We're closer to nuclear catastrophe than at any point since the Cold War. That's the warning from theoretical physicist Carlo Rovelli.

Drawing on his new book “85 Seconds to Midnight”, Rovelli argues that fear, not strength, is driving a dangerous new global arms race. He explains why he believes humanity has forgotten the lessons of Hiroshima, why today's rearmament risks repeating the mistakes of history, and how artificial intelligence could make the threat of nuclear war even greater.

In this episode of Ways to Change the World, Krishnan Guru-Murthy speaks to theoretical physicist and bestselling author Carlo Rovelli about nuclear weapons, the morality of science, AI, international cooperation and why he believes humanity's greatest enemy is its own irrationality.