Preface.  Another repercussion of drought may be the Muslim religion as Fleitmann (2022) proposes below.

This post began with 10 civilizations that collapsed due to drought (below), and I’ve added 5 more. Will the American South West be #16? Lynn Ingram, a professor at U.C. Berkeley discusses this possibility in her  book: The West without Water: What Past Floods, Droughts, and Other Climatic Clues Tell Us about Tomorrow.  Since 2000, California and the South West have had the worst drought in 1,200 years.  Since California’s aquifer and the Ogallala under 10 states produce half of America’s food, the rest of the nation won’t escape…

Alice Friedemann  www.energyskeptic.com  Author of Life After Fossil Fuels: A Reality Check on Alternative Energy; When Trucks Stop Running: Energy and the Future of Transportation”, Barriers to Making Algal Biofuels, & “Crunch! Whole Grain Artisan Chips and Crackers”.  Women in ecology  Podcasts: WGBH, Jore, Planet: Critical, Crazy Town, Collapse Chronicles, Derrick Jensen, Practical Prepping, Kunstler 253 &278, Peak Prosperity,  Index of best energyskeptic posts

***

Fleitmann D et al (2022) Droughts and societal change: The environmental context for the emergence of Islam in late Antique Arabia. Science 376: 1317-1321

In Arabia, the first half of the sixth century CE was marked by the demise of Himyar, the dominant power in Arabia until 525 CE. Important social and political changes followed, which promoted the disintegration of the major Arabian polities. Using hydroclimate and stalagmite records from around Southern Arabia, we clearly see unprecedented droughts during the sixth century CE, with the worst of it from ~500 to 530 CE. We suggest that such droughts undermined the resilience of Himyar and thereby contributed to the societal changes from which Islam emerged.

Scroxton J (2020) Circum-Indian ocean hydroclimate at the mid to late Holocene transition: The Double Drought hypothesis and consequences for the Harappan. Climate Past discussions.

The Harappan arose in the Indus valley near Afghanistan and India about 5200 years ago, peaking around 2600 BC. Their written script remains undeciphered, but archeology has revealed skilled metallurgy, intricate sewer systems, reservoirs, public baths and urban planning long before the Roman Empire. But by 1300 BC it collapsed. Scroxton found a sudden drought starting around 2240 BC affecting winter rain fall, and many fled to present-day Indian Gujarat, while others coped by switching to millet and grains that favored summer rain. Then 300 years later, just as the winter rains began to recover, a tropical drought came, reducing the summer rains for several centuries, greatly reducing the population.

Sinha A et al (2019) Role of climate in the rise and fall of the Neo-Assyrian Empire. Science Advances.

New research suggests it was drought that led to the collapse of the Assyrian Empire (whose heartland was based in today’s northern Iraq)—one of the most powerful civilizations in the ancient world.  Neo-Assyria was the first super power in the history of the world. The Neo-Assyrian empire (912-609 BC) was the third and final phase of Assyrian civilization. It was by far the largest empire in the region up to that time, controlling much of the territory from the Persian Gulf to Cyprus. The Assyrians were basically like the Empire in Star Wars, they are the all-devouring machine.

They also had incredible skill as hydro-engineers. The Assyrians were largely responsible for the way that the Tigris River Basin drainage now works, they completely remade the natural water flows of that landscape using aqueducts and other hydraulic infrastructure. Some of these features are still functioning today.

Today Iraq is water challenged, with a low level per capita of fresh water, and until a deluge in the winter of 2019, very little rain since 1988.

Masters J (2016) Ten Civilizations or Nations That Collapsed From Drought.  wunderground

Drought is the great enemy of human civilization. Drought deprives us of the two things necessary to sustain life–food and water. When the rains stop and the soil dries up, cities die and civilizations collapse, as people abandon lands no longer able to supply them with the food and water they need to live. While the fall of a great empire is usually due to a complex set of causes, drought has often been identified as the primary culprit or a significant contributing factor in a surprising number of such collapses. Drought experts Justin Sheffield and Eric Wood of Princeton, in their 2011 book, Drought, identify more than ten civilizations, cultures and nations that probably collapsed, in part, because of drought. As we mark World Water Day on March 22, we should not grow overconfident that our current global civilization is immune from our old nemesis–particularly in light of the fact that a hotter climate due to global warming will make droughts more intense and impacts more severe. So, presented here is a “top ten” list of drought’s great power over some of the mightiest civilizations in world history–presented chronologically.

Collapse #1. The Akkadian Empire in Syria, 2334 BC – 2193 BC. In Mesopotamia 4200 years ago, the great Akkadian Empire united all the indigenous Akkadian-speaking Semites and the Sumerian speakers, and controlled Mesopotamia, the Levant, and parts of Iran, sending military expeditions as far south as present-day Oman. In a 2000 article published in Geology, “Climate change and the collapse of the Akkadian empire: Evidence from the deep sea”, a team of researchers led by Heidi Cullen studied deposits of continental dust blown into the Gulf of Oman in the late 1990s. They discovered a large increase in dust 4200 years ago that likely coincided with a 100-year drought that brought a 30% decline in precipitation to Syria. The drought, called the 4.2 kiloyear event, is thought to have been caused by cooler sea surface temperatures in the North Atlantic. The 4.2 kiloyear event has also been linked to the collapse of the Old Kingdom in Egypt (see below). The paper concluded, “Geochemical correlation of volcanic ash shards between the archeological site and marine sediment record establishes a direct temporal link between Mesopotamian aridification and social collapse, implicating a sudden shift to more arid conditions as a key factor contributing to the collapse of the Akkadian empire.”

Collapse #2. The Old Kingdom of ancient Egypt, 4200 years ago. The same drought that brought down the Akkadian empire in Syria severely shrank the normal floods on the Nile River in ancient Egypt. Without regular floods to fertilize the fields, poor harvests led to reduced tax income and insufficient funds to finance the pharaoh’s government, hastening the collapse of Egypt’s pyramid-building Old Kingdom. An inscription on the tomb of Ankhtifi during the collapse describes the pitiful state of the country when famine stalked the land: “the whole country has become like locusts going in search of food…”

Collapse #3. The Late Bronze Age (LBA) civilization in the Eastern Mediterranean. About 3200 years ago, the Eastern Mediterranean hosted some of the world’s most advanced civilizations. The Mycenaean culture was flourishing in Greece and Crete. The chariot-riding Hittites had carved out a vast empire encompassing a large part of Asa Minor and the Middle East. In Egypt, the New Kingdom was at its height. However, around 1200 BC, these Eastern Mediterranean civilizations declined or collapsed. According to a 2013 study in PLOS, studying grains of fossilized pollen shows that this collapse coincided with the onset of a 300-year drought event. This climate shift caused crop failures and famine, which “precipitated or hastened socio-economic crises and forced regional human migrations at the end of the LBA in the Eastern Mediterranean and southwest Asia.”

Collapse #4. The Maya civilization of 250-900 AD in Mexico. Severe drought killed millions of Maya people due to famine and lack of water, and initiated a cascade of internal collapses that destroyed their civilization at the peak of their cultural development, between 750 – 900 AD. Haug, G.H. et al., in their 2003 paper in Science, “Climate and the collapse of Maya civilization,” documented substantial multi-year droughts coinciding with the collapse of the Maya civilization.

Collapse #5. Another Mayan collapse occurred a few centuries later. Mayapan served as the capital to some 20,000 Maya people in the 13th through mid-15th centuries but collapsed and was abandoned after a rival political faction, the Xiu, massacred the powerful Cocom family. Extensive historical records date this collapse to sometime between 1441 and 1461. Plenty of ethnohistorical records exist to support the city’s violent downfall and abandonment around 1458, she said. But the new evidence of massacre up to 100 years earlier, together with climate data that found prolonged drought around that time, led the team to suspect environmental factors may have played a role.  In particular, researchers found a significant relationship between a period of drought and substantial population decline from 1350 to 1430.

The Maya depended heavily on rain-fed maize but lacked any centralized long-term grain storage. The impacts of rainfall levels on food production, then, are believed to be linked to human migration, population decline, warfare and shifts in political power, the study states. “It’s not that droughts cause social conflict, but they create the conditions whereby violence can occur, that hardship can become politicized in the worst kind of way,” Masson said. “It creates opportunities for ruthlessness and can cause people to turn on one another violently.” (Kennett 2022)

Collapse #6. The Tang Dynasty in China, 700-907 AD. At the same time as the Mayan collapse, China was also experiencing the collapse of its ruling empire, the Tang Dynasty. Dynastic changes in China often occurred because of popular uprisings during crop failure and famine associated with drought. The Tang dynasty–a golden age of literature and art in Chinese civilization–began to weaken in the eighth century, and it fully collapsed in 907 AD. Sediments from Lake Huguang Maar in China dated to the time of the collapse of the Tang Dynasty indicate a sudden and sustained decline in summertime monsoon rainfall. Agriculture in China depends upon the summer monsoon, which supplies about 70% of the year’s rain in just a few months. A 2007 article in Nature by Yancheva et al. speculated that “migrations in the tropical rain belt could have contributed to the simultaneous declines of both the Tang dynasty in China and the Classic Maya in Central America.”

Collapse 7. The Tiwanaku Empire of Bolivia’s Lake Titicaca region, 300 – 1000 AD. The Tiwanaku Empire was one of the most important South American civilizations prior to the Inca Empire. After dominating the region for 500 years, the Tiwanaku Empire ended abruptly between 1000 – 1100 AD, following a drying of the region, as measured by ice accumulation in the Quelccaya Ice Cap, Peru. Sediment cores from nearby Lake Titicaca document a 10-meter drop in lake level at this time.

Collapse 8. The Ancestral Puebloan Anasazi culture in the Southwest U.S. in the 11th-12th centuries AD. Beginning in 1150 AD, North America experienced a 300-year drought called the Great Drought. This drought has often been cited as a primary cause of the collapse of the ancestral Puebloan (formally called Anasazi) civilization in the Southwest U.S., and abandonment of places like the Cliff Palace at Mesa Verde National Park in Colorado. The Mississippian culture, a mound-building Native American civilization that flourished in what is now the Midwestern, Eastern, and Southeastern United States, also collapsed at this time.

Collapse #9. The Khmer Empire based in Angkor, Cambodia, 802-1431 AD. The Khmer Empire ruled Southeast Asia for over 600 years, but was done in by a series of intense decades-long droughts interspersed with intense monsoons in the fourteenth and fifteenth centuries that, in combination with other factors, contributed to the empire’s demise. The climatic evidence comes from a seven-and-a-half century reconstruction from tropical southern Vietnamese tree rings presented in a 2010 study by Buckley et al., “Climate as a contributing factor in the demise of Angkor, Cambodia”. They wrote: “The Angkor droughts were of a duration and severity that would have impacted the sprawling city’s water supply and agricultural productivity, while high-magnitude monsoon years damaged its water control infrastructure.”

Collapse #10. The Ming Dynasty in China, 1368-1644 AD. China’s Ming Dynasty–one of the greatest eras of orderly government and social stability in human history–collapsed at a time when the most severe drought in the region in over 4000 years was occurring, according to sediments from Lake Huguang Maar analyzed in a 2007 article in Nature by Yancheva et al. Drought experts Justin Sheffield and Eric Wood of Princeton, in their 2011 book, Drought, speculated that a weakened summer monsoon driven by warm El Niño conditions in the Eastern Pacific was responsible for the intense drought, which led to widespread famine. An inscription found carved on a wall of Dayu Cave in the Qinling Mountains of Central China dated July 10, 1596, during the 24th year of the MIng Dynasty’s Emperor Wanli, said: Mountains are crying due to drought.”

Collapse #11. Modern Syria. Syria’s devastating civil war that began in March 2011 has killed over 300,000 people, displaced at least 7.6 million, and created an additional 4.2 million refugees. While the causes of the war are complex, a key contributing factor was the nation’s devastating drought that began in 1998. The drought brought Syria’s most severe set of crop failures in recorded history, which forced millions of people to migrate from rural areas into cities, where conflict erupted. This drought was almost certainly Syria’s worst in the past 500 years (98% chance), and likely the worst for at least the past 900 years (89% chance), according to a 2016 tree ring study by Cook et al., “Spatiotemporal drought variability in the Mediterranean over the last 900 years.” Human-caused emissions greenhouse gases were “a key attributable factor” in the drying up of wintertime precipitation in the Mediterranean region, including Syria, in recent decades, as discussed in a NOAA press release that accompanied a 2011 paper by Hoerling et al., On the Increased Frequency of Mediterranean Drought. A 2016 paper by drought expert Colin Kelley showed that the influence of human greenhouse gas emissions had made recent drought in the region 2 – 3 times more likely. Wunderground’s climate change blogger, Dr. Ricky Rood, has his take on the current drought in Syria in his March 21 post, Ineffective Resolution: Middle East and Climate Change.

Collapse #12 Mycenaean Greece   Marshall (2012) Climate change: The great civilisation destroyer?  War and unrest, and the collapse of many mighty empires, often followed changes in local climes. Is this more than a coincidence?  NewScientist.  Also see: “Five civilisations that climate change may have doomed“

What caused the collapse of Mycenaean Greece, and thus had a huge impact on the course of world history? A change in the climate, according to the latest evidence. What’s more, Mycenaean Greece is just one of a growing list of civilizations whose fate is being linked to the vagaries of climate. It seems big swings in the climate, handled badly, brought down whole societies, while smaller changes led to unrest and wars.

Excavating in what is now Syria, Weiss found dust deposits suggesting that the region’s climate suddenly became drier around 2200 BC. The drought would have led to famine, he argued, explaining why major cities were abandoned at this time (Science, vol 261, p 995). A piece of contemporary writing, called The Curse of Akkad, does describe a great famine:

For the first time since cities were built and founded,
The great agricultural tracts produced no grain,
The inundated tracts produced no fish,
The irrigated orchards produced neither syrup nor wine,
The gathered clouds did not rain, the masgurum did not grow.
At that time, one shekel’s worth of oil was only one-half quart,
One shekel’s worth of grain was only one-half quart. …
These sold at such prices in the markets of all the cities!
He who slept on the roof, died on the roof,
He who slept in the house, had no burial,
People were flailing at themselves from hunger.

In 2000, climatologist Peter deMenocal of Columbia University in New York found more. His team showed, based on modern records going back to 1700, that the flow of the region’s two great rivers, the Tigris and the Euphrates, is linked to conditions in the north Atlantic: cooler waters reduce rainfall by altering the paths of weather systems. Next, they discovered that the north Atlantic cooled just before the Akkadian empire fell apart (Science, vol 288, p 2198). “To our surprise we got this big whopping signal at the time of the Akkadian collapse.”

It soon became clear that major changes in the climate coincided with the untimely ends of several other civilizations (see map). Of these, the Maya became the poster child for climate-induced decline. Mayan society arose in Mexico and Central America around 2000 BC.

Then the Mayan civilization collapsed.  Numerous studies have shown that there were several prolonged droughts around the time of the civilisation’s decline. In 2003, Gerald Haug of the Swiss Federal Institute of Technology in Zurich found it was worse than that. His year-by-year reconstruction based on lake sediments shows that rainfall was abundant from 550 to 750, perhaps leading to a rise in population and thus to the peak of monument-building around 721. But over the next century there were not only periods of particularly severe drought, each lasting years, but also less rain than normal in the intervening years (Science, vol 299, p 1731). Monument construction ended during this prolonged dry period, around 830, although a few cities continued on for many centuries.

When the climate becomes less favorable, less food can be grown. Such changes can also cause plagues of locusts or other pests, and epidemics among people weakened by starvation. When it is no longer feasible to maintain a certain population level and way of life, the result can be collapse.

In 2010, though, a study of river deposits in Syria suggested there was a prolonged dry period between 1200 and 850 BC – right at the time of the so-called Greek Dark Ages. Earlier this year, Drake analyzed several climate records and concluded that there was a cooling of the Mediterranean at this time, reducing evaporation and rainfall over a huge area.

What’s more, several other cultures around the Mediterranean, including the Hittite Empire and the “New Kingdom” of Egypt, collapsed around the same time as the Mycenaeans – a phenomenon known as the late Bronze Age collapse. Were all these civilizations unable to cope with the changing climate? Or were the invading Sea Peoples the real problem? The story could be complex: civilizations weakened by hunger may have become much more vulnerable to invaders, who may themselves have been driven to migrate by the changing climate. Or the collapse of one civilization could have had knock-on effects on its trading partners.

Around 900, the Tang dynasty began losing its grip on China. At its height, the Tang ruled over 50 million subjects. Woodblock printing meant that written words, particularly poetry, were widely accessible. But the dynasty fell after local governors usurped its authority. A study of lake sediments in China by Haug suggests that this region experienced a prolonged dry period at the same time as that in Central America. He thinks a shift in the tropical rain belt was to blame, causing civilisations to fall apart on either side of the Pacific (Nature, vol 445, p 74).

From 2500 BC until the 20th century, a series of powerful empires like the Tang controlled China. All were eventually toppled by civil unrest or invasions.  When Zhang compared climate records for the last 1200 years to the timeline of China’s dynastic wars, the match was striking. Most of the dynastic transitions and periods of social unrest took place when temperatures were a few tenths of a degree colder. Warmer periods were more stable and peaceful (Chinese Science Bulletin, vol 50, p 137).

Zhang gradually built up a more detailed picture showing that harvests fell when the climate was cold, as did population levels, while wars were more common. Of 15 bouts of warfare he studied, 12 took place in cooler times. He then looked at records of war across Europe, Asia and north Africa between 1400 and 1900. Once again, there were more wars when the temperatures were lower. Cooler periods also saw more deaths and declines in the population.

These studies suggest that the effects of climate on societies can be profound.

Trying to move beyond mere correlations, Zhang began studying the history of Europe from 1500 to 1800 AD. In the mid-1600s, Europe was plunged into the General Crisis, which coincided with a cooler period called the Little Ice Age. The Thirty Years war was fought then, and many other wars. Zhang analyzed detailed records covering everything from population and migration to agricultural yields, wars, famines and epidemics in a bid to identify causal relationships. So, for instance, did climate change affect agricultural production and thus food prices? That in turn might lead to famine – revealed by a reduction in the average height of people – epidemics and a decline in population. High food prices might also lead to migration and social unrest, and even wars.

References

Buckley, B.M. et al., 2010, “Climate as a contributing factor in the demise of Angkor, Cambodia,” Proc. Natl. Acad. Sci. U.S.A. 107, 6748–6752 (2010).

Cook, B.I. et al., 2016, “Spatiotemporal drought variability in the Mediterranean over the last 900 years,” JGR Atmospheres, DOI: 10.1002/2015JD023929

Cullen, H.M., and P.B. deMenocal, 2000, North Atlantic Influence on TIgris-Euphrates Streamflow, International Journal of Climatology, 20: 853-863.

Cullen et al., 2000, “Climate change and the collapse of the Akkadian empire: Evidence from the deep sea,” Geology 28, 379 (2000).

deMenocal, P.B., 2001, “Cultural responses to climate change during the late Holocene,” Science 292, 667–673 (2001).

Gleick, P., 2014, Water, Drought, Climate Change, and Conflict in Syria, Weather, Climate, and Society

Haug, G.H. et al., 2003, “Climate and the collapse of Maya civilization,” Science 299, 1731–1735 (2003).

Hoerling, Martin, Jon Eischeid, Judith Perlwitz, Xiaowei Quan, Tao Zhang, Philip Pegion, 2012, On the Increased Frequency of Mediterranean Drought, J. Climate, 25, 2146–2161, doi: http://dx.doi.org/10.1175/JCLI-D-11-00296.1

Kaniewski, D. et al., 2012, Drought is a recurring challenge in the Middle East, PNAS 109:10, 3862–3867, doi: 10.1073/pnas.1116304109

Kaniewski, D. et al., 2013, “Environmental Roots of the Late Bronze Age Crisis,” PLOS one, DOI: 10.1371/journal.pone.0071004

Kelley, C.P. et al., 2016, “Climate change in the Fertile Crescent and implications of the recent Syrian drought,” PNAS vol. 112 no. 11, 3241–3246, doi: 10.1073/pnas.1421533112

Kennett DJ et al (2022) Drought-Induced Civil Conflict Among the Ancient Maya, Nature Communications. DOI: 10.1038/s41467-022-31522-x

Ortloff, C.R. and A.L. Kolata, 1992, “Climate and Collapse: Agro-Ecological Perspectives on the Decline of the Tiwanaku State,” J. of Achaelogical Science 1993, <b<20< b=””> 195-221.

Wendel, JoAnna, 2015, Chinese Cave Inscriptions Tell Woeful Tale of Drought,” EOS, 1 October 2015.

Yancheva, G. et al., 2007, “Influence of the intertropical convergence zone on the East Asian monsoon,” Nature 445, 74–77 (2007).