Nuclear winter

From dKosopedia

A nuclear winter is the anticipated result of an exchange of nuclear weapons between two (or more) nations. The reasoning is that such attacks over urban areas would produce immense amounts of smoke, ash, etc. that would rise to very high altitudes due to the updraft from the heat of the nuclear weapon and the head of the resultant burning buildings. Once at high altitude, these fire products would spread around the world forming a curtain that would reduce the amount of sunlight that could reach the ground. Just as has happened with major volcano eruptions, the earth could experience a general cooling. The more the nuclear destruction, the heavier the high altitude smoke screen, the longer it would take to disperse, and the colder the earth would become. Winters would become colder, resulting in greater needs for animal feed, fuel for heating, etc. Growing seasons would be shortened, plants would grow less successfully under reduced sunlight, plants would not enjoy the temperatures that their evolution has suited them to, and in general agriculture could easily fall below the minimum level needed to feed the people of the earth. Furthermore, transportation of such food resources as were available could be severely hampered in more remote northern regions.

Following upon a time of severe devastation of population centers, industrial facilities, etc., a diminished and demoralized population would be forced to deal with an unprecedented threat. Competition for diminished resourced (particularly of food and fuel) could spark secondary conflicts.

Current economic conditions in the world, particularly in the United States, may encourage members of the oligarchy to believe that their wealth would protect them, feed them, and keep them warm, thus encouraging them toward adventurism. At the same time, the great majority of people impacted by such an outcome of war would have reduced resources available to meet the challenge of a radically deteriorating environment. Different scenarios might play out, ranging from a mass revolt against the upper classes, religious fanaticism directed against supposed enemies, to mass die-offs of those enjoying fewer resources. The single advantage for the long haul might be that a high percentage of the world's population would die off due to cold and starvation, and another large group would die prematurely as the result of radioactive fall-out from the nuclear exchanges.