The authors of the cited paper claim that conditional on nuclear winter, the risk of human population going to zero from the direct climate effects is very low, noting that human ancestors survived supervolcanoes and past ice ages. This could interact with other things though (Industrial Revolution was a fluke, synthetic bio organisms finish us off, asteroids hit while civilization is down, etc), and there is model uncertainty regarding the nuclear winter magnitude and distribution.
The authors of the cited paper claim that conditional on nuclear winter, the risk of human population going to zero from the direct climate effects is very low, noting that human ancestors survived supervolcanoes and past ice ages. This could interact with other things though (Industrial Revolution was a fluke, synthetic bio organisms finish us off, asteroids hit while civilization is down, etc), and there is model uncertainty regarding the nuclear winter magnitude and distribution.