Washington Moves to Weaken IMO Climate Plan with Last-Minute Rule Change

By Jack Wittels (Bloomberg) — The US made a proposal at talks held by the global shipping regulator to introduce another step in adopting a charge on vessel emissions if countries vote for it this week, as Washington continues to oppose the planned new rules.

Nations are at an International Maritime Organization meeting in London to decide on landmark regulations to make vessels start paying for their greenhouse gas emissions. The Trump administration is strongly against the move, which it has labeled a “global carbon tax” on Americans, and has said it would consider wide-ranging measures against those who backed them.

On Wednesday, the US proposed changing acceptance rules, according to a document provided by the IMO at the meeting.

Usually, under shipping’s main treaty on pollution, new regulations are considered accepted unless a third of countries — or half the world’s merchant fleet — declare they object, a process known as “tacit acceptance.” But the US has now proposed that the IMO require “explicit acceptance” — effectively needing nations to officially opt in after the vote, according to a document.

The proposal is another example of the US putting pressure on the planned rules, because it would add a further hurdle for them coming into force. Washington has already threatened to respond with measures such as port levies, visa restrictions and tariffs.

The IMO said a drafting group was instructed to take into account proposals made in the plenary, and that any changes will be clearer once its report is received.

© 2025 Bloomberg L.P.

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