23 January 2020
Climate change could be associated with collapse of Assyrian Empire
Published online 18 November 2019
A newly uncovered record of climate change provides a better picture of the factors that influenced both the rise and fall of the Neo-Assyrian Empire.
Precisely dated records of rainfall obtained by analysing oxygen and carbon isotopic data from cave formations in northern Iraq suggest that climate change played a role in shaping the rise and abrupt fall of the Neo-Assyrian Empire. The empire was centred in northern Iraq and extended from Iran to Egypt between 912 and 609 BCE, making it the largest empire of its time.
“Our data uncovered a handful of anomalously wet periods in the context of the last 4,000 years,” says Ashish Sinha, an earth and climate scientist at California State University. The most significant of these unusually wet conditions occurred between 2,700 and 2,900 years ago, when the Neo-Assyrian Empire was at its peak. “We were surprised to see the strong connection between climate and the rise of the empire,” he says.
The two-centuries-long interval would have been favourable for rain-fed agriculture and key to strengthening the Assyrians’ agrarian-centric economy.
“The entire machinery of the Neo-Assyrian Empire was funded in large part from revenues generated from agriculture, which was overly reliant on rain, unlike the Babylonians in the south, who were using the irrigation method,” Sinha explains.
He points out that the empire’s unsustainable growth may have “exceeded the natural carrying capacity of the land once the pendulum of climate change swung the other way.”
And swing it did — the study revealed that decades-long droughts subsequently occurred in the seventh century BCE.
This megadrought would have led to repeated crop failures, exacerbating political unrest, crippling the economy and empowering rival states. Historians concur that the Assyrian Empire ultimately fell to a coalition of forces including the Babylonians, Medes and Scythians.
While the megadrought likely triggered a rapid economic decline, Sinha asserts that “the wheel of Assyrian collapse was set in motion” during the wet climate period, when the empire may have become “too big and unwieldy”. The underlying effects of climate change, he reasons, began centuries before the empire’s collapse.
Important parallels can be drawn between past and modern droughts. For example, the devastating drought of 2007–2008 in northern Iraq and Syria, the most severe in decades, hit wheat and barley production across the region. “Our research suggests that these modern droughts offer a glimpse of what Assyrians endured during the mid-seventh century BCE,” Sinha says.
“Much of the Middle East and the eastern Mediterranean region is already in the grips of a century-long drying trend,” he says, which is clearly “not good news for a politically volatile and water-stressed region.”
Sinha, A. et al. Role of climate in the rise and fall of the Neo-Assyrian Empire. Sci. Adv. 5, eaax6656 (2019).