Societal collapse
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, and misfortune.
[11] 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.
[15] 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.
[28] 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.
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.
[31] 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.
[35] Around 3,000 BC, people of the pastoralist Yamnaya culture from the Pontic–Caspian steppe, 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 by most contemporary linguists, archaeologists, and geneticists.
[36] A mysterious loose confederation of fierce maritime marauders known as the Sea Peoples was identified as one of the main causes of the Late Bronze Age Collapse in the Eastern Mediterranean.
[note 2][39][better source needed] A combination of internal strife, economic weakness, and relentless invasions by the Germanic peoples pushed the Western Roman Empire into terminal decline.
[43][better source needed] 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.
[46] The last remaining principality of Champa, Panduranga (modern-day Phan Rang, Vietnam), survived until 1832,[48] when Emperor Minh Mạng (Nguyễn Phúc Đảm) conquered it after centuries of Cham–Vietnamese wars.
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.
"[58] From the description of symptoms by the Greek physician Galen, 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 or measles.
According to the Byzantine historian Procopius of Caesarea, 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, 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.
Caliph Abu Bakr 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.
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.
[78] 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.
[79] 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.
[81] 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.
[38] The anthropologist Joseph Tainter theorized that collapsed societies essentially exhausted their own designs and were unable to adapt to natural diminishing returns for what they knew as their method of survival.
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, it becomes progressively harder for there to be a technological solution to the problem of societal collapse.
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.
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.
[5][87] 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.
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.
[91] 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.
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.
