MOSCOW, November 27. . Paleoclimatologists from India and the United States have discovered fossil evidence in the Indus Valley that about 3.4-4.4 thousand years ago, its tributaries periodically dried up or even temporarily stopped flowing during a series of severe droughts, at least one of which lasted more than 100 years. These events marked the end of the Indus civilization, scientists wrote in an article published in the scientific journal Earth & Environment Communications.
“Previously, discovering the cause of the disappearance of the Indus civilization was hindered by the lack of a large number of paleoclimate indicators. We have combined all known information of this type and the results of climate simulations, allowing us to identify a series of prolonged and severe droughts that periodically affected the Indus valley from 3.4 – 4.4 thousand years ago,” the study said.
This conclusion was made by a team of Indian and American paleoclimatologists led by Professor Balaji Rajagopalan of Colorado State University (USA) when studying the history of climate fluctuations in the Indus River Valley during the decline of the Indus civilization. It is one of the oldest civilizations on Earth along with ancient Egypt and Mesopotamia.
According to the current understanding of historians and archaeologists, the Indus civilization appeared about 5 thousand years ago in the Indus River valley on the border between modern India and Pakistan and reached its peak in 2200 – 1900 BC. Over the following centuries, it rapidly declined and disappeared without a trace, which scientists attribute to climate changes in the region, which became much drier at the beginning of the second millennium BC.
Climatic history of the collapse of the Indus civilization
To explore the nature of these changes, the researchers analyzed changes in the isotopic composition of stalactites in India's Sakhya and Mavmluh caves, reflecting fluctuations in rainfall 3-5 thousand years ago, and combined them with the results of computer models of the climate of the Indus Valley during this period. Based on these calculations, scientists determined how much water flowed into the tributaries of the Indus and how the depth of these rivers changed during different periods.
These calculations show that at the beginning of the era of decline of the Indus civilization, the overall rainfall in the Indus Valley decreased by 10-20%, and the average temperature on its territory increased by 0.5 degrees Celsius. According to scientists, the reason for this was the weakening of the monsoon, the signs of which were previously identified by other scientific groups. It turns out that the Indus Valley experienced a series of four long droughts, each covering 65-91% of the valley and lasting more than 85 years.
The last drought, which lasted 113 years, began about 3.53 thousand years ago and ended 3.4 thousand years ago, coinciding with the final decline of the Indus civilization and the collapse of all its major cities. Scientists concluded that this showed that this ancient civilization fell victim to a series of prolonged droughts, forcing its last representatives to leave the Indus Valley and move to more habitable regions of Hindustan.
