Nuclear Winter: The Evidence and the Risks

nuclear-winterThis book by Owen Greene, Ian Percival, and Irene Ridge reminded me of Carl Sagan’s public campaign to frighten people about nuclear weapons while I wondered why what happened after a nuclear holocaust would be more frightening than the holocaust itself. I thought I should educate myself about what frightened people more than the direct effects of a nuclear detonation. The book mentions that the Royal Swedish Academy of Sciences published a study in 1982 that the smoke from nuclear explosions could “…blot out nearly all the sunlight from half of Earth for weeks on end. The key factor that scientists had neglected for over thirty years was smoke!” The warning prompted five American scientists; Turco, Toon, Ackerman, Pollack, and Sagan (revered in Nuclear Winter circles as TTAPS) to calculate that “…summer could be turned into winter…” Nuclear explosions would ignite fires of everything combustible in and around cities. The smoke would combine with the ejected dust to create a long list of effects. Harvests would be reduced for two years or more, countless plants and animals would become extinct, there would be deaths from collapse of medical services, famine, and epidemics. “Human suffering would be world-wide and on a scale almost beyond comprehension.

The book presents a list of nuclear weapons stockpiles as of 1985 (predating India and China). The overall total was estimated at 49,600 with a total yield of approximately 15,000 megatons. For those who often question why there were so many weapons, there is a listing of “Targeting Categories” from the U.S. Department of Defense dated March, 1980. The listing which was said to be “only illustrative,” includes: Soviet Nuclear Forces (more than 2,000 targets), Military and Political Leadership (about 3,000), Conventional Military Forces (about 15,000),Economic and Industrial Targets (about 15,000)

Soviet priorities were said to “…be similar.”

A scenario is given that describes how nuclear war could begin. That scenario results in 18,000 warheads with a combined yield of 6,000 megatons being detonated, mostly in the Northern Hemisphere. Most of the remaining warheads are assumed to have been destroyed by enemy attacks.

There is a discussion of the more immediate effects of the holocaust. Between one-quarter and one-third of the energy of a nuclear explosion is released as heat. The area destroyed by fire depends on the height and yield of the weapons. The fireball of an airburst “…varies between 55 and 250 square miles on a reasonably clear day.” The area for a ground burst is listed between 40 and 130 square miles.

There are more details to describe the holocaust. “For every megaton exploded, between 200,000 and 500,000 tonnes of dust would be carried into the atmosphere.” The large amount of smoke key to the nuclear winter theory is also explained in detail. Large amounts of carbon monoxide will be produced, which will likely kill many people in shelters. There also will be oxides of nitrogen produced along with other potentially toxic gases. However, the main focus of the book is the impact on temperatures. The smoke would block a significant amount of energy from the sun, and the effect would be that a nuclear exchange in July would result in January-like temperatures. “A 500 megaton war would…have a good chance of producing a similar climatic impact to one of the larger historical eruptions like Tambora in Indonesia in 1815. This is thought to have caused an average temperature drop of about one degree Centigrade in the Northern Hemisphere several months after the eruption. Yet 1816 was known as the year without a summer: harvests failed over large areas and six inches of snow fell in New England, USA, in June. The dangers of fallout are discussed, but not as extensively.

The book details after effects from the impact of reduced sunlight on photosynthesis needed for plant growth, although many plants would probably die from the colder temperatures. Ecosystems could recover in some form from the effects of a nuclear war, but how long would it take and what would recover. I don’t think I was as impressed as I should have been that it is likely insect pests would be “…unregulated by the usual factors.”

My short summary of the result of a nuclear Armageddon is that people not killed in the original exchange probably won’t consider themselves fortunate. The radiation will sicken many who will die from the direct effects or develop disease. The ones that survive would have to deal with where and how to find food in a devastated land. Those who have food supplies undoubtedly would also need weapons to protect what they have from those who don’t. By many accounts humankind would go extinct.

On flaw I found with the book is that it infers the risk of global cooling from nuclear war wasn’t realized early in the development of the weapons. Major N. M. Lulejian of the U.S. Air Force published a previously Secret report titled “Effect of Superweapons Upon the Climate of the World” in 1952. The declassified report predicted the results of the “Ivy Mike” thermonuclear test detonation that left a crater where Elugelab Island had been. One conclusion of his study was that “…it may be possible that a general cooling of the climate…is within the reach of man.”


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