Researchers have been looking for a definite answer about how the Indus Valley Civilization came to an end and a new research by the University of Cambridge and Banaras Hindu University sheds light on how exactly the glorious period of 3500 to 1800 BC spreading over today's India and Pakistan collapsed.
The outcome of the research indicates that the abrupt weakening of the monsoon affected northwest India 4,100 years ago which led to extinction of the civilization. “The major source of water here throughout the Holocene is likely to have been the summer monsoon. But we have observed that there was an abrupt change, when the amount of evaporation from the lake exceeded the rainfall - indicative of a drought," said Yama Dixit, a Gates Scholar who collected Melanoides tuberculata snail shells from the sediments of the ancient lake Kotla Dahar in Haryana.
Dixit is part of a project led by the University of Cambridge and Banaras Hindu University which has been funded by the British Council UK-India Education and Research Initiative to investigate the archaeology, river systems and climate of northwest India using a combination of archaeology and geo-science.
Analyzing the oxygen isotopes in the shells, scientists are now able to tell how much rain fell in the lake thousands of years ago. The results shed light on a mystery surrounding why the major cities of the period were abandoned. Climate change had been suggested as a possible reason for this transformation before but until now there was no direct evidence.
"We think that we now have a really strong indication that a major climate event occurred in the area where a large number of Indus settlements were situated. We can now confirm widespread weakening of the Indian summer monsoon across large parts of India 4,100 years ago," said David Hodell from Cambridge's department of earth sciences.
The latest findings in the research now links the decline of the Indus cities to a documented global scale climate event and its impact on the Old Kingdom in Egypt, the Early Bronze Age civilizations of Greece and Crete and the Akkadian Empire in Mesopotamia whose decline has previously been linked to abrupt climate change.
Photograph by Grjatoi
