How to Distinguish Environmental Doomsaying from Rational Attention to Potential Envrionmental Catastrophes

It's easy: If the concern is presented with full acknowledgement of risks (probabilities of occurrence) and uncertainties, it is not doomsaying but rational attention to potential environmental catastrophes. Doomsayers never talk about the relative (im)probabilities of the crises and catastrophes they foretell. With respect to climate change, for example, Al Gore (see, e.g., here) is a doomsayer; Martin Weitzman (see here) and Richard Posner (see here) are rational economists (which is not to say that they would necessarily agree about how much and how soon greenhouse gas emissions should be mitigated).