That's an interesting point. How precise do you think we have to be with respect to feedbacks in the climate system if we are interested in an existential risk question? And do you have other uncertainties in mind or just uncertainties about feedbacks?

The first thing I thought on reading your reply was that insofar as the evidence supports positive feedbacks, the evidence also supports the claim that there is existential risk from climate change. But then I thought maybe we need to know more about how far away the next equilibrium is -- assuming there is one. If we are in or might reach a region where temperature feedback is net positive and we run away to a new equilibrium, how far away will the equilibrium be? Is that the sort of uncertainty you had in mind?