Land Use Change Driving and Optimization of Carbon Budget in Hangzhou Metropolitan Area.

As climate change, such as global warming, has become a global environmental issue, clarifying the mechanism driving the carbon budget based on land use change has become an inevitable path to realize the "double carbon" goal. Based on the land use change characteristics in the Hangzhou Metropolitan Area from 1995 to 2020, this study employed the inventory accounting method, concentration index, and panel regression models to investigate the driving mechanisms of carbon budget dynamics influenced by land use changes. Moreover, the study utilized a "scenario-actor" policy analysis framework to propose low-carbon strategies through the integration of land use management within territorial spatial planning. The research findings were as follows： ① The carbon source capacity in the study area significantly surpassed its carbon sink capacity. The overall carbon budget concentration index had yet to exceed the 0.4 "alert threshold," with spatial concentration levels as follows： Hangzhou > Huangshan > Shaoxing > Quzhou > Jiaxing ≈ Huzhou. ② For croplands, larger areas and greater shape regularity contributed to a reduction in carbon budgets. Conversely, for constructed lands, expansive areas and increased fragmentation intensified the carbon budget levels, primarily driven by other urban land categories. ③ An increased proportion of croplands and higher land use heterogeneity promoted spatial equilibrium in carbon budgets, whereas the larger coverage and fragmentation of industrial and other urban lands led to an uneven spatial distribution of carbon budgets. ④ Low-carbon optimization of territorial space needs to adjust for the structure and form of carbon source functional land use as a key driver. At the policy implementation level, the central government and urban residents demonstrated strong support for low-carbon territorial control. However, cooperation from local governments, enterprises, and rural residents was suboptimal, necessitating complementary policies for effective guidance. This study holds practical significance for enhancing land use efficiency and promoting low-carbon urban development.