Ocean shipping causes a good deal of emissions, about the same amount as all of Germany put together, so lowering this will be good! Some scientists are looking to ammonia as a green fuel alternative but others caution that this solution leaves much to be desired.
Ammonia is a sort of wonder chemical that has many uses, one of which is fertilizer. This means that the process for mass producing ammonia is already set up making it simple to procure. The process of making it isn’t green however and causes emissions. The scientists who performed the study say they have a alternative, green plan for producing it.
The second issue is that it is not as efficient as standard fuel meaning that more cargo space must be given up to cart extra fuel on the freighters. Still, with amble fuel, the chemical is powerful enough to get the ships across the seas, with no CO2 emissions.