Nuclear weapons are something so scary and so dangerous — thousands of weapons explicitly designed to be powerful enough to destroy the world many times over, perpetually deployed, and able to be fired with the push of a few buttons, like a gun forever left to the world's head — that I'm sometimes amazed at how little we talk about them.
There are a few reasons for that. One is that they're so big and scary it can be difficult for people to wrap their heads around. Another is that there's an impression — not entirely true, as I'll explain — that nothing ever changes with nukes, so we're just in a peaceful status quo. But another is just that the scale of the threat still posed by nukes might not be obvious to everyone.
So it's worth laying that out, as this three-minute cartoon by the popular series Minute Physics does. It's a good overview, and more than a little scary:
As Max Tegmark of MIT explains in the video, the real risk of nukes is that they'll be set off in some sort of mistake.
But — and this is important — when experts like Tegmark talk about the mistaken use of nuclear weapons, they're not talking about a random or otherwise accidental detonation (although that has almost happened a few times). Rather, they're talking about geopolitical tensions between nuclear-armed powers that, by some confusion or unintended escalation, could become a nuclear exchange before anyone realized it was all a big misunderstanding.
There are two general ways that could happen.
The first are the sorts of incidents Tegmark goes through in the video: One side misperceives the other as launching a nuclear weapon. Because nuclear weapons take only minutes to deliver, the side that believes it is under attack has only minutes to respond — not enough time to investigate what's happening before retaliating.
As Tegmark explains, this has happened a few times. Blessedly, thankfully, when faulty readings led one side to believe it was under nuclear attack, the people on that side simply chose not to follow the rules requiring them to retaliate. The 1983 incident he cites (which I retell in full here) was probably the closest we ever came to total nuclear annihilation, avoided because the Soviet lieutenant colonel on duty refused to follow protocol requiring him to retaliate.
The second way this could happen is that an actual conflict could break out between two nuclear powers. As this conflict escalated, each side would watch the other obsessively for any sign of a nuclear strike. And some countries, such as Russia, have rules allowing their militaries to use nuclear weapons, in certain circumstances, even if the other side has not.
Again, because the logic of nuclear weapons requires a lightning-fast retaliation to any nuclear launch, there would be dozens of ways in which the two sides could misread some action or escalation as the start of a nuclear attack, and launch what they believe is a retaliation (meant to return in kind and thus prevent more strikes) but would actually be a first strike.
So why do we still have these things if they put us in a state of constant, if low-level, risk of global annihilation? Tegmark makes it sound like the answer is money from defense contractors, but I'm not sure it's so simple. (It's not like Northrop Grumman existed in the communist Soviet Union, which long resisted nuclear disarmament.)
The challenge is this: Both American and Soviet/Russia leaders have expressed a desire to reduce their own stockpiles, but they only want to do it if the other side reciprocates in turn. They want to maintain the strategic balance between their two countries' nuclear arsenals, and they also know that if they disarm unilaterally, they'll lose leverage to get the other side to disarm.
So disarmament happens jointly, in painstakingly negotiated agreements, which also include painstakingly negotiated inspections and monitoring regimes to make sure the other side is holding to their end. That is extremely difficult and time-consuming even in periods of relative friendliness between Moscow and Washington. But in periods of tension — right now, for example — the distrust is just too high, and the domestic politics within both countries make such agreements too politically costly anyway.
The upshot of all this is that we're left, more or less perpetually, in a Cold War–era status quo, in which both the US and Russia have enough nuclear weapons to destroy the world many times over, have nuclear war plans that require doing exactly that, and have forward-deployed those warheads in a way that is meant to deter the other side but also substantially increases the risk of unintended conflict by reducing our response time to mere minutes.
That's the status quo, and it's pretty bad. But it gets worse, because the status quo isn't really static.
Military technology is constantly changing, and both sides are constantly making upgrades that require the other side to upgrade in turn. So, for example, the US develops a new stealth fighter jet and bomber, which leads Russia to develop better air defense systems.
But the problem is that these changes also affect nuclear weapons technology, which means the carefully balanced nuclear equilibrium is constantly being destabilized.
Take, for example, those improved Russian air defense systems. The American nuclear deterrent is designed to have three components — submarines, bombers, and land-based missiles — known as the triad. Russia's new air defenses make the air-based part of our triad weaker. So to maintain parity, we are developing a new air-launched cruise missile that can carry nuclear weapons.
But this new weapon, by maintaining parity in some respects (ability to penetrate air defenses), destabilizes parity on others (it reduces Russia's response time and could be perceived as a first-strike weapon). At the same time, this weapon increases the risk that a conventional conflict with Russia could spiral into an unwanted nuclear exchange, because Moscow would be unable to differentiate a conventional cruise missile from a nuclear cruise missile.
This is all a very long way (sorry, I get carried away on this topic) of saying that this video describes the threats of nuclear weapons well but, if anything, significantly understates those threats.
This all speaks to what you could maybe call the biggest myth about nuclear weapons, which is that we're in a peaceful stasis, with parity between the US and Russian forces providing stability. In fact, both sides are constantly doing things to manage that parity that also involve disturbing it, sometimes in ways that can be destabilizing and can increase the risk of an accident, misunderstanding, or unintended escalation. That risk is extremely low and the increases are marginal, but given the potential consequences — the literal end of the world — it's still pretty scary stuff.