IMO MEPC 83: What’s on the agenda?

The MEPC meeting will be preceded by the 19th meeting of the Intersessional Working Group on Reduction of Greenhouse Gas Emissions from Ships (ISWG-GHG 19), from 31 March – 1 April and the first meeting of the Intersessional Working Group on Air Pollution and Energy Efficiency (ISWG-APEE 1), from 2 to 4 April.

The Marine Environment Protection Committee (MEPC) addresses environmental issues under IMO’s remit. This includes the control and prevention of ship-source pollution covered by the MARPOL treaty, including oil, chemicals carried in bulk, sewage, garbage and emissions from ships, including air pollutants and greenhouse gas emissions. Other matters covered include ballast water management, anti-fouling systems, ship recycling, pollution preparedness and response, and identification of special areas and particularly sensitive sea areas.

1. Tackling climate change – Reduction of GHG emissions from ships 

The 2023 IMO GHG Strategy outlines a set of “mid-term measures” aimed at reducing greenhouse gas emissions from international shipping in line with the reduction targets set out in the Strategy. These measures should consist of: 

• a technical element: a goal-based marine fuel standard designed to gradually lower the GHG intensity of marine fuels; and 
• an economic element: a pricing mechanism for maritime GHG emissions. 

The Committee is expected to finalize draft legal text for these measures, referred to as the “IMO Net-Zero Framework”. This will consist of amendments to Annex VI of the MARPOL Convention, expected to be approved by MEPC 83 for circulation immediately after the meeting, with a view to adoption by an extra-ordinary session of MEPC in October 2025.  

Additionally, the Committee will be invited to approve the provisional agenda for the forthcoming Extraordinary Session (MEPC/ES.2), scheduled for October 2025 which is expected to formally adopt a revised MARPOL Annex VI, incorporating the IMO Net-Zero Framework. Following adoption, depending on the decision of the Committee, the measures could enter into force 16 months later, under the “tacit acceptance” procedure.  

2. Review of the short-term measure to reduce GHG emissions 

IMO’s short-term GHG reduction measures (EEXI, CII rating), developed to improve ship energy efficiency and reduce carbon intensity by at least 40% compared to 2008 levels by 2030, entered into force on 1 January 2023.  

The review process started in 2023 and included a data gathering and analysis stage, and a convention and guidelines review stage. The Committee is expected to finalize phase 1 of the review of relevant provisions of MARPOL Annex VI and associated mandatory guidelines, and develop a work plan for Phase 2 of the review, starting on 1 January 2026. 

3. Energy efficiency of ships

The Committee is expected to:  

• finalize and adopt draft guidelines for test-bed and onboard measurements of methane (CH₄) and/or nitrous oxide (N₂O) emissions from marine diesel engines; 
• approve a work plan on the development of a regulatory framework for the use of onboard carbon capture and storage (OCCS); and 
• re-establish the Correspondence Group to further develop the framework for the measurement and verification of actual methane and nitrous oxide emission factors and fuel slippage values and develop a regulatory framework for the use of OCCS.  

4. Action Plan to address marine plastic litter from ships 

The Committee is expected to adopt the draft 2025 Action Plan to Address Marine Plastic Litter from Ships (2025 Action Plan) agreed by Sub-Committee on Pollution Prevention and Response (PPR 12), and approve updated groupings of short-, mid- and long-term actions under this plan. 

The 2025 Action Plan is expected to be combined with the Strategy to Address Marine Plastic Litter from Ships in a single resolution at a later date, after the Strategy has been reviewed and updated by the PPR Sub-Committee. 

With regard to the carriage of plastic pellets in freight containers by sea, the Committee is expected to note that PPR 12 included a dedicated action for the development of mandatory measures to reduce the environmental risks of plastic pellets transported by sea in freight containers in the above 2025 Action Plan, as a first step towards the development of mandatory regulations to address the issue.  

5. Identification and protection of Special Areas, Emissions Control Areas and Particularly Sensitive Sea Areas

The Committee will consider proposals to designate the North-East Atlantic Ocean as an Emissions Control Area for SO_X, PM and NO_X; and PSSAs in the sea areas “Reserva Nacional Dorsal de Nasca” (Nasca Ridge National Reserve) and “Reserva Nacional Mar Tropical de Grau” (Grau Tropical Sea National Reserve) in South America’s Pacific Ocean. 

6. Addressing harmful aquatic organisms in ballast water 

The Committee will continue its ongoing review of the Ballast Water Management (BWM) Convention at MEPC 83. This will include stocktaking of the progress made and consideration of the way forward with regard to the overall plan for completion of the review, with some high-level decisions needed to facilitate the achievement of the review targets. The Committee is expected to re-establish the Correspondence Group working on this issue to finalize draft amendments to mandatory provisions (regulations and appendices in the Annex to the Convention, and BWMS Code), for submission to MEPC 84 for approval and adoption by MEPC 85. The revision of existing and development of new guidelines are expected to be completed ahead of the amendments’ entry into force.   

7. Air pollution prevention 

The Committee is expected to consider the outcome of PPR 12 regarding Exhaust Gas Cleaning Systems (EGCS), NO_x emissions and Black Carbon emissions. 

Exhaust Gas Cleaning Systems (scrubbers) 

The Committee is expected to note an update from the PPR Sub-Committee on regulating the discharge from EGCS or “scrubbers”. Interested Member States and international organizations were invited to submit new proposals on regulatory measures addressing the matter to PPR 13 (early 2026). 

MEPC 83 is expected to request the re-establishment of the GESAMP Task Team on EGCS to develop a standard methodology for the development of data sets and calculation of emission factors for use in the environmental risk assessment of the discharge water from EGCS, with a view to reporting its findings to PPR 13. 

Black Carbon emissions 

The Committee is expected to note the ongoing work on the concept of “polar fuels” (fuels that are most suitable for use in the Arctic to minimize environmental impact) and extend the target completion year for this output to 2027, to allow additional time to further develop the concept. 

Nitrogen Oxide (NOx) emissions 

MEPC 83 is expected to adopt an MEPC resolution on 2025 Guidelines on Selective Catalytic Reduction (SCR) Systems. SCR systems are active emission control technology systems used to reduce NO_x emissions. 

8. Amendments to NOx Technical Code 

The Committee is expected to adopt amendments to the NOx Technical Code 2008 concerning the use of multiple engine operational profiles for a marine diesel engine, including clarifying engine test cycles and improving the recertification of existing engines onboard a ship. The amendments will allow optimizing a ship’s fuel consumption depending on its operational profile, hence improving energy efficiency, whilst ensuring compliance with NOx emission requirements. 

9. Pollution prevention and response 

The Committee is expected to: 

• approve Interim guidance on the carriage of blends of biofuels and MARPOL Annex I cargoes by conventional bunker ships; 
• approve Guidance on in-water cleaning of ships’ biofouling; and 
• adopt amendments to the 2023 Guidelines for the development of the Inventory of Hazardous Materials clarifying the relevant threshold in respect to cybutryne when samples are taken directly from the hull or from wet paint containers.  

10. Proposals for new outputs 

MEPC 83 will consider the following proposals for new outputs: 

• Assessment of the implementation of the Hong Kong Convention through an experience building phase and development of clarifications and amendments to the Convention; 
• Development of a legally binding framework for the control and management of ships’ biofouling to minimize the transfer of invasive aquatic species; 
• Review and amend, as appropriate, the NOX Technical Code 2008 to provide a means for certification of engines using non-carbon-containing fuel or mixtures of carbon-containing and non-carbon-containing fuels); and 
• Development of guidelines for the management of ammonia effluent generated by ships using ammonia as fuel