Modeling China carbon-certified garlic supply chain under EU low-carbon policies: evolutionary game insights into investment decisions and consumer preferences

In the context of stricter EU low-carbon policies and increasing consumer demand for sustainable products, this study investigates the evolutionary dynamics of the carbon-certified agricultural export supply chain between China and the EU. A four-party evolutionary game model is developed to analyze the strategic interactions among Chinese garlic suppliers, Chinese export manufacturers, EU suppliers, and EU consumers. Equilibrium and stability analysis are combined with numerical simulations to examine the dynamic evolution of strategic choices under different parameter settings. The results identify threshold conditions under which the supply chain converges to a full green equilibrium, stabilizes at a partially green state, or remains non-certified. Stronger consumer green preference and tighter trade-policy pressure jointly increase the likelihood of a certified low-carbon equilibrium, whereas high certification costs or weak market signals tend to sustain a high-carbon outcome. The findings further show that small changes around key parameters, such as certification cost, tariff pressure, and preference intensity, can trigger regime shifts in long-run strategies. These results provide actionable insights for policymakers and managers on how to align incentives and market signals to facilitate low-carbon transitions in cross-border agri-food supply chains.