So in this scenario everybody over the age of fifteen years has suddenly died of an unknown cause (I don't think it's relevant, but not an infectious disease).

The event refers to the deaths of all over 15.

The situation:

  • Everybody over the age of 15 years all die instantly at the same time
  • This is a one time event, so people won't die when they turn 15
  • The event starts in the near future, so no technology that we do not have now

I'm interested in what people think:

  • What the immediate aftermath would be
  • The aftermath after a few years (8-10)
  • The situation after about 30 years
  • And how long it would be until society and technology reach the level we're at today (if ever)

This idea was sparked by The Enemy series by Charlie Higson.

  • 4
    $\begingroup$ It would probably take a while for your question to be answered. /sarc $\endgroup$
    – Frostfyre
    Jun 5, 2017 at 17:10
  • $\begingroup$ Immediate aftermath: Everyone over the age of 15 is dead. After a few years: Most of the dead have decomposed/been picked clean by carrion-eaters. How long until soc & tech reach the level of today: Anything from 30 years to 30 millennia $\endgroup$
    – dot_Sp0T
    Jun 5, 2017 at 17:14
  • 1
    $\begingroup$ @sphennings - not a duplicate. The other question was, essentially, "What if people stop aging?". Here the situation is much more dramatic. $\endgroup$
    – Alexander
    Jun 5, 2017 at 17:27
  • $\begingroup$ True but unhelpful @dot_Sp0T $\endgroup$ Jun 5, 2017 at 19:08
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    $\begingroup$ @Friendlysociopath - because the Earth is round, it's not that important :) $\endgroup$
    – Alexander
    Jun 5, 2017 at 20:26

6 Answers 6


Sorry, I totally missed the "one time event" thing. So, the humanity will live.

In the immediate aftermath, older children will join warring clans, while most of the young children will die. There will be no need for activities like farming and manufacturing, since scavenging and looting would be far more profitable. Largest clans can try to establish some sort of stability, with justice and law enforcement.

In 10 years, clans will turn into mini-kingdoms that will have established borders, laws and stable populations. The success of those kingdoms would be mostly defined how successful the initial groups were at securing weapons and supplies in the first year. This is when people will start turning from using stored food to farming. There still will be plenty of fuel and equipment to use, but maintenance would be becoming an issue.

In 30 years, people will start reviving old industries, making fuel and replacement parts for aging machinery. The scenery would still be post-apocalyptic, but with bright outlook.

In 100 years, civilization should recoup the losses and get on par with today's technology, even if population would be smaller.

//////Humankind may not survive.

Age of 15 is perhaps past the breaking point for the survival of human species. For natural reproduction to replenish the population, every female should have 2 children + extra (to cover for mortality and infertility within the rest of population). Even with onset of puberty is getting earlier today, childbirth is still a problem for young moms. Without access to quality maternity care and c-sections, I assume that miscarriages, infant and maternal mortality would be quite high. That can push the rate of required pregnancies over 3.

If addition, there would be no older population, not even one wise and experienced person for all of the young ones.

My prediction that after the initial dying the remnants of the population will get reduced to savagery and finally die off in less than 30 years.

  • $\begingroup$ you focus greatly on having children here which is not going to be greatly relevant with a timescale of a few years, i'm more interested in what societies and groups people think appear $\endgroup$ Jun 5, 2017 at 18:16
  • $\begingroup$ There's 2.3B people on Earth under the age of 15. That's orders of magnitude more than even the most conservative critical population levels. $\endgroup$
    – Mazura
    Jun 5, 2017 at 18:44
  • $\begingroup$ I don't know where to look for numbers on this, but I'd expect any survivors from still-extant hunter-gatherer groups to be Just Fine, and there should be enough of them that the species survives, even if everyone from an agricultural or industrial background dies off. $\endgroup$
    – zwol
    Jun 5, 2017 at 18:50
  • $\begingroup$ this answer is really good now you've edited it👍 $\endgroup$ Jun 5, 2017 at 18:57
  • $\begingroup$ I suspect that a large percentage of women/children giving birth would die if.... only people 15 and younger survived. Two children per woman might not be enough.. $\endgroup$
    – enderland
    Jun 5, 2017 at 19:12

This doesn't look good.

The immediate effects:

I found an estimate that at any given time, there are roughly 19 million drivers on the road at any given time. Given that all (or at least the overwhelming majority) of them will be 15 or over, That's 19 million cars in the US alone suddenly veering out of control at houses, buildings, power poles, pedestrians, each other, you name it. About half of that many passengers will be riding along, so even if they're not raptured due to age, things don't look pretty for their future.

Many kids/teenagers will die when a car comes crashing through the wall, when another car collides with theirs, or when they get outright run over on the sidewalk. Power poles go down.

Some kids/teenagers will die when the surgeons operating on them do, others will die when that gorilla whose enclosure they climbed into at the zoo has nobody to shoot it. People carrying heavy things will drop them, some of these might roll and cause injury, death or infrastructure damage.

Now how does our infrastructure look?

Actually worse than the sudden deaths suffered by out-of-control cars, highways become impassible from the sheer volume of wreckage strewn about. Bonus points if the event struck at rush hour. Neighborhoods are without power, and probably some parts of urban areas too. In the most extreme cases, perhaps a delicate operation was underway at a power plant or two and now power has been lost totally for a large population.

Most of the population was without income to begin with, and the rest are now both very short on customers and managers. As funds run out, the automated systems that manage electrical access turn off the utility in large quantities accross the board... supposing anyone lives that long.

The guy who reads emails and fulfills orders for grocery store stocking is gone now, so distribution of food is kaput. Even those distributors who automate this have no truck drivers to fill the orders. Even if there were, the roads are completely impassible from wrecked cars. Nobody will make the order to producers, but then again there are very few producers left anyway.

Running water is probably ok though. Most of those companies still rely on workers manually shutting off the utility. So not many will be dying of thirst until water towers run dry. I guess that's a plus.

So who fixes all this?

Kids and teenagers will probably prove much more resourceful than adults would expect, but even so many of the positions that are most crucial in our infrastructure require specialized education or training that most of the survivors would not have. Perhaps a few uncannily-minded individuals would fill some gaps but overall the skills simply won't exist to remedy most of these problems.

So where does that leave us?

We're back to hunting and gathering within weeks or even days. Many of our youth will no doubt be fine with hunting until the ammunition runs out. With enough ingenuity, some kids and teenagers will be able to survive anyway. In an ironic twist of predator-prey curves, despite the large amount of prey, there are too few predators among the survivors. Those less capable will flock to those more capable. Limited resources (the prey) cause contention and conflict. The population isn't sustainable and drops rapidly.

As more and more fall back on ancient methods of survival or die outright, even those equipped with the skills to uphold infrastructure are left with nobody to uphold it for.

So we're all dead?

Some survivors might squeak by when all is said and done by making an effort to isolate themselves immediately and having the skills to survive. Perhaps they can find enough resources to provide for themselves and a friend or two. So I guess we're not all dead...

  • $\begingroup$ The harambe reference is mean $\endgroup$ Jun 5, 2017 at 20:16
  • $\begingroup$ not at all....kids are stupid $\endgroup$
    – Evi
    Jun 5, 2017 at 20:43
  • $\begingroup$ Oi....only some kids are stupid @Evi $\endgroup$ Jun 5, 2017 at 21:17

This is almost certainly an extinction level event.

If you consider that anyone under the age of 4 needs constant supervision just to keep from hurting/killing themselves...

...and then realize that 25% of your surviving population need that constant supervision...

...then add in the total loss of all medical, food-production, food-preservation, and sanitation knowledge...

...and finish it off with diseases rising from the 4-6 rotting corpses for every surviving soul. @Alexander is too generous. I give humanity 3 years, max.

...and finish it off by handing command of our society over to a bunch of untrained, idealistic 15 year-olds, just entering the emotional turmoil of teenage life. It will be a wild party while it lasts, but that wouldn't be very long... I'm still betting on extinction.

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    $\begingroup$ My estimate assumed that some children communities will have access to shelter, equipment and food that can last for very long. For "children in the wild" scenario, the time is indeed much shorter. $\endgroup$
    – Alexander
    Jun 5, 2017 at 17:47
  • $\begingroup$ I agree that some communities will provide basic necessities for a while, but those places would probably have a higher corpse count and therefore bigger problems with disease. I think it all evens out and becomes completely un-survivable pretty quickly. If the OP raised the death age by a few years, some of the survivors would be strong enough to move and bury their dead. I think that would be enough to invalidate my answer and make your (also pretty depressing) answer the correct one. $\endgroup$ Jun 5, 2017 at 17:53
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    $\begingroup$ I still beg to disagree. We don't need many children to survive, just some, to give humanity a bit of a chance. In my scenario, all it takes is a group of children reaching a far suburban/rural warehouse (there are plenty of those in developed countries). There, isolated from the diseases, and having all that they need, children community can survive for years. 12-14 years olds are smart enough and strong enough to bury the dead. $\endgroup$
    – Alexander
    Jun 5, 2017 at 18:02
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    $\begingroup$ Corpses do not spread diseases. Every forest is full of dead birds, mice, rabbits, etc., and their corpses get eaten by other animals without problem. Even the bodies of victims of ugly diseases like ebola are only infectious if you stay in very close contact. $\endgroup$
    – Karl
    Jun 5, 2017 at 20:08
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    $\begingroup$ @AmbroseWinters, Now that is a story that I would read! A Disney cruise ship with all the staff and parents dead and no outside world coming to rescue them. A self sufficient environment with plenty of supplies and a easy method of corpse disposal... "Parent, overboard!" I still don't think it would be a long story, but between the ironic backdrop and eventual calamitous ending (when they try to dock the boat somewhere)... it would be a great read! $\endgroup$ Jun 5, 2017 at 20:33

It's estimated that 26.9% of the global population is 15 or younger in 2017. While you say it doesn't matter how such a unlikely, if not impossible, event happens, since it is basically a magical/supernatural event, I'm not so sure. I agree with the comments which state that many, if not most, of the youngest would die. I don't have any idea what the mortality rate would be, but if we assume the working age population is 16 to 70, and if we assume that approximately that proportion of the population would be needed to support the rest then the numbers are: 68% are currently working age and there are 360 million age 13,14, & 15. Assuming those are the entire new workers, that would limit the population to about 530 million out of the 2 billion, meaning roughly 75% of the survivors would die, with the majority coming from the youngest ages.

There are undoubtedly many 15 year olds today who have the mental competency of an adult. What would be lacking is emotional stability and experience. I have zero clear idea whether peasants in rural 3rd World countries would be more likely to survive than kids in the 1st World, but I suspect they would. Meaning the population would shift towards rural and 3rd World. But would that be important? Their global or even regional "reach" would be quite limited. My guess is that while it's possible that within few years several Genghis Khans/Alexanders/Napoleons might appear, it's more likely that such conquerors would require establishment of stable (agrarian) economies followed by city states followed by regional powers.

In other words, I'd expect it to take several generations, if not centuries, for the establishment of a steampunk semi-industrial warring nations global scenario. Fertility would obviously take a hit, but since birth control would be back to rhythm and barrier methods, I'd expect the birth rate to rapidly sky-rocket over the first 10 years. So, the first couple of years would probably be all about survival - both developing food sources and developing some sort of military. (I restrict my comments to regions where the economic potential is well above subsistence level hunting/gathering/herding/agriculture.) These would be the years of the big die off (from 2 billion to 400 to 600 million).

The first decade would see establishment of local economic activity, followed by both the beginnings of regional trade and regional conflicts. By 30 years, I'd expect the world to basically be in a continual state of war - but at a low intensity.

It's interesting to speculate what the collapse of Industrial Civilization will do to the climate, but it's too dependent on the personalities of the conquerors.

So, the near-term consequences, which was your question, would basically be similar to any other apocalypse. Mostly survivors trying to figure out how to feed themselves. I think you'd have (again, ignoring extremely poor, extremely rural areas) the rapid formation of small local "tribes" (gangs). The ones who dominate will be, at first, the ones who control the guns, later it will be the ones who are able to field the largest army. Such governing structures are likely to be rapacious and therefore unstable, it will take a generation or two for stable hierarchies to develop, I'd guess.

How long till they are "back" to here? Well, considering our population isn't sustainable, maybe never, but considering our species inability to exercise discipline and act on their own best interests, as well as our preoccupation with sex, I'd guess less than 150 years but more than 75 years.

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    $\begingroup$ Can you format this wall of text a little? It is hard to read like this. $\endgroup$ Jun 5, 2017 at 19:33

Immediate problems

You have a couple of immediate problems after your death-event. At time=0, suddenly, all or nearly all automobiles, ships, airplanes, military vehicles, etc. are suddenly operating without an operator. This will result in a huge mess. Crashing cars and planes cause fires and injure children.

You have no fire department. You have no doctors or nurses or EMTs or police. So by the next day, most cities are going to face real threats from fires. Anyone who was already hurt or gets hurt in the initial chaos has no way to get better. Rescue efforts will be poorly planned or executed, as the rescuers lack the training to plan and coordinate logistics.

Short-term problems

No one knows how to do Anything anymore. This is only a slight exaggeration. Almost no one at or below the age of 15 in a 1st world country has any idea how to do day-to-day survival tasks beyond household chores. They don't know how to restore servers, set broken bones, treat brain or spinal injuries, operate construction equipment safely, build to-code shelters, run power grids, run water or internet or cellphone or other grids, etc. Within weeks, the lights would go out and may well stay out.

How many youth today really understand how to grow crops? Or how to midwife? Child mortality and death during child birth will rise quite high. And starvation and malnutrition will be equally devastating.

Rural areas of extreme poverty will likely suffer comparatively less than urban areas, as people in these areas tend to be more self-sufficient and learn how to survive at an earlier age. Urban areas, be it 1st, 2nd, or 3rd world will be deadly for anyone. No one living in urban environments will have access to food after the first week or two. This will put pressure on surrounding communities, as people escape the urban areas.

Long-term problems

Libraries and bookstores have books, but those books are only part of the knowledge transferred from teacher to student at each point along the educational pathways. Those pathways were destroyed. So much institutional knowledge, trade knowledge, etc. is gone. The collapse that started at the day of destruction and worsened throughout the short-term will lead you into a rather frightening Dark Ages. No one knows how to make medicines, build cars, repair electrical grids, launch communications satellites, predict weather, or build storm shelters.

Once the lights go out, the internet is no longer available, both speeding up and worsening the coming Dark Age.

It will be centuries before civilization recovers to technological levels like the early 20th century.

Quite frankly, I'm glad I'm in my 40s and wouldn't have to face this nightmare.

  • $\begingroup$ "Almost no one at or below the age of 15 in a 1st world country has any idea how to do day-to-day survival tasks beyond household chores." The question was referring to a global event, not just limited to the Western Hemisphere. $\endgroup$ Jun 5, 2017 at 19:58

My own view on the question is that immediately after everybody died there would be a surge of gangs looting and enjoying the loss of any rules.

After a year or so settlements of people would have appeared with the weaker but more intelligent in charge, starting growing crops and farming animals.

After an extended period of time (10 years) i think humanity will be back into the iron age with little to no medicine and disease meaning death.

But i Think overall humanity will eventually relearn how to farm, get minerals, build machines and eventually get back to where we are now. With books being a huge contributing factor.

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    $\begingroup$ I somehow doubt that we'll lose all knowledge just because over 15s die. Libraries, books still exist, and knowledge is there to be absorbed. Read a book and you can learn how to do pretty much everything except bleeding-edge technology and research $\endgroup$ Jun 5, 2017 at 19:21
  • $\begingroup$ School is out forever and you expect kids to go to the library? $\endgroup$
    – Devsman
    Jun 6, 2017 at 14:02
  • $\begingroup$ @Devsman Only the clever ones who release that they learn the skills or die $\endgroup$ Jun 6, 2017 at 15:05

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