Are 'green' cruise ships good for the climate? (2024)

ByIsabelle Gerretsen,@izzygerretsen,

Are 'green' cruise ships good for the climate? (1)Are 'green' cruise ships good for the climate? (2)Getty Images

Many cruise companies are touting their green credentials. But can cruise ships ever be sustainable?

In January, the world's largest cruise ship set sail on its seven-day maiden voyage from the Port of Miami. The vessel, named Icon of the Seas, cost Royal Caribbean $2bn (£1.6bn) to build, has 18 decks, seven swimming pools and more than 40 restaurants, bars and lounges. It is 365m (1,195ft) long – 35m (115ft) longer than the Eiffel Tower and about five times as large as the Titanic.

The ship is powered by liquified natural gas (LNG) which Royal Caribbean has described as the "cleanest-burning marine fuel available". But environmental campaigners say LNG harms the climate because it leaks polluting methane into the atmosphere, which is about 80 times more potent than carbon dioxide (CO2) over a 20-year time span.

The industry's impact on the natural world is only set to grow as cruising booms. Ticket sales for cruise ships in 2024 have reached an all-time high. By the end of the year, 360 cruise ships are projected to have carried a total of 30 million passengers, a 9.2% increase compared to 2019, before Covid-19 hit.

"The problem is that the number of cruise ships keeps growing and the size of those cruise ships keeps growing as well," says Constance Dijkstra, shipping campaigner at the non-profit Transport & Environment. This will lead to more air and ocean pollution, she adds.

Many cruise companies have started touting their green credentials. But Dijkstra and other campaigners say that few are reducing their environmental footprint fast enough.

Cruise contamination

A large cruise ship can use up to 80,645 gallons (304,593 litres) of marine fuel per day, according to analysis by the University of Colorado Boulder. Marine fuels are variants of emissions-producing fossil fuels and therefore have a high carbon footprint.

Cruises are also a particularly carbon-intensive way to travel compared with many other types of holiday. The average CO2 emissions of a passenger on a cruise around Seattle are eight times higher than those of a tourist spending their holiday on land in Seattle, an analysis by the non-profit Friends of the Earth concluded.

And it's not just atmosphere-warming CO2 that's the problem. The 218 cruise ships operating in Europe in 2022 emitted more sulphur oxides (SOx) than one billion cars, or 4.4 times more than all the continent's cars, according to additional analysis by the non-profit Transport & Environment. SOx can harm trees by decreasing growth and contribute to acid rain which can damage sensitive ecosystems. Exposure to the pollutant can also harm the human respiratory system and cause breathing problems.

"We continue to caution people: 'If you're concerned about the environment, perhaps think about another kind of vacation,'" says Marcie Keever, director of the oceans and vessels programme at Friends of the Earth.

Are 'green' cruise ships good for the climate? (3)Are 'green' cruise ships good for the climate? (4)Getty Images

But is cruising worse than flying?

Even the most efficient cruise ships emit more CO2 per passenger kilometre than a passenger jet, according to analysis by the International Council on Clean Transportation (ICCT), a US-based non-profit.

Waste is another major problem. More than 31bn litres (8.5bn gallons) of toxic waste were discharged off the west coast of Canada by cruise ships travelling to and from Alaska in 2019.

Plus, noise pollution from ships harms marine life. A 2012 study found that mid-range noise from ships' sonar overlaps with blue whales' calls to each other, forcing them to repeat their vocalisations and disrupting their communication. (Read more about the surprisingly simple solutions to protect ocean life from man-made noise.)

Cleaning up cruising

Port cities are starting to crack down on cruise ships amid mounting health and environmental concerns. In 2021, Venice banned cruise ships from entering its historic centre, restricting them to the industrial port in response to a request from UN cultural body Unesco due to cruise pollution damaging historic buildings. Amsterdam and Barcelona have also banned cruise ships from their centres, in a bid to curb pollution and reduce overtourism.

"This is an industry that's flown under the radar when it comes to regulation," says Keever. "We're now seeing communities stand up to cruise ships and say 'the environmental pollution and the amount of passengers you're bringing here is too much.'"

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Cruise companies have started introducing measures to improve their sustainability record, such as switching to more energy-efficient appliances and engines, connecting to shore power while in port, running recycling schemes and reducing single-use plastic on board.

But it's the need to switch away from polluting fossil fuels that arguably poses the industry's largest challenge.

"To have a green cruise implies a change of fuel, which is very difficult," says Dijkstra. "It's great that cruise ships are promoting recycling or going plastic free, but if they're going to keep using fossil fuels, we're in trouble."

Are 'green' cruise ships good for the climate? (5)Are 'green' cruise ships good for the climate? (6)Getty Images

Many cruise companies have started running their ships on LNG, promoting it as the cleanest, at-scale alternative to polluting marine diesel. Between 2023 and 2028, 60% of new ships due to set sail will rely on LNG fuel for their primary propulsion, according to the Cruise Line International Association.

Carnival Corporation, one of the world's largest cruise operators, is relying on LNG to reduce its carbon footprint. The company aims to reduce its carbon intensity – the quanity of CO2 emitted per nautical mile – by 20% by 2030, compared to 2019 levels. It currently has nine LNG ships in operation, with orders placed for four more.

"There's a limit to how far we can go with efficiency measures," Vice Admiral Bill Burke, chief maritime officer at Carnival Corporation, tells the BBC. "We're probably in a situation where we're only going to get 20-30% of our overall emissions reduction [through efficiency measures].

"Ultimately, we need new fuels and right now the best fuel out there, that is readily available, is LNG."

But others disagree that LNG is the solution to cruise ships' climate problem. "LNG is not a transition fuel," says Keever. "It shouldn't even be part of the conversation."

While LNG ships emit about 25% less CO2 than conventional marine fuels, they have an additional harmful impact on the climate as they release methane, campaigners say. "Methane has a disastrous impact in terms of global warming," says Dijkstra. The greenhouse gas breaks down in the atmosphere in just 12 years, which is much faster than the centuries taken by CO2 – but methane is also about 80 times more powerful over a 20-year time span.

According to analysis by Transport & Environment, one of the UK's first LNG-powered cruise ships, P&O's Iona, emitted as much methane in 2022 as 10,500 cows over a year. A spokesperson for P&O told the BBC at the time that "LNG has much lower overall greenhouse gas emissions vs conventional fuels, even factoring in methane slip."

"Even with methane slip, the greenhouse gas footprint of LNG is better than marine fuel oil," says Burke. "It's the best fuel out there today."

Transport & Environment notes that no one knows the true extent of the methane emissions from LNG-powered ships, as the data is not available.

The race to replace gas

Whether or not LNG is an improvement on marine diesel, ultimately sustainable fuels that emit little to no greenhouse gases are needed to decarbonise shipping and meet the industry's 2050 net-zero goal, experts say. But which fuel can do this at scale remains up for debate.

Across the wider sector, companies are investing in hydrogen, methanol and ammonia as the shipping fuels of the future.

Container giant Maersk is relying on methanol to reach its 2040 net-zero target. Methanol can be a low-carbon fuel when produced from sustainable biomass or using renewable electricity to split water into oxygen and hydrogen, then combining it with CO2 to form methanol. It can cut CO2 emissions by up to 95% and nitrogen oxide emissions by up to 80%, according to the Methanol Institute, an industry body. Some argue that green methanol is not the right fuel to decarbonise shipping, however, as production is energy intensive and still results in CO2 emissions.

Another alternative is green ammonia, made by electrolysing water with renewable electricity. Analysis by the Environmental Change Institute at the University of Oxford found that green ammonia, which emits no CO2 when burned but does produce nitrous oxide emissions, could decarbonise 60% of global shipping when provided at just the top 10 regional fuel ports.

Are 'green' cruise ships good for the climate? (7)Are 'green' cruise ships good for the climate? (8)Getty Images

But the Cruise Lines International Association (CLIA), the trade body for the cruise industry, says that alternative fuels such as methanol and ammonia are not viable options.

"There are currently no sustainable alternative fuels available at scale to achieve [the cruise industry's] decarbonisation ambitions," says Andy Harmer, managing director of CLIA UK and Ireland. "CLIA is calling on governments to help accelerate the transition by setting more ambitious production targets, particularly for synthetic and biofuels."

Burke says that while methanol is the fuel that people often talk about, it's more expensive [than LNG and marine fuel] and not readily available. "There is no green methanol today," he adds, noting that most methanol is currently produced using natural gas, rather than renewable energy.

The process to produce green methanol is complex: CO2 must be captured out of the atmosphere, via technology which is still emerging, expensive and as yet unproven at scale.

However, the other green fuels on offer also spark other concerns. Ammonia is a highly toxic, corrosive and flammable fuel, according to the Global Maritime Forum, a non-profit based in Denmark. "Ammonia is toxic," Burke says. "It's not the best fuel for cruises – we've got 8,000 people on our ships, and many in our engine rooms."

To have a green cruise implies a change of fuel, which is very difficult – Constance Dijkstra

Dijkstra says many cruise companies say ammonia is unsafe to use on board ships carrying passengers. "But other companies are looking at that option…we are, for example, seeing DFDs ferries betting on ammonia," she says.

Keever says "it is feasible" for cruise ships to wean themselves off polluting fuels and switch to greener alternatives produced using renewable energy, such as methanol and ammonia, rather than fossil fuels.

"It's already happening in the larger shipping industry," says Keever, adding that Maersk, for example, is investing heavily in methanol. Transitioning to greener fuels "takes time and effort and a willingness to turn away from our dependence on fossil fuels," she adds.

Battery power

Norwegian cruise company Hurtigruten is focusing on a different technology to power its ships: batteries.

The cruise line company Hurtigruten aims to launch a zero-emissions cruise ship by 2030, which will be powered by 60MW batteries and huge, retractable solar sails, as part of its "sea zero" initiative (Read more: Will shipping return to its ancient roots?).

"We are using advanced battery and solar technology alongside old-fashioned tech: sails," says Hedda Felin, the company's chief executive. "We have sun 24 hours a day in the summer in Norway and it's very windy on the coast, so the ship is really tailored for the Norwegian coastline."

Are 'green' cruise ships good for the climate? (9)Are 'green' cruise ships good for the climate? (10)Getty Images

Four of Hurtigruten's fleet of nine cruise ships already have hybrid engines, which can run on both diesel and batteries.

"Hurtigruten are one of the leaders in the industry when it comes to adopting cleaner technologies, including [greener] fuels and advanced sewage treatment systems," says Keever. "And this is important because they go to places like the Arctic."

But there are limits to the distances batteries can power. The technology works well for Hurtigruten coastal cruises as "we are never more than six hours away from a port", says Felin. But it is not a practical solution for ocean cruise liners. "If we were crossing the Atlantic, batteries would definitely not be considered," says Felin.

Cruise companies visiting climate vulnerable locations, such as the Arctic, and bringing thousands of tourists to remote communities have a responsibility to operate more sustainably, says Felin.

"The cruise industry needs to take more responsibility…We are lagging behind massively," she says, adding that cruise companies have been slow to transition to cleaner alternatives.

But Felin says there is hope on the horizon; new technology and fuels will help power a more sustainable future for cruise ships. "There are several proven and safe choices for the future which mean we do not need to have fossil fuels on our cruise ships," she says. "That is the hope for the entire cruise industry."

The Royal Caribbean did not respond to the BBC's request for comment.

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Are 'green' cruise ships good for the climate? (2024)

FAQs

Are any cruise ships environmentally friendly? ›

Windstar Cruises: emphasizes sustainability through its use of natural propulsion, environmentally responsible waste management, and partnerships with organizations dedicated to ocean conservation.

What cruise line pollutes the most? ›

The most polluting cruise ships operator was MSC Cruises – whose cruise ships emitted nearly as much SOx as all the passenger vehicles in Europe. Accounting for all of its subsidiaries, the Carnival group polluted the most. Many cruise operators like MSC are investing in fossil gas (LNG) as a cleaner alternative.

What is the environmental impact rating of cruise ships? ›

U.S.-based NGO Friends of the Earth releases an annual scorecard that grades cruise ship companies on their environmental impacts. The most recent, from 2022, looked at 18 major cruise lines, giving the top overall grade, a C+, to a single company.

Which is worse for the environment cruise ships or planes? ›

Taking a seven-day cruise is more than three times as carbon-intensive as flying and staying abroad.

Which cruise line is most ethical? ›

The first cruise line to achieve Green Marine certification, Ponant also offsets 100% of its emissions. Plus, all Ponant ships are equipped with shore-to-ship power connections in port; the line has stopped using single-use plastics; and environmental impact studies are conducted before designing any itinerary.

What cruise line has the least problems? ›

The 15 cruise ships with perfect scores of 100
Cruise shipCruise lineScore
Carnival PanoramaCarnival Cruise Lines, Inc.100
Carnival SunshineCarnival Cruise Lines, Inc.100
Celebrity EdgeCelebrity Cruises100
Celebrity MillenniumCelebrity Cruises100
11 more rows
Jul 9, 2023

Are cruises the worst for the environment? ›

A five-night, 1,200-mile cruise results in about 1,100 lbs of CO2 emissions. In contrast, flying the same distance and staying in a hotel would emit a carbon footprint of 264kg of CO2 per person. Even a medium-sized cruise ship can have worse emissions than thousands of cars.

Are Alaskan cruises bad for the environment? ›

Reason for Concern

The two primary sources of water pollution from cruise ships in Alaska are treated wastewater (sewage/graywater) and exhaust gas scrubber wastewater. Each year, the size of cruise ships, the number of people they bring, and the voyages they take through Southeast Alaska increases.

How wasteful are cruise ships? ›

During a typical one-week voyage, a large cruise ship (with 3,000 passengers and crew) is estimated to generate 210,000 US gallons (790,000 L) of sewage; 1 million US gallons (3,800 m3) of graywater (wastewater from sinks, showers, and laundries); more than 130 US gallons (490 L) of hazardous wastes; 8 tons of solid ...

Is Royal Caribbean sustainable? ›

We design to build the most efficient ships possible, moving us closer to achieving Destination Net Zero, our vision for net-zero emissions by 2050. We equip our ships with technologies that allow them to operate efficiently today and give them the flexibility to adapt to new solutions as they become available.

Why are sailing ships said to be environmentally friendly? ›

Sailing is a very environmentally friendly form of transport as it harnesses the wind and sea without detriment to the environment. All Classic Sailing vessels maximise the use of sails, subject to safety and operational requirements.

How much CO2 does a cruise ship emit compared to cars? ›

More on pollution–poor cities. A recent research paper from the Marine Pollution Bulletin pointed out that a large cruise ship has a carbon footprint similar to 12,000 cars. The 2022 Cruise Ship Report Card painted an even grimmer picture.

How green are cruise ships? ›

The 218 cruise ships operating in Europe in 2022 emitted more sulphur oxides (SOx) than one billion cars, or 4.4 times more than all the continent's cars, according to additional analysis by the non-profit Transport & Environment.

Which cabin on a cruise ship is best to avoid seasickness? ›

To reduce motion sickness, choose a stateroom in the middle of the ship on a lower deck. You will feel any sway of the ship less in this section. Although it may seem counterintuitive, if you're worried about seasickness on a cruise, book a stateroom with a window or a veranda.

Will cruise ships go electric? ›

Hurtigruten, a Norway-based cruise company, first announced its plans to create a fully electric passenger vessel in early 2022. Now the company has released an actual prototype of the ship and more details on how it will operate when it launches in 2030.

Which cruise ships are emission free? ›

Hurtigruten, a Norwegian cruise line, is charting a course towards a greener future with plans to launch the world's first zero-emission cruise ship by 2030. This ambitious project, aptly named “Sea Zero,” is a beacon of innovation in sustainable maritime travel.

Do cruise ships still pollute the ocean? ›

On average, a cruise ship generates 15 gallons of toxic chemicals each day. These materials come from on-board dry cleaning and photo-processing facilities, painting and other activities. Seven thousand gallons of oily bilge water are released into the oceans every time the ship empties its bilge tanks.

Is Norwegian Cruise Line ethical? ›

It is Norwegian's strict policy to carry out all company activities in accordance with the letter and spirit of applicable legal requirements and to hold the highest possible standards of ethical business conduct.

Are Disney Cruises environmentally friendly? ›

Disney Cruise Line received the Vancouver Fraser Port Authority's 2023 Blue Circle Award for its participation in the port's voluntary EcoAction Program and Energy Action Initiative.

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