Judea (701 bce). Detail from bas-relief removed from sennacherib's palace without rival

Did drought fell the great Assyrian Empire?

Two centuries of dominance by the Neo-Assyrian Empire might have been undone by a 60-year megadrought, US researchers say.

Their study of precipitation records suggests that the once powerful state, which extended from Iran to Egypt, was left so weakened that by 612 BCE its capital Nineveh was relatively easy pickings for the Babylonians from the south and the Medes from the east.

Some archaeologists and historians call it the “mother of all catastrophes”; many have long wondered how two small armies were able to completely destroy what was then the largest city in the world, without any reoccupation.

Neither excavation, nor field study, nor old documents has been able to provide an answer.

Now a team of researchers led by Ashish Sinha from California State University, using archival and archaeological data provided by Harvey Weiss from Yale University, has come to the conclusion that it was all about the weather. 

Their findings are reported in the journal Science Advances.

Assyria was an agrarian society dependent on seasonal precipitation for cereal agriculture. To its south, the Babylonians relied on irrigation agriculture, so their resources, government, and society were not affected by the prolonged drought, Weiss says.

Sinha’s team analysed stalagmites retrieved from Kuna Ba cave in northeast Iraq.  Formed by the deposit of minerals from water, these provided a history of climate through the oxygen and uranium isotope ratios of infiltrating water that are preserved in their layers. 

With Weiss, they then synchronised the findings with archaeological and cuneiform (written) records and were able to document the first paleoclimate data for the megadrought that affected the Assyrian heartland at the time of the empire’s collapse.

The research also revealed that a high-rainfall period preceded the drought, supporting the empire’s growth and expansion.

Weiss says he was able to piece together how the megadrought data were synchronous with Assyria’s cessation of long-distance military campaigns and the construction of irrigation canals that were similar to its southern neighbours – but restricted in their agricultural extent. 

Other texts noted that the Assyrians were worrying about their alliances with distant places, while also fearing internal intrigue, he notes.

“This fits into a historical pattern that is not only structured through time and space, but a time and space that is filled with environmental change,” says Weiss. “These societies experienced climatic changes that were of such magnitude they could not simply adapt to them.”