Climate scientists have waded into the debate over the International Maritime Organisation’s (IMO) decision to delay the ratification of its crucial Net Zero Framework (NZF) by a year.

Delegates at a special meeting of the IMO’s Marine Environment Protection Committee (MEPC) backed a Saudi-led motion to delay the ratification until October 2026. However, climate experts say the decision is a major blow to the climate fight given the scale of the maritime sections role in CO2 emissions.

Prof Alice Larkin, professor of Climate Science and Energy Policy, at the University of Manchester, said: “All sectors must accelerate their mitigation ambitions given how urgently a global energy transition is needed, whilst recognising that building resilience to climate change becomes harder and more expensive the longer climate action stagnates.

“While the maritime sector has a long way to go in realising a rapid sector-wide shift to minimise fossil fuel use, today was a chance to illustrate to the world that it is actually possible for a sector to adopt a mandatory target at a global scale. This delay in its adoption, for one more year, will have a material and inequitable impact on people around the globe.

“With a global carbon budget associated with a 50:50 chance of avoiding 1.5C of warming set to be exhausted in less than 3 years, it is clear how significant and disastrous a 1-year delay in any mitigation effort is for people and the planet.”

Dr Simon Bullock, research fellow at the Tyndall Centre for Climate Change Research, University of Manchester, said the decision had been driven by those nations which were keen to see the continued use of fossil fuels and would create new hurdle for efforts to tackle global warming.

“Yet again, powerful fossil fuel states are successfully blocking global efforts to co-operate on climate change. This is not the result the industry wanted, nor one the world’s people can afford,” he said. “Progressive shipping businesses and nations can still chart a course to a clean shipping future, but Mr Trump’s aggressive, destructive lobbying has their made their job much harder.”

Bob Ward, policy and communications director at the Grantham Research Institute on Climate Change and the Environment at the London School of Economics and Political Science, placed the blame squarely at the feet of US president Donald Trump.

“Action is overdue to tackle greenhouse gas emissions from international shipping,” he explained. “This delay is extremely unhelpful at a time when climate change impacts are increasing and harming lives and livelihoods all over the world. The bullying by the US Government proves that the Trump administration is a threat to the well-being and prosperity of people across the globe.”