Also Published As: Climate Change and Ships: Increasing Energy EfficiencyPolicy makers and stakeholders have identified a range of near-, medium- and long-term mitigation options that are available to slow the growth of energy consumption and CO2 emissions from marine shipping. While the technologies and operational measures for ship-based CO2 reduction potential have been well documented, the reduction cost calculations remain sparse. This paper provides examples (using available data) of the application of methodologies to calculate the marginal abatement cost of CO2 reduction technologies and operational measures, and compares them under policy and economic contexts.