Traveling on a cruise ship sounds like a great idea for a vacation. However, what seems like an exciting journey has a massive effect on our environment.
Cruise ships are some of the largest ships in the world, and studies have shown that one cruise ship releases a carbon footprint greater than 12000 cars3. Cruise ships are also a major source of pollution in the marine environment. But just how bad are they?
Read on as we examine the environmental impacts of cruise ships on our environment.
The cruise industry comprises businesses in the travel and tourism sector that facilitate voyages on large passenger ships. It involves cruise lines, cruise operators, and companies manufacturing cruise ships. The cruise industry also covers businesses that specialize in cruise entertainment.
A cruise line is a company that operates cruise ships and sells cruises to customers. This is distinct from passenger ships and passenger lines that link destinations. Cruise lines offer round trips primarily focusing on pleasure, while passenger ships focus on travel from one location to another.
Cruise lines provide various cruise packages, including accommodation, food, and entertainment. Some of the biggest cruise companies include Carnival Corporation (including brands like Princess Cruise lines, Costa Cruises, Holland America Line, etc.), Royal Caribbean International, MSC Cruises, and Disney Cruise lines.
Over the years, the cruise industry has grown, generating billions of dollars in revenue. However, the sector dipped during the global COVID-19 pandemic affecting tourism and the international shipping industry.
In 2022, the global cruise ship industry market was $7.67 billion and is expected to be worth $15.1 billion by 20284.
Millions of passengers every year board cruise liners all over the world. Although passenger numbers took a dip during the global pandemic, cruise lovers have come back on board.
However, the activities of the cruise industry have raised eyebrows among travelers and tourists. Many eco-conscious travelers wonder just how much cruise liners impact the environment.
Environmental groups have described cruise ships as “floating cities'' that contribute massively to pollution. Several cruise ships have been caught dumping trash, sewage, and fuel into the ocean.
Here are some major environmental impacts of cruise ships:
Findings reveal that on a seven-day trip, passengers on an Antarctic cruise can release as much carbon emissions per traveler as the average European in an entire year. These greenhouse gas emissions, predominately a product of burning fuel to keep the cruise ships moving and powered, get into the atmosphere, reducing air quality. High levels of air pollution can also affect human health.
Cruise liners accommodate thousands of passengers and crew members.
According to Friends of the Earth, the US Environmental Protection Agency estimates that a cruise ship of 3000 passengers and crew members generates about 21,000 gallons of sewage daily, an amount large enough to fill ten backyard swimming pools annually.
Whereas cruise liners typically treat sewage on board, in some cases, they may be allowed to discharge treated sewage into the ocean, provided they comply with the regulations and the discharge occurs at a safe distance from shore.
Furthermore, older ships may be equipped with lesser processing capability, with the Friends of the Earth's latest cruise ship report card scoring popular liners no higher than a “C.”
Sewage pollution can lead to infectious diseases and illnesses through contaminated water and seafood. Marine wildlife can also suffocate due to excess nitrogen and phosphorus from sewage entering the ocean.
According to research, a 3000-passenger ship can generate up to around 50 tons of solid waste in a week1.
These solid waste materials include plastic, paper, aluminum, and other debris. These solid waste materials can choke and kill marine wildlife if they enter the oceans.
Generally, throwing solid waste into the ocean is illegal. However, some ships have been caught dumping trash into the ocean. Also, some ships gather recyclable materials, while others burn non-recyclable materials, causing air pollution.
As these materials burn, they release harmful emissions like carbon dioxide, lead, and mercury, polluting the atmosphere and affecting human health.
More cruise ships on the sea mean more trouble for the animals underwater. Noises from moving ships travel as far as the ocean floors and reverberate back onto the surface. These vibrations affect the entire ecosystem of marine animals.
Findings suggest that cruise ship noises could affect the already endangered killer whales found near shipping lanes. Even a slight increase in sounds can make echolocation difficult for whales2.
Apart from a disruption in communication, noise pollution can also lead to a change in diving patterns, migrations, and panic responses.
Cruise ships also release chemicals from sewage and other channels, causing pollution. Toxic chemicals from daily operations, industrial products, and other substances find their way into the oceans, posing a threat to marine creatures.
Oils can also contribute to pollution. Cruise ships burn heavy fuel oils that contain harmful chemicals and substances like sulfur and heavy metals, which can leak into the oceans.
If a cruise ship has a faulty system or improper repair work, oils can leak from these areas and penetrate the oceans, causing pollution and threatening marine life.
Ballast water is essential for the safe operation of cruise liners. Ballast water helps to keep the ship floating in an upright and safe condition. It also gives the ship some stability as it maneuvers the oceans. However, while ballast water is crucial, it can also harm the environment.
Ballast water contains organisms like bacteria, eggs, microbes, small invertebrates, and other species.
As ships load and unload ballast water, these organisms get released into the local environment. The problem is that they can travel in the ship’s ballast to ecosystems where they might prove harmful. Under the right conditions, these organisms can flourish and threaten resident populations.
One example is the Zebra Mussels Invasion in the Great Lakes in Canada. These species are native to the Black and Caspian Seas in Europe but arrived in Canada due to a ship ballast water discharge. They proliferated, outnumbering local species like the native mussels. Feeding on the same food source, these introduced species disrupted the local food chain and hindered the growth and development of these local species.
The transfer of invasive species is one of the biggest threats to the ecological well-being of the planet. This is because it causes an imbalance in the coastal ecosystems.
Water from showers, sinks, laundry, cleaning utensils, etc., are all classified under grey water. Cruise ships release large amounts of grey water from regular activities like bathing and laundry.
Sadly, the accumulation of grey water contains harsh chemicals, metals, and other particles that can pollute the oceans. Through grey water, detergents, pharmaceuticals, microbeads, oils, etc., can find their way into the sea. Not only does this cause pollution, but the waste produced can also poison marine life.
Moreover, food waste from passengers, boats, and shipyard staff may also enter the ocean. Food waste contains chemicals unsuitable for the oceanic ecosystem and marine animals.
In 2018, a Holland America ship reportedly discharged 25,000 gallons of greywater into Glacier Bay National Park in Alaska and was hit with a fine of $17,000.
Cruise ships can be a significant threat to Coral reefs. Tourist vessels and anchoring of cruise ships on areas of coral reefs around the world have led to several destructive incidents.
In 2017, a British-owned cruise ship crashed into a coral reef, damaging approximately 13,500 square meters of coral reef in Indonesia.
Besides pollution and damage to our ecosystem, these large cruise liners can also threaten aquatic life. These ships are responsible for injuring marine animals. Also, solid waste like glass, plastic, etc., ends up in the digestive systems of these marine animals, leading to their death.
The cruise industry negatively impacts our water, air, coastal communities, and fragile habitats. Although various environmental regulations exist for cruise lines worldwide, compliance is only sometimes achieved.
Friends of the Earth, an environmental group, shared a Cruise Report Card, which took a controversial turn. The group gave each cruise line a grade from A-F based on these elements of sustainability:
Friends of the Earth also goes ahead to provide more specific information about the environmental impact of some of the top cruise lines in the world:
Carnival Corporation Cruise Line is one of the largest cruise companies, with ten cruise lines.
Unfortunately, Carnival Corporation is notorious for violating environmental regulations.
According to Friends of the Earth, this cruise line was hit with a fine of $40 million for illegal waste disposal and put on federal criminal probation.
Carnival Corporation was charged with dumping food and plastic waste in Bahamian Waters, illegally dumpling gallons of wastewater in the Glacier Bay National Park in Alaska, and releasing over 11,000 gallons of food waste and 500,000 gallons of sewage, among other charges.
Royal Caribbean is also one of the world's largest cruise companies and is notorious for paying criminal fines.
Findings from FOE state that this cruise company was forced to pay a fine of $18 million for 21 federal colonies in 1999. This was due to the dumping of waste oil and chemical waters in coastal waters.
Although this cruise company has cruise ships with scrubbers that help reduce air pollution and get around harmful greenhouse gas emissions, it is only a case of converting air pollution into water pollution.
Disney is one of the few cruise companies open about their environmental impact. The cruise line efficiently utilizes fuel with a 0.1% sulfur content, ultimately reducing its carbon footprint.
Unfortunately, Disney isn't perfect, either. The cruise company plans to work on a massive cruise ship port at Lighthouse Point in the Bahamas. Community groups within the region oppose this port as it will cause harm to their marine ecosystems.
The Bahamian Island of Eleuthera has over 200 bird species, four endemic plant species, beautiful clear blue water, lemon sharks, sea turtles, etc. The introduction of Lighthouse Point could bring many tourists and travelers, ultimately adding water, air, and noise pollution to this unscathed region.
MSC Cruises is part of the Hydrogen Council - a global initiative working toward the use of hydrogen fuel. The company has also launched the MSC World Europa ship, which LNG will power. The ship sails with less harmful emissions like carbon dioxide, sulfur oxide, etc. that result from heavy fuel oil.
However, MSC Cruises still has much to do to reduce its environmental footprint.
With 19 ships in its fleet, 15 use scrubbers that turn air pollution into water pollution, only 12 have advanced sewage treatment systems installed, six travel to ports with shoreside power, and only 8 of their ships have shoreside plug-in capability.
The cruise industry has had a negative environmental impact for many decades, putting human health, coastal communities, and our environment at risk.
Today, the cruise industry is making environmental efforts to reduce its carbon footprint and create a positive environmental change.
These include using Liquefied Natural Gas (LNG) ships, exhaust gas cleaning systems, and other new technologies. Here are some ways the cruise industry is going green:
Cruise ships release large amounts of harmful gas emissions, contributing significantly to air pollution and global warming.
Air pollutants like nitrogen oxide and sulfur from cruise ships pollute the air and contribute to respiratory problems. To reduce air pollution and improve air quality, cruise lines have turned to exhaust gas cleaning systems (EGCS).
Manufacturers designed the EGCS to reduce sulfur oxide and nitrogen levels. They remove these harmful gases from the ship's engine exhaust.
Also, The International Maritime Organization (IMO) 2020 established a regulation allowing only a sulfur content of only 0.5% in marine fuel to ships worldwide.
Cruise lines can meet this requirement by going for cleaner fuel alternatives like Liquified Natural Gas (LNG) or using EGCS (scrubbers).
However, some environmental groups have raised concerns about scrubbers that discharge wastewater back into the sea, turning air pollution into water pollution.
A large cruise ship can generate tons of waste, polluting our environment. Cruise liners have begun to reduce or ban the use of single-use plastics to reduce plastic waste.
Most ships have recycling bins that store solid waste materials like plastic, glass, and cardboard until they get to the next port and offload.
As we already know, the cruise industry has had major negative environmental and human health impacts. But it's not all doomsday for the cruise world.
Many shipping lines are now taking more significant steps toward more sustainable cruising. Some cruise operators now build ships that run on LNG. Also, some cruise shipping lines invest in greener fuels like hydrogen fuel cells and biofuels.
While the cruise travel industry has a long way to go, some cruise lines are working hard to make cruise travel significantly sustainable. Here are some eco-friendly cruise shipping lines leading the pack:
Hurtigruten is a Norwegian travel company that incorporates sustainability at its core. The company aims to have the world's first zero-emissions cruise ship by 2030. The company has since ditched unsustainable fuel sources for greener alternatives like biofuels and marine gas oil.
Hurtigruten launched the world's first hybrid battery electric-powered cruise ship in 2019 and aims to convert the seven ships of the Norwegian Coastal Express fleet to hybrid battery power or biofuels (which partly comes from dead fish).
The company also excels in single-use plastic reduction, as it has been scrapped from its operations altogether. They select their suppliers based on the merits of their sustainability.
On board, the company only serves food locally and sustainably sourced. In addition, crew members have uniforms made from recycled fishing nets.
Ponant is a French cruise shipping line that carbon offsets 100% of all its emissions. The 245-passenger Le Commandant Charcot, Ponant’s hybrid expedition ship, is one of the most eco-friendly ships, running on LNG and electric battery power.
The company has also stopped the use of single-use plastics. They take sustainable cruise tourism seriously and carefully plan all itineraries with local communities.
Ponant is also the first cruise company to get a Green Marine certification, which they award to companies that commit to minimizing their environmental impact.
Havila Voyages, a Norwegian cruise ship, has launched two of four of its planned hybrid ships in 2022, which use some of the biggest batteries combined with LNG fuel.
With this, the ships can travel for up to four hours on the sea without emissions or noise before recharging at the next port cities.
The company also recharges its batteries sustainably using clean hydropower energy from local grids. They also aim to run emission-free with vessels designed to switch entirely to hydrogen power as technology improves.
Ever thought of a cruise that operates on wind power? Star Clippers, a Monaco-based company, takes sustainability to a unique level with tall cruise ships that usually operate on wind power. At other times, their ships use low-sulfur gas oil.
Star Clippers is also one of the first cruise lines with a Pura Vida Pledge certification approved by the Costa Rican Tourism Board.
A large part of reducing the cruise industry's environmental impact starts with cruise lines keeping specific environmental standards. However, you can do your part as you vacation on the high seas by making small changes.
Here are some ways you can reduce your environmental impact while on a cruise:
Large amounts of harmful gas emissions and environmental pollution can be attributed to cruise ships. This is not to mention the waste produced by passengers and the cruise industry. All these activities from the cruise industry hurt our environment.
Many cruise lines claim to be taking steps towards more sustainable travel. However, not many of these cruise shipping lines are taking steps towards effecting any significant change.
Thanks to technological advancements, a few companies are leading the way to eco-friendly cruising. And given growing awareness, we're likely to see improvements to the environmental footprint cruise ships sailing around the world leave behind. In the future, we may even start to ee zero emission vessels.
Butt, Nickie. (2007). The impact of cruise ship generated waste on home ports and ports of call: A study of Southampton. Marine Policy. 31. 591-598. 10.1016/j.marpol.2007.03.002.
Veirs S, Veirs V, Wood JD. 2016. Ship noise extends to frequencies used for echolocation by endangered killer whales. PeerJ 4:e1657
Josep Lloret, Arnau Carreño, Hrvoje Carić, Joan San, Lora E. Fleming. Environmental and human health impacts of cruise tourism: A review. Marine Pollution Bulletin, 2021; 173: 112979 DOI: 10.1016/j.marpolbul.2021.112979
Cruise Market Size, Share & Growth Report, 2022-2028. (n.d.) Grand View Research
Jen’s a passionate environmentalist and sustainability expert. With a science degree from Babcock University Jen loves applying her research skills to craft editorial that connects with our global changemaker and readership audiences centered around topics including zero waste, sustainability, climate change, and biodiversity.
Elsewhere Jen’s interests include the role that future technology and data have in helping us solve some of the planet’s biggest challenges.