The Heat and the Fury
New research shows that a warmer world is a more violent one
August 10, 2011 was the day the police finally regained control of London. Armoured cars lined up along Commercial Street in the East End, a military convoy waiting to sweep up Bethnal Green Road to where the housing estates still stank of burned rubber and the blackened shells of cars smouldered. The shutters of supermarkets pulled down all around the capital, the sidewalks empty and still in what should have been rush hour.
In major urban centers across England, there had been a terrifying convulsion of violence, starting on August 6. Whole rows of shops had been looted and burned by mobs that gathered out of nowhere, called to action over Blackberry Messenger. The fluidity, speed and sheer scale confounded the police response.
Driving that violence was a complex mix of economic exclusion, poverty, selfish opportunism and socialised greed. Among the real and perceived grievances amongst the youth in austerity-era London, Birmingham and Manchester, there was a simple avaricious instinct at play. It was shops selling the accoutrements of urban wealth that were stripped from shelves—fashionable sportswear and high-end electronics. Brainwashed by a consumer culture that prizes acquisition above all else, these things may have seemed like necessities, even rights. As the country looked hard at the holes in its social fabric, there was a terrifying realisation, that a swathe of this generation were led to take what they thought they needed by force, absent the opportunities to acquire them legitimately.
Half way down the world, in Kenya’s northern province of Turkana, an altogether more desperate fight for resources was intensifying. For centuries the nomadic cattle and camel herders of the Turkana and Pokot tribes have been trapped in an ebbing-and-flowing conflict over pasture and animals. A couple of things have changed, though. Firstly, a step-change in the hardware used in raids has made them far more deadly, far more destabilizing. The flow of cheap Chinese-made, AK-47-pattern assault rifles over the porous borders from Uganda, Sudan and Ethiopia mean that the silhouettes of herders loping across the wide, pale wilderness are no longer topped with their traditional short crooks, but with the menacing hook of a Kalashnikov.
The firearms have made the conflict more lethal, but it is proximity that has driven the violence. Turkana is the frontline of climate change. Always prone to drought and flood, the destruction of what was left of its forests and an upwards trend in temperatures have killed off the already sparse pasture, and driven pastoralists to fight more frequently and more fiercely for what is left to survive in what has become a low-level war for water and for grass.
What used to be 20- or 50-year droughts come with alarming frequency—devastating the county every couple of years. That year, 2011, was one of the worst on record. Thousands upon thousands of animals died, food aid became the only way to survive and the fighting, naturally, got worse.
At 12:45 on September 5, 2011, officers from the New York Police Department responded to a 911 call from East Flatbush. They found four people with gunshot wounds, one fatal—the 18-year-old Tyrief Gary, dead from a bullet to the chest. They were among the 42 shooting victims in New York City that Labor Day weekend. Perhaps the overspill of the sometimes fractious West Indian Day parade had something to do with it, the media mused—perhaps gun control needed tightening.
But what if there was something more base at play, something ultimately more terrifying—an unavoidable determinant of violence. What if it was something environmental, something physiological? What was the commonality between New York’s shootings, Turkana’s fighting, London’s riots?
England’s 2011 summer was overwhelmingly cool, but that second week of August broke the trend. Turkana, normally unbearably hot, was more so—to the extent it burned off what was left of the trickles of water that pass for rivers and bleached the bones of the starving livestock where they fell.
Coincidentally, for September, the Labor Day weekend too was warm in New York City, with highs of 85 degrees, some ten degrees above the average for the month.
What if, alongside all of the social, economic and cultural factors there was something else making conflict ever more likely: the heat. What if, as the temperature rises, the ties that bind societies together start to fray?
Over the past 18 months, researchers, led by Princeton University’s Solomon Hsiang, have been analyzing studies across archaeology, economics, criminology and psychology, looking for the link between weather and violence. There have been attempts in the past to derive some kind of a relationship between temperature and conflict—some quite simply stating that hot countries tend to be more violent, failing to take into account cultural, demographic and political differences. Hsiang et al took a more rigorous approach, tracking the populations of individual countries across climatic variations, discounting the progressive and gradual changes in population and economic development to find the variations in the incidence of conflict that correlated directly to temperature rises.
“In the past, individual studies at each focused on a very specific type of interaction. So some studies looked only at domestic violence. Another study only looked at civil conflict,” Hsiang says.
“We really zoomed out and said that human conflict is a really general phenomenon. It occurs between single individuals. It occurs in small groups, in big groups, and in all cases it’s basically people demonstrating a willingness to harm one another. That’s the common thread between all forms of human conflict, and we thought maybe that in itself represents something about the human condition, and let’s see if that willingness demonstrates any kind of generalized response to the climate.”
What they found was a clear statistical relationship between temperature rises and violence. Personal violence, including murder, assault, rape and domestic violence; intergroup and political violence, such as civil or ethnic conflict, riots and land invasions; and institutional breakdowns, including the collapse of governments, are all amplified by rising temperatures—regardless of culture, level of economic development, geography.
An upwards shift of one standard deviation from prevailing temperature trends increases the risk of riots, civil war or ethnic conflict by an average of 14 percent, they found. The same variation increases the chance of interpersonal violence by four percent. That variation can be as little as two-thirds of a degree in some African countries, or around five degrees in the US.
Generally accepted “business as usual” climate change models predict between two to four standard deviation shifts in global conditions in the next 40 years. The implications are stark. A rise in global temperature means an increase in violence, and not a marginal one. In some countries, the predicted rises could mean a 50 percent increase in the chance of civil war. A future of increased violence is one of inflated human and economic costs
“There’s the question that people are debating—how should we design our greenhouse gas strategies in terms of climate change? What this [finding] does is change that calculus, because it suggests that future climate change will be worse than expected,” says Hsiang, who adds that the research should be valuable to law enforcement and humanitarian officials as they plan their resource allocations.
Breaking the link between violence and temperature, though, is another matter, because although there is a statistical correlation, the pathway for the relationship is, as yet unknown.
“There’s a very large set of potential hypotheses that have been proposed in the literature. We don’t have enough evidence or data to exclude any hypothesis,” Hsiang says. “There’s things like economic performance, which affects the labor market. There’s also questions of migration, issues of income inequality. All of these can be impacted by the climate. We don’t actually know which is the pathway that links these two things.”
The role of resource constraints and the interplay between marginalization and climate is relatively intuitive and well understood.
Climate change is not a great leveler, but exacerbates social inequality through a cruel cycle—resource scarcity leads to marginalization, and marginalization leads to resources being distributed unevenly, exacerbating the inequality of opportunity. On the local scale, the civil violence and violent crime could be a direct reaction to this; the inability of marginalized groups to access the slim pickings in the formal economy, the absence of any kind of political agency driving individuals to circumvent democratic mechanisms and the institutions of state. That certainly seems the case in Turkana, where, pastoralists have been economically and politically isolated for generations.
Without a voice, nothing gets done. The roads washed away by flash floods that rip down from the Ugandan hills are not replaced; the wells sunk by NGOs are not renovated; adaption to the coming extreme weather does not happen.
How that then leads to civil and inter-group violence is, also, relatively obvious. In the developing world, where institutions are weaker and inequality more deadly, it is manifest time and again. It is there in Nigeria’s slide towards disintegration, with the desert encroaching in its north adding to the conflict between ethnicities and religions. It is, surely, one of the factors in Mali’s civil war, where economically disenfranchised communities on the edge of the advancing Sahara were pressed to armed action.
But what about rioting in the developed world? What about the rise in assaults and rapes? That, surely, is not a direct response to resource scarcity.
Craig Anderson, a psychology professor at Iowa State University and the director for the Center for the Study of Violence, has long proposed a link between high temperatures and violent crime. Using data from Minneapolis and Dallas, he showed that there was a linear—possibly causal—relationship between violent crime and temperature, positing a range of behavioral factors and physiological ones—laboratory studies show that, as the temperature of a room rises so do the tempers of its inhabitants.
“There is considerable evidence that when people are uncomfortably hot, they become more physically aggressive,” Anderson says. “They tend to interpret minor annoyances as being more serious and intentional provocations than they would in comfortable temperatures, and this tendency tends to lead to more aggressive behaviour that sometimes escalates into violence.”
He, too, points out that resource scarcity is a possible vector of violent conflict, and that it has longer-term consequences.
“Rapid climate change and the resource shortages and conflicts they produce lead to increases in a host of known risk factors for the development of young people into high violence-prone youth and adults. Such risk factors include poverty, poor pre-and post-natal nutrition, broken homes, unstable living environments, and so on.”
Whether this research will drive any meaningful action is a function of how strong the provable links are, and whether breaking the cycles of climate change and violence is ultimately possible, given current inaction on reducing carbon emissions.
“Not knowing the mechanisms has one conclusion, that we need to push more research on that field. Part of this project is really demonstrating that we don’t know the mechanisms yet, but that critical and important question for the future if we do want to interfere with the link between climate and conflict or try to break that link,” Hsiang says.
“I think the take home conclusion is that all forms of human conflict across the world and throughout history have exhibited a response to changes in the climate. They are not completely inert with respect to the climate. As the climate changes, our person-to-person or group-to-group interactions change. As we look forward into the coming centuries and we’re beginning to become much more active players in determining what the climate is going to be, let’s think about what we want it to be in terms of how it affects how we interact with each other.”
