Nuclear security

14,900 nukes: All the nations armed with atomic weapons and how many they have

The Bulletin of the Atomic Scientists has advanced its symbolic Doomsday Clock by 30 seconds, suggesting humanity is an alarming 2 minutes and 30 seconds away from the brink of an apocalypse.

It's a dramatic statement, but the clock's annual movement is determined by a board of preeminent global security and scientific experts, including 15 Nobel laureates. And they're deadly serious.

Each shift takes into account major threats to civilization, including climate change. However, it assesses — first and foremost — the threat of nuclear war.

This year the Bulletin is especially concerned with the rise of totalitarian and authoritarian regimes, and North Korea's recent weapons tests. But in an unusual move, it took aim at President Donald Trump's aggressive rhetoric on expanding US weapons programs, including his desire to proliferate atomic weapons — just one of which can wipe out millions of people in a matter of seconds — to other countries.