Boats' Impact: Air Pollution And The Marine Environment

Boats and ships are a major source of air pollution, which affects the health of communities in coastal and inland regions worldwide. The environmental impact of the shipping industry includes air pollution, water pollution, acoustic, and oil pollution. Ships are responsible for more than 18% of nitrogen oxides pollution and 3% of greenhouse gas emissions. Shipping vessels release more carbon dioxide into the air than most countries, and if shipping vessels were their own country, they would be the 6th largest carbon dioxide-contributing country. The large amounts of ballast water used by cruise ships, large tankers, and bulk cargo carriers are often discharged in coastal waters, causing ecological damage and contributing to marine pollution.

Shipping vessels emit more carbon dioxide than most countries

The combustion of heavy fuel oil and other fossil fuels by ships releases harmful gases, including carbon dioxide, methane, and nitrous oxide, contributing to climate change. The maritime transportation industry's carbon footprint is projected to surge by 50% to 250% by 2050 if proactive measures are not implemented.

To address this issue, the International Maritime Organization has set targets for net-zero greenhouse gas emissions for international shipping by 2050, with interim goals of a 20% reduction by 2030 and 70% by 2040. The industry can achieve these goals by improving energy efficiency and transitioning to low-emission fuels.

Additionally, the European Parliament has endorsed changes to include all maritime emissions in the EU Emissions Trading System (ETS). This expansion applies to ships over 5,000 gross tonnage operating within the European Economic Area. As a result, companies with vessels engaged in EEA trade must submit emission allowances equivalent to their greenhouse gas emissions during a given year.

Furthermore, new rules agreed by the International Maritime Organization will require shipping companies to pay for the carbon dioxide produced by their vessels for the first time starting in 2028. While the expected revenue of $10 billion per year falls short of the desired amount, it is hoped that the funds will be used to adopt cleaner technologies and reduce emissions.

Marine diesel engines produce harmful gases like nitrogen oxide and carbon monoxide

Marine diesel engines are a significant source of air pollution. They burn high-sulfur content fuel oil, also known as bunker oil, which produces sulfur dioxide, nitrogen oxide, and particulate matter. Nitrogen oxide emissions are primarily a function of combustion temperature; as air contains over 70% nitrogen by volume, some of it will react with oxygen during combustion. The higher the combustion temperature, the more nitrous oxide is produced. Marine diesel engines also produce carbon monoxide, carbon dioxide, and hydrocarbons, which contribute to the formation of aerosols and secondary chemical reactions in the atmosphere, such as the formation of HCHO and ozone.

The US Environmental Protection Agency (EPA) has classified diesel exhaust as a likely human carcinogen. The agency also recognizes that emissions from marine diesel engines contribute to ozone and carbon monoxide nonattainment, meaning they fail to meet air quality standards. These emissions have adverse health effects, including those associated with ambient concentrations of particulate matter and visibility, haze, acid deposition, and eutrophication and nitrification of water.

Shipping vessels are responsible for more than 18% of nitrogen oxides pollution and 3% of greenhouse gas emissions. If shipping vessels were a country, they would be the sixth-largest carbon dioxide-contributing entity. The large container ships have engines with up to 109,000 horsepower that weigh 2,300 tons and operate 24 hours a day for about 280 days a year.

The health risks of shipping pollution have been underestimated, with research showing that one giant container ship can emit almost the same amount of cancer and asthma-causing chemicals as 50 million cars. Low-grade ship bunker fuel can have up to 2,000 times the sulfur content of diesel fuel used in US and European automobiles. This has led to pressure on organizations like the UN's International Maritime Organization and the EU to tighten laws governing ship emissions.

Boat maintenance chemicals, like antifreeze, can leak and pollute water bodies

Boat owners often invest a lot of time and money into keeping their vessels in good condition. This can involve the use of various cleaning agents and chemicals, which can be a major source of water pollution. Boat maintenance chemicals, like antifreeze, can leak and pollute water bodies. Antifreeze is necessary for winter storage, and while it is designed to be non-toxic, excessive use can create leaks or spills that pollute the ocean or other water bodies.

Boat owners should be mindful of the environmental impact of their maintenance practices and choose products carefully. For example, antifouling paint used on the hulls of boats can contain toxic metals that are harmful to marine life. Similarly, oil spill disbursers or agents used to break down grease can contain solvents and strong acids, which can be detrimental to the environment.

It is important to note that repair work, such as sanding, filling, and painting, should ideally be done when the boat is stored on land. This way, any dirt, dust, or chemicals will be spilled on land surfaces and can be collected for proper disposal, reducing the risk of water contamination. Many marinas have systems in place to collect dust and paint scrapings to minimize their release into the environment.

However, if repair work must be done on the water, extra care should be taken to reduce impacts on the water body. Drilling, cutting, and sanding fiberglass can generate small particles of material that contribute to microplastic pollution in the oceans, which is a significant concern for wildlife and ecological health.

By being mindful of the products used and following best practices for boat maintenance, owners can help reduce the environmental impact of their vessels and protect water bodies from pollution.

Ships' ballast water discharge can negatively impact marine life

Ships require ballast water to stabilise the boat while travelling. However, ballast water discharge can negatively impact marine life in several ways. Firstly, ballast water often contains a variety of biological materials, including plants, animals, viruses, bacteria, microbes, small invertebrates, eggs, cysts, and larvae of various species. These materials may include non-native, exotic, and invasive species that can cause extensive ecological, economic, and human health issues. For example, a form of cholera (Vibrio cholerae) previously found only in Bangladesh, arrived in Peru via ballast water in 1991, killing over 10,000 people in three years. Similarly, the zebra mussel, native to the Caspian and Black Seas, was accidentally introduced to Lake St. Clair in 1988 through ballast water, spreading to the neighbouring Great Lakes within a decade and incurring an estimated economic cost of $5 billion.

The introduction of invasive species through ballast water discharge is a leading cause of environmental and economic damage in the marine ecosystem. These species can outcompete native species, leading to pest proportions and causing significant changes in the host environment. The transfer of invasive species through ballast water has been recognised as an issue since the 1970s, with countries like Canada and Australia experiencing particular problems in the 1980s. To address this, the International Maritime Organization (IMO) adopted the "International Convention for the Control and Management of Ships' Ballast Water and Sediments" in 2004, requiring ships to implement ballast water management plans.

Additionally, ballast water management itself can have unintended consequences. While on-dock ballast water treatment methods like chlorination, oxidation, and ozonation are effective in controlling invasive species, they can lead to the release of toxic disinfection by-products (DBPs) such as tri-halo methane and haloacetic acid. Furthermore, ballast water exchange standards aim for a 95% volumetric exchange of ballast water, but the remaining 5% can still contain organisms that impact marine life.

The environmental impact of ballast water discharge is significant, and regulations like the Ballast Water Management Convention and national regulations aim to minimise this impact. However, the complex nature of the issue, as highlighted by the National Research Council's 2011 study, underscores the need for continuous improvement in ballast water discharge standards and management.

Cruise ships produce noise pollution, which harms marine animals

Marine wildlife has been exposed to pollution from cruise ships for over a century. However, as time goes on, the pollution is becoming more intense. The oceans are getting louder, and marine animals cannot escape the noise.

Cruise ships produce noise pollution from their machinery and onboard entertainment activities. These noises disturb marine animals and mammals, including whales, dolphins, and killer whales, whose sensitive hearing gets harmed and debilitated. This often leads to their death and an overall loss to the ecosystem. Whale calls, for example, have become much louder due to ship noise, as they have to yell to be heard. This human-caused noise has already been linked to impacts on marine life, including disrupted behaviours, impaired feeding, increased stress, and masked communication. Marine animals' regular communication is disrupted by underwater noise pollution, making it difficult for them to call their mates, look for food, or even cry for help.

Studies have shown that while these noises may have no impact on humans, they can be detrimental to marine life. The population of cetaceans (whales and dolphins) has declined in areas prone to noise pollution from ships. The death of marine animals can occur hours after exposure to extreme underwater noise. For example, whales can die from strandings, and tactical sonar exercises have been linked to mass strandings in several regions.

Noise pollution from cruise ships also impacts the sonar of animals that rely on it, such as whales and dolphins. As a result, these animals may become disoriented and relocate to new regions, struggling to find mates or food and ending up hurt or dead.

Frequently asked questions