Re-Thinking Nuclear War
The hydrogen bomb age had a profound effect on the thoughts of nuclear war in the popular and military mind. With only fission bombs, nuclear war could be considered something that could easily be "limited." Dropped by planes and only able to destroy the most built-up areas of major cities, it was possible to consider fission bombs simply a technological extension of previous wartime bombing (such as the extensive firebombing which took place against Japan and Germany during World War II), and claims that such weapons could lead to worldwide death or harm were easily brushed aside as grave exaggeration. Even decades before the development of fission weapons, there had been speculation about the possibility of human beings ending all life on the planet by either accident or purposeful maliciousness, but technology had never allowed for such a capacity. The far greater power of hydrogen bombs made this seem ever closer.
The "Castle Bravo" incident itself raised a number of questions about the survivability of a nuclear war. Government scientists in both the U.S. and the USSR had insisted that fusion weapons, unlike fission weapons, were "cleaner" as fusion reactions did not result in the dangerously radioactive by-products as did fission reactions. While technically true, this hid a more gruesome point: the last stage of a multi-staged hydrogen bomb often used the neutrons produced by the fusion reactions to induce fissioning in a jacket of natural uranium, and provided around half of the yield of the device itself. This fission stage made fusion weapons considerably more "dirty" than they were made out to be, a fact made evident by the towering cloud of deadly fallout that followed the "Bravo" test. When the Soviet Union tested its first megaton device in 1955, the possibility of a limited nuclear war seemed even more remote in the public and political mind: even if a city or country was not the direct target of a nuclear attack, the clouds of fallout and harmful fission products would disperse along with normal weather patterns and embed themselves in the soil and water of non-targeted areas of the planet as well. Speculation began to look towards what would happen as the fallout and dust created by a full-scale nuclear exchange affected the world as a whole, rather than just the cities and countries that had been directly involved. In this way, the fate of the world was now tied to the fate of the bomb-wielding superpowers.