Guest Post By John R. Christy of the University of Alabama at Huntsville
via Dr. Roger Pielke Sr’s blog: Climate Science
The three warm-color time series are taken from Hansen’s published testimony in June 1988 in which global surface air temperatures were projected under three scenarios by his global climate model.
The red curve follows a scenario (A) of continued emissions growth based on the previous 20 years before 1988 (which turned out to be an underestimate of actual emissions growth.) The orange represents a scenario (B) of fixed emissions at the rate achieved in the 1980s. The yellow curve portrays a scenario (C) in which “a drastic reduction” in GHG emissions is assumed for 1990-2000. The observations are global tropospheric temperatures adjusted to mimic the magnitude of surface temperature variability and trends according to published climate model simulations (i.e. a reduction in satellite anomalies by 0.83.)
After tying all time series to a 1979-83 reference mean, one can see the significant divergence in the results. (Notes: 1. observed 2010 is Jan-Jul only; 2.) tropospheric temperatures are used as the comparison metric due to many uncertainties and biases in the surface temperature record, i.e. Klotzbach et al. 2009, 2010 ; 3.) both models and observations included the 1982 eruption of El Chichon while B and C scenarios included a volcano in the mid 1990s – not too different from Mt. Pinatubo.)
The result suggests the old NASA GCM was considerably more sensitive to GHGs than is the real atmosphere since (a) the model was forced with lower GHG concentrations than actually occurred and (b) still gave a result that was significantly warmer than observations.
Correction:
Village Idiot,
“here is an opinion about AGW“
carrot eater says:
August 13, 2010 at 6:24 pm (Edit)
Robert,
The 0.83 is a cheeky ploy. Christy is assuming there is tropical tropospheric “hot spot”.
He is not assuming there is anything of the sort. The ocean has a much bigger thermal capacity than the atmosphere, and a small change in ocean temperature causes a correspondingly larger change in atmospheric temperature, which lags the ocean temp by 3 months on average.
AlexJ,
B and C were part of the original and are there to display that if we either kept CO2 at a standstill or dramatically reduced our CO2, then according to the model, our temperatures would have turned out to be higher than current. In actuality, CO2 increased and yet the model overshot the result in all 3 scenarios. If the real temperature had fallen somewhere between A and C, then the model maker would at least be able to claim that he was in the ballpark. John C’s criticism is stronger for including B and C compared to reality.
Finally Village Idiot,
the scientific method demands that a theory makes predictions / forecasts about the future and if those predictions / forecasts are wrong then………… [fill in the space yourself].
This is why he is under attack for something he said 22 years ago and this is why climate scientists will continue under attack for the continued failed prediction while currently releasing press releases and spreading alarmist stories among naive members of the public.
Can you imagine what Hansens red curve would have looked like had he known what the actual emissions of co2 was going to be? It would have looked closer to a hockey stick and he would have been even more wrong. :o)
Lets leave the scientific aspects of this blog and look at the logic !
I have a Pierce-Arrow value $1,000,000 I decide to get it repainted, I am introduced to a man who says that he is a professional painter and will paint the car for $50,000.
He gets the work !
He did not tell me he was a house painter !
Value of the car now $10,000.
I would equate this with J. Hansen, if I had asked the house painter to show me some of his work, my car would still have a value of $1,000,000
If J. Hansen is all he claims to be, lets see a exact forecast (day by day for next month) if he can tell the world that on Tuesday 14th of September 2010 at 0800 hours in New York it will start to rain and continue until 1327 hours when the wind speed will drop from 10 knots to 2.4 knots etc., THEN and only THEN will his predictions ( ah, excuse me, his self generated models) could be taken seriously for short term weather pattens.
tallbloke says:
August 14, 2010 at 12:45 am
He is not assuming there is anything of the sort. The ocean has a much bigger thermal capacity than the atmosphere, and a small change in ocean temperature causes a correspondingly larger change in atmospheric temperature, which lags the ocean temp by 3 months on average.
This is wrong. Carrot Eater is right. John Christy has, effectively, assumed that the model predictions of enhanced warming in the troposphere are correct and has adjusted the troposphere anomalies accordingly. He says as much in this extract from his post:
The observations are global tropospheric temperatures adjusted to mimic the magnitude of surface temperature variability and trends according to published climate model simulations (i.e. a reduction in satellite anomalies by 0.83.)
I’ve got a great deal of respect for both Roy Spencer and John Christy, but I’m not comfortable with this sort of thing. I’ve been very critical of Hansen’s predictions in the past but, in the interests of fairness, there are a couple of other points that should be considered.
1. As someone has already commented, Hansen gave a prediction/forecast/projection of warming and that’s what happened. We can argue about the magnitude of the warming but we can’t deny that warming has taken place. Hansen got the direction of temperature change right. Which (if any) of the solar theorists who are now trying to attribute recent warming to solar infuences predicted a 20-30 year warming trend in the 1970s or 1980s?
2. I don’t know but I assume Hansen’s 1980s model was relatively crude and it’s not clear (to me) that he correctly factored in ocean heat capacity. It’s worth noting that both surface and LT temperatures over land have increased at a faster rate than over the ocean and that land temperatures (only) show much more agreement with the Hansen prediction than do global temperatures.
I’m quite happy to argue with anyone who claims that the Hansen predictions have been validated but equally I”ll argure with anyone who claims that the predictions have been a total failure.
Professor Christy’s graph does appear to differ from Hansen’s original in that scenario B overlaps scenario A around 2015, but the relationship between scenarios A and C looks about right.
The criteria for the scenarios was clearly stated:
“Scenario A assumes continued exponential trace gas growth, scenario B assumes a reduced linear linear growth of trace gases, and scenario C assumes a rapid curtailment of trace gas emissions”
On a previous thread, warmers were insistent that the increase of CO2 concentration since c. 1950 was exponential (not linear) which may be correct because it is impossible to tell over such a short period but linear or exponential, there is no way that it can be claimed that there has been a reduction in the linear growth, let alone a rapid curtailment.
The question as to whether human GHG’s (mainly CO2) emissions are having a profound effect on the climate will not finally be answered for decades unless there is a temperature plunge in the next few years and no one wants that.
Sophistry doesn’t help the alarmists’ case.
Stokes
Is to laugh. Yeah, Hansen did a “pretty good”. He hit the target, except it was the wrong one. Scenario C is the one it should not have matched. Scenario A is closest to what happened in emissions, not C.
Say Hansen predicted that if I doubled the amount I put in my stock account over 20 years (Scenario A), I would have X and if I put nothing in (Scenario C) I would have X/2. If I wound up with X/2 after doubling the amount I put in my stock account would you say he did “pretty good”?
Show us how hitting the wrong target is “pretty good”.
An extensive oral interview with James Hansen and GCMs. October 23, 2000
“In the early 1970s, my interest was in planets, and the editor of Science invited me to write a review paper on the clouds of Venus.
…………
….I never did get that paper done for Science. So I missed that opportunity. But at the same time, Jastrow had realized that there wasn’t much money left in planetary studies. He was trying to get the Institute more directed towards practical applications. ”
http://www.aip.org/history/ohilist/24309_1.html
James Hansen interview part II
Q. If you look back over the last 20 years, how do you think climate science has changed?
A. I’m afraid that it’s changing in the sense of more emphasis on models, which I think is a mistake.
Part 2
http://www.aip.org/history/ohilist/24309_2.html
Academia nuts.
Christopher Hanley says:
Actually, that is only the summary of the general basis of each sceneario. The actual details of each are in this paper: http://pubs.giss.nasa.gov/docs/1988/1988_Hansen_etal.pdf (section 4 and appendix B). That is what allows one to determine that overall we most closely followed Scenario B.
flyfisher says:
Climate modeling doesn’t just predict by fitting to some sort of mathematical formula. It is instead an actual simulation of the climate system and it captures many of the features of the actual climate system including the chaotic behavior that is responsible for the global temperature bouncing around as you observe. Such behavior is due to things such as ENSO (El Nino – La Nina). However, because this behavior is chaotic and thus very sensitive to initial conditions, the climate is not expected to follow the exact up-and-downs of this jiggles: the behavior of this “noise” in the system should be the same only in a statistical sense between the simulation and the real climate. Indeed, simulations with perturbed initial conditions show different patterns of jiggles…but the same overall trend due to the forcings when you look over long enough times.
BarryW says: August 14, 2010 at 4:13 am
No, scenario B is the closest, roughly linear increase in CO2, with a El Chichon type volcano (we got Pinatubo). Hansen said in 1988 that B was the most plausible.
Re: Global Mean Temperature predictions
Does anyone know the absolute global mean temperature predicted by Hansen’s code (not the anomaly) – how does this compare to the “actual” absolute global mean temperature. Also, how does his code determine the global mean surface temperature? I’ve looked through the mess that is Model E and could never find out where it is they integrate the global mean surface temperature.
As an aside, it is amazing that people put so much faith in poorly documented and validated code that purports to solve highly coupled, non-linear partial differential equations (we don’t know which ones due to the poor documentation) with very approximate boundary and initial conditions, for solutions extending decades into the future. This exercise (particularly at GISS) is all just a colossal waste of taxpayer money. In my opinion, the government should consolidate all of the GCM research efforts at NCAR and zero-fund the rest of these redundant programs…
eudoxus says:
August 13, 2010 at 10:43 pm
“Hansen’s skill, however weak, was greater than yours, in any case.”
Nick Stokes says:
August 13, 2010 at 11:07 pm
“And the prediction of GMST was pretty good.”
And to the rest of the defenders of Hansen. These two comments are what seem to be representative of much of the Hansen defense. They seem to be saying, 1. You didn’t predict warming back then. And 2. Hansen was pretty close.
First, as I’ve pointed out many times, HANSEN MADE 3 DIFFERENT PREDICTIONS!!! What are the odds that some of the prediction may resemble reality in some way? Well, pretty good seeing that we was all over the board with GHG’s and temps. Let’s review, his predicted temp trend look a lot like scenario 3, yet his GHG prediction is similar to scenario 2. Unless, you want to refer to his 2006 paper regarding himself. You guys can’t seriously use Hansen’s paper as proof he’s right because he thinks he’s right. That’s ludicrous. If you prefer to use land temps as opposed to sat. data, find some other data set that would collaborate Hansen’s. Oh, what’s that you say? It doesn’t appear there are any like his? Here is the other land temp trend since the greatest increase of observed temps. Given that they share 90% of the same temps, there is absolutely no way they can both be correct. One obviously has a bias. Q,”Dr. Hansen, were you correct on your 1988 predictions” A,”Of course I was, all I had to do was tweak with the temps a bit. Here’s my 2006 study that says I was right.”<——————————– Unbelievable, but some here and other places actually do this.
Here's why it doesn't matter if Dr. Christy was as skilled as Hansen in predicting the state of climate 20 years latter. We didn't pass any laws based on Christy's erroneous judgment. We passed laws that literally affected the entire world based on Hansen's erroneous judgment. Apparently, the twit doesn't know how to say "I don't know." Even when it is obvious he doesn't.
I predict some will agree with me on this, but others may not. I also predict some will simply ignore and disregard this post. I'll submit this to congress and see if there are any industries, careers, jobs, lives and livelihoods we can destroy based on my predictive prowess. I'll probably do a study that looks into whether I was correct or not later and we can use that as justification for the damage done.
Dang, forgot to include the link that shows the 2 land temp groups and the divergence.
http://www.woodfortrees.org/plot/gistemp/from:1999/trend/plot/hadcrut3gl/from:1999/trend
Frank K. says: August 14, 2010 at 6:06 am
Does anyone know the absolute global mean temperature predicted by Hansen’s code (not the anomaly) – how does this compare to the “actual” absolute global mean temperature.
Hansen doesn’t do that. He has a standing post at GISS on why it’s virtually impossible to even define a global surface absolute temperature, and why anomalies are essential.
Very similar analysis here with Hansen’s original graphs:
http://tinyurl.com/6cms9f
JinOH says:
August 13, 2010 at 4:20 pm
Hansan has help. Lots of help. Billions and billions of dollars worth of help. Not all to him, of course, but to people and groups that think along the same lines.
Dr. Dave says:
August 13, 2010 at 6:50 pm
Who are you assuming will be in the new administration? With maybe one or two exceptions the likely candidates will probably continue with business as usual.
Nick Stokes says:
August 14, 2010 at 6:03 am
BarryW says: August 14, 2010 at 4:13 am
No, scenario B is the closest, roughly linear increase in CO2, with a El Chichon type volcano (we got Pinatubo). Hansen said in 1988 that B was the most plausible.
Wrong. Emissions have been exponential. The fact that the CO2 rise has not been is just one more example of the failure of Hansen to understand the climate system. The emissions that he has actively tried to reduce have followed scenario A (or worse). I love to see this kind of cognitive dissonance. It shows how CAGWers bend reality to fit their beliefs. Very telling.
Instead of scrapping the space shuttle, NASA should scrap GISS.
eudoxus says:
August 13, 2010 at 10:43 pm
Dear Prof. Christy,
What were your predictions of global temperature through 2020 in 1988? You didn’t graphs those. As I recall, your original claim, based on your original analysis of satellite data, asserted there was no global warming tread. I take it that your current argument is that the earth is warming but not as fast as Hansen predicted it would in 1988, but you do now agree with him that the earth is warming. Do you agree the surface of the earth is warming? Is there something in the UAH record that suggests the surface of the earth is not warming?
Regarding skill, in 1988, even by your UAH troposphere analysis, Hansen was correct in predicting the earth would enter a period of observable warming. You denied it for many years and for many reasons. But now your UAH data shows it.
Hansen’s skill, however weak, was greater than yours, in any case.
—-
Please. Only those that offer counter predictions are allowed to debate this? Yeah, that’s science at its best. BTW, based on what I’ve read from Christy he HAS clearly stated that the Earth is warming, just not primarily due to human influences.
Your final paragraph is even more precious. So as long as I get the sign of a problem right, I’ve got the right answer?! OK, I predict US GDP will grow for the rest of the year. When do I get my Nobel? Hansen’s slope is clearly wrong and even more so when you compare the actual CO2 emissions and the predicted temperatures.
If Hansen had been in charge of the Apollo Program the moon landing would have been in Fort Lauderdale.
carrot eater says:
August 13, 2010 at 6:24 pm
“[…]So basically, Christy assumes the models are correct, (and also that UAH/RSS are correct), and ends up deciding the models are incorrect. ”
Would that not constitute a 100% proof by contradiction?