Material Metabolism of Infrastructure on an Inhabited Island: Resource Flow and Stock Growth

Island infrastructure material stock (MS) analysis reveals resource flow and accumulation, providing policymakers with insights for managing resources and planning. This study comprehensively analyzed the MS of infrastructure on Miao Island using a bottom-up approach and multi-source data. Key findings include the following: In 2020, the total in-use MS was 249.8 kt, with stone, gravel, and sand accounting for 80%. Transportation infrastructure held the largest share (40.8%). Over the past 40 years, Miao Island's infrastructure MS increased by 256%, with a net addition of 179.6 kt. The three distinct development periods were closely linked to China's reform and local stimulus plans. Miao Island has a lower construction intensity than urban areas, with a per capita MS growth rate of 10.12 t/yr. Despite this, future waste remains a challenge to the island's capacity. Given the constraints of limited investment due to population decline and the aging of in-use stock, island infrastructure should conform to local resource availability and long-term plans. Priority should be given to environmental compatibility, resilience to resource disruptions, and establishing a circular system to support sustainable island development.