Every day, tens of thousands of massive ships criss-cross the world’s oceans, transporting grain, clothing, electronics, cars, and countless other products. Nearly 90 per cent of global cargo is moved this way. But this vital industry comes with an added cost: international shipping is responsible for three per cent of global greenhouse gas emissions, which are heating the planet.

For years, ship emissions were a complex and often postponed topic in international climate discussions. But that changed in April 2025 when the International Maritime Organization (IMO), the UN body overseeing global shipping regulations, approved a historic plan to make the industry net-zero by around mid-century.

“This demonstrates that multilateralism and the United Nations are still relevant and important in these particular times,” Arsenio Dominguez, IMO’s Secretary-General, told UN News. He reflected on the tense and often emotional negotiations at the Marine Environment Protection Committee’s 83rd session, calling the approval a commitment by IMO and the shipping sector to combat climate change.

The deal, dubbed the IMO Net-Zero Framework, marked the culmination of years of painstaking talks between member States, including small island nations at risk from rising seas and the world’s largest shipping nations.

“I could spend hours just telling you in detail all those great moments working very closely with the delegates of all the member states at IMO in order to get this agreement,” Mr. Dominguez recalled. “That collaborative approach, to see all the member states gathering and rallying each other to get this deal in place, is something that I will always remember.”

Arsenio Dominguez, Secretary-General of the International Maritime Organization (IMO).

A breakthrough years in the making

The 2025 breakthrough did not happen overnight. The IMO’s work to tackle emissions spans more than a decade. In 2011, it rolled out the first mandatory energy efficiency measures for ships. Then, in 2018, member countries agreed on the Initial IMO Strategy on Reduction of GHG Emissions from Ships, marking the first international targets to cut the sector’s climate impact.

Building on that progress, IMO ramped up ambition in 2023 and set clear goals: reduce emissions by at least 20 per cent by 2030 and 70 per cent by 2040, and phase in zero or near-zero emission fuels. The 2025 Net-Zero Framework transforms these plans into binding regulation.

“We’re focusing first on 2030, meeting those goals of reducing emissions by at least 20 per cent, and achieving at least a five per cent uptake of alternative fuels, because it’s going to pave the way for the next set of actions and demonstrate what other mechanisms or measures we need to put in place,” Mr. Dominguez said.

Shipping containers at a port in the Democratic Republic of São Tomé and Príncipe.

The machinery of global commerce

What’s at stake is more than just the environment – it’s the very machinery of global commerce. In 2023, maritime trade volumes soared past 12 billion tonnes of cargo, UN data shows. “Even the chair you are sitting on right now was likely transported by ship,” remarked Mr. Dominguez. “Things move around by ship because it’s the most efficient method of mass transportation. But that comes with responsibility and some drawbacks”.

Although the shipping sector has been ‘slow’ to regulate its climate impact, the 2025 framework is changing that with two key measures: a global fuel standard to reduce greenhouse gas intensity and a pricing mechanism for ships exceeding emission thresholds.

Polluters will need to purchase ‘remedial units’ or offset their excess emissions by investing in the IMO Net-Zero Fund. Ships adopting zero or near-zero emissions technologies can earn surplus credits, creating an incentive to clean up. A shipowner exceeding their emissions limit might buy credits from another ship that has outperformed its targets or contribute to the fund.

Revenues from the fund will be used to reward low-emission ships and help developing countries with capacity building, technology transfer, and access to alternative fuels.

Oversight by member States and IMO will ensure accountability for the new measures. “We work with the member States, particularly small island developing states and least developed countries, to enhance the implementation of IMO instruments,” Mr. Dominguez explained.

Certification, verification, audits, and reporting processes will monitor compliance. “Everything gets reported to the Organization, and from there we take additional measures.”

Balancing climate action and trade

The measures will cover large ocean-going ships that exceed 5,000 gross tonnes, which are responsible for about 85 per cent of industry emissions.

When asked about potential impacts on supply chains and consumer prices, particularly for countries heavily reliant on imports, the IMO chief emphasised that they have carried out a comprehensive impact assessment.

“There is a cost to pay when it comes to decarbonizing and protecting the environment. There has also been a cost to polluting the environment. So, all these rules, of course, are going to have an impact. What we looked at is reducing that impact as much as possible. If there is an impact, the financial measures and pricing mechanisms will support the industry’s transition’’.

Innovation will play a major role, and some promising technologies include ammonia and hydrogen fuels, wind propulsion, solar-assisted shipping, and onboard carbon capture. “Our rules are there to foster innovation and not to limit it,” Mr. Dominguez said, explaining that the Organization is carrying out an initial analysis. “We are rediscovering the existence of wind in the shipping industry, if I may say it like that…We have to be open to everything that’s happening out there. There’s a lot of work going on alternative fuels.”

This transition will also require investment in training and safety measures for seafarers as these alternative fuels are adopted, he warned. “We have to pay paramount importance when it comes to the people.”

A seafarer on board a ship at Felixstowe Port in England.

An industry in transition

The framework sets a strict timeline: industry emissions must drop by at least 20 per cent (striving for 30 per cent) by 2030, by at least 70 per cent (striving for 80 per cent) by 2040, and reach net-zero by around 2050. The first compliance year will be 2028.

“The end goal of the main objective of the strategy is to decarbonize to reach net zero by around 2050. But it doesn’t mean that we’re not doing anything between,” Mr. Dominguez stressed. “This is a progressive approach.”

The IMO has also committed to constant review and refinement. “For us, it’s not just about the next step,” Mr. Dominguez said. “It will be a constant process of analysis, review, and engagement to gather the experience and expertise needed to tweak or provide any additional support that may be required’’.

Beyond emissions

While greenhouse gases dominate the headlines, Mr. Dominguez explained that shipping’s environmental footprint extends beyond CO₂. “There’s so much more that this Organization [does],” he said.

IMO measures address issues like biofouling, which is the accumulation of aquatic organisms like algae and barnacles on the hulls of ships, increasing drag and fuel consumption; underwater noise, which can disturb marine life; and ballast water management, which prevents invasive species from being transported across the globe.

“We always take into account that ships touch many parts of the environment, and we need to protect them,” he added.

The road ahead

When UN News asked about the framework’s adoption at IMO’s extraordinary session in October, Mr. Dominguez stated: “Of course, I’m confident because we just demonstrated that multilateralism is still relevant, that IMO is ready to meet its commitments”.

He explained that the next step will be addressing concerns and developing guidelines for implementing the new measures, including the pricing mechanism.

“That is going to help us meet the very ambitious timeframe that member states are committed to, so that as soon as these amendments enter into force in 2027, we can start demonstrating with tangible results what the shipping industry means when it talks about decarbonization.”

For Mr. Dominguez and many observers, the agreement represents a rare victory for multilateralism – and a new beginning for a critical but long-overlooked sector. “It’s not if we get it right. We are getting it right,” he said. “This is a process, a transition. We’re taking the first steps now that will lead us to the main goal.”