Shipping and climate change

Illustration of a blue ship with lots of smoke
This page gives an overview of the impact of shipping on climate change, and of measures that could reduce emissions. These include the International Maritime Organisation's Energy Efficiency Design Index (EEDI) for new ships, measures to reduce fuel consumption such as reducing the speed of ships, and the prospects for a proposal by the European Commission for Monitoring, Reporting and Verification (MRV).

What is the impact of shipping on climate change?

The Third IMO greenhouse gas study estimates that for the period 2007–2012, on average, shipping accounted for approximately 2.7% of annual global CO2 and the study's scenarios project an increase of 50-250% in the period up to 2050.

Shipping CO2 emissions already increased by approximately 70% since 1990. Under a business-as-usual scenario and if other sectors of the economy reduce emissions to keep global temperature increases below 2 degrees Celsius, shipping could represent a whopping 10% of global GHG emissions by 2050.

What is the EEDI?

The Energy Efficiency Design Index (EEDI), approved in July 2011 by the International Maritime Organization (IMO), is the first globally-binding climate change standard. It will apply to 180 states and will enter into force on 1 January 2013. The index will require new ships to become more energy efficient, with standards that will be made increasingly more stringent over time.

Read our Questions and Answers on the IMO's EEDI.

How more fuel efficient will EEDI ships have to be, and by when?

Different classes of ship will have different standards to meet. However:

  • an overall 10% improvement target in vessels' energy efficiency will apply to new ships built between 2015 and 2019;
  • Ships built between 2020 and 2024 will have to improve their energy efficiency by 15 to 20%, depending on the ship type;
  • Ships delivered after 2024 will have to be 30% more efficient.

With the pace of fleet renewal, it will take one or two decades before the EEDI is fully effective for all ships, meaning it won't really make a meaningful difference to global shipping emissions before 2035.

However, it is anticipated that global CO2 reductions of 10 to 20% could be obtained in 2030, against a business-as-usual scenario.

Do the EEDI standards apply to all countries?

Yes, the EEDI standard will apply to all ships and all countries.

However, some countries may decide to waive the EEDI requirements. The waiver clause is limited in time and can only be applied for four years after the entry into force of the regulation. There is still no indication on the potential use of the waiver clause by some flag states but in any case, the impact of the waiver may be limited in the long term. A non-EEDI compliant ship will have a lower-value on the second-hand market and its ability to get a charter may be reduces, as charterers will prefer more efficient ships. In order to ease the introduction of the EEDI standards, developing countries also secured a process of technical assistance and technology transfer (still under discussion at the IMO).

Which kind of opposition did the approval of the EEDI encounter at IMO level?

Brazil, China, India, South Africa, Saudi Arabia and other developing countries strongly opposed the approval of the EEDI, not so much because they are against standards but because the EEDI is a measure that was designed to apply universally. For those countries, it sets a precedent against the climate policy principle of "common but differentiated responsibilities (CBDR)" i.e. that the developing world should have to do less to reduce emissions than developed countries.

How does the EEDI result in lower emissions?

If ships are more energy efficient, they will burn less fuel and - as a consequence - emit less carbon dioxide. The ICCT estimates that if the EEDI is implemented according to the original schedule, with compliant ships deployed starting in 2015, the regulation would save 15–45 million metric tons (Mt) of CO2 annually by 2020 and between 141 and 263 Mt of CO2 annually by 2030. If implementation is delayed by 4 years for all ships (application of the EEDI waiver provisions), the potential CO2 reductions would drop to between 2 and 6 Mt for 2020 and 80 and 143 Mt for 2030.

What is slow steaming?

Slow steaming refers to the practice whereby the speed of the ship is reduced. It basically means that the ship's engine is not used at full power, thus saving fuel, reducing CO2 and air pollutant emissions.

Reducing ship speed by 10% will lead to a 27% reduction of the ship's emissions. Overall, if all ships were to slow steam, the available capacity on the market would be reduced (more ships would be needed to carry the same transport work). If the additional emissions of building and operating these new ships were considered in the equation, then reducing the fleet's speed by 10% would lead to overall CO2 savings of 19%.

What is the purpose of developing slow steaming?

Reducing the speed of ships multiplies the positive effects of an energy efficiency index, as it makes them burn less fuel and therefore emit less CO2 and other greenhouse gases. It would also contribute to significantly cut their emissions of air pollutants such as NOx and PM, with costs greatly outweighing benefits. Slow steaming is often regarded as the most cost-effective way to reduce CO2 emissions as it can be done at almost no costs and translate into savings for the operators.

Is the industry already practicing slow steaming?

The industry started to slow steam in order to deal with the overcapacity resulting from the economic crisis and the subsequent drop in international trade. In a seminar organised in October 2011 by T&E and Seas at Risk, a representative of Maersk - the world's largest container shipping company - described how they have successfully been using slow steaming since 2007, decreasing their engines' load by 35% without any technical problems for ship owners. On the contrary, slow steaming has brought about fuel savings and reduced costs for maintenance and operational issues. The Maersk representative also said that his company sees no technical problems in implementing so-called super-slow steaming, which would mean decreasing the engine power by up to 90%.

Is regulated slow steaming legally and technically enforceable?

The findings of the first ever study on the feasibility of regulated slow steaming indicate that it is technically possible and legally enforceable without any major administrative burden and at no cost for the shipping industry. The report - carried out by the Dutch consultant CE Delft, the University of Southampton and the International Council on Clean Transportation (ICCT) and commissioned by T&E and Seas at Risk - recommends that a global speed limit for shipping be implemented with an international agreement to reduce the risk of retaliation. Read our briefing about this.

What is the MRV Proposal from the European Commission?

As shipping is the only sector without a cap on emissions at the EU level, in 2009 the EU committed to make a proposal to include shipping in the EU’s climate policy. However, the Commission announced in October 2012 that it would instead propose to simply monitor shipping emissions. The Commission thus brought forward a proposal in July 2013 requiring ships to implement a monitoring plan for CO2 emissions generated by voyages to or from EU ports that does not require any actual emissions reductions. While this proposal is a step in the right direction, it lacks ambition and is unlikely to deliver emissions cuts. The Parliament and Council now have the opportunity to change that by creating a robust Monitoring, Reporting and Verification (MRV) system that will really incentivise emissions reductions, ensure EU law on shipping air pollution is enforced and provide shipping users with transparent data to identify the most efficient ships. Read our briefing to learn more.