For the curious, here is the most recent press release by the Bulletin of Atomic Scientists explaining in detail why they have set the Doomsday Clock to 90 seconds from midnight:
The furthest it went was "17 minutes to midnight" in 1991. What state would the world need to be in to get to "1 hour to midnight"?
During the Cuban Missile Crisis it was set at 7 minutes to midnight. What happened in 2007 and the last 16 years to make the world closer to doom than it was during those 13 days?
It's such a meaningless scale I've never paid attention.
I mean, it's condensing the unknowable event horizon of entire world of geopolitics into one number, so some loss of nuance is to be expected. It's a narrative device, not a scientific instrument.
Re:1991, the fact that nuclear weapons were safely handled during dissolution of the Soviet Union was a huge deal. To get more than 7 minutes of benefit though, those weapons would have to have gone away rather than just be relabeled as Russian. The current state of Ukraine is proof of why it was correct to view this event as cold comfort - simply buying time. 7 minutes worth.
In 2007 climate change was added as a factor to the clock's position. At that time North Korea was actively testing nuclear missiles and Iran's program was gearing up.
Between then and now, nothing substantial has been done on climate change, and nothing substantial has been done to stop North Korea or Iran's nuclear ambitions. The US and Russia have stepped away from open skies treaty and others. Many other geopolitical issues have boiled over.
It's subjective of course but IMO to be an hour from doomsday - we'd need to reverse (not just stop) human accelerated climate change, have much more aggressive nuclear treaties, no large violent geopolitical conflicts, no pending Taiwan invasion, etc.
Even Star Trek's future society is an hour from doomsday, or there'd be nothing for the TV shows.
To read into the justifications for why the clock has been where it is, the Wikipedia article is quite detailed (particularly the 'timeline' section) and has citations to the Bulletin's various communications on the topic, which are nothing if not verbose:
https://thebulletin.org/2023/01/press-release-doomsday-clock...