This price rise creates an incentive for people to discover more of the resource, ration and recycle it, and eventually, develop substitutes.

This suggests, Simon claims, an enduring trend of increased availability that will not cease in the foreseeable future, despite continued population growth.

Simon argues that for thousands of years, people have always worried about the end of civilization brought on by a crisis of resources.

Ehrlich was the author of a popular book, The Population Bomb, which argued that mankind was facing a demographic catastrophe with the rate of population growth quickly outstripping growth in the supply of food and resources.

A large section of the book is dedicated to showing how population growth ultimately creates more resources.

The basic argument echoes the overarching thesis: as resources become more scarce, the price rises, creating an incentive to adapt.