Learning effect in maritime compliance, emissions fall

Of the shipping companies that report to the NEa, 75% are based outside of the Netherlands (Figure 1). A total of 1,538 ships were included in the initial emission reports submitted by 1 April. The target group consists for 45% of container ships, chemical tankers and oil tankers that together account for more than 60% of the total reported emissions (Figures 2 and 3). 

The year 2025 was a turbulent one for the maritime sector, with a range of geopolitical developments that affected emissions in the sector, making accurate interpretation difficult. The year was characterised by increasing geopolitical instability, caused by international tensions and the imposition of import tariffs by the United States – all of which affects the maritime sector, which is inextricably linked to the global economy.

Transport patterns in shipping also changed, as much maritime traffic sought to avoid the Red Sea and the Suez Canal, partly because of Houthi attacks on vessels. This would normally have resulted in increased emissions since the most frequently-used alternative route along the Cape of Good Hope can add weeks to the journey time.

Notwithstanding this, the preliminary figures actually indicate a fall in emissions. In this, changes to the patterns of behaviour in intercontinental shipping movements – meaning that a lower proportion of these fall within the scope of the EU ETS because ships are more likely to use ports outside the EU – may be affecting the emissions we are seeing. Finally, it is possible that more (CO₂-neutral) biobased fuels were used in 2025[3]. 

As far as shipping companies are concerned, there have also been changes in terms of EU ETS compliance compared to the previous year. In accordance with the phased introduction of the ETS in Maritime Transport, shipping companies must surrender emissions allowances for 70% of the actual CO₂ emissions emitted in 2025 by 30 September 2026. In the previous year, this figure was 40% for emissions in 2024 and will increase further to 100% for emissions in 2026.

Another key development within international policy for improving the sustainability of shipping was the Net Zero Framework (NZF): the global initiative by the International Maritime Organisation (IMO) aimed at using worldwide regulation to reduce greenhouse gas emissions. However, the NZF has been postponed for a year in response to active lobbying from the United States, which means the role of the EU ETS will remain crucial in the years ahead in boosting sustainability in the maritime sector. Greater clarity as to whether the NZF will be adopted – and if so in what form – is expected in the fourth quarter of 2026, although pressure from the United States for its complete rejection continues to increase in the meantime.

[1] Reference date: 1 April (2024 and 2025). The press release from April 2025 cites a percentage of 60%: this concerns a narrower selection of emission reports that did not include reports that were verified but had not yet been submitted to the NEa verifier.

[2] By 17 April 2026, verified emission reports had been submitted by 85% of the target group. The figure for total emissions was then calculated by means of linear extrapolation.

[3] In a few weeks’ time, the NEa will publish figures on the use of biomass within the context of EU ETS 1, which includes the emission trading system for the maritime sector.