Angry people are no fun, and we tend to think of aggression and rage as personality traits that place individuals on the fringe of society. However, a new paper published in Science and summarized in the NY Times suggests that hostility and anger may be more environmentally influenced than we think….so much so, in fact, that extremes in climate cause marked increases in conflict and violent behaviors.
In a paper entitled “Quantifying the Influence of Climate on Human Conflict,” authors Solomon Hsiang, Marshall Burke, and Edward Miguel present data from 60 rigorous quantitative studies on the incidence of conflict in areas of study as diverse as archaeology, criminology, economics, political science and psychology. The link between extremes in either heat or rainfall and conflict is compelling. For example, as authors note in the Times article, “for each one standard deviation change in climate toward warmer temperatures or more extreme rainfall, the median effect was a 14 percent increase in conflict between groups, and a 4 percent increase in conflict between individuals.”
Documented aggressive behaviors that are influenced by climate (specifically, temperature change) range from merely irritating (horn-honking while driving and violence between players during a sporting event) to more serious (the use of force during police training as well as rape and assault). The graphs above demonstrate the trend for violent behaviors in the U.S. to escalate as temperatures increase just a few degrees above the norm. Authors also conclude in their journal article that “the association between climatic events and human conflict is general in the sense that it has been observed almost everywhere: across types of conflict, across human history, across regions of the world, across income groups, across the various durations of climatic changes, and across all spatial scales.” In other words, this relationship is fairly ubiquitous. The likelihood of an aggressive encounter between two apartment residents and a society-ending civil war can be equally exacerbated by a heat wave.
Authors attribute the relationship between increasing climate extremes and conflict to two factors. The first is aggression, which is aggravated by an uncomfortable environment. If you’ve ever been to New York City on a hot summer day– riding in a subway car without air conditioning– then you’ve experienced this particular combination of mood-altering factors. Moreover, scarcity of resources , which is exacerbated by any disruption in normal temperatures and rainfall, can contribute to competition and hostility.
This article caught my eye because we typically view conflict, violent events, and aggressive behaviors as being inherent in the individual or society. For example, a murder in downtown Hartford may be attributable to individual or community characteristics such as mental illness, drug use, or neighborhood safety. The influence of weather makes the outcomes of anger and hostility far less controllable, which is somewhat unnerving. With the trend in global warming becoming fact rather than prediction, can we imagine a future in which winter ski lessons are replaced by anger management classes?