What Would IMO Maritime Climate Plan Mean for Shipping?

The International Maritime Organization (IMO) has laid the groundwork for a potentially transformative climate framework that aims to impose legally-binding greenhouse gas (GHG) limits across the maritime industry.

It marks the first time a whole industry sector could be subjected to mandatory global emissions pricing.

Recent developments at the Marine Environment Protection Committee’s 83rd session (MEPC 83) reveal a complex landscape for the US maritime industry. While the framework offers numerous opportunities, it also presents significant challenges, as industry leaders prepare to navigate an evolving regulatory environment.

However, President Donald Trump stands firm against these changes, stating that the US "will not accept any international environmental agreement that unduly or unfairly burdens the US or harms the interests of the American people".

The IMO’s net-zero vision

The framework proposes amendments to MARPOL Annex VI, introducing a new chapter that targets net-zero emissions from international shipping by or around 2050. This aligns tightly with the organisation’s 2023 GHG Strategy, which prioritises zero and near-zero GHG fuels and incorporates advanced technologies and cleaner energy.

“The approval of draft amendments to MARPOL Annex VI mandating the IMO net-zero framework represents another significant step in our collective efforts to combat climate change, to modernise shipping and demonstrates that IMO delivers on its commitments,” said Arsenio Dominguez, IMO Secretary-General, at the meeting's close.

“Now, it is important to continue working together, engaging in dialogue and listening to one another, if we are to create the conditions for successful adoption."

The framework introduces two principal measures:

• A global fuel standard that progressively reduces a ship’s annual GHG fuel intensity, assessed on a well-to-wake basis.
• A global economic measure that implements a pricing system where ships exceeding GHG thresholds must purchase remedial units, while low-emission vessels are incentivised financially.

These rules aim to cover vessels of more than 5,000 gross tonnage, addressing 85% of CO₂ emissions from global shipping. Should the proposal secure adoption by October 2025, the requirements would become effective in 2027.

Economic implications for the US

The IMO framework ambitions include an innovative Net-Zero Fund, designated to reward low-emission ships and propel investment into clean technologies and infrastructure. The goal is also to support fair transitions in developing economies.

However, this has been met with opposition from the US government. President Trump branded the initiative as “effectively a global carbon tax on Americans levied by an unaccountable UN Organisation". 

A US Department of State statement echoed this sentiment, criticising the proposal as an economic benefit to China, necessitating the use of costly fuels not yet globally accessible.

Furthermore, it objects that the standards would prevent using existing proven technologies, such as liquified natural gas (LNG) and biofuels, where the US leads in lower emission options.

According to the administration, fees imposed for non-compliance with fuel standards could increase transportation costs, impacting American consumers financially. In response to these concerns, the Trump Administration categorically rejects the IMO's draft framework.

Path to Adoption

The outlined roadmap details a clear timeline:

• October 2025: Anticipated adoption at an exceptional MEPC session.
• Spring 2026: Detailed implementation guidelines are expected to gain approval.
• 2027: Framework comes into effect, 16 months post-adoption.

For US ports, ship operators and logistics providers, the period leading up to 2027 becomes crucial for evaluating compliance strategies, exploring alternative fuels and accounting for potential cost implications.

Maritime environmental measures

The MEPC 83 session also progressed several ecological measures beyond emissions. These include a 2025 Action Plan tackling marine plastic litter and a potential biofouling management framework to mitigate invasive species.

Additionally, discussions about new Emission Control Areas advance the agenda for broader environmental safeguarding.

The IMO's net-zero framework has the potential to reshape the maritime industry, merging stringent emission controls with market-driven incentives. However, it represents a challenge for the US to balance international decarbonisation targets with domestic economic competitiveness.

As the October 2025 session draws near, the onus is on US operators to determine whether they will align with emerging sustainability protocols or advocate for alternative solutions and exemptions.