i think the ipd is the wrong game model for global warming. i don't think it represents either the tragedy of the commons or the free rider effect (depending on which you think global warming plus attempts to reduce it is) very well.

more seriously, in my opinion, is the valuation of time. If I don't give a hoot for future generations, and *my* time is highly valued, I am

a: not going to waste my time iterating a game that practically can stretch decades
b: going to gladly pay you tuesday for carbon dioxide today.

I'm thinking the whole thing is buzzword sales- IPD is easily understood and sellable. But, I think the most egregious misapplication is that of presumed guilt: in the PD, the assumption is that both parties are actually guilty of the crime, and believe it to be so. In reality (and in the environment) nations may not feel that they are guilty of any crime, and therefore are not necessarily going to respond logically (willing to do the crime=willing to do the time) to punishment.

yup, the discounting of time is one of the things i was thinking of. the ipd assumes a transaction today has the same payoffs as a transaction tomorrow, and no formalism for anything else -- especially, as you note, borrowing from tomorrow for gain today.

i'm a bit more willing to assume stupidity rather than malice when people use the ipd for too many problems: i think it's the only hammer they've heard of. some years ago, i went to a seminar on game theory and international relations. one speaker described (in fair detail) that given what was known at the time, the us decision to blow off kyoto was in fact the right answer. interestingly, not only was it the best choice for the us, it wasn't a bad choice overall.

the short form of that analysis goes like this, iirc: meeting the rather arbitrary kyoto targets would have been very expensive for the us, where at the time, industry was relatively efficient and running at capacity, but cheap for the europeans, where western european industry was relatively inefficient and due to a recession at the time, had excess capacity. so, to maximize carbon reduction while minimizing cost, the euros should just turn off all their old powerplants¹ and factories. but this raises questions of "fairness", which game theory can't (by itself) answer.

1: except the french and the nordics, who get most of their power from nukes and water.

When the principal author's only credentials are "venture capitalist", it may be horribly biased on my part but I automatically assume malice. "Not that there's anything wrong with being a capitalist", but I don't think they get rich quick from being stupid.