Abstract

The plastics industry is now confronting the intertwined challenges of environmental leakage and greenhouse gas emissions. Although policy interventions may exert synergistic reduction effects, the magnitude of such synergy remains underexplored. Here, we systematically analyze the material metabolism, environmental leakage, and greenhouse gas emissions associated with 14 plastic types in China over the period 1992– 2021, and model the synergistic emissions reduction potentials and relative costeffectiveness of these plastics under 14 scenarios between 2021 and 2060. Our results show significant heterogeneity in historical emission trajectories across plastic categories. By 2060, the system change scenario demonstrates the greatest potential for synergistic emission reductions and optimized cost-effectiveness. Relative to the 2060 baseline scenario, the system change achieves an 80% reduction in plastic leakage and a 63% decrease in greenhouse gas emissions. These results provide a reference for the development of synergistic emission reduction strategies suitable for different plastic types and industries.