Cruise Ship Pollution: Marine Life Under Threat

Cruise ships have been a source of fascination for many, with their opulence and luxury attracting millions of travellers each year. However, beneath this glamorous facade lies a darker truth: the significant environmental impact of these floating cities. From sewage and wastewater to air and water pollution, cruise ships leave a trail of toxins in their wake, endangering marine life and ecosystems.

The cruise industry, with its massive vessels, contributes heavily to global pollution and climate change. A typical cruise ship generates enormous amounts of sewage, wastewater, solid waste, oily bilge water, and air pollution. The release of these wastes into the ocean can have detrimental effects on marine wildlife, including dolphins, fish, and coral reefs. Solid waste, such as plastic and glass, can choke or destroy the digestive systems of sea turtles and fish. Noise pollution from ships' machinery and entertainment activities also impacts whales and dolphins, interfering with their behaviour and, in some cases, leading to death.

In recent years, there has been growing awareness and criticism of the cruise industry's unsustainable practices. While the industry claims to be adopting more sustainable measures, critics argue that more needs to be done to address the global impact on the ocean, air, and fragile habitats. With the cruise industry continuing to grow and ships becoming larger, the environmental challenges are becoming more significant.

This issue has sparked concerns among environmentalists, industry stakeholders, and tourists, leading to discussions about the sustainability of cruise ships and the need for stricter regulations to protect our oceans and marine life.

Sewage and wastewater dumping

In the United States, cruise ships are allowed to dump treated sewage within three and a half miles of the shore. Beyond this limit, there are no restrictions on dumping untreated sewage. This means that a significant amount of untreated human waste, along with other pollutants, is released directly into the ocean. This adds to the problem of pollution and oxygen depletion in the waters. The increased levels of nitrogen and phosphorus contribute to the growth of algae blooms, which can suffocate and harm marine life such as coral reefs, manatees, shellfish, and fish.

Cruise ships also generate a large volume of greywater, which refers to water from sinks, showers, laundry, and galleys. This greywater is often discharged into the ocean, adding to the pollution load. Additionally, food waste is also ground up, mixed with water, and pumped out of the ship while at sea. This liquified food waste, referred to as "fish food" by the cruise industry, contains pesticides, antibiotics, and hormones, which are not part of a fish's natural diet. The accumulation of these chemicals in the ocean can lead to bioaccumulation, impacting both fish and other wildlife in the marine ecosystem.

The impact of sewage and wastewater dumping from cruise ships extends beyond the direct release of pollutants. The treatment process for sewage can also introduce chemicals that harm the reproductive systems of marine animals. Furthermore, the lack of proper sewage treatment facilities on many cruise ships means that toxins are not adequately filtered out before discharge, further exacerbating the problem.

The sewage and wastewater crisis caused by cruise ships is a significant concern for the health and sustainability of marine life. It is essential to advocate for stricter laws and regulations to hold the cruise industry accountable and protect our oceans and the valuable marine life that depends on them.

Air pollution

Sulfur Oxide Emissions

Sulfur oxide emissions, also known as SOx, are a significant contributor to air pollution and acid rain. Cruise ships emit large amounts of SOx, with Europe's 218 cruise ships emitting as much SOx as 1 billion cars in 2022. The Carnival Corporation's cruise liners alone emitted nearly 10 times more SOx air pollution around European coasts than all of Europe's cars. This has led to increased air pollution in port cities, surpassing pre-pandemic levels.

Nitrogen Oxide Emissions

Nitrogen oxide emissions, or NOx, released by cruise ships affect both the environment and human well-being. Cruise ships accounted for 15% of the nitrogen oxide particles emitted by Europe's passenger vehicles. In cities like Marseille, cruise ship NOx emissions were nearly equivalent to those of a quarter of the city's passenger cars.

Carbon Emissions

Cruise ships are known for their high carbon emissions, with a medium-sized cruise ship emitting around 250 grams of CO2 per passenger per kilometre. This is significantly higher than the carbon intensity of air travel, which ranges from 10 to 130 grams of CO2 per passenger per kilometre. On average, a cruise ship emits 250g of CO2 per passenger kilometre travelled, and a person on a cruise ship emits about 421.43 kilograms of CO2 daily, eight times more than someone on a land-based vacation.

Black Carbon

Cruise ships contribute disproportionately to black carbon emissions, which can exacerbate climate change, especially in the Arctic region. Despite making up only 1% of the global fleet, cruise ships account for 6% of black carbon emissions.

Heavy Metals

Cruise ships can release heavy metals into the environment, which are toxic to marine life and pose risks to human health.

Methane

Some cruise ships that use liquefied natural gas (LNG) as fuel emit methane, a potent greenhouse gas, due to "methane slipping" from their engines. This has raised concerns among environmental experts, who criticise LNG usage as a misleading solution to climate issues.

Other Air Pollutants

Cruise ships also generate various other air pollutants, including hydrocarbons, chlorinated hydrocarbons, volatile organic compounds, ozone-depleting substances, and particulate matter. The exhaust from cruise ship engines contains toxic air pollutants similar to those emitted by vehicle exhaust tanks on roads.

To address these air pollution issues, some jurisdictions have tightened rules and regulations. For example, Amsterdam recently joined cities like Venice, Italy, Monterey Bay in California, and Bar Harbor in Maine in regulating against huge cruise ships to tackle pollution. Additionally, Transport Canada upgraded measures to prohibit ship wastewater disposal in its national waters, which were previously likened to a "toilet bowl" due to lax regulations.

Solid waste

Cruise ships are responsible for 24% of the total solid waste generated by maritime traffic worldwide. The impact of solid waste from cruise ships is particularly harmful as it is often released in specific coastal areas and the same ports, leading to a cumulative effect on a local scale. The solid waste generated by cruise ships can also contain toxic chemicals used in daily operations, such as dry cleaning and industrial products, further endangering marine life.

To address the issue of solid waste pollution from cruise ships, some states in the US, such as California, Alaska, and Maine, have enacted laws to regulate or prohibit solid waste discharges. Additionally, environmental groups have advocated for stricter standards and more effective enforcement of existing regulations. Some cruise lines have also voluntarily adopted waste management guidelines and procedures to improve their environmental performance.

Noise pollution

Ocean noise, or anthropogenic noise pollution, is caused by human activities such as shipping, seismic surveys, explosions, construction, and sonar devices. These sounds act as stressors to the marine ecosystem, impacting the behaviour, physiology, and reproduction cycles of marine mammals. The problem is exacerbated by the fact that sound waves travel faster and farther in water than in air, and marine life is extremely sensitive to sound, even low-frequency noise that is inaudible to humans.

Cruise ships, in particular, contribute heavily to marine noise pollution. The windows on cruise ships allow more noise to escape into the ocean, and the entertainment activities on board create additional noise. This noise disturbs and harms the sensitive hearing of marine animals, including killer whales and dolphins, and can lead to their death and an overall loss to the ecosystem.

The impact of noise pollution on marine life has been documented in several studies. For example, noise from naval sonar devices has been linked to mass strandings of beaked whales, and increased ship noise has caused bottlenose dolphins to simplify their vocal calls, potentially reducing the effectiveness of their communication. In addition, animals in remote places may be at higher risk of complications from noise pollution as they are not accustomed to it.

To mitigate the impact of noise pollution on marine life, several measures have been proposed and implemented. Some cruise lines have developed protocols for sensitive areas, including reducing speed and refraining from making announcements on outside decks. There are also efforts to develop quieter technologies, such as using propellers to reduce cavitation and electric motors to decrease noise levels. Policies and regulations to reduce propeller noise and limit the use of sonar equipment are also necessary to protect marine life from the harmful effects of noise pollution.

Oil pollution

Cruise ships are responsible for accidental oil spills, which can cause significant harm to marine life and the environment. A study published in the Journal of Marine Pollution Bulletin found that cruise ships have the potential to contribute to accidental oil spills due to their large size and the amount of fuel they carry. In Ha Long Bay, Vietnam, oil spills from sunken cruise boats were responsible for more than 60% of biodiesel and petroleum diesel spills in the area.

The direct discharge of untreated oily bilge water from cruise ships can also damage marine life and ecosystems. If the separator used to extract oil is faulty or deliberately bypassed, untreated oily water can be released directly into the ocean. This oily bilge water mixes with oceanic water and causes marine pollution. Faulty engine systems, improper repair work, and collisions or accidents are all potential sources of oil leaks that can lead to oil pollution.

The impact of oil spills from cruise ships can be devastating to marine life and the environment. Oil spills can harm marine mammals, fish, birds, and coastal habitats and beaches. A study published in the Journal of Environmental Science and Pollution Research found that oil spills can cause both short-term and long-term damage to marine ecosystems.

To prevent oil spills and mitigate their environmental impact, proper regulations and management are essential. Alaska's Commercial Passenger Vessel Compliance Program has been cited as a model for other states to follow, with its strict regulations for cruise ships to prevent oil spills and protect the environment.

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