Cruise ships pump out 10 times the CO2 per passenger as flying. Can they turn the tide?

Indoor waterfalls, endless buffets, jacuzzis against an Arctic backdrop: these are the things that make cruises as outlandish as they are appealing. Cruises have bounced back incredibly since the pandemic: 31.7 million people took one in 2023, a 7% rise increase on 2019’s figures. But the scale of their recovery doesn’t seem very eco-friendly. To accommodate more passengers, cruise ships are getting bigger and more extravagant. So can cruising also ride the wave of sustainability into the future, or are its current green attempts not enough to stay afloat?

Ten to one

A cruise trip generates far more carbon emissions than alternatives like flying or driving. While a passenger on a plane will produce an average of 25g of CO2 per kilometre, the most efficient cruise ship will produce 250g over the same distance, or 10 times as much.

In order to reduce this enormous amount, many of the larger cruise lines have adopted a renewable fuel called liquefied natural gas (LNG). An eco-friendlier approach than traditional heavy fuel or marine diesel oil, LNG can make ships of all sizes more efficient, but not carbon neutral.

“Switching to cleaner fuels is a good start, but while that means ships don’t make extra carbon, it’s not offsetting what they’ve already produced,” says local guide Wayne Kask from West Florida, one of the regions most affected by cruise traffic.

“Cruising needs to pick up the tempo of change significantly, and start considering bolder green solutions, including protecting fragile destinations,” he adds.

Carbon emissions are just the tip of the iceberg. Additional challenges include coastal and reef erosion, air pollution, ‘grey water’ sewage (water from sinks, washing machines etc) dumped in the sea and food waste generated on board.

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A cruise ship report card put together by environmental network Friends of the Earth rated the top 20 cruise lines against those criteria and found none of them achieved above a C+ grade.

“From a zero-carbon perspective, there is a long way to go before cruises can be fully sustainable, and it often depends on how fast technology is advancing”, says Mike Penrose, former director of Unicef UK and co-founder of ESG management company FuturePlus.

“Carbon neutrality won’t happen overnight. But in the meantime, there is a real opportunity for cruise lines to improve in other aspects of sustainability, including supply chain and social impact, that can happen now.”

Cruise control

At one time, a cruise ship dropping anchor in a small island was believed to boost the local economy and have a positive impact. But the reality is very different.

Cruising is one of the two biggest culprits of overtourism in the 21st century, according to Elizabeth Becker, travel expert and award-winning author of Overbooked: The Exploding Business of Travel and Tourism.

“When the ship lets the flood of people on shore, they’ve already done all their eating and sleeping on board. They only get a couple of hours at most to spend in the destination so they don’t end up contributing much to the local economy,” she says.

With all their needs met on board, passengers can cause a negative impact on destinations when “the money spent cleaning after them massively outweighs what people spend on the odd coffee there,” Becker says.

The adverse effect, she explains, is also complicated by the way a few cruise companies operate, by redirecting business away from local businesses towards their partners.

“Cruises have their selected partners on shore, and you often see staff warning passengers of local places that will allegedly rip them off. A disconcerting example is Murano, in Venice, where a few years ago a boom in cruise ship partnerships on shore saw a spike of Murano glass counterfeits. Tourists bought objects from the recommended list of shops, only to later discover they were imported from China.”

Visiting the local area for only a couple of hours and not engaging with its local businesses points to a disconnect between the cruise ship – an endless provider of entertainment – and the destinations where the ship docks, which become an afterthought.

Turning tides

Cruising can set sail towards a sustainable future by shifting gears from what Becker calls a “constant party at sea” to celebrating and respecting destinations.

Small operators – taking a maximum of 500 passengers compared to 8,000 on the biggest ship – make that ethos their unique selling point. That isn’t to say they ditch the extravagant dinners and luxurious suites, they just choose to operate smaller ships where numbers, fuel and waste are better controlled.

Cruise providers like National Geographic-backed Lindblad Expeditions and HX (formerly Hurtigruten Expeditions) are among the smaller operators challenging the status quo. Their solutions include no single-use plastic on board, strict waste disposal protocols and sourcing food from local providers.

“At HX, we choose to offer a more refined dining experience while minimising waste. Even at our buffets, we focus on presenting individual portions,” says Stefan Engl, HX’s vice-president of hotel operation.

“This approach improves the visual appeal of the buffet, but also it helps us control portion sizes and reduce the likelihood of food waste, which is something we monitor daily to keep improving.”

Small operators are not the only ones pledging to be more sustainable. Bigger companies are often involved in charity programmes, from funding local reef restoration initiatives to sponsoring beach clean-ups.

And while supporting eco-conscious activities is a great start, bigger-picture impact can only come with systemic change, and that involves curbing the number of passengers on board instead of continually growing capacity.

Not only do bigger ships gulp up more fuel, the average CO2 emission per passenger increases significantly too.

“There is a scary trend of enormous ships being built, which I really don’t like,” says Becker. “Who enforces what they do? And who checks their environmental claims? Each country has their own rules so it becomes even harder to track their impact.”

Radical measures have been taken. Amsterdam’s mayor closed one of the major cruising harbours because of disruption to local life and in Venice, Unesco curbed cruise numbers to prevent further coastal erosion.

But it doesn’t need to be all or nothing. “Governments will recognise that controlling cruise numbers and sizes is not a cut in their pocket, but a huge investment where everyone benefits – from the local shops to the average citizen,” Becker adds.

If the cruising industry wants to turn the tide in the long run, the focus should shift from making bigger ships to making better ships – reversing the trend of negative impact on destination to become, once again, a beacon of adventure and expedition at sea.

Cruising in stats

31.7 million travelled on a cruise in 2023

That is a 7% rise on the number of passengers in 2019

27% in the last year are cruisers on their maiden voyage

A cruise ship’s carbon footprint can surpass 12,000 cars

The current largest ship is Icon of the Seas: it weights 248,663 gross tonnes and is 365 metres long. Its maximum capacity is 7,600 passengers and 2,350 crew

Cruising generates over £114bn in economic activity annually and supports 1.17 million jobs

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