Five months after blocking the adoption of a global carbon pricing mechanism in maritime transport, the United States has once again positioned itself at the center of the political confrontation within the International Maritime Organization (IMO). As the celebration of the Marine Environment Protection Committee, MEPC 84, scheduled from October 14 to 17 approaches, the options for closing an international agreement on the decarbonization of the sector are becoming complicated again.
Washington's offensive comes after the failure recorded in October 2025, when the IMO was to ratify a principle agreement reached months earlier, in April, during MEPC 83. That understanding had advanced with the support of 63.8% of the attending and voting States, against 16 votes opposed, and was set to become the basis for the first global system of economic control of greenhouse gas emissions applied to a complete sector.
However, the ratification did not come to pass. The administration of President Donald Trump then launched a campaign of diplomatic and political pressure that ultimately altered the balance achieved in the spring of 2025. The result was the postponement of the decision for a year, in a context of threats of retaliation and a frontal discourse against any formula that implied an additional cost for CO2 emissions.
At the center of the disagreement is the so-called Net-Zero Framework (NZF), the framework designed at the IMO to guide the global fleet towards climate neutrality by 2050. The proposal combines two elements: on one hand, an economic contribution linked to emissions; on the other, a carbon intensity standard for fuels. With this architecture, the organization seeks to introduce an economic signal that increases the cost of fossil fuels and, at the same time, set a technical path for gradual replacement by lower climate footprint alternatives.
The revenues generated through this scheme should fund an international fund under the umbrella of the IMO. This instrument would aim to finance the energy transition of maritime transport, facilitate the deployment of alternative fuels and assist developing countries, especially small island states, which are among the most exposed to the effects of climate change.
The United States has now reiterated that it will not accept any system that includes a financial penalty, a carbon fee, or a multilateral fund of this nature. In a communication sent to representatives of the IMO, the U.S. administration has positioned the abandonment of the NZF as the only possible way out. Therefore, Washington's position is not limited to discussing the technical design of the mechanism, but questions the very core of the approach negotiated so far.
The political line had already been exposed in August 2025 in a statement signed by Secretary of State, Marco Rubio, along with the heads of Commerce, Energy, and Transport, Howard Lutnick, Chris Wright, and Sean Duffy. In that text, the U.S. administration warned that it would not accept measures that raised costs for its citizens, for energy suppliers, for shipping companies, their customers, or tourism. It also opened the door to retaliation if the initiative proceeded.
Rubio has now reinforced that message by warning that if such regulation is raised again at the IMO, the resistance of the United States and its allies will be "stronger than ever." The formulation confirms that the discussion at MEPC 84 will not solely revolve around decarbonization but also the scope of international regulatory intervention over energy markets and maritime operations.
The U.S. strategy advocates an "all energy" approach, where conventional and alternative fuels compete without normative intervention directing the market towards specific options. In this framework, Washington maintains that all possibilities must be kept open, from oil to liquefied natural gas (LNG), including biofuels and new technologies. According to this approach, it is up to the market to decide which solutions are viable in terms of cost, availability, and scale.
This approach is accompanied by a direct criticism of binding targets for fully decarbonized fuels. For the U.S. administration, setting such standards could indirectly benefit China by forcing the use of expensive fuels that are not yet available on a global scale, while limiting the use of technologies already deployed in the global fleet.
Washington's position finds support among several hydrocarbon-producing countries. In a contribution submitted to MEPC 84, Algeria, Bahrain, Iraq, Kuwait, Russia, Saudi Arabia, Somalia, and the United Arab Emirates argue that it is unrealistic to muster the necessary support for a climate agreement that guarantees carbon neutrality in maritime transport by 2050. By doing so, they strengthen the bloc against global carbon pricing and favor a technologically neutral approach.
Positioned between both stances are some of the world's leading flag registries, such as Panama and Liberia. Their proposal aims for an alternative regulation that, in practice, would leave diesel and LNG as the dominant fuels, reducing regulatory pressure on other less commercially implanted decarbonization routes currently.
The U.S. offensive also extends to existing regional regulations. Washington has called for a gradual withdrawal from duplicated climate frameworks, including the European emissions trading system, the EU ETS, applied to maritime transport. Although the European system does not function as a fixed carbon fee, it does set an emissions cap and requires the purchase of tradable rights in the market.
The U.S. administration believes that the coexistence of regional and global instruments would create regulatory overlaps. In contrast, the European Union maintains that it will continue applying its carbon market to maritime transport as long as the IMO does not approve an effective international regulation. This point remains one of the main lines of friction between Brussels and Washington.
In this context, France has called for greater European coordination ahead of upcoming negotiations. The French Minister of Transport, Philippe Tabarot, recently indicated that he is in contact with several European counterparts to act jointly within the IMO and try to sustain the decarbonization project for the sector. Paris thus insists on the need to preserve an international framework that avoids regulatory fragmentation and allows maritime transport to have a common roadmap.
The MEPC 84 meeting presents itself, therefore, as a new high-risk appointment for the climate governance of maritime transport. On one side are oil-producing states and countries that reject an international carbon price and demand technological neutrality. On the other, remain the supporters of a global regulation with economic instruments and defined objectives to guide the energy transition of the global fleet. Between both blocs, the IMO faces negotiations where not only the pace of decarbonization is decided but also the model of regulation that will govern maritime trade in the coming decades.