Five Ways to Start a Nuclear War

Published Feb 18, 2020

Physicist David Wright discusses the nuclear weapons policies and scenarios that threaten our safety, and how to mitigate those risks.

In this episode
  • Colleen and David talk nuclear weapons
  • David explains how we assess nuclear risks and decide how to respond
  • We all try not to lose sleep at night worrying about the existential threat of nuclear war
Timing and cues
  • Opener (0:00-0:55)
  • Intro (0:55-2:36)
  • Interview part 1(2:36-13:23)
  • Break (13:23-14:12)
  • Interview part 2 (14:12-23:32)
  • Sidelining Science Throw (23:32-23:46)
  • Sidelining Science (23:46-27:25)
  • Outro (27:25-28:24)
Related content
Show credits

Sidelining Science: Shreya Durvasula
Editing and music: Brian Middleton
Research and writing: Jiayu Liang and Pamela Worth
Executive producer: Rich Hayes
Host: Colleen MacDonald

Full transcript

Colleen: David, welcome back to the podcast.

David: It's really nice to be here.

Colleen: So I was thinking recently because I did watch a few of the old nuclear, Cold War, apocalyptic movies and, you know, when I think about nuclear war, that's what comes to mind. There are these Cold War-era visuals. You've got a large mushroom cloud with devastating force and cities are reduced to rubble and your basic post-apocalyptic landscape of utter destruction. I mean, that's what comes to mind but I feel like the world has changed and I'm wondering I mean, how could we get into a situation where nuclear weapons might actually be used? And that's where you come in. So David, what are some of the scenarios that could lead us from the present to an exchange that results in some sort of apocalyptic future?

David: Well, let me just say I think it's an important thing to think about because you wanna be able to think about how these things might start to figure out how to keep them from starting. And the thing that people tend to think about is, you know, a big exchange between the U.S. and the Soviet Union or the U.S. and Russia. Deterrence is pretty strong. That's hard to get going sometimes. And so we've been thinking pretty carefully about other ways that things might start and I've sort of outlined five that I think are particularly interesting to think about. We can go into these in detail but let me just run through them quickly. The most likely way that many people think a nuclear war could start is by mistake and we can talk about that.

My second sort of in the list is nuclear war starting because of ambiguity and, again, this is something that is not what people tend to think about. There is...since the Cold War, there's been ideas of trying to use small nuclear weapons on the battlefield to try to keep a nuclear exchange limited, to have nuclear war fighting on the battlefield. And so that's one of the ways you can imagine it would get out of hand.

The other two are more standard things that people think about. You know, what might happen with a crisis with North Korea for example? And finally, what might happen in South Asia as a consequence of a conventional war between India and Pakistan for example? So those are sort of five things I've been thinking about.

Colleen: I think your first one, a mistake, is...well, let's just say the movie festival that I just had. The majority of the scenarios were a mistake. We thought they launched it, they thought we launched it, and there's no coming back.

David: That's not far from the kind of scenarios we're thinking about. Only the policies that the U.S. has in place actually makes it more likely that'll happen. So, in particular, when I say a nuclear war could start by mistake, it would be because of a nuclear launch as a result of a false warning. So you think that there's an incoming attack, you launch in response, and then you find out that, in fact, your warning was wrong.

Now, that's particularly a problem because the United States currently has 400 land-based missiles and it keeps them on high alert or as we sometimes call it, hair-trigger alert. The scenario there is that since those land-based missiles sit in silos, they're at known locations, then they could be vulnerable to an enemy attack unless you have warning and could launch them very quickly. If you had warning of an attack before the attack landed, that does several things. One is it means you have to have a very streamlined and rushed decision process to assess the warning you get and to have the president make a decision. And in most timelines, that means the president would have probably well under 10 minutes to make a decision based on what he or she was hearing about whether to launch.

And the problem, of course, is that the systems that are giving you the warnings, which are radar sensors, satellite sensors, that all goes through computers and gets processed. That's all fallible. And so both by, you know, technical and human errors, this can lead to a problem and we've seen this any number of times historically. The one I think is probably most interesting...it was in November of 1979. All of a sudden, the big board at NORAD where they're watching, you know, for an incoming attack lit up with what looked like an all-out Soviet attack on the United States. And it looked just like the kinds of things they had been planning against. I mean, all the details were there.

So they responded. They got nuclear bombers off the ground. They got fighters in the air. They did all sorts of things. Eventually, they figured out that they weren't seeing some of the warnings from radars as that they would've expected and so they slowly came to the conclusion that it was a mistake and they sort of stood down.

But it was later discovered that somehow...and people actually still don't understand how this happened, a training tape that was in a computer at NORAD, somehow the content of that tape got to the main boards. So this is one of these cases when you have very complicated systems. Things happen and...

Colleen: And it was just as expected.

David: It was just as expected.

Colleen: Because, in fact, it was the training tape they had seen.

David: It looked just like the real thing. So, you know, that's an example of the kind of thing that can happen. On the website, we have a number of other examples to show that both countries have had this kind of thing happen. And the problem, of course, is if the United States thought there was a launch, launched its missiles against the Soviets then or the Russians now, that would certainly cause them to retaliate with a large attack. And so you've now gotten yourself into a really bad situation.

As I said, part of what the problem with this is is that by having land-based missiles, by worrying about their vulnerability, by dealing with that vulnerability by wanting to be able to have the option of launching them very quickly, you've put into place this really streamlined and rushed decision process for assessing the warning and deciding whether or not to launch.

And what's crazy about it is it's actually unnecessary. During the Cold War, the United States and Russia both relied on land-based missiles for their deterrent and so they were very worried about making sure that they couldn't be attacked. But today, the bulk of U.S. nuclear missiles are in submarines that are hidden away at sea. They're very accurate, in fact, more accurate than land-based missiles now. And the U.S. has spent a lot of money and effort making sure that they can reliably communicate with those submarines in a time of crisis. So if you're thinking about deterrents, that really says, you know, you can wait to see what happens if you've got ambiguous warning. And you're still gonna have this massive nuclear force at sea.

So one of the questions is why don't you just get rid of the land-based missiles? And that's one of the things we're looking at. People, I think, typically assume that there are good security reasons for everything that the military does. It turns out...I hate to disappoint people but that's not always true. The three main reasons for keeping land-based missiles are one is... there's what I would call dogma about the nuclear triad that you should really have three legs of a nuclear triad, land-based missiles, submarine-based missiles, and bombers. But if one of those legs is not needed which, I don't think it is and, in fact, is dangerous, then I think that's not a good plan and I think that has to be rethought.

Colleen: So what about some of the other scenarios?

David: The second scenario is the one I call the ambiguity scenario. And people refer to it as conventional nuclear entanglement in a crisis and let me just say what that means. Suppose a conventional war starts. As far as we know, the United States, Russia, and China and probably other countries all have doctrines that call for attacking the communication nodes of the other side, command and control centers, warning sensors, all sorts of things that can be used for conventional forces. That makes a lot of sense. That's what you'd expect would happen. And the problem is that the U.S. Pentagon uses some of those same systems both for conventional and nuclear forces. So they're what we call dual use.

And so that in some sense entangles conventional and nuclear forces. If you're in a crisis and an adversary attacked those facilities as part of their conventional warfighting strategy, depending on the situation, the United States may think that this, in fact, was trying to cripple our ability to respond in a nuclear way, that they were planning a nuclear attack, and that we better go first while we still have the capability to order an attack.

So there is this concern, again, in the midst of a crisis where you don't really know what's going on. There's not a lot of information. Confusion is rampant, that you have to make assumptions about what the other side is doing. And once you start crippling key components of your nuclear forces, people start to worry about what that will happen.

One of the concerning things to me is that this dynamic has actually been seen in U.S. war games. The U.S. military relies really heavily on satellites for communication, for warning, things like that and expects that an adversary would target them early in a conflict.

The United States, China, and Russia are all working on antisatellite weapons, which would be able to attack those. And so we've actually seen in Pentagon war games is that if the red team attacks the U.S. satellites early in a crisis and the U.S. forces lose the ability to communicate and do the things they wanna do, that these will actually lead to the United States launching a nuclear attack in these war games.

So again, this is both one of the things that sort of makes sense if you think about it but we've actually sort of seen it play out the way the Pentagon does these games to see what people would do in a situation like that.

The third case, which is actually quite relevant these days, the idea of using limited tactical nuclear weapons on the battlefield and have that escalate. So the U.S. and Soviet Union, now Russia, have long had what are called tactical nuclear weapons. So the long-range strategic nuclear weapons, sort of intercontinental-range missile, typically a very large yield. Tactical weapons have shorter ranges and they have much smaller explosive yields. So, for example, the United States has tactical weapons with yields as low as one-fiftieth of the bomb that we dropped on Hiroshima. The hope was that you could actually use it for an advantage on the battlefield without escalating to a large-scale war.

Now, the problem is nobody knows if that's true. And again, when you think about what happens in a crisis when you start, you know, seeing that nuclear weapons have been used, you don't know what the next step is. A lot of military people who have looked at this basically say, "We have no reason in the world to believe that a situation like this would, in fact, stay limited." And so you can easily imagine that that would get out of control and lead to, you know, a major exchange between the countries.

[Break]

Colleen: So where does North Korea, India, Pakistan... How have these smaller countries with weapon changed the playing field?

David: Well, a lot of people have been looking at that. If you go from a bipolar world to a multipolar world, how does that affect things? And I think North Korea is one of the, you know, real concerns people have in the following sense. They have now tested nuclear weapons underground. So we know they have the capability to explode nuclear weapons. The last one they exploded was actually a very good size. It was large. It was probably 10, 20 times bigger than the Hiroshima bomb. And the concern I think that people have is not that North Korea would just someday decide they're gonna indiscriminately lob a nuclear weapon at, you know, Japan or South Korea or the U.S. Unless there's something that really forces North Korea's hand, I think it's unlikely that they would resort to this partly out of self-preservation.

The India and Pakistan case, which is sort of my fifth example, is another case that people worry about. Both India and Pakistan since the 1990s have had nuclear weapons and have been developing aircraft and ballistic missiles to deliver them. And, you know, these are two countries that have a long-standing animosity and have had a number of conventional wars. And so the concern is, again, sort of as a throwback to what happened in, you know, NATO in the Cold War is that when Pakistan looks at the Indian army, they see themselves as having a conventional inferiority. And so one of the things that they have talked about from time to time is using nuclear weapons to stop a Indian invasion, a conventional Indian invasion. And, again, the question is how they would use those, what the response of India would be. You know, the hope is that this would not spread beyond South Asia but there have been interesting studies that had been done looking at the climactic effects of nuclear use.

So-called nuclear winter issue that people have talked about since Carl Sagan and others a long time ago. Modern climate models have shown that, in fact, nuclear winter is real if you put enough dirt and soot in the high atmosphere to block out the sun. And I think there's no doubt that a large attack between the U.S. and Russia, for example, would do that, would put enough material in the atmosphere. What's been surprising is that people have looked at more limited attacks and one of the examples was an exchange of a hundred nuclear weapons between India and Pakistan. And again, there are questions about exactly what they target. If you targeted cities, how much of it would burn, how much of that carbon would get into the atmosphere?

But there are realistic scenarios where you can imagine that, in fact, that kind of a limited exchange between India and Pakistan could cause very severe cooling for a decade or more, could lead to problems with food shortages. And I think the Physicians for Social Responsibility did a study where they found that, you know, upwards of a billion to two billion people could die as a result of disease and famine. So again, you're talking about something which is usually thought of as a regional problem becoming a very big global problem.

Colleen: Right, well that was one of my thoughts. What are the environmental impacts that we might see in a smaller exchange?

David: So I haven’t seen good estimates of the radiation clouds from those. If you’re talking about a situation where you’re getting a lot of soot and other things into the upper atmosphere, you’re clearly putting radioactive material up that far, and that’s going to be distributed well around the universe... Or well around the globe. But I think by far the bigger concern would be really the potential climactic effects. Because that really, if it changed the climate dramatically, in a short amount of time, could have a huge effect on a large number of people. And it’s interesting, it’s one of the reasons, people talked about a couple years ago, the United Nations adopted the nuclear ban treaty which basically would outlaw nuclear weapons in the same way that chemical and biological weapons are outlawed. The United States and other nuclear countries haven’t signed that yet. But part of the reason this is such a big issue to the rest of the world is that they feel like to some extent they're being held hostage by the possibility that the nuclear weapons states could use nuclear weapons at a point to cause, really, global disaster that would affect all of them. So I think the idea that somehow this is just an issue that the nuclear weapon states should be thinking about and that somehow these other countries shouldn’t be involved and let the big boys, you know, deal with it... clearly when you start thinking about these global effects, doesn’t make any sense.

Colleen: So David, what are your top three or five solutions to get us in better shape so that we aren't in a nuclear weapon crisis mode, to slow things down and get our leaders to be more thoughtful?

David: We have spent a lot of time thinking about, you know, the path forward. How do you get from where we are to a safer future? And I tend to think of dividing that into several pieces. Things you could do very quickly, that the United States, for example, could do very quickly on its own, wouldn't have to negotiate with other countries. And those include things like changing its own policy, having a no-first-use policy, taking land-based missiles off hair-trigger alert and getting rid of a launch on warning policy. Even things like currently, the U.S. president has sole authority to decide to launch nuclear weapons to...you know, there are ways that people have...and we have done some of this work, have proposed to add other people to that decision tree. So there are things that the United States could do tomorrow basically that I think would address some of the key things that I've talked about here today.

The other sort of no-brainer is arms control. I mean, the advantage of arms control is not only that it gets people talking to one another and puts limits on what they can do but it also...you know, the treaties we have set up very significant verification and transparency measures so...

Colleen: So this is talking on an international level and getting other countries to agree to a set of rules.

David: Right. And so, you know, to start with, we, the United States and Soviets and now the United States and Russia have done a number of bilateral treaties. So the first thing is to save some of those treaties and the Trump administration has pulled out of a couple of those treaties recently. The new Start Treaty, which limits the deployment of long-range strategic weapons by both sides, is coming to the end of its lifetime. Part of the original agreement was that the two countries could agree sort of with no further negotiation to extend it for five years. President Putin of Russia has said that he would like to do that. And the Trump administration still hasn't responded to that.

So from my point of view, that, as I said, not only sort of says that countries think that arms control's a good idea but it would keep in place these very strict verification transparency measures that are really important for both countries continuing to talk to each other and seeing what each other has.

Colleen: And what's the deadline on that?

David: It's just after the new president would take office. So just after...some time I think in early February 2021. And so, you know, there is some time for that but that really should be a no-brainer.

Colleen: So are these treaties mainly between the U.S. and Russia or is China a player or are there other countries that are involved in these discussions?

David: In general, I think one of the things you'd like to do with more sort of negotiations and discussions internationally is to bring in other countries like China. It's gonna be hard to get them to be part of a treaty like the Start Treaty because their arsenal is much smaller than the U.S. and Russian arsenals. And so it's a little hard to know how to fit them into that. But I think the idea of starting serious discussions about these issues with China is just really important in part because as we talked about, you know, this notion of crisis stability and if things heat up not really knowing what the other side is doing, what the other side is thinking, not having good communication channels to be able to try and get ahold of your counterpart and figure things out, you know, to take the temperature down, those are all things that really matter when you're in a crisis. And so the fact that that's not happening in a very serious way at this point is something that I think is concerning.

Colleen: Well, David, thanks for joining me on the podcast. Not a happy topic but I was happy to hear that you had some no-brainer solutions. So there's some good news.

David: Well, I think once you can identify the ways to get into them, you can identify ways to stop them and that's really what we're spending our effort on.

Colleen: Great. Well, thank you.

David: Thank you.

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