Photo courtesy of Dave Bennion
The Hopi people of the southwestern US have a story: During a long drought when corn wouldn’t grow, the tribe began running out of food. Two children made a toy hummingbird that, as they tossed it into the air, came to life. It flew to the center of the Earth and begged the god of fertility for help. And he made it rain.
For as long as we have been telling stories, we have been telling them about weather, trying, in the absence of scientific certainty, to understand its influence on our lives. In the small body of research there has been on the topic, we’ve found that wind and heat can make us cranky, violent, sick, and suicidal. We honk more horns, have more headaches, kill more people and, according to a recent study, even fight more wars.
“Warming increases the risk of civil war in Africa,” reads the title of a paper published in PNAS in November that looked at the relationship between temperature and armed conflict in the sub-Sahara. Researchers found that violence was more likely to erupt in years with hotter weather. “If the temperature goes up by just one degree, crop yields can decline by 20 percent or more,” explains Marshall Burke, one of the study’s authors. “Since 75 percent of poor Africans are engaged in agriculture for their livelihoods, these small changes can have big influence on their incentives to join rebellions.” It’s a frighteningly simple logic that suggests a frighteningly simpler one: The hotter Africa gets, the more violent a place it will become.
The Hopi had a similar appreciation for the weather, though they made sense of it not through research but narrative. Stories like theirs give us a record of how humanity has coped with and tried to escape the influence of its environment. Many of these stories have been unknowingly shaped by the scientific thinking of their time, reflecting our bizarre and often specious attempts to put scientific explanation behind the still largely mysterious feeling we get that, when the weather changes, so do we.
A Mighty Wind
Hans Christian Andersen’s 1862 story, “The Ice Maiden,” describes the weather in an Alpine pass: “The wind blew from the south, an African wind; it suddenly sprang up over the high summits, like a foehn, which swept the clouds away.” The warm “foehn” wind Andersen refers to is notorious for causing bizarre human behavior. Suicides, domestic violence, depression, and nausea have all been attributed to the Swiss foehn, earning it a place in countless stories and superstitions.
But, as University of Wyoming anthropologist Sarah Strauss points out, had Andersen written this passage two decades later, his description of the wind would likely have been completely different. The scientific thinking in 1862 was that a wind as warm and dry as the foehn could come only from Africa—that is, it could only be “an African wind.” But within 20 years it was largely understood that the foehn’s peculiar properties could be explained by the distinct way it develops. When air is forced quickly up the side of a mountain range, it cools and forms into a cloud. Near the peak of the mountain the cloud dumps its moisture as rain or snow, leaving a dry wind that heats up as it rushes down the opposite face. The temperature change it brings to the villages it blows through can be striking. The largest recorded change caused by a foehn-type wind was in the Black Hills of South Dakota in the winter of 1943 when, in the small town of Spearfish, thermometers rose 49 degrees in only 2 minutes.
The German-Swiss author Herman Hesse pondered the foehn’s effects in his 1904 novel Peter Camenzind about the life of a fictional Swiss man by the same name. Hesse was likely drawing from his own experiences when he wrote that Camenzind felt the foehn had invested his village in the Alps with a “penchant for melancholy.” Hesse had spent six years of his childhood living in Basel, Switzerland, a place Camenzind visits in the novel where effects of the foehn have long been reported. “For people who live in areas where foehn winds blow, there is an overwhelming amount of anecdotal evidence for these effects, but there has been only a small amount of scientific research to back them,” says Strauss.
Foehn effects are so well accepted today in Switzerland that publications for foreigners working in the country include warnings about them, cautioning that some, though not all, suffer from the “oppressive” winds. Swiss lore states that the foehn’s effects manifest variably, based on the sex and age of its victims. This experience is perhaps best left to Hesse’s Peter Camenzind for interpretation: “As a child I was afraid of the foehn, even hated it…later my love of the foehn deepened…nothing could be stranger or more delicious than the sweet foehn fever that overcomes the people in the mountain regions, especially the women, whom it robs of sleep, tantalizing their senses.”
In the 1950s and 60s, a team of Israeli scientists began experimenting scientifically with the foehn’s influence on different age groups in Jerusalem; it was thought at the time that half of the city’s population suffered from some sort of foehn-related sickness. The foehn they studied was not that of the Swiss Alps, but a Middle Eastern wind known as the khamsin. The khamsin is as notorious an arbiter of human behavior as the Swiss foehn. When it blows, automobile accidents increase, and crime rises as much as 20 percent. And like those in Switzerland, judges in some countries take a lenient attitude toward crimes committed during the khamsin—a fact that conceivably only increased crime when Time magazine later reported it.
The Israeli team claimed that the khamsin increases the production of the hormone serotonin, causing young people to develop migraines and to become nauseated and violent. Older people, they said, have a different reaction, becoming fatigued, apathetic, and depressed as their production of adrenaline decreases.
The team’s explanation for the findings was the controversial idea of “air ion concentration.” Ions are atoms or molecules that have either lost or gained electrons, resulting in a net positive or negative charge, respectively. The unusually high concentration of positive air ions in certain weather fronts like the foehn or the khamsin was first reported in 1901. A study in 1963 had also claimed that 30 percent of the population exposed to the khasmin began to feel the negative effects of the winds as soon as the concentration of positive air ions increased—24 to 48 hours before the winds perceptibly started to blow.
For the Israeli researchers, all this added up to a simple chain of meteorological and physiological effects: When the wind blows, it accumulates positive ions. This causes a rise in serotonin production, which in turn leads to nausea, vomiting, migraines, and a number of potential other side effects.
The researchers’ proposed treatment for these effects was a machine known as the “ionotron” that generated large numbers of negative ions. As far back as the 1930s German doctors had attempted to treat bronchitis and asthma by having patients inhale negative ions. It was later found however, that in many of these cases the generators weren’t powerful enough to produce ions at all. In the US, ion generators were sold as a treatment to all sorts of diseases until the FDA banned them from being marketed for as a cure for medical illness. Today, ion generators are touted as a treatment for Seasonal Affective Disorder, a depression observed in some individuals who live in areas with long dark winters.
There is some evidence that ions can have an effect on us, but scientists are far from settled on the issue of what role, if any, atmospheric ions play in weather-related illnesses. The late physicist Niels Jonassen commented in 2002, “I have never been able to find any hint of a trustworthy theory explaining how a unipolar ionization of the air mass could take place, let alone explain how the charge could be carried hundreds of miles over the mountains without dissipating. I have also not seen any proper scientific papers demonstrating the excess of positive ions in these winds.”
True or not, the ion explanation has changed the way we talk about weather. In her 1968 essay “Los Angeles Notebook,” which reflects on living in a city with another notorious foehn wind, the Santa Ana, the essayist Joan Didion popularized a deterministic interpretation of the foehn’s power over us. “To live with the Santa Ana is to accept, consciously or unconsciously, a deeply mechanistic view of human behavior,” she writes, “…positive ions are there, and what an excess of positive ions does, in the simplest terms, is make people unhappy. One cannot get much more mechanistic than that.”
The Heat Hypothesis
Many of the scientists studying the effects of weather on human behavior—not just as a result of foehn winds—don’t agree with the deterministic view of the weather’s impact on us. “People very often use that word ‘mechanistic’ when talking about the effects heat has on violence,” says Craig A. Anderson, a psychologist at Iowa State University who has been studying the link between temperature and human behavior for the past 30 years. “Usually that is a sign that they haven’t actually read any of the papers we’ve written.” He began studying what is now called the heat hypothesis—which states that as the temperature increases, so does the likelihood of aggression—as a graduate student in 1979, when he looked at the relationship between heat waves and rioting in the United States. Since that time there has been a slew of studies finding that when the temperature goes up, so does the likelihood of violence.
On the surface, it seems that the dismal mechanistic view might be appropriate: The second half of the 1960s saw an explosion of race riots across the United States. On August 11 1965, a riot erupted in the Watts neighborhood of Los Angeles. Six days later 34 people were dead and more than a thousand injured. In Detroit during the hot summer of 1967, a riot erupted after a raid at an after-hours drinking club. After five days and an intervention from the US Army, 43 people had been killed, and more than a thousand injured. Over a hundred major riots occurred in cities such as Washington DC and Newark during what are now known as the “long, hot summers.” Last year the New York Times published a homicide map charting when and where each reported murder since 2003 in the five boroughs occurred. It’s easy to see from the map that during the summer months, killing increases. But to say that heat caused the race riots or homicides in New York misinterprets what is going on. “We’re talking about dynamic systems at a physiological, social, and political level. There is nothing mechanistic about them,” Anderson says.
Both Anderson and Burke are now working on using their research to predict and address problems that may result from climate change. For Burke, his findings about the relationship between heat and war in Africa take on a particular urgency when considered in light of near-future temperature changes predicted by climate models. “We find these large possible increases by 2030,” he says. “To us, that points to the importance of helping prevent violence by making investments to help agriculture adapt to higher temperatures.”
The objective of this research is not to uncover a frighteningly mechanical connection between the environment and us, but to understand and better respond to the effects weather has on our lives. Ancient Egyptians danced to make it rain. The Romans had a stone they would drag to the senate floor and douse with water as they made sacrifices during times of drought. More recently, people sucked negative air ions from generators to attempt to mitigate a myriad of effects from weather. Now, we have the ability to supply farmers with more heat-tolerant crops and to offer global aid to African countries in times of drought. We can install air conditioners in schools, prisons, and other institutions that are prone to violence. In short, our rain dances are getting better.
In fact, work on Anderson’s heat hypothesis seems to suggest a practical usefulness for the stories we’ve been telling all along about weather. There is evidence that if people are aware that they are irritable because it is hot, they are better able to suppress violent responses that lead to assault and murder. By preserving information about the weather’s ability to impact us, these stories may serve to limit its more insidious effects. When we consider our relationship to the environment, perhaps we should internalize another thought from Didion, the opening sentence to The White Album, her 1979 essay coping with a country stricken with paranoia: “We tell ourselves stories in order to live.”
Originally published December 21, 2009