Greenhouse gas emissions from shipping could be halved by 2030 without damaging trade, new research has found, as countries prepare to meet to discuss a potential new tax on carbon produced by ships. Emissions from maritime transportation amount to about 3% of global greenhouse gas emissions, and there are few alternatives to the cheap, heavy and dirty diesel oil used by ships. But the sector has been slow to take up emissions-cutting technologies, and an increasing number of countries want to see a tax on shipping to encourage shipowners to invest in emissions reduction and fund the rescue of countries stricken by climate disaster. The International Maritime Organization, the UN division that governs global shipping, will meet in London today for a fortnight of talks on decarbonising and the potential for a new levy of up to $100 (£78) a tonne of carbon produced by ships. A shipping levy was discussed by nearly 40 world leaders and the heads of global financial institutions last week in Paris. The summit for a new global financing pact, hosted by French president Emmanuel Macron, heard arguments from developed and developing countries in favour of a tax, the revenues of which would flow to the “loss and damage” fund, to help countries suffering the ravages of extreme weather. World Bank estimates show that a carbon tax on shipping could raise as much as $50bn to $60bn a year. Japan, the world’s second largest ship-owning nation, has called for a carbon tax of $56 a tonne of carbon from 2025. But the US is in a difficult position, as president Joe Biden could face stiff resistance to any plans from a Republican-controlled Congress. Janet Yellen, the treasury secretary, signalled a cautious welcome to the proposal at the Paris conference, and John Kerry said he was personally open to such ideas but this was not the official position of the administration. Yellen said: “We’re very focused on the need to raise substantial resources to address climate change and poverty reduction and other global challenges. So we’re very open to innovative approaches. I think it is a very constructive suggestion and would agree with President Macron’s description of the logic of why it would be appropriate, and it’s something that the US will look at.” Kerry said: “I support some kind of revenue raising on a broad basis, but this is not administration policy. I personally have supported pricing carbon, but I’m not advocating a tax or a fee or anything at this point. Certainly the administration is not, but we have to find a way to find more concessionary funding.” Eamon Ryan, the environment minister of Ireland, who acts as the EU’s lead negotiator on loss and damage, said the IMO discussions were finely balanced. “It’s 50:50, it’s not certain that it will be agreed,” he said. He urged all countries at the 175-member IMO to take the first steps towards a tax. “We need to show real commitment on addressing the climate crisis, and these mechanisms would give the developing world confidence that it’s no longer just time for talking, it’s time to act.” Ryan would also like to see aviation taxed for the loss and damage fund. “The great advantage there is on equity – it is the wealthier people who fly,” he said. “One euro on a plane ticket would give us €5bn a year. That’s not a small contribution to the effort we need to make.” As countries prepare for the IMO meetings, which will take place in London from Monday 26 June to 7 July, research published on Monday by the consultancy CE Delft found that CO2 from shipping could be cut by between a third and a half this decade by using already available techniques and embarking on innovative technology such as hydrogen. There are ways of using oil-powered ships more efficiently, including better maintenance of engines, cutting speeds slightly or optimising speeds to the sea conditions. Ships can be fitted with modern forms of sails or “wind-assist” technologies that take some of the strain from engines when the wind is strong. If these were used, and another 5-10% of shipping were to begin to use experimental fuels such as hydrogen, biofuels or forms of electrification with solar batteries, then emissions from fuel use could be cut by between 36% and 47% within the next decade, compared with 2008 levels. Starting to use these methods now will save money in the longer term. University College London has estimated that every year of delay in decarbonising this decade will cost the shipping industry an additional $100bn to reach net zero by mid-century. Campaigners said it was important that the research had found cutting emissions would not have an impact on global trade, as previously countries including Argentina, China, India, Brazil, Ecuador and Saudi Arabia had cited damage to trade as a reason for opposing attempts to regulate carbon within the IMO.