World Economic Forum article presents four civilizations destroyed entirely or in part by climate change: Akkadia, Maya, Greenland Norse and Khmer
Jared Diamond, in his book Collapse: How Societies Choose to Fail or Succeed, contributes additional examples of civilizations overcome by disaster, in almost all cases by population exceeding the capacity of the land to support this population.
Greenland (Norse)
Easter Island
Polynesians of Pitcairn Island
Anasazi of Southwestern North America
Maya
Overpopulation can be defined as the condition of having a population so dense as to cause environmental deterioration, an impaired quality of life, or a population crash (Merriam-Webster).
The ability of a particular environment to support a specific population of biological lifeforms is called its carrying capacity. Ideally, carrying capacity should comfortably exceed total population, as fluctuations in climate can impact carrying capacity.
It is well-established that climate changes constantly, in a variety of long-term cyclical patterns. Climate-based fluctuations and resulting changes to carrying capacity are exacerbated by human activities and population increase.
Traditional evolutionary solutions to overpopulation have been broken due to life-extending technologies, increases the pressure on carrying capacity, as an increasing population must still rely on the same global resource base.
Carrying Capacity vs Population density
Niche Construction changes to ecosystem based on a species altering the environment of that ecosystem.
---ARGUMENT---
Agricultural Technology increases the carrying capacity.
Increasing population places stress on carrying capacity
Collapse occurs when population exceeds carrying capacity.
Carrying capacity can change based on a variety of local conditions, one of which is climate (desertification, long term cycles, etc)
The closer the population to the maximum carrying capacity, the more vulnerable the food system becomes to changes in overall conditions