I'm working on an idea for a story. It takes place in the somewhat distant future, say 200-300 years. Some time between now and then, an event occurs which causes all computers to simultaneously fail. This event is NOT the result of terrorism or malice, it is more or less, an accident. (specifically it is caused by a well-intentioned AI that is less powerful than expected and cannot withstand the strain of all the tasks it is given)

For the purposes of the story, I want this event to greatly reduce the population of Earth, and also effectively put an end to most or all major cities. I don't want it to threaten extinction, just reduce the number of humans by some large percentage (a lot of leeway here).

My problem is, I'm not sure what we could rely on so heavily that would cause this much destruction. I imagine that the following thing would happen all nearly simultaneously:

  • Complete failure of power grid
  • Meltdown of all nuclear power plants
  • High-tech farming equipment no longer functions or malfunctions
  • Traffic lights, streetlights, trains, subways all either fail or malfunction

How much actual damage would these failures do? Would these things alone be enough? What other consequences could there be?

EDIT for clarity: I am not looking for something that would cause technology to fail, I am looking for the effects of loss of all technology and how it would reduce the human population.

  • $\begingroup$ Welcome to Worldbuilding.SE prushik, glad you found us. We have a tour and help center you might wish to check out. $\endgroup$
    – Cyn
    Sep 14, 2019 at 20:14
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    $\begingroup$ Learning the effects of loss-of-technology is easy: Turn off the electricity to your flat for a week or so - enough for a laundry cycle. No cheating by using your phone. Walk down to the store and buy a newspaper to learn what's happening. Buy fresh food every day because you don't have refrigeration. Drudge for an entire day doing your laundry once a week. Pay for everything in cash. Go to bed at sunset. If you get sick or a toothache...tough. If you go someplace that uses electricity, don't use it - that would be cheating. $\endgroup$
    – user535733
    Sep 14, 2019 at 20:40
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    $\begingroup$ Still very difficult from your question to determine what would be a best answer to give. Bearing in mind every home appliance would fail. Maybe security fail-safes included. Maybe the majority of the population would get locked into their homes/offices/cars/entertainment pods and die of dehydration. How can we know unless you are specific about how the world is in 200-300 years. Tell us about how your world works, then we (maybe) can help. $\endgroup$ Sep 14, 2019 at 20:42
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    $\begingroup$ Most nuclear power plants can't melt down not even if you try to make them. $\endgroup$
    – John
    Sep 14, 2019 at 20:43
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    $\begingroup$ Your biggest killers by far will be starvation and lack of medical attention. you are talking about complete infrastructure collapse. $\endgroup$
    – John
    Sep 14, 2019 at 20:45

3 Answers 3


The answer to this is actually much more mundane than you might think:

Food Supply

Keeping cities fed, watered, and clean is a masterpiece of logistics. Agriculture, food processing, and delivery is all carefully coordinated to bring thousands of tonnes of food into major cities daily. You don't need high-tech tractors to fail to induce widespread starvation, just having the delivery databases go away would be sufficient to kill millions.

Then, of course, as food rots where it's delivered in excess or lies undelivered, you have food riots, as starving people break into places rumoured to have food. This destroys more infrastructure, breaks up society, and encourages pestilence in its wake.

It's a very real "for want of a nail" situation that could happen at any point.

In the wake of the food supply failing, other logistics/manufacturing would fail as well. Depending on the urban population density, the death toll could be in the billions, worldwide.

As a side note...

Of the points you mention, "Nuclear meltdown" is the least likely. As has been explained on this site many times, abrupt failures of various systems in nuclear power plants leads to the plant either shutting down or permanently safeing itself unless something catastrophic (earth quake, bombing, tsunami) happens to the structure of the plant.

Most nuclear plants, even lacking their computers, would just quietly shut down forever, rather than melt down.

  • $\begingroup$ Thank you. This seems to be the best answer. Although, yes, it is more mundane than I had hoped, and slower.. I think I can make this work in my story, since this would have a much bigger impact on cities than rural areas, which is what I was looking for. And I realize based on this and other comments that I have to throw out the idea of meltdowns. $\endgroup$
    – prushik
    Sep 17, 2019 at 1:03
  • $\begingroup$ @prushik - glad to help! Remember to mark the answer as "accepted" if it's the one you choose. $\endgroup$
    – jdunlop
    Sep 17, 2019 at 1:06

I'm not sure if this helps, but in case you have not read it yet, there is a book called The World Without Us, by Alan Weisman. There we learn how long the nuclear plants and buildings will last if there are no humans left (they disappeared from one day to the next) to maintain them. Since your story is about the sudden loss of technology, some of the consequences should be similar or the same as the scenario of the sudden disappearance of humans (and there are probably a list of beneficial sources he used to write it).

But if this takes place a couple of hundred years from now, I'm assuming the technology have evolved, which would affect society in a way it doesn't today.

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    $\begingroup$ Thank you, I looked in to this book a little bit, Although the situation doesn't quite match what I am looking for, there are definitely some good and helpful ideas. I was looking for more shorter term, but Alan Weisman seems to cover much longer term. However, based on feedback other from this question, it seems I will need to adjust my story to have a longer and slower apocalypse... $\endgroup$
    – prushik
    Sep 16, 2019 at 2:30

Well one easy thing would be artificial wombs. If people are mostly grown in tanks and therefore probably all sterilized the loss of tech would mean that the next generation is going to be very small and the population crash happens non violently.

Even short of this the failure of medical infrastructure is going to have an impact. No more robot doctors or pill factories is gonna kill a lot of people. Also the possibility of the failure of containment systems could mean something like smallpox is released again and kills huge numbers.

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    $\begingroup$ I'm not seeing how this answers the question. $\endgroup$
    – Mark
    Sep 17, 2019 at 2:15
  • $\begingroup$ This would seem to fall into the category of unsuccessful frame-challenge, whilst what you suggest might work it's not likely to be a solution that the OP will adopt. $\endgroup$ Mar 23, 2021 at 21:09

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