A new study of fossilized coral reefs off the coast of Tamil Nadu has provided the first high-resolution climate record of the 10th to 13th centuries CE, coinciding with the peak of the Chola Empire. The research reveals a period of extreme monsoon volatility, characterized by decade-long droughts followed by intense flooding, which forced the empire to develop its famous monumental irrigation tanks and sophisticated water-management systems.
Isotopic data from the corals suggests that the Chola's expansionist naval policies may have been partly driven by the need to secure maritime trade routes and food supplies during periods of agricultural failure at home. This breakthrough in environmental history demonstrates how climatic pressure acted as a catalyst for technological and political innovation in medieval South India. The findings are being used to create new models for climate resilience in the face of modern monsoon shifts.