If you feel a little different today, perhaps it's because humanity is a little closer to its doom.

The symbolic Doomsday Clock was moved two minutes closer to midnight -- the end -- by its timekeepers at the Bulletin of Atomic Scientists.

It's meant to measure how close we are to a global disaster brought on by nuclear war and other man-made threats.

Sivan Kartha serves on the Bulletin's science and security board, and he explains why they've nudged the minute hand closer to midnight: climate change.