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.”
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.