The IMO Net Zero Framework delay: what MEPC ES.2's adjournment means for ammonia energy timelines

The sequence of events at the IMO in 2025 represents the most significant regulatory setback for the ammonia shipping fuel sector in several years, and also — depending on how MEPC 85 in autumn 2026 unfolds — potentially a temporary one. Understanding precisely what happened, and what the different possible outcomes mean, is essential for any participant in the ammonia energy supply chain currently making investment decisions with long time horizons.

What was agreed at MEPC 83

The Marine Environment Protection Committee's 83rd session in April 2025 produced an outcome that was widely regarded as historic. After several years of negotiation, IMO member states approved draft amendments to MARPOL Annex VI constituting the Net Zero Framework — a package of measures including a global fuel standard setting annual greenhouse gas intensity reduction targets through 2035, and an emissions pricing mechanism that would generate revenues to fund zero-emission fuel incentives and support an equitable transition for developing nations.

The framework was imperfect by most analysts' assessments. Its GHG intensity targets, while binding, were calibrated in a way that does not put shipping on a trajectory consistent with the IMO's own 2023 strategy goal of net-zero emissions close to 2050. The pricing mechanism — a carbon credit trading system — was seen by some as too complex and by others as insufficiently ambitious in the carbon price it would establish. Nevertheless, the outcome at MEPC 83 was broadly welcomed across the shipping industry as the first global, binding regulation to address maritime decarbonisation at sector level, and as the framework on which zero-emission fuel markets — including ammonia — could be built.

What happened at the extraordinary session

The draft legal text approved at MEPC 83 was circulated to member states for review ahead of an extraordinary MEPC session scheduled for October 2025, at which formal adoption was expected. Adoption through the IMO's tacit acceptance procedure requires a two-thirds majority of member states and is typically a procedural step following political agreement rather than a site of substantive negotiation.

In August 2025, the United States signalled its opposition to the framework and indicated it could impose trade, port, and other restrictions on member states that voted in favour. When the extraordinary session convened in October 2025, Singapore and Saudi Arabia — supported by 57 other member states including Russia — proposed adjournment by one year. The motion carried. The session ended without adopting the framework, and formal adoption was deferred to MEPC 85, now scheduled for autumn 2026.

The US opposition has been characterised as ideological in origin — a position consistent with the broader posture of the second Trump administration on international climate agreements — rather than a principled objection to the specific design of the Net Zero Framework. Some countries that voted for adjournment have stated separately that they support the framework's objectives and voted to adjourn for process rather than substantive reasons. Whether those distinctions will matter when MEPC 85 convenes is an open question.

What the delay means for ammonia fuel investment

The Net Zero Framework was not the only driver of investment in ammonia as a marine fuel. The IMO's 2023 strategy, FuelEU Maritime in Europe, and the EU Emissions Trading System's full phase-in to shipping in 2026 all provide independent demand signals. Ammonia engine commercialisation by MAN ES, WinGD, and Wärtsilä proceeded through 2025 on schedules determined by technical development rather than regulatory timelines. The first ammonia-fuelled vessels are entering service regardless of what the IMO does in October 2026.

The delay is, however, a meaningful setback for several categories of investment decision. Shipowners evaluating fuel choices for orders with delivery dates in the 2028 to 2030 window were using the Net Zero Framework's fuel standard as one of the key inputs into their modelling. A binding global fuel standard that penalises high-GHG-intensity fuel creates a floor demand for zero-emission alternatives; without it, the business case for ammonia fuel — relative to continuing to operate on fuel oil or switching to LNG — weakens at the margin.

For ammonia bunkering infrastructure developers — the port terminal operators, storage providers, and ammonia importers who need to commit capital before ammonia vessel demand materialises — the delay extends the period of demand uncertainty that is already the central obstacle to early infrastructure investment. Port infrastructure for ammonia bunkering has a different timeline to vessel ordering: a terminal takes two to four years to permit and build, requires substantial capital, and needs contractual volume commitments before it can be financed. A one-year delay in the regulatory signal that drives those volume commitments compounds across the supply chain.

What remains at risk

The most acute risk from the adjournment is not a one-year delay in regulatory implementation but the possibility that some member states use the 2026 extraordinary session to reopen substantive elements of the framework text, rather than simply adopting what was agreed at MEPC 83. Several countries have submitted proposals ahead of MEPC 84 — the regular session scheduled for spring 2026 — that would weaken the fuel standard provisions or restructure the pricing mechanism. If those proposals gain traction, the framework that MEPC 85 considers could be materially different from — and weaker than — what was agreed in April 2025.

If the framework is adopted at MEPC 85 in the form agreed at MEPC 83, the regulatory trajectory for ammonia fuel remains broadly intact, delayed by approximately a year. Entry into force — which requires a minimum 10-month period following formal adoption under the IMO's tacit acceptance procedure — would then be targeted for 2028, with the fuel standard and emissions pricing applying from that year.

What first-movers should do

The short-term strategic conclusion for participants in the ammonia energy sector is that the regulatory tailwind from the IMO framework has not disappeared but has become less certain and more distant. The appropriate response is not to pause investment but to ensure that investment decisions made in 2026 are robust to a range of regulatory outcomes rather than dependent on a specific timeline.

For vessel owners, dual-fuel ammonia engine designs — which are now commercially available from all three major manufacturers — provide the most regulation-agnostic choice: they can operate on conventional fuel if ammonia supply is delayed, and on ammonia when supply is available and economics support it. For bunkering infrastructure developers, the EU regulatory framework — FuelEU Maritime, ETS, CBAM — provides a sufficient near-term demand signal for investments targeted at European trade corridors without requiring IMO adoption. For green ammonia producers with long-term contracts with European buyers, the CBAM and RFNBO frameworks already create a market in which cost-competitive green ammonia can find offtake.

The IMO process is not the only path to a functioning ammonia marine fuel market, and the sector's progress in 2025 demonstrated that supply chains, engines, and commercial structures can be assembled ahead of comprehensive global regulation. What the adjournment does is slow the rate at which that market develops to its potential scale — and increase the premium on the kind of early, high-conviction investment that creates the infrastructure on which broader adoption depends.