How climate change destroyed one of the world's largest civilizations
Located in present-day India and Pakistan, the Harappan civilization fell victim to shifting monsoon patterns, a new study has found.
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Eventually, these monsoon-based rivers held too little water and dried, making them unfavorable for civilization.Skip to next paragraph
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"The Harappans were an enterprising people taking advantage of a window of opportunity — a kind of "Goldilocks civilization," Giosan said.
Eventually, over the course of centuries, Harappans apparently fled along an escape route to the east toward the Ganges basin, where monsoon rains remained reliable.
"We can envision that this eastern shift involved a change to more localized forms of economy — smaller communities supported by local rain-fed farming and dwindling streams," Fuller said. "This may have produced smaller surpluses, and would not have supported large cities, but would have been reliable."
This change would have spelled disaster for the cities of the Indus, which were built on the large surpluses seen during the earlier, wetter era. The dispersal of the population to the east would have meant there was no longer a concentrated workforce to support urbanism.
"Cities collapsed, but smaller agricultural communities were sustainable and flourished," Fuller said. "Many of the urban arts, such as writing, faded away, but agriculture continued and actually diversified."
These findings could help guide future archaeological explorations of the Indus civilization. Researchers can now better guess which settlements might have been more significant, based on their relationships with rivers, Giosan said.
It remains uncertain how monsoons will react to modern climate change. "If we take the devastating floods that caused the largest humanitarian disaster in Pakistan's history as a sign of increased monsoon activity, than this doesn't bode well for the region," Giosan said. "The region has the largest irrigation scheme in the world, and all those dams and channels would become obsolete in the face of the large floods an increased monsoon would bring."
The scientists detailed their findings online May 28 in the journal Proceedings of the National Academy of Sciences.
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