local climate zone (LCZ) maps at intra-urban scale for 40 cities using Sentinel data. We use the LCZ classes as proxies to disaggregate the global population grids (GHS-POP) to this intra-urban scale. With the refined data, we perform an intra-urban land consumption analysis for 40 cities across the globe. Our measurements shows that current per-city land consumption studies severely deviate from the intra-urban variability. We argue urban land consumption at global scale must proceed to an intra-urban resolution. In addition, our measurements also indicate that urban land consumption is differing immensely across the globe.