Container shipping chain’s collusion strategy in carbon neutrality: A study based on tripartite evolutionary game model

Climate change is one of the most prominent environmental issues in the 21st century. The Chinese Government has developed dual carbon targets of peak carbon by 2030 and carbon neutrality by 2060. As one of the main sources of carbon emissions, transportation plays an important role in achieving the carbon neutrality. Facing intense market competition, container terminals and liner enterprises are motivated to collaborate to improve their profits. Meanwhile, the Port Authority plays an important role in supervising the container shipping chain’s collusion strategy to promote social welfare and achieve carbon emission reductions. This paper develops a tripartite game model to research the long-term effects of the Port Authority’s supervision of the container shipping chain’s collusion strategy. Under the premise that the container terminals’ net profits from the collusion strategy are greater than that from the non-collusion strategy, the stability analysis in four scenarios shows that the shipping chain tends to choose the collusion strategy, and the Port Authority tends to select a lax supervision strategy, regardless of the difference between the sum of penalties and subsidies and the increased profit of the shipping chain’s collusion strategy when the penalty received by container terminals is less than the Port Authority’s cost. Interestingly, there is no evolutionary stabilization strategy if the sum of penalties and subsidies is greater than the difference in the profits of the shipping chain’s collusion strategy. Finally, the number simulation verified the authenticity of the stability analysis. These results can guide and benefit relevant stakeholders in the container shipping industry to achieve carbon emission reductions.