This just in: we are just three minutes from midnight. That puts us right where we were last January with respect to the end of civilization as we know it. This is according to the Bulletin of the Atomic Scientists, a magazine you almost certainly do not read. The Bulletin does not appear on any newsstand I’ve ever seen. Most people never give it a moment’s thought. Its Doomsday Clock, however, is another matter. Every time the Clock’s minute hand moves, either inching toward doom or backing away from it, the tick triggers headlines around the world.

And no wonder. Doomsday is a deliciously scary concept, and the idea that we can predict its arrival is kind of unsettling. After all, nobody except Dr. Evil and the latest Bond villain wants to see us “[destroy] our civilization with dangerous technologies of our own making,” as the Bulletin defines the term. Last January, the Clock ticked from five down to three minutes to midnight. It's still there. This can’t be good.

But how bad is it, actually? Whenever Doomsday Clock time rolls around, I roll my eyes, because the Clock doesn’t actually gauge anything measurable. In the real world, clocks keep track of time, but this one certainly does not. The various threats the Clock concerns itself with—nuclear war and climate change are the biggies—have completely different timescales. If Vladimir Putin got up on the wrong side of the bed tomorrow, we could in principle have a devastating nuclear war within a few hours. Even in the worst-case scenario, by contrast, it will take a century or more for climate change to melt the Greenland ice sheet and drive sea level up by 20 feet. So you could say that “one minute” represents anything from a day to a hundred years. Its more truthiness than truth. 

What the clock really measures is worry—that is, how worried members of the Bulletin’s Science and Security Board are about the state of the world. Every year, the board’s dozen or so physicists, climate scientists and policy experts get together to figure out whether the clock will tick, and if so, in what direction and how far. I asked John Mecklin, the Bulletin’s editor, how they go about this. He wouldn’t tell me. “We don’t reveal the exact specifics,” he said, “just because that’s the policy.”

What he is willing to say is that it is not just some people in a room sitting around saying “Hey, how worried are you? I’m really worried. I’m like, a whole minute more worried than I was last year." "Yeah, not me. I'm still in a three-minute state of mind.” 

On the other hand, said Mecklin, “It’s not a numerical answer we got by running some sort of equation or anything. It's the best judgment of really top experts who really know these situations at a granular level.” These experts talk amongst themselves, but they also check in with other experts, including the Bulletin’s Board of Sponsors. This includes no fewer than 16 Nobel laureates, although many of these have no relevant expertise whatever (nevertheless, they’re very smart)

The ups and downs of Doomsday, Russian version. Credit: Wikimedia Commons

I asked Mecklin about that “destroy civilization” thing. Is that perhaps a tad hyperbolic? Not at all, he said. There is good reason to believe a massive thermonuclear war would throw enough debris into the atmosphere to throw the planet into a cold, dark nuclear winter. Deprived of sunlight, plants could die en masse, yanking out the bottom of the food chain and pretty much starving us all. “Some studies have suggested that no more than 50 or 100 bombs would be enough, and there are thousands in stockpiles around the world," Mecklin said. "The idea that a thermonuclear war of any size is not a direct threat to civilization is just wrong.”

So, did the Science and Security Board decide that we're as close as we ever were all-out nuclear war? You might think the Iran nuclear deal would have moved us away from the brink, not toward it, and North Korean dictator Kim Jong-un’s tiny faux H-bomb test earlier this month can’t have changed the equation in any serious way. But we haven't reduced the numbers of nukes lately, and current stockpiles are now being modernized. It’s true that if nuclear weapons didn’t exist at all, or if we let them fall into disrepair, there would be no threat. Since we have no clue about the circumstances under which they would be used, however, and on what scale, it’s hard for me to believe we’re in measurably more danger today than we were, say at the height of the Cold War—when, if you check your history, there wasn’t a single nuclear exchange, let alone a war.

As for climate change, the COP21 talks in Paris last month were widely seen as a major step toward curbing the dangers of greenhouse-gas emissions. Paris was mostly about promises, however, and the Clock people are taking a wait-and-see attitude. So things are still bad. Is civilization on the brink of disaster? Even on our present course, Mecklin said, there’s admittedly a fair amount of uncertainty about exactly what’s going to happen, and how fast. “But if you take a moderately worst case view,” he said, “we run the risk of famines, droughts, mass migrations of climate refugees.” It’s no exaggeration at all, he says, to suggest that civilization would be drastically affected. This isn’t quite the same as being destroyed, but point taken.

Still, I can’t entirely get over the faux precision the whole clock metaphor implies. Because as I mentioned earlier, it doesn’t actually measure anything. When the Clock was first created, the minute hand was set at seven minutes to midnight. The choice of that number was not even remotely scientific. According to the artist Martyl Langsdorf, who created it in 1947, the reason was that “it looked good to my eye.” I kid you not—it says so right on the Clock FAQ page.

Not only was the decision not based in science, but it also put future Clockers in a corner. We can move the hand a long way backward, but with only three minutes left, there is little room to move it very far forward if things get worse, as they obviously can. If the clock moves to two minutes next year, or one minute what happens next? Will they have to start inching forward in seconds? If so, they'll need to redesign the whole thing. 

In any case, you can be forgiven for assuming, wrongly, that the Doomsday Clock is anything more than an excuse for concerned scientists to remind us about the dangerous technology we've created. John Mecklin himself forgives you. “I understand the tendency to make this into some kind of metric, an actual calculation,” he told me.

Which I appreciate, since the way the Bulletin presents it pretty much guarantees that this is exactly what will happen. The folks who set the Doomsday Clock are smart and serious people, and they're worried about legitimate threats. If the clock gets people talking about these issues, that's good. According to today's press conference, the Doomsday clock is now one of the top tend trending topics on Twtter—although I doubt anyone will be Twittering much about it tomorrow.

Let us not pretend, however, that these threats can actually be measured in any meaningful way.