Spatiotemporal evolution and driving mechanisms of urban land use carbon metabolism in the Guangdong-Hong Kong-Macao Greater Bay Area from 2000 to 2023

Against the background of rapid urbanization and the “Dual Carbon” goals, analyzing the impact mechanisms of land use change on carbon metabolism is crucial for regional sustainable development. Taking the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) as the study area, we integrate energy consumption data and the Forest Carbon Sequestration (FCS) model to clarify the land use carbon metabolism status based on Ecological Network Analysis (ENA), and systematically analyze the spatiotemporal evolution patterns of urban land use carbon metabolism, interactions between land types, as well as its driving mechanisms in the GBA from 2000 to 2023. The results show that: (1) Over the past two decades, land use changes have exhibited a significant characteristic of “natural land retreat and construction land expansion”, with areas of cropland, forest, and waterbody shrank by 16%, 4%, and 4% respectively, while urban land and industrial land increased by 50% and 438% respectively; 76% of the reclaimed land was transferred to construction land. (2) The imbalance of carbon metabolism was jointly affected by land use patterns and land use change processes: carbon emissions from energy consumption surged by 116%, while land carbon sequestration capacity decreased by 12%; in most periods, the negative carbon flow from land use change exceeded positive flows, with both showing sharp fluctuations. (3) Construction land in various cities dominated the carbon flow network through control or exploitation relationships, and the mutual transfer between industrial land and cropland is the primary driver; ecological land protection policies (e.g., the forest “in-out balance” scheme) effectively reduced the intensity of competition relationship. (4) The push-pull forces of land types demonstrate the dual effect of industrialization and urbanization, but their contribution has gradually weakened as the speed of urbanization declined in various cities; the proportion of the indirect carbon flow reached a maximum of 37% (2005–2010), indicating that the indirect impact of land use change cannot be ignored. This study deepens the understanding of the land-carbon interactions, reveals the implicit effects of the “policy implementation-land use change-carbon flow generation” transmission chain, and proposes a “construction land-cropland-ecological land” constraint system and a synergistic path of industrial land intensification and inefficient land ecological restoration. It provides methodological support for low-carbon governance at the urban agglomeration scale.