In January this year the Chicago-based Bulletin of the Atomic Scientists, creators of the Doomsday Clock, assessed the world to be 30 seconds closer to annihilation due to threats posed by climate change and nuclear weapons, as well as strident nationalism, fake news, and an intemperate Donald Trump. Chair of the Bulletin’s science and security board, theoretical physicist and author of The Greatest Story Ever Told – So Far Lawrence Krauss returns to the Festival to talk climate change and offer advice on how to stay the apocalypse.