On the other hand twenty years is not long enough to significantly separate most of the scenarios including those with various ameloriations and in any case there appears to be a decades long induction period related to the oceans acting as heat sinks. Thus a 20 year bet is more or less a bet on climate sensitivity and Prof. Pielke’s point, though well taken on a hundred year long scale, probably makes little difference.

To me the two big uncertainties that could effect a 20 year bet are a large volcanic eruption or a huge methane burp from the clathrates.

I just realized that I made a serious mistake in that last comment. My comment implies (well, states) that there were no penalties for lying, and no rewards for telling the truth, and the IPCC TAR projections writers lied.

But I did NOT mean that, absent any signals at all, the IPCC TAR projection writers lied. They actually had a very, very large *reward* for lying, in the form of vastly more research money.

That’s why they lied. It doesn’t excuse what they did, but it explains that they didn’t just lie for the fun of it.

I just posted this comment on “Real Climate.” I’m not sure when, if ever, they will publish it. (They don’t like words like, “lying”…at least not when applied to the authors of the IPCC TAR.) Anyway, I thought you might be interested.

Best wishes,
Mark

Roger Pielke writes, “One interesting point relevant to policy about bets focused on global average temperature (GAT) — it appears from this discussion that there is unanimous agreement among those who disagree on what future GAT will be that there is no need to discount for policy interventions. That is, the IPCC projections are not conditioned upon assumptions about policies being implemented related to emissions. A functioning market would make this more apparent (e.g., if the market price is equal to the IPCC midpoint scenario),…”

I don’t think the market price will equal the IPCC Third Assessment Report (TAR) midpoint scenario, unless the market was seriously ignorant. The IPCC midpoint scenario is completely bogus. And the IPCC TAR midpoint scenario becomes INCREASINGLY bogus the further one goes out in time. The explanation for why the IPCC midpoint scenario is bogus, and becomes INCREASINGLY bogus the further one goes out in time is a simple matter of economics:

1) There were no penalties to the people who made the IPCC TAR projections for lying, and

2) There were no rewards to the people who made the IPCC TAR projections for telling the truth.

No penalties for lying, and no rewards for telling the truth. So the people who made the IPCC TAR projections performed the economically rational act: they lied. (Note: Robert Watson was later dismissed from heading the IPCC, so possibly there was one person who was penalized for the fraudulent projections.)

Some evidence for that fact that the IPCC TAR projections writers lied can be seen simply by looking at the results of the Second IPCC Assessment Report (SAR), versus the TAR. The SAR projected a warming from 1990 to 2100 of 0.9 to 3.5 degrees Celsius. The TAR projected a warming for the same period of 1.4 to 5.8 degrees Celsius.

But stronger evidence that the IPCC TAR projections writers lied can be seen from the fact that some of the highest projections were added AFTER PEER REVIEW (apparently at the urging of Robert Watson):

http://www.sepp.org/NewSEPP/IPCC-Ex_PoliticalScientist.htm

On the charitable website known as “Long Bets,” I have placed my OWN “midpoint” values for 2030, 2070, and 2100, versus the midpoints in the IPCC TAR. I have challenged any IPCC TAR author to bet that their projections are better than mine:

http://www.longbets.org/181

Further, on my own weblog, I have offered James Annan and William Connolley $4, up to a maximum of $200, for every IPCC TAR author they get to come on the Long Bets website, and “vote” on my projections versus the IPCC’s. (I will pay them $4 for every vote, regardless of whether it’s a vote for my side of the bet or against my side of the bet.) Finally, also on my weblog, I have challenged them to make me the same offer ($4 for every IPCC TAR author vote, up to a maximum of $200, regardless of the side on which the vote is cast.)

http://markbahner.typepad.com/random_thoughts/2005/06/free_money_offe.html

One interesting point relevant to policy about bets focused on global average temperature (GAT) — it appears from this discussion that there is unanimous agreement among those who disagree on what future GAT will be that there is no need to discount for policy interventions. That is, the IPCC projections are not conditioned upon assumptions about policies being implemented related to emissions. A functioning market would make this more apparent (e.g., if the market price is equal to the IPCC midpoint scenario), of course, but it appears to me that in the debate motivated by James so far that there is no expectation that emissions reductions policies will have a discernable effect on the climate (as measured by GAT) by 2030 (the terminal point of the bet). From a policy perspective, this suggests a number of possibilities, among them, (a) that the benefits of emissions reduction (as related to GAT) lie beyond 2030, (b) that everyone implicitly agrees that emissions reductions are unlikely (I doubt this is the case), (c) that emissions reductions of any conceivable amount will have no noticable effect on GAT, and so on. If bettors expect that emissions reductions will have a discernable influence on GAT over this period, then it should be apparent in the market value for GAT, which would be less than the IPCC’s non-policy mid-point projection.

Thanks for your comment. I use the phrase “schoolyard brawl” to refer to bets with names attached to them. The value of a prediction market lies in the market. Efficient market theory holds that it is the integration of many perspectives that provides the best available take on uncertain information (hence, efficient). I’ll grant you that calling individuals out (Put up or shut up!) is great political theater, and as Simon/Ehrlich tells us can have lasting and perhaps disproportionate impact, but it is something different than a prediction market.

1- number of people/$$ spent on human migration

2- measurable increase in catastrophic storm damage

3- measurable increased stress on water delivery systems

etc….

Otherwise, why not just bet black holes and keep it friendly and apolitical? Obviously the reason this is happening is *precisely* because of politics.

“The auction market does not depend upon classical efficient market theory as much as it depends upon people’s natural caution — the fact that losing hurts more than winning gives pleasure. This tends to tone down “wild” claims that normally take precedence either in a group of similarly-minded people or in the race to be noticed by the media.”

http://www.realclimate.org/index.php?p=161#comment-2451

Beyond whatever scientific value can be created, it helps the public identify who’s making wild claims. Put up or shut up is a useful concept.

BTW, if you want an example of why you have to carefully define such bets here is one which Simon lost http://www.forestry.auburn.edu/sfnmc/web/bet.html