From their Die kalte Sonne website, Professor Fritz Vahrenholt and Dr. Sebastian Lüning put up this guest Post by Prof. Jan-Erik Solheim (Oslo) on Hansen’s 1988 forecast, and show that Hansen was and is, way off the mark. h/t to Pierre Gosselin of No Tricks Zone and WUWT reader tips.
Figure 1: Temperature forecast Hansen’s group from the year 1988. The various scenarios are 1.5% CO 2 increase (blue), constant increase in CO 2 emissions (green) and stagnant CO 2 emissions (red). In reality, the increase in CO 2 emissions by as much as 2.5%, which would correspond to the scenario above the blue curve. The black curve is the ultimate real-measured temperature (rolling 5-year average). Hansen’s model overestimates the temperature by 1.9 ° C, which is a whopping 150% wrong. Figure supplemented by Hansen et al. (1988) .
One of the most important publications on the “dangerous anthropogenic climate change” is that of James Hansen and colleagues from the year 1988, in the Journal of Geophysical Research published. The title of the work is (in German translation) “Global climate change, according to the prediction of the Goddard Institute for Space Studies.”
In this publication, Hansen and colleagues present the GISS Model II, with which they simulate climate change as a result of concentration changes of atmospheric trace gases and particulate matter (aerosols). The scientists here are three scenarios:
A: increase in CO 2 emissions by 1.5% per year
B: constant increase in CO 2 emissions after 2000
C: No increase in CO 2 emissions after 2000
The CO 2 emissions since 2000 to about 2.5 percent per year has increased, so that we would expect according to the Hansen paper a temperature rise, which should be stronger than in model A. Figure 1 shows the three Hansen scenarios and the real measured global temperature curve are shown. The protruding beyond Scenario A arrow represents the temperature value that the Hansen team would have predicted on the basis of a CO 2 increase of 2.5%. Be increased according to the Hansen’s forecast, the temperature would have compared to the same level in the 1970s by 1.5 ° C. In truth, however, the temperature has increased by only 0.6 ° C.
It is apparent that the next to it by the Hansen group in 1988 modeled temperature prediction by about 150%. It is extremely regrettable that precisely this type of modeling of our politicians is still regarded as a reliable climate prediction.
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Olen says:
June 15, 2012 at 9:19 am
Evidently being right is not in his job description.
I take it you mean the German author of this hatchet job, he gets just about everything wrong about the Hansen et al. paper. I find it hard to believe that they actually read it. It’s fine to criticize the work by comparison with the actual data, but at least get the facts right, at the time Hansen described scenario B as ‘perhaps the most plausible of the three cases’. So to linearly (not log) increase the scenario A value as if it was due to 1.5% growth in CO2 emissions (which it wasn’t) and claim that Hansen’s prediction was out by 150% is nonsense.
KR says:
June 15, 2012 at 9:50 am
A fascinating, and incorrect, post. Given actual CO2 emissions and the reduction in greenhouse-active CFC’s due to the Montreal Protocol, forcings have been closest to the “B” scenario – about 5-10% below “B” scenario total forcing. Not the “A” scenario as argued here. That is a strawman argument (http://en.wikipedia.org/wiki/Straw_man). It might be reasonable to argue that Hansen didn’t predict economics very well, but then again this was a _climate_ model, not an _economic_ model.
Assuming that CO2 is the only active greenhouse gas is a common, but serious, error. CFC decreases were huge.
The IPCC seems to have declared that chlorofluorocarbons were a “greenhouse gas” without any observations to back that up.
@Chicagoblack You said “Modeling accuracy changes over time and improvements are obviously made just like with other measurement techniques, climate or otherwise.”
No, it doesn’t. “Climate” models will always be wrong – there are just too many variables to accurately predict climate – they can’t even accurately predict weather yet, lol!!!
Warmists would argue that it’s all that natural/Chinese SO2 cooling that is offsetting the warming and if we hadn’t had the cooling we’d be in trouble. Of course the opposite would also apply, if we hadn’t had the warming we’d be what? Colder than the Little Ice Age?
KR is saying that if Hansen’s paper had been accurate, it would have been accurate….
I agree.
Are the “Observed” data from satellites, surface stations (complete with lousy sitings, reduced high-elevation and high-latitude sites, disappearing sites, and “adjustments”), or a mix of both?
KR says:
June 15, 2012 at 9:50 am
A fascinating, and incorrect, post. Given actual CO2 emissions and the reduction in greenhouse-active CFC’s due to the Montreal Protocol, forcings have been closest to the “B” scenario – about 5-10% below “B” scenario total forcing. Not the “A” scenario as argued here. That is a strawman argument.
Hansen’s predictions were based solely on CO2 levels, hence the post is both fascinating and accurate.
Your comment is a red herring.
chicagoblack says:
June 15, 2012 at 9:10 am
Irrelevant. The Farmer’s Almanac predicted last year would be colder but it wasn’t. Modeling accuracy changes over time and improvements are obviously made just like with other measurement techniques, climate or otherwise.
So, by the sheer age of the Almanac’s model it should be quite accurate but, but by your own argument it isn’t.
Q.E.D.
While I have little interest in defending Hansen from anything, I think this “150% wrong” is a math error and we can do better than that. I assume the 150% comes from “projecting” 1.5 ° C while observations report 0.6 ° C In my book, the observation is 60% lower than the projection. Had the the observation reported no change, that would be a 100% error and the offered 150% error means that observation should be a drop of 0.75 ° C.
We do not have to twist percentages around to show that Hansen’s projections are wrong. Exaggeration is not necessary, that’s for people like Stephen Schneider.
Even better – I claim percentages beyond 20 or 30% are the work of the devil and should be avoided unless you like to play with fire and brimstone.
KR says:
June 15, 2012 at 9:50 am
The sensitivity estimate he used in 1988 (considered reasonable then) was rather too high, and considering actual forcings (given political and economic developments) close to the “B” scenario, Hansen’s 1988 model was surprisingly good.
I can tell you have been reading SkepticalScience, haven’t you? Their patently absurd claim is no more true having restated it. When your statistical argument doesn’t even pass the eyeball test you really should not make it. Real world measurement OBVIOUSLY is a much closer fit to Scenario C than it is to A or B. Please look at the graph again.
Hey KR, as someone else asked, what are the Watts per square meter of forcing from CFCs, and by how much as that decreased over time?
Also note how we are beneath Scenario C (even with “corrected” forcing, we’d be right on the C line, and following its shape), which is absolutely no emissions at all after 2000. So what does that tell you?
Come on guys/gals…..you know that we’ve all used a mulligan a time or two in golf….JH just uses one whenever he wants!! (ie GISS temp. record, 1988 testimony, arrest -> release ->arrest -> release…etc….)
davidmhoffer says:
June 15, 2012 at 10:23 am
KR, thanks for that explanation. If I may summarize:
1. Hansen used sensistivity that was way too high (ie was wrong)
If I may summarize: he used the accepted value of the time, which now appears to have been too high compared with the present value.
2. Hansen assumed all other factors would remain constant (ie was wrong)
He didn’t, read the paper. He quite explicitly made various assumptions about future emissions, volcanoes etc.
3. Yet proclaimed the science to be settled (ie was wrong)
He didn’t! In fact he said:
“Major improvements are needed in our understanding of the climate system and our ability to predict climate change.
We conclude that there is an urgent need for global measurements in order to improve knowledge of climate forcing mechanisms and climate feedback processes.”
Making such demonstrably false statements as you have done here certainly diminishes any credibility you may have had.
techgm says:
June 15, 2012 at 10:45 am
Are the “Observed” data from satellites, surface stations (complete with lousy sitings, reduced high-elevation and high-latitude sites, disappearing sites, and “adjustments”), or a mix of both?
Probably pulled from thin air like the rest of the piece!
What temperature measure are they using? I thought that by most measures 2005 and 2010 were as hot if not hotter than 1998.
Phil. says:
June 15, 2012 at 10:26 am
You really don’t understand what Hansen was saying, do you?
Actual CO2 is above scenario A. That means that Hansen is wrong and continues to be wrong until such time as he withdraws the paper and publically admits to lying to Congress for financial gain.
KR,
If we assume that the reduction in CFC’s have the net result of making Scenerio B the closest to reality (ie CO2 increase is offset by CFC decrease), which is what I think you are saying, then I’ll agree that the 150% wrong claim may be hyperbole, but it still looks like Hansen is wrong. Real temps are not close to Scenerio B predictions.
Greg Tuttle,
CFC’s have long been know to have a GHG effect. My personal opinion is that the Montreal Protocol will turn out to be a good thing – even if by accident – with regard to warming. It doesn’t seem to have done much for what it was intended to do.
Increasing CO2 amplifies the delusions of the susceptible, plenty of evidence for that since belief in anthropogenic climate change has paralleled banking delusions, European single currency delusions and global government delusions of the UN. All follow the same hockey stick, but global temperature doesn’t.
Hansen will soon be made an FRS. When you get things this wrong that’s how you are rewarded. Look at Paul Ehrlich who has been been made an FRS. I cannot think of anyone whose ‘prophecies’ have been more wrong than his: in 1980 he predicted 50% of all species would extinct by 2000 and everything extinct by 2015. Let alone his predictions about starvation etc. He probably thinks that swallows hibernate in winter.
When you compare simulation projections to observations there are several tings you have to do in order to complete a competent and objective analysis.
First, you have to understand that simulations provide a conditional prediction:
IF, future forcing looks like X, and IF cilimate sensitivity is Y, then we predict a temperature
of Z ( +- std)
The first problem you face in evaluating a projection is understanding that it is not and cannot
be a controlled experiment. That is, we cannot force the IF statements to be true. So,
we typically do sensitivity testing or scenario testing. The closest thing I can think of
is war gaming analysis. The kind of analysis and simulation that goes on prior to a armed
conflict.
To evaluate hansens projection we first have to find the scenario that is closest to the projected
forcings. That is scenario B, not C and not A. Then we have to understand that hansen used
the wrong figure for climate sensitivity. His figure was more likely than not too high.
What’s that mean? what can we conclude from the simulation? we can say that a climate sensitivity of 4.2 is likely to be too high. We can say that the simulation needs work. we can
also conclude that scenario development is one of the weakest parts of the process.
We can also conclude that testing more scenarios is a good idea if we want to grade simulations and improve simulations
What would be interesting is this. It would be interesting to take a newer version of ModelE ( sensitivity is 2.7) and re run Hansens experiment with the following inputs
1) scenario A, B and C
2) actual forcings during the observation period.
How dare anyone disparage the Farmer’s Almanac by comparing it to Hansen’s work? The Farmer’s Almanac has a far better accuracy. Heck, even Punxsutawney Phil gives an honest forecast.
Reduction in CFC’s has not previously been put forward as a reduction in forcing, given that CFC’s were not originally considered as greenhouse gases and by 1988 the Montreal Protocol was already having an impact in reducing these gases. To use this as an argument for dismissing Scenario A is misdirection.
Yes, Hansen has suggested that Scenario B was the most likely, but that was based (quite specifically, IIRC) on reductions in CO2 emission growth. This was his whole point in arguing that Kyoto was irrelevant because this was not going to be enough of a brake on CO2 emissions and we (the western world) should have been doing more
The fact is that the actual emissions on CO2 have outstripped scenario A, yet we have not seen anything like the increase in temperatures that this increase was supposed to have caused. Such a falsification (which is precisely what it is) pretty well demands major revision of the model – not the tinkering around the edges that Hansen and supporters have been trying to do.
My Real Science comment on this: Let’s assume he actually knew roughly that temps would follow scenario C — regardless of what happens with CO2. And thus that he also knew that what we did on CO2 emissions would have no effect at all. So, IF we at the time instituted drastic CO2 cuts, he could say that his cuts worked, because temps would be doing what they are doing now. This would be used to justify even more cuts, as we head then toward the leftist dream of apocalyptic de-industrialization.
What if at the time he didn’t get govts to institute crazy CO2 cuts? For one, at the time, Hansen was doubling down, was trying to rush the people and govts into implementing his whacky economy-busting ideas.
Secondly, he probably just wasn’t going to bother with thinking that far ahead — nearly 25 years now. But now he needs to pay the piper for his demonstrated proven bullshit.
There’s a good discussion of the actual forcings at http://www.realclimate.org/index.php/archives/2007/05/hansens-1988-projections/ – and what actually happened are forcings slightly below Scenario B (within ~0.1 W/m^2). See this figure showing scenario and actual forcings: http://www.realclimate.org/images/Hansen88_forc.jpg
Again, the various scenarios are “what-if”s, the actual model is how the climate would respond to various forcing levels. On that measure Hansen 1988 holds up surprisingly well for a 25 year old model.
And, to repeat – while CO2 has progressed roughly as both scenarios A and B projected, we have not gone through Scenario A, due primarily to CFC reductions and a rather lower than expected amount of methane. Arguing that Hansen’s model was flawed based upon events that didn’t happen is a completely bogus strawman argument.
Hansen does not care about observations or the science. Hansen and his cohorts exaggerated, manipulate, and cherry pick data to push the extreme AGW agenda.
The planet’s response to a change in forcing is to resist the change (negative feedback) as confirmed by Lindzen and Choi’s analysis of top of the atmosphere radiation vs ocean surface temperature changes. Hansen and the IPCC require the planet to amplify forcing changes (positive feedback) to create the scary extreme warming scenario that the jihad environmentalists use to justify the Western governments spending trillions of dollars on “green scams” that do not significantly reduce CO2 emissions which is not a problem anyway as plants eat CO2. Western governments are deeply in debt and losing the battle for jobs with Asia.
When logic, reason, science, and economic reality is removed from public policy the resultant is chaos.
http://www-eaps.mit.edu/faculty/lindzen/236-Lindzen-Choi-2011.pdf
On the Observational Determination of Climate Sensitivity and Its Implications
We estimate climate sensitivity from observations, using the deseasonalized fluctuations in sea surface temperatures (SSTs) and the concurrent fluctuations in the top-of-atmosphere (TOA) outgoing radiation from the ERBE (1985-1999) and CERES (2000-2008) satellite instruments. …
We argue that feedbacks are largely concentrated in the tropics, and the tropical feedbacks can be adjusted to account for their impact on the globe as a whole. Indeed, we show that including all CERES data (not just from the tropics) leads to results similar to what are obtained for the tropics alone – though with more noise. We again find that the outgoing radiation resulting from SST fluctuations exceeds the zerofeedback response thus implying negative feedback. In contrast to this, the calculated TOA outgoing radiation fluxes from 11 atmospheric models forced by the observed SST are less than the zerofeedback response, consistent with the positive feedbacks that characterize these models. The results imply that the models are exaggerating climate sensitivity.
http://www.forbes.com/sites/jamestaylor/2012/04/11/a-new-global-warming-alarmist-tactic-real-temperature-measurements-dont-matter/
A New Global Warming Alarmist Tactic: Real Temperature Measurements Don’t Matter
What do you do if you are a global warming alarmist and real-world temperatures do not warm as much as your climate model predicted? Here’s one answer: you claim that your model’s propensity to predict more warming than has actually occurred shouldn’t prejudice your faith in the same model’s future predictions. Thus, anyone who points out the truth that your climate model has failed its real-world test remains a “science denier.”
This, clearly, is the difference between “climate science” and “science deniers.” Those who adhere to “climate science” wisely realize that defining a set of real-world parameters or observations by which we can test and potentially falsify a global warming theory is irrelevant and so nineteenth century. Modern climate science has gloriously progressed far beyond such irrelevant annoyances as the Scientific Method.