Cruise Ships: Polluting Our Oceans?

Cruise ships are a source of significant pollution in the ocean, emitting large amounts of sulphur oxides, carbon emissions, sewage, and other waste into the water and air. They are also responsible for injuring and killing marine life and destroying coral reefs. With the cruise industry rapidly expanding, environmental laws and regulations have not kept pace, and new standards are urgently needed to address the pollution crisis caused by these ships. While some cruise ships have implemented eco-friendly practices, the majority continue to dump billions of gallons of waste into the ocean, contributing to the destruction of marine ecosystems.

Cruise ships dump sewage, food waste, and oily wastewater into the ocean

Cruise ships generate billions of gallons of waste that is pumped into the oceans every year, polluting the waters they travel through with a mix of toxic pollutants. While it is against US and international maritime law to release garbage directly into the water, cruise ships have been caught dumping sewage, food waste, and oily wastewater into the ocean.

Sewage from cruise ships can be pumped directly into the ocean without being treated in most places, as long as the ship is beyond three to three and a half miles from the shore. This leads to more than a billion gallons of sewage being pumped into the oceans annually. This sewage not only contains human waste but also includes chemicals, pharmaceuticals, bacteria, viruses, and heavy metals that are not naturally present in the ocean. The release of these toxic substances into the ocean can lead to reproductive problems, illness, and population decline in coastal animals, including otters, dolphins, and whales.

Food waste from cruise ships has also been linked to "dead zones" in the ocean, which are areas with a lack of oxygen due to rampant algae growth. This algae growth can be toxic to fish, turtles, birds, dolphins, and other marine life. It is estimated that around 30% of food on cruise ships is disposed of as "fish food" or liquified human food mixed with water. This waste often contains pesticides, chemicals, and growth hormones that are not natural for aquatic wildlife and can accumulate in animals at the bottom of the food chain, affecting the entire food chain.

Oily wastewater is another type of waste released by cruise ships. While there are regulations under MARPOL for the discharge of oily water, requiring it to be filtered through a separator to less than 15ppm before discharge outside of 12 miles, it still contributes to the pollution of the ocean. Cruise ships are also known for their air pollution, emitting large amounts of greenhouse gases and toxic pollutants such as carbon dioxide, sulfur oxides, nitrogen oxides, and particulate matter.

Cruise ships generate billions of gallons of waste that is pumped into oceans

Cruise ships generate billions of gallons of waste that is pumped into the oceans, causing significant pollution in oceanic and marine areas. This waste includes sewage, food waste, oily wastewater, greywater, scrubber discharge, and solid waste such as paper, cardboard, and aluminium. According to Friends of the Earth, more than a billion gallons of sewage are pumped into the oceans by cruise ships every year.

A large cruise ship with a capacity of 3,000 passengers can generate 150,000 to 210,000 gallons of sewage and 1 million gallons of greywater in just seven days. Greywater is water from sinks, baths, showers, laundry, and galleys, which can contain harmful pollutants such as detergents, oil, grease, heavy metals, and medical waste. Sewage and greywater are often released untreated, posing risks to marine life and ecosystems.

Cruise ships also contribute to air pollution through their emissions and incineration processes. A medium-sized cruise ship can use about 150 tons of fuel daily, emitting as much particulate matter as one million cars. The burning of fuel can release toxic substances such as polychlorinated biphenyls (PCBs), dioxins, and furans, which are hazardous to the environment and human health.

The impact of cruise ship pollution extends beyond the ocean, affecting the air, water, and land. It poses risks to fragile habitats and species, including whales and dolphins, and can have negative consequences for human health as well. With the cruise industry's rapid expansion, the environmental impact of these ships has become an increasingly pressing issue.

While some cruise lines claim to recycle or incinerate waste, the reality is that a significant portion of it is discharged into the ocean. Royal Caribbean, for example, states that it discharges food waste that has been pulverised and treated, but this still contributes to the vast amount of waste ending up in the sea. The cruise industry's environmental impact has prompted the creation of initiatives like the Friends of the Earth's Cruise Ship Report Card, which aims to hold cruise lines accountable for their actions and encourage eco-friendly practices.

Cruise ships' anchors damage coral reefs and their related organisms

Cruise ships have been criticised for their polluting impact on the oceans. They generate billions of gallons of waste, including sewage, food waste, and oily wastewater, which is often pumped directly into the ocean. Cruise ships are also responsible for air and noise pollution, as well as the destruction of coral reefs.

Coral reefs are crucial ecosystems that shelter one-fourth of marine species globally. However, the impact of cruise ships on these reefs is significant. One of the most visible and immediate effects is the physical destruction caused by the ships' anchors. When a cruise ship drops anchor in or near a reef area, the anchor's weight and drag can obliterate centuries of coral growth, crushing coral structures and disrupting the delicate balance of the ecosystem. This includes the destruction of coral communities and the uprooting of erect marine organisms such as sponges, gorgonians, and macroalgae.

The anchors of cruise ships can cause irreparable damage to coral reefs and their related organisms. The sheer size and weight of these anchors can lead to the destruction of coral structures and the displacement of marine life. In some cases, the anchor chains may also get entangled with the coral, further exacerbating the damage. The impact of a ship's anchor on a coral reef can be seen in a study where one cruise ship anchor destroyed 3150 square meters of previously intact reef in a single day.

To mitigate the impact of cruise ships on coral reefs, several measures can be implemented. Governments can play a crucial role by enforcing stricter regulations on waste disposal, emissions, and anchoring practices. Establishing and effectively managing marine protected areas (MPAs) can also help safeguard coral reefs from human activities, including anchoring. Additionally, cruise lines can adopt more sustainable practices, such as using alternative fuels, investing in advanced wastewater treatment technologies, and reducing their reliance on single-use plastics.

It is important to recognise that the impact of cruise ships on coral reefs extends beyond physical anchor damage. Cruise ships contribute to water pollution, which can weaken coral, making them more susceptible to bleaching. They also burn large amounts of heavy fuel oil, releasing significant greenhouse gases, such as carbon dioxide, which contributes to global warming and ocean acidification. These factors further exacerbate the fragile state of coral reefs and their associated organisms.

Cruise ships pollute the air with carbon emissions and sulphur oxides

Cruise ships are a major source of air pollution, particularly in relation to carbon emissions and sulphur oxides. Sulphur oxides, or sulphur dioxide, are released into the air and contribute to acid rain. They also cause respiratory and cardiovascular problems.

In Europe, 218 cruise ships emitted more than four times the amount of sulphur oxides than all of the continent's cars combined. Sulphur emissions in Venice, a city that was once Europe's third most polluted cruise port, decreased by 80% after a 2021 ban on large cruise ships. This highlights the impact of cruise ships on air quality and the effectiveness of regulations in reducing emissions.

Cruise ships are notorious for their high carbon emissions, with a single cruise ship emitting as much carbon dioxide as a million cars. The cruise industry has gained a reputation for contributing significantly to carbon emissions, with cruise ships being more carbon-intensive than short-haul flights. A week-long cruise can produce up to three times more carbon emissions than flying and staying in a hotel. On average, a cruise ship emits 250 grams of CO2 per passenger per kilometre travelled, and a trip can average between 700 and 1000 pounds of carbon emissions per day.

To reduce carbon emissions, some cruise ships have implemented energy-recovery systems that capture waste engine heat for steam cogeneration, desalination, and heating. By 2030, European cruise ships will also be required to connect to electric power sources when docked, reducing emissions from diesel fuel and liquid natural gas.

Cruise ships generate solid waste that forms debris on the ocean's surface

Food waste from cruise ships often contains pesticides, chemicals, and growth hormones that are not natural for aquatic wildlife and can accumulate in animals at the bottom of the food chain, affecting predators and other wildlife. It is estimated that a large cruise ship carrying 3,000 passengers and crew can generate 8 tons of solid waste in a week.

In addition to solid waste, cruise ships also produce sewage, wastewater, and hazardous waste. Sewage from cruise ships can be pumped directly into the ocean without treatment in most places as long as the ship is beyond 3.5 miles from shore. This leads to more than a billion gallons of sewage, containing human waste, chemicals, pharmaceuticals, bacteria, viruses, and heavy metals, being pumped into the oceans each year.

The increase in waste from cruise ships adds to the problem of pollution and oxygen depletion in the waters, with added nitrogen and phosphorus contributing to algae blooms that can suffocate coral reefs and marine life. Cruise ships also emit large amounts of greenhouse gases and toxic air pollution, with diesel generators releasing carbon dioxide, sulfur oxides, nitrogen oxides, and particulate matter into the air.

The impact of cruise ship pollution is far-reaching, and environmental laws have not kept pace with the growth of the industry. While some efforts have been made to address this issue, such as the EPA's study on cruise ship discharges and waste management, more urgent action is needed to protect our oceans and marine ecosystems.

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