Maritime emissions trading in the EU: Systematic literature review and policy assessment

The European Union Emissions Trading System (EU ETS) has been expanded to include maritime transport. Since 2024, large ships that stop at European Economic Area ports are subject to a carbon price under the EU's greenhouse gas emissions cap. To improve understanding about the goals and possible impacts of this EU policy expansion, the present article conducts a Scopus and Web of Science-based systematic literature review of peer-reviewed publications that assess the legal design or expected effects of EU maritime emissions trading. The relevant findings from 51 identified studies are categorized based on a framework of assessment criteria, which are systematically derived from the policy objectives outlined in the EU ETS Directive: emissions reductions, cost-effectiveness, economic efficiency, equity, and coherence. The aggregation of literature findings with a qualitative research synthesis provides a comprehensive up-to-date assessment of the maritime EU ETS, illuminating trade-offs between the pursued policy objectives and revealing gaps in existing knowledge. These findings suggest that the EU ETS can result in significant emissions reductions, at a lower overall cost compared to regulatory alternatives. It can also help to stimulate the adoption of technical and operational decarbonization solutions in maritime transport. However, uncertainties remain regarding the risk of carbon leakage, the uneven economic impacts of the EU ETS on certain countries, populations, and shipping segments, as well as its coherence with other domestic and international policies. This overview guides decision-makers in the first implementation stages of the maritime EU ETS and informs the design of similar market-based policies in other jurisdictions.