As the world heads towards dangerous global warming — far beyond the scientifically safe limit of 2 degree C above pre-industrial temperatures (1850–1900) — the dusty ruins of the Indus Valley civilisation (IVC) serve as a stark warning of what could await humanity if climate change is not reversed.
The decline of IVC around 1500 BCE has long puzzled scholars, but most agree that climate change played a central role. Now, a team of researchers from the Indian Institute of Technology, Gandhinagar, and two US universities provides fresh evidence linking the collapse to two prolonged droughts — one lasting 85 years, and the second, 900 years later, that lasted 119 years.
By analysing lake beds, cave mineral deposits, and climate simulations, the study identified a sequence of severe, intensifying droughts beginning around 2440 BCE, during IVC’s “mature period” (2600–1900 BCE). The team pinpointed four major drought events, each lasting over 85 years, with the third drought (3826–3663 BCE) stretching into 163 years, reducing rainfall by 13 per cent, and affecting 91 per cent of the region.
These droughts were triggered by El Niño events in the Pacific and Indian Ocean, which weakened the monsoon, while cooler North Atlantic waters further diverted rainfall. Local factors such as dust and land-use changes amplified the effects. The civilisation gradually collapsed, with cities abandoned and populations dispersing.
Today, human-made global warming threatens to repeat history — except, this time, unlike IVC, humanity may have nowhere to migrate.
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Published on December 1, 2025