Divisions Emerge at IMO as US Challenges Global Carbon Tax Proposal
Divisions over how to decarbonise global shipping came into sharp focus at the latest meeting of the International Maritime Organization, as a United States-led coalition pushed back against proposals for a global carbon tax while member states sought to rebuild consensus on emissions reductions.
According to a statement from the U.S. Department of State, American diplomats, alongside partners including Saudi Arabia, Liberia, Panama and Argentina, successfully pressed for negotiations to consider alternative approaches to the proposed Net-Zero Framework, which had included a global carbon pricing mechanism for the shipping sector. The U.S. argued that such a measure would impose undue costs on consumers and industry, positioning its intervention as part of a broader effort to protect domestic economic interests.
The discussions took place during the 84th session of the Marine Environment Protection Committee, held in London, where nearly 100 delegations debated so-called “mid-term measures” to address greenhouse gas emissions from international shipping. While the U.S. characterised the outcome as a collapse in support for the original proposal, the IMO signalled instead that negotiations remain ongoing, with member states agreeing to establish an intersessional working group to refine and reconcile competing approaches.
International Maritime Organization Secretary-General Arsenio Dominguez acknowledged that progress had been uneven but said the process was “back on track”, urging countries to rebuild trust and continue technical work ahead of the next round of talks scheduled for later in 2026. The committee is expected to reconvene for further discussions in the lead-up to its 85th session, with additional meetings planned to narrow differences and develop a consensus framework.
Beyond the debate over carbon pricing, the session produced a range of environmental measures and policy developments. Member states adopted a new Emission Control Area covering the North-East Atlantic, which will introduce stricter limits on sulphur oxides, nitrogen oxides and particulate matter from ships operating in waters extending up to 200 nautical miles from several European coastlines. The measures are due to enter into force in 2027, with full implementation expected in 2028, and are aimed at improving air quality and reducing health risks associated with shipping emissions.
The committee also adopted a revised strategy and action plan to tackle marine plastic litter from ships, reaffirming its goal of eliminating plastic discharges into the ocean by 2030. Additional workstreams were advanced on issues including ballast water management, underwater radiated noise and the development of new regulations governing the transport of plastic pellets at sea.
Concerns about maritime safety and environmental risk were also raised during the session, with the committee adopting a resolution condemning attacks on commercial vessels in the Strait of Hormuz and warning of the potential for large-scale marine pollution in the region.
The outcome of the meeting underscores the complexity of aligning global climate ambitions with economic and political priorities in a sector responsible for a significant share of international trade. While disagreements over carbon pricing remain unresolved, the decision to continue negotiations reflects a shared recognition among member states of the need to address shipping emissions, even as the pathway to doing so remains contested.
