The International Maritime Organization (IMO) has hit a pause in its efforts to introduce legally binding net zero rules for global shipping after delays to the formal adoption of its new greenhouse gas regulations in October 2025.

The setback comes six months after the IMO’s Marine Environment Protection Committee (MEPC) approved a draft package of measures that would, once implemented, become the world’s first legally binding net zero framework across an entire global sector. The October delay follows growing political divisions over emissions pricing, including opposition from the United States, which has warned that a global levy on shipping could impact trade.

What Was Agreed in April 2025

In April 2025, during the 83rd session of the MEPC, the IMO approved draft amendments to MARPOL Annex VI setting out a new Chapter 5 to cut greenhouse gas emissions from international shipping to net zero by or around 2050.

The framework centres on two main measures:

  • A mandatory global marine fuel standard that limits the greenhouse gas intensity of fuels used at sea and gradually tightens those limits over time. Ships that fail to meet the targets will need to buy “remedial units” to offset excess emissions, while those operating on low or zero emission fuels will be able to earn or trade surplus units. 
  • A global emissions pricing mechanism that creates an economic system where payments based on emissions are collected into an IMO Net Zero Fund. This fund will support innovation, training and infrastructure and help developing countries transition to cleaner shipping.

The regulations are expected to apply to large vessels over 5,000 gross tonnes, which account for around 85% of global CO₂ emissions from international shipping. Once enforced, they will reshape how carbon performance affects both cost and competitiveness across the sea freight industry.

Formal Adoption Delayed

The IMO had planned to formally adopt the new rules at an extraordinary MEPC session in October 2025 but that milestone was not reached.

While the draft framework remains approved in principle, member states were divided over key details, particularly around how emissions pricing would work and how the fuel standard would be verified and enforced. Under MARPOL’s amendment procedures, formal adoption requires support from at least two thirds of member states representing half of global shipping tonnage, a threshold that was not met at this session.

Some nations raised concerns about the potential cost burden for developing economies, the readiness of global fuel supply chains and the complexity of implementation.

Political factors also played a part in the delay. The United States, supported by several trading partners, opposed the proposed emissions pricing mechanism, arguing that it would act as a global tax on shipping and place an unfair cost burden on certain economies. The stance came amid threats of retaliatory tariffs from the U.S. administration if the measure was approved. The pressure contributed to the decision to defer the vote and continue discussions into 2026.

As a result, the IMO has postponed formal adoption to allow further consultation and technical work before the next MEPC session in 2026.

What It Means for Shipping

Although the delay extends the timeline, the direction of travel remains unchanged. The fuel standard and emissions pricing system are still expected to form the foundation of the IMO’s long term decarbonisation strategy.

The additional time gives the industry an opportunity to prepare more thoroughly by refining data collection, improving energy efficiency planning and engaging in discussions around fuel certification and carbon accounting. Many carriers continue to invest in lower emission vessels and alternative fuels, recognising that the shift towards net zero shipping is now a question of when, not if.

Conclusion

While formal adoption of the IMO’s net zero framework has been postponed, the momentum behind decarbonisation in shipping continues to build. The next year will be crucial as technical work and negotiations continue ahead of the 2026 vote.

We will continue to monitor developments closely and keep customers informed as the regulatory framework progresses and as the industry moves step by step towards a cleaner, lower carbon future for global trade.