A new academic study has reconstructed roughly 800 years of streamflow history in India’s major rivers, revealing a significant increase in synchronous drought since the mid-19th century. The research suggests that this rise in multiple river basins experiencing drought simultaneously is likely caused by anthropogenic climate change, posing a serious threat to water security for the more than 2 billion people who depend on these river systems.
Reconstructing Centuries of River Flow
Conducted by researchers Chuphal and Mishra, the study overcame the lack of long-term streamflow data by combining several sources. They used decades of streamflow measurements from 45 gauge stations and integrated this with high-resolution temperature and precipitation data. To look farther back in time, they used paleoclimate proxies, specifically tree ring data from the Monsoon Asia Drought Atlas, which provides a record of summer drought conditions in Asia from 1200 to 2012.
The researchers also incorporated historical records of major climate patterns like El Niño and the Indian Ocean Dipole. By combining all this information, they created a reconstruction model that connected historical monsoon failures to periods of low river levels and famine.
A Shift Driven by a Warming Climate
The study’s key finding is a notable increase in the frequency of synchronous drought between 1850 and 2014 compared to preindustrial centuries. This period of increased synchronicity coincides with the rise of industrialization and anthropogenic emissions, leading the researchers to conclude that a warming climate is the likely cause.
The findings align with recent observations that the likelihood of synchronous drought is increasing on the Indian subcontinent as summer monsoons weaken and the Indian Ocean warms. The study serves as a critical warning that if current trends continue, future synchronous droughts could severely disrupt water resources, agriculture, and the livelihoods of communities throughout India.