An integrated analysis of input and output flows in an urban carbon metabolism using a spatially explicit network model.

An integrated analysis of urban carbon metabolism from both input and output perspectives can present new insights to support carbon mitigation. In this study, we combined a previously developed spatially explicit network model with an analysis of carbon sequestration and emission by different land use or cover types, and illustrate its use by examining carbon flows in Beijing, China, from 1990 to 2015. The goals were to characterize the temporal changes of the integrated (total direct + indirect) flow structure by applying ecological network analysis and to identify the structure of the urban metabolism by analyzing temporal and spatial changes of the integrated flows. The results showed that the similarity between input and output trophic structures and their spatial pattern indicate increasingly carbon-balanced urbanization by Beijing. The balanced input and output flows for the transportation and industrial land and cultivated land played key roles in forming a central area of aggregated carbon flows between the city's peripheral plains, which also resulted in similar trophic structures for inputs and outputs. Understanding the evolution of the integrated flows during urban development provides a more solid empirical basis for regulating land-use change, improving land consolidation, and reducing carbon flows. Image 1 [ABSTRACT FROM AUTHOR]