On: IPCC Scientist's Nobel Moment: No developing catastrophe nor human activity cause

The economic argument from the AGW advocates (Stern report) is that we should spend $100 today to avoid spending $95 (or less) in the future.

Why or how is it going to get cheaper to deal with if we procrastinate?

The "cures" are frightfully expensive. The mitigations and costs are less so. (The "cures" do get less expensive as technology develops, but Stern didn't include that factor.)

Read the Stern report. Notice the discount rate. (Stern does argue that it's appropriate to spend $100 now to avoid spending $95 in the future.)

Or, maybe you want to argue that Stern is wrong about the economics.

I think that he is, but not in a way that strengthens his conclusion that we should apply the cures now. (Yup - he's an AGW advocate and a commonly cited source for the economic argument.)