The Great Pyramids of Egypt
Sun-smothering dirt thrown up by volcanoes of more than 2000 years ago, starving the headwaters feeding the river Nile and hastened the downfall of ancient Egypt, the last kingdom, researchers claim.
Eruptions in the 3rd and the 1st century BC — including one of the largest blasts in the last 2500 years, together with crop failures, large-scale uprisings and the withdrawal of the Egyptian armies from the battlefield, they reported in the journal Nature Communications.
Until now, researchers had difficulty finding an explanation for these events.
Volcanic eruptions may have had a central role in the final collapse of the Ptolemaic dynasty,” the magazine stated in an overview.
The findings, the authors say, also point to the risk of climate-engineering schemes that would combat global warming by injecting billions of small particles in the stratosphere like a volcano to block some of the rays of the sun.
Even if so-called solar radiation management reduces the temperature of the earth a notch or two, may inadvertently lead to major disruptions in precipitation patterns.
“Ptolemaic the vulnerability of volcanic eruptions provides a warning for all monsoon-dependent agricultural regions”, which are today 70 per cent of the world’s population, the authors wrote.
The Ptolemaic empire began in 305BC shortly after the death of Alexander the Great and ended in 30BC with the suicide of Cleopatra. After that, the region became a Roman province.
The kingdom usually flourished, fed by the silt-rich river Nile overflowing its banks in the summer on a distant network of grain fields. An ingenious system of channels and dams stored water to the river, and disappeared in September.
“If the tide was good, the Nile Valley is one of the most fertile places in the ancient world,” said Francis Ludlow, a climate history at Trinity College in Dublin and co-author of the study.
But in some years, the river failed to rise, and the problems followed. Why this happened is not known.
Drawing from climate models, the Greenland ice cores, and ancient Egyptian writings, researchers, under the leadership of Joseph Manning of the University of Yale explained to a story that appeared to be an unmistakable link with large volcanic eruptions around the world.
In 245BC, for example, the ruler of Ptolemy III, suddenly and inexplicably, abandoned a successful military campaign against his arch nemesis, the Seleucid Empire, centered in present day Syria and Iraq.
“This about-face changed everything about the Near East, the history,” Manning said.
Historical records also pointed to the simultaneous food shortages as a result of insufficient flooding of the Nile, as well as violent uprisings in the Ptolemaic empire that stretched across the northeast of Africa and parts of the Middle East.
A similar confluence of social unrest, disease and famine hit the empire in its last two decades.
Both periods of unrest, the researchers found, along with large volcanic eruptions.
Of more recent records, scientists know that the tens of millions of tonnes of sulphur particles emitted in the upper layers of the atmosphere from a large eruption can avoid the monsoon to move far enough to the north of the equator, to thoroughly enjoy the Ethiopian highlands, the headwaters of the Nile.
This happened in 939 when Eldgja, Iceland, blew his top, and again in 1783-84, when the icelandic Laki erupted.
The Islamic Nilometer, a log of the Nile water level since 622, showed a positive impact on the river.
“The volcanic eruptions, is not caused by this (social) unrest on their own,” Ludlow said.
“But they are likely to fuel added to the existing economic, political and ethnic tensions.”
This story was previously published in the news.com.au.