Implementation of IMO rules on carbon emission from ships: a comparison between China and eu

As maritime carbon emissions continue to rise, the need to improve the effectiveness and adaptability of global decarbonization policies has become increasingly urgent. However, fragmented governance structures and limited coordination among major actors have hindered progress toward a unified international transition. This study applies the Policy Modeling Consistency (PMC) index model to quantitatively assess the maritime decarbonization frameworks of the International Maritime Organization (IMO), the European Union (EU), and China across nine structural dimensions. The findings indicate that the IMO framework achieves the highest structural consistency with a PMC score of 8.017, followed by the EU Emissions Trading System (ETS) with 7.925, while China’s national policies score 7.325. IMO policies emphasize global consensus and technical standard-setting but lack binding incentives, EU policies integrate legal mandates and market-based mechanisms with high coherence but heavy compliance costs, and China’s framework demonstrates flexibility and fiscal support but weaker enforceability and limited engagement. These results highlight the methodological value of the PMC model in diagnosing policy strengths and deficiencies and provide evidence-based recommendations for enhancing international policy harmonization, adaptive carbon pricing, and balanced regulatory—incentive design to advance a coherent and resilient global maritime decarbonization regime.