Current Estimates for Likelihood of X-Risk?

In talk­ing with peo­ple about the long-term fu­ture, I’ve found it to be ex­tremely helpful to give an es­ti­mate for the per­cent chance hu­man­ity goes ex­tinct by 2100 (or in 100 years). Right now, I say ~10% or 5-19%, and then say some­thing like “it would be re­ally nice if we could get that num­ber be­low 1%”. My es­ti­mate is taken from these sources:

  • FHI’s ca­sual 2008 sur­vey of var­i­ous x-risks. Taken to­gether, they give a 19% chance by 2100.

  • The 2007 Stern Re­view, a 700-page re­port on cli­mate change. It uses 0.1% as an up­per bound mod­el­ing as­sump­tion for an­nual ex­tinc­tion risk, which means 9.5% in the next 100 years (by 2107).

  • This July 2018 Vox ar­ti­cle from Liv Bo­eree that refer­ences the FHI study and also says “5 to 19 per­cent chance of com­plete hu­man ex­tinc­tion by the end of this cen­tury”. (I’m not sure where the 5% comes from?)

  • This 2016 re­port on GCRs from FHI and the Global Pri­ori­ties Pro­ject. They refer­ence the two sources above and just say it’s hard to cre­ate a rea­son­able es­ti­mate.

How­ever, I find the strength of these es­ti­mates pretty weak. If some­one were to ask me to “back up” my 10% num­ber, the best I’d have is an in­for­mal sur­vey cir­cu­lated at an x-risk con­fer­ence in 2008. So, a cou­ple ques­tions:

  1. Are there other sources that I’m miss­ing?

  2. Do oth­ers also feel like it would be helpful to have an up­dated/​more rigor­ous es­ti­mate here? (Or is it not ac­tu­ally helpful to op­er­ate at this level of ab­strac­tion? i.e. Should we con­cen­trate just on in­di­vi­d­ual sources of x-risk in­stead?)

  3. Is it even pos­si­ble to cre­ate an es­ti­mate like this? Or is the range of un­cer­tainty just too large, that we’d need to give an es­ti­mate like 2-59%? (Clearly, this gets more difficult the longer we try to pro­ject out. But can’t we es­ti­mate it for 2050, 2075, or 2100?)

Thanks for your thoughts and help!