Nine or so months ago, I was working with Tom McCabe on a Palo Alto-based SIAI-funded research project that covered topics such as catastrophic risk, biotechnology, artificial intelligence, and intelligence enhancement. A segment of the research involved looking for quantitative estimates of the probability of general nuclear war between the Soviet Union and the United States during the Cold War. It was very difficult to find any (why aren’t experts ever forced to at least come up with quantitative guesses?), but we had a few — JFK famously estimated the likelihood of general nuclear war during the Cuban Missile Crisis at between 33% and 50%.

To explore the topic further, Tom met with Professor Emeritus Martin Hellman. Hellman has studied nuclear risk for decades and gave the present risk of nuclear war as 1% annually. In a 2008 paper, he outlined nuclear near misses and compiled estimates others had given.

Eventually we moved on to other topics, but Tom mentioned a book to me: Nuclear War Survival Skills by Cresson Kearny, an infantry reserve lieutenant and scientist who apparently spent a fair amount of time in the jungles of Central America with a machete in hand. Kearny was a pioneer in improving the strategies and equipment for the US Army operating in jungles, and was awarded the Legion of Merit for his work.

It wasn’t until a few months later that I read Nuclear War Survival Skills, and I was extremely impressed by the book. I would say it had the most surprises out of any book I’ve read in the last year. It turns out that the vast majority of bomb shelters built around the world during the Cold War would have been completely ineffective if there actually were a danger of fallout, due to inadequate ventilation:

Because of the worldwide extreme fear of radiation, civil defense specialists who prepare official self-help instructions for building shelters have made radiation protection their overriding objective. Apparently the men in Moscow and Washington who decide what shelter-building and shelter-ventilating instructions their fellow citizens receive – especially instructions for building and improving expedient shelters-do not understand the ventilation requirements for maintaining endurable temperature/humidity conditions in crowded shelters. It must be remembered that shelters may have to be occupied continuously for days in warm or hot weather.

Russian small expedient shelters are even more dangerously under-ventilated than are most of their American counterparts, and can serve to illustrate similar ventilation deficiencies of American shelters. Figure 6.5 is a Russian drawing (with its caption translated) of a “Wood – Earth Shelter” in a Soviet self-help civil defense booklet, “Anti-Radiation Shelters in Rural Areas.” This booklet, published in a 200,000- copy edition, includes illustrated instructions for building 20 different types of expedient shelters. All 20 of these shelters have dangerously inadequate natural ventilation, and none of them have air pumps. Note that this high-protection-factor, covered-trench shelter depends on air flowing down through its “Dust Filter with Straw Packing (hay)” and out through its small “Exhaust Duct with Damper.”

As part of Oak Ridge National Laboratory’s participation in Defense Nuclear Agency’s “Dice Throw” 1978 blast test, I built two Russian Pole- Covered Trench Shelters. These were like the shelter shown in Fig. 6.5, except that each lacked a trapdoor and filter. As anticipated, so little air flowed through these essentially dead-ended test shelters that temperatures soon became unbearable.

The issue of ventilation of shelters has been so poorly addressed in official documents that the author had to invent an expedient air pump, the Kearny Air Pump, to fill the need. Official attention to this crucial detail has been all but absent for the last 50 or more years.

Because of the apparent lack of attention to the crucial issue of ventilation, hundreds of thousands or even millions of lives could be lost in the aftermath of a general nuclear war because of people being forced to leave their shelters due to unbearable heat. If we bothered to spend billions of dollars to build fallout shelters, why did we neglect the issue of ventilation? Because of irrational fear over radiation from fallout. As Kearny points out in the book, fallout particles are mostly dangerous if they get into your food or water — in most cases, tiny fallout particles will not have enough radioactive material to radiate very intensely or for long. Even in areas with the heaviest fallout, leaving the shelter for a 20-30 seconds to check a water supply should not be too dangerous. There is a myth that any degree of radiation can kill instantaneously. Like AI, most people’s knowledge about the physics of nuclear weapons and radiation comes from Hollywood science fiction.

It gets worse: according to Kearny, many civil fallout meters can only measure levels of radiation far too low for practical use in a post-attack situation. Here was his experience with some commercial fallout meters:

Used and surplus dose rate meters and dosimeters are likely to be inaccurate or otherwise unreliable. Very few buyers have access to a radiation source powerful enough to check instruments for accuracy over their full ranges of measurements. My education regarding bargain fallout meters began in 1961, after I bought two dosimeters of a model then being produced by a leading manufacturing company and purchased in quantity by the Office of Civil Defense. Within a week after receiving these instruments, one of them could not be charged. The other was found to be inaccurate. Later I learned that the manufacturing company sold to the public its instruments that did not pass Government quality tests.

As Kearny explains, having an accurate fallout meter in the aftermath of a nuclear attack is pretty much a necessity. But so few of them exist and those that do may be unreliable. He comes to the rescue again, however, with plans for an ingeniously designed expedient fallout meter.

The book has many other extremely valuable suggestions for use during a post-attack situation. After having read the book, I’ve started to think that the chance of survival with this knowledge would be much, much higher than without it. Especially in the most hard-hit areas, where large ground-level explosions throw up a lot of fallout.

Besides being useful in the aftermath of a potential nuclear war, the book lets us know what to expect in the opening moments of an attack, as well as common myths about nuclear weapons and radiation. Here’s a portion about what to expect in an initial attack:

The great majority of Americans would not be injured by the first explosions of a nuclear attack. In an all-out attack, the early explosions would give sufficient warning for most people to reach nearby shelter in time. Fifteen minutes or more before big intercontinental ballistic missiles (lCBMs) blasted our cities, missile sites, and other extensive areas, most citizens would see the sky lit up to an astounding brightness, would hear the thunderous sounds of distant explosions, or would note the sudden outage of electric power and most communications. These reliable attack warnings would result from the explosion of submarine-launched ballistic missiles (SLBMs). These are smaller than many ICBMs. The SLBM warheads would explode on Strategic Air Command bases and on many civilian airport runways that are long enough to be used by our big bombers. Some naval bases and high-priority military command and communication centers would also be targeted.

The vast majority of Americans do not know how to use these warnings from explosions to help them save their lives. Neither are they informed about the probable strategies of an enemy nuclear attack.

Nuclear bombs only vaporize a relatively small area. Like Indiana Jones, who survives a nuclear explosion in the most recent movie by jumping into a refrigerator (that part could actually be realistic!), people outside ground zero might survive a nuclear blast if they are not directly exposed to the thermal pulse and are not in front of a window or hit by flying debris. In Hiroshima and Nagasaki, there were home-made, soil-based blast shelters near ground zero that survived completely intact, but they were mostly unused. (The authorities and citizens did not know that a single incoming Allied plane posed such a profound threat.) Kearny points out that many casualties in a nuclear attack might be due to people running to windows in major cities, looking at the sky lit up by SLBMs, only to be killed by blades of glass when otherwise-survivable ICBMs explode.

I don’t think that general nuclear war is a hugely probable risk: I’d give it a 20% probability of occurring over the next 40 years, taking into account the probability of accidents where China/Russia/France/Britain/USA think one of the others is attacking them and retaliate too hastily. What I do think is interesting, however, is how woefully unprepared we would be if a nuclear war did occur. The difference between 50 million casualties and 100 million casualties could be simply a matter of knowing simple facts like 1) fallout shelters are necessary, 2) ventilation is necessary, 3) have a small store of water and food ready, 4) avoiding radiation poisoning is more important than having more than a small meal a day, 5) a fallout meter is a necessity, 6) treat injuries with “benign neglect”, 7) there is enough grain storage to feed the whole country for two years even if all crops are ruined, etc.