Alan Robock and the nuclear winter
• "Nuclear weapons are the major threat hanging over the human species today"
(Taken from CubaDebate)

• CITIES would burn for weeks and even months spreading a vast cloud of ashes that would paint the sky black. The mushroom clouds from thermonuclear explosions would raise clouds of dust and smoke to stratospheric heights where they would remain suspended for years, masking sunlight. Temperatures on Earth would drop drastically within a few weeks. For at least one or two years sunshine would be weak. After this disaster, a frozen and barren world would emerge in which 90% of world harvests would fail and the energy generation capacity would be reduced by more than half. Without the means of heating themselves, cities would turn into ice flows of cement abandoned an account of the resulting harsh famine.

It is not a parody of the Apocalypse but the world validated by scientific models if just 1% of the atomic bombs currently existing on the planet were to explode. A conflict between India and Pakistan, two countries that possess this kind of weapon would suffice to make the nightmare that researchers have called the "nuclear winter" a reality.

Alan Robock, from the Department of Environmental Sciences at Rutgers University in New Jersey, confirmed the "nuclear winter" theory together with a team of well-known U.S. and Russian researchers. It was he who presented the conclusions of his study in an impressive conference in Havana on September 14, attended by Comandante en Jefe Fidel Castro on and which was broadcast on Cuban Television’s "Roundtable" program on September 15.

"Fortunately that theory has never been tested," the scientist said to Fidel in a brief conversation at the end of the conference, "but the only guarantee that that will not occur in the future is if all nuclear weapons are destroyed. While they are there, accidents, miscalculations and crazy people who could have these weapons in their power will continue to be of concern to us."

Alan Robock first words are in the Spanish that he learned in high school 45 years ago, too long ago to give a paper in that language. The detail of language is relevant in terms of something that was to happen later, but he begins his lecture in English, accompanied by images, without using terms that are too technical, although most of the public attending his master lecture titled "The climatic consequences of a nuclear conflict," were scientists taking part in a workshop of the same name convened by the Institute of Meteorology.

The first idea that he outlines is categorical: "Warming is a serious problem, but nuclear weapons are the greatest threat currently hanging over the human species." And then he showed two images: the first, he says, "is our lovely planet." The second, what it could become after a nuclear war: smoke would cover the Earth, blocking the sun, making the surface a cold, bleak, dark plain full of dust. The whole auditorium was taken aback. Fidel opened his blue notebook. He had begun to take notes.

In a very didactic way, Robock explained that the first strokes of the nuclear winter theory correspond to a 1982 study by Paul Crutzen and John Birks, which already proposed that the massive fires that would result from a global nuclear interchange and the smoke that these would generate in the lower layers of the atmosphere would have notable effects on the climate.

Owen B. Toon and Richard P. Turco analyzed the consequences of smoke on the stratosphere and coined the expression "nuclear winter," while Soviets Vladimir Aleksandrov and Georgiy Stenchikov carried out simulation experiments on more sophisticated models in 1983. It was partly as a consequence of these studies and other related ones at the end of the 1980s that nuclear disarmament treaties were initiated between the United States and the Soviet Union. "At least that’s what Gorbachov said," the scientist noted.

The theory is simple and horrible, Robock added. "If sunlight is blocked, the Earth’s surface would cool below freezing point. Think of this: at night the sun is hidden and the temperature drops. What would happen if the sun didn’t rise at dawn? A tragedy for the planet, the consequence of which would be the loss of harvests and the threat of epidemics of famine."

This research began 25 years ago. "You might ask yourselves, why am I talking about that today? While the Cold War and the nuclear arms race associated with it has ended, the nuclear arsenals that currently exist could perfectly well produce a nuclear winter."

If there were just 100 nuclear weapons, a "nuclear winter" might not be produced, but the consequences would still be tragic from the point of view of their direct effects and the climate change would be unprecedented in human history.

In the year 2000, Robock and a group of researchers, among them Stenchikov, Toon and Turko, who had developed the theory in the 1980s, undertook a series of studies in which they took into account the planned reduction of nuclear weapons in the United States and Russia (The Strategic Arms Reduction Treaty). They compared the consequences of an exchange within the arsenal permitted in that context, with a limited exchange between minor nuclear powers like India and Pakistan.

According to this study, even the most modest atomic exchanges would be enough to produce effects of the same order of the Little Ice Age or one year without a summer. The study also suggested that the change in stratospheric temperature, even in this case, could have serious consequences on the flow of gases and considerable concrete reductions in the ozone layer. The use of the Russian and U.S. arsenal would lead to a drop in temperature comparable to or possibly more marked than that of glaciation, perhaps for one decade.

"Despite the fact that various arsenals have been reduced, a great danger still exists," and he explained with the use of slides: "This is a graph of the countries that have nuclear weapons. As you can see, the five permanent members of the UN Security Council were the first to obtain nuclear weapons, and afterward there is Israel, India. Israel helped South Africa to obtain nuclear weapons but then that country got rid of its weapons… Then other countries produced nuclear weapons. If this trend continues, the world will turn into an even more dangerous place."

How to manufacture a nuclear weapon is no secret. The only limiting factor would be not having the uranium or plutonium, the researcher affirmed. They could build another 100,000 weapons if they so wished. Why are there no nuclear weapons in the Southern Hemisphere? Why don’t other powers in the Northern Hemisphere have them? What lesson could we draw from those countries that are refusing to have nuclear weapons? he asked.

"If the purpose is to threaten someone else in order not to be attacked, how many weapons would be needed in capitals in order to threaten those potentially aggressive countries. Just one, maybe two weapons, would suffice in order to dissuade any other country," he stated. In that case, arsenals could be dramatically reduced right now.

But the reality is that today the nuclear arsenal is one third of the size of the one that existed in 1985, but the weapons have an explosive power that is 10,000 times greater than all the weapons used during World War II. "If all the weapons available today were divided among the six billion-plus inhabitants of the planet, every citizen would have the right to possess approximately 750kg of TNT. Isn’t that crazy?" Robock asked.

"Sometimes, pictures speak louder than words," he commented. "The diagram that you’re about to see represents all the nuclear weapons on the planet. The point in the middle is equivalent to the arsenal that existed during World War II, and the whole shaded part belongs to the nuclear arsenal."

What does a nuclear explosion mean? "The light is so intense that it burns everything. The expansive wave is extended. During the first nuclear war, the U.S. dropped two atom bombs on Japan. The first, on Hiroshima, with an explosive potential of 15 kilotons, which is three millionths of the current arsenal. One hundred and fifty thousand people died.

And this is a photo of Hiroshima after the attack.

"The survivors recall the fire and the smoke. Where did all the buildings and houses go? They were burnt and went up in smoke. Unfortunately, we have an example of a nuclear explosion which proves that it produces fire and destruction within a radius of hundreds of kilometers," he confirmed.

Robock gave examples of other nuclear tests that confirm his theories. "In our studies, we have reached the conclusion that if 100 15Kt bombs are dropped – which is the equivalent of less than 1% of the world’s nuclear arsenal – almost 20 million people would die instantaneously because of the direct effects. Five teragrams of smoke would be discharged into the atmosphere," he stated.

After other examples ranging from what happened in the San Francisco earthquake of May 1906, to dust storms on Mars and the meteorite which struck the Earth 65 million years ago and wiped out the dinosaurs, the scientist demonstrated that "the nuclear winter is a perfectly possible theory, due to human intervention.

"The only way of avoiding this would be to get rid of nuclear weapons," he concluded.

Following a discussion with Fidel Castro Díaz-Balart, scientific advisor to the Council of State, regarding the research models of the "nuclear winter," Fidel asked how many people around the world are aware of this information. He confirmed that it was only a few.

"They are quite simply unaware of it and it seems to me to be a sufficiently serious issue that should be known and circulated… We have to fight so that the world learns about it," said Fidel.

Robock has an explanation for the silence surrounding this theory: "Denial," he said. "It’s so horrible that people don’t want to think about it. It’s much easier to pretend that it doesn’t exist."

But Fidel is optimistic; he clings on to human values. "Our battle is to create awareness of something about which we talk so much; creating a culture." He went on, "I believe in the ability of our people and those around the world to learn…It is not impossible to create awareness over and above all that indifference and, most of all, over and above ignorance."

"We have in television and in the media instruments to help us in the battle for knowledge of these dangers," he remarked after an exchange with Cuban television journalist Gladys Rubio. "There are conventional weapons today that are even more destructive, concretely, than nuclear weapons. The problem is who will fire first and that is what we are trying to avoid. We can see the risks posed by ignorance and the possession of these weapons in this day and age. One hundred of them could wipe out human life," said the leader of the Cuban Revolution.

With Fidel’s words of optimism and adopting a more cheerful tone, the conference came to an end. "We are very grateful for what you have taught us and we are going to circulate that information," confirmed the leader of the Revolution and presented Robock with copies of his most recent books La victoria estratégica and La contraofensiva estratégica. "Professor, for your Spanish revision. It’s not propaganda," he laughed and repeated: "Practice your Spanish". To which, Robock responded, "Comandante, I don’t have any books but I’ll give you one of my articles."