Globally, urban areas are growing at a faster rate than their population, potentially reducing environmental sustainability due to undesirable land take in (semi)natural and agricultural lands. However, it is unclear to what extent this trend varies locally, which may hamper the formulation and implementation of local-scale policies in the context of the global competition for land. Here, we attribute built-up land change to population dynamics and changes in land take per person, for >75,000 administrative regions worldwide, typically representing municipalities or counties. Results show that changes in land take per person, expressed as the area of built-up land per capita, relate to 38.3%, 49.6%, and 37.5% of the total increase in built-up land during the periods 1975–1990, 1990–2000, and 2000–2015, respectively, but with large local variations. Interestingly, we find that centres of large cities densify in all three periods, while their rural areas show an opposite development, suggesting an urban polarization effect. We also find densification in many regions in the Global South that already have a high population density, leading to potential trade-offs in terms of human wellbeing. Therefore, our work provides novel insights into the debate on sustainable urban development at a global scale.

在全球范围内，城市地区的增长速度超过其人口的增长速度，由于不良的土地占用（半）自然和农业用地，可能会降低环境可持续性。然而，目前尚不清楚这种趋势在多大程度上因地而异，这可能会在全球土地竞争的背景下阻碍地方尺度政策的制定和实施。在这里，我们将建成区土地变化归因于人口动态和人均土地占有量的变化，在全球超过 75,000 个行政区域，通常代表市或县。结果表明，1975-1990年、1990年期间，人均土地占有量的变化，以人均建设用地面积表示，分别占建设用地总增量的38.3%、49.6%和37.5% –2000 年和 2000-2015 年，分别为 但有很大的局部差异。有趣的是，我们发现大城市的中心在所有三个时期都变得更加密集，而它们的农村地区则表现出相反的发展，表明存在城市两极分化效应。我们还发现，在人口密度已经很高的全球南方的许多地区，人口密度增加，导致人类福祉方面的潜在权衡。因此，我们的工作为全球范围内关于可持续城市发展的辩论提供了新的见解。