Transforming food systems toward carbon neutrality on a rapidly developing tropical island

Tropical islands are highly vulnerable to climate change, yet their food systems are increasingly contributing to greenhouse gas (GHG) emissions. Here, we quantify long-term emissions and carbon sequestration of the food system on Hainan Island using a life cycle assessment (LCA) framework covering 1952–2020, together with scenario projections to 2060. We find that Hainan Island’s food system shifted from a net carbon sink to a major emission source over the past seven decades, with gross emissions rising from 3.29 Mt CO 2 eq in 1952 to 15.13 Mt CO 2 eq in 2020, accounting for approximately 35% of the island’s total emissions. This transition was driven primarily by fertilizer-intensive tropical crop production, aquaculture expansion, and export-oriented agriculture. Scenario analysis shows that government management alone cannot deliver deep mitigation, whereas combining technological optimization with a structural shift from export-oriented production toward regional self-sufficiency could convert the food system into a substantial net carbon sink. Under this transformation scenario, the food system could achieve an absolute net sequestration of 13.55 Mt CO 2 eq by 2060, corresponding to a 20.33 Mt CO 2 eq reduction in net emissions relative to the BAU scenario. Our findings demonstrate that food systems on tropical islands can play a pivotal role in achieving carbon neutrality through coordinated technological, structural, and trade-related interventions.