Last week’s accidental nuclear fire drill in Hawaii prompted very disparate reactions. Some people abandoned their cars and ran into tunnels for shelter. Others spent their time waiting for death to take them; in fact one person I heard about went to the roof of his hotel to would watch the end of the world.
I believe most people assumed that a nuclear attack by North Korea would immediately kill almost everyone in a city like Honolulu. Their implicit math is simple. If you were standing ¾ of a mile away from the Hiroshima bomb, you have a 50% chance of dying from acute radiation exposure. Since the North Koreans have warheads 10x to 20x more powerful, people imagine that 50% radiation mortality area to be 30 miles across.
The problem is that this math is wrong; the energy of an explosion is dissipated through a three dimensional volume; the radius for any effect goes up only as the cube root of the yield[note 1]. So a bomb that has 20x the yield has only 2.7x the destructive radius. If you want to see what the effect of various size bombs are on specific places, you can visit this site.
Had the Hawaii alert been real, that person who went up on the roof in Waikiki would have died from extensive third degree thermal burns. But had he stayed inside his reinforced concrete hotel he’d probably survive without injury.
Which brings us to this:
We look at “Duck and Cover” as humorously dim-witted today. The idea of covering yourself with a picnic blanket in the event of a nuclear strike seems ludicrous, but it’s important to remember that in 1951 the nuclear arsenal of the Soviet Union consisted of a grand total of five warheads:
So the people who made this film weren’t stupid; circumstances changed. In 1951 a city could expect to receive at most a single aircraft delivered nuclear bomb about twice the yield of the Hiroshima bomb. Sure that picnic blanket wasn’t going to help you if you were at ground zero, but if you were two miles away it could very well enable you to escape serious injury from thermal radiation. Multiply that by tens of thousands of people outside the radius where they’d be killed by ionizing radiation or the shock wave, and it’s not so laughable.
By 1976 this picture had changed: the Soviets had an arsenal of 25,000 nuclear weapons. A city like Honolulu could expected to receive a half dozen or more powerful warheads. The chance of anyone surviving within the city limits would be small, and those that did manage to survive would emerge to dramatic climate effects, widespread radioactive contamination, and the collapse of civilization on a national if not global scale. In that scenario you might as well go up on your roof and get it over with quickly. But we aren’t there yet with North Korea, nor will we be there for a long time. Until we resolve the situation one way or another we are facing the possibility of an attack very much like those envisioned by planners in the early 50s.
And by “we” I mean generations of adults whose sole understanding of what they are facing comes from dystopic fiction like Terminator 2 or Fox News. I had one person in the past week solemnly assure me that radios wouldn’t work after a nuclear attack because of EMP. Not true[note 2]. People I talked to were generally unaware that the most potent radionuclides are short lived, and that the acute fallout risk drops dramatically over the course of 24 hours. This means there actually is a point to sheltering in place for several days.
Is it really acceptable that people facing a situation like this get their information about it primarily from entertainment, scare-mongering propaganda, and hucksters trying to sell them survival gear? Is that moral?
So as obscene as it sounds, maybe it’s time to bring back duck-and-cover type civil defense education.
note 1 — This is a first approximation assuming all things being equal; however reality is somewhat more complex. For example nuclear weapons of various sizes are detonated at various altitudes for maximum effect. The North Koreans also may be uncertain as to the yield of their device. However it is roughly true, which means that casualties go up roughly as the 2/3 power of bomb yield.
note 2 — Nuclear electromagnetic pulse or EMP is a real phenomenon produced by the interaction of nuclear blast gamma radiation with the Earth’s upper atmosphere. Since thermonuclear devices don’t produce nearly as much gamma radiation per yield as smaller single stage atomic bombs, a ground level attack with the North Korean weapon would likely produce few EMP effects. Attacks that would produce the kind of EMP we see in fiction would consist of many small, single stage warheads detonated many miles above the stratosphere. Such an attack would produce no direct ground casualties at all.