Inequality in urban green provision: A comparative study of large cities throughout the world

Given the important role of urban green space (UGS) playing in sustainable cities, UGS has received extensive attention and study. However, most studies were limited to individual cities or regions and yielded inconsistent results due to the use of diverse data sources and methods, and little is known about the inequality in green provision at the global scale. In this study, we compared green provisions and inequality in 1013 cities (built-up areas >= 100 km2) around the globe utilizing the indicators of percentage of green area, green exposure, and Gini coefficient. Furthermore, their relation to demographic, geophysical and socioeconomic factors was estimated at the levels of the globe, geographical regions, and income divisions. We found that the large cities in high-income countries enjoy much more adequate and equitable UGS resources than that in low-income countries. In global context, population density is most strongly associated with UGS provision and inequality, while climate in-fluence UGS to a higher extent than human activities in most regions. The interactions with demographic or climatic factors have a relatively significant nonlinear-enhanced effect on UGS. Our findings can provide insights for greening interventions at regional and global scales.