"Why any one of these incidents hasn’t ended in a mass disaster is “pure luck,” Schlosser says in the film. “And the problem with luck is it eventually runs out.” Think about your laptop or car, he suggests. “Nuclear weapons are machines,” he says. “And every machine ever invented eventually goes wrong.”"

http://thebulletin.org/press-release/doomsday-clock-hands-re...

“Three minutes (to midnight) is too close. Far too close. We, the members of the Science and Security Board of the Bulletin of the Atomic Scientists,want to be clear about our decision not to move the hands of the Doomsday Clock in 2016: That decision is not good news, but an expression of dismay that world leaders continue to fail to focus their efforts and the world's attention on reducing the extreme danger posed by nuclear weapons and climate change. When we call these dangers existential, that is exactly what we mean: They threaten the very existence of civilization and therefore should be the first order of business for leaders who care about their constituents and their countries.”

I have personally started to worry always more about the catastrophic software failures. At least here on HN there are people who react to my comments who typically haven't even heard about the concept of developing with the goal of the fault tolerance https://en.wikipedia.org/wiki/Fault_tolerance advocating instead the beloved "fail early fail often" as the best default even when the topic is actually controlling the rockets(!)

http://thebulletin.org/who-would-destroy-world10253

"An existential catastrophe could only happen once in our history. This raises the stakes immensely, and it means that reacting to existential risks won’t work. Humanity must anticipate such risks to avoid them."