[Land Use Carbon Metabolism Analysis of Guangzhou Based on Ecological Network Utility and Considering Urban Green...

Urban green space is included in the research framework of land carbon metabolism， and the relationship between land use carbon metabolism and carbon balance is decomposed from the perspective of ecological network， which provides a scientific basis for the optimization of land use structure and urban low-carbon development. Taking Guangzhou as an example， we obtained urban green space data through supervised classification and integrated multi-source data， systematically measured the carbon flux in the vertical direction， constructed a carbon flow model to analyze the spatial and temporal pattern of horizontal carbon flow， and applied the ecological network analysis method and ecological utility function to explore the comprehensive impacts of the land use changes on carbon metabolism. The results showed that： ① The net carbon flux of land use in Guangzhou was negative from 2000 to 2021， and the offset ratio of carbon sequestration to carbon emission decreased from 14.23% to 5.58%. The imbalance of carbon metabolism was exacerbated by the growth of carbon emission from transportation land， urban land， and river channel. ② The net carbon fluxes of the four time periods were negative， and the positive carbon fluxes were 4.73， 1.39， 1.42， and 1.59 times of the negative carbon fluxes， respectively. The positive carbon flow mainly originated from the conversion of industrial land to urban land and urban green space， while the negative carbon flow mainly originated from the conversion of cropland， forest land， and urban green space to industrial land and transportation land. ③ From 2000 to 2015， the dominant ecological relationship was the control of exploitation， which turned to a competitive relationship from 2015 to 2021， and the ecological utility function showed a tendency of increasing and then decreasing， with an average value of 0.77， which was less than 1， indicating that the comprehensive utility of land use change on carbon metabolism was negative. ④ The ecological relationship of carbon metabolism of land use in Guangzhou had obvious spatial and temporal heterogeneity， presenting the evolutionary characteristics of the development of the periphery of the central urban area to the suburban area. In the future， the land use structure and layout should be optimized， and nature-based solutions should be explored to promote the balance of regional carbon metabolism.