If a full scale thermonuclear war were to occur, would it cause the literal extinction of the human species, as well as life on Earth as a whole? I've read about military supercomputer simulations of this scenario, and does not result in human extinction. Although many Billion people do die. Probably about half or 3/4 of the entire world's population. But not into extinction. Even with the nuclear stockpiles during the peak of the cold war. Some other things I have read do suggest that such an event would result in total extinction. Especially if chemical and biological weapons are used. In the distant past, microbial life on Earth beneath the ocean floors has survived impacts by giant meteors, while all other life was annihilated. Within a few Million years, life on Earth was back and thriving.