Review of spatial analysis of urban carbon metabolism

Urban areas have contributed 75% of the global CO2 emissions. Therefore, seeking global carbon reduction solutions from the perspective of city has become a focus of decision-makers in charge of environmental protection. The carbon emission reduction potential in land management and spatial adjustment has become an important mean for achieving regional and global sustainable development. In this paper, we systematically review and synthesize four main aspects of urban carbon metabolism spatial analysis, namely: (1) advances in urban carbon metabolism, (2) carbon accounting based on land use and cover change, (3) spatial distribution of urban carbon metabolism and influencing factors, and (4) forecasting based on land use change (Land Use and Cover Change LUCC). In addition, we point out current deficiencies in the study of urban carbon metabolism, such as incomplete process analysis and lack of spatial display. Based on previous research, we propose a spatial analysis-centric outlook on urban carbon metabolism, including the following key approaches: (1) future researchers should simultaneously consider natural and socioeconomic components, as well as vertical (flows from land to atmosphere) and horizontal (flows among different land use types) carbon flows, to obtain a more complete picture of the entire urban carbon metabolism system; (2) carbon metabolic spatial mapping can be implemented in patches to better serve government's goals for optimal regulation and spatial planning; (3) researchers should refine current urban-scale research, also expanding it to the metropolitan (i.e., urban agglomeration) scale, to establish multi-scale, multi-level, and organic network structures, and study the spatial distribution pattern of carbon metabolism within and among cities and metropolitan areas, which will lay a scientific foundation for urban, regional, and national sustainable development.