Fine allocation of sectoral carbon emissions at block scale and contribution of functional zones

The rapid development of cities has resulted in a substantial increase in carbon emissions, which has a detrimental impact on the environment. Previous studies had focused on large-scale carbon emissions; however, the carbon emissions from urban functional zones that consist of blocks as basic units have not been explored. In this study, we used Open Street Map (OSM) road and point-of-interest (POI) data to classify Shanghai into different functional zones and investigated their contributions to carbon emissions from various sectors. A top–down method was used to finely allocate the statistical data to different functional zones, and a random forest algorithm was used to investigate the contributions of different features to the regional carbon emissions. Among the 5677 units examined in this study, the majority belonged to residential zones, followed by commercial and industrial zones. The carbon emission contributions of the three zones were 26, 34, and 12%, respectively. With respect to sectors, higher carbon emissions originated from the residential and tertiary sectors, primarily concentrated in the urban centers and western city areas. Secondary and primary sectors followed suit, with the highest concentrations being from urban peripheries. This study can be used to optimize and rationalize the allocation of functional areas; notably, our study presents a novel direction for assigning carbon emissions responsibilities to different urban functions. Furthermore, the method presented in this study can be customized for carrying out analysis for other countries, with the aim of estimating and addressing carbon emissions on a sectoral basis.