Let's assume that:

  • the entire nuclear arsenal available on earth is launched and detonated, completely obliterating civilization but leaving a few humans and animals in very remote areas alive.

  • this creates a 50 year long nuclear winter almost completely blocking sunlight and rendering photosynthesis impossible (I'm not sure if ~20,000 nukes would be enough to achieve this but let's pretend it is).

  • these remote areas have levels of radiation that are low enough for some of the survivors to not die of radiation poisoning/cancer during those 50 years

  • the survivors have access to enough potable water to survive 50 years

  • the pool of animals that survived is too small for human survivors to rely solely on hunting for 50 years

  • the reserves of pre-apocalyptic conserved food (canned food, for example) are too small for human survivors to rely solely on them for 50 years

  • there are not enough human survivors for them to rely solely on cannibalism for 50 years

Would it be possible in that environment for survivors to not starve and feed themselves throughout the 50 year long nuclear winter?

I'm not asking about complex lifeforms in general or issues with the oxygen/CO2 cycle as that would be too broad although surival of humans obviously depends on that.

I'm pretty sure some bacteria and microorganisms would survive, maybe some insects too. Mushrooms would probably survive too.

I'm not sure if humans can survive on a diet only consisting of mushrooms and cockroaches though. How do you think those poor survivors will feed themselves?

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    $\begingroup$ Scavenge for a few years, then a nomad existence, cannibalism, and extinction. $\endgroup$
    – LSerni
    Commented Jan 30, 2018 at 7:20
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    $\begingroup$ They would starve. That's what makes nuclear winter such an interesting setting. But I guess you want them to live? $\endgroup$
    – Mołot
    Commented Jan 30, 2018 at 7:24
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    $\begingroup$ You might want to look at how long it'll take for the oxygen to run out if all photosynthesis stops? Will the air be breathable for 50 years? $\endgroup$
    – Doomfrost
    Commented Jan 30, 2018 at 8:17
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    $\begingroup$ @Doomfrost Back of envelope calculation: clearly breathable. If all living organism were turned in to CO2, then the carbon dioxide levels would raise something like 5-6 times en.wikipedia.org/wiki/Carbon_cycle while volcanic production is 1/1000 of contemporary CO2 level livescience.com/40451-volcanic-co2-levels-are-staggering.html $\endgroup$
    – Shadow1024
    Commented Jan 30, 2018 at 11:53
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    $\begingroup$ Don't eat the glowing yellow snow. $\endgroup$
    – T.E.D.
    Commented Jan 30, 2018 at 18:45

8 Answers 8


If they cooperate they would be fine. They could set up hydroponics on a big scale before their food ran out. Supplement their diet with the fast growing crops and expanding however they can, they have plenty of power they can use. I assume trees died, but wood is still a fuel and there are a LOT of trees.

A lot of them would die, those that banded together in an intelligent attempt to survive and expand would be OK, some of them at any rate.

You have the humans only surviving in remote places. Fact is remote places are actually the best set up for survival many times. Because the people there need to have a range of suitable skills since they do most things for themselves, they would also have stores of fuel and more likely to have emergency equipment such as generators, canned food, tools etc,. They're also used to cooperating in terms of looking after each other and sharing skillsets. City dwellers are a different story entirely.

I live on an island prone to cyclones. I have a generator, fuel, first aid kit, and big water tank, I could right now, without rationing, live a couple of months cut off with my kids and wife on stored supplies. But whole remote communities would be much better organised. I'm not a survivalist, this is normal assets for anyone here who can afford it.

As a comment suggests, you have at least 2 years to work it out. The earlier you start preparing the better.

I like comforts and lights so electricity is important. You could covert trees and water to steam.... you could make hydrogen from water..... you could just do the muscle powered generator trick... or you could use a water wheel or windmill to generate power, that's off the top of my head, but if I had a few years and my life and my kids lives depended on it, I'd work it out.

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    $\begingroup$ Trees are really hard to convert to electricity, and on mechanics stack people say gasoline stays fresh up to 2 years, so you have heat, and 2 years of light covered. Maybe 5. What about the remaining 45~48 years of light you need? $\endgroup$
    – Mołot
    Commented Jan 30, 2018 at 8:21
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    $\begingroup$ With the complete blackout there will be, I expect winds to kind of go to a halt aswell. You will have some, but I don't know if that is enough to power a wind turbine. Maybe ocean / geothermal electricity? Maybe I'm completely wrong and it would actually increase winds, dunno. $\endgroup$ Commented Jan 30, 2018 at 15:31
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    $\begingroup$ Nuclear power of course! $\endgroup$
    – Rob Rose
    Commented Jan 30, 2018 at 15:49
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    $\begingroup$ @Mołot while it's probably a bad idea to store gasoline multiple years in a canister and then use it in your car, it's most definitely not the case that all liquid hydrocarbon fuels are only storable for two years, nor 50 years. In fact I don't see a reason you couldn't store even gasoline for centuries in a really big, solid, well-sealed tank; it will probably not be very fine quality afterwards, but surely would burn just fine. $\endgroup$ Commented Jan 30, 2018 at 16:34
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    $\begingroup$ @RonJohn It doesn't matter, the more remote someone lives the more self sufficient they need to be $\endgroup$
    – Kilisi
    Commented Jan 30, 2018 at 19:50

Governments have already prepared for this. See the Svalbard Seed Vault.

As long as people cooperate and don't start killing each other, people should be able to start up hydroponics farms.

While hydroponics requires quite a lot of electricity, that shouldn't be as much of a problem as you'd think. While power plants in some countries may be primary targets, it is not practical for nuclear weapons to destroy every single piece of infrastructure in every single country. Iceland, for example, runs over a quarter of their nation off of geothermal power and almost all of the remainder comes from hydro power.

  • $\begingroup$ +1 Very difficult but feasible. As long as you keep nuclear or fuel power plants running, you can grow crops indoors. $\endgroup$
    – Pere
    Commented Jan 30, 2018 at 17:07
  • $\begingroup$ You're planning to do that farming under lights? Because there won't be useful sunlight for years. $\endgroup$ Commented Jan 31, 2018 at 1:28
  • $\begingroup$ I would recommend wind turbines for your electricity. Unlikely to all be damaged beyond repair. The technology is easy to build and repair (although new build will be much lower efficiency and output than current designs). Issues about variability are not an important for growing plants, can scale more easily than large power plants, no need to go mining fuel, and little expertise needed. Large power plants also require electricity to start, so may not even be viable to turn them on. $\endgroup$
    – Scott
    Commented Jan 31, 2018 at 1:56
  • $\begingroup$ True. One thing I didn't think of though is spare parts, which wing turbines need a lot of. $\endgroup$
    – Rob Rose
    Commented Jan 31, 2018 at 2:08


We could kill every living thing on land, but we would hardly make a dent in the ocean (with nukes).

Fishing ships are more likely to survive the war, since most of the time, they are at sea, away from the blasts.

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    $\begingroup$ If photosynthesis stops, the oceans die. $\endgroup$
    – ceejayoz
    Commented Jan 30, 2018 at 15:19
  • $\begingroup$ I agree both with you and @ceejayoz. From one hand, most food chains are based on phytoplankton which obviously depends on sunlight. All phytoplankton will be eaten for, say, decade. On the other hand, there are different types of plankton which probably could reproduce without sunlight. It would be great to improve answer by adding info about chemoautotrophs and food chains based on them. $\endgroup$
    – ADS
    Commented Jan 30, 2018 at 15:54
  • $\begingroup$ Even in a nuclear winter, the sky wouldn't get matrix-ed. Photosynthesis would still occur, I think. $\endgroup$
    – user47242
    Commented Jan 30, 2018 at 15:55
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    $\begingroup$ Also, beyond the food chain collapsing due to the loss of photosynthesizing phytoplankton, if the sun is blotted out to some degree, a lot of ocean life is also really sensitive to temperature change. $\endgroup$ Commented Jan 30, 2018 at 15:59
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    $\begingroup$ @James I agree, but OP's question specifically states "completely blocking sunlight and rendering photosynthesis impossible". $\endgroup$
    – ceejayoz
    Commented Jan 30, 2018 at 16:02

The survivors would try to live from hunting and scavenging of preserved food in the safe areas. As you say, there's not enough food for everyone, so after a while they will start to starve. Some of them will resort to steal from those better-off, some will resort to cannibalism, but most of them will just venture out of the safe zones into the irradiated areas, looking for food - and fleeing from other humans.

The radiation background in those zones will have reduced to just a thousandth of what it was the day of the end of the world, so the explorers will do just fine. Sure, many of them will develope some cancer in twenty or thirty years, but its life expectancy would be way lower in a place without food, so who cares?

Even if only 0.001% of the food is edible, it will be more than enough to feed the little human population that's left. We all have a lot of food at our homes, plus there's a lot of in supermarkets and stores. Those who died in the armaggedon never lived to eat it, and whatever animals or survivors didn't eat in the very first months it's going to be frozen. There will be also a lot of unprocessed food available: frozen vegetables in the fields, frozen animals (though most of them would have died of starvation and so they aren't going the best source of protein)... even frozen humans, if they are so desperate to resort to cannibalism - they should focus on those who commited suicide, to exclude disease.

  • $\begingroup$ Beware that nuclear winter isn't instantaneous. When corpses get frozen they will have been rotting for weeks, at least - although radiation could be somehow a preserver. $\endgroup$
    – Pere
    Commented Jan 30, 2018 at 15:25
  • $\begingroup$ I know. As a matter of fact the main source of food would be the usual food that you can buy in the supermarket whose owners died in the blast. I'm going to edit my answer to make that clear. $\endgroup$
    – Rekesoft
    Commented Jan 30, 2018 at 16:45
  • $\begingroup$ Except those supermarkets almost certainly burned, either in the war itself or because there wasn't any fire protection and a fire from elsewhere burned them. $\endgroup$ Commented Jan 31, 2018 at 1:27
  • $\begingroup$ @LorenPechtel Maybe. As I say, even if only 0.001% of the food that was available before the war is still there (and still edible), that's plenty of food for these scavengers. The largenumbers law works on their side. $\endgroup$
    – Rekesoft
    Commented Jan 31, 2018 at 9:14
  • $\begingroup$ I would expect far more survivors than food to survive. Plenty of people will be between cities when the bombs fall. $\endgroup$ Commented Feb 2, 2018 at 4:33

TLDR Yes, it's possible to survive. Those who starve will die and optimal number of people will be reached. But probably it will take more than 50 years.

As @RealSubtle noted, mushrooms and some fishes probably don't ever notice that there is no sunlight anymore. Another important thing is new generations.

Nobody will stop reproducing. 50 years is enough for 2-3 people generations. Animals, plants will spawn too. Sure, most of them will die - but it's usual for wild life. And only most adapted will survive. The story about black and white moths shows that wild nature could adapt even to fast changes. Nuclear winter is extremely fast change of environment but it also trigger faster adaptations due to radiation-provoked mutations.

Although there is no sunlight and many old food chains would be broken, a new species will spawn and many just adapt. The higher animal in food chain, the less changes need to adapt. For example, mushrooms and lichens will enjoy new conditions (dead trees/animals, cold weather) and could replace grass/trees (total extinction, grass has almost no chances). Reindeers eats both lichens and grass so they supersede cows (cows have chance to adapt but it take ages). Predators like wolves and bears just change diet from cows to reindeers. People are top predators which have ultimate adaptation resource - their brains - so they are definitely could survive. UPDATE As @leftaroundabout mentioned, lichens are photoautotrophs. They are more primitive and less effective compared trees. But they adapted to hard environment and could grow where grass can't. Like dark moths, they already exist and just widespread and supersede in new conditions.

The amount of food will reduce significantly so less people creatures could live on the same area. Starvation and battles for best areas are just regulators of population. Less adapted will die and most adapted will eat as much as they needed. Again, it's usual for wild nature.

From perspective of evolution, the 50 years is too small period. Probably a new features/behaviour would be developed but don't fixed in a whole species. I doubt that food chains would be stabilized in that period. In fact, the wildlife is not a stable system. It's better to say that new species will conquer new areas even after 50 years.

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    $\begingroup$ Lichen won't enjoy these conditions: unlike fungi (but like algae and plants), they live on photosynthesis. $\endgroup$ Commented Jan 30, 2018 at 16:52
  • $\begingroup$ The story about black and white moths is not a case of Hollywood Evolution. Moths are already adapted to environmental colour change, the most efficient gene is simply expressed more often (due to them surviving more). The evolution itself happened at a much slower pace, a long time ago. $\endgroup$
    – Eth
    Commented Jan 30, 2018 at 17:48
  • $\begingroup$ @leftaroundabout sure, my point is they are more adapted to hard environment. As James pointed out, small part of sunlight will still here. I updated answer to clarify $\endgroup$
    – ADS
    Commented Jan 30, 2018 at 18:21
  • $\begingroup$ @Eth That's why I said that 50 years is not enough for evolution. But already existing organisms will replace <s>a place in the sun</s> old ones. For example, hemobacteries and fungi are less effective for now and therefore less spread. And could be more effective after nuclear war - as black moths become more effective. I updated my answer with hope it more clear now $\endgroup$
    – ADS
    Commented Jan 30, 2018 at 18:27

If they are lucky enough to be near a cave which has a population of blind fish big enough to eat then they could start breeding them.

For mushroom cultivation, they would need access to plant materials. This would not be a problem if they live near a forest. Even if the trees die due to not being able to photosynthesise, they would be probably well-conserved by the cold to last 50 years for a small human colony. Although they would probably need to use them for heating too.


Funny timing that I just read this question, as I just read the book "The Knowledge: How to Rebuild Civilization in the Aftermath of a Cataclysm" by Dr. Lewis Dartnell. This is a reference book, not a fiction book. In it, he is targeting a certain kind of post-apocalyptic scenario similar to yours, and he even mentions that it could be nuclear-winter-driven.

The interesting correlation here is that Lewis Dartnell speaks of a similar level of survived humans, and he proposes that the humans who are left could survive for an estimated 55 years just by raiding the pre-existing food around them, first the perishable foods then proceeding in order of ever less perishable foods.

I am not sure how Dr. Dartnell came to his estimate of 55 years of food per person in his scenario which was similar to yours, but he did contact many experts in various fields and did much research, so I would assume that he is probably correct at least to within an order of magnitude, and I will take his estimate as our baseline assumption.

I do not know if that estimate takes into account what the recently deceased people would have eaten before they died. If not, that might need to be reduced somewhat. But even if that is the case, you should be able to procure other foodstuff somewhere to augment that. Some others have suggested fishing, which should be viable for some time. Fungus will be quite happy to feast on the decaying life for a while. You can get seeds to begin growing with little or no light so that they absorb some extra nutrients from the ground, then eat them as sprouts. Using indoor grow-lamps could produce a small, supplemental amount to keep you alive with the other things. So I will stick with the 55 year estimate and suggest it could be even more.


You asked for 50 years. There is an estimated (at least) 55 years of food around you that you can use despite the nuclear winter. So yes, they should survive. They will eat mostly what is left behind from pre-apocalypse, and they will supplement it with fishing and fungus early on, later on with seeds and low-light sprouts and a few grow-lamp-fed whole plants. I suggest kale, as it is quite hardy and nutritious.


There will be enough preserved, canned food available to survive for some months, maybe years. During this time the survivors will need to get a solid supply of electricity going. Wind and water turbines will still function quite well. The survivors will need to locate themselves where there are waterfalls and height differences, and build lots of water powered turbines/dynamos. This would require quite some engineering skills to get established. It might be possible for some knowledgeable folk to use an existing hydroelectric station, or tap into some existing wind farm.

They will set up farms under electric lights. Given enough energy production I don't see why they couldn't grow a variety of crops. Hydroponics are effective, but not necessary, normal dirt will still work as normal dirt after a nuclear apocalypse.

The farms might be planted as normal, outdoors, but would require a scaffolding or rig structure around them to hold the lights. There is a risk of radioactive contamination from the environment, so it might be better to scrape an inch or two of the topsoil off before beginning a farm. Rndioactive dust would probably blow in eventually though. Might not be too bad, survivors will have to take chances.

Radioactive contamination could greatly be reduced by building farms underground, maybe in a subway tunnel, but the temperature would be an issue preventing many crops from thriving. Should be ok for mushrooms and bug farms though.


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