The cruise industry is largely silent about its plans to comply with upcoming carbon intensity rules, but it has set its sights on improving the efficiency of its existing fleet and eliminating CO2 emissions in the coming decades.

Carnival chief executive Arnold Donald told analysts on a recent conference call of its "leadership" efforts to "accelerate decarbonisation".

Upcoming regulations

Last June, the IMO adopted an Energy Efficiency Existing Ship Index that will require vessels to meet current Energy Efficiency Design Index standards for newbuildings.