This Sustainable Life


294: Population: How Much Is Too Much?

Ep. 294

What is Earth's carrying capacity? Why is it important?

Many ask how we will feed 10 billion people. Mathematician way of asking is if we can feed so many and if so how. Maybe we can't.

First, don't want to know. While it depends on many assumptions that aren't hard or measurable numbers, like standard of living, distribution of resources, and technology, we can say it's maximum misery per person.

How do we narrow it down? Could ask resources per person and how much resources Earth can provide. Limits to Growth projects how much planet would sustain from a systems perspective including history and how we live our values.

I prefer a historical perspective I learned from Alan Weisman based on the Haber-Bosch process, which enabled artificial fertilizer. Before artificial fertilizer, limitations on fixing nitrogen to grow food suggest Earth could sustain about 2 billion, enough to create Einstein and Mozart. Want people like Jesus, Buddha, Laozi, and Aristotle? We needed only a few hundred million to create them.

If we're over the planet's carrying capacity, especially by factor of 3 or 4, strategy isn't to ask how to feed 10 billion but if we can lower the population before processes like famine, disease, loss of critical resources, war, and so on do it for us.

I couldn't answer except in ways where the cure was worse than the disease, but the history of Thailand's Mechai Viravaidya's leading a nation-scale cultural shift from 7 babies per woman to 1.5, voluntarily, peacefully, leading to abundance, prosperity, and stability changed everything for me.

Mechai's success makes lowering the population plausible and fun. The limitations of growing food without artificial fertilizer make it necessary to avoid famine and other natural disasters. These two factors clarify our priority, it seems to me.

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