Climate change likely caused demise of Indus Valley civilisation: Study

WASHINGTON DC: A shift in temperatures and weather patterns over the Indus valley starting about 2500 BC may have driven the Harappans to resettle far away from the floodplains of the Indus, a study has found.

More than 4,000 years ago, the Harappa culture thrived in the Indus River Valley of what is now modern Pakistan and northwestern India, said researchers from the Woods Hole Oceanographic Institution (WHOI) in the US.

The Harappans built sophisticated cities, invented sewage systems that predated ancient Rome's, and engaged in long-distance trade with settlements in Mesopotamia, they said.

Yet by 1800 BC, this advanced culture had abandoned their cities, moving instead to smaller villages in the Himalayan foothills.

Beginning in roughly 2500 BC, a shift in temperatures and weather patterns over the Indus valley caused summer monsoon rains to gradually dry up, making agriculture difficult or impossible near Harappan cities, said Liviu Giosan, a geologist at WHOI.

"Although fickle summer monsoons made agriculture difficult along the Indus, up in the foothills, moisture and rain would come more regularly," said Giosan, lead author of the study published in the journal Climate of the Past.

"As winter storms from the Mediterranean hit the Himalayas, they created rain on the Pakistan side, and fed little streams there," said Glosan.