My understanding is that the warning systems are generally designed such that the ICBMs could launch before the attacking warheads reach the silos. I do have significant probability on counterforce scenarios, but I can’t rule out counter value scenarios, so I think it’s an important question to estimate what would happen in these counter value scenarios.
Even leaving aside the ICBMs, “countervalue” was one of McNamara’s weird theories, and definitely wouldn’t be implemented as a pure thing. If nothing else, a lot of those warheads are going after military targets, not cities.
Other people have probably done more rigorous analyses now, but my rough estimate in 2015 was that 1500 nukes to the US would destroy nearly all the suburb area of 100,000+ population metro areas.
Maybe if they were targeted specifically with that goal in mind, but again, that seems unlikely, particularly with modern guidance systems. You’ll do better for yourself shooting at specific things rather than asking “how many civilians can we kill”? A lot of those will be far away from cities, or will have overlap with something else nearby that is reasonably hard and also needs to die.
In reality, there is significant dilution, but another fire model generally found the smoke going to the upper troposphere (the Lawrence Livermore National Lab study).
I might be misreading it, but that paper seems to bury a lot of the same assumptions that I’m objecting to. They assume a firestorm will form as part of the basis of how the fire is modeled, and then explicitly take the 5 Tg of stratospheric soot per 100 fires number and use that as the basis for further modeling. For other fuel loadings, the amount of soot in the stratosphere is linear with fuel loading, which is really hard to take seriously in the face of the “wildfires are different” assertion. Sure, they accurately note that there are a lot of assumptions in the usual Turco/Toon/Robock model and talk a good game about trying to deal with all four parts of the problem, then go and smuggle in the same assumptions. Points for halving the smoke duration, I guess.
Edit:
I would think the non-deployed warheads could just be stored deep underground so they would nearly all survive.
Deep bunkers like that are expensive and rare, and even if the bunker itself survived, ground bursts are messy and would likely leave it inaccessible. Also, there’s the problem of delivering the warheads to the target in an environment where a lot of infrastructure is gone. Missile warheads are only of use as a source of raw materials, and while you might be able to get gravity bombs to bombers, you wouldn’t get many, and probably couldn’t fly all that many sorties anyway. It’s a rounding error, and I’m probably being generous in using that to cancel out the loss of deployed warheads. (Why do we keep them, then, you ask? Good question. Some of it is in case we need to up deployed warheads quickly. A lot is that various politicians don’t want to be seen as soft on defense.)
Deep bunkers like that are expensive and rare, and even if the bunker itself survived, ground bursts are messy and would likely leave it inaccessible.
There are thousands of underground mines in the US (14000 active mines, but many are surface mines), and I think it would only require 1 or a few to store thousands of nuclear weapons. Maybe the weapons would be spread out over many mines. It would not be feasible to make thousands of mines inaccessible.
Missile warheads are only of use as a source of raw materials, and while you might be able to get gravity bombs to bombers, you wouldn’t get many, and probably couldn’t fly all that many sorties anyway.
Are you saying that missile warheads could not be quickly configured to be used as a gravity bomb? I’m not claiming that most of the non-deployed nuclear weapons could be used in a few days, but I would think it would be feasible in a few months (it would only take a few surviving bombers if the warheads could be used as gravity bombs).
OK, remember that we’re dealing with nuclear weapons, which inspire governments to levels of paranoia you maybe see when dealing with crypto. Dropping a dozen nukes down a mine somewhere is not going to happen without a lot of paperwork and armed guards and a bunch of security systems. And those costs don’t really scale with number of warheads. Sure, if you were trying to disperse the stockpile during a period of rising tension, you could take a few infantry companies and say “hang the paperwork”. But that requires thinking about the weapons in a very different way from how they actually do, and frankly they wouldn’t be all that useful even if you did do that, because of the other problems with this plan.
Are you saying that missile warheads could not be quickly configured to be used as a gravity bomb?
Yes, I am. The first commandment of nuclear weapons design since 1960 or so has been “it must not go off by accident”. So a modern missile warhead has an accelerometer which will not arm it unless it is pretty sure it has been fired by the relevant type of missile. And trying to bypass it is probably a no-go. The design standard is that one of the national labs couldn’t set a US warhead off without the codes, so I doubt you can easily bypass that.
it would only take a few surviving bombers if the warheads could be used as gravity bombs
A modern bomber is a very complex machine, and the US hasn’t set ours up to keep working out of what could survive a nuclear exchange. (This is possible, but would require mobile servicing facilities and drills, which we do not have.) Not to mention that they can’t make a round-trip unrefueled from CONUS to any plausible enemy, and the odds of having forward tankers left are slim to none.
I might be misreading it, but that paper seems to bury a lot of the same assumptions that I’m objecting to. They assume a firestorm will form as part of the basis of how the fire is modeled, and then explicitly take the 5 Tg of stratospheric soot per 100 fires number and use that as the basis for further modeling.
For reference, here is what they say about their fire modelling:
The goal of the fire simulations in this work is to better characterize the spatial and temporal distribution of smoke from a mass urban fire resulting from a 15 kt nuclear detonation. Therefore, our modeling is informed by the Hiroshima firestorm, and the Hamburg firestorm, due to its rough similarity to the Hiroshima firestorm in size and duration. The assumption that all 100 detonations cause fires, and that these fires are more like the Hiroshima firestorm than Nagasaki, is a worst-case scenario. The studies of Penner et al. (1986) and Toon et al. (2007) also use fire parameters based on these historical cases (Hiroshima and Hamburg), so our fire parameters have the additional benefit of being similar to these previous studies. To produce simulations of fires similar to Hiroshima and Hamburg, it is assumed that the terrain is flat (i.e., topography does not provide shielding of thermal radiation) and there is uniform fuel loading over the area where thermal radiation is sufficient to ignite standard construction materials, such as wood. The WRF model source code is modified to allow for specification of surface fluxes of heat, water vapor and smoke (or black carbon), requiring quantification of these three fluxes, as well as the fire shape, size and duration.
The Hiroshima firestorm burned an area of about 11 to 13 km2 in 4 to 9 h, taking 20 to 30 min to develop into a firestorm (Glasstone, 1962; Rodden et al., 1965). The Hamburg firestorm burned a comparable 12 km2 in about 6 h (Carrier et al., 1985). Therefore, we specify a circular area with a 2 km radius (12.57 km2) for our fires. Each fire has a 30 min ramp-up period as surface fluxes increase linearly from zero, followed by a 4 h fire duration where surface fluxes are constant. The 4 h duration is chosen because it is the shortest time estimate for the fire in Hiroshima, and releasing a given mass of emissions and burning a given fuel amount over the shorter time period will result in higher smoke concentrations and heat fluxes, thus providing a worst-case estimate.
Even leaving aside the ICBMs, “countervalue” was one of McNamara’s weird theories, and definitely wouldn’t be implemented as a pure thing. If nothing else, a lot of those warheads are going after military targets, not cities.
Maybe if they were targeted specifically with that goal in mind, but again, that seems unlikely, particularly with modern guidance systems. You’ll do better for yourself shooting at specific things rather than asking “how many civilians can we kill”? A lot of those will be far away from cities, or will have overlap with something else nearby that is reasonably hard and also needs to die.
I might be misreading it, but that paper seems to bury a lot of the same assumptions that I’m objecting to. They assume a firestorm will form as part of the basis of how the fire is modeled, and then explicitly take the 5 Tg of stratospheric soot per 100 fires number and use that as the basis for further modeling. For other fuel loadings, the amount of soot in the stratosphere is linear with fuel loading, which is really hard to take seriously in the face of the “wildfires are different” assertion. Sure, they accurately note that there are a lot of assumptions in the usual Turco/Toon/Robock model and talk a good game about trying to deal with all four parts of the problem, then go and smuggle in the same assumptions. Points for halving the smoke duration, I guess.
Edit:
Deep bunkers like that are expensive and rare, and even if the bunker itself survived, ground bursts are messy and would likely leave it inaccessible. Also, there’s the problem of delivering the warheads to the target in an environment where a lot of infrastructure is gone. Missile warheads are only of use as a source of raw materials, and while you might be able to get gravity bombs to bombers, you wouldn’t get many, and probably couldn’t fly all that many sorties anyway. It’s a rounding error, and I’m probably being generous in using that to cancel out the loss of deployed warheads. (Why do we keep them, then, you ask? Good question. Some of it is in case we need to up deployed warheads quickly. A lot is that various politicians don’t want to be seen as soft on defense.)
There are thousands of underground mines in the US (14000 active mines, but many are surface mines), and I think it would only require 1 or a few to store thousands of nuclear weapons. Maybe the weapons would be spread out over many mines. It would not be feasible to make thousands of mines inaccessible.
Are you saying that missile warheads could not be quickly configured to be used as a gravity bomb? I’m not claiming that most of the non-deployed nuclear weapons could be used in a few days, but I would think it would be feasible in a few months (it would only take a few surviving bombers if the warheads could be used as gravity bombs).
OK, remember that we’re dealing with nuclear weapons, which inspire governments to levels of paranoia you maybe see when dealing with crypto. Dropping a dozen nukes down a mine somewhere is not going to happen without a lot of paperwork and armed guards and a bunch of security systems. And those costs don’t really scale with number of warheads. Sure, if you were trying to disperse the stockpile during a period of rising tension, you could take a few infantry companies and say “hang the paperwork”. But that requires thinking about the weapons in a very different way from how they actually do, and frankly they wouldn’t be all that useful even if you did do that, because of the other problems with this plan.
Yes, I am. The first commandment of nuclear weapons design since 1960 or so has been “it must not go off by accident”. So a modern missile warhead has an accelerometer which will not arm it unless it is pretty sure it has been fired by the relevant type of missile. And trying to bypass it is probably a no-go. The design standard is that one of the national labs couldn’t set a US warhead off without the codes, so I doubt you can easily bypass that.
A modern bomber is a very complex machine, and the US hasn’t set ours up to keep working out of what could survive a nuclear exchange. (This is possible, but would require mobile servicing facilities and drills, which we do not have.) Not to mention that they can’t make a round-trip unrefueled from CONUS to any plausible enemy, and the odds of having forward tankers left are slim to none.
Thanks for the engagement, David and Bean!
For reference, here is what they say about their fire modelling: