Civilizational collapse is the systemic breakdown or retreat of a complex society resulting in a major decline or destruction of its social and economic structures, political organization, and culture. It is a phenomenon typically driven by environmental or economic degradation, resource depletion, war and conquest, and social disruption that can occur over generations or span centuries, but can also occur suddenly or over a short period of time. Civilizational collapse has historically entailed significant social disruption, population decline and a fracturing of the culture, leading to a lack of cohesion, identity, and infrastructure. Ultimately, it is the result of unsustainable social and economic practices and unsustainable resource exploitation, combined with a failure by the society to respond adequately to changes in its external and internal conditions.

See also: catastrophic risk, climate change, collective action, existential risk, mutually assured destruction