US President Donald Trump has again taken aim at the International Maritime Organization’s Net-Zero Framework (NZF), using his address to the UN General Assembly to highlight his administration’s efforts to block the shipping decarbonisation measures last year.

Speaking at the 81st session of the UN General Assembly in New York on September 22, Trump singled out the IMO as he criticised what he sees as attempts by international organisations to impose global taxes.

“Last year, my administration had to intervene to stop a little-known U.N. agency called the International Maritime Organization from secretly establishing the first-ever global carbon tax,” Trump said.

He described the measure as a “very expensive tax” and claimed it could increase international shipping costs by between 10% and 20%, or potentially more.

“There is no global government — and while I am President, there will be no global taxes,” Trump said.

The White House also highlighted the remarks in its official summary of the president’s UN address.

Trump’s comments come just over two months before IMO member states are due to return to negotiations over the future of the NZF and mark another direct intervention by the US president in the debate over global shipping decarbonisation.

The IMO Net-Zero Framework, however, is not formally defined as a “global carbon tax”. It is a package of mandatory measures developed to implement the 2023 IMO GHG Strategy and combines a global marine fuel standard with a GHG emissions pricing mechanism.

The Trump administration has repeatedly described the framework as a “global carbon tax”. The term presents the NZF as a single global levy, while the proposed framework is broader and includes both technical and economic measures aimed at reducing the lifecycle GHG intensity of marine fuels.

The US has opposed the framework since negotiations at MEPC 83 in April 2025. Washington subsequently stepped up its campaign against the NZF, warning ahead of its planned adoption in October last year that countries supporting it could face measures including visa restrictions, additional port fees and commercial restrictions.

Trump personally joined the campaign on October 16, 2025, posting on Truth Social the day before the crucial IMO decision. He described the NZF as a “Global Green New Scam Tax on Shipping”, said the US would not accept or comply with it, and urged IMO member states meeting in London to vote against it.

The extraordinary MEPC session subsequently adjourned for one year without formally adopting the framework.

The NZF nevertheless remains under negotiation. IMO member states returned to the issue at ISWG-GHG 22 from September 1 to 4 this year, where delegates discussed possible changes to address concerns raised by member states. While there were signs of willingness to seek compromise, major differences over the future design of the framework remain unresolved.

The next round of talks, ISWG-GHG 23, is scheduled for November 23-27, followed by MEPC 85 from November 30 to December 3. The extraordinary MEPC session adjourned last year is provisionally scheduled to resume on December 4, subject to confirmation by MEPC 85.

Trump’s latest intervention leaves little doubt about the US position as those talks approach. Whether IMO member states can find a compromise capable of securing broader support for the framework will now be a key issue heading into the December meetings.