A spatially-explicit assessment on equality of Urban Green Space Coverage across 32 major cities in China

Abstract. Greenspace is an important urban component for providing ecosystem service and protecting human health. And the need for “providing universal access to greenspace for urban residents” has been specified in the 11th Sustainable Development Goals (SDGs11.7). Yet, the inequality of per-capita urban green space has not well understood in a spatially-detailed way. Therefore, in this study, we estimated per-capita urban green space at 30-meter sub-pixel level from our generated urban green vegetation fractions dataset, which exhibited a generally consistent agreement with estimated fractions from high-spatial resolution Google earth images (RMSE ranged from 10.41%~12.09%). And then quantified the spatial gradient change along the urban center-edge for 32 major cities in China, as well as their inequal access for urban residents. Our results indicate: 1) Urban green space generally decreases along the gradient from city centers to the urban fringe. However, the trends vary among 32 cities, exhibiting either monotonic, power-law decline or hump-shaped patterns. 2) Per capita urban green space in the urban core are generally lower than those in fringe for over 80% of case cities. 3) For 32 major cities, per capita urban green space inequality in eastern coastal China (e.g., Guangzhou) were lower than other central and western cities (e.g., Guiyang and Zhengzhou), due to better spatial alignment between green spaces supply and population demands. 4) Economic development (GDP) and urbanization (built-up area) are two key factors influencing the distribution of green space. These findings highlight the necessity of balancing efficiency and equity for urban planning, particularly through optimized greening policies for mitigating ecosystem service disparities and achieving sustainable development goals.