Progress by the IMO on Marine Environment Protection

In what was billed as key meeting regarding global shipping, the IMO’s Marine Environment Protection Committee met between 7 and 11 April 2025 at IMO HQ in London.

The headline outcome is agreement by the Committee that proposed amendments to MARPOL Annex VI can be circulated, with a view to formal adoption at an Extraordinary Session to be held between 14 and 17 October 2025.

These proposed amendments to MARPOL contain a series of measures designed to incentivise the reduction of Green House Gas (GHG) emissions from shipping. Under the proposed amendments, all ships over 5000 Gross Tonnes will have to report to their Flag, and to the IMO, their annual energy usage, specifying the GHG production intensity of all fuels, and from which compliance will be assessed against each ship’s target GHG emissions. Ships which produce too much GHG, when measured on what is called a ‘well to wake’ basis, will have to pay to purchase GHG ‘remedial units’.

As well as Flag states ensuring any new MARPOL rules are followed, and associated GHG pricing payments are made, any Port State Control inspection can verify the appropriate Statements of Compliance are held onboard. 

The agenda was not confined to GHG emissions. 

Further protection of the marine environment was secured through the approval of a new Emissions Control Area in the North East Atlantic, expected to be formally adopted in to the MARPOL Convention in October 2025. 

An MEPC Circular was approved containing interim guidance on the carriage of blends of biofuels and MARPOL Annex I cargoes by conventional bunker ships, and an MEPC Circular was approved detailing guidance on in-water cleaning of ships' biofouling.

Amendments to the 2023 Guidelines for the development of the Inventory of Hazardous Materials were also approved, as were amendments to the NOx technical code regarding ships with multiple engine configurations and also certification of engines which have been subject to substantial modification.

A more comprehensive report of the Committee’s decisions, along with an explainer regarding the proposed MARPOL Annex VI amendments to reduce GHG emissions from shipping, will be published in our Institute’s monthly magazine, Seaways.