Hazards of One Crop Economy

A Cahal Pech pyramid and site of many royal tombs

Claire Ebert

Archaeologists have long hypothesized that the ripple effects of climate change on agriculture may have played a role in the collapse of Classic Maya society. A new study combined multiple scientific methods from across disciplines to examine the links among societal resilience, dietary diversity, and climate in the Maya.

Anthropologist Claire Ebert of Northern Arizona University and four colleagues used the remains of fifty individuals from the ancient Maya community of Cahal Pech, Belize to examine links between climate and diet from the Preclassic through Terminal Classic periods (900 BCE–900 CE). Stable isotope data documented from burials of the Preclassic and Early Classic periods suggest that both elite individuals and commoners ate a diverse diet of hunted animals, wild plants, and maize—a crop so culturally significant that it was deified during the Late Classic. This broad diet may have provided a buffer for Maya when, as paleoclimate records indicate, a severe multi-century drought arrived between 100-300 CE. The picture changed during the ensuing Terminal Classic period, between 750 and 900 CE.

Restricted nitrogen and carbon stable isotope values indicate that high status individuals, identified from their central burial location and elaborate tombs filled with grave goods, had evolved narrow, specialized diets comprising mainly maize, a drought-intolerant crop. Ebert and colleagues suspect this specialization, which resulted in increased vulnerability to food shortages during a long drought from 820 to 900 CE, was likely a factor contributing to the failure of the Cahal Pech socio-political system.Their results suggest that Maya of the Late Classic Period faced challenges of food insecurity alongside the increasing social inequality, rapidly expanding populations, and environmental degradation documented by other studies. Societies heavily reliant on agriculture become vulnerable in situations of sudden change, such as the onset of drought. 

Depending heavily on one type of food source—such as maize—increases that vulnerability. “If we can understand how the Maya coped with severe drought—successfully or not” says Ebert, “then we might be able to apply similar approaches to deal with [our own] changing climate conditions.” (Current Anthropology)