Nuclear war has long represented the ultimate doomsday scenario. But investigative journalist and author Annie Jacobsen says biological warfare may pose an even greater overall threat, in part because the barriers to developing a bioweapon are dramatically lower.

On GZERO World, Jacobsen explains to Ian Bremmer why nuclear weapons require closely guarded materials, enormously expensive delivery systems, and decades of technical expertise, while many of those obstacles don’t exist for biological weapons.

And as artificial intelligence makes sophisticated scientific expertise easier to access, that gap could grow even wider. Jacobsen explains why advances in AI are changing the biological threat landscape – and potentially putting dangerous capabilities within reach of more people.