As Londoners try to reclaim some sense of stability in the aftermath of last week's riots, commentators are continuing to debate the causes of 4 days of violence that resulted in 5 deaths and over 1,100 arrests and that left the capital charred and shell-shocked. Most have focused on recent events - the News of the World phone hacking scandal or the death of 29-year-old Tottenham resident Mark Duggan, who was shot by police offers last Thursday - as possible triggers. Some believe that the riots were protests of indigent youth enraged by the extravagances of a city that has been more concerned with celebrating the Royal Wedding and preparing for the 2012 Olympic Games than addressing the economic hardships of its citizenry.
London would not be the only city in which the eve of the Olympic Games coincided with a violent confrontation between youths and the state. In La Noche de Tlateloco, Elena Poniatowska gives a vivid account of the massacre of student demonstrators in Mexico City's Plaza de las Tres Culturas tens days before the opening of the 1968 Olympic Games. Youth protests over constitutional reform in South Korea also turned violent months before Seoul was to host the 1988 Olympic Games.
Although this would seem to suggest a causal trend, researchers who have been studying the causes of state political instability long before the riots in London would say that the critical common factor is the density of youths. In 1990, demographers Gary Fuller and Forrest R. Pitts proposed that a nation's extent of political unrest, i.e. its vulnerability to riot, war or regime change, is directly associated with the percentage of 15-24 year olds in its population. They argue that communities with more than 20% of individuals in this age group run the greatest risk of more frequent and more intense political instability. They describe the phenomena as the "youth bulge theory", where the "bulge" refers to the fattening of the population pyramid just before the base of the youngest age groups. Coincidentally, the authors introduced the hypothesis in a paper about uprisings in South Korea, and they note that the percentage of 15-24 year olds in Seoul in 1980, 1985, and 1990 was 24.4, 21.3, and 20.0%.
Could youth bulges explain why riots occur? Map 1 plots data gathered by the Political Instability Task Force on worldwide atrocities between the years 1995-2008. An atrocity is defined by the dataset authors as an "implicitly or explicitly political, direct, and deliberate violent action resulting in the death of noncombatant civilians." Map 1 shows that the total atrocities classified as riot or pogrom have been most frequent in African nations, Indonesia, and India. Map 2, which reports the total deaths associated with these events, shows that the intensity of the atrocities has been greatest in these same areas.
As a graphical ecological study, we can test the youth bulge theory by seeing if the populations in these areas predominately consist of young adults. Map 3 shows the current median age of the countries of the world. More than 50% of the individuals in most African regions fall in Fuller and Potts' bulge. Countries in Latin America and Southeast Asia, where violent uprisings have been occurred in the recent past, also have populations whose citizens are mostly under the age of 30 years.
And for London? The 2001 census shows a bulge in the 14-30 year old age groups, with 14-25 year-olds making up 13% of the male population. This is shy of the 20% threshold for a bulge but this data is also ten years old. The Office of National Statistics will be releasing the 2011 census data on August 28th.