LIBERIA and Panama, the two biggest flag states by registration, have joined a host of countries in favour of a flat tax on shipping’s greenhouse gas emissions.

This is no surprise; companies from Maersk to Trafigura have long advocated such a measure, as has shipowner group the International Chamber of Shipping. The two countries represent around 800m dwt of shipping capacity, or around a third of the global fleet.

At the International Maritime Organization, however, they represent two votes out of 176 countries.

All the more significant, then, that the Pacific Island bloc of climate progressives have corralled so much support — 45 countries and growing, plus the European Commission — in favour of combining disparate levy plans into one legal text, that could then become a new chapter of Marpol.

Big questions remain, such as what such a levy should cost, and how its vast proceeds should be spent. China, Brazil, the US and other levy holdouts should put aside their objections and instead work together to answer these questions. They have precious little time left to do so.

At the end of the day it doesn’t matter what the number in dollars per tonne of CO2 equivalent is, as long as it applies equally to all. Shipping companies can simply pass on the cost and then concentrate on finding the cheapest way to go green.

An emissions trading scheme such as the EU’s would be subject to volatile carbon credit prices, political chicanery and fiddly calculations. It would also be more complex to implement.

Fudge factors, exceptions and loopholes would create perverse incentives and openings for the sort of shell games shipping is already adept at. This would be a waste of time and money.

It would also paint the industry in a bad light at a time when shipping badly needs new talent to replenish its ranks. Doing right by the planet is catnip to Gen Z. Financiers quite like the idea, too.

A global levy would give floundering green energy companies the certainty of demand they need to scale up production.

Shipping will also need hundreds of millions of tonnes of green fuels, starting from supply of roughly zero today. The implications for high-tech industrial jobs — particularly in left-behind industrial cities and towns — should excite politicians. Dirtier ships will be scrapped sooner, helping shipping markets.

The IMO, led by the tenacious Pacific Islands, has a chance to show global leadership this year. Its carbon levy could act as a blueprint for decarbonising other heavy industries, and in doing so truly change the world for the better.

A levy is the simplest and lowest-cost way to decarbonise shipping. For the sake of the planet and our industry’s future, the IMO should adopt one without delay.