Stakeholders from the world of transport, accommodation, restaurants, and activities have signed a declaration committing to decarbonising by 2050. For cruise ships, which combine all of those areas into one, the challenges are very particular.
Holidays can be an enchanting escape from reality, and cruise tourism can be a particularly exciting adventure – a floating city that carries you to exotic locations. But it can also have big impacts on local environments if not managed correctly.
Cruise ships combine the impacts of hotels, transport, and entertainment into a single package, and the sector has grown fast since the pandemic pause. The cruise industry has been looking at ways to monitor and improve its sustainability performance.
The global cruise industry, including both ship operations and related activity, is estimated to account for around 0.6%-0.7% of total tourism-related CO₂ emissions according to MedCruise, an industry association representing over 160 ports and cruise destinations across the Mediterranean and its adjoining seas.
“Although this share is relatively small within the broader tourism system, the per-passenger footprint can be higher due to the energy demands of operating large vessels and providing hotel-level amenities at sea,” explains MedCruise president Theodora Riga. “It is also important to note that there is wide variation across the sector, as emissions depend heavily on factors such as ship size, itinerary, fuel type, distance travelled, and occupancy levels.”
Direct comparisons difficult
Direct comparisons with a flight show that purely as a mode of transport, cruise ships are more emissions-intensive. One recent overview by GreenMatch estimates that even relatively efficient large cruise ships emit around 250 g of CO₂ per passenger-kilometre, whereas typical air travel ranges from about 10-130 g CO₂ per passenger-kilometre, depending on aircraft and route. But of course, cruise ships aren’t a means of transport like an airplane.
Combining all the impacts of a holiday – the transport, accommodation, and activities – into one means direct emissions-intensity comparisons to the total emissions of a land-based holiday are difficult to calculate.
“Beyond CO₂, cruise operations involve other environmental aspects including air pollutants like SOx, NOx, and particulates, waste management, and water usage,” notes Riga. “Overall, while cruising remains a relatively small but visible segment of global tourism emissions, its growth trajectory means decarbonization is both a priority and a responsibility shared across the industry.”
Stakeholder declaration
Last year, the various elements of the European tourism sector signed up to a declaration committing to decarbonisation actions. The declaration, signed in Rhodes, Greece, by industry groups including the Cruise Lines International Association (CLIA), the hospitality association HotRec, Airports Council International, and attractions industry association IAAPA, reaffirms the sector goal of working toward decarbonisation by 2050, in line with the EU’s target.
“The travel and tourism industry is neither immune to, nor unaware of, the challenges posed by climate change,” they wrote. “Severe environmental impacts such as rising sea levels, extreme weather events, and habitat destruction threaten the very resources tourism relies on.”
Of course, what isn’t measured can’t be reduced. Certification schemes will be needed to show that progress is being made. The Global Sustainable Tourism Council is managing the global GSTC Standards for sustainable travel and tourism, as well as providing international accreditation for sustainable tourism certification bodies.
“An assessment consists of making objective ratings of compliance to all the elements of a standard,” explains GSTC CEO Randy Durband. “They are benchmarking tools and not marks. “A proper certification mark is one in which the assessment is made by an expert auditor with full impartiality by a 3rd-party agent.” For each element of the assessment, a tourism provider is deemed to be compliant or non-compliant.
Improvements to sustainability performance for cruise ships can be made through actions such as “improving ship design to include recycling facilities and first-level sewage treatment,” he notes.
“Those we work with are driving their land suppliers to use more clean energy vehicles and other improvements per our standard for tour operators. CLIA is providing some financial support to ports to conduct GSTC Destination Assessments in order to drive improvement.
It isn’t just voluntary industry commitments driving the change.
Durband says one of the biggest policy drivers that is driving improvement in Europe is the mandate that by 2030, all cruise ports must provide the capacity for ships to plug into the local electricity grid in order to shut down their engines while in port. This practice is known as “cold ironing”.
That is unique to the EU, and “there are no truly significant regulations for big ships outside the EU that we’re aware of,” he says. He also points to local policies, such as the Port of Amsterdam requirement that riverboats be certified green in order to discharge passengers in the city centre.
Improvements so far
Several large cruise lines have invested in LNG-powered ships. LNG can significantly reduce SOₓ, NOₓ, and particulate emissions compared with heavy fuel oil and can lower CO₂ emissions on a tank-to-wake basis.
However, LNG can suffer from methane slip, where unburnt methane escapes, and methane is a very potent greenhouse gas, which could undermine climate benefits. So proper installation and handling are essential. Companies and shipyards are also exploring bio-LNG, green methanol, and synthetic fuels, though these are still at pilot scale.
There are also design elements available to reduce emissions. These include optimised hull forms and low-friction coatings, high-efficiency propulsion and hotel systems, LED lighting, and smart HVAC. Route optimisation software can minimise fuel use. And in some cases, hybrid systems with batteries can handle peak loads or enable short zero-emission operation in sensitive areas.
Riga from MedCruise says that at the global level, the IMO’s Greenhouse Gas Strategy, revised in 2023, has helped guide the global industry toward a goal of net-zero GHG emissions by around 2050.
“The MARPOL Annex VI regulations on air pollution have also been transformative, particularly through the creation of Sulphur Emission Control Areas (SECAs), now extended to the Mediterranean, where sulphur content in fuels is limited to 0.1%,” she says. She notes that within Europe, the EU Emissions Trading System (ETS) has become “the single most impactful instrument”.
“Since January 2024, cruise ships calling at EU ports must purchase carbon allowances for their CO₂ emissions, 40% in 2024, rising to 100% by 2026. This represents a direct economic incentive for cruise lines to cut emissions through cleaner fuels, operational efficiency, and optimised itineraries,” she says.
Further action
In 2024, MedCruise conducted a study entitled “Sustainability Investments and Projects in the Mediterranean Ports”, analysing the implementation of environmental monitoring programs, OPS deployment, alternative fuels, pollution prevention and biodiversity protection. It finds a number of possible areas for future action, such as fuel-switching, net zero propulsion research and smarter itineraries.
The association has formed a strategic alliance with other European cruise associations – Cruise Baltic, Cruise Britain, Cruise Norway, and Cruise Europe – to coordinate best practices and harmonise environmental and tourism sustainability initiatives across Europe’s cruise destinations. They are also a partner in the EU-funded BlueMissionMed initiative, part of the EU Mission “Restore our Ocean and Waters by 2030,” which supports research, stakeholder engagement, and investment toward cleaner Mediterranean waters.
One of the most important factors is cooperation with the ports that cruise ships dock in, Riga says.
“Cruise sustainability ultimately depends on strong port and city collaboration, since the environmental and social effects of cruising are most visible at the local level,” she says.
MedCruise works with member ports, who in turn work closely with their municipalities and destination authorities to develop joint frameworks for emissions reduction, waste and water management, and visitor flow control.
“Many of our member ports co-invest with their cities in shore power systems, while others adopt fuel-switching policies or anchor restrictions to protect sensitive marine ecosystems such as Posidonia meadows,” notes Riga.
Sustainable tourism management is another key focus. “Together with local authorities, cruise ports and destinations have implemented measures to better manage passenger flows, including berth allocation, which manages the number of calls per day and adjusts scheduling to avoid peak times.”
Cruise lines have also been promoting alternative excursions that distribute visitors more evenly, and are looking into the development of low-impact experiences, such as walking or cycling tours and connections to nearby communities. “These destination-level collaborations demonstrate that sustainability is not only about technology but also about responsible management and respect for local communities,” she says.
The industry has made genuine steps, such as installing LNG, shore power, efficiency retrofits, and advanced wastewater treatment. But these steps risk being outpaced by growth in ship size and traffic. As the sector develops, it will be essential to continue efforts at developing cleaner fuels, better passenger management, and shore-side solutions.
(BM)
