OWEN LEWIS, ALBERTA Asteroids. Solar storms. Supernova. Gamma ray bursts. Space is trying to kill us, and it’s time to take it seriously.

CLAIRE BERLINSKI, PARIS The pace of technological change makes the 21st century more dangerous to our species than any before. Unless we work diligently to mitigate the risks, it will be a century of catastrophes. But when we think about these kinds of risks, we are prone to grave cognitive mishaps.

We have come close to nuclear annihilation many times. We have fixed nothing.