For almost two millennia, the Assyrian Empire dominated the ancient Near East. But some 2,700 years ago, it essentially imploded, morphing from a powerful kingdom between Babylon and the Hittite lands to a vassal state controlled by foreign rulers.

The Assyrians were brought low by a combination of overpopulation and drought, says a Turkish-American team of scientists. Their conclusions have worrying implications for the modern Near East, and Israel.

Both conditions exist in the region today: Israel is considered one of the most crowded countries in the world, and climate change is expected to make this arid region even drier.

Adam Schneider of the University of California, San Diego and Selim Adal of Koc University in Istanbul, explain their revelation. “As far as we know, ours is the first study to put forward the hypothesis that climate change – specifically drought – helped to destroy the Assyrian Empire,” states Schneider, a doctoral candidate in anthropology at U.C. San Diego and the first author on the paper in the journal Climatic Change, evocatively titled "No harvest was reaped".

The breakthrough came from correlating the latest climate change data with a letter to the Assyrian king, written on a clay tablet by a court astrologer who reports, inter alia, that “no harvest was reaped” in 657 BCE.

A time of drought

Scholars had assumed that the Neo-Assyrian Empire suddenly began to decline in the 7th century BC due to war. They note the destruction of the Assyrian capital, Nineveh, by a coalition of Babylonian and Median forces in 612 BC, write the researchers in their paper.

But it didn't make sense to them that a force as powerful as the Assyrians "and the largest empire the Old World had ever seen up to that time" could just collapse so fast. They believe that intense drought and with over-population combined in fatal form, which was taken advantage of by Assyria's enemies.

Paleoclimatic records buttress up the courtier’s woeful letter. Moreover, analysis of regional weather patterns in what had been the Assyrian kingdom - now northern Iraq and Syria, which are under ISIS control - suggests that the drought was not a singular event, but protracted, lasting years, they say.

And then there was the strain of overpopulation, notably in Nineveh, where the population had been deliberately beefed up by King Sennacherib – a name well known in ancient Israel, not least for flattening ancient Judah in 701 BCE to punish the rebellious vassal king, Hezekiah. The crowding substantially reduced the drought resilience of the region, the scientists write.

Yes, quake, o ye policy-makers: Now, 2,700 years later, Israel is among the most overpopulated countries in the world, with Kuwait and Singapore, according to the Overpopulation Index ("overpopulated" means these countries consume more resources than they produce and are dependent on other countries). And one prediction of climate change scientists is that the entire near eastern region and north Africa will just get drier.

Within five years of the no-harvest report, Assyria was wracked by one civil war after another. Then joint Babylonian and Median forces attacked the weakened empire, and razed Nineveh in 612 BC.

“We’re not saying that the Assyrians suddenly starved to death or were forced to wander off into the desert en masse, abandoning their cities,” Schneider said in a statement. “Rather, we’re saying that drought and overpopulation affected the economy and destabilized the political system to a point where the empire couldn’t withstand unrest and the onslaught of other peoples.”

Flash-forward: Disaster looming

With all due respect to desalination technology, the downfall of ancient Assyria has ominous lessons for this day. Schneider and Adal see striking parallels between the catastrophe nearly three millennia ago and the drought and war in the region today, much of which is controlled by ISIS.

But why stop there. Schneider sees the story of Nineveh as a warning for southern California too. Though Americans weren’t forcibly relocated to a later-day Nineveh at the emperor's whim, by the criteria of sustainability, southern California is overpopulated.

The ancient Assyrians may have been a technological superpower at the time, but they couldn't have known their empire-building and forced relocations were dooming them to death by environmental abuse. We modern humans have no excuse, they write: "We also possess the additional benefit of hindsight, which allows us to piece together from the past what can go wrong if we choose not to enact policies that promote longer-term sustainability.”