Instead, it is the job of the International Maritime Organisation (IMO) to negotiate a reduction in emissions from the industry.

I was going to say, possibly an international organisation to regulate the commons of the climate would be good, but that there would be too many pitfalls for it to be viable without the option for people who don't like potential corruption of it to go to other planets, which we don't have nearly enough infrastructure for. Sadly, governments made this anyway :/ . Hello, world government!

<edit>Perhaps it would almost work if it only had authority of the environment and even then, only when net global emissions were over 0, but there has already been a potentially worse and more authoritarian organisation created anyway, so I guess this speculation doesn't matter too much. </edit>

I wish clean energy cargo ships were available; I have looked on sites where one can buy a cargo ship, and none were :/