Much has been made of the carbon emissions of commercial airlines. Comparatively little has been said about the pollution coming from cruise ships, though a recent study found that the large boats emit more pollutants per passenger than planes. Of course, there aren't as many ships in Royal Caribbean's fleet as there are planes in American Airlines hangars. It's only natural that airplanes get the majority of the press when it comes to pollution.

But air travel is (quite arguably) a necessity of modern life. It's a practice in logistics: getting from point A to point B. Judging by the usual demeanor of fellow economy class passengers, no one is relaxed or filled with enjoyment when traveling on an airplane. Cruises, on the other hand, have an element of frivolity. No one takes a cruise to get somewhere. People take a cruise to take a cruise. The dirty diesel fumes and sewage dumped into the ocean are unfortunate side effects of that frivolity. Despite the cruising industry doing more than ever to lessen its impact on the environment, some of its critics have arguments that are hard to ignore.

At the same time, it would be difficult to contend that the cruising industry is completely unnecessary. You wouldn't walk around the Cayman Islands telling local hospitality workers and shop owners that cruise ships are evil. Without these floating cities docking regularly, the local economy would slump drastically.

Industry heavyweight Royal Caribbean and other smaller lines have made moves toward greening their ships and procedures. Environmental advocates are skeptical, pointing to practices like the dumping of waste at sea and the continued use of diesel engines, which run on low-grade fuel with high carbon and particle emissions.

But Royal Caribbean and Holland America still contend that they're taking serious steps in a green direction. Is there any truth behind their statements, or are they merely applying cosmetics to the surface of the problem to hide what's going on beneath?


Cruise ship engines are notorious for their emissions. While swapping out old engines for new ones is not possible, there are other alternatives. Cruise line Holland America is at the forefront of the green engine movement. Its newest cruise ship, the Zaandam, has an advanced exhaust "scrubbing system" that uses sea water to reduce the amount of sulfur and particles that leave the smokestack. The sea water is then treated to remove any harmful byproducts. This process, once further developed, can be used on cruise ships as well as other large maritime vessels.

Greening like hotels

Royal Caribbean's fleet has adopted energy-saving practices similar to those used by hotels. It opts for fluorescent lights, high-efficiency appliances and low-flow showers and faucets. As many hotels have discovered, these practices are also money savers. For Royal Caribbean, consuming less electricity means less reliance on its fuel-powered generators.

Other cruise lines are taking small steps as well. Norwegian Cruise lines started a unique recycling program two years ago. Its used cooking oil is unloaded on shore and sent to a refinery where it's used to make biodiesel.


One of the biggest problems is that it's hard to police cruise ships when they're traveling the open seas. Industry behemoth Carnival Cruises watches itself, to a point. An environmental protection officer is on board to ensure the company's green policies are implemented by crew and cruisers. This will become more important as regulations regarding sewage come into effect over the next two years.


One of the loudest criticisms of the industry stems from its sometimes casual treatment of sewage. While it's still legal to dump raw sewage and pulped food waste 12 miles offshore, new measures set for 2010 will make sure all ships have either a sewage holding tank that can be emptied once the ship comes into port or an onboard sewage treatment plant that will purify waste before it's dumped. At least one large company, Royal Caribbean, already boasts state-of-the-art wastewater treatment systems onboard its vessels. Other lines are balking at the new rules. Alaska's government approved five-year waivers for ships that currently don't have proper wastewater treatment facilities.

Less pollution in port

Some lines have begun to plug into shore electricity while in port. This allows them to only run their engines and generators while at sea. The process of shutting off engines and plugging into the port's electrical network is known as "cold ironing."

But there are several problems with this approach. Plugging into land-based power grids is much more costly for cruise companies than continuing to power the boat with generators while in port. In addition, older ships have to be retrofitted with different electrical systems so they can actually plug into land-based sources. Princess Cruises was the first company to rely on cold ironing whenever possible. West Coast ports like Seattle and Los Angeles have facilities for cold ironing, and there's a major movement to mandate the practice on the East Coast, where pollution in some ports is a cause for concern among citizens in nearby neighborhoods.

Smaller is (usually) greener

Smaller cruise lines are generally greener than the big boys. Of course, going completely green is a near impossibility unless you can afford to charter a private, wind-powered yacht and choose to forgo fuel-powered generators. Unfortunately, it's a case of going greener only if you can afford it. Some commercial companies toy with the use of wind power. Luxury cruise company Windstar has a fleet of three vessels powered by an advanced, computer-controlled sailing system. Of course, fuel is still necessary to provide electricity.

Ecoventura, a tiny cruise company that specializes in trips between Ecuador and the Galapagos Islands, recently launched a ship that's powered — partially — by 40 solar panels and two wind turbines. Even with this technology, the ship still relies mainly on gas power to get from point A to point B. In a way, Ecoventura's environmentally friendly developments characterize those of the cruise industry as a whole: definitely welcome, even a bit dramatic, but there's still a long way to go.

Cruise control
Big cruise ship companies like Royal Caribbean are taking steps to clean up their act. But is it enough?