This one is highly misleading. They may produce some very specific pollution more than entire Europe together, but pollution overall will be clearly lower.
Emissions of just C02 is about 4000 megatonnes in just EU ( https://en.wikipedia.org/wiki/List_of_countries_by_carbon_di... )
4000 / 10 / 365 = 1.1 megatone per day.
I am not expert on ships, but emitting 1 100 000 000 t of C02 per day seems unlikely.
Most freight ships will burn marine fuels such a 'bunker fuel' when they are offshore not near ports, largely due to the health risk of increased PM in the air near ports.
The issue with fuels as unrefined as 'bunker fuel' (the thing is practically crude) is that they emmit a really high concentration of other gas other than CO2, namely SO2 and NO2.
> "SO2 shipping emissions are projected to increase and by 2020 exceed SO2 emissions from all land-based sources such as power plants in the EU, which over the past several decades have been reduced dramatically at great cost to industry." [0]
CO2 is obviously our major pollutant but Sulphur dioxide (SO2) is a major green-house gas contributor. The frustrating thing about bunker fuel is that it is used offshore purely because it is cheaper and there is no regulation curbing it. As with almost all things environmental related we go back to the hidden long-term costs of having something cheap in the short-term.
[0]https://www.transportenvironment.org/publications/sulphur-ma...
Small molecules like those in propane, naphtha, gasoline for cars, and jet fuel have relatively low boiling points, and they are removed at the start of the fractional distillation process. Heavier petroleum products like diesel fuel and lubricating oil are much less volatile and distill out more slowly, while bunker oil is literally the bottom of the barrel; in oil distilling, the only things denser than bunker fuel are carbon black feedstock and bituminous residue (asphalt), which is used for paving roads and sealing roofs.
SO2 appears to actually have a negative greenhouse gas effect: https://www.carbonbrief.org/sulfur-emissions-may-have-slowed...
You make it sound more factual than it is, it's a computer model projection.
From the same paper you linked:
> "Although the new paper acknowledges the that the slow-down could be a result of natural variability in the climate system"
Which is currently the consensus agreement on this.
And yes, something should be done with pollution generated by shipping industry. Though I wonder what else you can do with bunker fuel. Store it?