RTFWR or... No more Mr. Nice Bunny

Ever go to look something up and get the wrong year or page? Some of Eli's best ideas have come from that, but Willis Eschenbach gets the wrong decade, the wrong page, and by gosh the wrong journal. As of 2006, Willis wins the 2004 Douglas Corrigan RTFWR prize.

Eli has several posts on Hansen et al. (Fung, Lacis, Rind Lebedeff, Ruedy and Russell playing et and al. on Broadway) J. Geophys. Res. 93 (1988) 9341 a somewhat key paper as it predicted the course of global temperatures early on, and wadda u now, did pretty well at it. The results were part of Hansen's testimonies to the US Congress in the late 80s. The basis of that testimony was the GISS climate model and three scenerios, called A, B and C.

A number of foolish people have stuck their fingers up their nose on this. Pat Michaels is famous for having used his eraser to push the predictions of scenerio B and C into the memory hole. Pat, the Holiday Inn climatologist of Virginia, claimed that Hansen had never said that B was the most likely scenerio and that Scenerio A was the one. Rabett Research went and got the paper showing that Pat is either a stone liar or had not RTFR (handy phrase that).

Then some worthies started to chant that Hansen had never said anything about B being most likely in his congressional testimony. Rabett Research key operatives renewed their Library of Congress cards (We love using it as ID at airports, and sometimes they take it, but the spoilsports have stamped not official government ID on an official government ID. Drat.), and by gum Jim Hansen did too (the whole thing is so damned childish, what do you think I would say?)

Then we got to the stupidity that the forcings Hansen predicted for the scenerios were all wrong. Hmm, that looks pretty good to me. So now we get a visit from the amazing Willis

First, Eli, take a deep breath and stop trying to insult me. I have RTFR, many times, and obviously much more closely than you have. For example, you keep claiming that Scenario C goes flat in 2000, as shown in this graph on your web site.

Hey Willis, that looks pretty flat up there from the Hansen et al. paper you did manage to read showing the Scenerios A, B and C from the one you left on the shelves. Further with Willis:

But Hansen clearly states in the FR that the "Slow growth [Scenario C] assumes that the annual increment of airborne CO2 will average 1.6 ppm until 2025, after which it will decline linearly to zero in 2100."

That gem comes from the 1998 paper, not the one under discussion. A prediction of what the 1998 temperatures were going to be in 1998, being a bit less impressive. In 1998 Hansen et al (Sato, Glascoe and our old friend Ruedy, doin the et al bit in the revival) looked at what happened in the past (see above) and came up with new scenerios, also called A, B and C after their grandpappies (shown below)But Willis really shakes my whiskers with

RTFR yourself, and then remember your foolish arrogance next time you get ready to claim that you are a prescient lagomorph. Your graph, linked above, is a joke. It shows less than one ppmv difference between the CO2 levels in the three scenarios except for your mistaken flattening of Scenario C in 2000. Think about it, Eli. Do you really believe that Hansen went to all the trouble to create three separate CO2 scenarios that would only differ by 1 ppmv after a run of fifty years? Get real!

So the mechanical bunny went and got the 1998 predictions for CO2 forcing (top figure).

You can see how the CO2 forcing matched up with the data in an earlier post. Spot on. Sorry Willis.

Hansen, et al, went to all the trouble of creating a series of three scenerios that would not differ by 1.5 ppm in 42 years because a) they had data from 1958 to 1987 and one does want to match reality in all three scenerios and b) they wanted to make realistic short term predictions. The CO2 forcings start diverging in 2000.

It is true, that if you look at the words, the CO2 mixing ratio growth in Scenerio A is exponential and in B it is linear, a favorite distraction of an unworthy competitor, but one should not fall into the well known fallacy of Pielke. Remember class, for small changes (10-20 ppm in 300) a linear change closely approximates an exponential one.

Honest Jim Hansen being the sportsman he is shows the rubes part of the machinery.

The climate model we employ has a global mean surface air equilibrium sensitivity of 4.2 C for doubled CO2. Other recent GCMs yield equilibrium sensitivities of 2.5-5.5 C.....

Forecast temperature trends for time scales of a few decades or less are not very sensitive to the model's equilibrium climate sensitivity (reference provided). Therefore climate sensitivity would have to be much smaller than 4.2 C, say 1.5 to 2 C, in order for us to modify our conclusions significantly.