"The whole end-of-the-world idea, which was so important during the hay day of the Doomsday Clock, has kind of retreated back into the realm of religious apocalypses," he said.
Younger generations, those not politically conscious until the 1990s, see it as the stuff of old movies, he said, and can't relate to the feeling that "at any moment, literally any moment, we might be gone."
Though immediate threats to civilization may not be at the top of most people's minds, he said that the clock helps bring a sense of urgency to the threats now facing humanity.
For example, he said, the destruction wrought by climate change will happen gradually, not overnight, but every minute that passes puts us further behind.
"It's an attempt to make us realize that although the threat may be distant the need to do something about is now," he said."