The carbon calculations seems questionable. The author should include all energy used on board the ship, which is entirely from fossil fuels. The energy require

The carbon calculations seems questionable. The author should include all energy used on board the ship, which is entirely from fossil fuels. The energy required to desalinate seawater for drinking/washing was probably greater than a flight. Also, an additional, unnecessary person on the ship is slightly increasing the risk of diverting the ship because of a medical emergency. Imagine how much carbon would be burned if this massive ship had to turn around to drop off a sick passenger.