The global regulator for international shipping is expected to agree to completely decarbonise the industry by mid-century to avoid dangerous climate change.
However, whether the sector's transition to end its reliance on fossil fuels will be aligned with keeping rising temperatures under 1.5 degrees is uncertain, a shipping expert says.
The International Maritime Organisation (IMO) Marine Environment Protection Committee (MEPC) is meeting next month with renewed hopes of improving on its current target to halve shipping emissions by 2050.
University College London's shipping and energy specialist Tristan Smith said: "The Pacific have done a great job of getting them [IMO members] to this point where they're able to share that level of political agreement."
The IMO has momentum to agree on full decarbonisation by 2050, but "a lot of the devil is in the details", he said.
"Whether that's defined with an equitable transition or not isn't clear," Smith told RNZ Pacific, as over 170 IMO member states prepare for the MEPC 80 talks in London.
"Whether that's going to involve a 1.5 aligned transition, which would need much to be done this decade and into the 2030s, so quite steep reductions by 2040, that isn't clear.
"Those are the things which are still at risk," he said.
According to the Intergovernmental Panel on Climate Change (IPCC), there needs to be major cuts global greenhouse gas emissions before 2030 to avoid runaway climate change.
The IPCC predicts that global heating to be devastating for Pacific island nations who are at the forefront of climate change impacts.
With global shipping responsible for almost three percent of the world's greenhouse gases, for the industry to be aligned with the 1.5 degrees Paris Agreement threshold, Dr Smith said emissions needed to be reduced by 36 percent by 2030 and 96 percent in 2040.
"Agreeing to zero by 2050 isn't really good enough," he said.
"It's about the steepness of greenhouse gas reductions in the two and a half decades before that point.
"If it doesn't contribute proportionately then other sectors of the economy are going to have to make up for whatever excess shipping has, or we're going to have to agree that we're not going to hit the 1.5 degrees target."
Dr Smith said, in practical terms, it meant the shipping industry needed to increase its energy efficiency by about 40 percent and moving away from fossil fuels.
He said the sector needed to "massively increase the energy efficiency" but the IMO has not regulated efficiency.
"There's lots of inefficiencies at the interface between ships and ports. Ships hurrying up and then waiting at the port, when they could have just been more slowly across the voyage can make a huge difference to the fuel consumption.
That needs to happen alongside having fuel alternatives, he said.
"We need to be getting a bunch of early adopters, vessels using hydrogen-derived fuels that build up the landside investment that learn how we do these on-board ships at minimum cost.
"And then we need to be ready to roll that out that very rapid growth over the 2030s," he said.
Shipping experts believe both; increasing energy efficiency and alternative fuels; are done in parallel then the 1.5 degrees aligned decarbonisation is achievable.
"Several studies show all of that is feasible, but it will only happen if the IMO's regulation, or their outcomes in July are very clear and very high ambition," Dr Smith said.
Putting a price on fossil fuels
A group of Pacific Island nations, including Solomon Islands, Tonga, Kiribati, Tuvalu and led by the Marshall Islands in 2021 submitted a landmark proposal for a fuel levy on ships starting at $US100 for every tonne of carbon emitted from ships, followed by a new fuel standard, which would essentially ban the use of fossil fuels.
Pacific maritime and shipping expert Dr Peter Nuttall works for a research team on transport decarbonisation out of the Marshall Islands.
He said the levy proposal from Pacific nations would generate up to $US60 billion a year in revenue.
He said $100 a tonne would result in "such a small increase in general trade costs, it's relatively insignificant" to the industry.
While it is unlikely a levy would be adopted at the July talks, Smith said the IMO was showing signs of agreeing to one at some point.
However, a date on a levy decision has not been set.
Dr Smith believes the proposal would make it easier to invest in fossil free solutions.
"Basically, you put a price on the fossil fuels use by charging for the greenhouse gas emissions that it creates, and then that closes the gap or makes more competitive alternatives to fossil fuels," he said.
Dr Smith said the levy would gradually get to a price where hydrogen-derived fuel is on par with fossil fuels and the revenues could be used in a "creative way" such as building necessary infrastructure for alternative fuels to improve the industry.
"The other thing you can do with revenues is address the fact that there are some very vulnerable countries that don't have the economic means to do [climate] adaptation," he said.