Methane emissions from maritime transport have rapidly emerged as a central issue in international climate governance. While shipping has traditionally focused on carbon dioxide (CO₂), growing attention is now directed toward methane (CH₄), particularly because of the increasing use of liquefied natural gas (LNG) as a marine fuel. LNG has often been presented as a transition fuel capable of reducing sulphur oxides, particulate matter and carbon emissions compared with conventional marine fuels. However, methane slip, the release of unburned methane from engines and fuel systems, has raised important questions regarding the true climate performance of LNG-powered shipping.
Methane is a particularly potent greenhouse gas. Over a 20-year period, its warming impact is significantly higher than that of CO₂. As a result, even relatively small methane leaks can substantially reduce or eliminate the climate advantages associated with LNG use in maritime transport. This has pushed methane emissions to the forefront of both global and European maritime regulation.
The International Maritime Organization (IMO), the principal global regulator of shipping, has progressively strengthened its climate agenda. In 2023, the IMO adopted a revised greenhouse gas strategy aiming for net-zero emissions from international shipping close to 2050. The strategy established indicative checkpoints for 2030 and 2040 and confirmed the need for both technical and economic measures to decarbonise the sector. A detailed analysis of the interaction between EU and IMO approaches is provided in the Oxford Institute for Energy Studies paper, “The decarbonisation of maritime transport: navigating between a global and EU approach”.
The IMO’s approach is based on the recognition that shipping is inherently global and that fragmented regional regulation could undermine efficiency and competitiveness. Existing IMO instruments already include several energy-efficiency measures such as the Energy Efficiency Design Index (EEDI), the Carbon Intensity Indicator (CII), and the mandatory Fuel Oil Consumption Data Collection System (DCS).
However, methane regulation within the IMO framework is still evolving. The revised IMO strategy increasingly acknowledges the importance of non-CO₂ emissions, including methane and nitrous oxide. Recent IMO discussions have focused on lifecycle greenhouse gas accounting, methane measurement methodologies, and “chain of custody” systems capable of tracking the origin and emissions profile of marine fuels throughout supply chains. The IMO’s Marine Environment Protection Committee (MEPC) has also advanced work on mandatory fuel standards and market-based measures intended to enter into force around 2027.
At its 84th session in May 2026, the IMO confirmed continued work on the so-called IMO Net-Zero Framework, including negotiations on medium-term measures and new guidelines for onboard methane and nitrous oxide emissions measurements from marine diesel engines. The discussions highlighted the growing importance of methane monitoring, reporting and verification (MRV) systems in global shipping governance.
The European Union has moved considerably faster and further than the IMO in regulating maritime methane emissions. Dissatisfied with the pace of international negotiations, the EU incorporated shipping into its “Fit for 55” climate package. Maritime transport now forms part of the EU Emissions Trading System (EU ETS), while additional obligations arise under the FuelEU Maritime Regulation and the EU Methane Regulation.
The inclusion of shipping in the EU ETS represents one of the most important developments in maritime climate regulation. Since January 2024, large ships calling at EU ports must monitor and report CO₂ emissions and surrender allowances for those emissions. From January 2026, methane and nitrous oxide emissions are also covered.
The EU ETS applies to all large ships above 5,000 gross tonnage entering EU ports, irrespective of flag. It covers 100% of emissions from voyages between EU ports and 50% of emissions from voyages between EU and non-EU ports. This geographical scope gives the EU regime significant global relevance because many international shipping routes involve European ports.
The inclusion of methane within the EU ETS is particularly important for LNG-fuelled shipping. Methane emissions are converted into CO₂-equivalent values using Global Warming Potential calculations, creating direct financial incentives to minimise methane slip. As carbon prices in the EU ETS remain relatively high, methane leakage can quickly translate into significant compliance costs for ship operators.
Alongside the ETS, the FuelEU Maritime Regulation introduces lifecycle greenhouse gas intensity targets for fuels used onboard ships. Unlike the EU ETS, which mainly follows a “tank-to-wake” approach, FuelEU Maritime adopts a “well-to-wake” methodology that includes upstream emissions associated with fuel production, processing and transport. This distinction is highly relevant for LNG because methane emissions often occur throughout the fuel supply chain, including extraction, liquefaction, transport and bunkering.
The EU Methane Regulation further complements this framework by imposing methane monitoring and reporting obligations across fossil fuel supply chains, including imported LNG. This creates a unique situation in which methane emissions linked to maritime LNG use are increasingly regulated both upstream and downstream.
An important challenge emerging from the new EU framework is the growing complexity of MRV systems. The verification burden has become substantial, especially for large fleets and LNG-powered vessels where methane measurement is technically demanding.
Industry experience already demonstrates the operational implications of these new requirements. According to DNV, many companies underestimated the complexity of emissions verification and the importance of data quality management. Accurate methane monitoring increasingly requires digitalised reporting systems, continuous emissions tracking and close cooperation between shipowners, verifiers and regulators.
At the same time, the regulatory pressure is accelerating innovation. New engine technologies are being developed to minimise methane slip, while shipowners are increasingly evaluating alternative fuels such as methanol, ammonia and hydrogen-based fuels. Methane regulation therefore acts not only as a compliance obligation but also as a broader industrial and technological driver for maritime decarbonisation.
Effective methane regulation in maritime transport will require greater convergence between IMO and EU approaches. Shipping is a global industry, and fragmented standards increase compliance costs and operational uncertainty. At the same time, methane emissions cannot remain insufficiently regulated given their significant climate impact. The current EU approach demonstrates that methane can be integrated into carbon pricing, lifecycle accounting and fuel standards simultaneously. Whether the IMO will adopt similarly comprehensive measures at global level remains one of the key unanswered questions for the future of maritime decarbonisation.
