Scottish geologists help solve mystery of lost civilisation

By FRANK URQUHART
Published on 01/06/2012 00:00

A TEAM of international researchers, led by Scottish geologists, claim to have finally solved the reason behind the mysterious decline and fall of one of the world’s greatest, but least known ancient civilisations. The culprit, they say, was climate change.

The Harappan Civilisation, which flourished 4,000 years ago, stretched over almost over 380,000 square miles on the plains of the Indus River – from the Arabian Sea to the Ganges.

Theories advanced for its dramatic collapse in the past have ranged from an invasion by rampaging Aryan hordes, to a change in the course of the Indus.

But a new study, led by researchers at Aberdeen University, has found climate change was the key factor in the collapse of the mighty Harappan empire around 2000 BC.

The Harappan people were forced to flee their cities on the once fertile plains and head east in the face of declining monsoon rains that stopped feeding the river systems on which their crops depended.

The international team of scientists was led by Peter Clift when he was a professor in the Department of Geology and Petroleum Geology at Aberdeen University. He is now based at Louisiana State University.

Prof Clift and his team conducted research on the ground in Pakistan, between 2003 and 2008, and also combined satellite photos and topographic data to produce a compelling picture of 10,000 years of dramatic changes in the landscape.

The new study suggests that a decline in monsoon rains led to weakened river dynamics, and played a critical role in the collapse of the Harappan culture, which relied on river floods to fuel their agricultural system.

Prof Clift explained: “The Harappa were able to thrive because they exploited an ecological niche that disappeared as the climate dried about 4,000 years ago. The story of the Harappan gives us pause for thought concerning the effects of future climate change in this heavily populated region.”

Liviu Giosan, lead author of the study, added: “The Harappans were an enterprising people taking advantage of a window of opportunity – a kind of ‘Goldilocks civilisation.’ ”

“As monsoon drying subdued devastating floods, the land nearby the rivers – still fed with water and rich silt – was just right for agriculture.

“But continued aridification closed this favourable window.”