Which? analysis shows Disney and Norwegian top list of the most polluting European cruise lines
With huge amounts of energy consumed by cruise ships for air-conditioned cabins, restaurants and entertainment facilities, Which? found that in the worst cases some cruise ships have carbon emissions comparable to a small town.
Like all shipping companies, cruise operators visiting European ports must declare carbon dioxide emissions. Which? researchers analysed the EU’s 2023 monitoring, reporting and verification data to calculate which cruise lines were most polluting on average, based on average ship emissions per nautical miles travelled.
Rather than analysing total emissions – which would simply highlight the cruise lines with the most ships - analysing emissions per distance travelled spotlights the cruise companies operating the worst polluting vessels.Disney Cruise Line had just one ship in European waters last year, the 2,500 person capacity Disney Dream, but pumped out average Co2 emissions of almost one and half tonnes (1481kg) per nautical mile, putting it at the top of the table.
Norwegian had 10 ships in European waters and was the second-worst polluter based on average emissions per ship, with each vessel emitting an average of 1.4 tonnes (1413 kg) of Co2 per nautical mile.
The company is also home to the most polluting cruise ship in Europe, according to figures; the 4,100 capacity Norwegian Epic spewed two tonnes of CO2 for every nautical mile travelled. In total, this single ship was responsible for a shocking 95,000 tonnes (94,986,000 kg) of CO2 emissions in 2023 - as much as a town with around 20,000 residents (similar in size to Newmarket, Suffolk).Other cruise lines with high emissions included Princess Cruises with average emissions of 1253 kg per nautical mile, closely followed by Royal Caribbean with 1248 kg.
As demand for cruising grows - the Cruise Lines International Association predicts that 36 million people will take a cruise break this year - ships grow bigger, and with them the impact on the environment. Unsurprisingly, the 10 most-polluting cruise ships in 2023 were all mega ships carrying thousands of passengers. Three of these belonged to Norwegian.
The true scale of the problem is likely to be even bigger than highlighted in Which?’s analysis, as European ships will only have to start reporting methane emissions - a more potent global warming gas than carbon dioxide – next year. Which?’s ranking also doesn’t account for air and water pollution, which are currently too difficult to measure.
Air pollution close to the coastline also has an impact on health.The 45 cruise ships that called at Southampton port in 2022 emitted nearly nine times more polluting sulphur than all of the city’s 93,000 cars, according to Transport & Environment, a green think tank. Associated British Ports said they did not recognise the figure used.
Many holidaymakers are likely unaware of the true environmental cost of a cruise holiday. Separate analysis carried out on behalf of Which? by the carbon reduction consultancy Ecollective found the carbon footprint of a passenger on a European cruise can be larger than that of someone taking a short-haul holiday by plane.
This analysis found that a no-fly Mediterranean cruise emits five times more carbon dioxide equivalent (Co2e) per person than going to Barcelona by plane and staying in a hotel (2,100kg CO2e compared to 425kg CO2e). The carbon footprint of a two-week Caribbean cruise, including return flights to Barbados is more than double that of a two-week holiday in Barbados full board (6,196kg CO2e compared to 2,487kg CO2e).
Greenwashing can also make it harder for consumers to calculate the true environmental impact of a cruise holiday. There are multiple factors to take into account, and holidaymakers are likely to be confused by some cruise lines’ claims regarding exhaust gas cleaning systems, known as ‘scrubbers’, the use of liquid natural gas (LNG) and shore power*.
Nonetheless, some cruise lines are investing in genuine solutions, including electric batteries and hydrogen-derived fuels. Hurtigruten, a cruise operator based in Norway, has two ships that are partially battery powered, while Which? Recommended Provider Viking is currently building four ships that will be partially propelled by hydrogen fuel cells.
Naomi Leach, Deputy Editor of Which? Travel, said:
“Holidaymakers are becoming increasingly concerned about the impact of their travel both on the environment and on local communities. The emissions generated by some of Europe’s largest cruise ships are simply staggering.
“It’s clear more needs to be done to clean up the cruise industry and to tackle greenwashing to ensure consumers are getting clear and honest information about the impact of cruising.”
-ENDS-
Notes to editors:
Which? analysed Europe's most polluting cruise lines based on the EU's 2023 Monitoring, Reporting and Verification carbon emissions data, which was published in September 2024. This data is self-reported by cruise lines.
There are currently multiple methods available for analysing this data (for example, total overall emissions, emissions per distance travelled, emissions per transport network), and on advice from UCL Energy Institute, Which? opted to analyse emissions per nautical mile travelled as the fairest point of comparison.
The table (see below) uses the annual average CO2 emissions per distance travelled data and the average for each cruise line's fleet (for example if a cruise line had five cruise ships sailing to EEA ports in 2023, Which? calculated the average emissions across all five). Its analysis excludes ships that travelled fewer than 20,000 nautical miles because they did not do a full cruise season in Europe in 2023.
Norwegian Epic's emissions vs a small town's: Per capita carbon dioxide (CO₂) emissions in the United Kingdom were 4.7 metric tons in 2022 according to Statista. The size of a small town is 5,000 to 19,999 people according to the ONS. A small town with 19,999 people = 93,995 tonnes of CO2 vs Norwegian Epic's 95,000 tonnes. Built up area / town populations available here.
Carbon reduction consultancy Ecollective analysed the carbon footprint of various types of holiday on behalf of Which?. Graphic below:
*Scrubbers
Most cruise ships run on heavy fuel, one of the dirtiest and cheapest fossil fuels. Instead of switching to pricier, low-sulphur alternatives, many cruise companies use ‘scrubbers’ so that they can continue to use this tar-like, high-sulphur fuel while still meeting emissions regulations. Scrubbers are problematic as they use seawater to remove pollutants from exhaust emissions, and in the process, they turn air pollution into toxic water. Many cruise ships use an open-loop system that dumps the contaminated water overboard, harming marine life and disrupting eco-systems.
*Liquefied Natural Gas (LNG)
Even when cruise ships do use alternatives to heavy fuel, like liquified natural gas (LNG), the true environmental cost of these fuels is rarely made clear. For example, MSC Cruises recently ran an advert in more than 30 countries emphasising its commitment to sustainability. When Which? checked, its home page boasted that it uses “the cleanest marine fuel available at scale today” next to an advert for the MSC World Europa, one of its two ships able to run on LNG. However, while LNG does emit less CO2 than traditional marine fuels, it emits a significant amount of methane. Transport and Environment, a green thinktank, estimated that Europe’s LNG-powered cruise ships emitted as much methane as 62,000 cows in 2022, and according to experts, LNG can result in higher greenhouse gas emissions than an equivalent oil burning engine. Tristan Smith, reader in Energy and Shipping at UCL told Which?: “It is therefore incorrect to claim [LNG] is the cleanest marine fuel at scale today… there’s widespread recognition that LNG’s environmental credentials have been overstated and its use is an unhelpful distraction from the urgent transition that the shipping sector must make to become sustainable.”
*Shore Power
Some firms make eco-friendly claims about shore power which are likely to be overstated. Shore power, the ability to plug into shoreside electricity when in port, massively reduces emissions. Currently almost half of cruise ships are now capable of connecting to shoreside electricity, but only 2 per cent of the world’s ports offer it. Even where they do, it’s not necessarily used. In the UK for example, the only cruise port with a plug-in berth is Southampton – yet its owner, Associated British Ports, told Which? that just 50 cruise ships used it last year – around 10 per cent of those that visited.
Rights of reply:
Which? approached Virgin Voyages for comment but did not receive a response.
A Disney Cruise Line spokesperson said: “While we fully support transparency and accountability in emissions reporting, it is important to note that the methodology used in this analysis does not accurately reflect the full context of our operations, especially for a cruise line with only one ship operating in the region for a relatively short period of time.
“Disney Cruise Line complies with all air and water quality standards. While sailing in Europe, the Disney Dream used a combination of hydrotreated vegetable oil along with ultra-low-sulphur marine gas oil, which reduces greenhouse gas emissions beyond IMO requirements. DCL is committed to continuing to reduce its emissions in line with The Walt Disney Company’s environmental goals.”
Norwegian told Which? that while the EU’s MRV data can provide valuable insights, it’s only one piece of the full picture as it does not account for time spent in port, where emissions are naturally lower and where vessels spend a large amount of time or the number of passengers being transported on the ship, which it considers should be considered to reflect the ship’s efficiency per person.
It also told us that it is committed to reducing greenhouse gas emissions by 25% by 2030, using a 2019 baseline.
A Royal Caribbean Group (Royal Caribbean, Celebrity Cruises) spokesperson said: “Our mission is to deliver great vacations responsibly, and every day we are working with the best minds to advance our journey to net zero. LNG is one part of our decarbonization strategy. We view it as a transitional fuel that builds flexibility into our ship design and helps us adapt to different fuels as they become available. There is currently no silver bullet to reach our net zero target which is why we are diversifying our energy portfolio of energy sources by working with the best partners to accelerate the technology needed for maritime use, including biofuels, bio-LNG, and methanol.”
A spokesperson for Carnival Corporation & plc (P&O, Costa, Cunard, Princess and Carnival) said:
“Reducing greenhouse gas (GHG) emissions is Carnival Corporation & plc’s #1 sustainability priority and we are very proud of our progress so far in pursuing net zero emissions by 2050. Thanks to our aggressive climate actions, our fleet produces 10+% less total GHG emissions today than our peak historical year (2011), despite increasing capacity by ~30% during that time.
“GHG emissions based on distance sailed is not a good measure of the environmental performance of most cruise ships, which often sail shorter distances and spend significant time in port. A ship with high emissions-per-distance-sailed (like in your table) may actually produce less total emissions than a ship with low emissions-per-distance-sailed traveling further distances and using more fuel.
“Knowing the Which? organisation aims to inform consumer choice, we caution you against judging a ship’s environmental performance based on “emissions per mile.” Instead we recommend considering indicators that drive total emissions reductions, such as emissions per lower berth capacity. In fact, we’re on track to have cut our GHG emissions per lower berth capacity (called carbon intensity) by 40+% by 2026 (vs. 2008 levels), which is ahead of the IMO’s 2030 carbon intensity reduction timeline.
“Carnival Corporation & plc has a demonstrated multi-decade commitment to sustainable and responsible cruise operations detailed annually in our Sustainability Report. We invite you and your readers to check it out.”
A spokesperson for MSC Cruises said: “Irresponsible and biased reporting that relies on flawed methodology is doing more harm than good and is misleading consumers.
“The method used for this ranking is not an accurate reflection of the environmental performance of cruise ships and is misleading for consumers and does nothing to help them make informed decisions about the climate impact of their holiday. Those ships that spend the majority of their time travelling shorter distances and spending more time in port consume less fuel and therefore emit less emissions.
“In 2023, the number of shore power connections in Europe increased and we will see this continue to increase year on year, eliminating local emissions in ports where shore power is available. In 2023 we had two LNG ships operating in Europe and this sees a reduction of greenhouse emissions by up to 20% compared to conventional maritime fuels.
“We strongly dispute the claim that our ships have ‘high methane emissions’. Information regarding methane slip in the public domain and in this report is not scientifically accurate and often based on older generation LNG dual fuel engines and do not take into account the improvements that are being made in improved engine technologies and the resulting reduction in potential methane slip.
“Recent on board measurements on an LNG-fuelled MSC Cruises ship by independent third parties, as part of an EU funded project, have demonstrated that the latest type of engines operated on dual-fuel Liquefied Natural Gas vessels such as MSC Euribia release 40% less methane than the default values that are set by the EU rules. The results have been produced and presented in an academic research paper, demonstrating that the improvements in GHG emissions profile from LNG are up to 20% lower than conventional fuels.
“We stand by our position on the important role that LNG plays in the global energy transition and we acknowledge the urgency of the situation. Today, LNG provides not only an immediate improvement but will ensure our transition to bio-and synthetic renewable LNG fuels as they become available. In 2023, we sourced certified bio-LNG for the maiden voyage of MSC Euribia, allowing for a net zero emissions voyage. Replicating this success depends significantly on government strategies and fuel suppliers enabling the availability of renewable fuels suitable for the shipping industry.”
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