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Are cruise ships climate killers?

Felix Schlagwein
June 21, 2019

The sea cruise industry is booming, and yet protests are growing: Critics claim these floating hotel complexes not only pollute the environment, but also bring cities to the brink of collapse. Here's a fact check.

Large cruise ship sailing across the lagoon in Venice, Italy
Image: AFP/M. Medina

It took a whole six hours until the 70,000-horsepower Zuiderdam was able to leave the port of Kiel at the beginning of June. Fifty activists from the group Smash Cruiseshit blocked the ship's progress with canoes and rubber dinghies at the port exit — until the protest was disbanded by a special task force of the police. Though criticism of cruise tourism is growing, the industry is booming at an unprecedented rate. In 2018, 28.5 million tourists booked a cruise on a floating hotel worldwide, more than 2 million of them from Germany, and the trend is rising.

What used to be a fantasy for many is now affordable for the masses thanks to lower prices.
Environmentalists point out the unsustainable nature of the cheap dream voyages. The world's 300 cruise ships consume a heavy amount of petroleum, running on a byproduct of oil processing. Companies gratefully take hazardous waste from the refineries and use it as cheap fuel for their ocean liners in a classic win-win situation for the operators — but not for the environment.

Environment activists block a cruise ship in Kiel harbor
The activist group Smash Cruiseshit blockade the Zuiderdam in Kiel harborImage: picture-alliance/dpa/T. Eisenkrätzer

The combustion of heavy oil not only releases large quantities of CO2 (carbon dioxide), but also toxic substances such as sulfur, fine dust and heavy metals. It is not only the environment that suffers as a result. The inhabitants of coastal cities are also increasingly complaining about polluted air. After all, the air conditioning, lighting and heating systems on ships must continue to operate even in ports. At least the ships in the ports switch to the more expensive marine diesel. It is a little cleaner than heavy oil, but still contains plenty of pollutants.

In theory, these white sea giants could also draw electricity from land while they are moored, which on most cruises accounts for around 40% of the total time. So far, however, only two ports in Europe — Hamburg (Germany) and Kristiansand (Norway) — offer shore power. In order to purchase this electricity, the companies would have to retrofit their ships at great expense. But financial incentives and political pressure to do so have been lacking. Even ships with shore power connections usually do not use them.

Pool on a deck of a cruise ship in Montenegro Bay
Fun and games on a floating hotel: Cruises are no longer just a privilege of the wealthyImage: picture-alliance/Bildagentur-online/Mahaux - AGF

Land power is a good option, Helge Grammerstorf, head of the German branch of the Cruise Lines International Association (CLIA), told DW. "But we have to get green electricity from land," he said. "Otherwise, it doesn't make sense from an ecological point of view." The pollution levels in the port cities would fall, but not in the vicinity of the coal-fired power plants. In addition, green electricity must be available at good economic conditions. "This is what we are working on — and the prospects for success are quite good." But one thing is certain: As long as there is no nationwide network and the electricity is too expensive, the diesel engines will continue to run and thus pollute the air of the port cities."

'Extremely controversial'

Industry representatives say billions are being invested to make ships more environmentally friendly. Grammerstorf said the main focus was on liquefied natural gas (LNG) and exhaust emission control systems.

Last year, the AIDAnova was the first ship in the world to be launched with LNG propulsion. LNG is much more environmentally friendly than heavy oil: no soot particles, almost no nitrogen and sulfur emissions and 20% fewer CO2 emissions. However, LNG is mainly obtained by fracking, a process that involves such high environmental risks that it is largely banned in Germany.

People watching the  AIDAnova cruise ship sail
The AIDAnova takes to the seas in autumn 2018Image: pictrue-alliance/dpa/M. Assanimoghaddam

And LNG is expensive. In the foreseeable future, the industry will continue to rely on heavy fuel oil — despite the fact that the UN's International Maritime Organization has already adopted stricter limits for sulfur and nitrogen content in fuel. "The hope that the sulfur limits will automatically get rid of the heavy fuel oil will unfortunately not be fulfilled," Katharina Koppe, from the Federal Environment Agency, told DW. Koppe said the exhaust emission control systems, the so-called scrubbers, were "extremely controversial." They reduce the emissions of cruise ships, but, at the same time, they pollute the oceans with their wastewater.

Are cruises unsustainable?

Cruises account for only 2% of global tourism. By comparison, almost 60% of travelers flew to their holiday destinations in 2018 — and the climate damage from commercial flights is much more devastating. It is also worth taking a look at maritime shipping as a whole. In comparison to the 40,000 merchant ships, which handle 90% of global shipping and use the same fuel as tourism vessels, the 300 cruise ships appear to be an almost insignificant number.

It is not only the environmental impact of cruise ships that is problematic, however. The cruise boom, like low-cost airlines, has changed tourism considerably. The floating hotel complexes spew thousands of visitors every day into cities such as Amsterdam, Venice and Dubrovnik. The tourists stay only a few hours. They eat and sleep aboard their floating hotels; city tours and museum visits are usually organized by the cruise operators. The local tourism industries tend to lose out. What remains are annoyed residents and a lot of garbage.

Protest against tourist hubs in Venice
Demonstrators protest cruises in Venice after the MSC Opera rammed a tourist boatImage: Getty Images/AFP/M. Medina

Cities like Dubrovnik in Croatia and Bergen in Norway have even reduced the number of cruise ships permitted to moor in their ports to slow the growing rush of people. Palma de Mallorca wants to follow suit. Other cities, such as Venice and Amsterdam, have announced that they will ban cruise ship from city center docks.

The CLIA's Grammerstorf said such measures were unnecessary, as so few tourists arrive on ships. "In Barcelona the figure is just 8%, in Venice only 5%," he said. "In other words, even if there were no cruises at all, more than 90% of the visitors would still be in the city." He added: "Of course we have an interest in sustainable tourism, because we don't want the destinations on our trips to become less attractive." In addition, the cruise industry is still a very good business for port cities.
Even if cruises only account for a small proportion of mass tourism and its environmental impact, there is another factor to consider: Compared to the global travel market, the industry is growing disproportionately fast. In the coming years, more and more ships will cross the oceans and with them more and more tourists.

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