Perpetual growth is indeed delusional

October 1, 2025

Julian Cribb is right to assert that the idea of perpetual growth on a finite planet is delusional. His estimate of a maximum sustainable global population of about two billion is also about right, though even that may be too high should climate change render much of the planet uninhabitable.

Maps of the world at three degrees warming, that show regions that have become uninhabitable, are profoundly alarming. They include all of India and Pakistan, for example. And what if the Atlantic Meridional Overturning Circulation shuts off? It means the end of agriculture in much of Britain and Ireland and many countries in Western Europe.

James Lovelock, co-proposer of the Gaia Hypothesis, once predicted that by the end of the century, “climate change will reduce the human population to a few breeding pairs surviving near the Arctic”. This implies a mass die-off of people that does not bear contemplation, and probably the loss of civilisation as well.

However, we’re not called “sapiens” for nothing, and hopefully our inherent wisdom will win the day. That means pulling out all stops to mitigate climate change. It means net zero emissions by 2035 and rapidly drawing down carbon out of the atmosphere.