cruise ship pollution

Cruise Ship Pollution and Environmental Impact

The popularity of Cruise ship holidays is on the rise, with cruise passenger figures increasing year-on-year. However, cruise ships have long been associated with a bleak environmental impact due to waste generation and carbon emissions. It is estimated that an average cruise ship generates 21,000 gallons of sewage, and emits the equivalent of 13 million cars worth of sulphur oxide per day. With passenger numbers increasing, we take a look at the problem of cruise ship pollution and ask what the industry is doing to tackle the issue.

Ocean Cruise Passenger Numbers

According to the Cruise Lines International Association (CLIA) there were an estimated 25.8 million global ocean cruise passengers in 2017. This is an increase of 1.1 million passengers from 2016, and the CLIA project a further increase of 1.4 million in 2018 up to 27.2 million passengers. This is a booming turnaround for an industry which had numbers of 15 million passengers ten years ago. However, this added growth also brings with it increased environmental pressures which need to be addressed.

Cruise Ship Pollution

Waste Water

It is estimated that the average cruise ship passenger creates 40-50 gallons of wastewater per day. On an average cruise ship of 3,000 passengers, that’s around 150,000 gallons of sewage created per week. It should be noted that larger cruise ships have capacities of up to 8,000 passengers. How this sewage is handled by cruise operators, is a major cause for concern when dealing with cruise ship environmental impact.

Sewage Discharge to Sea

Friends of the Earth in their study on cruise line practices estimated that operators discharged more than one billion gallons of sewage into the ocean in 2017. Much of this waste was raw or poorly treated. Some older ships still use outdated sewage handling systems which have minimal treatment capabilities. Older marine sanitation Devices (MSDs) such as the Type II systems macerate the sewage and add chemical or biological agents before discharging to the ocean. The sewage still contains dangerous levels of contaminants, from fecal matter, bacteria and heavy metals.

The only obligation for a cruise ship operator is to be three nautical miles from the shore before dumping the sewage. Even this stipulation has not always been obeyed, as was experienced at the coastal resort of Armação dos Búzios, Brazil in 2014 when a cruise ship dumped sewage near the coast. Swimmers who came into contact with the contaminated water fell ill, and authorities closed the beaches due to the extent of the pollution.

Cruise Ship Sewage
Cruise ship the Splendour of the Seas discharging sewage near the Brazilian coast. (Image: Indio da Costa, Environment Secretary for the State of Rio de Janeiro, Brazil)

There are obvious risks to swimmers and beachgoers from contaminated water. There is also a risk that seafood can become contaminated and cause illness when eaten. Ocean pollution from sewage contamination also has a detrimental impact on marine life. Fish, shellfish, and corals are vulnerable to suffocation from the excessive phosphorous and nitrogen in sewage-contaminated waters.

Other Sea Pollution Risks

Another wastewater issue is oil contaminated bilge waste from the engine and fuel systems. In 2013, the Caribbean Princess operated by Princess Cruises discharged 4,227 gallons of contaminated water into the sea off the English coast. Evidence supplied by an onboard engineer revealed a secret outlet pipe was used to disguise the discharge, and the ship had been using this method since 2005. Four other ships in the Princess fleet were found to be using similar deception devices. After pleading guilty during an investigation the company was fined £32 million ($40 million).

Air Pollution

Shipping has a significant environmental impact on air quality, with cruise ships adding a significant contribution. The two major air pollutants from shipping activity are SOx (Sulphur oxides) and NOx (Nitrogen oxides) both of which have an impact on greenhouse gas levels and influence climate change. Ships mostly burn low-grade fuel oil with high Sulphur contents which compound the problem. In international waters the regulations on fuel quality are relaxed and ships can use fuel with an even higher Sulphur content. The US Environment Protection Agency (EPA) estimates that an average cruise ship while on the open sea emits the same sulphur oxide contaminants into the air in a single day, as 13 million cars.

Cruise Ship Air Pollution
Air Pollution from the Sun Princess in Hong Kong harbour
(Image: Jason Thien – 2.0 Generic (CC BY 2.0))

What is the industry doing to combat cruise ship pollution?

The latest onboard sewage treatment systems are much improved to the older MSDS. Instead of chemical treatments, the solid matter is filtered and stored for offloading at the port. The water is then disinfected with UV radiation and tested for bacterial levels before discharge. This is a great improvement for marine sewage treatment, but still not perfect as heavy metals can be harder to remove from the wastewater. Sixty percent of cruise ships now run this modern system around the world. This means 40% are still discharging poorly treated sewage to the ocean. The ideal method would be for cruise ships to store all wastewater for offloading while in port. Some shipping operators also operate a policy of discharging water further from the coast than the required 3 nautical miles.

The industry has discussed the use of higher grade fuel oil with less sulphur. The UN International Maritime Organisation has, in fact, placed a sulphur cap on shipping oil which comes into effect in 2020. Technologies such as sulphur scrubbers in the smokestacks can also reduce sulphur emissions. When ships are in port they can use electricity from the dockside power supply if they have the appropriate connections. This prevents dockside sulphur emissions, as power is still required onboard when docked.

Several cruise operators have orders in place for LNG (liquid natural gas) powered cruise ships.  LNG power would be a great step forward to reduce cruise ship sulphur emissions. Carnival Cruise Line is one of the operators to have LNG ships ordered, after signing an agreement with Shell North America LNG to supply LNG for its 7 new cruise vessels. In Germany and Finland, 2 LNG vessels are already under construction for AIDA and Costa respectively, which should be operational in 2020.

Choosing a Cruise Operator to Reduce Environmental Impact

We do not encourage cruise ship tourism due to the overall environmental impact of the industry. But we do welcome the strides the industry is taking to minimise its footprint.
If you decide to take an ocean cruise holiday against our advice try, to find a cruise operator with a good environmental record. It is important to understand the operator’s environmental policies and capabilities before booking.

For example, let us take the case of Carnival Cruise Line mentioned above for their LNG ship orders. When the LNG ships are online they will have a much cleaner emissions profile. However, their current fleet uses outdated sewage treatment technology causing sea pollution.

Friends of the Earth release an annual cruise ship report card which evaluates 17 cruise operators on environmental factors. Cruise Lines are evaluated (A to F) on sewage treatment, air pollution reduction, water quality, transparency, and an overall grade. The only cruise line that received an overall A rating was Disney Cruise Lines. All Disney ships were equipped with advanced sewage treatment and fuel emission systems. Other operators to score highly were Norwegian, Cunard, Princess and Holland America. It also interesting to note that Disney was the only operator to openly cooperate with Friends of the Earth in the evaluation. Transparency from stakeholders is important to fully understand the problem.

Responsible tourism is all about taking ownership and taking action. In the case of ocean cruise holidays, most of this responsibility is absolved from the tourist and placed in the hands of the cruise operator. Only can the operators themselves make the changes necessary to reduce their environmental impact. However, a responsible traveller still has one important responsibility. That is to decide if a cruise holiday is a responsible option in the first place.

We would like to hear from regular cruise tourists about their experiences on cruise holidays. Have you seen any disturbing environmental practices?. Or maybe you have been impressed by cruise operators environmental initiatives. Please let us know in the comments section below.

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One Comment on “Cruise Ship Pollution and Environmental Impact

  1. I’m sure all this does depend on the cruise line and how modern they are and how much they care about the environment. Not all cruise ships are as bad as some!

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