Contemplating the crash

June 30, 2026

Peter Sainsbury is perfectly correct in stating that a smaller human population will not reduce climate change, at least in the short term. However in presenting the main scenarios for population, he overlooks the one that is most likely – and which nobody wants to talk about: catastrophic population crash.

This will occur as global food systems collapse under climate and resource pressures, famine being followed by the other Apocalyptic Horsemen of war and disease. And it can occur within a single generation even, according to some, before 2050. This is a perfectly natural process, which happens to every animal that overbreeds and outruns its resources. Once it begins, people may be more open to actions designed to limit human impact on the planet.

Recent science states the carrying capacity the Earth is around 2-2.5 billion humans. Anything beyond that increases the probability of a crash. If the crash entails carbonising most of the human (10bn) and livestock (36bn) populations, the return of forests, wilderness and the ocean sink, then relative climate stability may return faster than expected. But not the Holocene conditions that gave rise to modern humanity. For that we need the next Ice Age.