I mean literal extinction in the long-term. The current mass extinction we are in most closely resembles the Permian-Triassic extinction which was caused by a runaway greenhouse effect acidifying the oceans and warming the atmosphere: https://en.wikipedia.org/wiki/Permian–Triassic_extinction_ev.... It wiped out 96% of known species at the time: https://phys.org/news/2018-09-end-permian-extinction-earth-s...