In the Fallout scenario, the nukes are a generally modest 200-750 kilotons (compared to the Tsar Bomba at a whopping 50 megatons). This massively reduces their blast radius, meaning that there is a smaller area in which you run the risk of being blown into your own shadow, but it does mean that, rather than the radioactive material being thrown up into the stratosphere, it spreads through the lower atmosphere before their relatively short half-lives render them harmless, treating everybody within a 25 miles radius to a deadly dose of radiation.
Anyway, using these figures to calculate how many you would need to wipe out both China and the United States, an area of nearly 10 million square miles, you would need about 422,000 nukes to flatten it. As we learnt earlier, even at the height of the Cold War, there were only 66,000 nukes on the planet, but if we take into account that the Cold War never ended in Fallout and factor in continued production, we get 218,556 nuclear weapons.
Still not enough.
But hold up. The 422,000 figure assumes that the population is spread out evenly across the land mass, which is just not how humans distribute themselves, we tend to densely populate certain areas. This makes popping to the shops easier, but also makes us sitting ducks for weapons of mass destruction.
Given the population distribution of both countries, our new figure come out at just 15.8% of our original estimate ... or 66,676. For those of you playing along at home, that is the number of nukes that actually existed at one point.
So, with this massively reduced figure, the number of nuclear weapons that existed in the Fallout universe would have been enough to wipe out not just the American and Chinese populations, but the rest of the world too.
Turn out it's not so far fetched after all. Better get digging that bunker.
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