bodyType

customContents

entityId

entityUuid

articlePageQuery

filter

article

articleBaseAdvertisingInfoArticle

articleListArticle

articleSeoArticle

hooksArticleAcknowledgementGateOverlayArticle

hooksTrackPageViewArticle

hooksContentInterestArticle

articleLinkingDataContent

hooksAmpRedirectArticle

articleSchemaContent

liveArticle

advertZone

sentiment

contentLock

topics

types

sections

paywallTypes

createdDate

publishedDate

urlAlias

moreOnThisArticles

sponsorType

commentCount

authorLocations

authors

corrections

displaySlideShow

multimediaEmbed

printHeadline

seriesContainer

articleSpeeches

socialHeadline

headline

images

flag

firstTopic

glossary

flattenTypeIds

image

relatedLinks

relatedNewsletters

__typename

sponsor

pdfFiles

seriesReverseOrder

series

disableOffPlatformContent

published

updatedDate

summary

subHeadline

body

keywords

readingTime

customTimezone

liveContents

Associated Press

Did violent volcanoes in Russia, Greenland and Alaska affect the lives of ancient Egyptians?
It may sound improbable, but according to a new study, the answer is yes.
In a paper published on Tuesday in Nature Communications, a team of researchers shows that explosive volcanic eruptions in high northern latitudes of the globe can impact the Nile watershed, causing the flow of one of the world’s mightiest rivers to slow.
This in turn could keep the lower Nile from flooding in the late summer months – a regular occurrence on which ancient Egyptians relied to irrigate their crops.
No Nile flooding meant no irrigation, which meant a bad year in the fields, low food supplies and ultimately, researchers say, civic unrest.
“It’s a bizarre concept that Alaskan volcanoes were screwing up the Nile, but in fact, that’s what happened,” said Joseph Manning, a historian at Yale University who worked on the study.

Manning said the idea to compare geological evidence of volcanoes with records kept by the ancient Egyptians occurred to him about two years ago.
He was at a dinner with geographer Francis Ludlow, now at Trinity College in Dublin, who had contributed to a seminal study that redated volcanic eruptions and looked at how they may have impacted the climate, and history, at the time.
Around their third glass of wine, Manning asked Ludlow whether he had any data on volcanoes that erupted from 305 to 30BC – the centuries that the powerful Ptolemaic dynasty ruled Egypt, and Manning’s area of expertise.
When Ludlow pulled the data up on his computer, Manning was stunned. He instantly recognised the dates of some of the volcanoes as corresponding with times of upheaval in Ptolemaic Egypt.
“It almost looked too good to be true,” Manning said. “And that’s when we started to work.”
The two researchers teamed up with William Boos, who studies the fluid dynamics of tropical atmosphere with an emphasis on monsoon circulations to try to understand how an explosive volcano in a different part of the world can affect the East African monsoon season.
Scientists find global warming is slowed by eruptions of volcanoes
The authors explain that sulphurous gases released during a powerful volcano can form reflective sulphate aerosols in the stratosphere. Because these aerosols reflect solar radiation, they lead to a cooling effect that can last for one to two years. This, in turn, affects what is known as the hydroclimate, including the amount of surface evaporation and rainfall.
“It’s an indirect response, but because of atmospheric circulation and energy budgets, we find that large volcanic eruptions cause droughts, particularly in monsoon areas,” Manning said.
He added that the effect on the Nile watershed appeared to be greatest for volcanoes in the high northern latitudes of the globe.
To see how this dynamic played out in the real world, the authors compared the dates of ancient volcanic explosions from ice cores in Greenland and Antarctica to the Islamic Nilometre – an ancient record of the heights of the Nile’s annual summer flood.

The Islamic Nilometre, which stretches more than 1,000 years from 622 till 1902, is the longest-known annually recorded observational hydrological record, the authors wrote.
Through this work, they found that the flood height of the Nile during an eruption year was consistently lower than during non-eruption years, in all but one case.
“On average, the impact of an explosive volcano reduces river flooding by 25 per cent below the mean,” Manning said.
Although the Nilometre did not go back to the time of Ptolemaic Egypt, the authors still were able to compare data about the timing of ancient volcanoes with socioeconomic and political activity from that era. They were aided by a trove of well-dated records, particularly papyri, that survived.
The researchers found an increase in revolts against Ptolemaic rule in eruption years, suggesting the events might have been triggered by the stress of the Nile failure and not by overtaxation or resentment of Greek rule, as previously has been thought.
Volcanoes: our unpredictable, often dangerous, reminder of a planet still in formation
And while they discovered no relationship between volcanic explosions and the initiation of wars, the group did find that ongoing wars were more likely to cease after a violent volcano.
This could be because soon after volcanic eruptions altered the Nile flow, warrior kings had to leave the battlefield and return home to mitigate civil unrest.
For example, after major volcanic eruptions in 247 and 244, historical documents suggest that Ptolemy III was called to address food shortages at home just as he and his troops were about to enter Babylon.
“If he had stayed, he might have conquered the entire Near East – possibly changing the course of human history,” Manning said.


Volcanoes in Alaska, Greenland and Russia could have affected lives of ancient Egyptians: study

This image released by the US Geological Survey (USGS) and the Alaska Volcano Observatory (AVO) shows ash deposits from eruptions of Redoubt volcano in 2009 in Alaska. A study showed volcanic eruptions may have affected the lives of ancient Egyptians. Photo: USGS/AVO via AFP

This photo provided by the Alaska Volcano Observatory/ U.S. Geological Survey, steam and ash billows from Augustine Volcano in Alaska on Sunday Jan. 29, 2006. The ash cloud, seen on the right is drifting south southwest sending ash towards the Shelikof Strait and Kodiak Island. The latest in a recent series of eruptions, from the volcano 75 miles southwest of Homer, Alaska at 11:17 a.m., lasted between five and six minutes, according to the Alaska Volcano Observatory with ash being reported from greater than 50,000 feet above sea level on the basis of pilot reports, to 25,000 feet from the National Weather Service radar. (AP Photo/ Alaska Volcano Observatory / U.S. Geological Survey, Kristi Wallace)

In this image provided by NASA a fortuitous orbit of the International Space Station allowed the astronauts this striking view of Sarychev volcano, in Russia's Kuril Islands, northeast of Japan, in an early stage of eruption on June 12, 2009. The main column is one of a series of plumes that rose above Matua Island on June 12. The plume appears to be a combination of brown ash and white steam. The vigorously rising plume gives the steam a bubble-like appearance; the surrounding atmosphere has been shoved up by the shock wave of the eruption. The smooth white cloud on top may be water condensation that resulted from rapid rising and cooling of the air mass above the ash column, and is probably a transient feature. The structure also indicates that little to no shearing winds were present at the time to disrupt the plume. (AP Photo/NASA)

Tech

Science & Research