From around 1650 to 1200 B.C.E., the Hittite Empire ruled over much of Anatolia in modern Turkey, as well as northern Syria. They battled Egyptians for control of Canaan, developed long-distance trade networks and farmed with advanced irrigation systems. But then, the state suddenly collapsed. Its capital city was abandoned, and its leaders may have fled the palace.
Researchers have been grasping at explanations for the empire’s downfall for centuries, suggesting volcanic eruptions, earthquakes, invasions, political and economic failures and diseases, writes National Geographic’s Tom Metcalfe.
But more recently, archaeologists have considered that climate may have played a role. Previous evidence suggests the region where the Hittites reigned might have become drier and cooler between the 13th and 10th centuries B.C.E. In a new study published last week in the journal Nature, scientists use ancient tree rings to show that the area experienced three extremely dry years around 1198 to 1196 B.C.E., right around the empire’s collapse. They propose that this particularly intense period of drought could have contributed to the end of the Hittites.
“One year of drought is a problem. Two years—it’s a crisis. By three years in a row, perhaps it’s actually more than a crisis,” Sturt Manning, first author of the new study and an archaeologist at Cornell University, tells the Washington Post’s Sarah Kaplan. “Seeing that back-to-back-to-back failure—that’s probably what overthrows a major state.”
Though drought alone may not have been enough to topple the Hittites, such a long-lasting dry period could have destabilized the empire, leaving it more vulnerable to other threats such as an invasion or famine and unrest, the researchers suggest. “We’re not saying the climate solely caused the collapse of the Hittites,” Manning tells Nature News’ Miryam Naddaf. But it could have primed them for their demise.
Tree rings provide snapshots of an area’s climate history. The researchers looked at timber from juniper trees recovered from an archaeological excavation in central Anatolia. The logs had been buried for almost 3,000 years and were from a burial mound associated with King Midas, located about 50 miles southwest of Ankara, Turkey, per National Geographic.
Twenty-three samples from around 18 different trees contained rings spanning the years 1775 to 748 B.C.E. The width of tree rings can indicate the amount of rainfall an area received—trees grow less when it’s drier, and thus their rings are narrower during drier years. The researchers found that the rings of the junipers grew slimmer in the five decades before the Hittites fell, per the Post.
But the period from 1198 to 1196 B.C.E. was particularly dry—among the driest times the area had experienced in more than 600 years, Manning told Inside Climate News’ Kristoffer Tigue.
Carbon isotopes in the wood, an indicator of the moisture available to trees, supported their finding. The isotopes indicated likely dry to very dry conditions between 1232 and 1192 B.C.E., with drier spikes from 1222 to 1221 B.C.E. and around 1195 B.C.E.—a peak of dryness that nearly coincided with the fall of the empire.
“There was likely near-complete crop failure for three consecutive years,” Brita Lorentzen, a co-author of the paper and an anthropologist at the University of Georgia and Cornell’s Tree Ring Laboratory, tells Reuters’ Will Dunham. “This would have led to a collapse of the tax base, mass desertion of the large Hittite military and likely a mass movement of people seeking survival. The Hittites were also challenged by not having a port or other easy avenues to move food into the area.”
An intense dry period could have put significant strain on the Hittite Empire. “A short, sharp drought would be enough to topple a very centralized state based heavily on grain and the gathering in and distribution of agricultural goods,” Alan Greaves, an archaeologist at the University of Liverpool in England who wasn’t involved in the study, tells New Scientist’s Clare Wilson.
Harvey Weiss, an archaeologist at Yale University who did not contribute to the research, tells the Post that a longer-term drought likely played a bigger role than a three-year event. “Two or three years of drought are not much, but an abrupt mega-drought with high magnitude creates cascading effects,” he tells Nature News.