IMO adopts net-zero rules, industry divided

BIMCO addressed the question of emissions accounting, particularly during port calls and waiting time. It welcomed changes to the IMO Data Collection System (DCS), which will now incorporate the GHG intensity metrics and update definitions such as “underway” - now defined as the period between full ahead on passage and end of sea passage.

The GHG rules require each ship to update its Ship Energy Efficiency Management Plan (SEEMP Part II) to include GFI reporting elements, verified prior to the first reporting period. GHG emissions factors and sustainability declarations must be certified by an approved Sustainable Fuel Certification Scheme (SFCS). By 1 March 2027, IMO will publish an initial list of recognised SFCSs.

According to DNV, “the regulations are designed in this manner so that most ships will use sufficient low-GHG emission fuels to reach the Base target and then buy Tier 1 RUs. Alternatively, they can buy SUs to cover the Tier 2 compliance deficit and then acquire Tier 1 RUs.”

Revenue generated from RU purchases will be managed by the IMO Net-Zero Fund and redistributed as rewards to ships using zero or near-zero emissions energy sources. However, the specifics of the reward mechanism remain under development.

Alongside the Net-Zero Framework, MEPC 83 also agreed to new annual reduction factors for the Carbon Intensity Indicator (CII), with Z-factors rising to 21.5% by 2030. Phase two of the short-term GHG measure review will begin in January 2026.

On the regulatory front, MEPC 83 adopted amendments to the NOx Technical Code to allow for multiple engine operational profiles and set guidelines for the re-certification of substantially modified engines. These changes will take effect from 2026 and 2027.

The North-East Atlantic was approved as a new Emission Control Area (ECA) for sulphur oxides (SOx), particulate matter (PM), and nitrogen oxides (NOx). The region covers the Exclusive Economic Zones and territorial seas of Greenland, Iceland, the Faroe Islands, Ireland, the United Kingdom, France, Spain, and Portugal. The sulphur cap will apply from 2028, and Tier III NOx standards will follow for newbuilds contracted after 1 January 2027.

MEPC 83 also progressed ballast water regulations, confirming that “challenging water quality” (CWQ) testing will become mandatory during type approval for all ballast water management systems. A Correspondence Group will refine amendments ahead of MEPC 84 in spring 2026. BIMCO, which has long supported more stringent validation, welcomed the direction of travel.

Guidelines were also adopted for the measurement of non-CO2 GHG emissions, specifically methane and nitrous oxide, and a Correspondence Group has been tasked with developing a broader verification framework. A parallel workstream was launched on onboard carbon capture systems (OCCS), targeting full regulatory development by 2028.

Beyond climate matters, the Committee approved interim guidance permitting oil tankers to carry biofuel blends containing up to 30%. It also endorsed the 2025 Action Plan on marine plastic litter and agreed in principle to designate two Particularly Sensitive Sea Areas off the coast of Peru.

In closing remarks, Mr Dominguez acknowledged the divergence of views but defended the Committee’s approach: “This is not about winners and losers. This is about compromise, collaboration and cohesion.”