I’m old enough to remember the duck-and-cover drills at school when I was a kid. Even in the first grade I can remember wondering how a desk would protect me against a nuclear explosion – at some point I just assumed that the adults must know more than I so I’d climb under my desk with everyone else, pretending that the school was collapsing around me. We’ve got away from the duck-and-cover days of my youth, but since it’s the fiftieth anniversary of the Cuban Missile Crisis, a little musing on nuclear annihilation seems appropriate.
There’s no need to go into the details – the Cuban Missile Crisis is one of the better-documented geopolitical crises of the Cold War days. The important thing is that, had the crisis devolved into a nuclear exchange, it is quite likely to have been catastrophic – in addition to the radioactive fallout from hundreds to thousands of megatons of nuclear explosions the explosions would have filled the skies with dust and debris; combined with the smoke from hundreds or thousands of massive fires the Earth would have been blanketed in a shroud of almost impenetrable haze that would almost certainly have kicked off a nuclear winter. Between the loss of major centers of population, a great deal of our critical infrastructure, and likely crop failures and mass starvation it is not unreasonable to speculate that a large-scale nuclear war could well have meant the end of 20th century civilization – it could well have pushed us back, if not to the Stone Age, at least to pre-electrical days.
What impresses me about the Cold War days is that we lived with the possibility of all of this for nearly a half-century – with the near-constant possibility that even a small electronic glitch or military miscalculation could destroy centuries or millennia of progress – and in spite of that not only did we manage to have fairly normal lives, but we restrained ourselves from using our deadliest weaopns. In spite of having tens of thousands of warheads mounted on missiles, bombers, and submarines – all on hair-trigger alert – and in spite of the occasional false alarms (all seasoned with more than a smattering of distrust) we never launched our weapons. Our civilization – and humanity itself– survived and the Cold War ended without a nuclear exchange.
So now let’s fast-forward to the present. We know that we continue to face the threat that a nuclear weapon will be detonated in anger – possibly in an India-Pakistan nuclear war, possibly by North Korea, or maybe by a terrorist organization. And while there is no denying that any such detonation will be horrible, it is unlikely to cause civilization’s end. An attack with one or two nuclear weapons, devastating as it would be, would not threaten all of civilization and would certainly not kick off a nuclear winter. In addition, the fallout from a single nuclear device in the kT range would be far less than that of even a single thermonuclear weapon, let alone hundreds or thousands. Devastating as an act of nuclear terrorism might be for the city (or cities) attacked, it would be a far cry from what we practiced for in my grade-school classes. Thus, ironically, while we might be closer to seeing a nuclear attack today than at any time in several decades, the world might actually be safer today than it was during the Cold War.
The other topic I wanted to touch on is also related to the use of nuclear weapons – the little-studied impact of mass fires (what used to be called a firestorm). A fascinating 2006 book (Whole World on Fire) by author Lynn Eden details the impact of mass fires that result from nuclear weapons and discusses the fact that American nuclear war planning more or less ignored their effects. While much of the book addresses the organizational reasons for this apparent oversight, what I’d like to take a quick look at is what these mass fires might do.
First of all we need to all be on the same page as to what a mass fire is. The thermal pulse from a nuclear weapon will ignite fires out to several miles from the point of detonation. A multitude of small fires will coalesce into a single mass fire that will consume nearly 100% of the combustible materials within its perimeter. The fire itself will consume so much oxygen that even those who are shielded from the heat will likely die of oxygen deprivation. The rising plume of superheated air draws more air in from the sides – on the one hand this makes a mass fire almost impossible to extinguish as long as there is any remaining fuel; on the other hand the rush of incoming wind helps keep the fire from spreading out laterally once it begins making its own weather. Incidentally, I should also mention that mass fires can be started by conventional means – the Allied fire-bombings of Dresden and Tokyo also initiated mass fires that (in the case of Tokyo) were every bit as deadly as the nuclear bombings in Hiroshima and Nagasaki.
Were a 10 kT nuclear device to be set off the mass fires would engulf everything with a half mile or so of the site of the attack – a square mile or so of terrain. This might not sound like much, but consider how much can be squeezed into a square mile. For example, in New York City this radius would encompass everything from Battery Park to City Hall, pretty much from river to river (Hudson to East River, that is). During the working day there are upwards of a half-million people in this area – more than in all but a handful of entire US cities.
Nuclear response planning today considers the effects of radiation, blast, flash blindness, and even broken glass but it pays scant heed to mass fires. Considering the huge potential impact, it could be that they should also be part of our nuclear emergency response planning.