From the fucking article: Fossil fuel cargoes travel long distances in very large flows, so their decline removes more than a proportional share of cargo mass. It removes a larger share of the ocean work and the fuel burned to do that work.

And if I can get on my soapbox. This same problem (carrying fuel to feed the transportation unit) is well studied in medieval England because it was one of the main determinants of where cities and castles were placed (albeit unknowingly at the time). And we see what happened in England when they were able to get out from under feeding oxen.

So 10% is a lot.

It is so weird that it makes 40% sense of 50% its length.

It's saying that 40% of the tons of cargo loaded onto ships is fossil fuels, but this makes up about 50% of ton-miles, because fossil fuels travel further on average than other cargo. Not the easiest headline to correctly parse.

It’s trying to say what if we didn’t have to haul energy around from place to place but generate it closer to consumption - we could move more useful stuff instead.

That is not what I understood from the article. What I understand is:

Fossil fuels are 40% of freight tonnage, but transporting them fuels is responsible for 50% of the total freight fuel consumption.

I assume 99% of freight uses fossil sources as fuel.

The preposition ("butt") is wrong