EA - Population After a Catastrophe by Stan Pinsent

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Welcome to The Nonlinear Library, where we use Text-to-Speech software to convert the best writing from the Rationalist and EA communities into audio. This is: Population After a Catastrophe, published by Stan Pinsent on October 3, 2023 on The Effective Altruism Forum.This was written in my role as researcher at CEARCH, but any opinions expressed are my own.This report uses population dynamics to explore the effects of a near-existential catastrophe on long-term value.SummaryGlobal population would probably not recover to current levels after a major catastrophe. Low-fertility values would largely endure. If we reindustrialize quickly, population will stabilize far lower.Population "peaking lower" after a catastrophe would make it harder to avoid terminal population decline. Tech solutions would be harder to reach, and there would be less time to find a solution.Post-catastrophe worlds that avoid terminal population decline are likely to emerge with values very different to our own. Population could stabilize because of authoritarian governments, prescriptive gender roles or civil strife, or alternatively from increased collective concern for the future.Conclusion: Near-existential catastrophes are likely to decrease the value of the future through decreased resilience and the lock-in of bad values. Avoiding these catastrophes should rank alongside avoiding existential catastrophes.IntroductionIn this report I use population dynamics to explore the question "What are the long-term existential consequences of a non-existential catastrophe?". I do not claim that population dynamics are the only, or even the most important, consideration.Others have written about the short-term existential effects of a global catastrophe. Luisa Rodriguez argues that even in cases where >90% of the global population is killed, it is unlikely that all viable groups of survivors will fail to make it through the ensuing decades (Rodriguez, 2020). The Global Catastrophic Risk Institute has begun to explore the long-term consequences of catastrophe, although they consider this "rather grim and difficult-to-study topic" to be neglected (GCRI).What comes after the aftermath of a catastrophe is very difficult to predict, as life will be driven by unknown political and cultural forces. However, I argue that many of the familiar features of population dynamics will continue to apply.Even without a catastrophe, we face a possible population problem. As countries develop, their populations peak and begin to decline. If these trends continue, global population will shrink until either we "master" the problem of population, or we can no longer maintain industrialized civilization (multiple working papers, Population Wellbeing Initiative, 2023). It could be argued that this is not a pressing problem. It will be centuries before global population drops below 1 billion, so we have time to overcome demographic decline or to make it irrelevant by relying on artificial people. But in the aftermath of a global catastrophe there may be less time and fewer people available to solve the problem.Longtermists may argue that most future value is in the scenarios where we overcome reproductive constraints and expand to the stars (Siegmann & Mota Freitas, 2022). My findings do not contradict this. But such scenarios appear to be significantly less likely in a post-catastrophe world. And the worlds in which we do bounce back seem likely to have values very different from our own.Population recovery after a catastropheIn this section I examine three models for determining population growth. I find that full population recovery after a major global catastrophe is unlikely, and that the worlds which do recover are likely to emerge with values very different from those of the pre-catastrophe world.It's worth noting that a catastrophe need not inflict its damage at one point in time. The effects of some historical famines and pandemics have unfurled over many yea...