I took part in the Perl Whirl last year, which was my first time aboard a cruise liner. I wasn't convinced that it felt entirely ethical - it was like the ship was this pustule of decadence floating in the innocent blue sea, and the ports that grew up to serve it looked like cancerous growths on the virgin green forest behind. [Although I'm not sure what's left of those ports, given that Wilma visited two weeks to the day after us.]
So it's scary to learn that cruise ships just keep getting bigger. It's somewhat reassuring to learn that my concerns about the environmental impact of liners aren't unfounded (3rd and 4th paragraphs from the end), but in turn that doesn't seem to stop the liners themselves just getting bigger again, with plans for a new liners of 220,000 tons with capacity for up to 5,400 passengers by 2009.