Phillip Trella studies bones from the ruins of the ancient cities of Upper Mesopotamia. After several millennia, the cities have been reduced to mounds, the detritus of human habitation piling up year after year so that the sites are elevated above the plains. A specialist in zooarchaeology, Trella can recognize a goat tibia with a glance. Turning a bone over in his hands, he can identify the species, age at death, sometimes sex, whether it was domesticated and how it may have been butchered and cooked.

“There is a sense of awe that people feel about ancient people that lived in complex societies,” says Trella (Grad ’00, ’10). “I think we can more easily relate to people living in early cities with buildings and monuments, with government and class hierarchies, than we can to hunter-gatherers. I think the reason for this is that we believe in a socio-evolutionary narrative that suggests that we share certain commonalities with other ‘civilized’ societies.”

One feature that is common to most civilizations is that they go through cycles of growth and disintegration. Why do they fall apart? History documents the rise and fall of vast empires—Rome, Greece, the Maya, Persia and, yes, Mesopotamia. While examining the evidence left by ancient cities, Trella and other archaeologists develop theories about the nature of complex societies that inform our present civilization—the largest and most complex in history.

Agricultural practices, societal hierarchies, use and abuse of resources—all come under their scrutiny.

“As a group, you’ll find that anthropologists are very wary of the things being done now that cause environmental degradation,” says Patricia Wattenmaker, an associate professor of anthropology at UVA whose research focuses on the archaeology of complex societies, particularly those in the ancient Near East. “That is because we’ve seen how local environmental degradation affected societies of the past. To see environmental degradation on a global level is upsetting, because for us, unlike the ancient people who left their cities to become nomads, there is nowhere else to go.”

The study of early civilizations brings archaeologists to the Near East, where the ruins of several-thousand-year-old city-states show evidence of the first agriculture, irrigation, animal domestication, writing and organized religion. Modern states—Turkey, Syria and Iraq—now exist in territory that was once Assyria, Babylonia and Sumer.

The search for knowledge has drawn both Trella and Wattenmaker to Upper Mesopotamia, which spans modern Iraq and part of Syria and Turkey. Here, in the Fertile Crescent, humans first domesticated animals and cultivated crops like wheat and barley. Five and a half thousand years ago, city-states in the region left behind the earliest evidence of writing and elaborate burial rites for kings. Trella draws on 14 years of experience, which includes sites in Turkey and Syria, where he studies the Early Bronze Age, between 2500 and 2000 B.C. He uses bones, both animal and human, to trace changes in population density and food sources that reveal a compelling narrative of early civilization—and how we view progress.

“From the vantage point of the modern industrialized world, history appears to many to be a slow progression from less complex social organization to more complex—hunter-gatherer to chiefdom to city-state to empire,” Trella says. “This notion of progress that leads inexorably to us—Western civilization—has big value implications, the most significant being that things are getting better. And that complex societies are better.”

But the cities didn’t simply get bigger and better. The archeological record reveals that different eras showed vastly different populations in the cities as they went through boom-bust cycles. Cities grew for several hundred years, then dwindled as populations dispersed into the countryside—and later grew again.

What fueled the growth cycles? Trella points to intensified food production and increased specialization among citizens. When not everyone had to work to produce food, city residents could become warriors, priests, traders and kings. They erected stone buildings; they irrigated fields. They invented writing.

But where is the tipping point that caused cities to decline and populations to disperse?

“There was a time,” Trella says, “when archeologists were looking for disasters to explain it, something spectacular like Pompeii being buried in ash by the eruption of Mount Vesuvius. But I would argue that it is comparatively rare for a decline to be due to external causes like a natural disaster.”

Instead, some of the same factors that allowed cities to grow may have ultimately caused them to disintegrate. Trella’s studies in Upper Mesopotamia indicate that farming was intensified to provide more food to support growing populations. With limited transportation, cities depended on the fertility of nearby land. When populations were small, fields were left fallow biannually and used as grazing land for animals that fertilized the soil with their dung. Population growth changed this practice and potentially motivated the use of city wastes to fertilize fields. Analysis conducted on animal bones indicates that after several centuries of habitation, city dwellers no longer pastured their livestock in fallow fields, but instead moved them farther into the countryside, where their dung no longer benefited crops. All of these factors likely decreased agricultural sustainability.

Food and farming practices play no less a role today in the prosperity of nations. Trella points out that food production has been revolutionized in the past 65 years, mostly due to the application of petrochemical fertilizers and pesticides that have resulted in increased yields.

“Is it socially sustainable, environmentally or economically stable? There is a growing body of data to suggest that it’s not,” he says. Increased yields have helped to support the population explosion from approximately 3 billion to 7 billion people between 1960 and 2010. Identifying a tipping point between helpful and hurtful strategies is difficult, because perspectives differ.

“If industrialized agriculture gives way to a more environmentally sound model, this may very well drive prices up, and for the poorest people that will be seen negatively,” Trella says.

Wattenmaker draws comparisons between contemporary and ancient Mayan food production. As agricultural yields were declining during the Mayan Classic period, attempts were made to address the crisis through technology, and the Mayans developed a new agro-engineering system. Ultimately, these efforts were unsuccessful. “Today, many believe that scientific innovations will protect us from widespread, long-term food and fuel shortages,” says Wattenmaker. “It’s important to realize that ancient societies also relied in part on scientific advances to see them through crises. Ancient societies, like many modern ones, believed they were exceptional and that their unique characteristics would protect them from environmental hardships.”

New research that Wattenmaker is doing in Upper Mesopotamia will test the theory that at the same time that agricultural practices were changing, society was becoming more socially stratified. A more complex hierarchy developed, and economic inequality increased. The high demand for craft goods and food surpluses among both elites and nonelites likely led to further intensification of the food production system.

“Stratified societies have classic vulnerabilities,” says Trella. “The elites at the top may be increasingly removed from what is happening ‘on the ground,’ yet, the goals of the elites may supersede all else.”

Trouble can arise when the orders of the elite—a modern parallel can be government regulation—have unintended consequences. For example, “In Upper Mesopotamia, if elites gained more control over food production, their efforts to increase wealth generation may have resulted in disrupted production,” Trella says. Both Trella and Wattenmaker say that more research is required to determine exactly how the social organization of ancient cities influenced food production.

“Some archaeological findings do reveal that ecological crises were preceded by increased social stratification, although a causal relationship is more difficult to demonstrate,” says Wattenmaker. “The disintegration of the Old Kingdom state in ancient Egypt involved both overexploitation of state workers and a series of poor harvests, among other factors.”

Were the citizens of ancient cities victims of too much of a good thing? “They tried to maximize their resources in the short term at the expense of their long-term survival,” says Trella. “The overextension of practices that were at one time helpful became destructive.”

Wattenmaker’s research at the site of Kazane, in Turkey, suggests that societies set themselves up for environmental disasters due to factors such as unchecked rivalries between polities, steadily escalating maintenance costs—for road systems, public buildings and military installations, for example—and, she says, “ideologies that emphasized economic expansion—in short the kinds of issues that may cloud our judgment on ecological issues today.”

In his classes at the University of Virginia, Trella examines the collapses of ancient states, steering students’ attention to buried cities and “lost towns” in Egypt, Mesopotamia and Mesoamerica. He delves into the value of civilization; questioning whether living in large-scale complex societies is always good for the individuals who live in them.

“Part of the problem is that we don’t define what ‘good’ is. We assume that societies like our own are somehow ‘better’ or more ‘civilized.’ We need to be specific about what variables we’re actually measuring,” Trella says. For example, if the goal is generating wealth, then highly stratified, complex societies can accomplish more. But “other variables might yield very different insights.”

Health is one variable that is a good indicator of quality of life. Human bones reveal that many of the people living in cities during their heydays had impoverished diets, suffered from more disease and infant mortality, and lived shorter lives than their nomadic counterparts. “Though certainly the so-called collapse of a city-state could be surrounded by a great deal of suffering,” says Trella, “if overall health is the standard, then the people who lived during the centuries afterward might have had a better quality of life than city dwellers ever did. Complexity itself can impose harsh demands on people.”

With so many variables, how do we distinguish between real threats to society and problems that seem frightening but might not have long-term consequences?

“Catastrophes like 9/11 and Hurricane Katrina affect a great number of people emotionally and economically and are writ large in our memories,” Trella says. “But the real vulnerabilities, or those that most often precipitate disintegration, are things that are taken for granted, such as the incredible degree of interdependence necessitated and produced by the global economy.”

The oil embargoes of the early 1970s, for example, or the economic downturn of 2008 reveal our vulnerabilities, he says. “If one component of the overall system changes or ceases to function, the consequences can be quite large.”

Wattenmaker acknowledges that being part of a large civilization has an upside. “Certainly, I enjoy a lot of comforts and advantages because I live in a specific set of circumstances in a complex society. Medicine, universities and computers all benefit me,” she says. “But as an anthropologist I also try to step outside of my own culture and understand why I may value the benefits of civilization while overlooking or downplaying some of the costs. The archaeological record reminds us that the legacy of ancient state societies includes not only palaces and writing, but also institutionalized poverty and unsustainable farming practices.”

Cataloging evidence from old bones of the long-ago costs of supporting a civilization, Trella doesn’t have a prescription for the future. “Every situation is unique. Every moment in history has its own challenges.

“But I do believe that our ideas about the goals of our society are powerful. We allocate our resources according to our ideas,” he says. “I can only hope that when people dig up the archeological artifacts left over from our society they won’t think, ‘They were their own undoing.’”

Associate professor of anthropology Patricia Wattenmaker and anthropology graduate student Phillip Trella (Grad ’00, ’10) with various artifacts in the zooarchaeology lab in Brooks Hall. The skeleton (center) of a modern-day sheep is used for comparative purposes to help identify bone fragments. Norm Shafer