Nav: Home

Study reshapes understanding of climate change's impact on early societies

October 17, 2017

A new study linking paleoclimatology -- the reconstruction of past global climates -- with historical analysis by researchers at Yale and other institutions shows a link between environmental stress and its impact on the economy, political stability, and war-fighting capacity of ancient Egypt.

The team of researchers examined the hydroclimatic and societal impacts in Egypt of a sequence of tropical and high-latitude volcanic eruptions spanning the past 2,500 years, as known from modern ice-core records. The team focused on the Ptolemaic dynasty of ancient Egypt (305-30 B.C.E.) -- a state formed in the aftermath of the campaigns of Alexander the Great, and famed for rulers such as Cleopatra -- as well as material and cultural achievements including the great Library and Lighthouse of Alexandria.

Using an interdisciplinary approach that combined evidence from climate modelling of large 20th-century eruptions, annual measurements of Nile summer flood heights from the Islamic Nilometer -- the longest-known human record of environmental variability -- between 622 and 1902, as well as descriptions of Nile flood quality in ancient papyri and inscriptions from the Ptolemaic era, the authors show how large volcanic eruptions impacted on Nile river flow, reducing the height of the agriculturally-critical summer flood.

The findings, published in the journal Nature Communications, show that integrating evidence from historical writings with paleoclimate data can advance both our understanding of how the climate system functions, and how climatic changes impacted past human societies.

"Ancient Egyptians depended almost exclusively on Nile summer flooding brought by the summer monsoon in east Africa to grow their crops. In years influenced by volcanic eruptions, Nile flooding was generally diminished, leading to social stress that could trigger unrest and have other political and economic consequences," says Joseph Manning, lead author on the paper and the William K. & Marilyn Milton Simpson Professor of History and Classics at Yale.

The reason for reduced flooding of the Nile is because volcanic eruptions can disrupt the climate by injecting sulfurous gases into the stratosphere, says Francis Ludlow, the study's corresponding author. Ludlow is a climate historian who began collaborating with Manning as a postdoctoral fellow at Yale, and is now based in history in Trinity College, Dublin. These gases react to form aerosols that remain in the atmosphere in decreasing concentrations for one or two years, reflecting incoming solar radiation back to space. These volcanic aerosols can influence global hydroclimate. The reduction in surface temperatures can lead to reduced evaporation over waterbodies, and hence lessen rainfall. If the aerosols are dispersed primarily in the Northern Hemisphere, the greater cooling in this hemisphere can also diminish the summertime heating that drives the northward migration of monsoon winds over Africa up to the Ethiopian highlands where the Blue Nile is supplied with its summer floodwaters.

Because the Ptolemaic era is one of ancient Egypt's most well-documented periods, the dates of major political events are known with some confidence, note the researchers, adding that what is often less clear from the ancient writings is what specific factors triggered events like revolts. The researchers were able to show a recurring close timing between such events and the dates of major volcanic eruptions. Knowledge of the historical context is essential to fully understanding how shocks from diminished Nile flooding acted to trigger revolts and constrain Ptolemaic war making, say the researchers, explaining that the shocks from poor Nile flooding would have occurred against a background of multiple socioeconomic and political difficulties that would have compounded the impacts of Nile variability.

"Egypt and the Nile are very sensitive instruments for climate change, and Egypt provides a unique historical laboratory in which to study social vulnerability and response to abrupt volcanic shocks," says Manning. "Nile flood suppression from historical eruptions has been little studied, despite well documented Nile failures with severe social impacts coinciding with eruptions in 939, in 1783-1784 in Iceland, and 1912 in Alaska," he adds.

"With volcanic eruption dates fixed precisely in time, we can see society in motion around them. This is the first time for ancient history that we can begin to talk about a dynamic understanding of society," says Manning.

According to Manning, this research not only alters the perception of climatic changes on various scales, from short-term shocks to slower-moving, long-term changes, but it is also revolutionizing the understanding of human societies and how the forces of nature shaped them in the past. "The study is of particular importance for the current debate about climate change," says Manning.

"It is very rare in science and history to have such strong and detailed evidence documenting how societies responded to climatic shocks in the past," says Jennifer Marlon, research scientist in the Yale School of Forestry & Environmental Studies, and a co-author on the study.

The study reflects a significant advance in the integration of research among scientists and historians, and points to the need for more interdisciplinary scholarship to better document and analyze how humans have related and responded to past environmental changes, says Marlon.

The researchers note that the study provides historical context for what is happening today and what may happen in the future and demonstrates that there is need for further investigation into the effects of climate change on modern societies worldwide.

"There hasn't been a large eruption affecting the global climate system since Mount Pinatubo in the Philippines in 1991," says Manning. "We are living in a period where we are fairly quiescent in terms of large volcanic eruptions that are affecting climate. A lot of volcanoes erupt each year but they are not affecting the climate system on the scale of some past eruptions. Sooner or later we will experience a large volcanic eruption, and perhaps a cluster of them, that will act to exacerbate drought in sensitive parts of the world."
-end-
Other authors on the study are Alexander R. Stine, San Francisco State University; William R. Boos, University of California-Berkeley; and Michael Sigl, Paul Scherrer Institute.

Yale University

Related Climate Change Articles:

The black forest and climate change
Silver and Douglas firs could replace Norway spruce in the long run due to their greater resistance to droughts.
For some US counties, climate change will be particularly costly
A highly granular assessment of the impacts of climate change on the US economy suggests that each 1°Celsius increase in temperature will cost 1.2 percent of the country's gross domestic product, on average.
Climate change label leads to climate science acceptance
A new Cornell University study finds that labels matter when it comes to acceptance of climate science.
Was that climate change?
A new four-step 'framework' aims to test the contribution of climate change to record-setting extreme weather events.
It's more than just climate change
Accurately modeling climate change and interactive human factors -- including inequality, consumption, and population -- is essential for the effective science-based policies and measures needed to benefit and sustain current and future generations.
Climate change scientists should think more about sex
Climate change can have a different impact on male and female fish, shellfish and other marine animals, with widespread implications for the future of marine life and the production of seafood.
Climate change prompts Alaska fish to change breeding behavior
A new University of Washington study finds that one of Alaska's most abundant freshwater fish species is altering its breeding patterns in response to climate change, which could impact the ecology of northern lakes that already acutely feel the effects of a changing climate.
Uncertainties related to climate engineering limit its use in curbing climate change
Climate engineering refers to the systematic, large-scale modification of the environment using various climate intervention techniques.
Public holds polarized views about climate change and trust in climate scientists
There are gaping divisions in Americans' views across every dimension of the climate debate, including causes and cures for climate change and trust in climate scientists and their research, according to a new Pew Research Center survey.
The psychology behind climate change denial
In a new thesis in psychology, Kirsti Jylhä at Uppsala University has studied the psychology behind climate change denial.

Related Climate Change Reading:

The Politically Incorrect Guide to Climate Change (The Politically Incorrect Guides)
by Marc Morano (Author)

Less freedom. More regulation. Higher costs. Make no mistake: those are the surefire consequences of the modern global warming campaign waged by political and cultural elites, who have long ago abandoned fact-based science for dramatic fearmongering in order to push increased central planning. The Politically Incorrect Guide to Climate Change gives a voice -- backed by statistics, real-life stories, and incontrovertible evidence -- to the millions of "deplorable" Americans skeptical about the multibillion dollar "climate change" complex, whose claims have time and time again been... View Details


Climate Change: What Everyone Needs to Know®
by Joseph Romm (Author)

Climate change will have a bigger impact on humanity than the Internet has had. The last decade's spate of superstorms, wildfires, heat waves, and droughts has accelerated the public discourse on this topic and lent credence to climatologist Lonnie Thomson's 2010 statement that climate change "represents a clear and present danger to civilization." In June 2015, the Pope declared that action on climate change is a moral issue.

This book offers the most up-to-date examination of climate change's foundational science, its implications for our future, and the core clean energy solutions.... View Details


This Changes Everything: Capitalism vs. The Climate
by Naomi Klein (Author)

The most important book yet from the author of the international bestseller The Shock Doctrine, a brilliant explanation of why the climate crisis challenges us to abandon the core “free market” ideology of our time, restructure the global economy, and remake our political systems.

In short, either we embrace radical change ourselves or radical changes will be visited upon our physical world. The status quo is no longer an option.

In This Changes Everything Naomi Klein argues that climate change isn’t just another issue to be neatly filed between taxes and... View Details


Climate Change: What Everyone Needs to Know®
by Joseph Romm (Author)

"This is, for my money, the best single-source primer on the state of climate change." - New York Magazine

"The right book at the right time: accessible, comprehensive, unflinching, humane." - The Daily Beast

"A must-read." - The Guardian

The essential primer on what will be the defining issue of our time, Climate Change: What Everyone Needs to Know® is a clear-eyed overview of the science, conflicts, and implications of our warming planet.

From Joseph Romm, Chief Science... View Details


Lyme: The First Epidemic of Climate Change
by Mary Beth Pfeiffer (Author)

"Superbly written and researched." Booklist

"Builds a strong case." Kirkus

Lyme disease is spreading rapidly around the globe as ticks move into places they could not survive before. The first epidemic to emerge in the era of climate change, the disease infects half a million people in the US and Europe each year, and untold multitudes in Canada, China, Russia, and Australia.

Mary Beth Pfeiffer shows how we have contributed to this growing menace, and how modern medicine has underestimated its danger. She... View Details


Climate Change: The Facts
by J.Abbot (Author), J.S. Armstrong (Author), A.Bolt (Author), R.Carter (Author), R.Darwall (Author), J.Delingpole (Author), C.Essex (Author), S.Franks (Author), K.Green (Author), D.Laframboise (Author), N.Lawson (Author), B.Lewin (Author), R.Lindzen (Author), J.Marohasy (Author), R.McKitrick (Author), P.Michaels (Author), A.Moran (Author), J.Nova (Author), G.Paltridge (Author), I.Plimer (Author), W.Soon (Author), M.Steyn (Author), A.Watts (Author), Alan Moran (Editor)

Tirelessly promoted by princes, presidents, actors and activists, "climate change" has become a dominant theme of global politics. But what's really going on as the "pause" in global warming prepares to enter its third decade? In this new anthology, leading scientists and commentators from the United States, the United Kingdom, Canada and Australia consider the climate from every angle - the science, the policy and the politics. View Details


A Global Warming Primer: Answering Your Questions About The Science, The Consequences, and The Solutions
by Jeffrey Bennett (Author)

Winner:
2017 NSTA, Outstanding Science Trade Books
2017 Children's Book Council, Best STEM Books
Nautilus Book Award, Silver, Ecology and Environment

Is human-induced global warming a real threat to our future? Most people will express an opinion on this question, but relatively few can back their opinions with solid evidence. Many times we’ve even heard pundits say “I am not a scientist” to avoid the issue altogether. But the truth is, the basic science is not that difficult. Using a question and answer format, this book will help readers achieve three major... View Details


Climate Change: The Facts 2017
by Jennifer Marohasy (Editor)

Climate Change: The Facts 2017 contains 22 essays by internationally-renowned experts and commentators, including Dr Bjorn Lomborg, Dr Matt Ridley, Professor Peter Ridd, Dr Willie Soon, Dr Ian Plimer, Dr Roy Spencer, and literary giant Clive James. The volume is edited by Dr Jennifer Marohasy, Senior Fellow at the Institute of Public Affairs. Fourteen of the contributors currently hold or have held positions at a university or a scientific research organisation.

Dr Jennifer Marohasy said, "Climate Change: The Facts 2017 presents the case for climate change policies... View Details


Dire Predictions, 2nd Edition: Understanding Climate Change
by Michael E. Mann (Author), Lee R. Kump (Author)

Explore global warming with graphics, illustrations, and charts that separate climate change fact from fiction, presenting the truth about global warming in a way that's both accurate and easy to understand. Respected climate scientists Michael E. Mann and Lee R. Kump address important questions about global warming and climate change, diving into the information documented by the IPCC (Intergovernmental Panel on Climate Change) and breaking it down into clear graphics that explain complex climate questions in simple illustrations that present the truth of the global warming problem clearly.... View Details


Climate Change (True Books: Ecosystems (Paperback))
by Peter Benoit (Author)

Describes the impact of climate change on animals, plants, and humans. View Details

Best Science Podcasts 2018

We have hand picked the best science podcasts for 2018. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Turning Kids Into Grown-Ups
Parenting is fraught with uncertainty, changing with each generation. This hour, TED speakers share ideas about raising kids and how — despite our best efforts — we're probably still doing it wrong. Guests include former Stanford dean Julie Lythcott-Haims, former firefighter Caroline Paul, author Peggy Orenstein, psychologist Dr. Aala El-Khani, and poet Sarah Kay.
Now Playing: Science for the People

#470 Information Spookyhighway
This week we take a closer look at a few of the downsides of the modern internet, and some of the security and privacy challenges that are becoming increasingly troublesome. Rachelle Saunders speaks with cyber security expert James Lyne about how modern hacking differs from the hacks of old, and how an internet without national boards makes it tricky to police online crime across jurisdictions. And Bethany Brookshire speaks with David Garcia, a computer scientist at the Complexity Science Hub and the Medical University of Vienna, about the recent Cambridge Analytica scandal, and how social media platforms put a wrench...