On 4 September 2026 an intersessional working group at the International Maritime Organization closed four days of talks in London on a set of draft regulations it has now been working through for more than a year. Its chair reported "a genuine willingness within the Group to make concrete further progress" and pointed the group towards putting improved text to the next session of the Marine Environment Protection Committee [source: IMO, 2026]. The same meeting summary records that the group ran out of time on the guidelines it was supposed to write, never reached the fuel life-cycle assessment item at all, and pushed both to its November session [source: IMO, 2026].
Those two facts, side by side, are the state of the world's first global carbon price for shipping. The text exists and it is specific. It was approved once, in April 2025. It has twice gone unadopted since: an extraordinary session convened to adopt it adjourned in October 2025, and MEPC 84 did not adopt it in April 2026 either. It has not been rejected.
That distinction gets collapsed in most accounts, and the collapse is where the confusion starts. Approved, adjourned and unadopted are three verbs belonging to three different meetings. A fourth verb, rejected, belongs to none of them. What follows is what the draft would actually require, why the Parties to MARPOL Annex VI cannot agree on it, and what is already running regionally while they try.
Three meetings, three outcomes — and not one was a rejection
MEPC 83, in April 2025, approved the draft new chapter 5 of MARPOL Annex VI, and the Secretary-General circulated the text days later under article 16(2)(a) of the convention [source: IMO, 2025]. Approval is a procedural milestone with no legal effect on any ship: it fixes the wording and starts the clock on the six months that must pass before a session can consider adopting it.
The session called to do that adopting was an extraordinary one, held in October 2025. It did not vote the framework down. It voted to adjourn itself, and the IMO's own announcement afterwards described talks resuming later rather than a decision taken [source: IMO, 2025]. Four days before it opened, the US State Department had said it was weighing visa restrictions on seafarers, additional port fees, and sanctions against officials in states backing the measure [source: U.S. Department of State, 2025]. The two events sit days apart in the record; the IMO has published no account linking them, and neither should be read as the cause of the other.
MEPC 84, at the end of April 2026, also ended without adoption. What it did instead was procedural: it created an intersessional working group, scheduled two meetings for it, and approved the terms of reference for the Fifth IMO GHG Study [source: IMO, 2026]. The first of those two meetings was the one that closed in September. The resumed extraordinary session now has a date, 4 December 2026, but the IMO attaches a condition to it — the session is "scheduled to resume on 4 December, subject to discussions at MEPC 85" [source: IMO, 2026]. Reading that as a scheduled vote is reading more than the sentence says.
What the draft text actually says
A carbon tax on every ship in the world does not describe this text, and the difference is not rhetorical. Two things need separating: which ships the chapter would reach, and what it would charge them for.
It does not cover every ship
Regulation 30 of the draft applies the chapter to ships of 5,000 gross tonnage and above on international voyages, with exclusions for certain categories [source: IMO, 2025]. That threshold is narrow in ship numbers and wide in emissions: the IMO puts the covered fleet at more than 85% of international shipping's CO2 emissions [source: IMO FAQs, accessed 2026-09]. The draft's own review clause, regulation 44, lists the possible application of the chapter to ships of 400 gross tonnage and above among the questions a five-year review would consider — a question for a later review, not the scope on the table now [source: IMO, 2025].
Two duties, one benchmark — and it is not a flat tax
A covered ship would carry two obligations at once: an annual greenhouse gas fuel intensity to meet, and a payment on the part of its emissions that falls short of it [source: IMO, 2025]. The intensity is measured well-to-wake, so emissions from producing a fuel count alongside emissions from burning it, and it is measured against the 2008 international average of 93.3 grams of CO2-equivalent per megajoule [source: IMO, 2025]. The draft then runs two tracks of annual reduction factors against that baseline, a base target and a stricter direct compliance target, and a ship that beats the stricter one earns surplus units valid for two calendar years instead of owing anything [source: IMO, 2025]. Nothing is charged on a ship's emissions as such. The charge attaches to the gap.
The price, and the three conditions attached to it
The draft names US$100 per tonne of CO2-equivalent for Tier 1 remedial units and US$380 for Tier 2 [source: IMO, 2025]. Three conditions travel with those numbers and are usually dropped. They are draft figures in a text that has not been adopted. They are initial prices, written for the 2028-2030 reporting periods only. And the draft does not say what follows: the Committee would have to settle the mechanism for setting prices from 2031 by 1 January 2028 [source: IMO, 2025]. A separate threshold, for the fuels the draft treats as zero or near-zero emission, tightens from 19.0 to 14.0 grams of CO2-equivalent per megajoule in 2035 — the lower figure is in the draft text but not in the IMO's public explainer [source: IMO, 2025; IMO FAQs, accessed 2026-09].
A fund whose allocation has not been written
Revenue would go to an IMO Net-Zero Fund, administered under a steering body, and the draft lists five broad uses for it, from research and infrastructure to support for developing states and a just transition for seafarers [source: IMO, 2025]. What it does not do is allocate. The shares between those uses are left to governing provisions still to be agreed [source: IMO, 2025]. For a state whose first question is what it would receive, the answer in the current text is a list of purposes rather than a number — which is one reason adoption has been hard.
Why there is still no agreement
The submissions to MEPC 84 divided four ways, and the span between the ends of that range is why the Committee has not been able to close [source: European Parliament, 2026]. In one session, one group asked for the Tier 1 price to be raised to US$300 per tonne while another asked for the pricing element and the fund to be removed altogether [source: European Parliament, 2026]. Those are not positions a chair splits the difference between.
The history of levy proposals runs across a similar spread, from about US$0.65 per tonne of CO2-equivalent in an industry proposal that was rejected in 2022 to the US$380 in the draft itself [source: European Parliament, 2026]. Industry is not aligned either: a European Parliament briefing records the International Chamber of Shipping favouring a simpler global levy, one classification society expressing reservations about how the text treats LNG, and another recommending explicitly that the IMO freeze the process [source: European Parliament, 2026].
Nor do positions map onto the caricature of a permanent bloc. The same briefing notes that the United States supported the 2023 IMO strategy, was absent from MEPC 83, and has opposed this framework [source: European Parliament, 2026]. Its stated objection is that the framework amounts to a tax on Americans imposed by an unaccountable body, and that the fuel standard favours technologies American industry does not lead in [source: U.S. Department of State, 2025]. The October statement also cited estimates of global shipping costs rising "as much as 10% or more" — a figure the statement does not source, and one to treat as an assertion rather than a measurement [source: U.S. Department of State, 2025].
The arithmetic of adoption
Adopting an amendment to MARPOL Annex VI needs a two-thirds majority of Parties present and voting [source: IMO FAQs, accessed 2026-09], which is why the October tally cannot be read as a verdict on the framework: that vote was on whether to keep sitting [source: European Parliament, 2026]. After adoption a different rule takes over. The amendment would enter into force — the IMO has indicated roughly 16 months after adoption — unless a third of the Parties, or Parties whose merchant fleets together make up at least half of world tonnage, object in time [source: IMO FAQs, accessed 2026-09]. The United States and Saudi Arabia have asked for that tacit procedure to be replaced with explicit acceptance, which would require states to opt in rather than to object [source: European Parliament, 2026].
While the global regime waits, a regional one is already running
Since January 2024 the EU has brought maritime transport into its emissions trading system, under a regulation and a directive adopted in 2023, for ships of 5,000 gross tonnage and above calling at EU ports [source: European Commission, 2026]. The system covers all emissions between two EU ports and at berth in them, and half of the emissions on voyages that start or end outside the EU [source: European Commission, 2026]. Allowance surrender was phased in rather than switched on, and methane and nitrous oxide join CO2 in the scheme from 2026. From January 2025 FuelEU Maritime added a limit on the greenhouse gas intensity of the energy used on board [source: European Parliament, 2026]. A price and a standard: the same pair the IMO draft would apply globally, already applied to one region.
The EU has also written the IMO into its own law. Both instruments contain review provisions referring to IMO progress, and the Commission has said it would review the status of relevant EU legislation once the IMO adopts the framework [source: European Parliament, 2026]. A revision of the shipping ETS was flagged for the third quarter of 2026 in the Commission's work programme; whether it has appeared is not something this article can confirm [source: European Parliament, 2026].
The regional version also shows what a regional version costs. A European Parliament briefing puts transhipment at as much as 90% of volumes at ports such as Algeciras and Piraeus, which gives carriers a reason to move it outside the EEA [source: European Parliament, 2026]. A 2022 study cited in the same briefing found that hubs outside the EEA become attractive at carbon prices well below EUR 25 per tonne of CO2 [source: European Parliament, 2026]. The EU's answer is a 300 nautical mile exclusion zone plus a list of neighbouring container ports, which currently has two entries, Tanger Med in Morocco and Port Said in Egypt [source: European Parliament, 2026]. Port associations and the European Economic and Social Committee have questioned whether that is enough. The UK and some African states are working towards pricing schemes of their own [source: European Parliament, 2026].
What the measured numbers say — and what they don't
The loudest objection is about cost, and the measured picture is thinner than the argument on either side suggests. UNCTAD told a September 2025 press conference that seaborne volumes would barely rise in 2025, by 0.5%, after 2.2% growth in 2024, and that shipping carries more than 80% of world merchandise trade [source: UN Geneva newsroom, 2025]. Trade is close to flat before any of this takes effect.
On emissions, the most recent official IMO figures are from 2018: shipping's total greenhouse gases had risen to 1,076 million tonnes of CO2-equivalent from 977 million in 2012, and its share of global anthropogenic emissions to 2.89% from 2.76% [source: IMO, 2020]. Those are the numbers the Fifth GHG Study, whose terms of reference MEPC 84 approved, is meant to update.
What cannot be done responsibly is the multiplication both camps invite: a price per tonne times a volume of trade, converted into a number on a shelf edge. The draft charges only the shortfall against a benchmark; the benchmark tightens on a schedule that stops in 2035 with four years unwritten; and the price after 2030 does not yet exist as a figure. An estimate built on those gaps would be a projection dressed as a measurement.
What to watch
Three dates and one number. The working group meets again in late November with the guidelines and life-cycle items it could not reach in September; MEPC 85 sits from 30 November; and the resumed extraordinary session is pencilled in for 4 December, subject to what MEPC 85 decides [source: IMO, 2026]. The number is two-thirds, of Parties present and voting, whenever a vote comes.
Through all of it the 2023 IMO strategy and its net-zero-by-around-2050 target remain in force, and the technical work has not stopped: the working group met on schedule the week after the October adjournment, and met again this month [source: IMO, 2025]. What is stuck is the price, not the objective. And if the Committee cannot adopt a global instrument, the alternative on present evidence is not an absence of carbon pricing in shipping. It is more versions of the EU's.