Liberation Day Minus 7700: Log #10 The fatal flaw in nuclear deterrence.

Note that, as of now, there are only seventy-seven hundred days remaining until Liberation Day, 6 August 2045.

IF… If Mutually Assured Destruction were strictly mutual, then the threat of nuclear-in-kind retaliation might be credible and thus effective. The problem is: it’s not strictly mutual, it’s blatantly global. This flaw is rarely discussed in depth and, to the best of my knowledge, is never written about.

I gave a presentation about it to a gathering of diplomats in Geneva two decades ago. My talk followed presentations by Alan Robock and Ira Helfand on the environmental and health impacts of a ‘limited’ nuclear war. This was when ‘nuclear winter’ was experiencing a revival due to the results of qualitatively superior climate modeling techniques. My talk was entitled, “Deterrence in Tatters”.

With a small dose of trepidation, I now put this down in writing. Those in the position to use nuclear weapons are almost certainly aware of this flaw. It is only fair that the public at large is in-the-know as well.

Thomas C. Schelling and Morton H. Halperin* wrote the “handbook” on the game theory of nuclear deterrence. They identified over a dozen rungs on the nuclear escalation ladder. There were two hidden assumption of their work: (1) that the consequences of escalation were borne primarily by the two adversaries (per above), and (2) that the rungs on the ladder were rather evenly spaced, i.e. that escalation could increase linearly at least on the lower rungs.

Both of these assumptions are blown out of the water by the nuclear-winter findings. When firestorms inject one hundred Hiroshima-equivalent amounts of soot into the troposphere (i.e. above the stratosphere) decades-long impacts are felt worldwide. Not least, the capacity to cultivate food is radically reduced making it impossible to sustain even a fraction of today’s world population.

Given that today’s Bombs and cities are much larger than 1945-Hiroshima, a mere score (that word again!) of metropolises subjected to the most common, 300-kiloton detonations would, very likely, trigger catastrophic climate disruption (CCD). What has not been (publicly) investigated is whether ten such attacks would also be sufficient; presumably not. In other words, we don’t really know where the threshold is.

Why does this matter?

Compared to the number of such weapons actually deployed and primed for use, a score is a mere pittance. In short, each side knows that triggering CCD is well within the capacity of even the ‘minor’ nuclear powers. As nuclear escalation starts up the ladder, this raises two existential questions: (1) who is going to sustain the most damage to cities short of the threshold, and (2) who is going to blow past the threshold?

Taking the second question first: after a dozen of one’s major cities have been incinerated, retaliating in kind would leave Mutually Assured Destruction behind and bring on globally assured destruction. The great majority of humanity, not just your adversary, would suffer grievously; indeed, all one’s friends and allies, not to mention further severe suffering of one’s own people.

If, for the sake of argument, this is enough to “self-deter” then the first question takes on a heightened urgency. Does one allow one’s adversary to gobble up the sub-threshold metropolis-targets, or does one hit a dozen or so of the adversary’s cities first, saddling their leadership with the mutual/global dilemma?

You can see how this might seriously tempt a leader to escalate promptly toward, but short, of the threshold.

Granted, if self-deterred from incinerating more cities (despite a dozen of one’s own laying in ashes), there would still be the option of retaliating against nonflammable targets. But most “strategic value” targets are located in or near cities. A 300 kiloton Bomb detonation at the outskirts of a metropolis would still ignite a firestorm in a portion of the city, equivalent to, say, two Hiroshimas (instead of five). So, only a half-dozen such retaliatory attacks would already be risking crossing the threshold to global CCD. All other nuclear attacks would have to be confined to remote areas (of diminishing strategic value). The only consolation being that the same would be true for one’s adversary.

The first takeaway from this is that the vast bulk of the superpower’s nuclear arsenals are at best grossly redundant, at worst geo-suicidal.

The second takeaway is that there is a profoundly destabilizing escalation incentive built into nuclear deterrence if cities are targets (See (3) next). Nuclear armed military leaders know this; I would hope the civilian leadership knows it; the public is in the dark. As you were until you read this.

The third takeaway is the pivotal role of cities, the world’s largest accumulations of flammable materials. Nuclear attack not only causes grievous injury, it adds the insult of transforming in a day what was once an engine of prosperity into a layer of soot high in the sky depriving those below of life-giving sunlight.

How I wish this were the whole story. High-altitude electromagnetic pulse (HEMP) is yet another, somewhat less well kept, dirty secret. You have perhaps heard of “the fog of war”. Imagine being thrown back to the pre-electronic era without carrier pigeons and the Pony Express ready to pick up the slack! That will be a subject of a subsequent log.

*To Mort’s great credit (unlike Thomas) he was among the first to advocate no-first-use policies and he has stuck to it to this day. For background, his last official position was United States Director of Policy Planning (1998–2001).