(CN) – Roughly 2,600 years ago, the largest Mesopotamian empire fell due to political unrest, civil war, overpopulation and – according to a new study – climate change.
The Neo-Assyrian Empire included modern-day Iraq and Syria and at its height also stretched from northern Africa to the Persian Gulf and into what is now Turkey. In the approximately 300 years of its existence, the Iron Age empire saw the reign of multiple dynasties, plagues and conflicts with the Babylonian, Persian and many other neighboring empires.
And in its final 60 years, it saw the effects of multidecade droughts.
According to a study published on Wednesday in the journal Science Advances, the Neo-Assyrian Empire’s rise and fall was bookended by rain.
The empire’s expansive borders increased the need for a stable supply of food and water for urban centers and the Assyrian cavalry, according to the study’s authors. Control over water was also politically sensitive, which played into propaganda from Assyrian kings as the construction of canals and reservoirs preceded the move of the capital circa 879 B.C.
The study’s lead author – Earth and climate sciences professor Ashish Sinha from California State University, Dominguez Hills – says two stalagmites found in northern Iraq gave researchers a record of rainfall over the last 4,000 years.
Researchers studied the oxygen and carbon isotopic data from the sample, which showed from 850 to 740 B.C. – during the peak of the empire’s reign – rainfall levels were at their highest in centuries. Precipitation levels during the cool season were 15% to 30% higher than during the modern era, but that changed during a 7th century megadrought, according to the study’s authors. The drought lasted for years, and the data suggest that, if it continued for more than a century, it would have been the worst episode of drought in the region in the last four millennia.
The drought set off a debilitating domino effect, stifling agriculture, causing civil unrest amid a shortage of food and water, and stoking political upheaval. Uprising then gave way to civil wars as the empire’s enemies closed in from multiple fronts. Once the mightiest of nations, the fall of Assyria began around 627 B.C. with the empire stretched thin.
By 612 B.C., the capital had changed multiple times until final settling in Harran near the Tigris River. That city was sacked after a siege by the Babylonians and Medes, eventually falling for good in 605 B.C.