The decline of the Soviet Union may have left many Americans feeling safer from nuclear war, but a disturbing new study argues that an attack by terrorists sponsored by a small nuclear state could be just as lethal.
Such an attack "could generate casualties comparable to those once predicted for a full-scale nuclear exchange in a superpower conflict," says the report, presented Monday during the fall meeting of the American Geophysical Union in San Francisco.
Furthermore, Americans should not think of themselves as isolated from potential small-scale, regional nuclear conflicts in such distant areas as the Middle East or Asia. The impact of such an encounter would be global, probably plunging the planet into a "nuclear winter" and blanketing wide areas of the world with radioactive fallout.
The report, which cautions that there are many uncertainties in its own conclusions, was produced by a team of scientists who have been long active in studying the consequences of nuclear war.
The study assumes that weapons used by terrorists, or smaller states, would be much smaller than those available to the superpowers, probably on the scale of those dropped on Japan during World War II. But the results would be catastrophic because the weapons would most likely be targeted at major cities.
"The current combination of nuclear proliferation, political instability, and urban demographics forms perhaps the greatest danger to the stability of society since the dawn of humanity," Brian Toon of the University of Colorado in Boulder told a press conference prior to the presentation.
The number of countries known to have nuclear weapons has grown to eight, but as many as 40 have some fissionable material and could produce bombs fairly quickly, the scientists said, basing their conclusions partly on studies by the National Academy of Sciences, the Department of Defense, and their own years-long research. Toon said Japan, for example, has enough nuclear material on hand to produce 20,000 weapons, and "most think they could do it in weeks."
Many of the conclusions are based on the consequences of two nations, each with 50 bombs, delivering their full complement of weapons on each other. That's not a hypothetical figure, they suggested, because both India and Pakistan are believed to have at least that many weapons.
So what would happen if they had at it?
About 20 million persons in that area would die, the scientists concluded. But the weapons would send up such a plume of smoke that the upper atmosphere would become opaque, blocking out so much solar radiation that temperatures around the world would plummet.
"You would have a global climate change unprecedented in human history," said Alan Robock, associated director of the Center for Environmental Prediction at Rutgers Cook College and a member of the research team. "It would instantaneously be colder than the little ice age." There would be shorter growing seasons, less rain, less sun, and starvation around the world.
Richard Turco, the founding director of the Institute of the Environment at the University of California, Los Angeles, said the results would be about 10 times worse than the historic eruption of Tambora in Indonesia in 1815, which sent killing frosts across North America. That year became known as "the year without a summer."