The International Maritime Organization (IMO) adopted a strategy to phase out greenhouse gas (GHG) emissions by mid-century. This strategy lacks teeth until IMO Member States agree on legally binding measures in April 2025. Whether they set up the shipping industry to deliver on its climate commitments will depend on what they decide. Delivering on the strategy would be a momentous win for climate action and multilateralism. Failure would further undermine the credibility of the United Nations and its specialised agencies (including the IMO) to tackle climate change. This article explains what this would take to succeed.