This study aims at informing the forthcoming IMO discussions on mid- and long-term emission reduction measures and their impacts on States, based on a transparent methodology. This is done by identifying the advantages and disadvantages of measures. The study has started out by developing a long list of all possible measures that are capable of ensuring that the shipping sector phases out its GHG emissions, as called for in the Initial Strategy. It then evaluates these measures on criteria of environmental effectiveness (i.e. the incentive provided to a fuel transition), cost-effectiveness, and predictability. The best-scoring measures have been further developed. Another objective of the study is to better understand the the possible impacts on States of a measure capable to decarbonise the sector based on a computable general equilibrium model supplemented with case studies. Moreover, the study analyses ways to address disproportionally negative impacts on States. This study analyses global measures which can be agreed and adopted by the IMO and follow from the Initial IMO Strategy on reduction of GHG emissions from international shipping. Regional measures and the possible interactions between regional measures and global measures are beyond the scope of this study.