Tree rings point to drought as trigger of social conflict

Analysis of Polylepis tarapacana tree rings in the Bolivian Altiplano reveals a severe drought between 1316 and 1371 that coincided with the abandonment of vulnerable valley villages in favor of fortified hilltop sites (Pukaras). This evidence supports the hypothesis that water scarcity for consumption and irrigation led to social conflict. The document further notes that contemporary warming, glacier shrinkage, and increasing demands from mining, agriculture, and population growth are heightening the risk of future water shortages and political-economic conflict in the region.

• Tree-ring analysis of Polylepis tarapacana, which grows at elevations of 4,500-5,000m, allows for the reconstruction of annual precipitation in the southern Bolivian Altiplano back to 1290.
• A severe and extensive drought period occurred between 1316 and 1371, representing the longest drought recorded in the past 700 years.
• The transition of Pre-Inca villages from vulnerable valley floors to fortified hilltop sites (Pukaras) coincided with the 1316 drought, suggesting that scarcity of water for irrigation and consumption triggered social conflict.
• Current trends in the Altiplano, including persistent warming since the 1950s and sustained glacier shrinkage, combined with rising water demands from mining, agriculture, and population growth, increase the risk of future water shortages and conflict.

APA

Inter-American Institute for Global Change Research (2012). Tree rings point to drought as trigger of social conflict. https://iai.int/admin/site/sites/default/files/uploads/2014/06/snapshot11_EN.pdf

Chicago

Inter-American Institute for Global Change Research. Tree rings point to drought as trigger of social conflict. 2012. https://iai.int/admin/site/sites/default/files/uploads/2014/06/snapshot11_EN.pdf.

Wikipedia

{{cite report |author=Inter-American Institute for Global Change Research |title=Tree rings point to drought as trigger of social conflict |date=2012 |url=https://iai.int/admin/site/sites/default/files/uploads/2014/06/snapshot11_EN.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{interamericaninstituteforglobalchangeresearch2012tree, author = {{Inter-American Institute for Global Change Research}}, title = {{Tree rings point to drought as trigger of social conflict}}, institution = {Inter-American Institute for Global Change Research}, year = {2012}, url = {https://iai.int/admin/site/sites/default/files/uploads/2014/06/snapshot11_EN.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }