Carbon Sequestration Potential of Rooftop Greening in Chinese Residential Communities and Its Spatial Variation Drivers

Current research on rooftop greening carbon sinks is mostly concentrated at the urban scale or in individual case studies, lacking refined nationwide assessments at the residential-community level. Based on high-precision, building-level rooftop vector data from the CMAB dataset, combined with provincial-level correction factors, this study estimates the carbon sink potential of residential rooftop greening across 31 provincial-level regions in China for 2021. Based on four working hypotheses, the optimal-parameter geographical detector model is applied to identify driving factors. The results show that (1) the potentially available roof area for greening in residential communities is approximately 620,000 ha. The annual carbon sink under the shrub scenario is 49.0% higher than that under the grass scenario, with a corresponding economic value of CNY 8.44 × 108–1.257 × 109; (2) The spatial pattern is characterized by “high in the southeast and low in the northwest” The southeastern half contributes over 96% of the national total carbon sink, while the carbon sink efficiency of the northwestern half is only 1/16 of that in the southeast; (3) The planting pattern exhibits clear regional differentiation, with shrubs being more suitable in the south and grasses in the north, but this conclusion is constrained by management intensity and structural load-bearing capacity; (4) Temperature and precipitation are the dominant natural drivers, and their interaction with economic factors constitutes the strongest explanatory combination. The findings provide refined baseline data for differentiated low-carbon community renewal, and future research should integrate IoT monitoring and eddy covariance measurements to calibrate the NEP coefficients used in this study.