Incentive-driven evolutionary game for maritime decarbonization: Evidence from Shanghai Port

Maritime transport underpins global trade, but remains a major source of greenhouse gas emissions, posing challenges for coordinated decarbonization. This paper develops a four-stakeholder evolutionary game model (4S-EGM) to analyze strategic interactions among the International Maritime Organization (IMO), port states, terminal operators, and shipowners, with the port state as the central decision-maker. The model integrates regulatory enforcement, financial incentives, and infrastructure investment and is contextualized through liquefied natural gas (LNG) retrofitting, with parameters referenced to Shanghai Port. Replicator dynamics, stability analysis, and sensitivity analysis are used to identify conditions supporting cooperation. The model evaluates the joint effects of green subsidies, carbon-related market benefits, initial conditions, and profit-sharing arrangements. The results show that cooperation depends on coordinated incentives, initial-condition path dependence, and contractual alignment through profit-sharing. Conditional parameter-sensitivity analysis further indicates that, under a supportive incentive configuration, full cooperation remains unchanged under moderate variations in most examined parameters except the subsidy and carbon-related market benefit. However, cooperation is not unconditional: the system does not reach full cooperation when these incentives are removed, while excessive subsidy costs may disrupt it. The findings emphasize combining sufficiently strong incentives with fiscally sustainable subsidy arrangements and provide scenario-based policy implications for coordinating stakeholder actions in transitional-fuel adoption and maritime decarbonization.