A study conducted by researchers from the University of California in Davis has revealed a possible connection between climate change and increased violence due to competition for limited resources in the past.
The impacts of climate change are wide-ranging, causing issues such as forest fires and a reduction in the growing season for essential crops. These changes have also affected the economy and, predictably, have led to a rise in interpersonal conflicts and homicides.
The University of California researchers discovered an increase in violence during periods of climate change in the southern central Andes between 470 and 1500 CE. Specifically, during the medieval climatic anomaly from approximately 900 to 1250 CE, there was a warming trend leading to drought and the collapse of early Andean states.
The researchers propose that climate change and competition for limited resources in the region may have stimulated violence among the population during this time. In order to assess levels of interpersonal violence, the study analyzed cranial injuries of individuals from that period, a common method used by archaeologists. “We found that a decrease in precipitation was predictive of an increase in head injuries,” stated Thomas J. Snyder, the study’s lead author.
The study also found that a 10 cm decrease in annual ice growth on the Kelkai glacier corresponded to a doubling of the likelihood of interpersonal violence.
Interestingly, these patterns were not observed in coastal and intermediate-sized regions. It is possible that inhabitants of these areas adopted non-violent methods for conflict resolution or were less impacted by the changes. The greater diversity in agriculture and economy in these regions may have acted as a “buffer” against the onset of climate change.
The Andes study offers a unique opportunity to study human responses to climate change due to the region’s extreme climatic variability, well-preserved archaeological finds, and reliable records.