Before 2015, many scientists knew that a “nuclear winter” theoretically could bring major climate change to the world and create famines in many countries. But it wasn’t until the aftermath of the use of a hundred atomic bombs by Pakistan and India – in what was later named the South Asian Nuclear War – that people everywhere began to comprehend the longer-term, global effects of nuclear exchanges. They then understood, to their horror, that there was no such thing as a strictly “regional” nuclear conflict.

International panels and historians would try with scant success to construct a narrative to explain the unprecedented mass destruction of that summer weekend. The early events of the conflict appear plain enough: Pakistan’s government spent July complaining that India was increasingly engaging in cyber attacks aimed at testing the vulnerability of its neighbor’s nuclear command-and-control computer systems. As tensions mounted, Pakistani troops were dispatched into the Kargil district of the Ladakh region in Jammu and Kashmir — an area officially on India’s side of the “line of control” that divided the restive, mountainous Himalayan state. As with a similar incursion in 1999, India responded with intense air and artillery assaults using conventional weapons.

While other governments urged calm, several major Pakistani government buildings in Karachi, Lahore and Islamabad were destroyed by explosive devices. Indian leaders vehemently denied all culpability. They asserted Pakistani militants or religious extremists likely were trying to take advantage of the latest tumultuous period to provoke a nuclear Armageddon between the rival nations.

Indian Army and paramilitary forces confronted large crowds in the streets of Srinager, the overwhelmingly Islamic summer capital of Kashmir, as well as other large cities in the region. Two Pakistani military officers then sparked an uproar in India’s media: One  said publicly his nation was ready and willing to give field commanders the authority to use arsenals of small, tactical nuclear weapons to repel any invasion of his country by Indian soldiers. Another leaked word to reporters that Pakistan was mulling the option of detonating a “demonstration” nuclear warhead, far above a large Indian city, to prove it had no squeamishness about using the bombs it possessed.

July turned to August, and Indian and Pakistani military forces went on full nuclear alert. In preparation for total war, both sides increased the pace of marrying nuclear warheads with missiles and aircraft so they could be used quickly, if needed. Startling the world, India aired TV and radio messages telling citizens to move to their basements – makeshift shelters where many families had already stored emergency food and water after New Delhi recommended it in 2013.

A high-level team of peace envoys from the U.S., whose jet was heading to the region, was urgently mediating with the two sides by telephone over the Atlantic. Diplomats told a relieved world that tensions between India and her neighbor actually were easing and that more a serious conflict probably could be headed off.

But subsequent events are much less clear. Dozens of missiles in both nations remained on hair-trigger alert, with a strategic “window” of about three minutes for politicians and officers to decide if an early warning sign was a real attack. Then, a monumental wild card: A meteor the size of a refrigerator, it was later determined, shattered Earth’s atmosphere 80,000 feet over Jaipur, a city of 3 million in northwest India. Breaking thousands of windows, it exploded in the sky with a sonic boom and an approximate blast power of 250 kilotons (compared to the 12.5-kiloton bomb that destroyed Hiroshima).

The nuclear phase of the war began just eight minutes after the meteor struck. The connection between the meteor and use of missiles by both countries, if any, remains a topic of endless debate. The exchange of missiles persisted for two full days. Approximately 100 nuclear explosions, centering mainly on urban centers, took millions of lives in each country on account of the blasts themselves but also the radiation, hunger and disease that followed. No clear winner emerged.

The significance of the war for the rest of the world soon dawned. After massive pillars of black smoke and dust rose above the remains of dozens of burned cities, unprecedented pollution traveled around the world and ascended 25 miles to the stratosphere. There the soot was trapped, immune to disruption by rain below. Skies turn from blue to gray.

Major declines in temperature in all parts of the world followed. Average rainfall declined. Growing seasons in both hemispheres immediately got shorter, as farmers from New England to China saw some crops yield much less than expected and other crops fail altogether.

Meanwhile, ozone in the atmosphere became massively depleted, and harmful ultraviolet rays at the planet’s surface increased, further injuring plants, causing greater incidence of human illness such as skin cancer, and playing havoc with the biosphere in countless ways.

The effects would last years. The World Famine of 2015-2025 ultimately was considered the worst catastrophe in mankind’s history – a tragedy affecting billions who had no connection whatsoever to the war that had been its cause. The grime high in the atmosphere lingered for years, absorbing sunlight necessary for plants, animals and people to survive and thrive — and serving to remind an appalled world, every day, of the dark potential of its nuclear technology.


The above scenario is hypothetical. What’s real, already, is the work of scientists over the past few years who have reinvestigated and revised the theories of nuclear winter that captured world attention in the 1980s. Most Americans probably haven’t thought about nuclear winter since that era, when an all-out war between the U.S. and Soviet Union looked plausible. Back then, everyone from ordinary citizens to journalists to world leaders joined the discussion about how the use of nuclear arms could imperil world ecology and, in the worst case, cause the extinction of all species.

Alan Robock, now a senior professor in environmental science at Rutgers University, was  a young scientist studying nuclear winter at that time. Today, the 63-year-old researcher is warning anyone who will listen that although the Cold War ended in the early 1990s, and the risk of a Third World War now appears to be reduced, the danger of nuclear winter persists.

Robock and a few colleagues have been using cutting-edge computer models to try to foretell the climatic consequences of nuclear explosions in an era when a “local” exchange of nuclear weapons – say, between India and Pakistan – appears more probable than a general world war.

Scientists such as Robock are asking if we can safely stop viewing nuclear weapons as an ominous threat to the world environment, merely because the arsenals of emerging nuclear powers are relatively small. Robock says absolutely not. To him, the latest ecological predictions are just as chilling as they were three decades ago. They point to prolonged, major climate damage affecting many regions on Earth, with widespread deaths from hunger in many countries. This appears true even if the usage of a “small” number of nuclear weapons was the triggering event.

NAPF spoke with Robock about his new research, and why he thinks his findings are just as urgent as the well-known nuclear winter studies of the 1980s. He also discusses his frustration that his efforts to stir the interest of government officials, and even fellow scientists, often have been met with what appears to be apathy. The following is an edited version of the conversation.

KAZEL: Dr. Robock, if you were speaking to a group of Americans who remember scientists’ warnings about nuclear winter back in the 1980s, what would you tell them about your more recent theories and how they’re relevant to today’s world?

ROBOCK: Thirty years ago, we discovered that a nuclear war between the United States and the Soviet Union could produce a nuclear winter with temperatures plummeting below freezing during the summertime, destroying agriculture around the world and producing a global famine. The indirect effects of nuclear war would be much greater than the direct effects, as horrible as they would be.

This helped to end the nuclear arms race. Mikhail Gorbachev has been quoted in multiple interviews saying he knew about the work on nuclear winter, which was being done jointly by American and Russian scientists. That was a strong message to him to end the arms race.

But that was 30 years ago. Now we’re asking two questions. One, even though the arms race is over and the number of weapons is coming down, could we still produce a nuclear winter with the current arsenals? And the answer to that is yes. Even after the New START agreement is implemented in 2017, there will still be enough nuclear weapons in the American and Russian arsenals to produce a full nuclear winter with temperatures below freezing in the summer and global famine. Most people think that the problem has been solved, but it has not.

The second question is, what would be the consequences of nuclear war between some new nuclear powers, such as India and Pakistan? Imagine…a nuclear war ensues between India and Pakistan, each of them using only 50 Hiroshima-size nuclear weapons. Their weapons might be bigger than that, but we know that’s the simplest to build. So we did a scenario by which each side used 50 Hiroshima-sized weapons. This will be much less than 1 percent of the global nuclear arsenal, and less than half of each of their arsenals.

It would be horrible. Twenty million people would die. As horrible as that would be, it would produce about 5 million tons of smoke, which would go up in the atmosphere, last for more than a decade, and cause cooling at the Earth’s surface… It would be the coldest temperatures ever experienced in recorded history – temperatures colder than the “Little Ice Age” a couple of hundred years ago, in which there was famine around the world.

This would cause devastation in the world food market. People would stop trading. There would be a famine and we estimate up to a billion people might die.

So, we’re in a terrible situation. People don’t realize that the use of nuclear weapons is still the greatest danger that the planet faces. And we have to solve this problem so that we can have the luxury of worrying about global warming – which is also a problem.

KAZEL: Why have you tended the emphasize the example of India and Pakistan as a possible place where a nuclear war might break out, rather than other areas of the world?

ROBOCK: There are nine nuclear nations now – the current members of the [U.N.] Security Council – the first five to get nuclear weapons, the U.S., Russian, China, France and England. Then there’s four more. There’s Israel, who doesn’t admit [possessing nuclear weapons], India, Pakistan and North Korea. People think, “Oh, that’s on the other side of the world. We don’t have to worry about it. They only have a few weapons. We can forget about it.” But it’s not true.

We wanted to emphasize the danger of even a small number of weapons because nuclear proliferation is still a big problem. There are other countries that want to have them.

There are 40 countries it the world that have highly enriched uranium or plutonium and could make nuclear weapons, if they wanted to. Everybody knows how to make them. Why have they chosen notto? How can we keep them [from choosing otherwise]?  Why doesn’t Japan or Germany or Belgium or Brazil or Argentina have nuclear weapons? They could if they wanted to.

We wanted to emphasize that it’s much more dangerous to have them than it is to not have them.

People still thinks it’s “mutually assured destruction” – if Country A attacks Country B, Country B will retaliate, and that’s why we don’t attack them. But it turns out it would be suicide to use nuclear weapons. If you attacked a country, and produced all these fires and smoke, it would come back to haunt you. It would affect your agricultural production.

KAZEL: Do you see much interest today among researchers around the world in nuclear winter – for example, in Russia and China, or, in particular, India and Pakistan, since this is data that’s especially relevant to them?

ROBOCK: Unfortunately no, we don’t. We write journal articles, we give talks at conferences. I just gave two talks at a conference in Europe a couple of weeks ago. Colleagues in Switzerland have recently completed a similar climate-model study…The Swiss government has given us a small amount of funding to do this work. But we would like to identify colleagues in Russia to this, and we don’t see any interest.

I talked to a Pakistani colleague at Princeton and he said, “You know, they’re really proud of this accomplishment, of being able to make nuclear weapons. If you started doing research into this [in Pakistan] to show that they can’t be used [because of environmental dangers], you would be a pariah. People would criticize you as being unpatriotic.”

Everyone who hears [my findings] gets kind of shocked by the results. Again, it’s kind of an emotional reaction and they don’t really want to hear it. But I’ve not gotten any pushback in terms of the science. Nobody’s been able to find a flaw in our science.

KAZEL: I noticed in one of your papers you expressed impatience with Global Zero because they haven’t put a spotlight on environmental dangers when they’ve campaigned against nuclear weapons. Do you think antinuclear groups have a responsibility to spread the word about nuclear winter now?

ROBOCK: Absolutely. That was [an impetus] to the end of the arms race. The first results were quite controversial. Carl Sagan was going around talking about it a lot and there was a lot of debate about it. That made people look again at the direct effects of nuclear weapons and how horrible the direct effects would be.

People had been ignoring it, and Russia and the U.S. had just been building more and more weapons. This discussion really shocked people into realizing how crazy the arms race was.

You know, this is an easier problem to solve than global warming. The solution to global warming is to stop putting carbon dioxide into the atmosphere, and that threatens a tremendous economic base of the fossil fuel companies and the energy infrastructure of the planet. It’s a tough struggle, and it’s slow. But nuclear weapons, there’s only a few thousand of them around the world. It’s a small part of the world economy. So this can change much more easily than solving the global warming problem.

Obama has said he wants to get rid of all nuclear weapons. He is trying to reduce our arsenal, but he could reduce our arsenal unilaterally without waiting for the Russians – and make us safer. Of course, you’ve got to educate people about what nuclear weapons really are in order for them to understand this.

My senator, Robert Menendez [D-New Jersey], is now the chairman of the Senate Foreign Relations Committee. I’m going down to Washington next month to try to do some lobbying and try to talk him into having a hearing about this.

KAZEL: How active should the scientists of today be in prescribing policy changes? In 2007, you [and a co-author] called for de-alerting of nuclear missiles, elimination of tactical nuclear weapons, ratification of the Comprehensive Nuclear-Test-Ban Treaty, and phasing out the use of highly enriched uranium. You’ve also said that U.S. and Russian arms reductions have been insufficient and that we could go down to a basic deterrence force of a few hundred nuclear weapons. Are you more willing now to recommend specific policies rather than just supply data to the government and the military?

ROBOCK: As far as specific policy recommendations, I’m not an expert. I’m an expert in climate. I remember in the 1980s, I was talking to another scientist about this, and he said, our job is just to provide the information and data and let the policymakers decide on the policy. I thought about that and I said, you know, the policymakers spend their careers deciding how to target nuclear weapons, how to use them, how to threaten with them. If they actually accepted our science, they would be out of a job.

The clear policy implication [of our research] is that you can’t use nuclear weapons, you have to get rid of them. If they accepted that, they’d have to find another line of work. So how can we expect them to change the policy when they have a self-interest in continuing the policy? That’s why I think it’s important for scientists to speak out.

It’s frustrating because we’re trying to get some more money to support the research. There are a lot of details that still need to be understood. We thought maybe the Department of Defense, which has the nuclear weapons and might use them, or the Department of Energy, which makes the nuclear weapons, or the Department of Homeland Security…might want to fund such studies. In every case, the program managers say, “It’s not my job. It’s somebody else’s job to look at that problem.”

Obama understands these issues and wants to do the right thing, but he needs somebody to push him. He needs a movement. He needs a lot of people to be concerned about it. People think that [the nuclear weapons] problem has faded away and there are more important concerns in their lives. They don’t feel threatened like they did in the past.

KAZEL: Apparently there is a common misconception that nuclear winter theories have been, at some point in the past, discredited or overstated. You’ve written about this.

ROBOCK: As Bob Dylan says, “How does it feel?” It feels better to believe it’s not going to be winter, even though it’s wrong. Because the arms race is over, because nobody talks about it anymore, people think the problem has disappeared.

We had this new modern-climate model, with which we did the India-Pakistan case with. We said, let’s go back and see, is it really nuclear winter? People said maybe it wouldn’t be nuclear winter, maybe it would be nuclear “fall.” We found the smoke would stay [in the upper atmosphere] for many years. Nobody knew that before. We found that indeed it would get below freezing in the summertime.

We [also] repeated the simulations we did 30 years ago. Those used a third of the nuclear arsenals on the U.S. and Russian side and produced 150 million tons of smoke. So we said, how much smoke would only 4,000 weapons produce – 2,000 on each side? And we could still get 150 million tons of smoke, the same as you’d get with the much larger arsenals of the past. You’d still produce nuclear winter. So it’s still way too many weapons.

KAZEL: In trying to demonstrate the gravity of nuclear winter, how do you convey to the public that this is potentially catastrophic? For instance, after a regional nuclear exchange, you predict average cooling would decrease two to three degrees Fahrenheit for several years. Some crops would have their growing season shortened by a couple of weeks. Those numbers may not seem dramatic to a non-scientist.

ROBOCK: We found a 10 to 20 percent reduction in the corn and soybean crop in the United States for years [following an India-Pakistan nuclear war]. We found the same thing for rice production in China for years. That brings rice production in China down to what it was when there were 300 million fewer Chinese people.

Everyone wouldn’t instantly die of starvation, but the food supplies in grain-growing regions would shrink around the world by 20 percent for a decade. That would put a huge strain on the global food trade.

Ira Helfand [co-president of the International Physicians for the Prevention of Nuclear War] wrote an article saying there might be a billion people at risk of starvation because they’re now living marginal existences. They depend on imported food. There would be nobody to come in to help them. There would be no stores of food.

KAZEL: In looking back at the media attention paid to nuclear winter in the 1980s, a huge spotlight was placed on Carl Sagan. He first warned about it in an article in Parademagazine. He was on “The Tonight Show” dozens of times and testified before committees of Congress. He was called “the people’s scientist.” Do you think the strong interest in nuclear winter at that time was an anomaly because he was so charismatic and well known, whereas today there’s no scientist like that who can stir up interest?

ROBOCK: Yes. We’ve thought about and we agree with that. We thought to get [astrophysicist] Neil deGrasse Tyson interested. He’s going to be doing a new version of the “Cosmos” show with Carl’s widow, [writer-producer] Ann Druyan. He’s the only scientist I know who even comes close to Carl.

We also tried to get Al Gore interested, because he’s got a global audience when he talks about climate. But he wasn’t interested.

So yes, we need somebody like that to give the message. We’re trying to get a Hollywood screenplay written, and do a movie about this. I think using popular culture would get a lot of people’s attention. We haven’t gotten there yet.

KAZEL: That’s interesting. Could it possibly take a blockbuster movie, like [the 1980s nuclear-war TV special] “The Day After,” to shock people into caring again?

ROBOCK: Yes, absolutely. We met a guy who’s a scientist but also writes screenplays. He’s working on it for us. We’ll see how that goes.

KAZEL: In a previous interview, you criticized the mainstream media for how it covers science. You said the media spread errors, that general-assignment reporters are allowed to write about science even though they lack the knowledge for it, and that coverage of science is often sensational. You also said scientists should stop relying on the media and find their own ways to reach the public.

ROBOCK: Sagan didn’t rely on reporters. He had his own TV show, “Cosmos.” As you say, he went on “The Tonight Show” and talked directly to the audience, without reporters involved. He wrote a book [in 1990, The Path Where No Man Thought: Nuclear Winter and the End of the Arms Race, with UCLA atmospheric scientist Richard Turco]. He wrote articles.

But the people don’t want to hear this. So you need somebody like Carl. It would be great if we had somebody like him around to give this message.

Robert Kazel is a Chicago-based freelance writer and was a participant in the 2012 NAPF Peace Leadership Workshop.