Integrating energy intensity heterogeneity into city-level energy related emission inventories: evidence from Guangdong

Reliable city-level energy use and energy-related CO₂ inventories are essential for evidence-based climate governance, yet city energy statistics by energy type and sector remain unavailable for most Chinese prefecture-level cities. Conventional top-down allocation (TDA) method based on province-average energy intensity are therefore widely used, but they assume that all cities within the same province have the same energy intensity because city-level energy intensity data were previously unavailable. This may lead to substantial deviations between the estimated results and actual city-level energy use. To address this problem, this study develops a modified TDA (MTDA) method by introducing the ratio of city-level to provincial energy intensity into the allocation coefficient. Applied to Guangdong province from 2010 to 2022, the method constructs continuous city-level energy-related CO 2 inventories for 21 cities. Benchmark validation against published city statistics shows strong agreement between the MTDA estimates and observed values ( R 2 = 0.99), supporting the reliability of the reconstructed inventory. The difference between MTDA and TDA increases with the deviation of city-level energy intensity from the provincial average ( R 2 = 0.908), indicating that the intensity adjustment captures inter-city heterogeneity. Based on the joint pattern of emission scale and carbon intensity, the 21 cities are classified into three categories: high emission scale-dominated cities, high emission intensity-dominated cities, and moderate emission cities. The results further show that, in Guangdong, urban energy system optimization, production-side industrial decarbonization, and low-carbon development-path guidance are the key mitigation directions for these three categories, respectively.