Two Kinds of Societal Collapse

Running the model in dierent scenarios produces two kinds of collapses, either due to scarcity of labor (following an inequality-induced famine) or due to scarcity of Nature (depletion of natural resources). We categorize the former case as a Type-L (Disappearance of Labor) Collapse and the latter as a Type-N collapse (Exhaustion of Nature). In a Type-L collapse, growth of the Elite Population strains availability of resources for the Commoners. This causes decline of the Commoner Population ...

 The HANDY Model is Based On Predator-Prey Cycles

As indicated above, Human And Nature DYnamics (HANDY) was originally built based on the predator-prey model. We can think of the human population as the predator", while nature (the natural resources of the surrounding environment) can be taken as the prey", depleted by humans. In animal models, carrying capacity is an upper ceiling on long-term population. When the population surpasses the carrying capacity, mechanisms such as starvation or migration bring the population back down. However, ...