The difference between existential risks and global catastrophic risks

A global catastrophic risk is a possible future event that would cause severe harm to humans on a global scale.¹ An existential risk is a global catastrophic risk that has a chance of rendering humanity extinct.²

One example of a global catastrophic risk is the prospect of nuclear war. Such an event can be a danger to all of humanity, not just those killed directly. The destruction of many cities could destabilize the global economy and might also cause nuclear winter.

Nuclear war is also an existential risk. It has been estimated that the detonation of more than 50 nuclear warheads could set off a nuclear winter.³ Thousands of warheads exist today. The detonation of a significant number of them can cause the extinction of humanity.

These categories overlap. Many possible future events that qualify as global catastrophic risks would also have a chance of causing human extinction if they were particularly severe. In fact, many of the discussions, ideas, and knowledge gathered in the study of one of these types of risk can easily be applied to the other.

To close, it’s worth highlighting a few crucial facts that apply to both of these areas of study:

• Catastrophes can be caused by nature or by humans
• Anthropogenic (or human-caused) risks are now estimated to be much more dangerous than natural risks
• It takes great care and diligence to think clearly about risks like these
• More attention needs to be paid to these challenges; the stakes are too high for us to take these risks lightly

1. Wikipedia: Global Catastrophic Risk. [↩]
2. Bostrom, N. (2013). Existential risk prevention as global priority. Global Policy, 4(1), 15-31. [↩]
3. Baum, S. D. (2015). Winter-safe deterrence: The risk of nuclear winter and its challenge to deterrence. Contemporary Security Policy, 36(1), 123-148. [↩]