Conference Agenda

As the world urbanises rapidly, cities experience unprecedented population growth, especially in poorer countries. In this paper, we study the potential trade-off in the use of urban land that comes with urban growth, namely between greenness and needed living and working space. We do so by building a novel and unique panel dataset combining gridded data on population, area, built-up surface and volume, urban greenness, and nighttime lights (as a proxy for economic activity). Our global sample covers over 1000 cities over the 1990-2020 period. Using our sample, we identify key global stylised facts, as well as main differences across world regions. Relying on panel-data econometric techniques, we provide estimates for the elasticity of economic activity and greenness to population density, and explore heterogeneities across income levels and different city sizes. Our findings suggest a trade-off between greenness and economic activity, mainly driven by (increasing) population density in cities. We also dig into different patterns of city growth and create a “Bright and Green Index” to categorize cities in our sample. We find cities in upper-middle income countries to have the largest improvements in the index, with large cities in low-income countries doing significantly worse. Our analysis provides insights to explain these differences and on the potential role of public policy to make cities bright and green.