An economy-wide material flow analysis of Tonga: circularity and the challenges of sustainable transition in Pacific small island developing states

The SIDS Accelerated Modalities of Action (SAMOA) Pathway (2014) supports sustainable development in Pacific small island developing States, yet Tonga lacks circularity metrics to inform its nationally determined contributions. This study quantifies the circularity rate and socioeconomic metabolism of Tonga using economy-wide material flow analysis, integrating data from the International Resource Panel with national statistics. Findings reveal high import dependence and zero circularity, with excess biomass waste left unutilized rather than converted into fertilizers or energy. The study highlights the potential for biomass valorization, and it recommends policies to reduce import reliance, enhance material efficiency and promote a circular economy to challenge the country’s linear consumption model.