Though the matrix of threats has shifted since the clock's inception, security experts say it still maintains its significance.
"I think that the context has dramatically changed since the end of the Cold War. Everyone lived in a certain level of apprehension. ... The nuclear confrontation was salient and palpable," said Bruce Blair, president of the Washington, D.C.-based think tank World Security Institute. "The clock was a shorthand summary of where we stood."
The prospect of nuclear war with Russia is no longer front and center, he said, but other threats have emerged and deserve attention.
Nuclear stalemates with North Korea and Iran and the recent failure to secure an international accord at the climate conference in Copenhagen are three of the greatest threats facing the world right now, he said.
Spencer Weart, a science historian and former director of the Center for History of Physics at the American Institute of Physics in College Park, Md., said that at this point the clock, in some ways, serves as a reminder of how times have changed.
"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."