Exactly. If global warming said the typical outside temperature in Seattle doubles to almost 600K then it'd be fair to argue that's crazy people extrapolating - water isn't even liquid at that temperature, no model we have could make sense. But actually the model says it will go up say 2 or 3K. Much less like a wild extrapolation, and unfortunately still completely terrifying because that is already far too much.

How does anyone know what temperature rise is or isn't compatible with civilization as we know it, within the range of predicted temperature rises? One of the problems is that civilization is dynamic. New technologies come along, people change their habits, etc.