Hacker News Reader

Comment by tensor | Hacker News Reader

No, excessive fossil fuel use is the cause by an immense margin. It's completely dominated by commercial shipping (boats), followed by planes. Then I think it may actually be gas from cattle before cars. Bitcoin and AI are so recent and still relative to everything else small.

View on HN

This is completely incorrect. Aviation contributes 2.5% of global emissions (but is terrible on a per capita basis, as only around 10% of the world's population travels on any given year). Global shipping accounts for 2.3% of global human-made emissions [1].

In transport emissions, passenger vehicles dominate by far (with around 12% of global GHG emissions), even more so in developed countries. Then freight by road with 7.5% of total emissions.

Maritime shipping is actually the least carbon intensive way to transport goods over long distances by at least two orders of magnitude [2].

[1] https://ourworldindata.org/co2-emissions-from-transport

[2] https://www.ipcc.ch/report/ar5/wg3/transport/06_figure_8-6/

Electricity (including heating) is actually the single biggest source of greenhouse gas emissions, but transport is indeed number 2: https://ourworldindata.org/emissions-by-sector

Followed by agriculture & manufacturing.

Is that so? Too bad nuclear civilian ships are not common. https://en.wikipedia.org/wiki/Nuclear_marine_propulsion

I really feel like if the US really wanted to support US shipbuilding (like what the Jones act was supposed to do) it would subsidize building a fleet of nuclear shipping boats.

Lots of manufacturing projects, lots of related industries boosted, a renewed investment in nuclear engineering bringing a lot of nuclear job experience, and a way to potentially dig deeper into the backbone of global trade again.

I love the theory, but the security concerns around nuclear anything are a big deal when we're talking ships that sail around the world.

Imagine if even one of the tankers hit in the strait of Hormuz was nuclear.

It would have sunk to the bottom and been of no immediate concern. The benefit of nuclear reactors on boats is that you can drown it out at anytime. The only real concern is a nuclear ship getting beached and not having the passive failsafe of sinking underwater.

Would Iran be as likely to have hit one of these ships if the result was potentially a nuclear meltdown close to their shoreline? It would pretty radically change the costs to them for such an attack, wouldn't it?

If you sink nuclear ship you won't get nuclear meltdown. You have enough thermal mass to cool down anything if you are underwater. Some level of loss of nuclear material would happen. But meltdown is not something that would happen.

Its not like all the ships hit by attacks in the Straight of Hormuz sank. A ship could potentially become critically damaged and become unable to operate the reactor and still be floating.

Either way, "loss of nuclear material" is the real concern isn't it, instead of just the nature of how that loss happened?

The question still stands. If a country knows they're potentially going to cause a nuclear disaster by hitting one of these ships on their shoreline, are they as likely to shoot at them?

The hardliners might want to cause a nuclear incident to keep the strait closed longer.

And even among the non-hardliners mistakes are rampant in war. It's not about what they're likely to rationally do, it's about what some local, demoralized missile officer who graduated in the bottom 20% of his class does when he's cut off from command and drinking too much.

Not every culture encourages the same principles or values as yours. I'd say they possibly would.

Are there cultures out there which wish for important parts of their own country get turned into nuclear wastelands?

If Iran wants to make their country a nuclear wasteland, they don't need to blow up ships to do it. I'd imagine they probably don't want that outcome, but hey I'm not an Iranian so I can't speak for them.

I kind of figured that'd just be a "logical" thing and not necessarily a "cultural" thing, but I agree I don't know all cultures.

Widespread use of nuclear power for civilian merchant shipping is a non-starter. It's simply too expensive to train and pay enough qualified nuclear engineers. The US Navy barely manages this for a few dozen nuclear powered vessels with a huge budget and limited concern for cost effectiveness.

Plus there are the security concerns. Every civilian nuclear power plant has armed guards on duty around the clock. Those guards have to also be trained and paid. Many foreign countries have laws against bringing weapons into their ports.

If we want to reduce CO2 emissions from merchant ships then use nuclear or renewable power on shore to manufacture carbon neutral synthetic liquid fuel. Use that to run the ship engines.

Reply on news.ycombinator.com