Check cruiseline policies on emissions
Pick a cruise line with advanced wastewater treatment (AWT) technology, which entails treating water so it’s safe to discharge at sea. Royal Caribbean is spending close to $100 million to retrofit all its ships with AWT (20 are complete now). Norwegian and Celebrity have already installed it on all their vessels. Holland America is testing a new system that uses seawater to scrub smokestack emissions, which decreases air pollution; its Vista-class fleets are powered by either diesel-electric or gas-turbine engines. RCL and Celebrity have added gas turbines to their newest ships, reducing emissions of nitrous oxide by 80 percent and sulfur oxide by 98 percent. Princess is doing its part by turning off engines on several ships while they’re docked and plugging them into hydroelectric-power transformers onshore.