There have been so many accidents. Does anyone else remember when a satellite launch in the 90's from Scandinavia followed exactly the trajectory of a "blinding" shot to Russian radar and only their willingness to wait and see prevented retaliation?

https://en.wikipedia.org/wiki/Norwegian_rocket_incident

If America was not a military empire, we could try downsizing our nuclear forces to a so called minimal deterrent of a few hundred nukes and then negotiate with other countries to progressively downsize. We won't though because nuclear diplomacy is how we convince other countries to submit. It's not outright threats, but the quiet knowledge that we could incinerate them if we wanted. Plans were laid for doing so during the Vietnam War. To our planners, the non-offensive use of nuclear weapons is not absolute like we would like to imagine it is. America still has a first strike policy.

That was certainly true during the Cold War, with two implacably opposes factions that have no dependencies on each other and no real understanding of each other either. It was terrifying, and mistakes were made that brought us extremely close to catastrophe.

I think that less of an existential threat now. The works us a lot more interconnected and interdependent. What would Russia be without the west to export its oil and gas to? What would China be without foreign markets? We all need each other. Proliferation means the risk of nuclear terrorise or limited conflict us still significant, but not at the globe killing level we had 40 years ago. A limited or regional nuclear exchange would be catastrophic, but not species killing.

>> But in reality, all it takes is a mistake or a madman to set off nuclear armageddon.

> The works us a lot more interconnected and interdependent. What would Russia be without the west to export its oil and gas to? What would China be without foreign markets? We all need each other.

The argument was "all it takes is a mistake or a madman." Neither cares about the fact that "we all need each other."

If you worked anywhere in tech long enough, you should be aware how much unexpected errors are indeed possible even in "old and tested" workflows.

And some madman is always somewhere where "everybody thought he's so nice."

> A limited or regional nuclear exchange would be catastrophic, but not species killing.

Note: "species" and "civilization" aren't the same.

OK, what is the scenario where a single madman causes a complete simultaneous nuclear conflagration by the USA and USSR, the only countries with enough bombs to cause a global nuclear holocaust?

Russia and the USA have no interest in destroying each other. All the other nuclear powers are too small fry to cause more than regional damage.

> what is the scenario where a single madman causes a complete simultaneous nuclear conflagration

An actual nuclear war planner wrote a whole book about that:

"The Doomsday Machine Confessions of a Nuclear War Planner"

https://www.bloomsbury.com/us/the-doomsday-machine-978160819...

P.S. USSR doesn't exist anymore.

There is certainly less of a threat. But imagine what a small fraction, say a few dozen thermonuclear bombs, a couple SLBM's worth, would do to major population centers and the economies they power. That and the after effects would be enough to call the continued viability of modern civilization into question.

Nuclear weapons remain the surest way to end civilization on this planet, and the chances of that happening are far higher than, for example, a meteor strike.