UMaine Professor Links Natural Disasters to Demise of Ancient Peruvian Society
Contact: Aimee Dolloff, (207) 581-3777; Dan Sandweiss (207) 581-1889
ORONO, Maine — As global climate change leaves us wondering how we will prosper in the coming century, archaeologists look to the past to learn how our ancestors dealt with such problems. The story is not always encouraging. University of Maine anthropology professor and graduate dean Dan Sandweiss and his colleagues have recently found one instance where rapid change in climate and environment led to the downfall of one of the New World’s first complex societies.
In a report published this week in Proceedings of the National Academy of Sciences, Sandweiss and his colleagues note a correlation between the collapse of an ancient society in Peru’s Supe Valley and natural disasters, including earthquakes and flooding brought on thousands of years ago by El Nino.
“We suggest that there’s a relationship, and the end result was that [these communities] were unable to maintain their level of productivity,” Sandweiss said.
The study focuses on several sites excavated in recent years by Peruvian archaeologist Dr. Ruth Shady, a co-author of the article.
Shady is the director of the Caral-Supe Special Archaeological Project and has been working in the Supe valley since 1994. She currently has seven sites under excavation, including Caral, the largest Late Preceramic monumental site in South America.
Early Supe society was built on a combination of fishing and agriculture, making both coastal and inland communities equally vulnerable to disaster when earthquakes shook up the desert landscape and El Nino instigated flooding.
“This maritime farming community had been successful for over 2,000 years, they had no incentive to change, and then all of a sudden, ‘boom,'” says Mike Moseley, an anthropology professor at the University of Florida. “They just got the props knocked out from under them.”
The floodwaters carried the loose debris into rivers negatively impacting the ancient fishing industry, and winds created sand ridges that ruined farm land.
Prior to 6,000 years ago, Sandweiss states that El Nino was absent for several millennia. Gradually it began to occur, and then about 3,000 years ago El Nino events became more frequent.
“These are processes that continue into the present,” Sandweiss said. An example is the major earthquake that occurred south of Lima, Peru a few years ago.
“It’s possible that El Nino will become more frequent as global climate warms.”
Current technology and awareness that these types of events are likely to occur should help in planning to minimize the impact and damage. For example, China has been successful in using vegetation to create screens that reduce the impact of blowing sand.
To better understand the correlation between climate, environment, and the rise and fall of early coastal communities in Peru, Sandweiss intends to continue his research and field work.
“We want to go back and get a much more detailed history of the environmental changes,” Sandweiss said. The researchers intend to core additional samples from just offshore, to help create a record of change by identifying and dating the once-living organisms found in various layers of the cores.
Other authors of the paper are David Keefer, an earthquake hazards geologist and geoarchaeologist associated with the University of Maine’s Climate Change Institute, and Charles Ortloff, a consulting engineer who has worked in the Andes for three decades.