Climate Policy

[Jester]

Finally, a model is often judged to be 'good' or 'bad' on the basis of what it predicts. But since there often isn't anything objective to compare it to, then it boils down to the subjective. The modeler often has a general idea of what he expects. If the model more or less gives him that, then it is good, otherwise it isn't. It appears that none of the climate models presently in existence can fully reproduce the *known* history of the planet. Why then believe them for the future?

Does hindcasting perform so poorly? My understanding, again self-admittedly inexpert, is that current models actually do quite well at predicting past temperature. Asking a single model to predict the entire global climate past is probably not possible or realistic, but doing things like predicting 20th century temperatures seems to yield solid results.

Is this based on your understanding from the late 1980s, plus having not heard of developments since? Or have you actually looked at the hindcasting skill of more current models? I'm afraid I'd be totally lost doing so, but my impression was obviously more positive than yours.

-Jester