Societal collapse (also known as civilizational collapse or systems collapse) is the fall of a complex human
society
A society () is a group of individuals involved in persistent social interaction or a large social group sharing the same spatial or social territory, typically subject to the same political authority and dominant cultural expectations. ...
characterized by the loss of
cultural identity
Cultural identity is a part of a person's identity (social science), identity, or their self-conception and self-perception, and is related to nationality, ethnicity, religion, social class, generation, Locality (settlement), locality, gender, o ...
and of
social complexity
In sociology, social complexity is a conceptual framework used in the analysis of society. In the sciences, contemporary definitions of complexity are found in systems theory, wherein the phenomenon being studied has many parts and many possible ...
as an
adaptive system
An adaptive system is a set of interacting or interdependent entities, real or abstract, forming an integrated whole that together are able to respond to environmental changes or changes in the interacting parts, in a way analogous to either cont ...
, the downfall of
government
A government is the system or group of people governing an organized community, generally a State (polity), state.
In the case of its broad associative definition, government normally consists of legislature, executive (government), execu ...
, and the rise of
violence
Violence is characterized as the use of physical force by humans to cause harm to other living beings, or property, such as pain, injury, disablement, death, damage and destruction. The World Health Organization (WHO) defines violence a ...
.
Possible causes of a societal collapse include natural catastrophe,
war
War is an armed conflict between the armed forces of states, or between governmental forces and armed groups that are organized under a certain command structure and have the capacity to sustain military operations, or between such organi ...
,
pestilence,
famine
A famine is a widespread scarcity of food caused by several possible factors, including, but not limited to war, natural disasters, crop failure, widespread poverty, an Financial crisis, economic catastrophe or government policies. This phenom ...
,
economic collapse
Economic collapse, also called economic meltdown, is any of a broad range of poor economic conditions, ranging from a severe, prolonged depression with high bankruptcy rates and high unemployment (such as the Great Depression of the 1930s), t ...
,
population decline
Population decline, also known as depopulation, is a reduction in a human population size. Throughout history, Earth's total world population, human population has estimates of historical world population, continued to grow but projections sugg ...
or
overshoot,
mass migration
Mass migration refers to the migration of large groups of people from one geographical area to another. Mass migration is distinguished from individual or small-scale migration; and also from seasonal migration, which may occur on a regular basi ...
,
incompetent leaders, and
sabotage
Sabotage is a deliberate action aimed at weakening a polity, government, effort, or organization through subversion, obstruction, demoralization (warfare), demoralization, destabilization, divide and rule, division, social disruption, disrupti ...
by rival civilizations. A collapsed society may revert to a more primitive state, be absorbed into a stronger society, or completely disappear.
Virtually all civilizations have suffered such a fate, regardless of their size or complexity. Most never recovered, such as the Western and Eastern Roman Empires, the
Maya civilization
The Maya civilization () was a Mesoamerican civilization that existed from antiquity to the early modern period. It is known by its ancient temples and glyphs (script). The Maya script is the most sophisticated and highly developed writin ...
, and the
Easter Island civilization.
However, some of them later revived and transformed, such as China, Greece, and Egypt.
Anthropologists, historians, and sociologists have proposed a variety of explanations for the collapse of civilizations involving causative factors such as environmental degradation, depletion of resources, costs of rising complexity, invasion, disease, decay of social cohesion, growing
inequality,
extractive institutions, long-term decline of
cognitive abilities, loss of
creativity
Creativity is the ability to form novel and valuable Idea, ideas or works using one's imagination. Products of creativity may be intangible (e.g. an idea, scientific theory, Literature, literary work, musical composition, or joke), or a physica ...
, and misfortune.
However, complete extinction of a culture is not inevitable, and in some cases, the new societies that arise from the ashes of the old one are evidently its offspring, despite a dramatic reduction in sophistication.
Moreover, the influence of a collapsed society, such as the Western Roman Empire, may linger on long after its death.
The study of societal collapse,
collapsology, is a topic for specialists of
history
History is the systematic study of the past, focusing primarily on the Human history, human past. As an academic discipline, it analyses and interprets evidence to construct narratives about what happened and explain why it happened. Some t ...
,
anthropology
Anthropology is the scientific study of humanity, concerned with human behavior, human biology, cultures, society, societies, and linguistics, in both the present and past, including archaic humans. Social anthropology studies patterns of behav ...
,
sociology
Sociology is the scientific study of human society that focuses on society, human social behavior, patterns of Interpersonal ties, social relationships, social interaction, and aspects of culture associated with everyday life. The term sociol ...
, and
political science
Political science is the scientific study of politics. It is a social science dealing with systems of governance and Power (social and political), power, and the analysis of political activities, political philosophy, political thought, polit ...
. More recently, they are joined by experts in
cliodynamics
Cliodynamics () is a transdisciplinary area of research that integrates cultural evolution, economic history/ cliometrics, macrosociology, the mathematical modeling of historical processes during the '' longue durée'', and the construction and ...
and study of
complex system
A complex system is a system composed of many components that may interact with one another. Examples of complex systems are Earth's global climate, organisms, the human brain, infrastructure such as power grid, transportation or communication sy ...
s.
Concept
Joseph Tainter frames societal collapse in ''
The Collapse of Complex Societies'' (1988), a seminal and founding work of the academic discipline on societal collapse.
He elaborates that 'collapse' is a "broad term", but in the sense of societal collapse, he views it as "a ''political'' process".
[ "What is collapse?
'Collapse' is a broad term that can cover many kinds of processes. It means different
things to different people. Some see collapse as a thing that could happen only to societies organized at the most complex level. To them, the notion of tribal societies or village horticulturalists collapsing will seem odd. Others view collapse in terms of
economic disintegration, of which the predicted end of industrial society is the
ultimate expression. Still others question the very utility of the concept, pointing out that art styles and literary traditions often survive political decentralization.
Collapse, as viewed in the present work, is a political process. It may, and often
does, have consequences in such areas as economics, art, and literature, but it is
fundamentally a matter of the sociopolitical sphere. A society has collapsed when it
displays a rapid, significant loss of an established level of sociopolitical complexity. The
term 'established level' is important. To qualify as an instance of collapse a society
must have been at, or developing toward, a level of complexity for more than one or
two generations. The demise of the Carolingian Empire, thus, is not a case of collapse
- merely an unsuccessful attempt at empire building. The collapse, in turn, must be
rapid - taking no more than a few decades - and must entail a substantial loss of
sociopolitical structure. Losses that are less severe, or take longer to occur, are to be
considered cases of weakness and decline. ..The fall of the Roman Empire is, in the West, the most widely known instance of
collapse, the one which comes most readily to popular thought." (Pages 4-5)] He further narrows societal collapse as a rapid process (within "few decades") of "substantial loss of sociopolitical structure", giving the
fall of the Western Roman Empire
The fall of the Western Roman Empire, also called the fall of the Roman Empire or the fall of Rome, was the loss of central political control in the Western Roman Empire, a process in which the Empire failed to enforce its rule, and its vast ...
as "the most widely known instance of collapse" in the Western world.
Others, particularly in response to the popular ''
Collapse'' (2005) by
Jared Diamond
Jared Mason Diamond (born September 10, 1937) is an American scientist, historian, and author. In 1985 he received a MacArthur Genius Grant, and he has written hundreds of scientific and popular articles and books. His best known is '' Guns, G ...
and more recently, have argued that societies discussed as cases of collapse are better understood through
resilience and
societal transformation, or "reorganization", especially if collapse is understood as a "complete end" of political systems, which according to
Shmuel Eisenstadt has not taken place at any point.
Eisenstadt also points out that a clear differentiation between total or partial decline and "possibilities of regeneration" is crucial for the preventive purpose of the study of societal collapse.
This frame of reference often rejects the term collapse and critiques the notion that cultures simply vanish when the political structures that organize labor for large archaeologically prominent projects do. For example, while the
Ancient Maya
The Maya civilization () was a Mesoamerican civilization that existed from antiquity to the early modern period. It is known by its ancient temples and glyphs (script). The Maya script is the most sophisticated and highly developed writing ...
are often touted as a prime example of collapse, in reality this reorganization was simply the result of the removal of the political system of Divine Kingship largely in the eastern lowlands as many cities in the western highlands of
Mesoamerica
Mesoamerica is a historical region and cultural area that begins in the southern part of North America and extends to the Pacific coast of Central America, thus comprising the lands of central and southern Mexico, all of Belize, Guatemala, El S ...
maintained this system of divine kingship into the 16th century. The Maya continue to maintain cultural and linguistic continuity into the present day.
Societal longevity
The social scientist Luke Kemp analyzed dozens of civilizations, which he defined as "a society with agriculture, multiple cities, military dominance in its geographical region and a continuous political structure", from 3000 BC to 600 AD and calculated that the average life span of a civilization is close to 340 years.
Of them, the most durable were the
Kushite Kingdom in Northeast Africa (1,150 years), the
Aksumite Empire
The Kingdom of Aksum, or the Aksumite Empire, was a kingdom in East Africa and South Arabia from classical antiquity to the Middle Ages, based in what is now northern Ethiopia and Eritrea, and spanning present-day Djibouti and Sudan. Emerging ...
in East Africa (1,100 years), and the
Vedic civilization in South Asia and the
Olmecs
The Olmecs () or Olmec were an early known major Mesoamerican civilization, flourishing in the modern-day Mexican states of Veracruz and Tabasco from roughly 1200 to 400 Before the Common Era, BCE during Mesoamerica's Mesoamerican chronolog ...
in Mesoamerica (both 1,000 years), and the shortest-lived were the
Nanda Empire in India (24) and the
Qin dynasty
The Qin dynasty ( ) was the first Dynasties of China, imperial dynasty of China. It is named for its progenitor state of Qin, a fief of the confederal Zhou dynasty (256 BC). Beginning in 230 BC, the Qin under King Ying Zheng enga ...
in China (14).
A statistical analysis of empires by complex systems specialist Samuel Arbesman suggests that collapse is generally a random event and does not depend on age. That is analogous to what evolutionary biologists call the
Red Queen hypothesis, which asserts that for a species in a harsh ecology, extinction is a persistent possibility.
Contemporary discussions about societal collapse are seeking resilience by suggesting societal transformation.
Causes of collapse
Because human societies are complex systems, some common factors that may contribute to their decline are economical, environmental, demographic, social and cultural. These factors may
cascade into another and build up to the point that could overwhelm any mechanisms that would otherwise maintain stability. Unexpected and abrupt changes, which experts call
nonlinearities, are some of the warning signs.
In some cases, a natural disaster (such as a tsunami, earthquake,
pandemic
A pandemic ( ) is an epidemic of an infectious disease that has a sudden increase in cases and spreads across a large region, for instance multiple continents or worldwide, affecting a substantial number of individuals. Widespread endemic (epi ...
, massive fire or climate change) may precipitate a collapse. Other factors such as a
Malthusian catastrophe
Malthusianism is a theory that population growth is potentially exponential, according to the Malthusian growth model, while the growth of the food supply or other resources is linear, which eventually reduces living standards to the point of tr ...
,
overpopulation
Overpopulation or overabundance is a state in which the population of a species is larger than the carrying capacity of its environment. This may be caused by increased birth rates, lowered mortality rates, reduced predation or large scale migr ...
, or
resource depletion
Resource depletion occurs when a natural resource is consumed faster than it can be replenished. The value of a resource depends on its availability in nature and the cost of extracting it. By the law of supply and demand, the Scarcity, scarcer ...
might be contributory factors of collapse, but studies of past societies seem to suggest that those factors did not cause the collapse alone. Significant inequity and exposed corruption may combine with lack of loyalty to established political institutions and result in an oppressed lower class rising up and seizing power from a smaller wealthy elite in a
revolution
In political science, a revolution (, 'a turn around') is a rapid, fundamental transformation of a society's class, state, ethnic or religious structures. According to sociologist Jack Goldstone, all revolutions contain "a common set of elements ...
. The diversity of forms that societies evolve corresponds to diversity in their failures.
Jared Diamond
Jared Mason Diamond (born September 10, 1937) is an American scientist, historian, and author. In 1985 he received a MacArthur Genius Grant, and he has written hundreds of scientific and popular articles and books. His best known is '' Guns, G ...
suggests that societies have also collapsed through
deforestation
Deforestation or forest clearance is the removal and destruction of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. Ab ...
, loss of soil fertility, restrictions of trade and/or rising endemic violence.
In the case of the Western Roman Empire, some argued that it did not collapse but merely
transformed.
Natural disasters and climate change
Archeologists have identified signs of a megadrought which lasted for a millennium between 5,000 and 4,000 years ago in Africa and Asia. The drying of the
Green Sahara not only turned it into a desert but also disrupted the monsoon seasons in South and Southeast Asia and caused flooding in East Asia, which prevented successful harvests and the development of complex culture. It coincided with and may have caused the decline and the fall of the
Akkadian Empire
The Akkadian Empire () was the first known empire, succeeding the long-lived city-states of Sumer. Centered on the city of Akkad (city), Akkad ( or ) and its surrounding region, the empire united Akkadian language, Akkadian and Sumerian languag ...
in Mesopotamia and the Indus Valley Civilization. The dramatic shift in climate is known as the
4.2-kiloyear event.
The highly advanced
Indus Valley Civilization
The Indus Valley Civilisation (IVC), also known as the Indus Civilisation, was a Bronze Age civilisation in the northwestern regions of South Asia, lasting from 3300 BCE to 1300 BCE, and in its mature form from 2600 BCE ...
took root around 3000 BC in what is now northwestern India and Pakistan and collapsed around 1700 BC. Since the
Indus script
The Indus script, also known as the Harappan script and the Indus Valley script, is a corpus of symbols produced by the Indus Valley Civilisation. Most inscriptions containing these symbols are extremely short, making it difficult to judge whe ...
has yet to be deciphered, the causes of its de-urbanization
remain a mystery, but there is some evidence pointing to natural disasters. Signs of a gradual decline began to emerge in 1900 BC, and two centuries later, most of the cities had been abandoned. Archeological evidence suggests an increase in interpersonal violence and in infectious diseases like
leprosy
Leprosy, also known as Hansen's disease (HD), is a Chronic condition, long-term infection by the bacteria ''Mycobacterium leprae'' or ''Mycobacterium lepromatosis''. Infection can lead to damage of the Peripheral nervous system, nerves, respir ...
and
tuberculosis
Tuberculosis (TB), also known colloquially as the "white death", or historically as consumption, is a contagious disease usually caused by ''Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can al ...
. Historians and archeologists believe that severe and long-lasting drought and a decline in trade with Egypt and Mesopotamia caused the collapse. Evidence for earthquakes has also been discovered. Sea level changes are also found at two possible seaport sites along the Makran coast which are now inland. Earthquakes may have contributed to decline of several sites by direct shaking damage or by changes in sea level or in water supply.
Volcanic eruptions can abruptly influence the climate. During a large eruption,
sulfur dioxide
Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a colorless gas with a pungent smell that is responsible for the odor of burnt matches. It is r ...
(SO
2) is expelled into the
stratosphere
The stratosphere () is the second-lowest layer of the atmosphere of Earth, located above the troposphere and below the mesosphere. The stratosphere is composed of stratified temperature zones, with the warmer layers of air located higher ...
, where it could stay for years and gradually get oxidized into sulfate aerosols. Being highly reflective, sulfate aerosols reduce the incident sunlight and cool the Earth's surface. By drilling into glaciers and ice sheets, scientists can access the archives of the history of atmospheric composition. A team of multidisciplinary researchers led by Joseph McConnell of the Desert Research Institute in Reno, Nevada deduced that a volcanic eruption occurred in 43 BC, a year after the
assassination of Julius Caesar
Julius Caesar, the Roman dictator, was assassinated on the Ides of March (15 March) 44 BC by a group of senators during a Roman Senate, Senate session at the Curia of Pompey, located within the Theatre of Pompey in Ancient Rome, Rome. The ...
on the Ides of March (15 March) in 44 BC, which left a power vacuum and led to bloody civil wars. According to historical accounts, it was also a period of poor weather, crop failure, widespread famine, and disease. Analyses of tree rings and cave stalagmites from different parts of the globe provided complementary data. The Northern Hemisphere got drier, but the Southern Hemisphere became wetter. Indeed, the Greek historian
Appian
Appian of Alexandria (; ; ; ) was a Greek historian with Roman citizenship who prospered during the reigns of the Roman Emperors Trajan, Hadrian, and Antoninus Pius.
He was born c. 95 in Alexandria. After holding the senior offices in the pr ...
recorded that there was a lack of flooding in Egypt, which also faced famine and pestilence. Rome's interest in Egypt as a source of food intensified, and the aforementioned problems and civil unrest weakened Egypt's ability to resist. Egypt came under Roman rule after
Cleopatra
Cleopatra VII Thea Philopator (; The name Cleopatra is pronounced , or sometimes in both British and American English, see and respectively. Her name was pronounced in the Greek dialect of Egypt (see Koine Greek phonology). She was ...
committed suicide in 30 BC. While it is difficult to say for certain whether Egypt would have become a Roman province if
Okmok volcano (in modern-day Alaska) had not erupted, the eruption likely hastened the process.
More generally, recent research pointed to climate change as a key player in the decline and fall of historical societies in China, the Middle East, Europe, and the Americas. In fact,
paleoclimatogical temperature reconstruction suggests that historical periods of social unrest, societal collapse, and population crash and significant climate change often occurred simultaneously. A team of researchers from Mainland China and Hong Kong were able to establish a causal connection between climate change and large-scale human crises in pre-industrial times. Short-term crises may be caused by social problems, but climate change was the ultimate cause of major crises, starting with economic depressions.
Moreover, since agriculture is highly dependent on climate, any changes to the regional climate from the optimum can induce crop failures.
After around 1130, North America had significant climatic change in the form of a 300-year period of aridity called the
Great Drought. The
Mississippian culture
The Mississippian culture was a collection of Native American societies that flourished in what is now the Midwestern, Eastern, and Southeastern United States from approximately 800 to 1600 CE, varying regionally. It was known for building la ...
collapsed during this period. The
Ancestral Puebloans
The Ancestral Puebloans, also known as Ancestral Pueblo peoples or the Basketmaker-Pueblo culture, were an ancient Native American culture of Pueblo peoples spanning the present-day Four Corners region of the United States, comprising southe ...
left their established homes in the 12th and 13th centuries. Current scholarly consensus is that Ancestral Puebloans responded to pressure from
Numic-speaking peoples moving onto the Colorado Plateau, as well as climate change that resulted in agricultural failures.
The Mongol conquests corresponded to a period of cooling in the Northern Hemisphere between the thirteenth and fourteenth centuries, when the
Medieval Warm Period
The Medieval Warm Period (MWP), also known as the Medieval Climate Optimum or the Medieval Climatic Anomaly, was a time of warm climate in the North Atlantic region that lasted from about to about . Climate proxy records show peak warmth occu ...
was giving way to the Little Ice Age, which caused ecological stress. In Europe, the cooling climate did not directly facilitate the
Black Death
The Black Death was a bubonic plague pandemic that occurred in Europe from 1346 to 1353. It was one of the list of epidemics, most fatal pandemics in human history; as many as people perished, perhaps 50% of Europe's 14th century population. ...
, but it caused wars, mass migration, and famine, which helped diseases spread.

A more recent example is the
General Crisis of the Seventeenth Century in Europe, which was a period of inclement weather, crop failure, economic hardship, extreme intergroup violence, and high mortality because of the
Little Ice Age
The Little Ice Age (LIA) was a period of regional cooling, particularly pronounced in the North Atlantic region. It was not a true ice age of global extent. The term was introduced into scientific literature by François E. Matthes in 1939. Mat ...
. The
Maunder Minimum involved
sunspots being exceedingly rare. Episodes of social instability track the cooling with a time lag of up to 15 years, and many developed into armed conflicts, such as the
Thirty Years' War
The Thirty Years' War, fought primarily in Central Europe between 1618 and 1648, was one of the most destructive conflicts in History of Europe, European history. An estimated 4.5 to 8 million soldiers and civilians died from battle, famine ...
(1618–1648),
which started as a war of succession to the Bohemian throne. Animosity between Protestants and Catholics in the
Holy Roman Empire
The Holy Roman Empire, also known as the Holy Roman Empire of the German Nation after 1512, was a polity in Central and Western Europe, usually headed by the Holy Roman Emperor. It developed in the Early Middle Ages, and lasted for a millennium ...
(in modern-day Germany) added fuel to the fire. Soon, it escalated to a huge conflict that involved all major European powers and devastated much of Germany. When the war had ended, some regions of the empire had seen their populations drop by as much as 70%.
[See the end of the section ' Demographic dynamics' for a chart of the death rate (per 100,000) of the Thirty Years' War compared to other armed conflicts between 1400 and 2000.] However, not all societies faced crises during this period. Tropical countries with high carrying capacities and trading economies did not suffer much because the changing climate did not induce an economic depression in those places.
Foreign invasions and mass migration
Between ca. 4000 and 3000 BCE,
neolithic populations in western Eurasia declined, probably due to the plague and other viral hemorrhagic fevers. This decline was followed by the
Indo-European migrations
The Indo-European migrations are hypothesized migrations of Proto-Indo-Europeans, peoples who spoke Proto-Indo-European language, Proto-Indo-European (PIE) and the derived Indo-European languages, which took place from around 4000 to 1000 BCE, ...
. Around 3,000 BC, people of the pastoralist
Yamnaya culture
The Yamnaya ( ) or Yamna culture ( ), also known as the Pit Grave culture or Ochre Grave culture, is a late Copper Age to early Bronze Age archaeological culture of the region between the Southern Bug, Dniester, and Ural rivers (the Pontic–C ...
from the
Pontic–Caspian steppe
The Pontic–Caspian Steppe is a steppe extending across Eastern Europe to Central Asia, formed by the Caspian and Pontic steppes. It stretches from the northern shores of the Black Sea (the ''Pontus Euxinus'' of antiquity) to the northern a ...
, who had high levels of
WSH ancestry, embarked on a massive expansion throughout Eurasia, which is considered to be associated with the dispersal of the
Indo-European languages
The Indo-European languages are a language family native to the northern Indian subcontinent, most of Europe, and the Iranian plateau with additional native branches found in regions such as Sri Lanka, the Maldives, parts of Central Asia (e. ...
by most contemporary linguists, archaeologists, and geneticists. The expansion of WSHs resulted in the virtual disappearance of the Y-DNA of
Early European Farmers (EEFs) from the European gene pool, significantly altering the cultural and genetic landscape of Europe. EEF mtDNA however remained frequent, suggesting admixture between WSH males and EEF females.
A mysterious loose confederation of fierce maritime marauders known as the
Sea Peoples
The Sea Peoples were a group of tribes hypothesized to have attacked Ancient Egypt, Egypt and other Eastern Mediterranean regions around 1200 BC during the Late Bronze Age. The hypothesis was proposed by the 19th-century Egyptology, Egyptologis ...
was identified as one of the main causes of the
Late Bronze Age Collapse
The Late Bronze Age collapse was a period of societal collapse in the Mediterranean basin during the 12th century BC. It is thought to have affected much of the Eastern Mediterranean and Near East, in particular Egypt, Anatolia, the Aegea ...
in the Eastern Mediterranean. It is possible that the Sea Peoples were themselves victims of the environmental changes that led to widespread famine and precipitated the Collapse.

In the third century BC, a Eurasian nomadic people, the
Xiongnu
The Xiongnu (, ) were a tribal confederation of Nomad, nomadic peoples who, according to ancient Chinese historiography, Chinese sources, inhabited the eastern Eurasian Steppe from the 3rd century BC to the late 1st century AD. Modu Chanyu, t ...
, began threatening China's frontiers, but by the first century BC, they had been completely expelled. They then turned their attention westward and displaced various other tribes in Eastern and Central Europe, which led to a cascade of events.
Attila
Attila ( or ; ), frequently called Attila the Hun, was the ruler of the Huns from 434 until his death in early 453. He was also the leader of an empire consisting of Huns, Ostrogoths, Alans, and Gepids, among others, in Central Europe, C ...
rose to power as leader of the
Huns
The Huns were a nomadic people who lived in Central Asia, the Caucasus, and Eastern Europe between the 4th and 6th centuries AD. According to European tradition, they were first reported living east of the Volga River, in an area that was par ...
and initiated a campaign of invasions and looting and went as far as
Gaul
Gaul () was a region of Western Europe first clearly described by the Roman people, Romans, encompassing present-day France, Belgium, Luxembourg, and parts of Switzerland, the Netherlands, Germany, and Northern Italy. It covered an area of . Ac ...
(modern-day France). Attila's Huns were clashing with the Roman Empire, which had already been divided into two-halves for ease of administration: the
Eastern Roman Empire
The Byzantine Empire, also known as the Eastern Roman Empire, was the continuation of the Roman Empire centred on Constantinople during late antiquity and the Middle Ages. Having survived the events that caused the fall of the Western Roman E ...
and the
Western Roman Empire
In modern historiography, the Western Roman Empire was the western provinces of the Roman Empire, collectively, during any period in which they were administered separately from the eastern provinces by a separate, independent imperial court. ...
. Despite managing to stop Attila at the
Battle of Chalons
The Battle of the Catalaunian Plains (or Fields), also called the Battle of the Campus Mauriacus, Battle of Châlons, Battle of Troyes or the Battle of Maurica, took place on June 20, 451 AD, between a victorious coalition, led by the Wester ...
in 451 AD, the Romans were unable to prevent Attila from attacking
Roman Italy
Roman Italy is the period of ancient Italian history going from the founding of Rome, founding and Roman expansion in Italy, rise of ancient Rome, Rome to the decline and fall of the Western Roman Empire; the Latin name of the Italian peninsula ...
the next year. Northern Italian cities like
Milan
Milan ( , , ; ) is a city in northern Italy, regional capital of Lombardy, the largest city in Italy by urban area and the List of cities in Italy, second-most-populous city proper in Italy after Rome. The city proper has a population of nea ...
were ravaged. The Huns never again posed a threat to the Romans after Attila's death, but the rise of the Huns also forced the
Germanic peoples
The Germanic peoples were tribal groups who lived in Northern Europe in Classical antiquity and the Early Middle Ages. In modern scholarship, they typically include not only the Roman-era ''Germani'' who lived in both ''Germania'' and parts of ...
out of their territories and made those groups press their way into parts of France, Spain, Italy, and even as far south as North Africa. The city of Rome itself came under attack by the
Visigoths
The Visigoths (; ) were a Germanic people united under the rule of a king and living within the Roman Empire during late antiquity. The Visigoths first appeared in the Balkans, as a Roman-allied Barbarian kingdoms, barbarian military group unite ...
in
410 and was plundered by the
Vandals
The Vandals were a Germanic people who were first reported in the written records as inhabitants of what is now Poland, during the period of the Roman Empire. Much later, in the fifth century, a group of Vandals led by kings established Vand ...
in
455.
[The Vandals thus made themselves the origin of the modern English word ']vandalism
Vandalism is the action involving deliberate destruction of or damage to public or private property.
The term includes property damage, such as graffiti and defacement directed towards any property without permission of the owner. The t ...
'. A combination of internal strife, economic weakness, and relentless invasions by the Germanic peoples pushed the Western Roman Empire into
terminal decline. The last Western Roman Emperor,
Romulus Augustulus
Romulus Augustus (after 511), nicknamed Augustulus, was Roman emperor of the Western Roman Empire, West from 31 October 475 until 4 September 476. Romulus was placed on the imperial throne while still a minor by his father Orestes (father of Ro ...
, was
dethroned in 476 by the German
Odoacer
Odoacer ( – 15 March 493 AD), also spelled Odovacer or Odovacar, was a barbarian soldier and statesman from the Middle Danube who deposed the Western Roman child emperor Romulus Augustulus and became the ruler of Italy (476–493). Odoacer' ...
, who declared himself
King of Italy
King is a royal title given to a male monarch. A king is an absolute monarch if he holds unrestricted governmental power or exercises full sovereignty over a nation. Conversely, he is a constitutional monarch if his power is restrained by ...
.
In the eleventh century AD,
North Africa
North Africa (sometimes Northern Africa) is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region. However, it is sometimes defined as stretching from the Atlantic shores of t ...
's populous and flourishing civilization collapsed after it had exhausted its resources in internal fighting and suffering devastation from the invasion of the
Bedouin
The Bedouin, Beduin, or Bedu ( ; , singular ) are pastorally nomadic Arab tribes who have historically inhabited the desert regions in the Arabian Peninsula, North Africa, the Levant, and Mesopotamia (Iraq). The Bedouin originated in the Sy ...
tribes of
Banu Sulaym
The Banu Sulaym () is an Arab tribe that dominated part of the Hejaz in the pre-Islamic era. They maintained close ties with the Quraysh of Mecca and the inhabitants of Medina, and fought in a number of battles against the Islamic prophet Muha ...
and
Banu Hilal
The Banu Hilal () was a confederation of Arab tribes from the Najd region of the central Arabian Peninsula that emigrated to the Maghreb region of North Africa in the 11th century. They ruled the Najd, and campaigned in the borderlands between I ...
.
Ibn Khaldun
Ibn Khaldun (27 May 1332 – 17 March 1406, 732–808 Hijri year, AH) was an Arabs, Arab Islamic scholar, historian, philosopher and sociologist. He is widely acknowledged to be one of the greatest social scientists of the Middle Ages, and cons ...
noted that all of the lands ravaged by Banu Hilal invaders had become arid desert.

In 1206, a warlord achieved dominance over all Mongols with the title
Genghis Khan
Genghis Khan (born Temüjin; August 1227), also known as Chinggis Khan, was the founder and first khan (title), khan of the Mongol Empire. After spending most of his life uniting the Mongols, Mongol tribes, he launched Mongol invasions and ...
and began his campaign of territorial expansion. The Mongols' highly flexible and mobile cavalry enabled them to conquer their enemies with efficiency and swiftness. In the brutal pillaging that followed
Mongol invasions during the thirteenth and fourteenth centuries, the invaders decimated the populations of China, Russia, the Middle East, and
Islamic Central Asia. Later Mongol leaders, such as
Timur
Timur, also known as Tamerlane (1320s17/18 February 1405), was a Turco-Mongol conqueror who founded the Timurid Empire in and around modern-day Afghanistan, Iran, and Central Asia, becoming the first ruler of the Timurid dynasty. An undefeat ...
, destroyed many cities, slaughtered thousands of people, and irreparably damaged the ancient irrigation systems of
Mesopotamia
Mesopotamia is a historical region of West Asia situated within the Tigris–Euphrates river system, in the northern part of the Fertile Crescent. Today, Mesopotamia is known as present-day Iraq and forms the eastern geographic boundary of ...
. The invasions transformed a settled society to a nomadic one. In China, for example, a combination of war, famine, and pestilence during the Mongol conquests halved the population, a decline of around 55 million people.
The Mongols also displaced large numbers of people and created power vacuums. The
Khmer Empire
The Khmer Empire was an empire in Southeast Asia, centered on Hydraulic empire, hydraulic cities in what is now northern Cambodia. Known as Kambuja (; ) by its inhabitants, it grew out of the former civilization of Chenla and lasted from 802 t ...
went into decline and was replaced by the Thais, who were pushed southward by the Mongols. The Vietnamese, who succeeded in defeating the Mongols, also turned their attention to the south and by 1471 began to subjugate the
Chams
The Chams ( Cham: , چام, ''cam''), or Champa people ( Cham: , اوراڠ چمڤا, ''Urang Campa''; or ; , ), are an Austronesian ethnic group in Southeast Asia and are the original inhabitants of central Vietnam and coastal Cambodia be ...
. When Vietnam's
Later Lê dynasty went into decline in the late 1700s, a
bloody civil war erupted between the Trịnh family in the north and the Nguyễn family in the south.
[North and South here are with respect to the Gianh River, which is close to the Bến Hải River, or approximately the 17th Parallel, used for the Partition of Vietnam after the First Indochinese War and before the Second Indochinese War, commonly known as the ]Vietnam War
The Vietnam War (1 November 1955 – 30 April 1975) was an armed conflict in Vietnam, Laos, and Cambodia fought between North Vietnam (Democratic Republic of Vietnam) and South Vietnam (Republic of Vietnam) and their allies. North Vietnam w ...
. More Cham provinces were seized by the Nguyễn warlords.
Finally, Nguyễn Ánh emerged victorious and declared himself Emperor of Vietnam (changing the name from Annam) with the title
Gia Long
Gia Long (Chữ Hán, Chữ hán: 嘉隆) ( (''Hanoi, North''), (''Ho Chi Minh City, South''); 8 February 1762 – 3 February 1820), born Nguyễn Phúc Ánh (阮福暎) or Nguyễn Ánh (阮暎), was the founding emperor of the Nguyễn dynas ...
and established the Nguyễn dynasty. The last remaining principality of Champa, Panduranga (modern-day
Phan Rang Phan may refer to:
* Phan (surname), a Vietnamese family name
* Phan District, Chiang Rai Province, Thailand
* Phan River
The Phan River () is a river of Bình Thuận Province, Vietnam.Vietnam Administrative Atlas, NXB Bản Đồ, 2004 It flo ...
, Vietnam), survived until 1832, when Emperor
Minh Mạng
Minh Mạng (), also known as Minh Mệnh (, vi-hantu, 明 命, lit. "the bright favour of Heaven"; 25 May 1791 – 20 January 1841; born Nguyễn Phúc Đảm, also known as Nguyễn Phúc Kiểu), was the second emperor of the Nguyễ ...
(Nguyễn Phúc Đảm) conquered it after centuries of
Cham–Vietnamese wars. Vietnam's policy of assimilation involved the forcefeeding of pork to Muslims and beef to Hindus, which fueled resentment. An
uprising followed, the first and only war between Vietnam and the jihadists, until it was crushed.
Famine, economic depression, and internal strife
Around 1210 BC, the
New Kingdom of Egypt
The New Kingdom, also called the Egyptian Empire, refers to ancient Egypt between the 16th century BC and the 11th century BC. This period of History of ancient Egypt, ancient Egyptian history covers the Eighteenth Dynasty of Egypt, Eighteenth, ...
shipped large amounts of grain to the disintegrating Hittite Empire. Thus, there had been a food shortage in Anatolia but not the Nile Valley.
However, that soon changed. Although Egypt managed to deliver a decisive and final defeat to the
Sea Peoples
The Sea Peoples were a group of tribes hypothesized to have attacked Ancient Egypt, Egypt and other Eastern Mediterranean regions around 1200 BC during the Late Bronze Age. The hypothesis was proposed by the 19th-century Egyptology, Egyptologis ...
at the
Battle of Xois, Egypt itself went into steep decline. The
collapse of all other societies in the Eastern Mediterranean disrupted established trade routes and caused widespread economic depression. Government workers became underpaid, which resulted in the first labor strike in recorded history and undermined royal authority.
There was also political infighting between different factions of government. Bad harvest from the reduced flooding at the Nile led to a major famine. Food prices rose to eight times their normal values and occasionally even reached twenty-four times. Runaway
inflation
In economics, inflation is an increase in the average price of goods and services in terms of money. This increase is measured using a price index, typically a consumer price index (CPI). When the general price level rises, each unit of curre ...
followed. Attacks by the Libyans and Nubians made things even worse. Throughout the
Twentieth Dynasty (~1187–1064 BC), Egypt devolved from a major power in the Mediterranean to a deeply divided and weakened state, which later came to be ruled by the Libyans and the Nubians.
Between 481 BC and 221 BC, the
Period of the Warring States in China ended by King Zheng of the Qin dynasty succeeding in
defeating six competing factions and thus becoming the first Chinese emperor, titled
Qin Shi Huang
Qin Shi Huang (, ; February 25912 July 210 BC), born Ying Zheng () or Zhao Zheng (), was the founder of the Qin dynasty and the first emperor of China. He is widely regarded as the first ever supreme leader of a unitary state, unitary d ...
. A ruthless but efficient ruler, he raised a disciplined and professional army and introduced a significant number of reforms, such as unifying the language and creating a single currency and system of measurement. In addition, he funded dam constructions and began building the first segment of what was to become the
Great Wall of China
The Great Wall of China (, literally "ten thousand ''li'' long wall") is a series of fortifications in China. They were built across the historical northern borders of ancient Chinese states and Imperial China as protection against vario ...
to defend his realm against northern nomads. Nevertheless, internal feuds and rebellions made his empire fall apart after his death in 210 B.C.

In the early fourteenth century AD, Britain suffered repeated rounds of crop failures from unusually heavy rainfall and flooding. Much livestock either starved or drowned. Food prices skyrocketed, and King Edward II attempted to rectify the situation by imposing price controls, but vendors simply refused to sell at such low prices. In any case, the act was abolished by the Lincoln Parliament in 1316. Soon, people from commoners to nobles were finding themselves short of food. Many resorted to begging, crime, and eating animals they otherwise would not eat. People in northern England had to deal with raids from Scotland. There were even reports of
cannibalism
Cannibalism is the act of consuming another individual of the same species as food. Cannibalism is a common ecological interaction in the animal kingdom and has been recorded in more than 1,500 species. Human cannibalism is also well document ...
.
In Continental Europe, things were at least just as bad. The
Great Famine of 1315–1317
The Great Famine of 1315–1317 (occasionally dated 1315–1322) was the first of a series of large-scale crises that struck parts of Europe early in the 14th century. Most of Europe (extending east to Poland and south to the Alps) was affected ...
coincided with the end of the
Medieval Warm Period
The Medieval Warm Period (MWP), also known as the Medieval Climate Optimum or the Medieval Climatic Anomaly, was a time of warm climate in the North Atlantic region that lasted from about to about . Climate proxy records show peak warmth occu ...
and the start of the Little Ice Age. Some historians suspect that the change in climate was due to
Mount Tarawera in New Zealand erupting in 1314.
The Great Famine was, however, only one of the calamities striking Europe that century, as the Hundred Years' War and Black Death would soon follow.
(Also see the
Crisis of the Late Middle Ages.) Recent analysis of
tree rings complement historical records and show that the summers of 1314–1316 were some of the wettest on record over a period of 700 years.
Disease outbreaks

Historically, the dawn of agriculture led to the rise of contagious diseases.
Compared to their hunting-gathering counterparts, agrarian societies tended to be sedentary, have higher population densities, be in frequent contact with livestock, and be more exposed to contaminated water supplies and higher concentrations of garbage. Poor sanitation, a lack of medical knowledge, superstitions, and sometimes a combination of disasters exacerbated the problem.
The journalist Michael Rosenwald wrote that "history shows that past pandemics have reshaped societies in profound ways. Hundreds of millions of people have died. Empires have fallen. Governments have cracked. Generations have been annihilated."
From the description of symptoms by the Greek physician
Galen
Aelius Galenus or Claudius Galenus (; September 129 – AD), often Anglicization, anglicized as Galen () or Galen of Pergamon, was a Ancient Rome, Roman and Greeks, Greek physician, surgeon, and Philosophy, philosopher. Considered to be one o ...
, which included coughing, fever, (blackish) diarrhea, swollen throat, and thirst, modern experts identified the probable culprits of the
Antonine Plague (165–180 AD) to have been
smallpox
Smallpox was an infectious disease caused by Variola virus (often called Smallpox virus), which belongs to the genus '' Orthopoxvirus''. The last naturally occurring case was diagnosed in October 1977, and the World Health Organization (W ...
or
measles
Measles (probably from Middle Dutch or Middle High German ''masel(e)'', meaning "blemish, blood blister") is a highly contagious, Vaccine-preventable diseases, vaccine-preventable infectious disease caused by Measles morbillivirus, measles v ...
.
The disease likely started in China and spread to the West via the
Silk Road
The Silk Road was a network of Asian trade routes active from the second century BCE until the mid-15th century. Spanning over , it played a central role in facilitating economic, cultural, political, and religious interactions between the ...
. Roman troops first contracted the disease in the East before they returned home. Striking a virgin population, the Antonine Plague had dreadful mortality rates; between one third to half of the population, 60 to 70 million people, perished. Roman cities suffered from a combination of overcrowding, poor hygiene, and unhealthy diets. They quickly became epicenters. Soon, the disease reached as far as Gaul and mauled Roman defenses along the Rhine. The ranks of the previously formidable Roman army had to be filled with freed slaves, German mercenaries, criminals, and gladiators. That ultimately failed to prevent the Germanic tribes from crossing the Rhine. On the civilian side, the Antonine Plague created drastic shortages of businessmen, which disrupted trade, and farmers, which led to a food crisis. An economic depression followed and government revenue fell. Some accused Emperor
Marcus Aurelius
Marcus Aurelius Antoninus ( ; ; 26 April 121 – 17 March 180) was Roman emperor from 161 to 180 and a Stoicism, Stoic philosopher. He was a member of the Nerva–Antonine dynasty, the last of the rulers later known as the Five Good Emperors ...
and Co-Emperor
Lucius Verus
Lucius Aurelius Verus (; 15 December 130 – 23 January 169) was Roman emperor from 161 until his death in 169, alongside his adoptive brother Marcus Aurelius. He was a member of the Nerva–Antonine dynasty. Verus' succession together with Ma ...
, both of whom victims of the disease, of affronting the
gods
A deity or god is a supernatural being considered to be sacred and worthy of worship due to having authority over some aspect of the universe and/or life. The ''Oxford Dictionary of English'' defines ''deity'' as a God (male deity), god or god ...
, but others blamed Christians. However, the Antonine Plague strengthened the position of the monotheistic religion of
Christianity
Christianity is an Abrahamic monotheistic religion, which states that Jesus in Christianity, Jesus is the Son of God (Christianity), Son of God and Resurrection of Jesus, rose from the dead after his Crucifixion of Jesus, crucifixion, whose ...
in the formerly-polytheistic society, as Christians won public admiration for their good works. Ultimately the Roman army, the Roman cities, the size of the empire and its trade routes, which were required for Roman power and influence to exist, facilitated the spread of the disease. The Antonine Plague is considered by some historians as a useful starting point for understanding the decline and fall of the Western Roman Empire. It was followed by the
Plague of Cyprian
The Plague of Cyprian was a pandemic which afflicted the Roman Empire from about AD 249 to 262, or 251/2 to 270. The plague is thought to have caused widespread manpower shortages for food production and the Roman army, severely weakening the em ...
(249–262 AD) and the Plague of Justinian (541-542). Together, they cracked the foundations of the Roman Empire.
In the sixth century AD, while the Western Roman Empire had already succumbed to attacks by the Germanic tribes, the Eastern Roman Empire stood its ground. In fact, a peace treaty with the Persians allowed Emperor
Justinian the Great to concentrate on recapturing territories belonging to the Western Empire. His generals,
Belisarius
BelisariusSometimes called Flavia gens#Later use, Flavius Belisarius. The name became a courtesy title by the late 4th century, see (; ; The exact date of his birth is unknown. March 565) was a military commander of the Byzantine Empire under ...
and
Narses
Narses (also spelled Nerses; ; ; ; c. 478–573) was a distinguished Byzantine general and statesman of Armenian heritage, renowned for his critical role in Emperor Justinian I’s military campaigns. Alongside the famed Belisarius, Narses was ...
, achieved a number of important victories against the Ostrogoths and the Vandals. However, their hope of keeping the Western Empire was dashed by the arrival of what became known as the
Plague of Justinian
The plague of Justinian or Justinianic plague (AD 541–549) was an epidemic of Plague (disease), plague that afflicted the entire Mediterranean basin, Mediterranean Basin, Europe, and the Near East, especially the Sasanian Empire and the Byza ...
(541-542). According to the Byzantine historian
Procopius of Caesarea
Procopius of Caesarea (; ''Prokópios ho Kaisareús''; ; – 565) was a prominent late antique Greek scholar and historian from Caesarea Maritima. Accompanying the Roman general Belisarius in Emperor Justinian's wars, Procopius became the pr ...
, the epidemic originated in China and Northeastern India and reached the Eastern Roman Empire via trade routes terminating in the Mediterranean. Modern scholarship has deduced that the epidemic was caused by the bacterium ''
Yersinia pestis
''Yersinia pestis'' (''Y. pestis''; formerly ''Pasteurella pestis'') is a Gram-negative bacteria, gram-negative, non-motile bacteria, non-motile, coccobacillus Bacteria, bacterium without Endospore, spores. It is related to pathogens ''Yer ...
'', the same one that would later bring the Black Death, the single deadliest pandemic in human history, but how many actually died from it remains uncertain. Current estimates put the figure between thirty and fifty million people,
a significant portion of the human population at that time.
The Plague arguably cemented the fate of Rome.
The epidemic also devastated the
Sasanian Empire
The Sasanian Empire (), officially Eranshahr ( , "Empire of the Iranian peoples, Iranians"), was an List of monarchs of Iran, Iranian empire that was founded and ruled by the House of Sasan from 224 to 651. Enduring for over four centuries, th ...
in Persia. Caliph
Abu Bakr
Abd Allah ibn Abi Quhafa (23 August 634), better known by his ''Kunya (Arabic), kunya'' Abu Bakr, was a senior Sahaba, companion, the closest friend, and father-in-law of Muhammad. He served as the first caliph of the Rashidun Caliphate, ruli ...
seized the opportunity to launch military campaigns that
overran the Sassanians and captured Roman-held territories in the Caucasus, the Levant, Egypt, and elsewhere in North Africa. Before the Justinian Plague, the Mediterranean world had been commercially and culturally stable. After the Plague, it fractured into a trio of civilizations battling for power: the Islamic Civilization, the Byzantine Empire, and what later became known as Medieval Europe. With so many people dead, the supply of workers, many of whom were slaves, was critically short. Landowners had no choice but to lend pieces of land to serfs to work the land in exchange for military protection and other privileges. That sowed the seeds of
feudalism
Feudalism, also known as the feudal system, was a combination of legal, economic, military, cultural, and political customs that flourished in Middle Ages, medieval Europe from the 9th to 15th centuries. Broadly defined, it was a way of struc ...
.

There is evidence that the Mongol expeditions may have spread the
bubonic plague
Bubonic plague is one of three types of Plague (disease), plague caused by the Bacteria, bacterium ''Yersinia pestis''. One to seven days after exposure to the bacteria, flu-like symptoms develop. These symptoms include fever, headaches, and ...
across much of Eurasia, which helped to spark the
Black Death
The Black Death was a bubonic plague pandemic that occurred in Europe from 1346 to 1353. It was one of the list of epidemics, most fatal pandemics in human history; as many as people perished, perhaps 50% of Europe's 14th century population. ...
of the early fourteenth century.
The Italian historian
Gabriele de’ Mussi wrote that the Mongols catapulted the corpses of those who contracted the plague into Caffa (now
Feodossia, Crimea) during
the siege of that city and that soldiers who were transported from there brought the plague to Mediterranean ports. However, that account of the origin of the Black Death in Europe remains controversial, though plausible, because of the complex epidemiology of the plague. Modern epidemiologists do not believe that the Black Death had a single source of spreading into Europe. Research into the past on this topic is further complicated by politics and the passage of time. It is difficult to distinguish between natural epidemics and biological warfare, both of which are common throughout human history.
Biological weapons are economical because they turn an enemy casualty into a delivery system and so were favored in armed conflicts of the past. Furthermore, more soldiers died of disease than in combat until recently.
[For example, during the ]Napoleonic Wars
{{Infobox military conflict
, conflict = Napoleonic Wars
, partof = the French Revolutionary and Napoleonic Wars
, image = Napoleonic Wars (revision).jpg
, caption = Left to right, top to bottom:Battl ...
, for every British soldier who got killed in action, eight died of disease. During the American Civil War
The American Civil War (April 12, 1861May 26, 1865; also known by Names of the American Civil War, other names) was a civil war in the United States between the Union (American Civil War), Union ("the North") and the Confederate States of A ...
, two-thirds of the almost 700,000 dead were victims of smallpox, dysentery, typhoid, malaria, and pneumonia, collectively referred to as the "Third Army". In any case, by the 1340s, Black Death killed 200 million people.
The widening trade routes in the Late Middle Ages helped the plague spread rapidly.
It took the European population more than two centuries to return to its level before the pandemic.
Consequently, it destabilized most of society and likely undermined feudalism and the authority of the Church.
With labor in short supply, workers' bargaining power increased dramatically. Various inventions that reduced the cost of labor, saved time, and raised productivity, such as the three-field crop rotation system, the iron plow, the use of manure to fertilize the soil, and the water pumps, were widely adopted. Many former serfs, now free from feudal obligations, relocated to the cities and changed profession to crafts and trades. The more successful ones became the new middle class. Trade flourished as demands for a myriad of consumer goods rose. Society became wealthier and could afford to fund the arts and the sciences.

Encounters between European explorers and Native Americans exposed the latter to a variety of diseases of extraordinary virulence. Having migrated from Northeastern Asia 15,000 years ago, Native Americans had not been introduced to the plethora of contagious diseases that emerged after the rise of agriculture in the Old World. As such, they had immune systems that were ill-equipped to handle the diseases to which their counterparts in Eurasia had become resistant. When the Europeans arrived in the Americas, in short order, the indigenous populations of the Americas found themselves facing smallpox,
measles
Measles (probably from Middle Dutch or Middle High German ''masel(e)'', meaning "blemish, blood blister") is a highly contagious, Vaccine-preventable diseases, vaccine-preventable infectious disease caused by Measles morbillivirus, measles v ...
,
whooping cough
Whooping cough ( or ), also known as pertussis or the 100-day cough, is a highly contagious, Vaccine-preventable diseases, vaccine-preventable Pathogenic bacteria, bacterial disease. Initial symptoms are usually similar to those of the common c ...
, and the bubonic plague, among others. In tropical areas, malaria,
yellow fever,
dengue fever
Dengue fever is a mosquito-borne disease caused by dengue virus, prevalent in tropical and subtropical areas. Asymptomatic infections are uncommon, mild cases happen frequently; if symptoms appear, they typically begin 3 to 14 days after i ...
,
river blindness
Onchocerciasis, also known as river blindness, is a disease caused by infection with the parasitic worm ''Onchocerca volvulus''. Symptoms include severe itching, bumps under the skin, and blindness. It is the second-most common cause of blindne ...
, and others appeared. Most of these tropical diseases were traced to Africa.
Smallpox ravaged Mexico in the 1520s and killed 150,000 in
Tenochtitlán alone, including the emperor, and Peru in the 1530s, which aided the European conquerors. A combination of Spanish military attacks and evolutionarily novel diseases finished off the Aztec Empire in the sixteenth century.
It is commonly believed that the death of as much as 90% or 95% of the
Native American population of the
New World
The term "New World" is used to describe the majority of lands of Earth's Western Hemisphere, particularly the Americas, and sometimes Oceania."America." ''The Oxford Companion to the English Language'' (). McArthur, Tom, ed., 1992. New York: ...
was caused by
Old World
The "Old World" () is a term for Afro-Eurasia coined by Europeans after 1493, when they became aware of the existence of the Americas. It is used to contrast the continents of Africa, Europe, and Asia in the Eastern Hemisphere, previously ...
diseases,
though new research suggests
tuberculosis
Tuberculosis (TB), also known colloquially as the "white death", or historically as consumption, is a contagious disease usually caused by ''Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can al ...
from seals and sea lions played a significant part.

Similar events took place in Oceania and Madagascar.
Smallpox was externally brought to Australia. The first recorded outbreak, in 1789, devastated the
Aboriginal population. The extent of the outbreak is disputed, but some sources claim that it killed about 50% of coastal Aboriginal populations on the east coast. There is an ongoing historical debate concerning two rival and irreconcilable theories about how the disease first entered the continent (see
History of smallpox). Smallpox continued to be a deadly disease and killed an estimated 300 million people in the twentieth century alone, but a vaccine, the first of any kind, had been available since 1796.
As humans spread around the globe, human societies flourish and become more dependent on trade, and because urbanization means that people leave sparsely-populated rural areas for densely-populated neighborhoods, infectious diseases spread much more easily. Outbreaks are frequent, even in the modern era, but medical advances have been able to alleviate their impacts.
In fact, the human population grew tremendously in the twentieth century, as did the population of farm animals, from which diseases could
jump to humans, but in the developed world and increasingly also in the developing world, people are less likely to fall victim to infectious diseases than ever before. For instance, the advent of antibiotics, starting with
penicillin
Penicillins (P, PCN or PEN) are a group of beta-lactam antibiotic, β-lactam antibiotics originally obtained from ''Penicillium'' Mold (fungus), moulds, principally ''Penicillium chrysogenum, P. chrysogenum'' and ''Penicillium rubens, P. ru ...
in 1928, has resulted in the saving of the lives of hundreds of millions of people suffering from bacterial infections. However, there is no guarantee that would continue because bacteria are becoming increasingly
resistant to antibiotics, and doctors and public health experts such as former Chief Medical Officer for England
Sally Davies have even warned of an incoming "antibiotic apocalypse". The World Health Organization warned in 2019 that the spread of vaccine scepticism has been accompanied by the resurrection of long-conquered diseases like measles. This led the WHO to name the antivaccination movement one of the world's top 10 public-health threats.
Institutional unemployment
During the Roman Empire, citizen employment was vastly being replaced by slave labor. Slaves were replacing many of the jobs citizens were doing. Slaves were receiving apprenticeships and education and were even learning to replace the jobs of skilled craftsman.
Since slaves do not pay taxes and were replacing most jobs from citizens, this reduced the revenue the state could accrue from their citizens.
This high level of unemployment also led to high levels of poverty, which reduced demand for businesses relying on slave labor.
As taxes fell, so did government revenue. To compensate for this economic slowdown and mitigate the high levels of poverty, the Roman government implemented a form of welfare called the
dole, providing citizens free money and free grain.
Paying for the dole required high levels of government spending, exacerbating the Roman debt and also producing inflation. With slavery replacing most labor, tax revenues also plummeted, further exacerbating the government's debt.
To pay off the enormous debt, the Romans began to devalue the currency and produce more coinage. Eventually, this overwhelmed the Roman Empire and partially contributed to its collapse.
Demographic dynamics
Several key features of human societal collapse can be related to population dynamics. For example, the native population of Cusco, Peru at the time of the Spanish conquest was stressed by an imbalanced
sex ratio
A sex ratio is the ratio of males to females in a population. As explained by Fisher's principle, for evolutionary reasons this is typically about 1:1 in species which reproduce sexually. However, many species deviate from an even sex ratio, ei ...
.
There is strong evidence that humans also display
population cycles. Societies as diverse as those of England and France during the Roman, medieval, and early modern eras, of Egypt during Greco-Roman and Ottoman rule, and of various dynasties in China all showed similar patterns of political instability and violence becoming considerably more common after times of relative peace, prosperity, and sustained population growth. Quantitatively, periods of unrest included many times more events of instability per decade and occurred when the population was declining, rather than increasing. Pre-industrial agrarian societies typically faced instability after one or two centuries of stability. However, a population approaching its
carrying capacity
The carrying capacity of an ecosystem is the maximum population size of a biological species that can be sustained by that specific environment, given the food, habitat, water, and other resources available. The carrying capacity is defined as the ...
alone is not enough to trigger general decline if the people remained united and the ruling class strong. Other factors had to be involved, such as having more aspirants for positions of the elite than the society could realistically support (
elite overproduction), which led to social strife, and chronic inflation, which caused incomes to fall and threatened the fiscal health of the state.
In particular, an excess in especially young adult male population predictably led to social unrest and violence, as the third and higher-order parity sons had trouble realizing their economic desires and became more open to extreme ideas and actions.
Adults in their 20s are especially prone to radicalization. Most historical periods of social unrest lacking in external triggers, such as natural calamities, and most genocides can be readily explained as a result of a built-up youth bulge.
As those trends intensified, they jeopardized the social fabric, which facilitated the decline.
Theories
Historical theories have evolved from being purely social and ethical, to ideological and ethnocentric, and finally to multidisciplinary studies. They have become much more sophisticated.
Cognitive decline and loss of creativity
The anthropologist
Joseph Tainter theorized that collapsed societies essentially exhausted their own designs and were unable to adapt to natural
diminishing returns
In economics, diminishing returns means the decrease in marginal (incremental) output of a production process as the amount of a single factor of production is incrementally increased, holding all other factors of production equal ('' ceter ...
for what they knew as their method of survival.
The philosopher
Oswald Spengler
Oswald Arnold Gottfried Spengler (29 May 1880 – 8 May 1936) was a German polymath whose areas of interest included history, philosophy, mathematics, science, and art, as well as their relation to his organic theory of history. He is best know ...
argued that a civilization in its "winter" would see a disinclination for abstract thinking.
The psychologists David Rand and Jonathan Cohen theorized that people switch between two broad modes of thinking. The first is fast and automatic but rigid, and the second is slow and analytical but more flexible. Rand and Cohen believe that explains why people continue with self-destructive behaviors when logical reasoning would have alerted them of the dangers ahead. People switch from the second to the first mode of thinking after the introduction of an invention that dramatically increases the standards of living. Rand and Cohen pointed to the recent examples of the antibiotic overuse leading to resistant bacteria and failure to save for retirement. Tainter noted that according to behavioral economics, the human decision-making process tends to be more irrational than rational and that as the rate of innovation declines, as measured by the number of inventions relative to the amount of money spent on
research and development
Research and development (R&D or R+D), known in some countries as OKB, experiment and design, is the set of innovative activities undertaken by corporations or governments in developing new services or products. R&D constitutes the first stage ...
, it becomes progressively harder for there to be a technological solution to the problem of societal collapse.
Social and environmental dynamics

What produces modern sedentary life, unlike nomadic
hunter-gatherer
A hunter-gatherer or forager is a human living in a community, or according to an ancestrally derived Lifestyle, lifestyle, in which most or all food is obtained by foraging, that is, by gathering food from local naturally occurring sources, esp ...
s, is extraordinary modern economic productivity. Tainter argues that exceptional productivity is actually more the sign of hidden weakness because of a society's dependence on it and its potential to undermine its own basis for success by not being
self limiting, as demonstrated in Western culture's ideal of perpetual growth.
As a population grows and technology makes it easier to exploit depleting resources, the environment's diminishing returns are hidden from view. Societal
complexity
Complexity characterizes the behavior of a system or model whose components interact in multiple ways and follow local rules, leading to non-linearity, randomness, collective dynamics, hierarchy, and emergence.
The term is generally used to c ...
is then potentially threatened if it develops beyond what is actually sustainable, and a disorderly reorganization were to follow. The scissors model of
Malthusian collapse, in which the population grows without limit but not resources, is the idea of great opposing environmental forces cutting into each other.
The complete breakdown of economic, cultural, and social institutions with ecological relationships is perhaps the most common feature of collapse. In his book ''
Collapse: How Societies Choose to Fail or Succeed'', Jared Diamond proposes five interconnected causes of collapse that may reinforce each other: non-sustainable exploitation of resources, climate changes, diminishing support from friendly societies, hostile neighbors, and inappropriate attitudes for change.
Jared Diamond
Jared Mason Diamond (born September 10, 1937) is an American scientist, historian, and author. In 1985 he received a MacArthur Genius Grant, and he has written hundreds of scientific and popular articles and books. His best known is '' Guns, G ...
, '' Collapse: How Societies Choose to Fail or Succeed'', Penguin Books
Penguin Books Limited is a Germany, German-owned English publishing, publishing house. It was co-founded in 1935 by Allen Lane with his brothers Richard and John, as a line of the publishers the Bodley Head, only becoming a separate company the ...
, 2005 and 2011 ().
Energy return on investment
Energy has played a crucial role throughout human history. Energy is linked to the birth, growth, and decline of each and every society. Energy surplus is required for the division of labor and the growth of cities. Massive energy surplus is needed for widespread wealth and cultural amenities. Economic prospects fluctuate in tandem with a society's access to cheap and abundant energy.
Political scientist
Thomas Homer-Dixon and ecologist
Charles Hall proposed an economic model called
energy return on investment (EROI), which measures the amount of surplus energy a society gets from using energy to obtain energy.
Energy shortages drive up prices and as such provide an incentive to explore and extract previously uneconomical sources, which may still be plentiful, but more energy would be required, and the EROI is then not as high as initially thought.
There would be no surplus if EROI approaches 1:1. Hall showed that the real cutoff is well above that and estimated that 3:1 to sustain the essential overhead energy costs of a modern society. The EROI of the most preferred energy source,
petroleum
Petroleum, also known as crude oil or simply oil, is a naturally occurring, yellowish-black liquid chemical mixture found in geological formations, consisting mainly of hydrocarbons. The term ''petroleum'' refers both to naturally occurring un ...
, has fallen in the past century from 100:1 to the range of 10:1 with clear evidence that the natural depletion curves all are downward decay curves. An EROI of more than ~3 then is what appears necessary to provide the energy for socially important tasks, such as maintaining government, legal and financial institutions, a transportation infrastructure, manufacturing, building construction and maintenance, and the lifestyles of all members of a given society.
The social scientist Luke Kemp indicated that alternative sources of energy, such as solar panels, have a low EROI because they have low energy density, meaning they require a lot of land, and require substantial amounts of rare earth metals to produce.
Hall and colleagues reached the same conclusion. There is no on-site pollution, but the EROI of renewable energy sources may be too low for them to be considered a viable alternative to fossil fuels, which continue to provide the majority of the energy used by humans.
The mathematician Safa Motesharrei and his collaborators showed that the use of non-renewable resources such as fossil fuels allows populations to grow to one order of magnitude larger than they would using renewable resources alone and as such is able to postpone societal collapse. However, when collapse finally comes, it is much more dramatic.
Tainter warned that in the modern world, if the supply of fossil fuels were somehow cut off, shortages of clean water and food would ensue, and millions would die in a few weeks in the worst-case scenario.
Homer-Dixon asserted that a declining EROI was one of the reasons that the Roman Empire declined and fell. The historian Joseph Tainter made the same claim about the Maya Empire.
Models of societal response
According to
Joseph Tainter (1990), too many scholars offer facile explanations of societal collapse by assuming one or more of the following three models in the face of collapse:
# The Dinosaur, a large-scale society in which resources are being depleted at an exponential rate, but nothing is done to rectify the problem because the ruling elite are unwilling or unable to adapt to those resources' reduced availability. In this type of society, rulers tend to oppose any solutions that diverge from their present course of action but favor intensification and commit an increasing number of resources to their present plans, projects, and social institutions.
# The Runaway Train, a society whose continuing function depends on constant growth (''cf.''
Frederick Jackson Turner
Frederick Jackson Turner (November 14, 1861 – March 14, 1932) was an American historian during the early 20th century, based at the University of Wisconsin-Madison until 1910, and then Harvard University. He was known primarily for his front ...
's
Frontier Thesis). This type of society, based almost exclusively on acquisition (such as pillaging or exploitation), cannot be sustained indefinitely. The
Assyrian,
Roman and
Mongol
Mongols are an East Asian ethnic group native to Mongolia, China (Inner Mongolia and other 11 autonomous territories), as well as the republics of Buryatia and Kalmykia in Russia. The Mongols are the principal member of the large family of M ...
Empires, for example, all fractured and collapsed when no new conquests could be achieved.
# The House of Cards, a society that has grown to be so large and include so many complex social institutions that it is inherently unstable and prone to collapse. This type of society has been seen with particular frequency among
Eastern Bloc
The Eastern Bloc, also known as the Communist Bloc (Combloc), the Socialist Bloc, the Workers Bloc, and the Soviet Bloc, was an unofficial coalition of communist states of Central and Eastern Europe, Asia, Africa, and Latin America that were a ...
and other
communist
Communism () is a sociopolitical, philosophical, and economic ideology within the socialist movement, whose goal is the creation of a communist society, a socioeconomic order centered on common ownership of the means of production, di ...
nations, in which all social organizations are arms of the government or ruling party, such that the government must either stifle association wholesale (encouraging dissent and
subversion
Subversion () refers to a process by which the values and principles of a system in place are contradicted or reversed in an attempt to sabotage the established social order and its structures of Power (philosophy), power, authority, tradition, h ...
) or exercise less authority than it asserts (undermining its legitimacy in the public eye).
#:
Tainter's critique
Tainter argues that those models, though superficially useful, cannot severally or jointly account for all instances of societal collapse. Often, they are seen as interconnected occurrences that reinforce one another.
Tainter considers that social complexity is a recent and comparatively-anomalous occurrence, requiring constant support. He asserts that collapse is best understood by grasping four axioms. In his own words (p. 194):
# human societies are problem-solving organizations;
# sociopolitical systems require energy for their maintenance;
# increased complexity carries with it increased costs per capita; and
# investment in sociopolitical complexity as a problem-solving response reaches a point of declining marginal returns.
With those facts in mind, collapse can simply be understood as a loss of the energy needed to maintain social complexity. Collapse is thus the sudden loss of social complexity, stratification, internal and external communication and exchange, and productivity.
Toynbee's theory of decay
In his acclaimed 12-volume work, ''
A Study of History
A, or a, is the first letter and the first vowel letter of the Latin alphabet, used in the modern English alphabet, and others worldwide. Its name in English is '' a'' (pronounced ), plural ''aes''.
It is similar in shape to the Ancient ...
'' (1934–1961), the British historian
Arnold J. Toynbee explored the rise and fall of 28 civilizations and came to the conclusion that civilizations generally collapsed mainly by internal factors, factors of their own making, but external pressures also played a role.
He theorized that all
civilization
A civilization (also spelled civilisation in British English) is any complex society characterized by the development of state (polity), the state, social stratification, urban area, urbanization, and symbolic systems of communication beyon ...
s pass through several distinct stages: genesis, growth, time of troubles, universal state, and disintegration.
For Toynbee, a civilization is born when a "creative minority" successfully responds to the challenges posed by its physical, social, and political environment. However, the fixation on the old methods of the "creative minority" leads it to eventually cease to be creative and degenerate into merely a "
dominant minority
A dominant minority, also called elite dominance, is a minority group that has overwhelming political power, political, economic power, economic, or cultural dominance in a country, despite representing a small fraction of the overall populatio ...
" (that forces the majority to obey without meriting obedience), which fails to recognize new ways of thinking. He argues that creative minorities deteriorate from a worship of their "former self", by which they become prideful, and they fail in adequately addressing the next challenge that they face. Similarly, the German philosopher
Oswald Spengler
Oswald Arnold Gottfried Spengler (29 May 1880 – 8 May 1936) was a German polymath whose areas of interest included history, philosophy, mathematics, science, and art, as well as their relation to his organic theory of history. He is best know ...
discussed the transition from ''Kultur'' to ''Zivilisation'' in his ''
The Decline of the West'' (1918).
Toynbee argues that the ultimate sign a civilization has broken down is when the dominant minority forms a
Universal State, which stifles political creativity. He states:
He argues that as civilizations decay, they form an "Internal Proletariat" and an "External Proletariat". The Internal proletariat is held in subjugation by the dominant minority inside the civilization, and grows bitter; the external proletariat exists outside the civilization in poverty and chaos and grows envious. He argues that as civilizations decay, there is a "schism in the body social", whereby ''abandon'' and ''self-control'' together replace
creativity
Creativity is the ability to form novel and valuable Idea, ideas or works using one's imagination. Products of creativity may be intangible (e.g. an idea, scientific theory, Literature, literary work, musical composition, or joke), or a physica ...
, and ''truancy'' and ''martyrdom'' together replace
discipleship by the creative minority.
He argues that in that environment, people resort to
archaism
In language, an archaism is a word, a sense of a word, or a style of speech or writing that belongs to a historical epoch beyond living memory, but that has survived in a few practical settings or affairs. lexicon, Lexical archaisms are single a ...
(idealization of the past),
futurism
Futurism ( ) was an Art movement, artistic and social movement that originated in Italy, and to a lesser extent in other countries, in the early 20th century. It emphasized dynamism, speed, technology, youth, violence, and objects such as the ...
(idealization of the future),
detachment (removal of oneself from the realities of a decaying world), and
transcendence (meeting the challenges of the decaying civilization with new insight, as a prophet). He argues that those who transcend during a period of social decay give birth to a new Church with new and stronger spiritual insights around which a subsequent civilization may begin to form after the old has died. Toynbee's use of the word 'church' refers to the collective spiritual bond of a common worship, or the same unity found in some kind of
social order
The term social order can be used in two senses: In the first sense, it refers to a particular system of social structures and institutions. Examples are the ancient, the feudal, and the capitalist social order. In the second sense, social orde ...
.
The historian
Carroll Quigley expanded upon that theory in ''The Evolution of Civilizations'' (1961, 1979). He argued that societal disintegration involves the metamorphosis of social instruments, which were set up to meet actual needs, into institutions, which serve their own interest at the expense of social needs. However, in the 1950s, Toynbee's approach to history, his style of civilizational analysis, started to face skepticism from mainstream historians who thought it put an undue emphasis on the divine, which led to his academic reputation declining. For a time, however, Toynbee's ''Study'' remained popular outside academia. Interest revived decades later with the publication of ''
The Clash of Civilizations'' (1997) by the political scientist
Samuel P. Huntington, who viewed human history as broadly the history of civilizations and posited that the world after the end of the Cold War will be multipolar and one of competing major civilizations, which are divided by "fault lines".
Systems science
Developing an integrated theory of societal collapse that takes into account the complexity of human societies remains an open problem.
Researchers currently have very little ability to identify internal structures of large distributed systems like human societies. Genuine structural collapse seems, in many cases, the only plausible explanation supporting the idea that such structures exist. However, until they can be concretely identified, scientific inquiry appears limited to the construction of scientific narratives,
[T.F. Allen, J.A. Tainter et al. 2001 Dragnet Ecology: The Privilege of Science in a Postmodern World. BioScience] using
systems thinking
Systems thinking is a way of making sense of the complexity of the world by looking at it in terms of wholes and relationships rather than by splitting it down into its parts.Anderson, Virginia, & Johnson, Lauren (1997). ''Systems Thinking Ba ...
for careful
storytelling
Storytelling is the social and cultural activity of sharing narrative, stories, sometimes with improvisation, theatre, theatrics or embellishment. Every culture has its own narratives, which are shared as a means of entertainment, education, cul ...
about systemic organization and change.
In the 1990s, the evolutionary anthropologist and quantitative historian
Peter Turchin noticed that the equations used to model the populations of predators and preys can also be used to describe the ontogeny of human societies. He specifically examined how social factors such as
income inequality
In economics, income distribution covers how a country's total GDP is distributed amongst its population. Economic theory and economic policy have long seen income and its distribution as a central concern. Unequal distribution of income causes ...
were related to political instability. He found recurring cycles of unrest in historical societies such as Ancient Egypt, China, and Russia. He specifically identified two cycles, one long and one short. The long one, what he calls the "secular cycle", lasts for approximately two to three centuries. A society starts out fairly equal. Its population grows and the cost of labor drops. A wealthy upper class emerges, and life for the working class deteriorates. As inequality grows, a society becomes more unstable with the lower-class being miserable and the upper-class entangled in infighting. Exacerbating social turbulence eventually leads to collapse. The shorter cycle lasts for about 50 years and consists of two generations, one peaceful and one turbulent. Looking at US history, for example, Turchin identified times of serious sociopolitical instability in 1870, 1920, and 1970. He announced in 2010 that he had predicted that in 2020, the US would witness a period of unrest at least on the same level as 1970 because the first cycle coincides with the turbulent part of the second in around 2020. He also warned that the US was not the only Western nation under strain.
However, Turchin's model can only paint the broader picture and cannot pinpoint how bad things can get and what precisely triggers a collapse. The mathematician Safa Motesharrei also applied predator-prey models to human society, with the upper class and the lower class being the two different types of "predators" and natural resources being the "prey". He found that either extreme inequality or resource depletion facilitates a collapse. However, a collapse is irreversible only if a society experiences both at the same time, as they "fuel each other".
See also
*
Accelerationism
Accelerationism is a range of ideologies that call for the drastic intensification of capitalist growth, technological change, and other processes of social change to destabilize existing systems and create radical social transformations. It is ...
*
Apocalypticism
Apocalypticism is the religious belief that the Eschatology, end of the world is imminent, even within one's own lifetime. This belief is usually accompanied by the idea that civilization will soon come to a tumultuous end due to some sort of ...
*
Decadence
*
Doomer
*
Doomsday cult
*
Historic recurrence
Historic recurrence is the repetition of similar events in history. The concept of historic recurrence has variously been applied to overall human history (''e.g.'', to the rises and falls of empires), to repetitive patterns in the history of ...
*
Human extinction
*
John B. Calhoun's mouse experiments
*
Lost city In the popular imagination, a lost city is a real, once-prosperous and well-populated area of human habitation that fell into terminal decline and whose location was later forgotten.
Lost City, The Lost City, or Lost Cities may also refer to:
Pl ...
*
Millenarianism
Millenarianism or millenarism () is the belief by a religious, social, or political group or movement in a coming fundamental transformation of society, after which "all things will be changed". Millenarianism exists in various cultures and re ...
*
Ruins
*
Subnature
*
Survivalism
Survivalism is a social movement of individuals or groups (called survivalists, doomsday preppers or preppers) who proactively prepare for emergencies, such as natural disasters, and other disasters causing disruption to social order (that is, ...
*
Social alienation
Social alienation is a person's feeling of disconnection from a group whether friends, family, or wider society with which the individual has an affiliation. Such alienation has been described as "a condition in social relationships reflected b ...
*
Weltschmerz
;Malthusian and environmental collapse themes
*
Collapsology
*
Behavioral sink – rat colony collapse
*
Catastrophism
In geology, catastrophism is the theory that the Earth has largely been shaped by sudden, short-lived, violent events, possibly worldwide in scope.
This contrasts with uniformitarianism (sometimes called gradualism), according to which slow inc ...
* ''
Earth 2100''
*
Ecological collapse
An ecosystem, short for ecological systems theory, system, is defined as a collection of interacting Organism, organisms within a biophysical environment. Ecosystems are never static, and are continually subject to both stabilizing and destabiliz ...
*
Global catastrophic risk
A global catastrophic risk or a doomsday scenario is a hypothetical event that could damage human well-being on a global scale, endangering or even destroying modern civilization. Existential risk is a related term limited to events that co ...
*
Human overpopulation
Human overpopulation (or human population overshoot) is the idea that human populations may become too large to be sustainability, sustained by their environment or resources in the long term. The topic is usually discussed in the context of wor ...
*
Medieval demography
Medieval demography is the study of human demography in Europe and the Mediterranean during the Middle Ages. It estimates and seeks to explain the number of people who were alive during the Medieval period, population trends, life expectancy, fa ...
*
Millennium Ecosystem Assessment
The Millennium Ecosystem Assessment (MA) is a major assessment of the human impact on the environment, called for by the United Nations Secretary-General Kofi Annan in 2000, launched in 2001 and published in 2005 with more than $14 million of ...
*
Overshoot
;Cultural and institutional collapse themes
*
Civil war
A civil war is a war between organized groups within the same Sovereign state, state (or country). The aim of one side may be to take control of the country or a region, to achieve independence for a region, or to change government policies.J ...
*
Degrowth
Degrowth is an Academic research, academic and social Social movement, movement critical of the concept of economic growth, growth in Real gross domestic product, gross domestic product as a measure of Human development (economics), human and econ ...
*
Economic collapse
Economic collapse, also called economic meltdown, is any of a broad range of poor economic conditions, ranging from a severe, prolonged depression with high bankruptcy rates and high unemployment (such as the Great Depression of the 1930s), t ...
*
Failed state
A failed state is a state that has lost its ability to fulfill fundamental security and development functions, lacking effective control over its territory and borders. Common characteristics of a failed state include a government incapable of ...
*
Fragile state
A fragile state or weak state is a country characterized by weak state capacity or weak state legitimacy leaving citizens vulnerable to a range of shocks. The World Bank, for example, deems a country to be ‘fragile’ if it (a) is eligible for a ...
*
Group cohesiveness
Group cohesiveness, also called group cohesion, social harmony or social cohesion, is the degree or strength of bonds linking members of a social group to one another and to the group as a whole. Although cohesion is a multi-faceted process, it ...
*
Language death
In linguistics, language death occurs when a language loses its last native speaker. By extension, language extinction is when the language is no longer known, including by second-language speakers, when it becomes known as an extinct langua ...
*
Progress trap
*
Social cycle theory
Social cycle theories are among the earliest social theories in sociology. Unlike the theory of social evolutionism, which views the evolution of society and human history as progressing in some new, unique direction(s), sociological cycle th ...
*
Sociocultural evolution
Sociocultural evolution, sociocultural evolutionism or social evolution are theories of sociobiology and cultural evolution that describe how Society, societies and culture change over time. Whereas sociocultural development traces processes t ...
*
State collapse
State collapse is a sudden dissolution of a sovereign state. It is often used to describe extreme situations in which state institutions dissolve rapidly.
When a new regime moves in, often led by the military, civil society typically fails to ...
*
Urban decay
Urban decay (also known as urban rot, urban death or urban blight) is the sociological process by which a previously functioning city, or part of a city, falls into disrepair and decrepitude. There is no single process that leads to urban decay. ...
;Systems science
*
Failure mode and effects analysis
Failure is the social concept of not meeting a desirable or intended Goal, objective, and is usually viewed as the opposite of success. The criteria for failure depends on context, and may be relative to a particular observer or belief system ...
*
Fault tree analysis
*
Hazard analysis
A hazard analysis is one of many methods that may be used to assess risk. At its core, the process entails describing a system object (such as a person or machine) that intends to conduct some activity. During the performance of that activity, a ...
*
Risk assessment
Risk assessment is a process for identifying hazards, potential (future) events which may negatively impact on individuals, assets, and/or the environment because of those hazards, their likelihood and consequences, and actions which can mitigate ...
*
Systems engineering
Systems engineering is an interdisciplinary field of engineering and engineering management that focuses on how to design, integrate, and manage complex systems over their Enterprise life cycle, life cycles. At its core, systems engineering uti ...
Notes
References
Bibliography
*
Further reading
*
 
Comment
by Prof. Michael Kelly, disagreeing with the paper by Ehrlich and Ehrlich; an
response
by the authors
*
Homer-Dixon, Thomas. (2006).
The Upside of Down: Catastrophe, Creativity, and the Renewal of Civilization. Washington DC: Island Press.
* Huesemann, Michael H., and Joyce A. Huesemann (2011)
''Technofix: Why Technology Won’t Save Us or the Environment'' Chapter 6, "Sustainability or Collapse", New Society Publishers, Gabriola Island, British Columbia, Canada, , 464 pp.
*
*
Wright, Ronald. (2004).
A Short History of Progress. New York: Carroll & Graf Publishers. .
External links
{{DEFAULTSORT:Societal Collapse
Doomsday scenarios
Economic problems
Social systems
Theories of history
Dark ages