The world’s largest cruise ships emitted as much carbon dioxide as a small town last year.
The energy consumption of these mega-ships – which power air-conditioned cabins, restaurants and entertainment facilities – can lead to carbon emissions on par with a small town.
As all shipping companies visiting European ports are required to declare their carbon dioxide emissions, consumer magazine Which? was able to analyse the EU’s 2023 monitoring, reporting and verification data to determine which cruise lines were the most polluting on average, based on ship emissions per nautical mile travelled.
Rather than looking at total emissions, which would simply highlight the cruise lines with the most ships, the analysis focused on emissions per distance travelled to identify the worst polluting vessels. Disney Cruise Line, despite having only one ship in European waters last year – the 2,500 person capacity Disney Dream – topped the table with average CO2 emissions of almost one and half tonnes (1,481kg) per nautical mile.
Norwegian, with 10 ships in European waters, 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 also boasts the most polluting cruise ship in Europe, according to data. The Norwegian Epic, with a capacity of 4,100, emitted two tonnes of CO2 for every nautical mile it travelled.
In total, this single vessel was responsible for an astounding 95,000 tonnes (94,986,000 kg) of CO2 emissions in 2023 – equivalent to a town of around 20,000 residents, similar to Newmarket, Suffolk. Other high-emission cruise lines included Princess Cruises, with average emissions of 1253 kg per nautical mile, closely followed by Royal Caribbean at 1248 kg.
As the popularity of cruises increases – the Cruise Lines International Association predicts that 36 million people will take a cruise holiday this year – ships are getting larger, and so is their environmental impact. Notably, the 10 most-polluting cruise ships in 2023 were all mega-ships carrying thousands of passengers, three of which belonged to Norwegian.
European ships will only begin reporting methane emissions next year. It is a more potent global warming gas than carbon dioxide. Which’s ranking also doesn’t account for air and water pollution, which are currently too difficult to measure.
Air pollution near the coast can also have serious health implications. According to Transport & Environment, a green think tank, the 45 cruise ships that docked at Southampton port in 2022 spewed out nearly nine times more sulphur pollutants than all of the city’s 93,000 cars combined.
Associated British Ports, however, disputed this figure. Many holidaymakers may not realise the true environmental impact of their cruise holidays. A separate study conducted by carbon reduction consultancy Ecollective on behalf of Which? revealed that a passenger on a European cruise could have a larger carbon footprint than someone taking a short-haul plane holiday.
The study found that a no-fly Mediterranean cruise emits five times more carbon dioxide equivalent (Co2e) per person than flying to Barcelona 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 full-board holiday in Barbados (6,196kg CO2e compared to 2,487kg CO2e). Greenwashing can make it difficult for consumers to accurately assess the true environmental impact of their cruise holidays.
There are many factors to consider, and some cruise lines’ claims about exhaust gas cleaning systems, known as ‘scrubbers’, the use of liquid natural gas (LNG) and shore power* may confuse holidaymakers.
Hurtigruten, the Norwegian cruise operator, is leading the way with innovation on the seas, boasting two vessels that sail with partial battery power. Moreover, Viking is making waves with the construction of four hydrogen fuel cell-powered ships.
The analysis does not include ships that sailed less than 20,000 nautical miles as they did not complete a full cruise season in Europe in 2023.
Biggest polluting European cruise lines
(Cruise line, 2023 cruise line average CO2 emissions per distance [kg CO2/n mile], number of ships)
- Disney Cruise Line: 1481, 1
- Norwegian Cruise Line: 1413, 10
- Princess Cruises: 1253, 4
- Royal Caribbean: 1248, 7
- MSC Cruises: 1229, 19
- Virgin Voyages: 1229, 2
- Celebrity Cruises: 1228, 7
- Cunard: 1207, 2
- P&O Cruises: 1108, 7
- Costa Cruises: 1051, 9
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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.”
A spokesperson for Norwegian said 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. The spokesperson said that it is committed to reducing greenhouse gas emissions by 25% by 2030, using a 2019 baseline.
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.”