The partners of nuclear war have always talked in terms of survivors. Building bomb shelters or moving to the Southern Hemisphere were considered safe hedges if international relations really got tense.
But new scientific research on the long-term atmospheric and ecological effects of nuclear war indicate that imagining safety in these strategies is a delusion.
Those not killed immediately by nuclear blasts would face a dark, prolonged “nuclear winter” of subfreezing temperatures, shortages of food and water, high radiation doses spread over the Northern Hemisphere, unprecedented pollution of the air, waterways, and oceans, and severe climatic changes lasting for several years, concluded scientists at a conference called “the World After Nuclear War” held in Washington, D.C., in November.
“Nuclear war has a set of previously unanticipated but extremely dire consequences. No longer can it be said that its effects are restricted to the combative nations,” Dr. Carl Sagan of Cornell University said. “The extinction of the human species would be a real possibility.”
“If there is anything like a global full-scale nuclear war you can kiss the Northern Hemisphere good-bye, and the effects would be catastrophic in the Southern hemisphere as well,” Paul Ehrlich of Stanford University added.
Together, Sagan and Ehrlich presented the results of several years’ research by more than 100 scientists at the conference.
In a 5,000 megaton “average” war, clouds of thick smoke from burning cities would enter the lower atmosphere and cast a pall of darkness over most of the Northern Hemisphere, later spreading to the Southern Hemisphere as well. Sunlight would be reduced drastically and the average global temperature would drop about 13 to 22 degrees Celsius in the first few weeks, rising gradually as the soot and dust settled, but remaining colder than normal for months and possibly years.
Disruption of photosynthesis in plants and the freezing of water supplies would devastate biological systems. Crops would not grow, animals would die, and many other synergistic effects would reverberate through the food chains. For example, marine phytoplankton would succumb to the lack of light, and tropical rain forests would be particularly susceptible to subfreezing temperatures. Most of the Earth’s plant and animal species would become extinct.
Even a ‘small” exchange of 100 megatons on urban and industrial targets would create enough smoke to trigger this climatic catastrophe. Additionally, radiation doses in areas remote from the targets would be 10 times higher than previously calculated, according to the new studies, and toxic fumes from burning synthetics would ravage many areas.
The picture is not much rosier if only military targets were hit in a 3,000 megaton “counterforce exchange.” Dust from high-yield explosions would enter the upper atmosphere and lower average surface temperatures by 6 to 8 degrees Celsius, again by blocking sunlight. If the light did return, it would have a dangerously high proportion of ultraviolet light because the protective layer of ozone enveloping the Earth would have been depleted. If this occurred, spending a few minutes outdoors would result in severe, life-threatening burns.
Immediately following the conference, Sagan and Ehrlich discussed their results with top Soviet scientists in a historic satellite television dialogue. “Perhaps these findings will give a new impulse in the direction of nuclear disarmament,” Eugeny Velikov, vice president of the U.S.S.R. Academy of Sciences, said. “Nuclear devices are not and cannot be weapons of war, nor can they be instruments of politics, they can only be a tool to suicide.”