Overview
- The paper, published in Communications Earth & Environment, identifies four prolonged droughts between about 4,450 and 3,400 years ago, each lasting more than 85 years and covering 65%–91% of the region.
- Authors find a final drought of roughly 113 years from 3,531 to 3,418 years ago that aligns with archaeological evidence of widespread deurbanization.
- Climate reconstructions indicate regional warming of about 0.5°C and a 10%–20% drop in average annual rainfall during the study period.
- Settlement patterns shifted toward the Indus River from around 4,500 years ago, followed by moves toward the Himalayan foothills and the Ganga plain as drying persisted.
- The study suggests natural variability such as El Niño and the Atlantic Multidecadal Oscillation, amplified by vegetation loss and dust, may have driven the drying, with commentators urging future work to include evapotranspiration and to inform modern water management.