> Primarily vegetarian diets and less driving would make mountains of difference for the world.
Changing diets yes. Changing driving habits, not really. Personal use of passenger vehicles accounts for a tiny fraction of transportation related CO2 emissions. The overwhelming majority comes from cargo ships and associated logistics.
A typical cargo ship will burn about 30 liters of bunker fuel (far more polluting than diesel) to travel 1 meter. 15 typical cargo ships emit as much CO2 as all cars on the planet combined. There are about 15,000 such ships operating today, with a further 30,000 slightly smaller ones. A single cruise ship company like Carnival Cruise emits more CO2 than all of Europe's car's combined.
Even if the entire world converted to zero-emission EVs overnight, it wouldn't make a meaningful dent in these numbers.
The inconvenient truth is that in order to make a serious dent on transportation related CO2 emissions, the entire developed world would have to give up its lavish lifestyle of internationally shipped products and foods. Sadly a harder sell then 'drive an EV to save the planet lol', so our governments continue to focus on inconsequential but easily attainable measures. And that is nothing to say of the fact that cutting down international shipping is at odds with free market capitalism that's driving our civilisation.
Fun fact: bulk carrier shipping is so cheap that in Australia, locally caught fish are shipped to China for processing and freezing and then shipped back here for retail. The pollution associated with this alone is more than the sum pollution of all Australian cars.
Ships individually use vast amounts of fuel, but are small in overall number (there are about 60-80,000 registered cargo vessels), and achieve efficiencies up up to ton-miles per gallon of fuel, as compared with 500 ton-miles/gallon for rail, 100 for trucks, and less than 10 for cars. Moving cargo by water is the most efficient option that exists by a long shot.
Where cargo ships have bad emissions is in particulates and sulfur, based on what fuels are burnt and how. CO2 emissions, however, are quite low relative to any other transport mode.
For those for whom the suspence has been simply unbearable: Marine cargo shipping achieves cargo fuel efficiency rates of as much as 1,000 ton-miles/gallon.
For passenger cars, the low mileage expressed in ton miles is largely due to the very low cargo utilisation. I'm using a single passenger of 150# here. You can increase net efficiency somewhat, but even, say, four 250# passengers and some luggage makes for only a modest improvement, as the starting point is single-digit tmpg.
>Personal use of passenger vehicles accounts for a tiny fraction of transportation related CO2 emissions. The overwhelming majority comes from cargo ships and associated logistics.
while this might represent a small fraction of the global total emissions, the CO2 (and other harmful particles) produced by cars is much more detrimental to human health since it will be concentrated in the cities and near humans live.
The cargo emissions should be less harmful as there are not many people living in the oceans and algae effect should also be considered as it produces most of the oxygen we breath.
This is correct. If we ignore catastrophic climate change, the next worst thing is being directly exposed to personal transportation pollutants - amongst which CO2 is pretty benign but there is far worse stuff.
Living next to major roads or highways significantly reduces life expectancy.
Particulates and SO4 are short-term acute pollutants. They are problems, but the problem is localised (shipping routes, ports), and settles out fairly quickly.
The scope is significant -- you can see shipping lanes simply by the SOx emissions, as the Nullschool Weather Visualiser shows, here, traffic between Indonesia and the Gulf of Aden is clearly visible:
But: CO2 remains resident in the atmosphere for centuries or millennia, affecting long-term climate. It's a vastly larger problem.
Moreover, particulates and SOx can be mitigated with improved fuel quality and stack scrubbers, at relatively low (though nonzero) costs. CO2 emissions are intrinsic to hydrocarbon combustion. We either have to stop burning anything with carbon in it, or switch to biomass (present-cycle carbon) rather than fossil-fuel based sources. Which is its own problem, though potentially tractable for shipping using various biomass wastestream sources.
But at this point we need to prioritize, and climate change is arguably becoming more important than direct exposure to personal transportation pollutants.
Do you have a source for your claim? Here[1] is a link I found breaking down the fuel consumption by sector. Seems Motor Oil vastly outscores Residue Fuel Oil, which I believe is what tankers use. I may be wrong, though, and would be interested in being corrected.
My actual job is in the shipping route optimisation space. Sub-percentile improvements in fuel consumption for a single route result in hundreds of millions of dollars of fuel savings. Of a fuel that's both cheaper and far more polluting than diesel. It's pretty obvious that shipping fuel consumption and associated emissions eclipse personal transportation.
Your sources are in error. Particularly the first, which I believe is confusing particulate and/or sulfer emissions with CO2 emissions. It cites several further news articles, not a primary source.
The inews source compounds this error, and is cited by the Medium blog.
The newatlas source confirms this: "The low grade bunker fuel used by the worlds 90,000 cargo ships contains up to 2,000 times the amount of sulfur compared to diesel fuel used in automobiles." The measurement is sulfur emissions and NOT CO2.
FT likewise discusses sulfur and not CO2: "Sulphur dioxide emissions from cars was 3.2m kt versus 62m kt from cruise ships, with Carnival accounting for half that, the study found."
The AFR link discusses seafood and not shipping emissions.
True, shipping is absolutely filthy. This was a big part of why I mentioned "less disposable crap".
Though how much is ghg and how much a matter of particulates? Seems most analysis shows the drive to the grocery store emits more carbon than shipping the fish.
Also fish is generally a disaster, but that's a separate topic. (Eating carnivores full of plastic dumping concentrated waste and disease in to the ocean is suboptimal)
Changing diets yes. Changing driving habits, not really. Personal use of passenger vehicles accounts for a tiny fraction of transportation related CO2 emissions. The overwhelming majority comes from cargo ships and associated logistics.
A typical cargo ship will burn about 30 liters of bunker fuel (far more polluting than diesel) to travel 1 meter. 15 typical cargo ships emit as much CO2 as all cars on the planet combined. There are about 15,000 such ships operating today, with a further 30,000 slightly smaller ones. A single cruise ship company like Carnival Cruise emits more CO2 than all of Europe's car's combined.
Even if the entire world converted to zero-emission EVs overnight, it wouldn't make a meaningful dent in these numbers.
The inconvenient truth is that in order to make a serious dent on transportation related CO2 emissions, the entire developed world would have to give up its lavish lifestyle of internationally shipped products and foods. Sadly a harder sell then 'drive an EV to save the planet lol', so our governments continue to focus on inconsequential but easily attainable measures. And that is nothing to say of the fact that cutting down international shipping is at odds with free market capitalism that's driving our civilisation.
Fun fact: bulk carrier shipping is so cheap that in Australia, locally caught fish are shipped to China for processing and freezing and then shipped back here for retail. The pollution associated with this alone is more than the sum pollution of all Australian cars.