Maritime shipping

Sailing boat and container ship in the harbor of HamburgClick to enlarge
Sailing boat and container ship in the harbor of Hamburg
Source: FG II 2.3 / UBA

More and larger ships are sailing the world's oceans. Due to their high tonnages, ocean-going vessels can be a comparably environment-friendly means of transport. There is still considerable potential to design and construct them in such a way that they pollute the environment less. Proposals need to be developed and implemented at all levels of maritime policy..

Table of Contents


Facts about maritime shipping and its environmental impact

About 6,000 years ago, ships took up conquering the oceans and humans have been making use of maritime transport for centuries. In the beginning, mainly sailing ships ploughed the seas but today huge freighters, container vessels and cruise liners do so and pollute the oceans in a variety of ways.

Globally, maritime transport has been increasing more or less continuously over decades. Today, in 2021, about 90 per cent of world trade is shipped by sea. About one third of vessels arrive in or depart from a European harbor. The North and Baltic Seas are the world's most frequented seas. By way of example, more than 30,000 vessels travel the North/Baltic Sea Canal annually and about 2,000 vessels cross the Baltic Sea each day at any time.

In close vicinity to the German coast, maritime shipping in the North Sea masses in the Southern German Bight and in the Baltic Sea in the Kadettrinne. In these coastal areas, unique extensive ecosystems are to be found, e.g. the Wadden Sea and its eelgrass meadows or mussel banks. Heavy maritime traffic and especially shipping accidents releasing vast amounts of oil and other pollutants into the sea seriously impact these ecosystems and their biocoenoses.

Maritime shipping is significantly polluting the marine environment. Hazardous substances in anti-fouling ships’ paint, the introduction of ICCT Report 2017, p. 14 , Umweltbundesamt, 2016, CO2 emissions from maritime traffic, Third IMO GHG Study 2014.


Maritime Transport Regulations

Since maritime transport is globally oriented, the International Maritime Organisation (IMO) is the entity to regulate things. One body in this organization, the Marine Environmental Protection Committee (MEPC) deals with issues regarding environmental protection. Requirements concerning environmental protection and maritime shipping are predominantly laid down in the Convention for the Prevention of Pollution from Ships (MARPOL).

MARPOL comprises the original agreement, two additional protocols and six annexes. Annexes I to VI regulate the different kinds of pollution from ships:

  • Annex I: Regulations for the Prevention of Pollution by Oi
  • Annex II: Regulations for the Control of Pollution by Noxious Liquid Substances in Bulk
  • Annex III: Regulations for the Prevention of Pollution by Harmful Substances Carried by Sea in Packaged Form
  • Annex IV: Regulations for the Prevention of Pollution by Sewage from Ships

Annex V: Regulations for the Prevention of Pollution by Garbage from Ships Annex VI: Regulations for the Prevention of Air Pollution from Ships

Detailed information on the contents of the different annexes are to be found on the website of the Federal Maritime and Hydrographic Agency (Bundesamt für Seeschifffahrt und Hydrographie, BSH).

Further important IMO Conventions regarding environmental protection and maritime shipping are:

  • International Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter 1972 (London Convention) and its updating Protocol of 1996 (London Protocol)
  • International Convention on the Control of Harmful Anti-Fouling Systems on Ships (AFS Convention; adopted 2001, in force since 2008)
  • International Convention for the control and Management of Ships’ Ballast Water and Sediments (Ballast Water Convention; adopted 2004, in force since 2017)
  • International Convention for the Safe and Environmentally Sound Recycling of Ships (Hong Kong Convention, adopted 2009 but not yet in force) and especially regarding the waters of the Arctic and Antarctic the
  • Polar Code

For additional information on the cited conventions visit On European level, maritime shipping and environmental protection are addressed in both the Convention for the Protection of the Marine Environment of the North-East Atlantic (⁠OSPAR⁠ Convention; 1992) and the Convention on the Protection of the Marine Environment of the Baltic Sea Area (Helsinki Convention; 1992). The Green Paper (2006) and the Blue Paper (2007) regarding the future maritime policy of the European Community reveal a lot of problems with regard to maritime traffic and strategies to solve them. The Blue Paper includes, among others, an action plan for the European Commission delineating badly needed measures with respect to maritime shipping (among others, measures to reduce air pollution). The EU Marine Strategy Framework Directive (MSFD) originates from ideas developed in the Blue Paper and entered into force in 2008. It is an attempt to incorporate an integrative policy approach aiming at facilitating the sustainable use of the European seas and at protecting and safeguarding the marine ecosystems in order to reach or preserve a good ecological status of the marine environment by 2020.

Since maritime traffic is an international mode of transport, it is difficult to take and implement highly effective measures in this field even on the national level. Regulations of international agreements indeed are transposed into German law and are reflected, for example, in the Ordinance on the environmentally compliant behavior within maritime shipping. It is the basis for taking actions against offences in Germany. However, shipping companies are free to choose its flag State, i.e. the State where the ship is registered and whose flag it carries. Pursuant to Article 91(1) of the United Nations Convention on the Law of the Sea, "… ships have the nationality of the State whose flag they are entitled to fly". Additionally, Article 94(1) of this Convention prescribes that "every State shall effectively exercise its jurisdiction and control in administrative, technical and social matters over ships flying its flag". For financial reasons, shipping companies often choose "flags of convenience", i.e. States with legal and tax systems fixing lower labor costs due to lower levies than, for instance, in Germany. These States neither implement consistently maritime (shipping) law nor do they prosecute infringements. Pursuant to Article 17 of the Convention on the Law of the Sea, ships of flag States may not be debarred from enjoying the right of innocent passage of the territorial sea of other States.

In principle, a ship may not be controlled, fines not imposed and penal measures taken until it has called a port. Depending on the State, the control of compliance with environmental protection regulations and, if necessary, the application of sanctions are more or less ambitious. It is often difficult to prove an infringement or a criminal offence at sea. In addition, the fines and penalties are comparatively low compared to the benefit the shipowner or charterer derives from the infringement. Sailing, for example, with higher sulphurous fuel than permitted means saving a large deal of costs compared to possible penalties, provided an infringement can be proven and sanctioned by the authorities at all.


Oil Pollution

Oil disasters, such as those caused by both the tankers ERIKA (1999 off the French coast of Brittany) and PRESTIGE (2002 off the north-west coast of Spain), must be reduced in number and severity. Oil spills and oil pollution may heavily damage marine ecosystems. Except a few heavy oils, oil first floats at the water surface. Low-viscosity oils (lighter crude oils and most oil products) spread very quickly and form a thin layer. Viscous oils, such as heavy oil, spread more slowly and form thicker oil slicks. Stronger winds and swell make disaggregate low-viscosity oil into drops and viscous oil into bigger lumps. While the larger ones remain directly at or below the surface and, if it is low-viscosity oil, coalesce again, droplets below a certain size remain stable in the water and slowly sink into deeper water layers or are washed up on the shore.

Oil slicks extenuate the swell so that seabirds often mistake the smooth surface for a resting place and alight. As a result, the viscous oil adheres to the birds’ feathers, destroys the thermal insulation and, in part, their buoyancy, and is ingested when the birds attempt to clean their oil-coated feathers. This can lead to widespread deaths of seabirds by suffocation, hypothermia, drowning and poisoning.

If the oil reaches the shore, it first accumulates there. In the course of time, it is washed off again, especially on shores with strong surf and thus shifted several times in the course of changing weather and tidal conditions. Oil of still relatively low viscosity sedimented ashore may poison or suffocate soil organisms such as worms or snails.

Not only nature is endangered: uses like fishing, tourism and coastal protection are also affected. Especially in sensitive marine areas, such as the Wadden Sea or polar waters, an oil spill would be an ecological disaster entailing long-lasting impacts. This is the reason why it is necessary to continue creating, on an international level, appropriate legal conditions in order to increase ship safety and prevent oil pollution.

For example, following the accident of the oil tanker 'Exxon Valdez' off Alaska in 1989, the IMO Environment Committee decided in December 2003 to tighten the age limit for single-hull oil tankers and to ban the transport of heavy fuel oil in single-hull tankers with a deadweight tonnage of more than 5,000 tons. Since that time, tankers with a deadweight tonnage of 5,000 tons and more had to be equipped with a double hull. This second hull is intended to prevent oil from leaking after a collision.

In Germany, the Central Command for Maritime Emergencies (CCME) – a joint institution of the German Federal Government and the Federal Coastal States - ensures a mutual maritime emergency management in the North and Baltic Seas, including in the event of oil spills from ships and ship accidents. Overall, it pools responsibility for planning, preparation, exercises and implementation of fire-fighting measures. It is also responsible for the care of injured persons and assistance as well as for salvage in complex damage situations at sea and for combating pollution accidents, including oil spills.

In particular, the section ’Marine Pollution Response Inshore’ of the CCME organizes oil and pollutant accident prevention for the five North German coastal countries in the coastal areas, river estuaries, harbors, shores and beaches. It draws up principles for precautionary and control measures, develops control strategies and techniques and procures the necessary resources such as ships and equipment for combating oil spills and pollution accidents and coordinates their deployment. Being part of the Incident Command Centre, it sets the targets for coastal pollution control measures in the case of major accidental water pollution and, equally to smaller accidents, provides expert service for local emergency services. Last but not least the CCME has supported several other countries in combatting oil spills e.g. by sending their special ships to the regions concerned.

For the countries bordering the Baltic Sea, the HELCOM RESPONSE working group has the task of ensuring that the appropriate equipment is timely available in the event of a shipping accident and the resulting oil pollution. Routines and exercises at sea are intended to ensure that the response to an accident can be carried out immediately in coordination with neighboring states. RESPONSE also endeavors to promote current developments in the field of security and risk prevention in international bodies. In addition, this group coordinates surveillance flights along the shipping routes in the Baltic Sea region with the aim of quickly identifying potential sources of illegal oil pollution.

A further HELCOM working group (HELCOM MARITIME) attempts to ensure that agreed regulations in the field of shipping are monitored and complied with. Among other things, MARITIME identifies and supports activities that help to reduce pollutant discharges from ships and offshore installations. The group closely cooperates with other international organizations such as IMO.

Under the Bonn Agreement, the Contracting Parties Belgium, Denmark, France, Germany, the Netherlands, Norway, Sweden and the United Kingdom (1969) as well as the European Union (1983), Ireland (2010) and Spain (2019) agreed to help each other in the event of shipping accidents and in combating chronic pollution from ships and offshore installations (such as oil and gas rigs). An essential part of the work under the Bonn Agreement is aerial surveillance to detect large-scale pollution of the marine environment. Remote sensing systems are intended to be used for both promptly identifying sources of oil spills and slicks and assigning them to the polluter in order to take action against the offence.

The North Sea Network of Investigators and Prosecutors (NSN) was set up in 2002 to help enforce international regulations preventing pollution from ships in the North Sea. NSN is associated with the ⁠OSPAR⁠ Commission and cooperates with the Bonn Agreement. The counterpart of the NSN in the Baltic Sea is the Network of Prosecutors on Environmental Crime (ENPRO), working under the auspices of the Network of the Prosecutors General in the Baltic Sea region. Both networks meet regularly. They consider themselves a platform for exchanging information and best practices as well as discussing ways to pursue offences across borders. So far, NSN and ENPRO have primarily dealt with violations of MARPOL Annex I 'Prevention of Pollution by Oil'. Discussions are currently underway on whether the activities should be extended to include waste at sea. To this end UBA organized a seminar in November 2018. Representatives of both networks, of the European Maritime Safety Agency (EMSA), of shipping companies, port authorities and of other relevant national authorities attended this meeting.


Sewage from Ships

Particularly the regulations of MARPOL Annex IV 'Prevention of Pollution by Sewage from Ships', to which other conventions and national legislation refer, are relevant for the discharge of sewage from ships into the sea. In general, the discharge regulations of MARPOL Annex IV apply to ships, engaged in international voyages, of 400 gross tonnage and above or which are certified to carry more than 15 persons. Persons are considered to be both crew members and passengers. Recreational crafts are excluded from the regulations set out in MARPOL Annex IV.

The unregulated discharge of sewage into the sea is generally prohibited, except when the ship is discharging comminuted and disinfected sewage at a distance of more than three nautical miles from the nearest land (baseline). In special areas such as the Baltic Sea, stricter discharge regulations apply to passenger ships.  A passenger ship is any ship carrying more than 12 passengers. There, discharge is only permitted if the passenger ships have a treatment plant certified according to IMO standards and if the wastewater is treated in such a way that the discharge does not cause any visible floating solids or discoloration.

For the North Sea and the North-East Atlantic, which enjoy special protection under the ⁠OSPAR⁠ Convention, the regulations under MARPOL have been adopted with regard to the discharge of sewage. A special feature is that in 2011 the IMO has designated the Baltic Sea as the first and so far, only special area under MARPOL Annex IV, resulting in stricter regulations for the discharge of sewage from passenger ships in port. However, these regulations come into force only after all riparian states will have reported to the IMO that sufficient reception facilities for sewage from passenger ships are available in their ports. In the Baltic Sea area, the MARPOL regulations are also valid for smaller ships and recreational craft due to HELCOM (Annex IV), if they have a toilet on board. In this case, for example, sewage retention systems on board are obligatory and sewage has to be discharged in port.

The table below provides a summary on the most important regulations of MARPOL in general and taking a special area as an example.

Regulations regarding sewage discharge according to the Convention for the Prevention of Pollution from ships (MARPOL)
Regulations regarding sewage discharge according to the Convention for the Prevention of Pollution f
Source: German Environment Agency

On national level, the above-mentioned regulations are relevant for the discharge of sewage and specified in Article 9 paragraph 1 of the Ordinance on Environmentally Sound Behaviour in Maritime Shipping. The prohibition of discharging sewage pertains, ‘pursuant to MARPOL regulations, to all ships, exceeding a certain size, engaged in international voyages; it applies also to both all ships and recreational craft flying between German ports, sailing on the estuaries of navigable rivers, in coastal waters, and all ships and recreational craft flying the German flag on voyages between German ports.’ Especially in the Baltic Sea, it is added that 'pleasure craft which, contrary to article 6b paragraph 1 of the Ship Safety Regulation, are not equipped with a tank and are not subject to any exemption, may not sail in coastal waters'.

The German Environment Agency has commissioned an expert report on legal requirements for handling ship sewage, focusing on the categories of scrubber sewage, ballast water and ship-generated sewage.

The various levels of jurisdiction (international maritime and environmental law, European law, national law) are considered. Interference and contradictions of the rights and obligations resulting from the different levels of jurisdiction are highlighted. The focus is on the question of whether and how the Federal Republic of Germany copes with its obligations under international and European law, and how the relevant provisions have been integrated into the existing framework of national law.


Garbage from Ships

It is often difficult to clearly identify the origin of marine litter. The sources can vary considerably from region to region. At global scale, about 80 percent of marine litter originates from land-based sources. In the North-East Atlantic, including the North Sea, however, sea-based sources are of greater importance. Around 40 percent of marine litter findings on beaches come from fishing and shipping and another 40 percent from tourism and recreational activities. The main litter types recorded are plastic fragments, packaging and nets and ropes.

The disposal of garbage into the sea is regulated internationally by the IMO's MARPOL Annex V 'Prevention of Pollution by Garbage from Ships'. Bar defined exceptions (food waste, innoxious cargo residues, cleaning agents and additives, and animal carcasses), no waste may be disposed of from ships into the sea. Since January 2013, these regulations have been in force worldwide. Stricter regulations apply in particularly sensitive areas that have been designated as such due to their specific pelagic and ecological conditions. With effect from 1 October 1989, the Baltic Sea and, with effect from 18 February 1991, the North Sea are considered special areas. In the North Sea and the Baltic Sea, for example, animal carcasses may not be discharged en route. The discharge of food waste not comminuted or ground as well as of cargo residues not contained in wash water is prohibited. A synoptical table of the discharge provisions laid down in Annex V of the MARPOL Convention are to be seen from this IMO overview.

Regional conventions as well as national legislation refer to these regulations laid down in MARPOL Annex V. As integral part of the EU Plastics Strategy, the Directive on port reception facilities for the delivery of waste from ships has been amended in 2019 and entered into force on 7 June 2019. The amendment resulted inter alia in cost recovery systems based on the application of a 100% indirect fee for MARPOL Annex V waste, excluding cargo residues. Appropriate measures within the regional action plans of the regional Conventions for the North East Atlantic (⁠OSPAR⁠) and for the Baltic Sea (HELCOM) support these efforts. Environmentalists pressed for factoring the fees for the delivery of waste into the port fees in order to render the illegal dumping of waste into the sea and to save money for waste management economically unattractive.

Nevertheless, the marine litter findings on European beaches illustrate that obviously significant quantities of waste are still discharged at sea. In particular, this is due to illegal waste disposal from ships at sea, poor waste management on board ships and the lack of adequate port reception facilities for ship-generated waste. This situation should change for the better with the implementation of the amended Directive on port reception facilities for the delivery of waste from ships.


Air Pollution

MARPOL Annex VI ‘Prevention of Air Pollution from Ships’ includes requirements on air pollutant emissions and energy efficiency of seagoing ships. Regarding air pollutants from combustion, only requirements for sulphur oxide (SOx) and nitrogen oxide (NOx) emissions have so far been specified.

The exhaust gases from seagoing vessels negatively impact the environment, health and climate. Above all, sulphur oxides (SOx), particulate matter (including soot) and nitrogen oxides affect ecosystems, by, for example, contributing to ocean acidification and eutrophication.

The heavy fuel oil used in maritime transport contains large quantities of sulphur (up to 3.5 percent is permitted, which is 3,500 times the sulphur content permitted for European road traffic) and must be treated on board so that it can be used. This process produces residues (sludge) which have to be disposed of in the port, but some of which are still dumped illegally at sea. In addition to the significantly higher sulphur content compared to fuels for road transport, the high pollutant content of heavy fuel oil (including polycyclic aromatic hydrocarbons, PAHs and heavy metals) is problematic, as these substances are released into the environment through exhaust gases.

MARPOL Annex VI offers the opportunity of designating Emission Control Areas (ECAs) where more stringent limit values for sulphur content in fuel and for NOx emissions apply. In the North and Baltic Seas as well as off the North-American coast, which are Special Emission Control Areas (SECAs), the maximum sulphur content is limited to 0.10 per cent. Even this significantly reduced sulphur content is still 100 times higher than the permitted 0.001% sulphur content of fuels for road transport. At the 74th meeting of the Marine Environment Protection Committee (MEPC 74) in May 2019, the globally valid fuel sulphur limit for ships operating outside designated emission control areas was reduced from 3.5 percent to 0.50 percent. It took effect on January 1st, 2020.

As an alternative to the use of high-quality fuels, the use of Exhaust Gas Cleaning Systems (EGCS), so-called scrubbers, is permitted for sulphur emission reduction to achieve the limit values. In such a wet cleaning system, the ship’s exhaust gases are passed through atomized water. Due to the natural buffer capacity of seawater, the sulphur compounds are absorbed.

Wet EGCS are divided in open (OL) and closed loop (CL) EGCS, depending on the mode of operation. In OL systems the water is discharged directly into the sea, in CL systems the water is partly recirculated after treatment, the amount of water being discharged (bleed-off) is significantly lower than in OL systems. CL systems can run temporarily in zero discharge mode as the bleed-off can be stored in a holding tank. The discharge water of EGS contains several pollutants as polycyclic aromatic hydrocarbons (PAH), heavy metals, oil residues and nitrate. The water and waste discharges from EGCS are predominantly addressed at international level by MARPOL Annex VI and its linked guidelines. These guidelines were last updated in 2015 and include limit values (pH, PAH, turbidity, nitrate) (Resolution MEPC.259(68), commonly known as “2015 EGCS Guidelines”, MEPC (2015)).

The German Environment Agency has investigated the environmental impact of scrubber systems in a research project. Discharge water samples were taken on board of ships and analyzed in terms of heavy metals and PAHs. The distribution of discharge water and potential concentrations of pollutants were simulated with a dispersion model for the North and Baltic Seas. Results showed an acidic pH value and the presence of several pollutants such as heavy metals, polycyclic aromatic hydrocarbons (PAHs), oil residues and nitrate in relevant concentrations in EGCS discharge water. Furthermore, the discharge of scrubber wash water may entail a significant accumulation of pollutants in some areas of the Baltic Sea. Conclusion is that EGCS may improve the air quality in harbor cities and at sea but will shift atmospheric to marine pollution.

The project "Environmental Impacts of Exhaust Gas Cleaning Systems for Reduction of SOx on Ships" published in June 2021 provides an overall review on the status quo of EGCS, with special focus on discharge water. It is based on a literature review and covers technical aspects, market analyses, regulatory framework and research activities related to this topic. Further chemical and ecotoxicological assessments will be conducted.

Nitrogen oxides (NOx) from the combustion in the engine contribute to the eutrophication of ecosystems. Such additional nutrient input into the sea may become evident through an increased algae bloom and oxygen depletion affecting especially smaller coastal and inland waters as e.g. in the Baltic Sea. Regulation 13 of MARPOL Annex VI includes globally valid limit values for NOx emissions; unfortunately, these are however not very ambitious. The stricter limit values of tier III of MARPOL Annex VI valid in the special NOx emission control areas (NECAs) apply since 2016 to the waters off the North American coast and since 2021 to the North and Baltic Seas as well.

In order to reduce climate-damaging greenhouse gas emissions from maritime transport, shipping companies must monitor and report their respective emissions starting 1 January 2018. The German Emissions Trading Authority (Deutsche Emissionshandelsstelle, DEHSt) at the German Environment Agency is the competent authority for emissions monitoring in Germany. For detailed information on this topic please refer to the German Emissions Trading Authority’s website.



The growth of organisms such as barnacles and mussels on boat and ship surfaces below the waterline is known as fouling. Fouling on a ship's hull increases the water resistance of the ship and thus leads to both slower sailing and increased fuel consumption. At the same time, the spread of fouling organisms into foreign habitats is boosted.

All techniques impeding the settlement of organisms on surfaces are covered by the term ’anti-fouling’. The most common are biocide-containing coatings from which the biocides are permanently released and thus get into the surrounding water.

Anti-fouling coatings containing toxic tributyltin dominated the market for decades. Investigations revealed that TBT in anti-fouling paints have similar effects to that of hormones – messengers in the body regulating growth, reproduction and the immune system – and, as an example, may adversely affect the reproduction of marine gastropods. This phenomenon has been observed particularly in highly polluted coastal areas along the shipping routes and in ports of the North and Baltic Seas. When the IMO Anti-fouling Convention came into force in 2008, the use of TBT in antifouling agents for ships was therefore banned (see also UBA topic page 'Anti-fouling agents', German only).

Today, mainly copper compounds and/or organic biocides are the basis for effective anti-fouling coatings. At present, environmental risks of all biocides are being assessed on the basis of the EU Biocide Regulation (EU no. 528/2012). In a second step, all biocides-containing (anti-fouling) products are tested subsequently. This process is expected to be completed in 2027; after that date, only tested products will be on the market. Since all biocides pose a certain risk to the environment, there should be a switch to biocide-free anti-fouling systems wherever possible. It should also be verified that alternative products do not negatively impact the environment (cf. UBA publication ‘Anti-fouling in water sports’)


Introduction of non-indigenous species

To stabilize empty or half-empty vessels, seawater or harbor water is usually pumped into and discharged from tanks provided for this purpose: the ballast water. The water taken in makes it possible that organisms such as fish, mussels, algae and bacteria enter these tanks. When draining theses tanks in foreign ports, the organisms that have survived the transport may settle there. If the organisms find suitable living conditions, they can eliminate native species and possibly change an entire ecosystem. Closed ballast water systems, developed for container shipping and considered to be particularly compatible with marine ecosystems, could not gain acceptance up to now.

In February 2004, the Ballast Water Convention was adopted during a diplomatic conference at the IMO. The Convention provides for the treatment of ballast water on board each vessel so that the number of organisms discharged with the ballast water is greatly reduced. This can be achieved by using systems that treat the ballast water with chemicals (biocides) or UV light, for example. Mechanical cleaning with filters is often installed upstream. For more information on the environmental risk assessment of ballast water treatment please refer to the UBA topic page 'Ballast water treatment'.

To make the Ballast Water Convention operative, not less than 30 states whose merchant fleets together account for at least 35 per cent of the gross tonnage of the global merchant fleet had to ratify it. Germany ratified this convention on 20 June 2013. Finland's accession to the Ballast Water Convention on 8 September 2016 as the 52nd state made the tonnage go up to 35.14 %. The Convention thus entered into force one year later on 8 September 2017. Further information on ballast water and the implementation of the Ballast Water Convention in Germany are available on the website of the Federal Maritime and Hydrographic Agency.



Shipping noise

In water, noise propagates faster and over much longer distances than on land. In addition to sound-based seismic exploration, research, military and fishery search methods (sonar, echo sounding techniques) and the construction and operation of energy generation facilities (offshore wind and tidal energy), ships account for a large proportion of background noise in the water, particularly because they are continuous noise sources. In the northern hemisphere, ships are the main source of underwater noise of low frequency ranges. In the frequency range between 10 and 300 Hz, maritime shipping locally increases the noise level by 20 - 30 dB to more than ten times the natural background noise level.

Such underwater noise can negatively impact marine life. It may, for example, strongly reduce both, the communication space of cetaceans and seals and their ability to detect predators and result in driving them out of important habitats since the animals evade these noise-polluted areas; furthermore, it may induce a temporary or permanent threshold shift in their hearing ability.

In the long term, underwater noise can negatively affect the survival of marine life. High sound levels can cause injury or significant biological disturbance even at distances of several kilometers from the sound source. New findings on the actual extent of noise pollution in the North and Baltic Seas reveal that, for example, in the Kadett Channel and the Fehmarn Belt multiple vessels are permanently moving within earshot of harbor porpoises. Furthermore, construction noise intensifies background noise, e.g. during the construction of offshore wind energy plants in the North and Baltic Seas.

It is necessary to establish binding and appropriate noise protection criteria for the different noise sources in order to achieve a reduction of noise input into the oceans.

The International Maritime Organization (IMO) has drawn up recommendations for reducing underwater noise, which should already be taken into account in the design, construction and operation of ships - with the exception of naval vessels (IMO Resolution A.468(XII)). Since 1 July 2014, almost all ship newbuildings have also been subject to a mandatory noise regulation system on board seagoing vessels (Code on Noise Levels on Board Ships), which was adopted by Resolution MSC.337(91). In comparison to the above-mentioned IMO Resolution, this Resolution defines binding maximum noise level limits for engine and control rooms as well as for workshops, quarters etc., which have been or must be transposed into national law by the flag states.

In 1978, the best-known eco-label in Germany, the Blue Angel, was created. It is awarded to products and services which, from a holistic point of view, are particularly environmentally friendly and, at the same time, meet high standards of both, occupational health and usability.

Since 2009, this 'Blue Angel' may also be awarded to eco-friendly ship design (current version: January 2021). This eco-label addresses shipping companies or ship operators planning to build a new ship. Already during the design and construction of a ship, potentials for environmental protection should be used. For example, the streamlining of the fuselage may be optimized and thus result in fuel saving.

To learn more about the criteria and to what vessels the Blue Angel has been awarded, please refer to the corresponding pages Eco-friendly Seagoing Ship Design.