Image Credit: Saqib Qayyum, via Wikimedia Commons

Droughts That Lasted Decades Doomed the Indus Civilization

A new study has revealed that a sequence of severe, decades-long droughts played a decisive role in the collapse of the Indus Valley Civilization — one of the world’s earliest urban societies.
The civilization, also known as the Harappan culture, flourished between 5,000 and 3,500 years ago across what is now India and Pakistan. Its people built planned cities such as Harappa and Mohenjo Daro, developed advanced water systems and long-distance trade, and created a script that remains undeciphered.
Why this powerful civilization declined has long been debated. The new research, published in Communications Earth & Environment, points to extreme climate stress as a major driver. According to the team, successive droughts lasting more than 85 years each gradually dried up rivers, weakened the monsoon and forced populations to relocate.
A major century-long drought beginning around 3,500 years ago coincided with the abandonment of large cities and a widespread shift toward smaller rural settlements.
To reach their conclusions, scientists analyzed three independent global climate simulations showing rainfall and temperature from 5,000 to 3,000 years ago. All three revealed the same pattern: persistent decline in precipitation, multi-century droughts and major monsoon weakening.
Researchers then fed this data into a hydrological model to reconstruct ancient rivers and water sources, comparing the results with archaeological evidence showing how settlements moved over time. Their findings matched earlier cave and lake studies that also pointed to prolonged drought.
Experts who reviewed the research praised the modeling work. They noted that understanding how ancient societies responded to shifting climate conditions offers important insights into how environmental stress can reshape human history.

Published on: 27-11-2025

Edited by: Abdulmnam Samakie

Source: Live Science