The huge passenger vessels sometimes known as “cruisezillas” are getting bigger than ever, according to new research which has found that the world’s biggest cruise ships have doubled in size since 2000. If the industry’s growth does not slow, the biggest ships in 2050 will be eight times larger, in terms of tonnage, than the Titanic – the largest ship on the seas before it sank a century ago, according to the campaign group Transport & Environment (T&E). The group also found that the number of cruise ships has risen 20-fold since 1970.

“Today’s cruisezillas make the Titanic look like a small fishing boat,” said Inesa Ulichina, a sustainable shipping analyst at T&E. Industry projections suggest about 35 million passengers will travel the seas on cruise ships this year – a 6% increase from pre-pandemic levels which analysts attribute to rising wealth. Research published by JP Morgan in June found that demand for cruises “remains robust” and noted that the cruise industry had moved beyond its core market of baby boomers to increasingly attract millennials.

But the sector has a large carbon footprint, and experts struggling to clean up the industry reacted with alarm to the T&E report. Cruise ships pumped out 17% more carbon dioxide in 2022 than they did in 2019, the report found, and methane emissions rose 500% over the same time period. Stefan Gössling, a professor at Linnaeus University in Sweden who studies tourism and the climate crisis, said cruise .