Approved at the IMO in April 2025, a global carbon price for shipping had its adoption adjourned by a 57 to 49 vote in October 2025, so as of 2026-09-15 it cannot enter into force before 2028-03-01

What is happening?

International shipping has no binding global price on its greenhouse gas emissions, and the one that the International Maritime Organization drafted and approved has not been adopted.

The organization set its direction on 2023-07-07, when its Marine Environment Protection Committee adopted the 2023 IMO GHG Strategy. The strategy aims at net-zero emissions from international shipping by or around 2050, with checkpoints against 2008 of at least 20 percent lower by 2030, striving for 30 percent, and at least 70 percent lower by 2040, striving for 80 percent. The strategy is not itself a binding instrument.

The instrument meant to deliver it is the IMO Net-Zero Framework, a new chapter 5 of MARPOL Annex VI that combines a global fuel standard with a global greenhouse gas pricing mechanism, described in commentary as a global carbon price on shipping. It would apply to ocean-going ships above 5,000 gross tonnage, which account for more than 85 percent of CO2 emissions from international shipping. The committee approved the draft at its 83rd session, held 2025-04-07 to 2025-04-11, by 63 votes to 16 with 103 states participating. The plan was to adopt it at an extraordinary session in October 2025 and bring it into force 16 months after adoption.

On 2025-10-10, before that session opened, the heads of three federal departments of the United States issued a joint statement rejecting the framework. As a law firm summary describes it, the statement listed measures under consideration that included investigations of anti-competitive practices, visa restrictions, disadvantages in government contracting, additional port fees and possible sanctions on officials. No opened source connects that statement to how any delegation later voted.

At the extraordinary session, held 2025-10-14 to 2025-10-17, the adoption vote was not taken. Saudi Arabia moved to adjourn adoption for one year, and the motion carried with 57 votes for, 49 against and 21 abstentions, while 8 further delegations did not take part in the vote. After that adjournment the earliest date on which the framework could enter into force became 2028-03-01, at least a year later than the original sequence. The organization has announced that the talks will resume in 2026, and no opened source records an adoption vote as of 2026-09-15.

Whose problem is this?

The committee that has to adopt the amendments is the same forum that approved them in April 2025 and voted to adjourn their adoption in October 2025, and no other institution can adopt them in its place.

Where does this problem end?

The boundary matters here because the instrument was already drafted and approved, and what stalled is the step that turns an approved text into a binding rule.

A reader who favours a price on shipping emissions and a reader who opposes one can both agree on the dates and vote counts set out below.

What is the state now, and what should it be?

Now

What it should be

The target state is on the record in two documents of the organization itself. The 2023 IMO GHG Strategy, adopted on 2023-07-07, aims at net-zero greenhouse gas emissions from international shipping by or around 2050, with checkpoints of at least 20 percent below 2008 by 2030, striving for 30 percent, and at least 70 percent below 2008 by 2040, striving for 80 percent. The approval of April 2025 then set the timetable for the instrument: adoption at an extraordinary session in October 2025 and entry into force 16 months after that.

The strategy carries no binding force of its own, and the timetable set at approval has slipped by at least a year. No opened source names a date by which adoption has to happen.

How big is it?

The magnitudes that opened sources carry are emissions, coverage, prices and jurisdictions rather than a headcount of affected people.

Emissions scale. The Fourth IMO Greenhouse Gas Study put shipping CO2 emissions at 1,056 million tonnes in 2018, equal to 2.89 percent of global anthropogenic CO2 emissions in that year. That is the most recent emissions year carried by any source opened here.

Coverage scale. The framework would apply to ocean-going ships above 5,000 gross tonnage, which the organization states account for more than 85 percent of CO2 emissions from international shipping.

Price and revenue scale. For 2028 to 2030 the approved mechanism requires ships to buy remedial units at USD 100 per tonne of CO2 equivalent for a tier 1 deficit measured against the direct compliance target and USD 380 per tonne for a tier 2 deficit measured against the base target, according to law firm commentary. An environmental organisation estimates that this structure would raise about USD 10 billion to 15 billion a year, and puts the yield of a flat universal levy that was considered and not chosen at USD 40 billion to 60 billion a year. Neither estimate is an IMO figure. The revenue would go to an IMO Net-Zero Fund, which the organization says would reward low-emission ships, support innovation, fund technology transfer and mitigate negative impacts on vulnerable states.

Jurisdictional scale. The organization lists 176 member states and 3 associate members. The small island developing states, whose combined population the UN puts at about 65 million, or less than 1 percent of the world population, are described by the UN as depending on external markets because their resource bases are narrow.

No affected population is derivable, and the reason is structural. The units these sources count are tonnes of CO2, shares of emissions, member states and dollars, and none of them is a count of persons. Converting the 176 member states into a headcount would measure the size of those states rather than the effect of the adjournment. The one group with a population figure, the small island developing states, is exposed in two opposite directions at once, to higher freight costs if the price applies and to slower mitigation if it does not, so no single multiplier turns that figure into a count of people affected by the delay.

Under what conditions does it arise?

1. The target and the instrument sit in different documents. The 2023 strategy that sets the 2050 aim is not binding, so anything binding has to arrive through an amendment to MARPOL Annex VI that the Parties vote to adopt. Until that vote passes, the checkpoints for 2030 and 2040 have no binding mechanism attached to them in any opened source.

2. Approval and adoption are separate decisions. A majority of the states voting approved the draft in April 2025, and that approval did not commit anyone to adopting it in October. At the October session a motion to adjourn was put to a vote first and carried, so the adoption vote itself never took place and the text stayed where it was.

3. Adoption is not the last gate. Under the tacit acceptance procedure described in law firm commentary, an adopted amendment still does not enter into force if, during a period of at least ten months, one third of Parties or Parties holding at least 50 percent of world merchant tonnage object to it. A framework that wins adoption can therefore be stopped a second time. No opened source says whether that threshold has ever been reached for an amendment to MARPOL Annex VI.

4. Costs and benefits fall unevenly across the states that vote. The price would be charged per ship on emissions above the targets, while the benefit is a reduction in a global stock of emissions that no single state captures on its own. A maritime market analyst reports that the state which moved the adjournment regarded the measure as affecting energy producing countries disproportionately and as not taking account of regional differences in readiness for the transition. The small island developing states sit on both sides of the same ledger, as importers that pay freight and as places exposed to the climate change the framework addresses.

5. Every delay of adoption moves the start date by the same amount. Because entry into force follows adoption after a fixed interval of 16 months, a one-year adjournment of adoption pushed the earliest possible start to no earlier than 2028-03-01.

What has been tried?

Two steps were taken in sequence and each worked on its own terms. A strategy was adopted, and a binding instrument to deliver it was drafted and approved by a clear margin. What did not happen is the vote that would have made the instrument binding, and the same committee will take that question up again.

What was found?

Why is it still unsolved?

Coordination failure — adopting the framework needs a winning vote of the Parties at a session and then the absence of a blocking objection for at least ten months, while leaving it unadopted needs neither, so the outcome that requires no further agreement is the one that persists.

The approval of April 2025 showed that a majority of the states voting supported the draft, and it created no obligation on anyone to adopt it. When the extraordinary session met in October, the question put first was whether to vote at all, and a motion to adjourn carried 57 to 49 with 21 abstentions. No opened source describes any step that turns an approved draft into an adopted rule after a set time, so the draft waits for the next session that chooses to vote on it.

The second part is that adoption, when it comes, opens a second gate rather than closing the question. Under tacit acceptance an adopted amendment is stopped if one third of Parties object, or if the objecting Parties hold at least half of world merchant tonnage. That second threshold does not count states equally, so a smaller group of states with large registered fleets can stop entry into force even after a vote to adopt has been won. No opened source says whether the threshold has ever been reached for this annex, which means the size of the second gate is known only as a rule and not as a record.

The third part is that the positions on the record point in different directions and no source connects them to votes. The United States government issued a rejection of the framework before the session, and a market analyst attributes to the state that moved the adjournment a concern about the effect on energy producing countries. No opened source records how any delegation voted. A coordination problem of this shape does not need a single opponent to hold; it needs only that the delegations willing to adopt at a given session be outnumbered by those willing to wait, and in October 2025 they were.

What observation would mean it is solved?

Candidates — (a) the Marine Environment Protection Committee adopts the amendments to MARPOL Annex VI that establish the Net-Zero Framework (b) the amendments pass the tacit acceptance period without objections from one third of Parties or from Parties holding 50 percent of world merchant tonnage, and enter into force (c) measured greenhouse gas emissions from international shipping move toward the 2030 checkpoint of at least 20 percent below 2008.

(a) alone is weaker than it looks. Adoption is followed by a second gate at which the amendments can still be stopped, and a text adopted after further negotiation may carry different price levels or scope from the draft approved in April 2025, so adoption alone does not show that the approved instrument has survived.

(b) is the institutional endpoint but still counts paper. A framework in force sets prices and fuel intensity targets, and the targets are reviewed every five years, so what actually changes on ships depends on the levels set at each review rather than on entry into force as an event.

(c) alone can move for other reasons. Shipping emissions respond to trade volumes, fuel prices and regional schemes as well as to any global rule, and the most recent emissions year in the opened sources is 2018. The three have to be read together: (a) tests whether the committee can decide, (b) tests whether that decision survives the objection thresholds, and (c) tests whether emissions follow.

What is it connected to?

Fills with researchregional emissions trading schemes applied to shipping, other IMO climate measures such as the EEXI and CII efficiency rules, climate finance for small island developing states, and consensus and voting problems in other treaty bodies addressing global emissions. Relation type and evidence grade were not established in this round.

What these sources do not say

• How each delegation voted. Opened sources give the counts of 57, 49 and 21 and name the state that moved the adjournment. No opened source carries a roll call linking any other delegation to its vote.
• Whether the joint statement of 2025-10-10 changed any vote. Because no roll call is among the opened sources, the order of the dates cannot be read as cause and effect.
• The reasons of the state that moved the adjournment, in its own words. The only account of its position opened here is a market analyst characterisation. No statement by that delegation is among the opened sources, and the official IMO meeting summary page that was sought returned a server error.
• The text of the joint statement of 2025-10-10. Its content is carried here as described in law firm commentary. The statement itself was not among the opened sources, so its exact terms and any reasons it gives beyond rejection are not carried.
• The number of abstentions at the approval vote. Opened sources give 63 for, 16 against and 103 participating. The 24 states that voted neither way are a subtraction, not a published figure.
• What the one-year delay costs. There is an estimate of what the pricing mechanism would raise each year, and no opened source estimates the cost of the delay itself in money or in emissions.
• How the IMO Net-Zero Fund would be divided. The organization lists four uses and no opened source gives the share for any of them, including the share reaching small island developing states and least developed countries.
• Whether the tacit acceptance thresholds have ever blocked an amendment to MARPOL Annex VI. The procedure is described as a general rule, and no opened source gives a precedent either way.
• What the session scheduled for 2026 is expected to decide. No opened source assesses the likelihood of adoption at that session.
• Emissions after 2018. The most recent shipping emissions year carried by any opened source is 2018.

See the evidence

Few primary IMO documents were read beyond public pages, and none of the committee reports was read. Five IMO pages were opened directly — the release on the Fourth Greenhouse Gas Study, the press briefing on the 2023 strategy, the press briefing on the April 2025 approval, the frequently asked questions on the framework and the briefing announcing that talks resume in 2026 — and between them they supply the emissions figure, the strategy targets, the approval, the scope of ships above 5,000 gross tonnage, the 85 percent share, the 16-month sequence and the uses of the fund. The official membership page and a UN page on small island developing states were also opened, and neither carries an update date for its figure. Everything else comes from secondary accounts: law firm commentary for the joint statement of 2025-10-10, the tacit acceptance thresholds and the remedial unit prices; an environmental organisation fact sheet for the revenue estimates; industry association and trade press accounts for the vote counts; and a market analyst for the stated position of the state that moved the adjournment. Where sources overlap they agree: the adjournment counts of 57, 49 and 21 appear identically in three opened accounts, and the earliest entry into force of 2028-03-01 appears in two and is consistent with the 16-month interval on the IMO page. Where a figure is derived rather than published, it is marked, as with the 24 states that voted neither way at the April 2025 approval. Where a source could not be opened the gap is left visible rather than filled, so the two rows above carry no URL. This is a Path A output, a research-based definition, so observation_refs is empty and provenance_mode: press-derived.

People affected

Estimated range Not derivable

The reason and what is missing are listed under “What is missing” below