It’s sad when loved ones die, and few of us look forward to our own demise; hence the perennial quest for an elixir of eternal life, or at least a cu… - Richard Heinberg

For a population of field mice in overshoot, the critical resource might consist of small plants whose unusually robust growth has been triggered by high levels of rainfall. For humanity currently, the critical resource is fossil energy. Temporary energy abundance has led to many good things (for some of us, anyway): more food, more people, more commercial products, more knowledge, more comfort, and more convenience. But we are about to become victims of our own success.

Global human population has doubled three times in the past 200 years, surging from 1 billion in 1820 to 2 billion in 1927, to 4 billion in 1974, to 8 billion today. Its highest rate of growth was in the 1960s, at over 2 percent per year; that rate is now down to 1.1 percent. If growth continues at the current rate, we’ll have about 18 billion people on Earth by the end of this century. All of this would be fine if we lived on a planet that was itself expanding, doubling its available quantities of minerals, forests, fisheries, and soil every quarter-century, and doubling its ability to absorb industrial wastes. But we don’t. It is essentially the same beautiful but finite planet that was spinning through space long before the origin of humans.

Climate change is a wicked problem… [and] there is no way to solve it without sacrificing something that society currently holds dear, and without thereby generating more problems. For example, shrinking the economy would reduce carbon emissions, but it would throw a lot of people out of work (in effect, we did trial runs during the financial crash of 2008 and the COVID pandemic of 2020; both times, carbon emissions plunged, yet everyone was eager to “get back to normal”). Building vast amounts of low-carbon energy-producing and energy-using infrastructure would also reduce emissions, but that would require tens of trillions of dollars of investment as well as enormous quantities of depleting, non-renewable minerals—the mining of which would generate pollution and destroy wildlife habitat.