One common issue with “existential risk” is that it’s so easy to conflate it with “extinction risk”. It seems that even you end up falling into this use of language. You say: “if there were 20 percentage points of near-term existential risk (so an 80 percent chance of survival)”. But human extinction is not necessary for something to be an existential risk, so 20 percentage points of near-term existential risk doesn’t entail an 80 percent chance of survival.
In this case I meant ‘an 80 percent chance of surviving the threat with our potential intact’, or of ‘our potential surviving the threat’.
While this framework is slightly cleaner with extinction risk instead of existential risk (i.e. the curve may simply stop), it can also work with existential risk as while the curve continues after some existential catastrophes, it usually only sweeps out an a small area. This does raise a bigger issue if the existential catastrophe is that we end up with a vastly negative future, as then the curve may continue in very important ways after that point. (There are related challenges pointed out by another commenter where out impacts on the intrinsic value of other animals may also continue after our extinction.) These are genuine challenges (or limitations) for the current model. One definitely can overcome them, but the question would be the best way to do so while maintaining analytic tractability.
In this case I meant ‘an 80 percent chance of surviving the threat with our potential intact’, or of ‘our potential surviving the threat’.
While this framework is slightly cleaner with extinction risk instead of existential risk (i.e. the curve may simply stop), it can also work with existential risk as while the curve continues after some existential catastrophes, it usually only sweeps out an a small area. This does raise a bigger issue if the existential catastrophe is that we end up with a vastly negative future, as then the curve may continue in very important ways after that point. (There are related challenges pointed out by another commenter where out impacts on the intrinsic value of other animals may also continue after our extinction.) These are genuine challenges (or limitations) for the current model. One definitely can overcome them, but the question would be the best way to do so while maintaining analytic tractability.