You mentioned the successful SM-3 intercept test in 2020. While it’s true it managed to intercept an “ICBM-representative target”, and can be based from ships anywhere they sail (thus posing a major potential threat to the Chinese/NK deterrent in the future), I don’t know if I (or the US military) would call it a meaningful operational capability yet. For one we don’t even know its success rate. The more mature (and only other) system with ICBM intercept capability, the Ground-Based Interceptor, has barely 50%. [1] I’m not sure what you meant by “sending it to Europe”[2] because US Navy Aegis ships carrying the SM-3 interceptors would have to be positioned close to under the flight path to intercept Russian ICBMs in midcourse flight. That’s the weakness of a midcourse BMD strategy, and why China is developing things like Fractional Orbital Bombardment which lets them fire an ICBM at the US from any direction, not just the shortest one, to avoid overflying sea-based midcourse interceptors. The thing is because Russian ICBMs would likely fly over the North Pole the ships would probably have to be in the Arctic Ocean, which I’m unsure is even practical due to ice there etc. Anyway there’d be no hope of intercepting all the hundreds of ICBMs, even ignoring Russia’s SLBM force which can be launched from anywhere in the world’s oceans.
That’s all to say, I don’t see how that’s a possible event which could happen and be escalatory? Of course if the US could do something in Europe which would actually threaten Russia’s second strike capability that would be massively destabilizing, but they can’t at this point. [3] Russia’s deterrence is quite secure, for the time being.
I basically agree with Graubard’s estimate, btw. But, I mean, 3/5% is still a lot...
Edit: I’m not sure who mentioned the 60% probability of successful detonation over London after launch, but that’s absurd? Modern thermonuclear warhead designs have been perfected and are extremely reliable, very unlikely to fail/fizzle. Same goes for delivery systems. The probability of successful detonation over target conditioning on launch and no intercept attempts is well over 95%. London doesn’t even have a token BMD shield to speak of, while Moscow is at least protected by the only nuclear-tipped ABM system left in the world.
There are lots of other details. Both GMD/GBI and Aegis BMD/Aegis Ashore are mainly intended to defend against crude ICBMs like those from NK, Russian/Chinese ones carry lots of decoys/penaids/countermeasures to make midcourse interception much harder and thus their success rates lower. Plus the claimed rate is in an ideal test environment, etc.
Perhaps you meant construct more Aegis Ashore facilities? But there would have to be an AWFUL lot constructed to legitimately threaten the viability of Russia’s deterrent, plus it would take tons of time (far, far longer than sailing a few Aegis destroyers over) and be very visible, plus I’m unsure they could even place them close enough to the northward flight trajectories of Russian ICBMs as mentioned to intercept them.
Also, not sure where best to post this, but here’s a nice project on nuclear targets in the US (+ article). I definitely wouldn’t take it at face value, but it sheds some light on which places are potential nuclear targets at least, non-exhaustively.
tll;dr: The 60% was because I didn’t really know much about the AMB capabilities early on and gave it around a 50-50. I updated upwards as we researched this more, but not by that much. This doesn’t end up affecting the aggregate that much because other forecasters (correctly, as it now seems), disagreed with me on this.
Hey, thanks for the thoughtful comment, it looks like you’ve looked into ABM much more than I/(we?) have.
The 60% estimate was mine. I think I considered London being targetted but not being hit as a possibility early on, but we didn’t have a section on it. By the time we had looked into ICMBs more, it got incorporated into “London is hit given an escalation” and then “Conditional on Russia/NATO nuclear exchange killing at least one person, London is hit with a nuclear weapon”.
But my probability for “Conditional on Russia/NATO nuclear exchange killing at least one person, London is hit with a nuclear weapon” is the lowest in the group, and I think this was in fact because I was thinking that they could be intercepted. I think I updated a bit when reading more about it and when other forecasters pushed against that, but not that much.
Concretely, I was at ~5% for “Conditional on Russia/NATO nuclear exchange killing at least one person, London is hit with a nuclear weapon”, and your comment maybe moves me to ~8-10%. I was the lowest in the aggregate for that subsection, so the aggregate of 24 micromorts doesn’t include it, and so doesn’t change. Or, maybe your comment does shift other forecasters by ~20%, and so the aggregate moves from 24 to 30 micromorts.
Overall I’m left wishing I had modeled and updated the “launched but intercepted” probability directly throughout.
You mentioned the successful SM-3 intercept test in 2020. While it’s true it managed to intercept an “ICBM-representative target”, and can be based from ships anywhere they sail (thus posing a major potential threat to the Chinese/NK deterrent in the future), I don’t know if I (or the US military) would call it a meaningful operational capability yet. For one we don’t even know its success rate. The more mature (and only other) system with ICBM intercept capability, the Ground-Based Interceptor, has barely 50%. [1] I’m not sure what you meant by “sending it to Europe”[2] because US Navy Aegis ships carrying the SM-3 interceptors would have to be positioned close to under the flight path to intercept Russian ICBMs in midcourse flight. That’s the weakness of a midcourse BMD strategy, and why China is developing things like Fractional Orbital Bombardment which lets them fire an ICBM at the US from any direction, not just the shortest one, to avoid overflying sea-based midcourse interceptors. The thing is because Russian ICBMs would likely fly over the North Pole the ships would probably have to be in the Arctic Ocean, which I’m unsure is even practical due to ice there etc. Anyway there’d be no hope of intercepting all the hundreds of ICBMs, even ignoring Russia’s SLBM force which can be launched from anywhere in the world’s oceans.
That’s all to say, I don’t see how that’s a possible event which could happen and be escalatory? Of course if the US could do something in Europe which would actually threaten Russia’s second strike capability that would be massively destabilizing, but they can’t at this point. [3] Russia’s deterrence is quite secure, for the time being.
I basically agree with Graubard’s estimate, btw. But, I mean, 3/5% is still a lot...
Edit: I’m not sure who mentioned the 60% probability of successful detonation over London after launch, but that’s absurd? Modern thermonuclear warhead designs have been perfected and are extremely reliable, very unlikely to fail/fizzle. Same goes for delivery systems. The probability of successful detonation over target conditioning on launch and no intercept attempts is well over 95%. London doesn’t even have a token BMD shield to speak of, while Moscow is at least protected by the only nuclear-tipped ABM system left in the world.
There are lots of other details. Both GMD/GBI and Aegis BMD/Aegis Ashore are mainly intended to defend against crude ICBMs like those from NK, Russian/Chinese ones carry lots of decoys/penaids/countermeasures to make midcourse interception much harder and thus their success rates lower. Plus the claimed rate is in an ideal test environment, etc.
Perhaps you meant construct more Aegis Ashore facilities? But there would have to be an AWFUL lot constructed to legitimately threaten the viability of Russia’s deterrent, plus it would take tons of time (far, far longer than sailing a few Aegis destroyers over) and be very visible, plus I’m unsure they could even place them close enough to the northward flight trajectories of Russian ICBMs as mentioned to intercept them.
Not for lack of trying since the dawn of the arms race. Thermonuke-pumped space x-ray lasers, bro.
Also, not sure where best to post this, but here’s a nice project on nuclear targets in the US (+ article). I definitely wouldn’t take it at face value, but it sheds some light on which places are potential nuclear targets at least, non-exhaustively.
Thanks!
tll;dr: The 60% was because I didn’t really know much about the AMB capabilities early on and gave it around a 50-50. I updated upwards as we researched this more, but not by that much. This doesn’t end up affecting the aggregate that much because other forecasters (correctly, as it now seems), disagreed with me on this.
Hey, thanks for the thoughtful comment, it looks like you’ve looked into ABM much more than I/(we?) have.
The 60% estimate was mine. I think I considered London being targetted but not being hit as a possibility early on, but we didn’t have a section on it. By the time we had looked into ICMBs more, it got incorporated into “London is hit given an escalation” and then “Conditional on Russia/NATO nuclear exchange killing at least one person, London is hit with a nuclear weapon”.
But my probability for “Conditional on Russia/NATO nuclear exchange killing at least one person, London is hit with a nuclear weapon” is the lowest in the group, and I think this was in fact because I was thinking that they could be intercepted. I think I updated a bit when reading more about it and when other forecasters pushed against that, but not that much.
Concretely, I was at ~5% for “Conditional on Russia/NATO nuclear exchange killing at least one person, London is hit with a nuclear weapon”, and your comment maybe moves me to ~8-10%. I was the lowest in the aggregate for that subsection, so the aggregate of 24 micromorts doesn’t include it, and so doesn’t change. Or, maybe your comment does shift other forecasters by ~20%, and so the aggregate moves from 24 to 30 micromorts.
Overall I’m left wishing I had modeled and updated the “launched but intercepted” probability directly throughout.
Thanks again for your comment.
Thanks that is useful and interesting! (re: edit — I agree but maybe at 90% given some uncertainty about readiness.)