Science Friday - 40 Years Of Sounding The Alarm On Nuclear Winter

Episode Date: November 6, 2023

This week holds anniversaries for two important milestones in nuclear warfare. On November 1, 1952, the United States detonated a massive hydrogen bomb in the Marshall Islands. The new weapon vaporized a whole island, leaving behind a mile-wide crater. That bomb was around 700 times more powerful than the one dropped on Hiroshima seven years prior, and it renewed fears of nuclear annihilation, which would grip the world for generations to come.Three decades later, on October 30, 1983, millions of Americans flipped open the Sunday paper to find a shadowy, apocalyptic photo with the words: “Would nuclear war be the end of the world?”Legendary scientist Dr. Carl Sagan, writing for Parade Magazine, introduced the world to “nuclear winter,” the terrifying climate changes that might be brought on by nuclear war.Sagan conducted some of the first research on nuclear winter, and he spent years warning politicians, world leaders, and the general public about it. Today, with thousands of nuclear weapons still in existence, the risk of nuclear winter isn’t zero.Ira talks with another pioneer in nuclear winter research, Dr. Alan Robock, a climate scientist and distinguished professor at Rutgers University, about the science of nuclear winter, how fear of those consequences shaped policies, and what’s happening with the world’s nuclear arsenal now.To stay updated on all things science, sign up for Science Friday's newsletters. Transcripts for each segment will be available the week after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

40 years ago, scientists sounded the alarm on nuclear winter, and it changed the world. Once you saved the world from nuclear weapons, what do you do with the rest of your life? It's Monday, November 6th, but you guessed it, it's actually Science Friday. I'm sci-fri producer Rasha Irredi. In honor of this 40-year anniversary, Ira talks with someone whose work on nuclear winter went on to influence nuclear policy, and it changed the course of nuclear warfare. forever. This week holds anniversaries for two important milestones in nuclear warfare. In November 1952, 71 years ago, the U.S. detonated a terrible new weapon, a massive hydrogen bomb in the Marshall Islands.

It vaporized a whole island, leaving behind a mile-wide crater where the island once was. It was around 700 times more powerful than the bomb dropped on Hiroshima. Fast forward to almost 40 years. ago today, on October 30, 1983, millions of Americans flipped open the Sunday paper to find a shadowy gray, very apocalyptic photo with the words, would nuclear war be the end of the world? It introduced the world to nuclear winter, the terrifying climate changes that might be brought on by nuclear war. And it was the iconic scientist, Carl Sagan, that introduced the term. He was an author of the first research on nuclear winter spent years warning politicians, world leaders, and the general public. The idea that more nuclear weapons make you safer is an illusion.

Beyond a certain point, more nuclear weapons make you less safe. The threat of nuclear winter has reduced since then, but with thousands of nuclear weapons still in existence, that risk is not zero. My next guest is also a pioneer in nuclear winter research. Dr. Alan Robuck, climate scientist and distinguished professor at Rutgers University based in New Brunswick, New Jersey. Welcome back to Science Friday. Thanks very much for having me. By the way, I want to correct one thing. The threat of nuclear winter has not gone down.

It's still with us. Why is that? Nuclear winter would be caused by smoke from fires started by nuclear weapons dropped on targets. And there are still way too many nuclear weapons in the world. There are enough to produce that much smoke and to produce nuclear winter today, even though the Russian and American arsenals, which make up more than 90% of the world arsenals, have been going down.

Tell us about the details. Give us an idea for people who did not live through those times like you and I did, talking about nuclear winter. What does that definition mean? If a nuclear war was held and bombs were targeted on cities, they would burn and produce lots of smoke. And the smoke would go up into the atmosphere and maybe 3% or so of the material,

burn would turn into smoke and it would go up to the upper part of the troposphere, which is where we live, but sun would heat it and loft it into the stratosphere, which is a layer above that. In the stratosphere, there's no rain to wash the particles out, and they would last for years. Particles in the lower atmosphere last for a week or so. And so if you calculate how much smoke there would be, it would last for many years and be blown around the world and absorbed sunlight and make it cold and dark at the earth's surface. temperatures could get below freezing even in the summertime in the middle of continents. That's nuclear winter.

Take us back to 1983. Let's talk about the social and political atmosphere there. What was happening at that point in nuclear history? There was still an arms race. Everybody was worried about a nuclear war between the U.S. and the Soviet Union. And there were massive demonstrations to try and ban the bomb, get rid of nuclear weapons. And this was in democracies in the United States and in England in particular. At the same time, a group of scientists in California calculated how much smoke there would be

and what would be the effects if there was a nuclear war. And they published a paper in 1983. The Parade Magazine article you mentioned was written by Carl and came out of before the actual journal article in the journal science. And it said there would be nuclear winter if there was a nuclear war. That was pretty shocking to people. Nobody had looked at these indirect effects of nuclear war. Everybody knew how horrific the direct effects would be blast, fire, radioactivity, but nobody had looked at these indirect effects before.

Yeah, and that Parade Magazine, and I think that was the most popular magazine in the country because everybody got it bundled with their Sunday newspaper. That really did catch attention, right? People really paid attention to that. Absolutely. I was at the University of Maryland then, and there was a two-day workshop. shop at the Shoreham Hotel in Washington, D.C., about this, where Carl came in. But there was also a satellite connection to Moscow, and there were some Russian scientists,

Alexandrov and Stentikov, who had done the same calculation. In fact, their paper was published a week before the Taps paper, the nuclear winter paper. But they got the same result. If you put that much smoke in the atmosphere, it would get cold and dark at the Earth's surface. And so they were talking about it from Russia, and Americans were talking about it. And that also got a lot of publicity. And if I recall at that time, that's important that you got similar results and, you know, could not be considered propaganda by one country or the other.

Absolutely. I was part of the Soviet-American scientific exchange, and we met Russians and worked with Russians, and we scientists have a lot in common. So it was collaborative, and it was useful to work with multiple people. So a couple years later, Mikhail Gorbachev and Ronald Reagan met in Iceland to discuss what to do about the nuclear arms race. And they were both quoted as saying that they listened to the scientists from both sides and accepted the science because it was not propaganda.

Ronald Reagan said, a great many reputable scientists are telling us that such a war would end up in no victory for anyone because we'd wipe out the earth as we know it. So he'd call me reputable. But how refreshing it is to hear that politicians listen to scientists? Absolutely. And Gorbachev said models made by Russian and Americans. American scientists showed that a nuclear war would result in a nuclear winter that would be extremely

destructive to all life on Earth. So I think we played a role in helping convince them to stop the arms race and start reducing the arms race. They realized that we had way too many weapons already and Breland Moore was going to make us less safe, not safer. You must still get some satisfaction on that contribution. I do. I mean, once you've saved the world from nuclear weapons, what do you do with the rest of your life. Well, one thing you did is last year, your study in nature food looked at the famine that could come again from nuclear winter. How many people today would that affect?

So the number of weapons started going down in the 1980s, and it kept going down, but it didn't stop going down. There's still about 10,000 nuclear weapons in the world. And then for the last decade, they really haven't gone down at all. So people said, okay, so there's weapons, there's smoke. How would it affect food? And so we calculated how much smoke there would be from different scenarios of a war between India and Pakistan or U.S. and Russia and how much it would affect the temperature, the precipitation, the amount of sunlight.

And we calculated with a crop model how the major crops would grow in every country around the world. And what we found is a war between India and Pakistan could produce famine in the next year, could kill one to two billion people. Wow. A war between the U.S. and Russia could kill more than five billion people, most of the people in the world. It places far removed from the war where there were no bombs dropped. This is the indirect effect.

So it wouldn't even take an all-out war between Russia and U.S. to kill a billion or so people. That's right. And so that paper got a lot of attention because of those dramatic results. Nobody had actually calculated directly what the effects would be on food. We use data from the Food and Agricultural Organization, F-A-O for every country. What do they grow? What do they eat?

How much do they import and export? We assume that trade would stop, you know, like we hoarded toilet paper during the pandemic. People would keep their food. So a few countries that don't have many people that are big exporters now would have enough food, places like Argentina or Australia. But, you know, if you think refugees are a problem now, there'd be flotillas of hungry people arriving in their shores. So it's not a decision just to go live there and wait and wait. So, yes, it's still a problem. And we're still doing more work to try and use many more climate models, more crop models and to see how robust our results are.

And the nuclear club, the number of countries that have nuclear weapons, has increased. There are nine countries with nuclear weapons. And that hasn't changed in quite a while. So there's the five permanent members of the UN Security Council, just by chance, the U.S. Russia, England, France, and China. There's India and Pakistan, and there's North Korea, and there's Israel, although Israel doesn't even admit that they have nuclear weapons. So between all of them, how many weapons do you think exist? There are about 12,000 altogether. And some of them in the U.S. and Russian arsenals are not deployed.

They're on shelves. They're sort of waiting to be dismantled. The U.S. and Russia have a treaty called the New Start Treaty, which limits each country to 1550 strategic weapons. Those are on bombers, missiles, and submarines. But each bomber counts is one. So maybe each country has about 2,000 that could be used. But the other countries have a couple hundred. England, France, China, India, Pakistan, Israel, and North Korea might have 40 or so.

So, you know, people claim that what are our weapons for? Oh, we're not going to attack somebody. They're for defense. They're for deterrence. And so I asked them, how many weapons do you need to put on to your enemy's capital to deter them from attacking you? And when I ask audiences that, the answer is often one. Because it would be so horrible. So maybe they need two and the first one doesn't work.

So these countries decided that a couple hundred are more than enough. But the U.S. and Russia still have thousands. So I don't understand why we have so many. Why did you feel it was time in recent history like last year to bring up the topic of nuclear winter again? Was there something going on that you detected? About 15 years ago, Brian Toon and Rich Turko approached me at a conference, the American Geophysical Union meeting, and said somebody asked us what would happen if India and Pakistan had a nuclear war? Because these are two new nuclear nations.

Each one had about 100 weapons at the time. And they calculated how much smoke would come. And it wouldn't be as much as from U.S. and Russia, but it would be more than 5 million tons of smoke. And they asked me to calculate the climate response. I had a student, Luke Oman, who was using our model for looking at volcanic eruptions, which put different sulfur gases up in the stratosphere and not smoke. And so we put it into our model. We found temperatures would cool.

It wouldn't be nuclear winter, but it would be the greatest climate change in recorded human history. would be colder than little ice age, about three degrees Fahrenheit, colder than average. And then we took our climate model. We said, you know, in the 1980s, the climate models, the computers were very primitive. Let's go back and see if it really was nuclear winter because people criticized the models. And we put the smoke in from U.S. and Russia. And sure enough, temperatures got below freezing in the summertime in Iowa, in Ukraine, places which are breadbaskets. It's interesting that you talk about that now, because I think that people of a certain age, my age, your age. We remember the existential threat posed by nuclear weapons. We remember people

talking about nuclear winter. But today, with the Russians rattling their nuclear sabres again in Ukraine, I don't get the sense that people understand just how deadly a threat nuclear weapons pose, if not from the military side, but from the nuclear winter side. Do you feel that also? No. In 2014, the international campaign to abolish nuclear weapons, which is an organization of anti-nuclear organizations, along with Alexander Kempint, Austrian ambassador, organized three international conferences on the humanitarian impact of nuclear weapons. The direct effects, they had Habakashav for people that had been there for the bombings of Hiroshima, Nagasaki, but also these indirect effects of starvation. And more than a, there was one in Norway, one in Mexico, one in Austria. More than 100 nations sent ambassadors sent delegates to it. And they were really concerned. They were really afraid of it. They got it.

And then they went to the United Nations. And in 2017, in the United Nations General Assembly, they passed a treaty to prohibit nuclear weapons. And that treaty came into force after 50 countries ratified it. And now half the countries in the world have signed it, 69 have ratified it. So this is the will of the rest of the world that we want you nuclear nations. to get rid of them. We're afraid. So what you said might be true in the United States when people are concerned about other things

and it hasn't gotten to the top of their list of concerns. But the rest of the world is really afraid about it. And ICANN in 2017 got the Nobel Peace Prize for warning the world about these humanitarian impacts and for getting this treaty passed. This is Science Friday from WNYC Studios. In case you're just joining us, I'm talking with Dr. Allen Roebuck

about the threat of the threat of the United States. nuclear winter. Speaking of prizes, you and other pioneers in nuclear winter work, including Carl Sagan, received the Future of Life Award last year, and basically that's an award for people who save the world. And that must have great meaning to you, because, as you said before, your research helped save humanity. Well, I really haven't saved the world yet because we still have all these nuclear weapons. In the 1980s, after I did my work, I published papers, in nuclear winter, I was up for promotion, and I couldn't get much funding for it, but I couldn't not work on it. It was too important. So I kept working on it. Eventually, I did get promoted,

and so, yeah, it's really rewarding to do something that's, and I met my wife because I was at a conference, I was giving me to talk about nuclear winter. I met Carl Sagan. I met Fidel Castro, who invited me down to Cuba to talk about this. Cuba was one of the first countries to sign the the treaty and prohibition of nuclear weapons. And so it's all connected. So it's been good, nuclear winter has been good for me. You've had a wonderful life, nuclear winter wife, so to speak. One last question before we go. We're currently in another crisis that could change the world as we know it. And I'm talking about climate change. Are there any lessons learned from warning against nuclear winter that we could use today about climate change?

Well, I've been working on climate change my whole career. I'm a climate, climate scientist. The world is gradually warming. We know what's causing it, and we know that the reason we haven't solved the problem is because the fossil fuel companies are so powerful and rich that they stand in the way of switching the world to green energy. The same is the problem with nuclear weapons. The military industrial complex is making trillions of dollars building new weapons. When Obama got the New START treaty signed to get the Senate to agree to ratify, he promised a modernization of our nuclear arsenal. And so now we're spending over a trillion dollars to spend, build more missiles that are going to be buried in the ground out in the West. They're never going to be used.

More submarines, more bombers and weapons. And so companies like Lockheed, Raytheon and Boeing are making lots of money of doing this. and they have lobbyists that are ensuring that people stay afraid and convince them that we need more weapons. And so the opposition is sort of similar, and it's very frustrating that as a lowly college professor, I don't have the money to go out and lobby. But if people would go out and protest, like happened in the 1980s, we could change policy. But people have to get excited about it. I'm glad you're airing this interview so people can learn about this.

But that's the problem. That's with the similarities I see. Is there any hopeful note you can end on here? When Putin threatened to use nuclear weapons that got people's attention, the Oppenheimer movie got people's attention. But when I was in Cuba, when I gave my talk, and it was shown a nationwide television the next day. And when I walked into a hotel to see if I was on TV,

there was a Julia Roberts movie on. And I said, could you change a channel? There I was giving a lecture, which taught me that, intellectually is not the way to do it. You have to touch people's feelings. You need to have a movie with a beautiful scientist from St. Petersburg and a handsome scientist from Oak Ridge. Meanwhile, there's a skirmish on the Kashmary border. So Brian Toon and I have written a book, which we want to get published about dead dinosaurs in nuclear winter. We're trying to get a movie made. We're trying to get people's attention that way rather than just publishing journal

articles, even in places like Scientific American. Well, we'll have you back when that's all done, okay, Alan? That would be great. Thank you. Dr. Ellen Robuck, climate scientist and distinguished professor at Rutgers University-based New Brunswick, New Jersey. That's it for today. We'll be in your feeds again tomorrow with the conversation about how one hospital is trying to improve the care it provides death patients. See you tomorrow. I'm Rasha Uridi.