Throughout the 1960s, a seasonal pattern of racial riots developed across urban America, leading observers to hypothesize about an association between summer heat and urban unrest. The Kerner Commission, tasked by President Lyndon Johnson with investigating the causes of the more than 150 riots that broke out in 1967, lay the blame on a toxic combination of poverty and racial politics. However, the Commission also noted that anger in urban America was being stoked by the uncomfortable heat of summer.

One might be tempted to leave the latter argument in the past, a remnant of long since dismissed environmental determinism and a particularly ugly period in America’s racial history. However, rising mercury levels are well known to lead to a myriad of undesirable behaviors, ranging from sporting event violence to petty crime, and recent climate change research suggests that many more of us are now or will soon experience warmer weather, either as a level increase or in conjunction with more frequent weather extremes.

So the question must be asked, is our growing globe of cities and rapidly changing climate a ticking time bomb of social unrest? Are we all at risk of becoming hotheads?

In a recent article in the Journal of Peace Research, I attempted to answer this question by examining the relationship between temperature and the occurrence of urban unrest in Asia and Africa. Although widespread violence was fortunately avoided after Ferguson, my analysis supports, with some qualifications, previous research indicating that urban unrest increases during hot weather.

It is not heat that triggers these incidences. There are economic, political, and cultural conflicts that bring people into the streets. The Arab Spring, communal riots in India and Nigeria, and communist revolutions of the mid-20th century attest to the many motivations of participants. But the available data shows there is a relationship: urban unrest in Asian and African cities is most common and occurs with greater frequency and more violence during relatively warmer months.

For the complete article, please see New Security Beat.