Diamond lists five major causes that can lead to societal collapse: environmental degradation, climate changes, hostile neighbors, friendly trading neighbors who pull away, and inability to adjust to massive change.

A typical scenario involves a people who cut down their forests, replace them with farms, enjoy a boom in food production and a growth in population, then suffer from soil depletion, alternating floods and droughts, loss of trade, and attacks from outsiders. Despite these dangers, the society continues its wasteful ways, refusing to alter time-honored traditions. Famine and collapse quickly follow, and the civilization all but disappears.

The author also lists 12 types of environmental abuse that can put societies at risk. Eight of these affect all societies, old and new: deforestation, soil problems, water problems, overhunting, overfishing, alien species, overpopulation, and increased per-capita impact of a people on the environment. Four problems also apply to modern societies: human-caused climate change, build-up of toxins, energy shortages, and loss of full photosynthetic capacity.

Deforestation recurs as the single most important type of environmental abuse. The wholesale felling of a region’s trees—for firewood and wood products, and to make room for farms—at first generates a wealth of food and resources.