The chapter explores the potential catastrophic consequences of nuclear winter, delving into advancements in climate modeling revealing severe impacts like landmass freezing and agricultural collapse. It discusses historical events like the Reykjavik summit, the risks of current nuclear treaties due to leaders like Putin and Trump, and a notable incident in 1983 where a man named Petrov prevented a nuclear missile attack. The chapter also touches on recent alarming events linked to Russia threatening to use nuclear weapons in the Ukraine conflict, emphasizing the significant international implications and dangers.