Nine countries have nuclear weapons that could kill millions and plunge the world into a “nuclear winter.”
Matthew Kroenig has witnessed firsthand the growing fear that nuclear war is imminent.
A professor at Georgetown University, he’s taught an undergraduate course on nuclear weapons and world politics for the past decade. He always asks the same question on the last day: How many of his students think they’ll see nuclear weapons used in their lifetime?
For many years, no more than one student would raise their hand. That made sense, he told me, because in those days, “talking about nuclear war was like talking about dinosaurs — it’s just something from the past that won’t be something in our future.”
But the past couple of years have been different. When he asked that question again this spring, roughly 60 percent of his students raised their hands. What’s more, he agrees with them. “If I had to bet at least one nuclear weapon would be used in my lifetime,” says the 40-year-old Kroenig, “my bet would be yes.”
Kroenig and his students are not alone. A January 2018 World Economic Forum survey of 1,000 leaders from government, business, and other industries identified nuclear war as a top threat.
The widespread concern is understandable. Last year, it seemed a nuclear conflict between the US and North Korea was on the horizon. India and Pakistan, two nuclear-armed enemies, could restart their decades-long squabble at any time. And the US and Russia — the world’s foremost nuclear powers — have had warheads pointed at each other since the earliest days of the Cold War.
President Donald Trump’s presence in the Oval Office has increased worries of a potential nuclear war. In January, a poll showed about 52 percent of Americans — many of them Democrats — worried that the president would launch a nuclear attack without reason.
So what is the risk of a nuclear war, really? After speaking with more than a dozen experts familiar with the horrors of nuclear conflict, the answer is that the chances are small — very small.
But that may not be too comforting, says Alexandra Bell, a nuclear expert at the Center for Arms Control and Non-Proliferation. “The chance is not zero because nuclear weapons exist,” she says. And the damage would be incalculable; all it takes is just one strike to conceivably kill hundreds of thousands of people within minutes and perhaps millions more in the following days, weeks, and years.
What’s more, that first strike could trigger a series of events, leading to a widespread famine caused by a rapidly cooling climate that could potentially end civilization as we know it.
Below, then, is a guide to who has nuclear weapons, how they might be used, where they could drop in the future, what happens if they do — and if humanity could survive it.
Nations typically want nuclear weapons for two reasons: self-defense — why would anyone attack a country that could respond with the world’s most destructive bombs? — and global prestige .
Not every government can afford them because nukes take billions of dollars to build, maintain, and launch properly. The proliferation process is also risky, MIT nuclear expert Vipin Narang told me, because seeking a nuke makes a country a potential target. A nuclear bomb-seeking country is typically vulnerable to attack.
Today, only nine countries own the entirety of the roughly 14,500 nuclear weapons on Earth. That’s down from the peak of about 70,300 in 1986, according to an estimate by Hans Kristensen and Robert Norris of the Federation of American Scientists.
Two countries account for the rise and fall in the global nuclear stockpile: Russia and the United States. They currently possess 93 percent of all nuclear weapons, with Moscow holding 6,850 and Washington another 6,450 (which is smaller than the 40,000 that Russia, then known as the Soviet Union, had in the 1980s and the roughly 30,000 the US had in the mid-1960s through mid-70s).
During the Cold War, each side built up its arsenal in a bid to protect itself from the other. Having the ability to attack any major city or strategic military position with a massive bomb, the thinking went, would make the cost of war so high that no one would want to fight.
But two developments in particular led to the precipitous drop, Alex Wellerstein, a nuclear historian at the Stevens Institute of Technology, told me. First, Russia and the US signed a slew of treaties from the 1970s onward to reduce and cap parts of their nuclear programs. Second, both sides learned to hit targets with extreme precision. That negated the need for so many bombs to obliterate a target.
The US and Russia, though, still maintain thousands of nuclear weapons while the other seven countries — the UK, France, China, Israel, India, Pakistan, and North Korea — have no more than a few hundred. Still, every country has more than enough weapons to cause suffering on a scale never seen in human history.
The question, then, is not just who might actually use the weapons they own, but how? It turns out it’s a lot easier to launch than you might want to believe.
The way leaders could launch their nuclear weapons vary.
For example, North Korean leader Kim Jong Un could likely order one without any checks on his authority. Russian President Vladimir Putin, meanwhile, would put the country’s forces on high alert if it detected an incoming nuclear-tipped missile, Russian forces expert Pavel Podvig told me.
The Russian military could respond in kind if troops noted a loss of communication with Putin and it confirmed nuclear detonations elsewhere in the country, Podvig added. While we can’t say for certain what Putin would do, it is definitely possible that he would order a nuclear strike first if he felt he needed to.
Still, he says Moscow would only respond to being attacked. “Only when we become convinced that there is an incoming attack on the territory of Russia, and that happens within seconds, only after that we would launch a retaliatory strike,” Putin said during a conference in Sochi on October 18.
And if Trump decided to attack, say, North Korea with a nuclear bomb, it would be hard to stop him from doing so because he has complete authority over the launching process.
“The president can order a nuclear strike in about the time it takes to write a tweet,” Joe Cirincione, the president of the Ploughshares Fund, a foundation that works to stop the spread of nuclear weapons, told Vox’s Lindsay Maizland in August 2017.
Here’s how the American system works:
1) The president decides a nuclear strike is necessary
It’s unlikely that the United States would turn to nuclear weapons as a first resort in a conflict. There are plenty of nonnuclear options available — such as launching airstrikes to try to take out an adversary’s nuclear arsenal.
But the United States has consistently refused to adopt a “no first use” policy — a policy not to be the first one in a conflict to use a nuclear weapon, and to use them only if the other side uses them first. That means Trump could theoretically decide to launch a nuclear strike before an adversary’s nukes go off in America.
In the heat of battle, the US military might detect an incoming nuclear attack from North Korea and the president could decide to respond with a similar strike.
Either way, the president is the one who ultimately decides to put the process of launching a nuclear strike in motion — but he still has a few steps to complete.
2) A US military officer opens the “football”
Once the president has decided the situation requires a nuclear strike, the military officer who is always by the president’s side opens the “football.” The leather-clad case contains an outline of the nuclear options available to the president — including possible targets, like military installations or cities, that the US’s roughly 800 nuclear weapons ready to launch within minutes can hit — and instructions for contacting US military commanders and giving them orders to launch the missiles with warheads on them.
3) Trump talks with military and civilian advisers
The president is the sole decision-maker, but he would consult with civilian and military advisers before he issues the order to launch a nuclear weapon.
A key person Trump must talk to is the Pentagon’s deputy director of operations in charge of the National Military Command Center, or “war room,” the heart of the Defense Department that directs nuclear command and control.
The president can include whomever else he wants in the conversation. He would almost certainly consult Gen. John Hyten, commander of US Strategic Command, since Hyten is responsible for knowing what the US can hit with its nuclear weapons. But Trump would likely also include Defense Secretary James Mattis, National Security Adviser John Bolton, and Gen. Joseph Dunford, chairman of the Joint Chiefs of Staff, in that conversation as well.
The chat also doesn’t have to be held in the White House’s Situation Room; it can happen anywhere over a secured phone line.
If any of the advisers felt such an attack would be illegal — like if Trump simply wanted to nuke Pyongyang despite no apparent threat — they could advise the president against going ahead with the strike.
Last November, Hyten publicly said he wouldn’t accept an illegal order from Trump to launch a nuclear attack. “He’ll tell me what to do, and if it’s illegal, guess what’s going to happen?” Hyten told an audience at the Halifax International Security Forum last year. “I’m gonna say, ‘Mr. President, that’s illegal.’”
He continued by outlining what the military could consider an illegal order: if a nuclear attack isn’t proportional to the actual threat, for instance, or if the attack would cause unnecessary suffering. However, what does and doesn’t constitute a “legal” order is still up for debate and was the focus of a congressional hearing last November.
Either way, if Hyten refused to follow the order, Trump could fire him and replace him with someone who would carry it out.
4) The president gives the official order to strike
After the conversation, a senior officer in the “war room” has to formally verify that the command is coming from the president. The officers recite a code — “Bravo Charlie,” for example — and the president must then respond with a code printed on the “biscuit,” the card with the codes on it.
Then members of the “war room” communicate with the people who will initiate and launch the attack. Depending on the plan chosen by the president, the command will go to US crews operating the submarines carrying nuclear missiles, warplanes that can drop nuclear bombs, or troops overseeing intercontinental ballistic missiles on land.
5) Launch crews prepare to attack
The launch crews receive the plan and prepare for attack. This involves unlocking various safes, entering a series of codes, and turning keys to launch the missiles. Crews must “execute the order, not question it,” Cirincione told Maizland.
6) Missiles fly toward the enemy
It could take as little as five minutes for intercontinental ballistic missiles to launch from the time the president officially orders a strike. Missiles launched from submarines take about 15 minutes.
And then the president waits to see if they hit their target.
Those that have nuclear weapons, many have argued, will never use them. The destruction and human devastation is so unimaginable that it’s hard to believe a world leader will launch them again, they say. But no one can guarantee they won’t be used at least once more — and that possibility keeps most nuclear experts up at night.
They disagree wildly as to what the next nuclear use might look like or how it might happen, but they almost unanimously cite the same three risks.
The potential nuclear conflict between the United States and North Korea worries most experts — and likely most people on Earth.
That makes sense: Trump and Kim, the North Korean premier, spent most of 2017 threatening to bomb each other with nuclear weapons. Kim actually gained a missile capable enough of reaching the entirety of the United States, although questions remain about whether it could make it all the way with a warhead on top and detonate.
Still, there remains a genuine fear — perhaps slightly allayed now following Washington and Pyongyang’s diplomatic thaw — that the leaders might escalate their public squabble into a nuclear conflict.
In February, Yochi Dreazen wrote for Vox that “a full-blown war with North Korea wouldn’t be as bad as you think. It would be much, much worse,” in part because “millions — plural — would die.”
As Dreazen recounts, the US would likely have to send in around 200,000 troops to destroy Kim’s nuclear arsenal. Seoul, South Korea’s capital, would soon — if not already — lie in ruins due to North Korea’s large artillery capabilities.
None of that may even be the worst part:
In effect, any attempt to overthrow the Kim regime would prompt North Korea to launch nukes at the United States. Washington would almost certainly respond in kind, leading to one of the worst wars in world history.
Few experts discounted the idea that the US and Russia could yet engage in a nuclear war despite a decades-long standoff. After all, they’ve come close a few times.
Here are just two examples: In September 1983, a missile attack system made it seem like the US had launched weapons at the Soviet Union. One man, Soviet Lt. Col. Stanislav Petrov, decided it was a false alarm and didn’t report the alert. Had he done so, Moscow likely would’ve responded with an actual nuclear strike.
Two months later, a too-real NATO war game — Able Archer 83 — made the Soviets believe Western forces were preparing for an actual attack. Moscow put its nuclear arsenal on high alert, but ultimately, neither side came to nuclear blows.
Today, two main reasons explain why a US-Russia nuclear fight is a major concern.
The first is the most obvious: Moscow just has so many nuclear weapons. Russia is the only country that could match the US bomb-for-bomb in any conflict. The longer Moscow has its weapons, the thinking goes, the higher the chance it uses them on the US — or vice versa.
The second reason is the most troublesome: Washington and Moscow may be on a collision course. Russia is expanding further into Europe and encroaching on NATO territory. There’s even fear that Putin might authorize an invasion of a Baltic country that once was a part of the Soviet Union but is now in NATO. If that happens, the US would be treaty-bound to defend the Baltic country, almost assuredly setting up a shooting war with Moscow.
Experts disagree on what would happen next. Some, including the Trump administration, claim Russia would use nuclear weapons early in a fight as a way to “escalate to deescalate” — do something so brash at the start of a conflict that it has to end before it gets even worse. Others say Russia would use the weapons only if its forces are on the brink of defeat.
But Olga Oliker and Andrey Baklitskiy, experts on Russia’s nuclear strategy, wrote at War on the Rocks in February that Moscow’s “military doctrine clearly states that nuclear weapons will be used only in response to an adversary using nuclear or other weapons of mass destruction,” or if the country’s survival is in doubt.
