This report examines what is needed to decarbonise international shipping by 2035. Zero carbon emissions from shipping within this timeframe is one of the proposed levels of ambition in the context of the International Maritime Organization’s “Initial GHG Strategy”, due to be agreed in 2018. Using the ITF International Freight Model, the report provides an updated baseline scenario for the development of emissions to 2035 and gives an overview of measures that can effectively reduce shipping emissions. Using different combinations of these measures, it charts possible decarbonisation pathways and reviews the conditions for implementation. The report concludes with recommendations on policies to incentivise decarbonisation.