Episode Details

Our mission is to protect humanity against biological catastrophes, including those that could lead to human extinction or cause similarly bad outcomes. This series of posts outlines how I think about these most extreme types of risks. My goal here is to share my worldview in a straightforward and compressed form rather than trying to persuade a skeptical audience, although I do share some of my reasoning.

Part I describes my views on the sources of risk and what that implies for how to prioritize response to a biological catastrophe. Part II, describes sources of risk and what that implies for prevention efforts.

TLDR: We can solve the vast majority of existential biological risk by ubiquitously deploying simple and cheap countermeasures like PPE, air filters, UVC, etc. My takes are:

• >99% of existential risk is from engineered threats, <1% natural threats
• >95% of existential risk is targeting humans, <5% targeting agriculture or the environment
• The space of possible human-targeted attacks is basically infinite, so predicting cures or vaccines in advance is hopeless…
• …but the space of physical pathways into a human body is both finite and small, which means, if this is true…
• …we [...]

---

Outline:

(02:13) Direct vs. indirect existential risk

(03:26) Natural vs. engineered

(04:36) Targeting human bodies vs. agriculture vs environment

(08:09) The space of human-targeted biological threats is vast and unpredictable

(10:15) Can we affordably block ~all human-targeted biological risk? (and thus ~all catastrophic bio risk?)

(13:47) A surprisingly hopeful conclusion

The original text contained 12 footnotes which were omitted from this narration.

---

First published:
May 16th, 2026

Source:
https://forum.effectivealtruism.org/posts/2j9xh7CmFjWktCWhR/how-i-think-about-catastrophic-biological-risk-part-i

Linkpost URL:
https://defensesindepth.bio/how-i-think-about-catastrophic-biological-risk-part-i/

---

Narrated by TYPE III AUDIO.