Evidence of other empire toppling droughts lay buried in the sediments of the Nile River until it was dug up by a University of Pennsylvania doctoral student who now works for the USGS. The results were published in Geology.
Approximately 5,000 years ago, another drought may have hastened the demise of the kingdom of Uruk in what is now Iraq.
In an echo of modern times, Syria suffered during a drought 3,000 years ago. The Babylonians too felt the effects of famine from that drought. On the coast of the eastern Mediterranean, the Ugarit kingdom fell at that time.
"Humans have a long history of having to deal with climate change," said study author Christopher Bernhardt. "Along with other research, this study geologically reveals that the evolution of societies is sometimes tied to climate variability at all scales – whether decadal or millennial."
Bernhardt drilled into sediments laid down in the Nile Delta to get a record of what plants were growing, or burning, at different times in history. When pollen from water-loving plants decreased, he knew that the actual abundance of vegetation in ancient times had also likely decreased. An increase in charcoal meant that fire was ravaging the land of the pharaohs. A heavy layer of charcoal and thin layer of pollen was a good sign that a massive drought may have occurred.
The pyramids at Giza (Ricardo Liberato, Wikimedia Commons)