We already live in a world where if e.g. North Korea wanted to destroy the huge swaths of our entire species, they probably could. See things such as salted nukes, like a cobalt bomb. [1]. I think there's an even more general lesson there as well. We first utilized nuclear weapons in 1942. Up until that time major developed powers going to war with each other was a relatively normal part of existence. And given that reality, it would not have been unreasonable to predict nuclear weapons resulting in the end of the world. As Einstein witted, "I don't know what world war 3 will be fought with, but world war 4 will be fought with sticks and stones."
But after the realization of nuclear weapons, unrestrained war between developed nations simply ended. And we've entered in what is likely the safest and most peaceful 80 years of human existence ever. I realize how absurd that sounds, but statistically it is almost certainly true. It's hard to even imagine the death toll of previous wars. In World War 2, some 3% of the world's population was killed. Today that would be 231 million people. For some scale imagine a 9/11 type event happening, every single day, for 211 years. If you have kids when you're 30 then your great great great great great grandchildren would be experiencing a daily 9/11 event each and every day of their life. Now take all that death and suffering, and compress it into 6 years. Really puts our modern losses into context.
The point of this is that weapons (or equivalent) capable of immense harm don't necessarily have the impact you might expect. Similarly, get rid of all nukes in the world today while guaranteeing they could not be easily recreated - and you'd likely set in motion a series of actions that would lead to the violent deaths of what could be billions. I find unforeseen consequences endlessly fascinating. Bring on the planet busters. Hope there's nothing we're not foreseeing!
The thing is, there's the time when nobody has nukes, the time when multiple people have nukes and keep each other in check, and the time where one party has nukes. We've got plenty of experience with no nukes and multiple groups with nukes, but had a very short period where one side had nukes. How confident are we that they wouldn't be used much if that period lasted much longer, and the US was less blindsided by the Russian development of nuclear weapons?
I worry less about a future with lots of planet-killer grade weapons than I do about the period where one group has access to them and the others do not. There are any number of ways to justify violence to yourself when you don't have to worry much about the response. For example, preemptively striking before the other side get the same capability because that might lead to another MAD situation which is arguably worse for the species overall...
But after the realization of nuclear weapons, unrestrained war between developed nations simply ended. And we've entered in what is likely the safest and most peaceful 80 years of human existence ever. I realize how absurd that sounds, but statistically it is almost certainly true. It's hard to even imagine the death toll of previous wars. In World War 2, some 3% of the world's population was killed. Today that would be 231 million people. For some scale imagine a 9/11 type event happening, every single day, for 211 years. If you have kids when you're 30 then your great great great great great grandchildren would be experiencing a daily 9/11 event each and every day of their life. Now take all that death and suffering, and compress it into 6 years. Really puts our modern losses into context.
The point of this is that weapons (or equivalent) capable of immense harm don't necessarily have the impact you might expect. Similarly, get rid of all nukes in the world today while guaranteeing they could not be easily recreated - and you'd likely set in motion a series of actions that would lead to the violent deaths of what could be billions. I find unforeseen consequences endlessly fascinating. Bring on the planet busters. Hope there's nothing we're not foreseeing!
[1] - https://en.wikipedia.org/wiki/Cobalt_bomb