AAP 2026 CONFERENCE

I have argued that uncertainty assessment of climate model predictions should typically be of the extent to which they are epistemically possible and that, in some cases where they are epistemically possible, the possibilities should further be ranked as to how remote they are. I have also argued that, in the climate science context, an epistemic possibility should be taken to be a possibility that is not recognised to be excluded by what is known and is compatible with knowledge that approximates the basic way things are in the domain the possibility is about. In the present paper, I explain my position on assessing uncertainty in climate science and consider and respond to two challenges to its application, specifically, those of how to operationalise my notion of epistemic possibility and how to classify possibilities that fall short of being epistemically possible. I illustrate my view and responses in the case of the assessment of the possibility of marine ice-cliff instability induced sea-level rise.