There is an ongoing discussion/debate associated with the international requirements for reduced emissions from ships having an impact on warming.
I work for the shipping industry on the training side, and we constantly adapt our course offerings to any (new) international requirements. Currently many ships powered by 2 stroke diesels are switching over to burning LNG as a fuel because its 'cleaner'. These engines are considered dual fuel- burning diesel as a back up to the boil off gas from the LNG. Pretty complex process from storage of the fuel as a cryogenic liquid to getting it to an acceptable pressure and temperature where it can be injected into the engine.
The article linked below references a UMBC study on warming effects related to reduced SO2 emissions.
https://www.newscientist.com/article/2433564-cleaner-ship-emissions-may-warm-the-planet-far-faster-than-expected/#:~:text=This effect was more acute,average%2C according to the study.