The Environmental Impact of Cruise Ships

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By P. Sullivan

In 2017, the cruise industry recorded 25.8 million global ocean cruise passengers. Cruise lines have had to keep up with the ever-increasing demand for cruises by purchasing new vessels and developing cruise ships with more features that would entice passengers. In fact, estimates showed that the cruise industry was worth over $117 billion in 2017.

Each year, the cruise industry visits new destinations across the globe, with the Caribbean as the most sought after destination. The more cruise ships there are, the more the world feels the environmental impact of their presence, particularly in the most popular cruise ports.

Effects of cruise ships on the environment

A coalition of 53 environmental advocacy groups signed a petition in 2000 for the Environmental Protection Agency to investigate cruise ship pollution. Cruise ship pollution includes the wastewater, solid waste, and oil that cruise ships discharge into the ocean. Two decades since that petition was submitted, the problem of cruise ship pollution persists.

The pollution from these ‘floating cities’ comes in several forms:

Blackwater, the wastewater from toilets, can contaminate the ocean if not correctly treated. The sewage can contain viruses, bacteria, parasites, and other pathogens that harm shellfish beds and fisheries and contribute to the growth of algae. Excessive algal growth can result in the death of fish by reducing the amount of oxygen available for the fish to survive. To put it into perspective, one large cruise ship can produce up to 30,000 gallons of blackwater in just one day.

Life and Wellness –

Gray water, the wastewater from cleaning activities, can contain medical waste, dental waste, fecal coliform bacteria, detergents, and metals. Cruise ships often release untreated gray water into the ocean, likely harming the environment due to the high levels of foreign substances like nutrients. One large cruise ship produces around 200,000 gallons of gray water a day.

Air pollution, created by cruise ships’ diesel engines, takes a toll on the ports in which the vessels dock. The fuel that the engines burn releases chemicals such as nitrogen oxide, sulfur dioxide, carbon monoxide, and carbon dioxide into the air. It does not only act as a carcinogen among humans but adds to the visible degradation of water. Cruise ships produce greenhouse gas pollutants, black carbon, and nitrogen oxide, undoubtedly making them a significant factor in climate change. According to Forbes Magazine, a cruise ship passenger’s carbon footprint is triple the size of their carbon footprint when on land.

Solid waste, composed of either non-hazardous or hazardous trash, can end up as marine debris and harm non-human animals and humans. Cruise ships usually try to minimize waste production and maximum recycling, but there is still a substantial amount of trash generated. Then, to limit the amount of solid waste stored, the cruise ships incinerate the remaining waste. The incineration process creates ash, which they may release into the ocean, while the rest is brought to land to recycle. Any solid waste in the water can get in the way of marine animals and result in their deaths if they become entangled in the trash. One large cruise ship produces eight tons of solid waste in one week.