Shipping’s Climate Moment: A Tax That Could Reshape the High Seas

This Friday, the global shipping sector may have reached an inflection point. In London, the International Maritime Organization (IMO) gathers its member states to vote on what could become the world’s first binding climate deal for commercial maritime transport. At stake is a carbon pricing framework designed to steer a sector responsible for roughly three percent of global greenhouse gas emissions towards net zero by 2050.

For decades, international shipping has remained a notable climate outlier. It burns some of the dirtiest fuels available and has so far evaded the emissions targets applied to other major industries. That could now change. The proposed "Net Zero Framework" would impose an emissions-based levy on large vessels starting from 2027. Ships exceeding 5,000 tons (about 85 percent of the fleet’s total emissions) would pay a tax proportionate to their carbon output. Depending on final details, the price per tonne of CO₂ could rise as high as 380 dollars, with projected revenues between 10 and 15 billion dollars annually. These funds would flow into a climate finance mechanism intended to support the development of clean fuels and provide aid to developing countries affected by climate change.

Figure 1: Composition of global annual carbon emissions (2024). Source: IEA

What makes this development particularly remarkable is the geopolitical backdrop. While Washington has lobbied aggressively against the deal by threatening with sanctions, port restrictions, and even visa bans, the proposal has garnered unexpected support from major economies including China, India, Brazil, and the European Union. Each has its own reasons. For China, alignment with clean tech leadership and maritime influence plays a role. The EU sees value in a uniform global system to avoid the inefficiencies of overlapping regional rules. For India and Brazil, the structuring of the climate fund (which is part of the broader equity discussion within international climate finance) likely played a role in shaping their positions.

Unlike other UN institutions, the IMO does not operate on the basis of consensus or veto power. A qualified majority is sufficient to adopt new rules. This institutional feature explains both the relative optimism surrounding the vote, and the intensity of the American pushback. While any new regulation would formally apply only to those countries that endorse it, the global nature of maritime transport means the effects would ripple far beyond. Vessels that do not comply could face limited port access or financial penalties in participating states.

For Belgium, the stakes are tangible. With one of the largest maritime clusters in Europe centred around the Port of Antwerp-Bruges, a globally coordinated system would help level the competitive playing field. Domestic players like CMB.Tech, who are already investing heavily in ammonia and methanol as low-carbon alternatives, would benefit from clearer market signals and greater investment certainty. On the contrary, fragmented national rules could raise compliance costs and delay the sector's transition.

Whether the deal ultimately passed (likely decided by the time you read this) will shape the future of one of the most essential and least regulated parts of the global economy. And in a world often paralysed by climate gridlock, this would be more than a symbolic win. It would be a rare case of collective ambition charting a course across genuinely international waters.

Curious how the vote went? It’s worth checking the headlines—history may have been written at sea.