You crawl out of the shelter in which you survived, soon finding yourself walking among the ashes. Everything is gone. Everyone is gone. How could something like this even happen? What’s going to happen now?
How do I avoid the fallout?
Well I hate to say it, but you should have stayed inside.
You’ve probably noticed we’re not focusing on specific survival tactics such as preparation and evacuation. There are already plenty of good resources of how to do just that, including Tin Hat Ranch’s excellent youtube series, and the actual US government itself. We’re focusing once again on what happens, and yes, it’s time to address the elephant in the room.
Without a doubt the most culturally well known and terrifying aspect of a nuclear war is the ionizing radiation. Alpha particles (fast moving helium atoms) can be stopped by a piece of paper or your skin, so that’s not much of a problem. Beta particles (fast moving electrons), don’t penetrate much further, being no problem with thick clothing. These can, however, pose a big problem if you eat or drink something contaminated by them.
Gamma radiation is far worse, as it’s made of photons and will go through pretty much anything. For that, you want to put as much mass between you and the source as possible. Lead is ideal (as it’s extremely dense), one gamma halving thickness of lead is only 1 centimeter of lead, and equivalent to 152 metres of air. Even without lead, heaps of any old material will work too. Being underground is best, (9 cm of soil is the same as 1 cm lead) but otherwise just pile everything you can find around your shelter to get as much mass as possible and stay there, at least for the first 48 hours (bring food), because believe me you do NOT want to die from radiation sickness.
If it’s an airburst nuke (which is most likely), congratulations! You’re probably in the clear. These are detonated at an optimized distance above the ground (to maximize destruction) and their radioactive material billows up and away “safely” (more on that later) into the upper atmosphere. If it’s one of these and you’re close enough to be directly irradiated, you’ll be far too busy being killed by the fireball to care about rads.
If it’s a surface detonation (look for solid stem on the cloud) then you’re going to get a massive amount of material irradiated and launched up into the sky. This then “falls out” all over the surrounding area, turning it into a radioactive quagmire. This fallout is extremely dangerous, and needs to be avoided at all costs (i.e. run away) This is very dependent on wind speed and direction too, so make sure to stay upwind whilst fleeing.
If enough cities were hit (particularly with airbursts), the resulting firestorms would almost certainly blanket the sky with ash and smoke, and the radioactive material from all of those detonations would settle globally. This aerosol of soot into the stratosphere could produce an “anti-greenhouse effect”, causing a massive global cooling and darkness of up to 20-30 degrees centigrade, lasting at least a decade. And that was from From US/Soviet models in the 1980s, predictions have only gotten worse since.
There has been LOTS of climate research showing the detrimental effects of a change by only 1 or 2 degrees to global average temperature. 20 degrees is absolutely catastrophic, and would pretty much spell the end for all major civilization. Crop yields will plummet, there’ll likely be mass extinctions for many plant and animal species, and humanity will have a hell of time making it through that winter.
Would this mean extinction for us?
Honestly, I doubt it. This isn’t the first time humans have survived a disaster like this, and while I expect our population will go through the biggest die-off in history, we won’t go extinct altogether. We already weathered the Toba catastrophe, a supervolcano around 70,000 years ago that caused a global winter of up to 10 years, and our present technology and organisation should improve our ability to (hopefully) handle even this.
The human story was never going to end as easily as “and then everybody died”.
The end of our world probably only means the beginning of a cold new one. And for the sake of us all, they had better remember the mistakes of our own.