Icon of the Seas: The world's largest cruise ship sails from Miami

The world's largest cruise ship is set to sail from Miami, Florida, on its maiden voyage, amid concerns about the ship's methane emissions.

The 365-metre (1,197 ft) Icon of the Seas has 20 decks and can accommodate a maximum of 7,600 passengers on board. It is owned by the Royal Caribbean Group.

The ship embarks on a seven-day island hopping cruise in the tropics.

But environmental experts warn that the LNG-powered ship will leak harmful methane into the air.

Reuters quoted Brian Comer, director of the marine program at the International Council on Clean Transportation, as saying, “It is a step in the wrong direction.”

“We estimate that the use of LNG as a marine fuel results in life cycle greenhouse gas emissions of more than 120% greater than marine gas oil,” he said.

LNG burns cleaner than traditional marine fuels such as fuel oil, but there is a risk of leakage.

Methane, a powerful greenhouse gas, traps 80 times more heat in the atmosphere than carbon dioxide over a 20-year period. Reducing these emissions is seen as crucial to slowing global warming.

A Royal Caribbean spokesperson was quoted in the media as saying that Icon of the Seas is 24% more energy efficient than what the International Maritime Organization requires for modern ships. The company plans to introduce a net-zero ship by 2035.

On Thursday, Lionel Messi, captain of Argentina's World Cup-winning national team, who currently plays for Inter Miami, participated in the ship's naming ceremony. He was seen placing a football on a specially built platform to encourage breaking a traditional “good luck” champagne bottle on the ship's bow.

The cost of building the Icon of the Seas was $2 billion (£1.6 billion). It now features seven pools, six water slides and more than 40 restaurants, bars and lounges.