Ecology of war

Many seemingly random or chaotic human activities have been found to exhibit universal statistical patterns. Among these is human conflict: the size distribution of casualties aggregated over entire wars follows an approximate power-law distribution. But do the events within individual wars share any common patterns? Neil Johnson and colleagues show that they do. Using detailed data sets from a wide range of conflicts, including Afghanistan, Iraq and Colombia, they show that insurgent wars share common patterns with each other, and also with global terrorism. They explain the size and timing of violent events in terms of ecological interactions between human groups. Their model is consistent with recent hypotheses concerning insurgency and establishes a quantitative connection between insurgent warfare, terrorism and ecology. Similarities to financial market models point to a link between violent and non-violent human behaviour.