Using Material Flow and Stock Indicators to Evaluate Urban Allometry: Evidence from the Beijing-Tianjin-Hebei Region

The growing urban population is intensifying global resource shortages. It is essential for scholars and policymakers to better understand the material-based metabolism of cities for sustainable urban resource management. Taking the Beijing-Tianjin-Hebei region of China as a representative case, this study quantifies domestic material consumption (DMC) and material stock (MS) and reveals the dynamics of the material-based urban metabolism of cities during 2000 to 2017 based on the allometric scaling law. The results show that the DMC and MS of each city exhibited an overall increasing trend during 2000 to 2017, with Beijing, Tianjin, Shijiazhuang, Baoding, Handan, and Tangshan having larger material bases than the other cities. Cities at different stages of development usually follow different material-based allometric scaling law relationships. Most cities in this region (9 out of 13) follow a superlinear relationship, indicating excessive consumption of resources in these cities. The scaling coefficient of Beijing is most similar to the value (0.75) that has been observed in many types of biological research, which suggests that Beijing has reached a relative stabilization stage of development. This study provides key points for future resource allocation and industrial optimization related to urban material metabolism in the Beijing-Tianjin-Hebei region. The findings of this study can enrich the theoretical and empirical bases for urban allometry research and provide urban managers with additional insights for consideration to achieve sustainable urban resource management.