This paper discusses the issue of Impact Assessments (IAs) required for measures proposed under the IMO’s Initial IMO Strategy on reduction of GHG emissions from ships (Initial Strategy)3 . Definition and processes for preparing such IA’s are unclear and has become somewhat weaponized by different negotiating blocks, with some (including Pacific high ambition delegations) arguing the IA process should be an evolving one developed in parallel with the implementation of candidate measures, others arguing that no measure should be agreed until the comprehensive IA is completed and the impacts fully understood and provided for. The issue is closely connected with the concurrent debate over delineating Disproportionate Negative Impacts (DNI) arising from measures and the type and degree of compensation that might be afforded those adjudged to incur DNI…