Tripartite evolutionary game analysis of ports and shipping enterprises under carbon trading mechanisms: Incentives and policy implications

In the realm of global climate governance, the carbon trading mechanism has become a key policy tool for curbing carbon emissions. As major contributors to maritime carbon output, ports and shipping enterprises display complex strategic behaviors shaped by both government regulation and market incentives. This study develops a tripartite evolutionary game model to examine the dynamic interactions among governments, port enterprises, and shipping companies within a carbon trading framework. MATLAB simulations show that the system converges to a stable equilibrium with passive government supervision and voluntary emission reductions by both enterprises. Subsidies effectively lower abatement costs and promote low-carbon practices, while higher fines enhance reduction incentives and increase the likelihood of oversight. Rising abatement costs, however, reduce firms’ willingness to act, with port enterprises showing sharper declines than shipping firms. These findings underscore the potential of market-based mechanisms to align stakeholder incentives, and offer practical policy guidance for advancing carbon neutrality in the maritime sector.