Based on what a reasonable carbon price should be, I don't think you would need to tax them to oblivion. They would just need to pay their fair share.
This website suggests that it is about 0.4 tonne of CO2 per passenger per day. Canada's current carbon tax is $65 per tonne. So a 7 day cruise would be $182 per passenger in carbon pricing. This is just ballpark and yes you can argue that carbon prices should be higher.
Otherwise!