I stifled the urge to make a smart crack. “So what are your plans now?” I asked.
“I got a call from the publisher. News travels fast—they've cancelled the rest of the book signing tour. And I don't suppose I'll be writing up this sordid tale since the papers will be full of it. I might just see if Professor Janeway could use another postdoc."
I sipped at the rich, black coffee. “You're putting the Voynich behind you?"
“No,” she said. “When you look into a mystery that deep, it doesn't let you go until it's solved. I'll be working on that until I crack it, or until I'm too old to care anymore."
“So you still think it might not be a red herring dreamed up by some long-dead con artist?"
“Wrong metaphor, Mr. Sanko.” Pamela smiled coyly around her raised cup. “You want to believe it's a meaningless hoax—that's pink salmon. The Voynich is saying there are more things in Heaven and Earth than are dreamt of in your philosophy."
“That's Hamlet."
She laughed. “No, Mr. Sanko,” she said, “that's white salmon in the can."
Copyright (c) 2008 Thomas R. Dulski
[Back to Table of Contents]
* * *
Science Fact: NUCLEAR AUTUMN: THE GLOBAL CONSEQUENCES OF A “SMALL” NUCLEAR WAR
by Richard A. Lovett
It started with a pair of nuclear suitcase bombs, exploding simultaneously in Bangalore and Islamabad. Nobody knew who was responsible, but India blamed Pakistan and Pakistan blamed India. For a few horrifying hours, the two countries hurled nuclear weapons at each other, until, by the time cooler heads finally prevailed, dozens of bombs had been detonated by each side.
They weren't large as such weapons go—their total explosive power was only 0.03 percent of the world's entire arsenal—but they were big enough. The first day's casualties rivaled those from all of World War II and the fallout dwarfed that from Chernobyl and Hiroshima. But worse was yet to come. Within weeks, the global climate shifted. Europe, Russia, North America, Australia, Chile, Argentina all saw massive crop failures—not just the first year, but the next, and the one after that as well. It wasn't the end of the world, but the famine, panic, and ensuing chaos launched a global dark age: all from a war between regional rivals whose nuclear stockpiles were small by superpower standards.
* * * *
If that scenario sounds familiar, it's because something similar was proposed (and hotly debated) in 1983 by a team of scientists spearheaded by the late Carl Sagan. That team, whose initials led them to become known as TTAPS (for Turco, Toon, Ackerman, Pollack, and Sagan), dubbed their theory “nuclear winter” and posited that smoke from fires ignited in a nuclear war between the U.S. and the Soviet Union would darken the sun and plunge temperatures below freezing across much of the globe.
Unfortunately, the climate models of the era left a lot of margin of error, and while Sagan's team stuck to their general findings, they would later admit that they'd made some mistakes in the details. In particular, in the aftermath of the first Gulf War, Carl Sagan predicted that smoke from Kuwaiti oil well fires would have global consequences: something that didn't happen.
Sagan's team, however, was modeling an all-out nuclear war between two superpowers, in which hundreds or even thousands of enormous bombs were used by each side. (In one scenario, the total explosive power was 5,000 megatons.) With the end of the Cold War, the risk of such a holocaust receded, and so, it seemed, did the risk of nuclear winter.
But now, a new team, led by two members of the original TAPPS team, believe that this relief was premature.
In a series of papers presented at a 2006 meeting of the American Geophysical Union, these scientists wondered what would happen in a smaller nuclear exchange between any of the world's emerging nuclear powers. Nobody knows how such a war would play out, but if you're a small nuclear power with a serious grudge against a neighbor, you're likely to use your arsenal primarily against cities—especially if you have only a limited number of relatively small bombs ("small” defined as approximately the power of those dropped on Hiroshima and Nagasaki).
It turns out that the global effects from even a limited exchange of such bombs might not be vastly different from those of the monstrous H-bombs the U.S. and U.S.S.R. once aimed at each other.
Partly that's because we have better atmospheric models today than the TTAPS team did twenty years ago, allowing us to examine in more detail the way large smoke plumes behave in the atmosphere. But it also turns out that you can set an enormous fire with a relatively small bomb. When it comes to destroying a city, says one of the original TAPPS members, Richard Turco,[1] “a megaton-scale weapon is simply overkill."
[Footnote 1: Turco is an atmospheric scientist at the University of California, Los Angeles.]
Another factor is the incredible population density of many developing-world cities. “We're growing megacities all over the world,” says another member of the original TTAPS crew, Owen Toon, an atmospheric scientist at the University of Colorado at Boulder. “Tehran has 10 million people."
Turco and Toon estimate that an exchange of fifty Hiroshima-scale bombs apiece by Pakistan and India could easily kill twenty million people—and that's not counting the effects of fallout. Even a single bomb hitting a country such as Argentina, Brazil, or Egypt could inflict a hundred times as many casualties as any of these countries experienced in all the wars they've ever fought, Toon adds.
It also turns out that smaller bombs are nearly as effective at setting fires as their megaton cousins. One Hiroshima-sized airburst (fifteen kilotons) would ignite everything in a five-square-mile region, says Turco. And that's not even taking into account the fact that the fire would presumably spread, since putting it out would be well nigh impossible.
Conventional explosions set fires directly, from the heat of the blast. But a nuclear explosion also produces an intense pulse of blinding light radiating in all directions. “It's like bringing a piece of the Sun close to the Earth,” says Turco. “It's that which creates these extraordinarily intense firestorms such as occurred at Hiroshima."
Any city has a lot to burn. A crowded megacity has an enormous amount of potential fuel. Turco estimates that industrialized cities have about ten tons of combustible material per resident. In the developing world, good figures are harder to obtain, but five tons per person is a good estimate, he says.
To give even an inkling of the type of fire that would be ignited, Turco turns to the blaze that roared through San Francisco in the aftermath of the 1906 earthquake. When the earthquake occurred, author and journalist Jack London was on his ranch, well to the north. He rushed to the city and watched in horror from a boat on San Francisco Bay. Even though the day was dead calm, the rising flames drew air from all sides. “East, west, north, and south, strong winds were blowing upon the doomed city,” he wrote. “The heated air rising made an enormous suck. Thus did the fire of itself build its own colossal chimney through the atmosphere. Day and night this dead calm continued, and yet, near to the flames, the wind was often half a gale, so mighty was the suck."
In essence, the fire, once started, would fan itself, gaining intensity and blasting a roaring column of smoke far into the sky.
In a modern city, more than wood would burn. Gasoline storage tanks, asphalt shingles, automobile tires, and plastics would also contribute. And all of these are extremely smoky. This was a factor in the 1980s, when the original TTAPS model was constructed. But since then, Turco says, production of plastics has doubled, worldwide. And it's not just an industrialized-world phenomenon: the developing world is rapidly catching up.
To estimate the potential amount of smoke released in a nuclear exchange, Turco's team borrowed the terminology of forest-fire fighters, calculating the “fuel loading” of the fifty most densely packed areas in several countries that might someday be nuclear targets. And while smoke (especially from burning plastics) has many constituents (including such toxics as dioxins, furans, PCBs, arsenic, lead, and benzo(a)pyrene), the
group focused only on the sooty, sunlight-blocking ones. From the fuel loading, the mix of fuels, the fraction of material likely to burn, and the amount of soot each material produces, they concluded that about 40% of the soot would come from burning wood and paper products, 15% from plastics, 15% from asphalt roofing, and 30% from petroleum and petroleum products. All told, they calculated that an exchange in which both sides used fifty Hiroshima-sized bombs would produce between one and five million tons of smoke, per country.
To put that in perspective, Georgiy Stenchikov of Rutgers University compares it to the amount of smoke produced by one of Canada's worst forest fires. Called the Chisholm Fire, it raged across central Alberta in May 2001, blackening a quarter-million acres of timber, and producing a smoke plume that spread from Hawaii to the Norwegian Arctic. It was the most dramatic forest-fire plume ever seen and towered to an elevation of seven to eight miles: high enough to reach the lower stratosphere. But it only produced only five thousand tons of smoke. To match the hypothetical 100-Hiroshima war, it would have to have burned an area larger than the state of California.
That's a vast amount of smoke—made all the more significant by the fact that it doesn't actually take all that much smoke to darken the sun significantly. “It's highly efficient stuff,” says Turco.
* * * *
Self-Lofting Plume
Another new discovery is that when this soot reaches the atmosphere, it will “self loft” to ever-higher altitudes.
That's not the case for smaller fires. Their smoke plumes will rise a few thousand feet into the sky but won't break out of the “boundary layer"—the portion of the Earth's atmosphere that is most directly affected by events at the surface. Even the Kuwait oil fires didn't get through the boundary layer, which is why their effects were limited to the Persian Gulf region.
But nuclear-spawned fires would be different. The dense, black smoke would rise in a two-step process. First, the raging firestorms would produce vast amounts of heat—more than a thousand times as much energy as was released by the bomb blasts themselves. That would drive the plume upward, through the boundary layer, where it would spread out in a dark blanket.
Beneath the smoke, temperatures would plummet. When Krakatoa erupted in Indonesia in 1883, there are reports that temperatures beneath its ash cloud dropped by as much as 14 degrees F. There would also be weird weather effects: the firebombing of Tokyo in 1945 reportedly spawned a tornado.
But the main effect is that the energy not reaching the ground wouldn't simply be reflected back into space: it would be absorbed by the black cloud. This would cause the soot to remain warm, rather than cooling and sinking back to the lower atmosphere.
In a small fire, the smoke would nevertheless disperse and start sinking around the edges. But in a big one, a cloud of sun-warmed smoke would rise ever higher until it punched though the top of the lower atmosphere, into the stratosphere. The effect would be worse in southern countries, such as India or Pakistan, where intense, low-latitude sunlight would more easily heat the smoke. The reason the Kuwait oil fires didn't do this, Turco says, is simply that impressive as they were, they were too spread out and weren't individually intense enough for the self-lofting effect to come into play.
* * * *
Deathly Pall
Once in the stratosphere, the smoke would continue to rise. It would also be caught in high-altitude winds such as the jet stream and whisked around the world. Within a month, says Alan Robock, also of Rutgers University, a thin haze would girdle the entire planet.
When Mt. Pinatubo erupted in the Philippines in 1991, it blasted enough sulfuric acid into the stratosphere to create a bright haze that not only caused spectacular sunsets, but produced a noticeable dip in global temperatures. Due to the nature of volcanic gases, the Mt. Pinatubo effect lasted only a year. But the effect of the soot would be longer lasting and several times larger, says Luke Oman, another Rutgers scientist.
Overall, he and Robock calculate that the average global temperature would dip by more than 2 degrees F and stay below normal for a decade. Rainfall would also decline, by about 10%.
Two degrees doesn't sound like much, but it is more than the cumulative effect of global warming since the dawn of industrial civilization. It's also substantially bigger than the climate change that set off the “Little Ice Age,” which lasted from the sixteenth to the nineteenth centuries and led to Hans Brinker skating the canals of Holland, glaciers advancing across Swiss farmland, and New Yorkers (on at least one occasion) walking across the ice from Manhattan to Staten Island. It would, Robock says flatly, be a global climate change unprecedented in recorded human history.
This doesn't mean it would be a full-fledged nuclear winter. Rather, the scientists are referring to it as nuclear “autumn."
Nor is there any threat of a renewed ice age, little or otherwise. What a nuclear autumn would do is wreak havoc with growing seasons, particularly in regions like Europe, Australia, or the American Midwest, where, in the heart of large continental areas, the summertime cooling effect would be unusually strong—higher than 5 degrees F in some places. As a result, Robock estimates that these countries could see their growing seasons reduced by ten to thirty days—a major effect, because farmers wouldn't have planted the right crops for the new conditions.[2] Even in the tropics, he says, the change in temperature would strain agricultural productivity.
[Footnote 2: For maps of these and other predictions, including an animated depiction of how the smoke would spread in the days, weeks, and months after an India-Pakistan exchange, see climate.envsci.rutgers.edu/nuclear.]
The Earth's ozone layer would also suffer. That's because the soot would absorb sunlight, substantially increasing the temperature of the stratosphere.
Most people think the atmosphere gets steadily colder as you go higher. But that only applies close to the surface, in the narrow band of altitudes that we inhabit or fly through on airliners. Higher up, the thin air warms substantially, until at the top of the stratosphere, fifty kilometers or so above the surface, its temperature has climbed back close to the freezing point.[3]
[Footnote 3: It gets hotter yet in the higher layers, one of which, revealingly, is called the thermosphere.]
The soot, however, would rise all the way to the top of the stratosphere, continuing to absorb sunlight. The result, says Michael J. Mills of the University of Colorado at Boulder, is that the temperature there would increase by 180 degrees F.
All of that extra heat would induce chemical reactions that would wreak havoc with the ozone layer, reducing it, Mills calculates, by a global average of 20-25% for at least 3.5 years. “What we have, basically, is a global ozone hole,” he says.[4]
[Footnote 4: The heating of the stratosphere would also increase the amount of water vapor it can contain, also altering the upper atmosphere's chemistry.]
At the mid-latitudes, including the U.S., the drop would be higher: 30-40%. At the poles, it would be 70%. The result would be a substantial increase in the amount of ultraviolet reaching the surface—important, Mills says, not only in the U.S. and Europe, but even in the tropics, because plants and animals everywhere are adapted to the levels of ultraviolet they normally receive.
* * * *
Winter Still Possible
Nor, the scientists noted, are we free of the specter of a full-fledged nuclear winter. Using today's far-better climate models, Robock reran the original nuclear winter scenario, which involved many times more nuclear firepower, but (due to the overkill effect) only about thirty times as much smoke as the hypothetical Pakistan-India war.
The effects didn't turn out to be thirty times as bad, partly because beyond a certain level, the smoke begins to block itself, so that each new soot particle has less impact. But they were bad enough.
One of the questions raised by critics of the original TTAPS study was whether it was overstating things to call it nuclear “winter.” Now, the scientists are sure that it really would be. In substantial parts
of the world, the temperature would quickly drop below freezing and stay there for more than a year, Robock said. On average, the revised model found that a nuclear exchange producing 150 million tons of smoke would initially drop the global temperature by 14 degrees F, and still be holding it down by 7 degrees F, a decade later. An exchange producing fifty million tons of smoke would have about half that effect.
“This is new,” Robock said. “The effect went on a lot longer than we thought."
* * * *
At the other end of the scale, nobody knows what would happen if a pair of regional enemies exchanged only twenty-five bombs, each, or ten, or five. A lot would depend on where the bombs were dropped. Besides, the scientists don't want to find themselves saying something on the order of: “Fifteen bombs are okay, but sixteen aren't."
What they will say is that a lot of countries have the ability to make bombs.
Right now, there are eight known nuclear powers: the U.S., Russia, Great Britain, France, China, India, Pakistan, and (apparently) North Korea. Israel is widely presumed to have nuclear weapons, and several members of the former Soviet Union once had them, but gave them back to Russia. South Africa was also once a nuclear power, but says that it subsequently dismantled its weapons.[5]
[Footnote 5: A detailed history of this can be found on the website of the Center for Nonproliferation Studies, cns.miis.edu/index.htm.]
But that's just the beginning. A total of about forty nations have the requisite materials on hand in their nuclear power plants to make from one to 10,000 bombs, Toon estimates, and some, like Japan, could produce weapons in a matter of weeks or months, if they were ever inclined to join the nuclear club. Most of Europe is on the list, but it also includes South Korea and economic rivals Brazil and Argentina. “Fifty weapons is not a challenge for a country to make,” Toon says.
“We are at a perilous crossroads, not a declining threat,” he adds. “Taken together, the current combination of nuclear proliferation, political instability, and urban demographics poses perhaps the greatest danger to society since the dawn of humanity."
Analog SFF, April 2008 Page 6
