global catastrophic risk

The risk of an event severe enough to harm people across the whole world, such as the death of a significant fraction of the world's population or the collapse of critical global systems. Thresholds vary, from 10 million deaths or 10 trillion dollars in damage, as proposed by Nick Bostrom and Milan Ćirković, to the loss of a tenth of the world's population. Global catastrophic risks include all existential risksexistential risk, n.: A danger that could end humanity, or shut it out of a good future forever. Some experts count advanced AI among the largest such risks; others think this worry is overblown. but are broader: a catastrophe from which humanity eventually recovers is global-catastrophic but not existential. AI governance has adopted related categories of catastrophic or severe risk with much lower thresholds; California's SB 53SB 53, prop. n.: A 2025 California law requiring developers of the most powerful AI models to publish their safety plans, report serious safety incidents to the state and protect employees who raise alarms., for instance, ties catastrophic risk to incidents causing more than 50 deaths or serious injuries or over a billion dollars in damage, through pathways such as weapons of mass destructionCBRN risk, n.: The danger that AI could help someone make or use chemical, biological, radiological or nuclear weapons — for example, by explaining hard technical steps an attacker could not work out alone., cyberattacks and loss of controlloss of control, n.: A situation in which people can no longer oversee, correct or switch off an AI system, and have no reliable way of getting that power back..

Engineered pandemics rank high on most global catastrophic risk lists, and AI could make them easier to create.