Net Zero Framework – International Maritime Organisation

The International Maritime Organisation (IMO) approved in April 2025 its new Net Zero Framework, a regulatory instrument designed to steer international maritime transport towards net-zero greenhouse gas (GHG) emissions by around 2050. This framework, which will be integrated as a new Chapter 5 of Annex VI to the MARPOL Convention, will be formally adopted in October 2025 and enter into force in 2027.

It is structured on two principal axes: a required standard which establishes progressive limits on the GHG intensity of marine fuels, and a global economic system that applies a price to carbon- each ship will be assessed annually according to its emissions intensity performance. If the result is below the strict threshold set, it will generate ‘surplus units’ that it can retain, transfer to other ships or apply to subsequent years. Conversely, if it exceeds the limit, it must offset that excess by making contributions to the IMO fund or using units accumulated or transferred from other parts of its fleet. The Fund will collect and redistribute these payments to finance clean technologies, sustainable energy infrastructure and support the transition of developing countries. In this way, the system combines positive incentives with a flexible but mandatory compliance regime, promoting a gradual and economically balanced transition.

Though the IMO’s global framework and the European FuelEUMaritime regulations share technical principles, such as measuring emissions throughout the fuel lifecycle (well-to-wake) and technological neutrality, there are some fundamental differences between the two. FuelEUMaritime has a regional scope, focusing on routes to, from or within the EU, and applies more stringent targets from 2025. Meanwhile, the IMO system will apply globally from 2027, with a more phased timetable and a broader incentive scheme. In addition, the EU includes additional obligations such as the mandatory use of shore-side electricity for certain ships, measures not covered by the IMO framework. These differences create a need for harmonisation between the regimes.

Specifically, one of the main legal challenges today is to avoid double taxation on emissions from the same ship subject to both frameworks. Both the European Commission and the IMO have recognised the need for regulatory harmonisation to avoid this. The FuelEU regulation includes a review clause stipulating that the European Commission must periodically assess the progress of the agreements reached within the IMO and, if a binding and equivalent international regime is adopted, to adapt or remove the obligations laid down in European legislation. In addition, the emission monitoring systems used by the IMO and EU (MRV in the EU and DCS in the IMO) are being aligned, and institutional cooperation is planned to facilitate coordinated compliance and avoid duplication. Ultimately, the success of both frameworks will depend on their ability to coexist in a complementary manner, ensuring legal certainty, environmental effectiveness, and competitiveness for global maritime transport stakeholders.