Net‑Zero at Sea: MEPC 83, Delayed Decisions and the Future of the Maritime Industry - PART 1

What MEPC 83 and the latest IMO talks mean for shipping decarbonisation

The IMO’s Marine Environment Protection Committee (MEPC) has moved from high‑level ambition to detailed regulation, with MEPC 83 in April 2025 and the subsequent extraordinary session in late 2025 setting the direction of travel for the next decade. Together, they shape how quickly and how predictably shipping will decarbonise.

A new IMO Net‑Zero Framework

At MEPC 83, states approved draft regulations for a new ‘IMO Net-Zero Framework’ as a chapter in MARPOL Annex VI, intended to translate the 2023 IMO GHG Strategy into binding rules once adopted and in force. The framework has been approved in principle but, after a failed adoption attempt in October 2025, will not be formally decided until at least late 2026. The framework does two big things: it introduces a global fuel‑intensity standard for large ships and couples it with an economic mechanism that rewards over‑performance and penalises laggards.​

The fuel standard (often described as a Global Fuel Intensity, or GFI, regime) applies to ships of 5,000 GT and above, which account for the vast majority of international shipping emissions. It sets two trajectories (i) a “base” and (ii) a more ambitious “direct compliance” line, both benchmarked against a 2008 well‑to‑wake intensity figure, and tightens allowable emissions stepwise through the 2030s.​

Pricing carbon at the IMO level

MEPC 83 also backed an international pricing and reward system linked to the fuel‑intensity standard. Ships that outperform the direct target earn surplus compliance units; ships that underperform accumulate deficits and pay into a levy regime. The intent is to raise the cost of running inefficient, fossil‑heavy tonnage while channelling value toward low‑ and zero‑emission vessels and fuels.​

While the broad architecture was agreed in April 2025, the precise levy levels, revenue‑use rules, and distributional safeguards for developing states remain politically sensitive and subject to further negotiation. The extraordinary MEPC session later in 2025 failed to secure final adoption of the package, pushing the decision back by roughly a year and extending uncertainty for the market.​

[P44 NOTE: The basic price levels are set in the approved text: Remedial Units (RUs) at USD 100/t CO₂-eq (Tier 1) and USD 380/t CO₂-eq (Tier 2).]

Timelines: from approval to enforcement

Procedurally, MEPC 83 approved the mid‑term GHG measures as amendments to MARPOL Annex VI, with the original plan to adopt them at an extraordinary session in October 2025 and bring them into force 16 months later. The technical expectation has been that monitoring for the new fuel‑intensity regime would start in 2028, with data collected for ships ≥5,000 GT and used to verify compliance trajectories.​

The one‑year delay at the extraordinary session does not scrap the framework, but it complicates the calendar: legal adoption, entry‑into‑force dates and the start of mandatory compliance may now shift, even if the political direction, tightening GHG rules through the 2030s in line with net‑zero by 2050, remains intact. Shipowners planning around a 2027–2028 start for new requirements now face a compressed or adjusted timeline and will need to track subsequent MEPC sessions closely.​

Short‑term measures and CII under review

MEPC 83 did not only look at the future framework; it also took stock of the current toolbox. The Committee completed the first phase of its review of short‑term measures such as EEXI, SEEMP and the Carbon Intensity Indicator (CII), confirming that most implementation gaps and concerns cluster around CII. A workplan for Phase 2 of the review, starting in 2026 and expected to conclude by spring 2027, was agreed, to refine metrics, adjust reduction factors and ensure consistency with the new Net‑Zero Framework.​

At the same time, MEPC 83 adopted updated CII reduction factors for 2027–2030, effectively pre‑programming a steeper operational efficiency trajectory just as the mid‑term measures are due to bite. For operators, that means CII will not disappear; instead, it is likely to evolve and sit alongside the new fuel standard and pricing rules.​

Air pollution, ECAs and NOx rules

Beyond climate, MEPC 83 took several decisions that will tighten local air‑pollution controls. A headline outcome was the approval of a proposal to designate the North‑East Atlantic as an Emission Control Area (ECA) for sulphur oxides, nitrogen oxides and particulate matter, covering the EEZs and territorial seas of Greenland, Iceland, the Faroe Islands, Ireland, United Kingdom, France, Spain and Portugal. The associated MARPOL Annex VI amendments are to be adopted at a later session, with stricter fuel and engine standards expected to apply from the second half of the decade.​

The Committee also adopted amendments to the NOx Technical Code to better accommodate engines using non‑carbon or blended fuels and endorsed updated guidelines for selective catalytic reduction (SCR) systems. These changes are designed to give regulators and class societies clearer tools to certify alternative‑fuel engines while maintaining NOx controls as the fuel mix diversifies.​

Plastic litter, ballast water and biofouling

On the pollution‑prevention side, MEPC 83 adopted a 2025 Action Plan to Address Marine Plastic Litter from Ships, building on earlier strategies. The plan includes new work on the risks of transporting plastic pellets in containers and points towards future mandatory measures to reduce spill risks along the supply chain.​

The Committee noted ongoing work on the Ballast Water Management Convention and endorsed further experience‑building and guidance to improve implementation. It also agreed new work outputs to develop a legally binding framework for biofouling management, to assess implementation of the Hong Kong Convention on ship recycling, and to create guidelines on handling ammonia effluent from ships using ammonia as fuel.​

What this means for shipowners and policymakers

For shipowners, MEPC 83 and the subsequent extraordinary session confirm that the regulatory ratchet is tightening and that carbon will have an explicit cost at the global level, even if the exact numbers and dates are still being finalised. The combination of a fuel‑intensity standard, a pricing mechanism, evolving CII rules, and stricter ECAs will reward early investment in efficiency, alternative fuels and high‑quality data systems.

For policymakers and NGOs, the story is mixed: MEPC 83 delivered a historic package on paper, but political fault lines at the extraordinary session show how fragile consensus remains over revenue use, equity and impacts on food and energy security. The next MEPC meetings will be critical in turning approval into adoption and in ensuring that the Net‑Zero Framework delivers deep, real‑world emissions cuts by the 2030 and 2040 checkpoints rather than just another layer of complexity for the sector.

POLICY44 COMMENTS:

The latest MEPC developments leave the maritime industry in a paradoxical position: long‑term direction is clearer than ever, but short‑ to medium‑term risk has increased. On one hand, the Net‑Zero Framework and the GHG fuel‑intensity standard strongly signal that a global carbon price for shipping is coming, reinforcing the business case for efficiency, alternative fuels and high‑quality emissions data. On the other hand, the failure to formally adopt the framework and the resulting delay inject policy uncertainty into investment decisions on newbuilds, retrofits and fuel infrastructure, particularly for capital‑intensive projects with 20‑ to 30‑year horizons. In practice, this is likely to accelerate a two‑speed transition: leading owners, financiers and ports will continue aligning with the expected IMO regime and with regional schemes such as the EU’s, while more exposed or risk‑averse players may “wait and see,” potentially locking in transitional assets that are merely compliant on paper rather than resilient against tightening climate goals.

This analysis is provided for information purposes only. For further discussion or advisory support on these developments, please get in touch with our team.