Mass-casualty terrorism and terrorism involving unconventional weapons have received extensive academic and policy attention, yet few academics have considered the broader question of whether such behaviours could pose a plausible risk to humanity’s survival or continued flourishing. Despite several terrorist and other violent non-state actors having evinced an interest in causing existential harm to humanity, their ambition has historically vastly outweighed their capability. Nonetheless, three pathways to existential harm exist: existential attack, existential spoilers and systemic harm. Each pathway varies in its risk dynamics considerably. Although an existential attack is plausible, it would require extraordinary levels of terrorist capability. Conversely, modest terrorist capabilities might be sufficient to spoil risk mitigation measures or cause systemic harm, but such actions would only result in existential harm under highly contingent circumstances. Overall, we conclude that the likelihood of terrorism causing existential harm is extremely low, at least in the near to medium term, but it is theoretically possible for terrorists to intentionally destroy humanity.

造成大规模伤亡的恐怖主义和涉及非常规武器的恐怖主义受到了学术界和政策界的广泛关注，但很少有学者考虑过更广泛的问题，即此类行为是否会对人类的生存或持续繁荣构成合理的风险。尽管一些恐怖分子和其他暴力非国家行为者表现出对人类造成生存伤害的兴趣，但他们的野心在历史上远远超过了他们的能力。尽管如此，存在三种存在性伤害的途径：存在性攻击、存在性破坏和系统性伤害。每条途径的风险动态差异很大。尽管存在主义袭击是可能的，但这需要非凡的恐怖分子能力。相反，适度的恐怖分子能力可能足以破坏风险缓解措施或造成系统性损害，但此类行动只会在高度偶然的情况下造成生存损害。总体而言，我们的结论是，至少在中短期内，恐怖主义造成生存伤害的可能性极低，但从理论上讲，恐怖分子有可能故意毁灭人类。