El Niño and Wars

El Niño events increase the tendency to go to war. Compare with other work on the rainfall theory of democracy, and the tendency of centralized states to first emerge in marginal rainfall environments.


Ur, in the "Fertile" Crescent. It was a little greener 10,000 years ago, but certainly even then there were better places to start civilization. The relationship between city-states and soil fertility is inverted-U-shaped.