"If H[omo] sapiens does not go extinct, the human population will decline drastically as we will be forced to return to making a living as hunter‐gatherers or simple horticulturalists. Also, the earth after the collapse of human civilization will be a very different place than the biosphere that supported the rise of civilization. There will be a long-lasting legacy of altered climate, landscapes, and biogeochemical cycles, depleted and dispersed stocks of fossil fuels, metals, and nuclear ores, and diminished biodiversity. The most powerful species in the 3.5-billion-year history of life has transformed the earth and left a mark that will endure long after its passing."