60-year drought ended ancient Assyrian empire

Bas-relief in the British Museum of an Assyrian lion hunt. Image: By Lawson G Stone, via Wikimedia Commons

It took only a 60-year drought to lay low one of the first superpowers. It crumbled when harvests withered over two millennia ago.

LONDON, 25 November, 2019 − One of the great ancient empires, the neo-Assyrian world of what is now northern Iraq, flourished in years of plentiful rain, but buckled and collapsed when beset by a 60-year drought.

The biblical city of Nineveh fell in 612 BC, weakened by climate change, never to be occupied again. Chroniclers blamed political instability, the might of Babylon, and the invasions of Medes and Persians.

But climate scientists who have reconstructed the evidence of annual weather records have set the record straight: like the rings of a tree or the sediments in a lake, the isotope records in stalagmites in the floor of the Kuna Ba cave tell a story of a mega-drought that underlay the collapse of one of ancient history’s earliest superpowers.

Stalagmites or speleothems are built up by the steady drip of water through rock and onto the floor of a cave. The scientists report in the journal Science Advances that they used carbon and oxygen isotopes in the layers of stone to reconstruct the climate throughout a 3800-year sequence of rainfall patterns.

The measures of uranium and thorium trapped in the same speleothems provided precise dates for the entire sequence, and these could then be checked against surviving records from an empire that at its height, under King Sennacherib, extended into parts of what are now Turkey, Iran, Syria, Jordan, Lebanon, Israel and Egypt.

“These societies experienced climatic changes that were of such magnitude they could not simply adapt to them”

“We now know that the Assyrian droughts started decades earlier than we had previously thought, and also that the period prior to the onset of drought was one of the wettest in the entire roughly 3800-year sequence.

“It changes some of the other hypotheses we have made”, said Adam Schneider, of the University of Colorado at Boulder, who first proposed a climate link to imperial collapse in 2014.

“For example: King Sennacherib, who ruled from 705 to 681 BC, was well-known for building massive canals and other structures. In our earlier work on the question of drought in ancient Assyria, I and my colleague Dr. Selim Adali had initially viewed him as a short-sighted ruler who had pursued short-term political goals at the expense of long-term drought resilience, and set in motion a catastrophic chain of events as a result.

“But with this new data, we now think that Sennacherib probably was already experiencing drought when he was king, and in fact he may well have been trying to do something about the environmental calamity during that time.”

And a co-author, Harvey Weiss of Yale University, said : “Now we have a historical and environmental dynamic between north and south and between rain-fed agriculture and irrigation-fed agriculture through which we can understand the historical process of how the Babylonians were able to defeat the Assyrians.”

New theory

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

The climate change theory of history is relatively new, but has already been used to provide new explanations for the collapse of the Bronze Age empire in the Mediterranean 3,000 years ago, the downfall of the Ptolemaic dynasty in Egypt, the rise of Genghis Khan’s nomadic hordes  and the fall of the Mayan civilisation in the Americas.

There have been arguments that contemporary conflict can be matched to climate stress in many parts of the modern world.

“The French Revolution is one example. In the two years prior to the French Revolution poor weather led to a series of bad harvests, which alongside other factors helped cause the price of bread to skyrocket, especially in Paris,” said Professor Schneider.

“The question is not ‘Did climate have an impact?’ It’s ‘How, why and how important was climate alongside the other factors?’” − Climate News Network