Harappan Civilisation or Indus Valley Civilisation has been caught the fancy of the world for its urban planning, houses made of baked bricks, excellent drainage and water supply systems and clusters of large non-residential buildings.
How the civilisation demised is something which is still not known and various theories about its downfall keep getting prominence now and again. That the script of the civilisation has not still been deciphered adds more to the enigma of one of the world's most urban civilisation of the Bronze Age.
Recently after a study conducted by paleoclimatologists of isotope data from the sediment of civilisation's ancient lake, it has been suggested that the civilisation disappeared due to unfavourable climate change.
A paleoclimatologist Yama Dixit at the University of Cambridge UK and her colleagues examined sediments from Kotla Dahar. The ancient lake is situated near the north-eastern border of the Indus Valley Civilisation area in Haryana.
This lake still flood during certain seasons. The team after the study of sediment layers using radiocarbon dating of organic matter suggested that between 4,200 and 4,000 years ago precipitation decreased dramatically.
As per the research team the regular monsoon rains which are a must for South Asia region for people to flourish stopped for some 200 years. This could have forced Harappans to gradually abandon cities.
Another study was recently done by a team of paleoclimatologist led by Sushma Prasad from German Research Center for Geoscience in Potsdam. The research was done on a sediment core from Lonar Lake which is situated in central India. The research team found that in that area drought began around 4,600 years ago.
However, both the researches come to same conclusion that it was by about 4,200 years ago that the drought became very intense. The German research team also concluded that lack of rain spelled the end of the Indus Valley Civilisation.
One researcher David Hodell, who was a co-author of the study and a paleoclimatologist also at the University of Cambridge said that Happan Civilisation was an example like many other examples as to how the ancient societies had to face the climate changes. He further added that this can be a lesson for us as we too will have to face such anthropogenic climate change.
Anil Gupta who is the director of the Wadia Institute of Himalayan Geology in Dehradun said that these researches fill the gap in the geographic record of droughts faced by the ancient world. However he added that this research doesn't tell us as to what caused this climate change around 4,100 years ago. He added that no major change in the North Atlantic or in the solar activity happened at that time.
Such researches are very important as a recent case study done in India and three other countries (France, the United States and China) says that there will be no drinking water by 2040 if consumption of water continues at the same pace as it is now.