[margalabargala]

There's exactly one scenario that results in the actual technological collapse of our species, which is all out nuclear war between the US and Russia. Which with the current presidential administration, is possibly less likely than it's ever been; why would Russia nuke its newest ally?

The chances of a nuclear weapon being used somewhere right now tactically I think are quite high. Russia in Ukraine, or Israel in Iran (or someday soon Iran in Israel), or between India and Pakistan. But none of those are sufficient to bring us to a point where home manufacturing of solar panels becomes remotely worthwhile.

[adrianN]

I believe it's optimistic to think that that is the only scenario. Consider the problems we had during the pandemic, which was luckily just a minor blip as far as possible global disruptions go.

[lukan]

The problem is, except for the very first ones in Japan, there were never any nuclear weapons being used in a major war exactly for the unknown consequences of the other players.

It is all interconnected. If one nuke is used, then there will be many on the other side applying pressure to also use a nuke. And so on. I assume much more countries secretly have nukes and the frontlines are somewhat blurry. Meaning, at the moment I am also not too worried, but if a nuke is used it will be a very high gamble, that it will be just the only one.

[margalabargala]

Most countries definitely do not have nukes. There are a handful that could have them in secret, or that maintain the materials to make them immediately if needed. But all of those combined would amount to no more than a few dozen, small, nuclear weapons. There are not a thousand Tsar Bomba size nukes secreted away.

If the US and Russia stood down and the rest of the world let loose all of their nukes, it would be insufficient to cause sufficient damage to the technological integrity of our species such that backyard solar manufacture becomes viable.

[lukan]

"Most countries definitely do not have nukes."

I did not claim that.

I claim it will be hard to limit the use of nuclear weapons.

Just like in the weapons itself, one ignition can trigger a chain reaction in the end forcing russia or US to take part in it as well. If all the people involved are level headed and able to think rational - it likely will prevented also in the future. But if the person in charge is already stressed (and old) and gets lots of pressure - this person, might then feel forced to press a button.

[margalabargala]

You said "I assume much more countries secretly have nukes".

I claim that beyond the open secret that is Israel, the number of countries controlling a right-now detonatable nuclear weapon who are not on the Wikipedia list of "countries with nukes" is less than 5.

[lukan]

Claiming much more countries secretly have one, is not at all the same as claiming most countries secretly have them. And I agree that it won't be many many, but in this context one previously unknown bomb already might change lots of geopolitical equations and their outcome.

[margalabargala]

No one ever said most.

You said much more. I think it's fewer than 5.