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I remember seeing many news articles and posts on social media saying that a single container ship pollutes as much as 50 million cars. Is this true? How could that be possible?

A container ship on the high seas. The ship is named "EVER GIVEN".

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    As one answer says, one needs to know how pollution is being measured, but such a statement still remains meaningless until one is also told what the reference value is, i.e. per what unit the pollution is being compared. The most helpful would probably be (weight transported × distance), where for a fair comparison the distance should be as the crow flies from start to destination. The extreme ratio suggests that something else is being used, perhaps only distance or even one trip. We should also bear in mind that cars cannot transport across oceans!
    – PJTraill
    Commented Aug 18, 2021 at 10:04
  • Comments are not for extended discussion; this conversation has been moved to chat.
    – Nic
    Commented Aug 30, 2021 at 15:52
  • Please do not write answers in the comments.
    – Nic
    Commented Aug 30, 2021 at 15:58
  • Here is another link. The shipping company is buying eight ships that can run on carbon-neutral methanol. The astounding thing is that the shipping companies might be the only industry that has a clear path to the future: cnbc.com/2021/08/24/… .
    – S Spring
    Commented Aug 30, 2021 at 19:51

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It depends on how you define "pollution".

Cargo ships use some of the dirtiest fuels available: bunker fuel is basically what's left over after you refine all the good stuff out of crude oil. It's got all sorts of contaminants that something like gasoline or jet fuel doesn't have. On top of that, there are basically no regulations on emissions by cargo ships. This results in very high emissions of nitrogen and sulfur oxides, while cars emit almost none -- a ratio of 50 million to 1 is not unreasonable.

Carbon dioxide emissions are a different story. Cargo ships are the most fuel-efficient way of moving things from one place to another, while passenger cars are the least. Per ton of cargo moved, cargo ships are between a hundred and a thousand times more efficient than cars, depending on how heavily-loaded the car is.

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  • I believe the world has changed; most ships now use diesel engines. If it were making steam with bunker C , there would be some level of visible smoke. Because of various restrictions ,bunker c is mostly refined in hydrotreaters, etc. and made into diesel and other oil and gas products.
    – blacksmith37
    Commented Aug 27, 2021 at 14:28
  • @blacksmith37, diesel engines can burn a very wide range of fuels: basically anything that can be aerosolized and undergoes compression ignition can be used in a diesel engine after appropriate modification to the fuel system. Bunker fuel works just fine, as long as you've got a heated fuel system to keep it from solidifying in the lines.
    – Mark
    Commented Aug 27, 2021 at 20:13
  • No, not really, for one ,sulfur is limited to 0.5 % ( No way is that bunker C) . Also there is a viscosity listed ; I an not familiar with viscosity but i would bet a dollar that bunker will not meet it. Also , Sulzer note the fuel is mostly distillate .
    – blacksmith37
    Commented Aug 28, 2021 at 20:17
  • Do you have a source for any of these statements?
    – pak
    Commented Sep 20, 2021 at 13:21

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