While cruise ships account for only a small proportion of global shipping, they have a disproportionate impact on air quality, habitats and the climate. Cruise ships require more fuel due to the energy demand of the hotels and leisure facilities provided onboard as well as propelling the ships through the water. Cruise ships travel fast and close to the coastline, meaning that huge volumes of fuel are burned in close proximity to coastal populations.
Today cruise ships continue to burn dirty fuels which emit air pollutants such as SOx, NOx and particulate matter that have detrimental health effects, and result in greenhouse gas and black carbon (BC) emissions that accelerate global warming. Depending on where a cruise ship is going, it could be relying on a fuel whose sulphur content is 100 to 500 times higher than Europe’s sulphur standard for cars. In an attempt to reduce their environmental and/or climate impact, cruise ships have looked at potential solutions. But the most popular ones come with major drawbacks. For example, many cruise ships are equipped with an exhaust gas cleaning system – also known as a scrubber – which prevents sulphur from being emitted into the air, but results in contaminated water that can end up back into the oceans. Another increasingly popular alternative is to power cruise ships with liquefied natural gas (LNG) which decreases some of the air pollutants and CO2 emissions, but results in emissions of methane (CH4), a potent greenhouse gas whose global warming power is 82.5 times that of CO2 in the short term.
T&E’s study on cruise ships (June 2023) estimates that cruise ships sailing in European waters in 2022 emitted more than 8 million tonnes (Mt) of CO2 – the equivalent of 50,000 fights between Paris and New-York. When it comes to methane emissions, these appear to have been multiplied by five compared to 2019, establishing a clear trend favouring LNG. When it comes to the countries that are the most affected by cruise ships emissions such as SOx, Italy followed by Spain, Greece and Norway came on top of the ranking.