By Lionel Beehner
The spike in so-called "green-on-blue" killings by Afghan troops has prompted at least one theory by General John Allen, America's top commander there, and others: The weather made them do it. The combination of Ramadan, whereby Afghan Muslims are prohibited from drinking water from dawn till dusk, and the humid August weather, has made these troops especially twitchy. In Syria, a related theory links the success of rebels to the weather, in particular to rainfall patterns. C.J. Chivers, blogging recently in The New York Times, found the prospect of rebel victories aligns with the northern region's unpredictable rainy season. Rain, his theory goes, leads to abundant harvests, which in turn fuels the insurgency by keeping its fighters well fed. "Revolutions need many things," Chivers wrote, "but one element is essential: food." And Nature magazine made waves last summer after publishing an article claiming that the warming effects of El Niño can explain over one-fifth of all civil wars.
Can abnormal climate patterns really predict political violence, much less predict green-on-blue attacks by Afghan forces or future civil wars? The answer is: It’s complicated, but generally no. The conventional wisdom among Neo-Malthusian scientists is that higher temperatures lead to lower agricultural yields, which can heighten conflict due to droughts, food insecurity, and the social dislocations of migratory rural workers. Others stress the internal migration of rural workers in search of jobs to cities or regions less vulnerable to climate swings or the social unrest this dislocation creates.
The push to link climate change to conflict goes back decades, but caught steam in 2007, when researchers at the UN Environmental Program described in detail how climate change and environmental degradation were partly responsible for civil violence in Darfur. The Sahara desert, the researchers found, was advancing by a mile or more per year in some places, rainfall had dropped between 30-40 percent over the past few decades, and unpredictable climate patterns had triggered civil wars across Africa, but especially in areas with poor access to arable land or water. Climate change, in effect, was creating “unavoidable pressure on people through migration, displacement, food insecurity, and impoverishment, possibly ending in conflict.”
Similar studies emerged around this time. UC Berkeley's Edward Miguel predicted that given current temperature trends, incidences of armed conflict might increase by more than 50 percent by 2030, or an additional 393,000 battle deaths. Another study found that natural disasters due to rapid climate change, including droughts or floods, increase the risk of civil wars, especially in poorer countries. Last January, the Journal of Peace Research devoted an entire issue to climate change and conflict.
The recent uprisings across the Arab world have also renewed inquiry about the effects of climate change on collective action and political violence. One theory posits that unusually warm temperatures in Russia in 2010 hampered food production, which in turn raised food prices globally and was one factor that contributed to the recent instability across the Arab world. Another theory drawn from social psychology has found that extremely warm weather can increase aggression by indirectly heightening feelings of hostility and aggressive thoughts. A third hypothesis holds that political violence does not originate with climate variations per se but does ebb and flow as potential fighters move in and out of farming jobs.
Environmental stress can also bring about state breakdown, opening up structural opportunities for rebel movements to form from the bottom up or for elites to challenge state authority from the top down. A final theory holds that relative deprivation and grievances driven by environmental stress make conflict more likely. That is, it is the distribution, not availability, of natural resources, which contributes to economic exploitation, expropriation, and eventually conflict.
During most bouts of bad weather in adversely affected regions, however, conflict is not the norm. Many countries that suffer unpredictable patterns because of, say, El Niño—Niger, Burkina Faso, etc.—rarely see violence. Scholars who privilege grievances as a result of environmental degradation —e.g. scarcity of resources, overpopulation, etc.—tend to over-predict violence and fall prey to environmental determinism, without fully accounting for why internal violence more often than not does not erupt. Also, states and societies generally can often adapt to severe climate patterns. Violence, after all, is just one means of adaptation among many; switching crops or migration being others. Neo-classical scholars maintain that agrarian societies have strong market-based mechanisms for adaptation. Climate patterns and conflict are complex processes that interact with several intervening variables. That is, environmental shocks can lead to poverty and weaken states, which then makes it more difficult to mitigate against their effects, thus fueling violence and creating a vicious circle. But often it is unclear which way the direction arrow goes.
Part of the problem linking climate change to conflict stems from methodological flaws. A case in point is the aforementioned Nature study, carried out by researchers at Columbia University’s Earth Institute. Like a lot of quantitative work, the study focused on macro-level conflict by country, despite the fact there is substantial variation within countries in both patterns of violence and climate phenomena. This kind of research rarely captures limited forms of social conflict and collective action short of civil wars. Moreover, climate change is measured in longer-term trends and annual variations, which are too static to map onto wider conflict patterns. The authors, for example, rely on an over-aggregated heuristic, dividing the last half-century into El Niño (treatment group) and La Nina (control group) years and the world into two regions "tele-connected" or "weakly affected" by El Niño. This assumes that the ecology of the tropics is monolithic, when we know it is not. On average, El Niño leads to hotter and drier conditions for affected regions away from coasts. But it can also produce floods along the coasts due to increased ocean evaporation from warming that can induce greater rainfall. To understand how El Niño acts as a driver of conflict requires an explanation of such diverse climatic phenomena, as presumably rebel violence would vary in response to droughts versus floods.
So what does all this mean for Syria, Afghanistan, and other countries embroiled in conflict today? There is ample evidence that insurgent attacks in Afghanistan pick up after the snow thaws—a so-called “spring offensive." On Syria, there is some evidence of the effects of rainfall patterns on violence. Edward Miguel has found that rainfall shocks impact civil war through the channel of negative economic growth. Yet others have found that civil conflicts are reversely correlated with rainfall patterns—that negative rainfall shocks actually reduce the risk of conflict outbreak. Hence, the success of Syrian rebels last spring, when rainfall and crop yields were higher than usual, could very well be a coincidence.
Examining micro-level violence data and precipitation levels by province in Ethiopia and Eritrea during their 1998 border war, I found that months with highly volatile precipitation swings in any province were not correlated with heavier violence. Perhaps climate patterns are more robust at predicting other forms of collective action short of violence, like we might see in the Arab Spring? I looked at land occupations by peasants in Northeast Brazil, a popular form of protest in one of the hemisphere’s poorest regions. Predation, or the forceful extraction of property from others, is presumably one form of adaptation landless people choose in response to environmental shocks. Yet though I found some correlation between precipitation levels and land occupations at a macro level, upon closer inspection—that is, when the data is broken down by province and by month from 1997-1999, when an El Niño slammed into the region—the results wash out. The province that saw the most conflict and land invasions, Pernambuco, saw the fewest precipitation swings as a result of El Niño.
This is not to suggest that climate anomalies have zero impact on patterns of violence. In some poorer parts of the world vulnerable to environmental swings, surely unemployed farmers take up arms after bad harvests. But again, climate factors interact with so many intervening variables that it is nearly impossible to isolate climate factors as the sole motivator of violence. At best, all we can say is that extreme or unpredictable climate events may exacerbate conditions on the ground that can heighten the likelihood of violence, but that gives us little predictive power.
The effects of climate change on conflict are complicated. To say that the heat or rains are influencing attacks in Afghanistan or Syria is an educated guess. After all, perhaps the only thing harder to predict than the weather may be patterns of civil violence.
Lionel Beehner is a fellow with the Truman National Security Project, a doctoral student at Yale University, and a term member at the Council on Foreign Relations, where he is a former senior writer.
[Photo Courtesy of United Nations Photo]