Shipowners have less than two years to decide if they want to slow down, invest in technology or scrap their vessels to meet upcoming rules on emissions.

Some ships will be required to comply with the International Maritime Organization’s recently agreed efficiency standards for existing ships, known as EEXI, as early as the third quarter of 2022.

Charles Haskell, manager of the Maritime Decarbonisation Hub at Lloyd’s Register, has already had shipowners asking him when and how to comply with...