Environmental impact of shipping

01The environmental impact of shipping include air pollution, water pollution, acoustic, and oil pollution.

02Ships are responsible for more than 18% of nitrogen oxides pollution and 3% of greenhouse gas emissions.

03Although ships are the most energy-efficient method to move a given mass of cargo a given distance, the sheer size of the industry means that it has a significant effect on the environment.

04The annual increasing amount of shipping overwhelms gains in efficiency, such as from slow steaming.

05The growth in ton-kilometers of sea shipment has averaged 4% yearly since the 1990s, and it has grown by a factor of 5 since the 1970s.

06The fact that shipping enjoys substantial tax privileges has contributed to the growing emissions.

07Ballast water Ballast water discharges by ships can have a negative impact on the marine environment.

08Cruise ships, large tankers, and bulk cargo carriers use a huge amount of ballast water, which is often taken on in the coastal waters in one region after ships discharge wastewater or unload cargo, and discharged at the next port of call, wherever more cargo is loaded.

09Ballast water discharge typically contains a variety of biological materials, including plants, animals, viruses, and bacteria.

10These materials often include non-native, nuisance, invasive, exotic species that can cause extensive ecological and economic damage to aquatic ecosystems along with serious human health problems.

11Sound pollution Noise pollution caused by shipping and other human enterprises has increased in recent history.

12The noise produced by ships can travel long distances, and marine species who may rely on sound for their orientation, communication, and feeding can be harmed by this sound pollution.

13The Convention on the Conservation of Migratory Species has identified ocean noise as a potential threat to marine life.

14The disruption of whales' ability to communicate with one another is an extreme threat and is affecting their ability to survive.

15According to a Discovery Channel article on sonic sea journeys deep into the ocean over the last century, extremely loud noise from commercial ships, oil and gas exploration, naval sonar exercises, and other sources has transformed the ocean's delicate acoustic habitat, challenging the ability of whales and other marine life to prosper and ultimately to survive.

16Whales are starting to react to this in ways that are life-threatening.

17Despite sonar's military and civilian applications, it is destroying marine life.

18According to IFAW Animal Rescue Program Director Katie Moore, there's different ways that sounds can affect animals.

19There's that underlying ambient noise level that's rising and rising, and rising that interferes with communication and their movement patterns.

20And then there's the more acute kind of traumatic impact of sound that's causing physical damage or a really strong behavioral response.

21It's fight or flight.

22Wildlife collisions.

23Marine mammals such as whales and manatees risk being struck by ships, causing injury and death.

24For example, a collision with a ship traveling at only 15 knots has a 79% chance of being lethal to a whale.

25Ship collisions may be one of the leading causes of population decline for whale sharks.

26One notable example of the impact of ship collisions is the endangered North Atlantic right whale, of which 400 or fewer remain.

27The greatest danger to the North Atlantic right whale is injury sustained from ship strikes.

28Between 1970 and 1999, 35.5% of recorded deaths were attributed to collisions.

29From 1999 to 2003, incidents of mortality and serious injury attributed to ship strikes averaged one per year.

30From 2004 to 2006, that number increased to 2.6.

31Deaths from collisions has become an extinction threat.

32The United States National Marine Fisheries Service, NMFS, and National Oceanic and Atmospheric Administration, NOAA, introduced vessel speed restrictions to reduce ship collisions with North Atlantic right whales in 2008, which expired in 2013.

33However, in 2017, an unprecedented mortality event occurred, resulting in the deaths of 17 North Atlantic right whales, caused primarily from ship strikes and entanglement in fishing gear.

34Atmospheric pollution.

35Exhaust gases from ships are a significant source of air pollution, both for conventional pollutants and greenhouse gases.

36Conventional pollutants.

37Air pollution from ships is generated by diesel engines that burn high-sulfur-content fuel oil, also known as bunker oil, producing sulfur dioxide, nitrogen oxide and particulate, in addition to carbon monoxide, carbon dioxide, and hydrocarbons, which again leads to the formation of aerosols and secondary chemicals reactions, including formations of HCHO, ozone, etc.

38In the atmosphere, diesel exhaust has been classified by the U.S.

39Environmental Protection Agency, EPA, as a likely human carcinogen.

40The agency recognizes that these emissions from marine diesel engines contribute to ozone and carbon monoxide non-attainment, i.e., failure to meet air quality standards, as well as adverse health effects associated with ambient concentrations of particulate matter and visibility, haze, acid deposition, and eutrophication and nitrification of water.

41EPA estimates that large marine diesel engines accounted for about 1.6% of mobile-source nitrogen oxide emissions and 2.8% of mobile-source particulate emissions in the United States in 2000.

42Contributions of marine diesel engines can be higher on a port-specific basis.

43Ultra-low sulfur diesel, ULSD, is a standard for defining diesel fuel with substantially lowered sulfur contents.

44As of 2006, almost all of the petroleum-based diesel fuel available in Europe and North America is of a ULSD type.

45However, bunker oil is still available, and large marine engines are able to switch between the two types simply by opening and closing the respective valves from two different onboard fuel tanks.

46In 2016, the IMO adopted new sulfur emissions regulations for implementation by larger ships beginning in January 2020.

47Of total global air emissions, marine shipping accounts for 18-30% of the nitrogen oxides and 9% of the sulfur oxides.

48Sulfur in the air creates acid rain which damages crops and buildings.

49When inhaled, sulfur is known to cause respiratory problems and even increases the risk of a heart attack.

50According to Irene Blooming, a spokeswoman for the European Environmental Coalition sees at risk, the fuel used in oil tankers and container ships is high in sulfur and cheaper to buy compared to the fuel used for domestic land use.

51A ship lets out around 50 times more sulfur than a lorry per ton of cargo carried.

52Cities in the United States like Long Beach, Los Angeles, Houston, Galveston, and Pittsburgh see some of the heaviest shipping traffic, which has left local officials desperately trying to clean up the air.

53Increasing trade between the United States and China is helping to increase the number of vessels navigating the Pacific and is exacerbating multiple environmental problems.

54To maintain the level of growth China is experiencing, large amounts of grain are being shipped to China.

55The numbers of shipments are expected to continue increasing.

56In contrast to sulfur emissions, which depend on the fuel used, nitrous oxide emissions are primarily a function of combustion temperature.

57As air contains over 70% nitrogen by volume, some of it will react with oxygen during combustion.

58Given that those reactions are endothermic, a higher amount of nitrous oxides will be produced at higher combustion temperatures.

59However, other pollutants, particularly unburned or partially burnt hydrocarbons, also known as hyperfine particulates or soot, will be more common at lower combustion temperatures.

60So there is a trade-off between nitrogen oxides and soot, other than replacing ambient air with pure oxygen or some other oxidizing agent.

61The only ways to significantly reduce the nitrogen oxide emissions are via passing flue gases through a catalytic converter and or diesel exhaust fluid treatment, whereby an aqueous solution of urea reacts with the nitrous oxides in the flue gas to produce nitrogen, carbon dioxide, and water.

62However, both those options add cost and weight.

63Furthermore, the urea in diesel exhaust fluid is usually derived from fossil fuels, and therefore it is not carbon neutral.

64A third option entails the use of wet scrubbers that essentially spray seawater through the exhaust column as it is pumped through a chamber.

65Depending on the detailed engineering design attributes of the wet scrubber, these devices can wash out the sulfur oxides, soot, and nitrogen oxides from the engine exhaust, thus leaving a sludge that contains soot and various acidic compounds, or neutralized compounds, if alkaline substances are mixed in with the scrubbing liquid beforehand.

66This material can then be either treated via an onboard device, closed-loop system, or it can simply be dumped overboard, open-loop system.

67The discharged material can be harmful to marine life, especially in nearshore settings.

68In a recent study, the future of ship emissions has been investigated and reported that the growth of carbon dioxide emissions do not change with most common alternatives such as ultra-low sulfur diesel, ULSD, or liquefied natural gas, LNG, as well as growing volume of methane emission due to methane slip through the LNG supply chain.

69Methane is a much more powerful greenhouse gas than carbon dioxide per unit volume, and is only slowly broken down in the environment by various chemical, photochemical, and biological processes.

70In inland waters-based applications where sulfur cannot fully be removed from the fuel before combustion, desulfurization, flue gas scrubbing is commonly employed.

71However, this would add weight and cost on ships and produce a further waste stream, usually calcium sulfate if flue gases are scrubbed by being passed through calcium hydroxide solution, which would have to be disposed of, adding yet further cost.

72In addition, calcium hydroxide commonly being produced by calcination of calcium carbonate releases yet more carbon dioxide into the atmosphere.

73While this stream is comparatively small in relation to carbon dioxide emissions caused by combustion of fossil fuels, it needs to be taken into account as well, as part of a complete life cycle assessment.

74Localized air pollution One source of environmental stresses on maritime vessels recently has come from states and localities, as they assess the contribution of commercial marine vessels to regional air quality problems when ships are docked at port.

75For instance, large marine diesel engines are believed to contribute 7% of mobile source nitrogen oxide emissions in Baton Rouge and New Orleans, Louisiana.

76Ships can also have a significant impact in areas without large commercial ports.

77They contribute about 37% of total area nitrogen oxide emissions in the Santa Barbara, California area, and that percentage is expected to increase to 61% by 2015.

78Again, there is little cruise industry-specific data on this issue.

79They comprise only a small fraction of the world's shipping fleet, but cruise ship emissions may exert significant impacts on a local scale in specific coastal areas that are visited repeatedly.

80Shipboard incinerators also burn large volumes of garbage, plastics, and other waste, producing ash that must be disposed of.

81Incinerators may release toxic emissions as well.

82In 2005, Marple NX-6 came into force to combat this problem.

83As such, cruise ships now employ CCTV monitoring on the smokestacks as well as recorded measuring via opacity meter while some are also using clean burning gas turbines for electrical loads and propulsion in sensitive areas.

84Greenhouse gas emissions.

85Maritime transport accounts for about 3% of all greenhouse gas emissions, primarily carbon dioxide.

86According to the World Bank, in 2022, the shipping industry's 3% of global greenhouse gas emissions make it the sixth largest greenhouse gas emitter worldwide, ranking between Japan and Germany.

87Although the industry was not a focus of attention of the Paris Climate Accord signed in 2016, the United Nations and the IMO have discussed CO2 emissions goals and limits.

88The first intersessional meeting of the IMO working group on greenhouse gas emissions took place in Oslo, Norway in 2008.

89It was tasked with developing the technical basis for the reduction mechanisms that may form part of a future IMO regime to control greenhouse gas emissions from international shipping and a draft of the actual reduction mechanisms themselves, for further consideration by the IMO's Marine Environment Protection Committee, MEPC.

90In 2018, the industry discussed in London placing limits to cut levels from a benchmark of 2008 carbon dioxide emissions by 50% by the year 2050.

91Some methods of reducing emissions of the industry include lowering speeds of shipping, which can be potentially problematic for perishable goods, as well as changes to fuel standards.

92In 2019, international shipping organizations, including the International Chamber of Shipping, proposed creating a $5 billion fund to support the research and technology necessary to cut GHG emissions.

93Decarbonization of Shipping The decarbonization of shipping is an ongoing goal to reduce greenhouse gas emissions from shipping to net zero by, or around 2050, which is the goal of the International Maritime Organization, IMO.

94The IMO has an initial strategy.

95This includes the practice of lowering or limiting the combustion of fossil fuels for power and propulsion to limit emission of carbon dioxide, CO2.

96In July 2023, the IMO set a series of non-binding targets for cutting emissions, marking a significant step forward from the earlier 2018 plan.

97These targets, however, still fall short of complete alignment with the 2015 Paris Agreement goal of limiting global warming to 1.5 degrees Celsius above pre-industrial levels.

98The IMO is also developing new regulations aiming to reduce the greenhouse gas, GHG, intensity of ship fuel, and is planning to implement the world's first global, mandatory charge on GHG emissions by 2027.

99This charge is intended to incentivize the reduction of emissions across the global fleet.

100Oil spills Most commonly associated with ship pollution are oil spills.

101While less frequent than the pollution that occurs from daily operations, oil spills have devastating effects.

102While being toxic to marine life, polycyclic aromatic hydrocarbons, PAHs, the components in crude oil are very difficult to clean up and last for years in the sediment and marine environment.

103Marine species constantly exposed to PAHs can exhibit developmental problems, susceptibility to disease, and abnormal reproductive cycles.

104One of the more widely known spills was the Exxon Valdez incident in Alaska.

105The ship ran aground and dumped a massive amount of oil into the ocean in March 1989.

106Despite efforts of scientists, managers, and volunteers, over 400,000 seabirds, about 1,000 sea otters, and immense numbers of fish were killed.

107Wastewater Blackwater is sewage, wastewater from toilets, and medical facilities, which can contain harmful bacteria, pathogens, viruses, intestinal parasites, and harmful nutrients.

108Discharges of untreated or inadequately treated sewage can cause bacterial and viral contamination of fisheries and shellfish beds, producing risks to public health.

109Nutrients in sewage, such as nitrogen and phosphorus, promote excessive algal blooms, which consumes oxygen in the water and can lead to fish kills and destruction of other aquatic life.

110Graywater is wastewater from the sinks, showers, galleys, laundry, and cleaning activities aboard a ship.

111It can contain a variety of pollutant substances, including fecal coliforms, detergents, oil and grease, metals, organic compounds, petroleum hydrocarbons, nutrients, food waste, medical and dental waste.

112Sampling done by EPA and the state of Alaska found that untreated graywater from cruise ships can contain pollutants at variable strengths, and that it can contain levels of fecal coliform bacteria several times greater than is typically found in untreated domestic wastewater.

113Graywater has potential to cause adverse environmental effects because of concentrations of nutrients and other oxygen-demanding materials.

114In particular, graywater is typically the largest source of liquid waste generated by cruise ships, 90 to 95 percent of the total.

115Estimates of graywater range from 110 to 320 liters per day per person, or 330,000 to 960,000 liters per day for a 3,000 person cruise ship.

116A large cruise ship, 3,000 passengers and crew, generates an estimated 55,000 to 110,000 liters per day of blackwater waste.

117The cruise line industry dumps 970,000 liters, 255,000 U.S.

118gal of graywater and 110,000 liters, 30,000 U.S.

119gal of blackwater into the sea every day.

120Marple Annex 4 was brought into 4 September 2003, strictly limiting untreated waste discharge.

121Modern cruise ships are most commonly installed with a membrane bioreactor type treatment plant for all blackwater and graywater, such as GNO, Xenon, or Rockhem bioreactors which produce near-drinkable quality effluent to be reused in the machinery spaces as technical water.

122Solid waste Solid waste generated on a ship includes glass, paper, cardboard, aluminum, and steel cans and plastics.

123It can be either non-hazardous or hazardous in nature.

124Solid waste that enters the ocean may become marine debris and can then pose a threat to marine organisms, humans, coastal communities, and industries that utilize marine waters.

125Cruise ships typically manage solid waste by a combination of source reduction, waste minimization, and recycling.

126However, as much as 75% of solid waste is incinerated on board and the ash typically is discharged at sea, although some is landed ashore for disposal or recycling, marine mammals, fish, sea turtles, and birds can be injured or killed from entanglement with plastics and other solid waste that may be released or disposed off of cruise ships.

127On average, each cruise ship passenger generates at least 2 pounds of non-hazardous solid waste per day.

128With large cruise ships carrying several thousand passengers, the amount of waste generated in a day can be massive.

129For a large cruise ship, about 8 tons of solid waste are generated during a one-week cruise.

130It has been estimated that 24% of the solid waste generated by vessels worldwide by weight comes from cruise ships.

131Most cruise ship garbage is treated on board, incinerated, pulped, or ground up for discharge overboard.

132When garbage must be offloaded, for example, because glass and aluminium cannot be incinerated, cruise ships can put a strain on port reception facilities, which are rarely adequate to the task of serving a large passenger vessel.

133Bilge water On a ship, oil often leaks from engine and machinery spaces or from engine maintenance activities and mixes with water in the bilge, the lowest part of the hull of the ship.

134Though bilge water is filtered and cleaned before being discharged, oil in even minute concentrations can kill fish or have various sublethal chronic effects.

135Bilge water also may contain solid wastes and pollutants containing high levels of oxygen-demanding material, oil, and other chemicals.

136A typically large cruise ship will generate an average of 8 tons of oily bilge water for each 24 hours of operation.

137To maintain ship stability and eliminate potentially hazardous conditions from oil vapors in these areas, the bilge spaces need to be flushed and periodically pumped dry.

138However, before a bilge can be cleared out and the water discharged, the oil that has been accumulated needs to be extracted from the bilge water, after which the extracted oil can be reused, incinerated, and or offloaded in port.

139If a separator, which is normally used to extract the oil, is faulty or is deliberately bypassed, untreated oily bilge water could be discharged directly into the ocean, where it can damage marine life.

140Some shipping companies, including large cruise shipping lines, have sometimes violated regulations by illegally bypassing the onboard oily water separator and discharging untreated oily wastewater.

141In the U.S., these violations by means of a so-called magic pipe have been prosecuted and resulted in large fines, but in other countries enforcement has been mixed.

142International regulation Some of the major international efforts in the form of treaties are the Marine Pollution Treaty, Honolulu, which deals with regulating marine pollution from ships, and the UN Convention on Law of the Sea, which deals with marine species and pollution.

143Maritime governance from the 1950s up to the 1980s has been characterized by intergovernmental decision-making centralized around the IMO.

144However, this picture has been changing since the 1980s when regional initiatives in the EU and its member states began to play a larger role, partly due to an increasing dissatisfaction with the lacking regulation and enforcement efforts of the IMO.

145This has led to a new synergy developing between the EU and the IMO and other regional actors, broadly characterized as a polycentric mode of governance.

146The polycentric synergy of the EU and IMO has largely been driven by the active and leading role taken by the EU in both implementing and influencing IMO conventions.

147Four regional initiatives in this context are notable.

148The use of special areas in IMO conventions, the adoption of the Paris Memorandum of Understanding Mao on port state control, the development of the European Union shipping policy domain, and the emergence of market-based initiatives by ports and cargo owners.

149While plenty of local and international regulations have been introduced throughout maritime history, much of the current regulations are considered inadequate.

150In general, the treaties tend to emphasize the technical features of safety and pollution control measures without going to the root causes of substandard shipping, the absence of incentives for compliance and the lack of enforceability of measures.

151Where polycentric governance relies on positive relationships between major actors and conventions, one of the largest barriers to an effective environmental regulation of shipping arises from negative relationships between major actors and conventions, where ambiguous or overlapping jurisdictions result in a range of different issues such as a lack of effective enforcement and monitoring, inconsistent and unclear standards, and inadequate supervision resulting in blind spots in the high seas.

152Effective regulation of international shipping thus requires more international coordination.

153If states regulate emissions unilaterally, this leads to an overall increase in net emissions, whereas coordinated and uniform regulation between states reduces net emissions.

154However, varying patterns of governance are still seen across different ports with the same uniform regulation underscoring the need for policy to also take local and sectoral factors into account, perhaps through tailor-made adaptation measures.

155The effectiveness of uniform regulation also depends on the use of MRV and E-systems, which denote technologies, policies, and administrative processes that monitor, report, verify, and enforce compliance with the regulations.

156The current enforcement of regulations is lacking, and efforts need to be made to both strengthen supervision and law enforcement and establish a global monitoring system.

157The most common problems encountered with international shipping arise from paperwork errors and customs brokers not having the proper information about the items.

158Cruise ships, for example, are exempt from regulation under the U.S.

159Discharge Permit System, NPDES, under the Clean Water Act that requires compliance with technology-based standards.

160In the Caribbean, many ports lack proper waste disposal facilities, and many ships dump their waste at sea due to complexities of shipping trade and the difficulties involved in regulating this business.

161A comprehensive and generally acceptable regulatory framework on corporate responsibility for reducing GHG emissions is unlikely to be achieved soon.

162As in the case of negotiations around taxation of shipping fuels, international agreement around uniform regulation has not been reached, resulting instead in a deadlock.

163Overlaps of decision-making authority between central institutions can pose similar barriers if central norm conflicts between them are large enough, as in the case of competing principles guiding the United Nations Framework Convention on Climate Change, UNFCCC, and the IMO.

164The UNFCCC is guided by the Principle of Common but Differentiated Responsibilities, CBDR, which holds that since developed countries proportionally have contributed the most in terms of GHG emissions, they also take the largest responsibility for addressing the reduction of these emissions.

165The IMO, in contrast, is guided by Principles of Non-Discrimination and Equal Treatment and No More Favorable Treatment, NMFT, to all ships irrespective of their flag.

166This has led to a conflict between central interests since developed states support the NMFT principle while developing states support the CBDR principle.

167The effect of this conflict is that we are left with no clear principle around which to regulate resulting in impeding the legislation efficiency and consensus.

168A 2016 journal article recommends that under current circumstances, it is necessary for states, the shipping industry, and global organizations to explore and discuss market-based mechanisms, MBMs, for vessel-source GHG emissions reduction.

169MBMs are part of a broader category of mechanisms working through economic incentives that provide motivation for the adoption of less environmentally damaging practices, the second most common being infrastructure investments and informative policies.

170The most prominent and promising use of economic incentives are market-based measures, MBMs.

171The two main types of MBMs used are emission trading schemes and fuel levies.

172Both work through putting a price on GHG emissions providing economic incentives for taxed actors to improve their energy efficiency.

173However, these improvements are also accompanied by a short-term decline in industry profit.

174Some argue that the current use of MBMs in the EU emission trading scheme could serve as a window of opportunity to reduce GHG emissions in the shipping sector without placing an unnecessarily high burden on the shipping sector.

175The challenges standing in the way of this, the allocation of emissions, carbon leakage, permit allocation, treatment of the great variety in ship type, size and usage and transaction cost, are however hard to overcome without global market-based economies.

176Others' incentive-based schemes for achieving decarbonization include pricing schemes or the incentivization of front-runner ships that implement decarbonization technologies beyond regulations.

177However, evaluation of current the incentive schemes reveals that the schemes are onerous and only taken up by shipping enterprises or ports to a limited degree.

178Further, these incentive schemes are not specifically focused on a reduction in GHG emissions and thus do not support decarbonization.

179Further, these approaches are not without their critics.

180Lars Stemmler is critical towards the attitude that both environmental and social consequences of climate change can be mitigated through ever more efficiencies in shipping.

181Jason Monius similarly argues that the shipping sector generally operate by a business-as-usual logic based on assumptions of uninterrupted growth where actors must only address incremental challenges that can be adapted to in a piecemeal fashion.

182However, the consequences of climate change might instead take place on a disruptive and uncontrollable level, bringing starvation, destruction, migration disease and war, necessitating much more radical action.

183While Monius argues that the shipping industry has started to use the rhetoric of a logic of sustainability, the actions of shipping actors are still largely determined by the dominant business-as-usual logic, which block attempts at regulation from the IMO and leads to a loss of trust in and legitimacy of the system.

184Lastly, when MBMs become the primary means of addressing climate change at sea, Monius argues, this business-as-usual logic is strengthened, since they crowd out non-market norms and render invisible governance alternatives such as direct regulation and supply-side approaches.

185The list section issues by region is not included in this audio.

186This was the English Wikipedia article Environmental Impact of shipping as of December 4th, 2024, narrated by AI-generated voice via the open-source software Sony Translate.