And Then You’re Dead book extract: What would happen if you lived in a nuclear winter

THE reality of even a small-scale nuclear war is unimaginable. Even on the other side of the world you wouldn’t be safe.

A nuclear winter would kill millions worldwide. You really don’t want that bomb to go off.

DURING the Cold War it was widely understood that both the United States and the USSR had the capability to destroy the world with nuclear weapons. What people didn’t know was how easily they actually could do it.

Today, thanks to sophisticated weather models built to analyse global warming, we know that even a relatively small nuclear skirmish would be extremely bad news.

Simulations of full-scale war between smaller nuclear-armed countries suggest that a hundred multimegaton bombs would be exchanged, and the simultaneous detonation of a hundred nuclear devices would be bad for you even if you were on the other side of the globe.

Your first problem? Radiation.

When the nukes went off they would irradiate the area and transmute innocuous atoms into dangerous ones. One of the worst of these nuclear bastard children is called strontium-90.

It’s light, so it doesn’t take many explosions for it to coat the globe and get deep into the food supply. Once ingested it’s so similar to calcium that your body absorbs it into your bones.

Children born after the open-air nuclear tests of the 1950s have fifty times the natural level of strontium-90 in their teeth. Fortunately, that’s still below the threshold for serious danger.

Unfortunately, unlike a test, a nuclear battle will blow past that threshold.

Once strontium-90 is in your bones its radioactive decay breaks up the DNA of your cells, leading to bone cancers and leukaemia. So if you survived the initial nuclear exchange, you would have bone cancer to look forward to, but that’s only if you could also survive the more serious smoke, ash, and soot problem.

The second issue, after the dust has cleared from the initial detonations, is that the dust wouldn’t clear. After a hundred multimegaton bombs exploded in the air, not only would they directly distribute carbon into the upper atmosphere but they would start enormous forest and urban fires that would release massive amounts of smoke.

On top of that, the explosions would lift tons of fine dust — all of which would be heated by the sun to rise and collect in the stratosphere.

The smoke from your typical campfire stays below the clouds where it can be wicked away by rain. In the case of nuclear fallout, smoke and ash would be lifted above the clouds where it wouldn’t be wicked away by rain, so it would stay parked for years and block sunlight.

Even conservative environmental simulations show that a hundred nuclear detonations would block enough sunlight to drop the average global temperature by a few degrees. A sudden global drop in temperature of even a couple of degrees would be devastating for the world’s food supply, because a single frost kills rice.

A serious disturbance in rice production would kill as many as 2 billion people around the globe.*

In a hundred-bomb nuclear war nearly a third of the world’s population would die from the explosions, starvation, or cancer, but our species would carry on. In larger, multithousand exchanges of thermonuclear weapons, like the one that almost occurred in November 1983 between the United States and the USSR, however, we probably wouldn’t.

The arsenals of nuclear powers around the world. We don’t want the US and Russia to go to war. Picture: Arms Control Association

HOW CLOSE THE WORLD CAME TO ENDING

On November 7, 1983, the United States led NATO in a massive training exercise called Able Archer that mimicked a nuclear first strike against the USSR. Unfortunately for nearly everybody, the USSR believed the exercise was a cover for an actual first strike.

So in response the Soviets helicoptered missiles to their silos and mobilised their air force, actions that should have alarmed the U.S. military to respond in kind.

Luckily, Lt. Gen. Leonard Perroots of the U.S. Air Force mistook Russia’s actions for a simple training exercise and took no action. That lack of response convinced the USSR to stand down.

Lt. Gen. Perroots made a “fortuitous, if ill-informed” decision, according to declassified analysis of the scare. It might be the most fortuitous mistake in human history.

If the alarm had been raised and the misunderstanding escalated into full-scale nuclear war, a few thousand multi-megaton bombs would have crisscrossed the globe and detonated over their targets.

Even if you didn’t live in a large city (basically every city with a population of more than 100,000 in the United States and the USSR was targeted) and therefore weren’t killed by the initial blasts, you couldn’t expect to live long.

Within two weeks of something like this happening, 180 million tons of smoke, soot, and dust would coat our globe like black paint, and there it would stay.

Light levels would be reduced to a few per cent of what they are today, so high noon would look like predawn. Midsummer highs in North America would be below zero.

The good news is there would be plenty of dead trees to burn for warmth. The bad news: You would starve. Crops would be wiped out, and those that weren’t would suffer from another problem: Bugs.

Cockroaches and their ilk are quite durable when it comes to radiation, but their predators are not. Without any birds to keep them in check, crop-eating pests would prosper. Pests would decimate any crops that made it through the freeze.

But there is an upside (sort of). Cockroaches are actually more efficient than cows at turning grain into protein, and even in the new apocalyptic world there would be plenty for them to eat.

They’re also a healthy snack. Cockroaches are high in vitamin C, protein, and fat, so as long as you’re not a picky eater, you may survive a little longer than expected.

You would just need to eat a lot of cockroaches, around 144 per day, to survive. Gross.

*Global rice production would drop 21 per cent, corn output would decrease by 10 per cent, and soybeans would decrease by 7 per cent, according to an analysis by the International Physicians for the Prevention of Nuclear War.

This is an extract from And Then You’re Dead: A scientific exploration of the world’s most interesting ways to die by Cody Cassidy and Paul Doherty, published by Allen and Unwin and available now.

Paul Doherty is co-director and senior staff scientist at the San Francisco Exploratorium Museum. He received his PHD in solid state physics from MIT.

Cody Cassidy is a writer and editor.

Originally published as And Then You’re Dead book extract: What would happen if you lived in a nuclear winter