Abstract We look at classifying extinction risks in three different ways, which affect how we can intervene to reduce risk. First, how does it start causing damage? Second, how does it reach the scale of a global catastrophe? Third, how does it reach everyone? In all of these three phases there is a defence layer that blocks most risks: First, we can prevent catastrophes from occurring. Second, we can respond to catastrophes before they reach a global scale. Third, humanity is resilient against extinction even in the face of global catastrophes. The largest probability of extinction is posed when all of these defences are weak, that is, by risks we are unlikely to prevent, unlikely to successfully respond to, and unlikely to be resilient against. We find that it’s usually best to invest significantly into strengthening all three defence layers. We also suggest ways to do so tailored to the classes of risk we identify. Lastly, we discuss the importance of underlying risk factors – events or structural conditions that may weaken the defence layers even without posing a risk of immediate extinction themselves.

中文翻译：

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深度防御人类灭绝：预防、反应、复原力以及它们为何重要

摘要 我们以三种不同的方式对灭绝风险进行分类，这会影响我们如何干预以降低风险。首先，它是如何开始造成损害的？第二，它是如何达到全球灾难的规模的？第三，它是如何到达每个人的？在所有这三个阶段中，都有一个防御层可以阻止大多数风险：首先，我们可以防止灾难的发生。其次，我们可以在灾难达到全球规模之前对其做出反应。第三，即使面临全球性灾难，人类也能抵御灭绝。当所有这些防御措施都很薄弱时，灭绝的可能性最大，也就是说，我们不太可能预防、不太可能成功应对和不太可能抵御风险。我们发现通常最好大力投资以加强所有三个防御层。我们还建议根据我们识别的风险类别量身定制的方法。最后，我们讨论了潜在风险因素的重要性——即使不构成立即灭绝的风险，也可能削弱防御层的事件或结构条件。