Press release

Slow down: Reducing shipping speed helps tackle the climate crisis with immediate effect

September 2, 2021
  • Climate crisis: Mediterranean Sea projected to heat up by 1.8 to 3.5 degrees until 2100
  • Climate offenders: New EMTER Report says that maritime transport is responsible for 5% of all greenhouse gas emissions from transport in the EU.
  • If maritime shipping were a country, it would rank 6th among emitters of greenhouse gases.
  • Global maritime shipping traffic annually causes more CO2 emissions than Germany.
  • Global GHG emission from shipping expected to further increase by approximately 90-130% until 2050 if no strong action is taken.
  • Paris climate goals get out of reach – speed reduction is an immediate, effective and cost-efficient measure to reduce GHG emissions.

Shipping is among the worst climate offenders, even though there’s an easy and readily available solution: “Reduce speed!”, says Nicolas Entrup of OceanCare. The marine conservation organisation calculated the benefits of slower shipping for environment and climate.

The first ever European Maritime Transport Environmental Report (EMTER) by the European Maritime Safety Agency (EMSA) and the European Environment Agency (EEA) was released on September 1st, 2021. It provides a helpful overview of the impacts by the maritime transport sector within the European Union. OceanCare provides context and comments, but also a clear call to action how to actively address this sector’s impact both on the ocean and the world’s climate.

About 90% of world trade happen by maritime transport. Within the European Union it carries 77% of the external trade and 35% of intra-EU trade. A study by the European NGO “Transport & Environment” found that shipping is among the worst climate offenders, emitting about 139 million tons of CO2 in Europe (in 2018), mainly through cargo shipping. More than two thirds of these emissions – 112 million tons – originate from ships transporting consumer goods or bulk cargo. This is expected to become worse as maritime traffic keeps growing alongside consumption and international trade.

Reducing speed would have additional positive effects on the oceans. It would reduce other air pollutants like black carbon. The peril of colliding with whales would be reduced by 80%. Whale dung is essential for marine oxygen production and whales themselves are considered to be extremely important for carbon sequestration.

Last but not least, it would reduce underwater noise emissions, a major source of stress for marine life, by 40% to 67%. According to the EMTER Report, underwater noise levels have doubled within EU waters between 2014 and 2019, with severe impacts OceanCare has been raising concerns about for many years. The bulk of noise emissions is caused by container ships, followed by cargo ships and tankers. Already in 2018, the French government calculated that an oil tanker sailing at 11 instead of 12 knots would consume 18% less fuel. Reducing speed to ten knots would even result in fuel savings by 30%. The EMTER Report also stresses that ‘slow steaming’ can play a significant role in reducing GHG emissions. This is also the conclusion of two studies commissioned by the Belgian Ministry for Environment and reviewed by IFAW and OceanCare experts, which were presented during a webinar on 30th March 2021 and stressed the multiple environmental benefits of such a measure.

“There are several ideas about how to reach climate goals in maritime shipping, including more efficient engines and propellers, improved ship design, or using renewable energy and alternative fuels. However, none of these technologies is broadly available for large cargo ships at present. This will take some more years, which we cannot afford,” says OceanCare policy expert Carlos Bravo. “By contrast, reducing speed is not only immediately available but also has the largest effect on climate and environment. Another huge advantage of this measure is that it doesn’t afford costly investments in new technologies.”

Halve greenhouse gas emissions by 2050

In 2018, the members of the International Maritime Organisation (IMO) came to the agreement to halve annual greenhouse gas emissions by 2050 compared to 2008. France called for global speed reduction for ships just one year later – the commitments made at the IMO must be followed up as quickly as possible – but encountered fierce opposition.

“To reach this climate goal, other countries have to join in. Reducing speed has an immediate and powerful effect. However, that’s only feasible when everybody is on board. No shipowner will accept a competitive disadvantage. OceanCare therefore calls for a quick supranational and binding rule that establishes the so-called ‘slow steaming’ for all vessels globally at the same time,” says Entrup.


Maritime transport is the backbone of international trade and the global economy. Around 90% of world trade involves transport by sea. Europe is among the world’s main maritime centres: it has 329 major seaports and around one third of the world’s cargo fleet is controlled by EU companies. In the EU, it carries 77% of external trade and 35% of intra-EU trade, and rising. Total greenhouse gas emissions from international maritime transport increased from 977 million tonnes in 2012 to 1,076 million tonnes in 2018 (+9.6%). If shipping were a country, it would be the sixth largest greenhouse gas emitter.

In 2020, the IMO projected the sector’s GHG emissions to increase from about 90% of 2008 emissions in 2018 to 90-130% of 2008 emissions by 2050 for a range of plausible long-term economic and energy scenarios, if no action is undertaken. Even if these predictions do not take account of the effects of the COVID-19 pandemic, which could slow down the growth of the maritime sector for some years, such growth in emissions is not compatible with the EU’s 2050 climate neutrality target.

“We are experiencing a summer marked by the climate crisis: storms, floods, heat waves, devastating fires. The Mediterranean is hit particularly hard. From 1985 to 2006, sea temperature already rose by 0.4 degrees per decade during the period between 1985 and 2006. Until 2100 it is expected to rise by 1.8 to 3.5 degrees compared to the period between 1961 and 1990. Everyone should have realised that legislators need to act quickly. Speed reduction in transport shipping is an immediately implementable, very efficient measure with concrete, measurable CO2 reduction and additional positive effects. It protects the ocean and the Mediterranean Sea – and counteracts the climate crisis,” says OceanCare expert Carlos Bravo. “Climate extremes all over the Mediterranean are a call for determined action to make maritime transport more eco-friendly. Now is the moment to act. The ball is in the European countries’ court,” Bravo concludes.