A roadmap of past collapses

Although there is no conclusive explanation of why civilizations collapse, there are factors that can contribute.

• Climatic change can result in disaster, resulting in crop failure, starvation, and desertification. The Akkadians, the Mayan, the Roman Empire, and many others coincided with abrupt climatic changes.
• Ecological collapse theory: When societies overdo the carrying capacity of their environment, e.g., excessive deforestation, water pollution, soil degradation, and the loss of biodiversity.
• Inequality and oligarchy: As a population increases, the supply of labor outstrips demand, workers become cheap and society top-heavy. Political violence follows.
• Complexity: Accumulated complexity and bureaucracy eventually leads to collapse. The returns from complexity eventually reach a point of diminishing returns, causing collapse.
• External shocks: War, natural disasters, famine, and plagues. The Aztec Empire was brought to its knees by Spanish invaders. Early agrarian states were passing due to deadly epidemics.
• Randomness: Collapse is often random and independent of age.