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Low carbon shipping and air pollution control


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Emissions from ships exhausts into the atmosphere can potentially be harmful to human health and cause acid rain and may also contribute to global warming.

To ensure that shipping is cleaner and greener, IMO has adopted regulations to address the emission of air pollutants from ships and has adopted mandatory energy-efficiency measures to reduce emissions of greenhouse gases from international shipping, under Annex VI of IMO’s pollution prevention treaty (MARPOL).

Shipping and Climate Change videos

These three short videos explain IMO's energy-efficiency requirements and highlight capacity-building as a way to promote uptake of the measures.

Combatting air pollution from shipping

IMO regulations to address air pollutants from international shipping, particularly sulphur oxide (SOx) and nitrogen oxide (NOx), have been successful in lowering the amount of those pollutants being emitted from ships.  Further strengthening of the requirements are set to continue. 

There are global caps, with more stringent requirements in Emission Control Areas or ECAS.  Currently, there are four ECAS designated by IMO:

  1. Baltic Sea area (SOx only);

  2. North Sea area (SOx only);

  3. North American area (SOx, NOx and PM); and

  4. United States Caribbean Sea area  (SOx, NOx and PM).

In SECAS, the sulphur cap is 0.10% m/m (mass/mass). Outside SECAS, the global sulphur cap is 3.50%, falling to 0.50% from 1 January 2020.

MARPOL Annex VI regulations to restrict air pollution from ships were first adopted in 1997. ​​​​​​A revised  Annex VI was adopted in 2005 and it entered into force in  2010, phasing in a progressive reduction in sulphur oxide (SOx) from ships and further reductions in nitrogen oxide (NOx) emissions from marine engines.

Read more about prevention of air pollution from ships here.

Energy-efficiency requirements

IMO is the only organization to have adopted energy-efficiency measures that are legally binding across an entire global industry, applying to all countries.

IMO has established a series of baselines for the amount of fuel each type of ship burns for a certain cargo capacity. Ships built in the future will have to beat that baseline by a set amount, which will get progressively tougher over time. By 2025, all new ships will be a massive 30% more energy efficient than those built in 2014.

Under the energy-efficiency regulations, existing ships now have to have an energy efficiency management plan in place, looking at things like improved voyage planning, cleaning the underwater parts of the ship and the propeller more often, introducing technical measures such as waste heat recovery systems, or even fitting a new propeller.

The energy-efficiency requirements were adopted as amendments to MARPOL Annex VI  in 2011 and they entered into force on 1 January 2013​. The regulations make mandatory the Energy Efficiency Design Index (EEDI)  mandatory for new ships, and the Ship Energy Efficiency Management Plan (SEEMP) is made a requirement for all ships.

Read more on energy efficiency requirements here.

IMO continues to work on refining guidance and on the implementation of the regulations, through its Marine Environment Protection Committee (MEPC). The Organization is also promoting technology transfer through capacity-building projects.


Capacity-building projects
​It is important we work with Member States and industry towards instilling a culture that looks towards best practices in achieving lower emissions. This is the focus of two IMO capacity-building projects.
The first is the GEF-UNDP-IMO Global Maritime Energy Efficiency Partnership (GloMEEP), Project, which aims to build understanding and knowledge of technical and operational energy-efficiency measures to lead maritime transport into a low-carbon future. The two-year project involves 10 lead pilot countries (Argentina, China, Georgia, India, Jamaica, Malaysia, Morocco, Panama, Philippines and South Africa) and aims to create global, regional and national partnerships to build the capacity to address maritime energy efficiency and for countries to bring this issue into the mainstream within their own development policies, programmes and dialogues. The first national workshop under the Project was held in December 2015.
The second is an ambitious €10 million IMO-European Union Project on Capacity Building for Climate Change Mitigation in the  Maritime Shipping Sector which is a four-year project to establish a global network of Maritime Technology Cooperation Centres (MTCCs). The aim of the Global MTTC Network (GMN) project is to help beneficiary countries limit and reduce GHG emissions from their shipping sectors through technical assistance and capacity building. It will encourage the uptake of innovative energy-efficiency technologies among a large number of users through the widespread dissemination of technical information and know-how. This will heighten the impact of technology transfer.

The four-year project will target five regions – Africa, Asia, the Caribbean, Latin America and the Pacific. These have been targeted for their significant number of Least Developed Countries (LDCs) and Small Island Developing States (SIDS). The first two host institutions were confirmed in December 2016. Shanghai Maritime University in China will host the MTCC for the Asia region (MTCC-Asia), while the University of Trinidad and Tobago will host MTCC-Caribbean. In February 2017, IMO confirmed that Jomo Kenyatta University of Agriculture and Technology (JKUAT), Kenya, will host MTCC-Africa. 

Studies and reports

(The views and conclusions expressed in the studies are those of the authors)

  • Third IMO GHG Study (2014)

  • Investigation of appropriate control measures (abatement technologies) to reduce Black Carbon emissions from
    international shipping (2015)

  • Study of Emission Control and Energy Efficiency Measures for Ships in the Port Area (2015)

  • Studies on the feasibility and use of LNG as a fuel for shipping (2016)


IMO participates in the UN Climate Change Conferences, providing updates to the Subsidiary Body for Scientific and Technological Advice (SBSTA 43) under agenda item 10 on Emissions from fuel used for international aviation and maritime transport. See submissions to COP 22 and COP 21
Although shipping was not included in the final text of the Paris Agreement, adopted in 2015, IMO has set itself a long-standing mandate to contribute to the fight against climate change by addressing greenhouse gas emissions from ships.