The shipping numbers are correct. Shipping is incredibly carbon-efficient at moving large amounts of freight.
The pollution problem from shipping is not in the form of carbon emissions. It's in the form of oil spills, NO2, SO2, etc pollution, and it is difficult to accurately estimate. [1]
On the other hand, estimating ship carbon emissions is easy - count how much bunker oil gets produced, world-wide, and assume all of it gets burnt in the engines of cargo ships.
[1] This is why occasionally, you see anti-environment publications push nonesense like 'Gas taxes are stupid, because one cruise ship produces more pollution then every single car in this city combined.'
Yes, in NO2 and SO2. [2] No, not even remotely in terms of CO2. And carbon taxes are intended to... Reduce emissions of CO2, not NO2 or SO2.
[2] Those gases are pollutants, they cause health and environmental problems, but they aren't very important in the context of climate change... Which is what carbon taxes try to address.
Bunker fuel is also heavy in contaminants, including heavy metals, which can also affect local regions (ports, shipping lanes). Most (though not all) are fairly short-lived in the biosophere, at least compared to CO2.
Otherwise largely agreed. I'd commented similarly about 10 days ago:
Not always waste. There are some important collections of atoms that you would prefer to move whole from one place to another, rather than creating new ones on site. Especially since it takes 18 years or more to do!
Other than that, I agree. Home nanotech for everyone!
What are the alternatives of transport mode A to transport mode B?
What are the alternatives to transporting inputs, outputs, and/or wastes?
Per ton-mile (or tonne-km) nothing matches marine shipping. The alternatives to shipping entirely might merit consideration though.
And induced consumption (shipping of X is now so inexpensive that consumption of X increases manyfold), a/k/a the Jevons Paradox, is another major factor.
The pollution problem from shipping is not in the form of carbon emissions. It's in the form of oil spills, NO2, SO2, etc pollution, and it is difficult to accurately estimate. [1]
On the other hand, estimating ship carbon emissions is easy - count how much bunker oil gets produced, world-wide, and assume all of it gets burnt in the engines of cargo ships.
[1] This is why occasionally, you see anti-environment publications push nonesense like 'Gas taxes are stupid, because one cruise ship produces more pollution then every single car in this city combined.'
Yes, in NO2 and SO2. [2] No, not even remotely in terms of CO2. And carbon taxes are intended to... Reduce emissions of CO2, not NO2 or SO2.
[2] Those gases are pollutants, they cause health and environmental problems, but they aren't very important in the context of climate change... Which is what carbon taxes try to address.