During the austral winter months, a veil of gray mist shrouds the coast between the Tambo and Ilo rivers in southern Peru, but the soil is a crumbly, faded brown year-round. The few plants that can survive in such harsh conditions are scraggly and wind-whipped. Though the trees are long gone, stumps jut out of the hillsides like half-exhumed skeletons.
It looks like the scene of a post-apocalyptic Hollywood drama, and it is, in many ways, a dead landscape. But it hasn’t always been this way. The remains of stone-faced terraces and ditchlike irrigation canals are evidence of the area’s agricultural past. Today, however, a few lonely farms remain.
Nearby, one of the world’s largest industrial copper smelters has sent plumes of sulfur dioxide into the air since the 1960s, before significantly cutting back its emissions just a few years ago. At first glance, it would be easy to blame the region’s rapid desertification on the smelter. But Gregory Zaro, an assistant professor of anthropology and climate change at the University of Maine, sees things a little differently.
“If you were to make a quick judgment, you could say, ‘Look at that smelter. That’s the reason.’ But the smelter is coming in very late, at the tail end of a process that took five or six centuries,” says Zaro, who is one of a handful of researchers in the world studying this region of Peru. “Desertification as a process often includes both human and nonhuman drivers. Human agents most often stem from agricultural mismanagement, overgrazing, deforestation and industrial activity. Each of these has been present at some point in this study region over the past 600-800 years, and often overlapping. What I can do is use desertification as a measuring stick to gauge how the landscape has changed and what role we have in that change.”
Did centuries-old agricultural practices deplete or enhance the soil? Did deforestation and overgrazing catalyze desertification of southern Peru’s inland hills? Was past or recent desertification a slow or rapid process, either in the ancient past or more recently?
While not the only way humans impact the environment, agriculture is of particular interest to Zaro because it involves deliberate manipulation of the landscape, with intentional and unintentional consequences. Looking at climate change from an archaeological perspective allows Zaro and his colleagues to better understand the way human activities have shaped the environment – and, equally important, how they have not.
“We’re beginning to understand how humans have had an impact on the environment deep into the past,” Zaro says. “It really questions what benchmarks we set over ‘natural’ environments. What we’re inheriting today are environments people have manipulated for thousands of years.”
Zaro became hooked on anthropology, archaeology and Spanish as a teenager, when his father took him to Peru. While working on his master’s degree at the University of Chicago, he spent time on the northern coast of Peru, a hotbed of archeological research.
His Ph.D. work at the University of New Mexico led him south. Because the southern Peruvian coast is less extensively studied, thus less crowded, it allowed him to work more closely with his advisers, who had spent time researching in the area earlier in their careers.
“As a student down there, I saw a real opportunity to understand a very unknown area,” Zaro says.
As a professor, he continues to see that opportunity. The Cola de Zorro site has been marginalized on both a community and, he argues, a scholarly level. He researches from the perspective of historical ecology, which views the evolution of landscapes as the result of the interplay between human and nonhuman processes. And this abandoned farming area was ripe for exploration.
“This whole coastline was very different 500 years ago than it is today,” Zaro says. “I would love to be transported back in time just to see what this place looked like in its heyday.”
Though not the same as a time machine, anthropology, geology, soil chemistry, paleoethnobotany, and zooarchaeology combine to provide a historical view of land use on the site. Individually, these research areas are pieces of the overall climate change puzzle. Together, they may not entirely solve the puzzle, but they offer a much more detailed record of what happened.
By teasing apart different events – light and intensive farming; the building of homes, cemeteries and terraces; industrialization; and the desiccation of the landscape – and when they occurred, Zaro and his colleagues can begin to understand what role humans have played in long-term environmental change.
“Geologically speaking, humans are late arrivals on the planet,” Zaro says. “To put humans in the context of continuous change, there were billions of years of change without us. When we talk about sustainability, what we really need to think about is how we can successfully manage change.”
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