They further add that both the economic and population growth must be exponential, but they don’t consider the results of exponential growth.
Exponentials grow fast. In less than the time from the Roman Empire until now–that is, within a few thousand years–even modest exponential growth would run into physical absurdities, as illustrated in these posts in the Do The Math blog, by Caltech-trained UC San Diego physics professor Tom Murphy:
(My PhD is in physics, so I understand Tom’s approach. I hope readers don’t misunderstand how a physicist describes things like energy, growth, and exponentials. It requires understanding conservation of energy and thermodynamics, in this case.)
If we had infinite resources, infinite growth would work. We don’t, though, so trying to grow forever will result in unintended consequences.
Some economists have studied steady-state economies, which differ from stagnant economies. Culture and societies would differ from today’s growth-based economies, but aren’t impossible.
Among the economists that imagined steady-state economies is Adam Smith, pictured above on the twenty pound note.
Societies have lived for long times in steady states. Think of islands that could support tens of thousands of people, where people knew much of the rest of the population.
They knew that if a couple had three children, another couple had to have fewer. They could see that resources would run out otherwise.
Maybe because of the Earth’s size relative to a person or because of the distribution of resources, we seem unable to see the limits of resources like an island nation can. The Earth’s…