Enhancing the understanding of urban green space cooling effects in China’s major cities with a sub-meter dataset

Urban green space (UGS) plays a vital role in mitigating the urban heat island effect. Existing studies on its cooling impacts in major Chinese cities are limited by low- to medium-resolution data, small geographic coverage, and the inconsistent analytical framework, which hinder systematic, comparable, and large-scale assessment of UGS cooling effects. This study addresses these gaps by developing a sub-meter UGS dataset covering densely populated Chinese cities and employs econometric methods to assess its cooling effect while accounting for spatial and environmental heterogeneity. Results reveal an overall land surface temperature (LST) reduction of 2.972 °C associated with UGS presence, and a one-standard-deviation increase in UGS corresponds to an approximate 0.123 °C LST decrease. Beyond the overall effect, we observe substantial spatial variation: UGS cooling is stronger in public and residential areas, open and high-rise environments, higher elevations, and drier climates. However, extreme heat diminishes UGS effectiveness, highlighting the need to strengthen green infrastructure in hotter regions. Notably, super-large cities show weaker cooling despite considerable UGS coverage, indicating inefficiencies in UGS configuration. These findings underscore the dependence of UGS effectiveness on local climatic and geographical conditions and highlight the significance of high-resolution UGS data in serving as a foundation for evidence-based urban climate adaptation strategies. The dataset is publicly released to support future research in this area. Overall, this study advances the understanding of UGS as a nature-based solution and provides insights into enhancing urban resilience to climate change. • A national sub-meter UGS dataset for 49 China’s major cities was developed. • UGS cooling effects were assessed using econometric methods. • UGS lowers LST by 2.972 °C on average in China’s major cities. • Cooling effects exhibit obvious spatial heterogeneity. • Tailored green planning and high-resolution UGS data are essential.