Prepare for Nuclear Winter

If a 1km asteroid were to hit the Earth, the dust it kicked up would block most sunlight over most of the world for 3 to 10 years. There’s only a one in a million chance of that happening per year, however. Whew. However, there’s a ten times bigger chance that a super volcano, such as the one hiding under Yellowstone, might explode, for a similar result. And I’d put the chance of a full scale nuclear war at ten to one hundred times larger than that: one in ten thousand to one thousand per year. Over a century, that becomes a one to ten percent chance. Not whew; grimace instead.

There is a substantial chance that a full scale nuclear war would produce a nuclear winter, with a similar effect: sunlight is blocked for 3-10 years or more. Yes, there are good criticisms of the more extreme forecasts, but there’s still a big chance the sun gets blocked in a full scale nuclear war, and there’s even a substantial chance of the same result in a mere regional war, where only 100 nukes explode (the world now has 15,000 nukes).

I’ll summarize this as saying we face roughly a one in 10,000 chance per year of most all sunlight on Earth being blocked for 5 to 10 years. Which accumulates to become a 1% chance per century. This is about as big as your one in 9000 personal chance each year of dying in a car accident, or your one in 7500 chance of dying from poisoining. We treat both of these other risks as nontrivial, and put substantial efforts into reducing and mitigating such risks, as we also do for many much smaller risks, such as dying from guns, fire, drowning, or plane crashes. So this risk of losing sunlight for 5-10 years seems well worth reducing or mitigating, if possible.

Even in the best case, the world has only enough stored food to feed everyone for about a year. If the population then gradually declined due to cannibalism of the living, the population falls in half every month, and we’d all be dead in a few years. To save your family by storing ten years of food, you not only have to spend a huge sum now, you’d have to stay very well hidden or defended. Just not gonna happen.

Yeah, probably a few people live on, and so humanity doesn’t go extinct. But the only realistic chance most of us have of surviving in this scenario is to use our vast industrial and scientific abilities to make food. We actually know of many plausible ways to make more than enough food to feed everyone for ten years, even with no sunlight. And even if big chunks of the world economy are in shambles. But for that to work, we must preserve enough social order to make use of at least the core of key social institutions.

Many people presume that as soon as everyone hears about a big problem like this, all social institutions immediately collapse and everyone retreats to their compound to fight a war of all against all, perhaps organized via local Mad-Max-style warlords. But in places where this happens, everyone dies, or moves to places where something else happens.

Many take this as an opportunity to renew their favorite debate, on the right roles for government in society. But while there are clearly many strong roles for government to play in such a situation, it seems unlikely that government can smoothly step into all of the roles required here. Instead, we need an effective industry, to make food, collect its inputs, allocate its workers, and distribute its products. And we need to prepare enough to allow a smooth transition in a crisis; waiting until after the sunlights goes to try to plan this probably ends badly.

Thus while there are important technical aspects of this problem, the core of the problem is social: how to preserve functioning social institutions in a crisis. So I call to social scientist superheroes: we light the “bat signal”, and call on you to apply your superpowers. How can we keep enough peace to make enough food, so we don’t all starve, if Earth loses sunlight for a decade?

To learn more on making food without sunlight, see ALLFED.

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  • arch1

    Those people would be super heroes indeed – solving world hunger in the midst of such a mega-crisis is a tall order. One of the few things going for them in such a scenario would be that only true adherents of apocalyptic religions could deny the problem.

    Speaking of which, it may be an even taller order but I wonder whether there is more bang for the social science buck in trying to mitigate the root causes of this and other global threats (including biowar): irrationality, sectarianism, under-valuing of human cooperation.

    Back to nuclear winter: I don’t want to hijack the social science angle but suggest that alternative approaches may also be worth pursuing (e.g. self-reproducing automata which use stratospheric solar energy to radically enhance soot dry deposition rate, perhaps even manufacturing food in the process; though I don’t know whether this is actually possible).

    • Lliamander

      > wonder whether there is more bang for the social science buck in trying to mitigate the root causes of this and other global threats (including biowar): irrationality, sectarianism, under-valuing of human cooperation.

      Now, when I read that what I hear is “mind control”. I don’t feel that I can understate the risks such a solution would have.

      At the end of the day, I don’t feel like there is a better solution to increasing cooperation than through non-violent communication. People are different from each other. These differences can lead to conflict but I suspect serve a valuable purpose. Respect their needs, their self image, and their freedom to reject your proposal. Earn their trust.

      > I don’t want to hijack the social science angle but suggest that alternative approaches may also be worth pursuing (e.g. self-reproducing automata which use stratospheric solar energy to radically enhance soot dry deposition rate, perhaps even manufacturing food in the process; though I don’t know whether this is actually possible).

      Oh, are you suggesting essentially a “sky sweeper” to cleanup the ash/soot/dirt/whatever blocking sunlight? Interesting! Not only does this approach avoid much political strife, it’s something we can actually *test* (by deploying it on active volcanoes, etc.).

      • arch1

        Re: “…mitigat[ing] root causes…” I was not intending to advocate mind control or violence. But in a world where individuals or small groups will soon have the capacity to destroy a city, region, or even the majority of humanity (bio warfare) based on their ideas, it seems pretty clear for example that we should seek universal disavowal of the notion that *any* ideas should be exempt from rational discussion, scrutiny and even intense criticism.
        Re: ‘sky sweeper’ – I don’t know whether or how the self-reproducing automaton would work, but yes the idea is that it would do a massive soot cleanup. (I’m sure this isn’t original; also it seems possible this approach might have some synergy with some approaches to active AGW mitigation)

      • Lliamander

        > I was not intending to advocate mind control or violence.

        Forgive me, I think I was unclear. I did mean to accuse of of advocating those things.

        With regard to mind control, I was more meaning that while we can lament the difficulty in making people see reason, if scientists did ever come up with a convenient way to change peoples’ minds I think we’d be doomed.

        With regard to violence, I was referring to a specific communication technique called “non violent communication” (NVC). It’s one thing to ask people think about and work towards the common good; it’s another for them to actually buy into it. I think many people are rightly distrustful of “common good” claims, specifically because too often individuals can get trampled in pursuit of the “common good”. NVC is a tool to for connecting the individual to the common good (or perhaps, collaboratively defining the common good). The trick is that you have to be open to the other party not reacting in the way you wanted them to.

        > it seems pretty clear for example that we should seek universal disavowal of the notion that *any* ideas should be exempt from rational discussion, scrutiny and even intense criticism.

        Indeed. But there a few challenges to such open discussion:

        – When ever criticizing an idea, you must always have another idea that servers as an axiom against which we test that idea. Which axioms should we use, and how do we test those axioms themselves?

        – How do we navigate around the issue that all people tend to attach certain beliefs/ideas to their self-concept (and hence become defensive)? I think NVC can be useful here

        – How do we navigate the space of ideas to identify which ones are useful to criticize?

        > also it seems possible this approach might have some synergy with some approaches to active AGW mitigation

        Indeed, that would be a nice bonus.

      • arch1

        Thanks Lliamander. I will look into NVC. Re: your axioms question, I like Sam Harris’s perspective that the only thing that really matters is the well-being of conscious creatures (thus also things that directly or indirectly serve that end).

      • we should seek universal disavowal of the notion that *any* ideas should be exempt from rational discussion, scrutiny and even intense criticism.

        To be pedantic: Is the view that no ideas should be immune to critical scrutiny apply to this idea? Is that consistent with universal disoval?

      • lump1

        Yes. I would expect such an idea to survive critical scrutiny – and if it doesn’t, we should be happy to see it go. This leads to no self-reference paradox.

      • Why would you set your sights on universal disavowal of an idea if you want to subject it to continuing critical scrutiny? Not a self-reference paradox but a pragmatically self-defeating goal.

      • arch1

        Yes to the first question. To the second, I am advocating (however clumsily) that we regard no idea as unassailable, and that we try to convince others of this too. ‘Universal disavowal’ was a bad choice of words because the only way to achieve that would indeed involve massive coercion. Like any idea, it is possible that new information/changed conditions/critical scrutiny will reveal the need to modify or eliminate it. But for now, it’s simple: No privileged ideas.

  • Silent Cal

    Can you elaborate on which roles you don’t think the government can fill, and why?

    For instance, does security have to be an integral part of the industry we’re designing, or can we assume the government will take care of that?

  • lump1

    If this sort of disaster rationale helps advance the research, I’m all for it. For me, though, there more interesting applications for food made without sunlight. I’m much more excited about colonies in space, where we will almost certainly not be growing fields of grain under glass domes (b/c radiation, micrometeorites, leaks, low density, etc.). Sunless food-generating capacity would make human civilization far more portable.

    The sooner we get good at making food this way, the sooner we can use that food to supplement our diets even in happy times. This could allow the population to keep growing while we reduce our footprint on the planet’s surface, maybe even re-wilding some marginal agricultural land.

    • David Denkenberger

      Two options in space are solar and nuclear powered direct chemical synthesis of food from the CO2 we breathe out. There are also electrically powered bacteria. Incidentally, these could also be useful for refuges to repopulate the earth (space-based or terrestrial): .

  • Travis Rivera

    Would likely use a nuclear/fossil fuel/wind/water power plant and LEDs in an enclosed indoor environment with pumped water to deliver nutrients generated by fish not unlike some aquaponics factories.

  • Dave Lindbergh

    In movies, after something like you describe the social fabric always falls apart and society becomes a ‘Mad Max’ dystopia of isolated individuals and tribes.

    I can’t think of a single historical incident when anything like that happened. After devastating wars, epidemic, famine, or siege people pull together and become more cooperative.

    I don’t think everything will fall apart. We’ll still have industry and government and hierarchy (maybe more so than in ordinary times).

    But, yes, some emergency preparedness is definitely called for.

  • Brian Slesinsky

    It’s not just food. We are currently increasing our dependency on sunlight through the growth of solar power. To some extent, wind energy depends on sunlight to heat the earth unevenly. And of course temperatures would go down dramatically, which implies much more need for warm buildings and heating.

    Polar regions are somewhat more prepared to start with, since they live indoors most of the time and in the dark for part of the year. But Antarctica imports almost everything at great expense; figuring out how to cut down on food imports might be a good way to explore feasible alternatives to agriculture.

    It seems odd to me that there is so much attention paid to someday living on Mars and relatively little paid to sustainable living in relatively inhospitable areas on Earth, which would be much easier and yet are still quite a challenge.

  • And I’d put the chance of a full scale nuclear war at ten to one hundred times larger than that: one in ten thousand to one thousand per year.

    Is this based on anything? [I’ve grown somewhat disgusted with “Bayesians” who think they’re being scientific because they (essentially arbitrarily) “quantify” their priors.]

    • David Denkenberger

      See my comment above.

  • Doug

    I propose a novel solution: use crypto-based secret sharing to deter defection. Hide the location of critical supplies in random locations around a region. Store the location using some secret sharing scheme based on asymmetric encryption. Distribute the private keys across all the residents of the region (or some large random sub-sample). The higher percentage of key holders that work together, the more supply locations will be revealed.

    War-lord-ism works when a small coalition of skilled soldiers can dominate the resources in a region. Under this proposal, inclusive cooperative coalitions have a strong intrinsic advantage. Since everyone holds some piece of the secret key, strong and weak alike, it helps put women, children, and the frail back on more of an equal footing with combat-ready young men.

    Finally I’d say, place orbital satellites that broadcast new crypto keys every month. Keep 10 years of supply hidden, with the caveat that certain supplies will only become available at a certain time in the future. The secret sharing scheme will only unlock next month’s supplies with the specific monthly key. If the inclusive coalition immediately recovers all the supplies it’s vulnerable to being overrun.

  • Robert Koslover

    OK, I know this question will anger some people, but are “social scientists” actually the right people for this job? Have they previously led the way in saving humanity from great world crises? I mean, I suppose you could make a partial case if you consider great western philosophers and great leaders/politicians like (as just one example) Winston Churchill to have been “social scientists.” One could include a subset of economists perhaps, those whose work helped influence/defend and encourage free markets that drive our wealth and technology. Hmm. Should we consider lawyers, politicians, soldiers/sailors, businessmen, and farmers to all be subsets of “social scientists?” (We could include many of America’s founding fathers then, so I’d likely be in favor of that.) Would anyone care to offer examples of modern-style “social scientists” who have clearly played major roles in advancing human health and welfare? Have social scientists brought life to deserts? Have social scientists thwarted epidemics? I presume some have contributed, but are they the leading contributors? Should epidemiology be considered a social science? Have social scientists provided clean drinking water and/or advanced/more-efficient agriculture to billions? Should civil engineering and farming be considered social sciences? Is highway planning a social science — or is it a field of engineering and/or politics? Dare I suggest, perhaps one should first be asking engineers, farmers, businessmen, and (gasp) even politicians for guidance in this important matter?

    • I wasn’t trying to pick a fight and favor some groups over others. I was just calling for people to solve a problem in social organization.

      • Robert Koslover

        But is addressing a potential nuclear winter primarily a “social organization” problem? Interestingly, the folks at the link you provided (to AllFed) do not seem to be identified as social scientists, per se.

      • The ALLFED folks are mainly engineers who are doing their part of what needs doing. But their efforts aren’t enough; we also need enough social support for the engineers now and in a crisis.

    • Curt Adams

      Social science is pretty new. How often can any group take sole credit for a major improvement? I suspect that social science played at least an important role in a number of improvements in the twentieth century like the reductions in war for conquest and civil rights.

  • Nicholas Kreston

    “How can we keep enough peace to make enough food … for a decade?”

    I think this is a good question, but in many ways I think that peace should be thought of more as an epiphenomenon of the answer to two other good questions. One, from where do you get water? And two, how do you produce the food?

    There are a host of important subsidiary questions to these as well. For instance, is it safe for you to go outside? Would you want to? Do I have to travel for water or do I have a reliable and sustainable clean source?

    The answers to those questions set up the environmental conditions that our post-sunlight survival must contend with. They determine if we are a nomadic, semi-permanent, or permanent society. Each of those types of societies have different needs and divisions of labor associated with their security (hence, “keep enough peace”) requirements. If everyone is walking in tribes dragging their food machines around with them looking for water, then the method for keeping the peace will look like however nomadic societies do that. I’m not an anthropologist, so I don’t know.

    But we still have the issue of how we produce the food. Let’s assume that there aren’t any more global food supply chains and that instead machines make food. If machines make the food, how large are they? On the scale of combustion engine, microwave, or toaster? Or, larger, like an aircraft carrier? What level of skill is necessary to build and fix them? Do these machines require periodic investment to maintain? Who owns them?

    The person or people who own the machines are going to be the ones with a strong material interest in protecting them. Those people are going to have a big enough voice in this society that however they need to protect these machines, that’s the strategy that will be adopted to keep the peace. In other words, the machine owners aren’t going to let a given leader stick around long if she or he can’t secure that society’s most important machines ever.

    If corporate entities own these machines because it is a capital intensive operation that they use to sell food commodities in open markets, then it requires a property rights regime and professional security forces. If these machines are small and light enough that you can haul them around with your tribe while looking for fresh water, then you probably don’t need anything too elaborate, just some armed fellows and some protocols for dealing with non-affiliates.

    Either way, the two issues that are going to determine how you “keep enough peace” are water availability and the division of labor required to produce the food. It goes without saying that a nomadic small-machine society and a permanent big-machine society have very different needs. (That is not to say there aren’t more options than those two, but the same principle applies.)

  • model_1066

    I question the entire ‘nuclear winter’ premise. All the nukes going off at once will occur above ground if used for war, and there simply isn’t nearly enough energy to equal even a minor volcanic eruption. Nukes vaporize shit, and undoubtedly start secondary fires, but their ejectementa is not even close to the scale of the cubic miles of volcanic spew ejected upwards into the atmosphere from even a moderate eruption. So the idea of sunlight being blocked out for years by a nuke war is a fantasy.

  • And I’d put the chance of a full scale nuclear war at ten to one hundred times larger than that: one in ten thousand to one thousand per year. Over a century, that becomes a one to ten percent chance.

    I don’t think a plausible model of the likelihood of nuclear war assumes the outcomes for years are independent. Each year that we survived the Cold War period increased the credibility of Mutually Assured Destruction and decreased the probability of war for following years.

    I bring this up because your entire argument (that the risk of nuclear winter is worth preparing for) rests on an apparently arbitrary likelihood estimate combined with an impluasible assumption.

    [In making this criticism, I assume it makes sense to assign probabilities to one-off events (at least under one-off descriptions). I don’t believe it does. For why I’m interested in this, see “Epistemological implications of a reduction of theoretical implausibility to cognitive dissonance” – ]

    • Curt Adams

      Agreed that the numbers are wild guesses but I don’t think the risks are trivial. There were several close calls in the ’80s when early warning systems malfunctioned. Add in potentially desperate leaders (North Korea if something goes wrong), demented major power leaders, and the potential return of major power rivalries, and I don’t think one in a thousand is implausibly high. With the three early warning failures, if each had a 1 in 50 chance of causing an exchange we’re already there.

      The point is that the risk is high enough over even a normal human lifespan to at least consider mitigation strategies. I think the analogy to asteroid strikes is good – the fairly wobbly estimates of strike probabilities justified a sky survey. That’s mostly done, and has indicated we weren’t going to get hit in the next 1000 years, but I’m still glad we did it.

  • Ari Timonen

    Yes there is a book called “Feeding everyone no matter what”, and I don’t think solving the food supply problem is even hard if we just got the global (and local) coordination to do it. I don’t think it would be even much of the GDP.

    What was interesting is that ROI and expected lives saved per $ was much higher than saving people in Africa in the guy’s presentation (ask Kaj Sotala for link).

  • Ari Timonen

    Also energy supply. Nuclear is much better than sunlight! Even if sunlight would be cheaper. Even if you got food and peace, you still need energy. At least it would be contribute to lack of immigration waves from colder climates and peace.

    Also have they discussed this at UN?

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  • Brian Slesinsky

    I ran across an interesting article [1] that reminded me of this topic. A few quotes from it.

    “Never has the world produced so much more food than can be consumed in one season. World ending stocks of total grains – the leftover supplies before a new harvest – have climbed for four straight years and are poised to reach a record 638 million tonnes in 2016/17, according to USDA data.


    “China’s stockpiling policies, enacted in 2007 when corn supplies were tight, also stimulated oversupply. Aiming for self-sufficiency in grains, Beijing bought virtually the entire domestic crop each year and paid farmers as much as 60 percent more than global prices.

    “The program stuffed Chinese warehouses with some 250 million tonnes of corn by the time Beijing scrapped it last year. China is now boosting incentives for farmers to switch to soybeans from corn.

    “The world’s corn is mainly in China,” said Li Qiang, chief consultant at Shanghai JC Intelligence Co Ltd.

    “He said it will take three to four years for stocks to reach a “normal” level of around 40-50 million tonnes.

    So, I guess the capacity is there to grow and store large amounts of grain, but the question for people worried about nuclear winter or similar disasters is how to convince governments that storing this amount of grain and expanding storage (rather than cutting it back as wasteful excess) is something they should keep doing, on purpose?


    • David Denkenberger

      If it were free, more food storage would make us more resilient to catastrophes. The problem is that to store up five years of food for 7 billion people would cost tens of trillions of dollars (not to mention the fact that it would not protect us if the catastrophe hit soon, and storing fast would cause many more people to starve in the near term). What I am talking about is spending tens of millions of dollars for planning, targeted research and development, so that we are ready to quickly scale up alternate foods.