# What would a post-nuclear-war Earth actually look like? [closed]

Many popular depictions of the aftermath of a nuclear war show the entire Earth as a sort of desert - hot, irradiated, cratered, with deformed animals scrounging around and generally quite bleak. This is evocative stuff, but I'm looking to make a realistic post-WW3 scenario, and I can't imagine the world would actually look like Fallout or Mad Max after a nuclear war - after all, Hiroshima and Nagasaki are both quite normal places today. Even places with nuclear accidents, such as Chernobyl and Three Mile, don't look like deserts and don't seem to have deformed life running around.

For the purposes of establishing a specific scenario, let us assume that the 1983 incident was not correctly identified as a glitch, and instead the officers involved proceeded to launch a complete "retaliatory" strike, causing nuclear war to break out worldwide, dragging all major nations into conflict, and igniting WW3.

Assume more or less total destruction of all the involved parties, and most warheads in every arsenal fired in a short span of time - perhaps a month or two.

I'm curious what effects this would have on climate (local/global), and thereby the flora/fauna. What would such a world actually look like?

## closed as too broad by StephenG, Mołot, L.Dutch♦, Frostfyre, SPavelMay 31 '18 at 12:51

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• In 1983, there were approximately 50,000 nuclear devices (source). If you really want all 50,000 to be used in your scenario, the answer is simple: Complete extinction of humans...and many, many other species. – user535733 May 31 '18 at 1:10
• I always assumed the Mad Max movies (except for the first one) are set in a desert wasteland because everywhere more viable on Australia was near population centers, got nuked, and now they're too radioactive to live near. A chance of survival in the formerly empty desert, most of Australia, is a better option than dying of radiation poisoning. – Schwern May 31 '18 at 3:06
• How long after the war? – Schwern May 31 '18 at 3:10
• @Schwern i hadn't really specified a time, because i wasn't really sure what the impacts of such an event would be - even in the short term. I'm not sure if there would be long-tail impacts that would be more novel than immediate-term ones. – Knetic May 31 '18 at 4:30
• Far too broad. "What would Earth be like after a total nuclear conflict ?" is a question that does fill books. – StephenG May 31 '18 at 8:48

I would have rather put this in a comment, as it really isn't a complete answer, but I don't have enough reputation to comment. But based on what I have read, nuclear winter is a myth, nuclear weapons will not mainly be targeted at population centers, and the vast majority of people will survive. Granted, this is based off of modern numbers of nukes and not 1980s, but the event would not be as civilization ending as commonly thought.

• Hi, and welcome to Stack Overflow. Commenting is a privilege, and going around the restriction with a low quality answer is not acceptable. If you can work this into a proper answer, you'll gain reputation and earn the ability to comment. Be sure to work with the Original Poster's scenario, total nuclear war in 1983. – Schwern May 31 '18 at 3:09
• @RichardSmith +1 because you wanted to comment but couldn't, hopefully you get there soon. Its true you wouldn't want to go for population centers just to kill people and you will 100% go for military locations and possibly manufacturing locations (aka weapons or research). But back then with so many missiles available, you would probably shoot them all off after the enemy has fired because you didn't know the consequences. – Shadowzee May 31 '18 at 4:46
• I think this is a good answer and shouldn't be just a comment. It sums up the sources well enough and the links are interesting. – kapex May 31 '18 at 9:29
• Direct damage is popularly overemphasized, but most people who study the problem seriously consider it relatively mild. The indirect damage is the main consideration, and the hardest to predict. It's not a coincidence that most post-nuclear apocalyptic stories are set a long time after the war itself. Even if the war has no ecological effect, just e.g. a disruption of trade, billions can die. The very things that lead to the nuclear war in the first place would be incredibly damaging on their own even if all the nukes fizzled out. – Luaan May 31 '18 at 9:48

You have to remember that Hiroshima and Nagasaki were just two bombs. Little Boy and Fat Boy were 15,000 and 21,000 tons of TNT respectively, and each of those was enough to basically destroy the entire city.

In the 1980's there were appropriately 40,000 nuclear bombs. With approximately 4416 cities in the world (I'm not sure if this is accurate or the definition used to make this number), you could basically bomb every city in the world, then repeat it a couple times for good measure.

The problem is that after this nuclear war, all your infrastructure and most of the population is gone. Hiroshima and Nagasaki were only 2 cities, the rest of Japans industry was still there and they still have the people and man power to produce goods, clean up and rebuild. With a nuclear war this doesn't happen. Key infrastructure and large population zones are the key targets and they will be destroyed or covered with so much radiation they become inhabitable.

So with your main cities all destroyed and in ruins (sort of like fallout cities I would assume or just mostly flat and rubble depending on the size) the only people you really have left are out in the country. They get to live normal-ish lives. The radiation takes some time to spread and it isn't as concentrated because they are fairly far away from the detonation point. But overtime their quality of life will also decrease. Fuel becomes hard to get, you have to find and scavenge for it because no one can produce it anymore. All the factories are gone and all you have left are whats left in tanks or on the shelf products in broken down stores.

You still have vehicles, but they break down over time, and as more time goes on, the spare parts you can take off the shelf are used up. You can only fix it with what spare parts you can fashion using materials you've found. It doesn't matter if you managed to preserve an entire industrial warehouse full of tools and machines. They will decay and you won't be able to replace them because you won't have the knowledge to (The internet and power will 100% go down).

This means that over time, the people in safe communities out in the country will have to slowly migrate towards the city. Spare parts and useful equipment become exceedingly rare but since they are more likely to exist in the city, people will naturally gravitate towards it in the hopes of finding extra resources among the ruins. With the lack of law enforcement some people, looking for food and to secure their own future will become lawless. Places with abundant natural resources are fought over and highly defended, and key resources like clean water become worth fighting to the death over.

I don't know much about Mad Max, but I would say the Fallouts premise isn't entirely false. Your cities will probably be a lot more decayed, guns and bullets will be more rare and never really used and there would probably be a lot more flora considering the 210 years that pass in before fallout 4 takes place.

• There's also the chance of failure to detonate. Some lucky cities may survive relatively intact, and an even luckier few unscathed. And military and nuclear launch sites will be targeted as well. Not all cities have military bases in/near them. – GoingFTL May 31 '18 at 5:33
• @GoingFTL Even then, you would also target key manufacturing areas and ports effectively cutting off production. Any cities that do survive will have a hard time surviving as they are without external supplies, will have an influx of refugees or survivors, lack of funds since your government will probably be gone. City maintenance goes out the window, people might loot and try gather as much supplies as possible and you end up with the Commonwealth in Fallout 4 after a couple hundred years. (I'm assuming MAD occurs not NUTS) – Shadowzee May 31 '18 at 6:00
• @GoingFTL Cities have never in history been self-sufficient. Even in the worst times of the industrial revolution, they relied on massive inputs of resources to sustain their population; today, the reliance is even higher, given that most of the activity has switched away from using coal directly, and instead uses electricity. The distance between the sources of these resources and the cities has been increasing - something that's quite problematic if your infrastructure breaks down. Hitting a city would almost be merciful to most of its inhabitants if the breakdown is bad enough. – Luaan May 31 '18 at 10:00

While the short term consequences of a nuclear war are, to put it mildly, "not good", the long term consequences of wiping out human civilization would be very good for everything else on the planet. From the point of view of most other species on Earth, we are the worst thing to happen to this planet in 65 million years.

Our impact is so profound, geologists have proposed the Anthropocene, an epoch dominated by our effect on the world, climate, atmosphere, and ground itself. Ecologists have proposed that we're undergoing a sixth mass extinction, the Holocene extinction, caused by human activity. Species are disappearing at a rate 100 to 1000 times faster than without us.

While 50,000 nuclear warheads is enough to destroy all of the population centers of the Earth, there's a whole lot of Earth that is sparsely populated and would not be targeted. Many plants and animals are far more resilient to radiation and toxicity than we are and can flourish where we cannot.

Our most toxic sites, like the area around Chernobyl, are wildlife refuges simply because humans don't go there anymore. Despite the extreme pollution, wildlife flourishes because having humans around is worse than a toxic environment. A sort of involuntary park.

A nuclear war will bring an abrupt halt, or greatly diminish, most industrial activity. The cutting down of forests will stop. Fishing and farming will halt. The burning of petroleum and coal will cease. Once the fallout kicked up by the war settles down, the atmosphere will begin to rebound. The skies will clear. The air will be cleaner than it has been in a century.

The extra 40 ppm of $\text{CO}^2$ we've dumped into the atmosphere since the 1980s won't have happened, climate change won't be as far long. Once the one time contribution of carbon from the war, burning cities and forests, has stopped the carbon cycle will begin to correct itself. Calcification of the seas will reverse. Human caused climate change will be averted in the long term.

Rather than being a blasted wasteland, a post-nuclear world might be a paradise for everything else. Flora and fauna might flourish without us. Not because a nuclear war will be good for the world, but because we're so awful to it.

• ‘Having humans around is worse than a toxic environment’ - life can work around toxicity, but it can’t work around anything as volatile as we are. – Joe Bloggs May 31 '18 at 5:46
• A rather depression thought, but I believe you are mostly correct. There are certain species though that thrive due to human habitation, rats, and pigeons for example. – user1751825 May 31 '18 at 7:28
• Forests will no longer be managed, and will start to decay, releasing their captured carbon back into the atmosphere. Petroleum will likely burn even more freely, as the unmaintained oilfields will break and likely burn. Reduced particulates in the atmosphere will temporarily worsen impacts of climate change. Droughts will get worse (for a time), and ecosystems will be destroyed. Humans do a lot of damage, yes. But we also care for our environment, a lot. The impact from humans disappearing would be massive, and just like any such change, it will benefit some to the detriment to others. – Luaan May 31 '18 at 9:54
• @Luaan - Forests do tend to manage themselves, when left alone. And oil fields would rapidly stop leaking; it takes a lot of effort to get oil out of most of our fields, being in advanced states of depletion. Natural oil formation and leakage rates are <1% of human usage, probably <0.01%. – Andrew Dodds May 31 '18 at 10:42
• @Luaan Forests "managed" themselves for hundreds of millions of years before humans started trying to interfere. The only forests that would see any decline after we're gone, are the little ones in our city parks, comprised of species not naturally adapted to the climate in which they're living. – user1751825 May 31 '18 at 23:00

Let's assume that 50,000 nuclear devices are launched. Note that this is itself probably an overestimate; by definition the first targets are the weapons themselves, and anything that suffers a launch delay probably never gets fired at all. Furthermore, there have been few if any actual live tests of ICBMs; this alone means that failure rates will be high. Quite a lot of warheads will be damaged by the stress of launch and reentry and fail to explode, or not explode properly, or miss targets by sufficiently large amounts that they are basically harmless. And because of this, some high-priority targets would be double or triple targeted - and two explosions in the same place don't do as much damage as two separated explosions.

And from this we see something else: much of the megatonnage - perhaps 20 Gt for the US - was concentrated in a small number of warheads. Basically, you have a few hundred 'citybuster' multi-megaton warheads in each stockpile, and thousands of smaller warheads.

Again from here there is the effect of localisation. Some areas of the northern hemisphere would be disproportionately targeted (i.e. The USA, Russia, and Europe, plus possibly China. But southern hemisphere countries like the whole of Latin America, India, Africa and to some extent Australia would be relatively unscathed.

Fallout from nuclear weapons is surprisingly light, especially at distance. This is because by definition, as little Uranium and Plutonium as possible are used; these materials are expensive and heavy. Essentially, if you were in much of the southern hemisphere and not next to a military base owned by the US, you might not notice.

Even in heavily targeted areas, if we assume a 5km average radius of destruction, that's 80km2 per bomb, or 4 million km2 of complete destruction for 50,000k explosions. That's half the land area of the US.

There would be a 'nuclear winter' effect.. but we have already seen this with volcanic eruptions. We would see some global cooling for the 2-3 years it took for the particulates to settle out. For wildlife, this would be no more than the normal effects of a couple of bad seasons.

For the heavily bombarded and radioactive zones, we can compare to the Chernobyl area. After some initial destruction from acute radiation poisoning - generally localized - The removal of humans appears to benefit wildlife far more than increased background radiation harms it. Expect forests to rapidly regrow in the destroyed areas.

So, how does this answer the question? Western civilization as we know it would be devastated; many - perhaps most - people in North America, Europe, Russia and China might die either directly or from famine/disease in the aftermath. After a coupe of years of disruption, wildlife would start to thrive and reclaim the ruins of the cities and suburbs. Human civilization would probably continue in the southern hemisphere, and recolonize the North after a few decades.

It is also quite possible that between failures, counter strikes on weapons and over-concentration on military targets, the destruction would be much less than feared and most countries would still exist in some form.

The immediate problem wouldn't be the radiation or blasts - I wouldn't go near, say, Cheyenne Mountain but for the majority of the planet's surface, that wouldn't be your issue. Your issue would be the enormous quantities of dust and dirt kicked up by the detonations, along with particulate matter from the explosions themselves. Very large volcanic eruptions have been known to cause volcanic winters over large parts of the globe, with cooling, sharply reduced crop yields, and the like. For most eruptions, these effects mostly pass after a year or so (or at least I've not seen reference to one that was multiple years long) but my impression is that nuclear winter can last quite a bit longer, and could easily be a mass-extinction event on its own.

• The amount of megatonnage needed to start a nuclear winter is a planetary biosphere irradiating event in and of itself so there really wouldnt be anybody around to see it. – TCAT117 May 31 '18 at 0:04
• @TCAT117 If you're talking about a nuclear winter that lasts for centuries, sure. But that's not necessary to destroy most of human population - if it's also combined with the usual desolation of war and breakdown in trade, communications etc. In that case, even a few years with bad harvests in a sequence is enough, and that's certainly within our reach without doing significant "direct radioactivity related" damage. – Luaan May 31 '18 at 10:04

I see three effects from nuclear exchange: blast damage, radiation damage and climatic damage. The first two have been looked at by other answers, but I wanted to look at the third.

The climatic damage is hard to quantify. According to wikipedia, in 1985 there were 61 thousand weapons. It is hard to translate this into a equivalent total TNT tonnage (as I can't find any numbers for weapon counts at each yield - they vary from 25kT to 50MT), but if we assume that the average strategic weapon if 1MT, and that 10% of all weapons are strategic (as opposed to theatre/naval weapons, which would be less likely to be deployed/relevant in this scenario), and that half of these are successfully, then we get a total TNT equivalent tonnage of perhaps 3GT, which I consider to be something of a conservative, if highly uncertain, guess.

This is a lot of energy driving dust into the atmosphere. The 1883 eruption of Krakatoa (approx 200MT) caused a global temperature drop of 1degC as well as changes in local weather patterns for five years. If we were to release 15 times as much energy, the effects, one might speculate, could be 15 times worse. I stress that climatic reaction is very unlikely to be linear with detonation energy (i.e., very unlikely temperatures would drop 15degC!); but it does illustrate that the climatic effects could be real, substantial and very problematic for survivors who are already in a bad state. To provide some context, this energy would be less than a thousandth, though, of that of the dinosaur-killing Chicxulub event.

It seems likely (or at least plausible) that the changed global conditions (and its suddenness) would impact the natural foodchains sufficiently that a minor extinction event might occur. Humans, already battered by the sudden loss of infrastructure and industrial base, would have a hard time quickly adapting to the changed conditions but certainly they would manage it in some places. Modern agriculture would be ruined, but subsistence agriculture - which is all that is needed when more than half the world's population are dead - would likely suffice.