Territorial Ecological Restoration with a High-carbon Storage Focus in the Beibu Gulf Urban Agglomeration of China: Insights from Carbon Metabolism Spatial Security Patterns

This study focuses on urgent research on restoring and enhancing carbon storage capacity in the Beibu Gulf Urban Agglomeration of China, a key area in the 'Belt and Road' Initiative, which aligns with carbon peaking and neutrality goals. This research analyzes the spatial characteristics of carbon metabolism from 2000 to 2020 and uses models to identify stable carbon sink areas, positive carbon flow corridors, and carbon sequestration nodes. The goal is to construct a carbon metabolism spatial security pattern (CMSSP) and propose territorial ecological restoration strategies under different development demand scenarios. The results show the following: 1) in 2020, the study area's carbon sink decreased by 8.29 x 104 t C/yr compared with that in 2010 and by 10.83 x 104 t C/yr compared with that in 2000. High-carbon sinks were found mainly in mountainous areas, whereas low-carbon sinks are concentrated in urban construction land, rural residential areas, and land margins. 2) From 2000 to 2020, the spatial security pattern of carbon metabolism tended to be 'high in the middle of the east and west and low in the gulf.' In 2000, 2010, and 2020, 16 stable carbon sinks were identified. The carbon energy flow density in Guangxi was greater than that in Guangdong and Hainan, with positive carbon flow corridors located primarily in Guangxi and Guangdong. The number of carbon sequestration nodes remained stable at approximately 15, mainly in Guangxi and Hainan. 3) Scenario simulations revealed that under the Nature-based mild restoration scenario, the carbon sink rate will reach 611.85 x 104 t C/yr by 2030 and increase to 612.45 x 104 t C/yr by 2060, with stable carbon sinks increasing to 18. In the restoration scenario based on Anti-globalization, the carbon sink will decrease from 610.24 x 104 t C/yr in 2030 to 605.19 x 104 t C/yr in 2060, with the disappearance of some positive carbon flow corridors and stable carbon sinks. Under the Human-based sustainable restoration scenario, the carbon sink area will decrease from 607.00 x 104 t C/yr in 2030 to 596.39 x 104 t C/yr in 2060, with carbon sink areas fragmenting and positive carbon flow corridors becoming less dense. 4) On the basis of the current and predicted CMSSPs, this study explores spatial ecological restoration strategies for high-carbon storage areas in bay urban agglomerations at four levels: the land control region, urban agglomeration structure system, carbon sink structure and bay structure control region.