The cruise industry causes multiple, diverse and large-scale environmental and social impacts:

• destruction of marine and coastal ecosystems
  
  
• air and water pollution (discharges, spills, toxic paints...)
  
  
• labour precarity, both in the urban fabric and on the ships themselves
  
  
• overtourism in host cities
  
  
• generation of enormous amounts of waste managed locally
  
  
• increased consumption of local resources such as water and energy
  
  

Many of these consequences are deliberately hidden by the industry in its advertising, which often portrays cruises as models of sustainability and environmental care. As with aviation, some of these ads have been reported and withdrawn for spreading false claims.

“Green” fuels

Cruises are among the most polluting forms of transport. Their main fuel is heavy fuel oil (HFO), a dirty petroleum residue. This fuel emits large quantities of sulphur dioxide (SO₂), nitrogen oxides (NOₓ), fine particles and heavy metals, severely degrading air quality in port cities like Barcelona, Palma or Venice, the most affected in Europe by cruise ship pollution.

In Barcelona’s seafront, for example, NO₂ levels reach four times the WHO recommended limit.

To minimise these emissions, cruise companies promote the use of liquefied natural gas (LNG), which can have similar or even worse effects on global warming, and scrubbers, a supposed technological solution that shifts pollution from air to water, threatening marine biodiversity.

Outrageous waste

Cruise ships generate huge amounts of waste, much of which ends up in the sea. It is estimated that each passenger produces 3.5 kg of solid waste and 340 litres of greywater per day —double the amount a person generates at home. While part of this waste is treated, a significant portion is discharged directly into the sea, harming marine ecosystems.

In short, the cruise industry relies on highly polluting fuels and harmful environmental and social practices. Far from being a sustainable or environmentally friendly activity, it stands as one of the clearest symbols of extractive, predatory tourism.