Have a look at a google search on “cargo ship pollution” and draw your own conclusions.
Simply moving cargo, the lifeblood of our economy, across the oceans burns hundreds of tons of fuel oil - releasing more (and more varied) pollutants into the atmosphere and oceans. One ship, by some reports, emits as many emissions as some 50 million (or more) cars. And there are well over 9,000 on the ocean.
And that is why researchers are proposing we bring back Zeppelins! Zeppelins that are 10x as long as the Empire State Tower is tall, to be exact. Way better for the environment, can be operated autonomously, and cheap to produce.
If I take hanniabu's numbers, that ends up with 8000 ft. zeppelins--the length of airport runways. That's probably not going to be operationally viable: going by the space the largest seaports take up today, you have space to berth only a few of them--maybe 5 at best--at the very largest of them. There's therefore going to be very poor operational flexibility for choosing routes, and with the sheer size and capacity, multi-destination itineraries are going to struggle with long dwell times to partially load/unload them.
You figures are incorrect, this is taken directly from the linked article:
> As proposed in a recent scientific paper, the new airships would be 10 times bigger than the 800-foot Hindenburg — more than five times as long as the Empire State Building is tall
Those numbers are for some very specific substances (which are also bad, nobody's contesting that), but not for CO2-equivalent emissions. It's the same kind of dumb number as that cloth bag reuse count vs plastic. Technically true for some aspect, but utterly misleading.
The Wikipedia article does not say this: « It also includes greenhouse gas emissions. The International Maritime Organization (IMO) estimates that carbon dioxide emissions from shipping were equal to 2.2% of the global human-made emissions in 2012 »
