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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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.
Based on what I’m reading at Lucia’s from comments (BTW really gives an insight to the way teamsters actually THINK)
http://rankexploits.com/musings/2012/screening-bias-cartoon-form/
There is no chance the Gergis paper will be re-submitted. CA/SMac will totally destroy it
Here is my comparison of Hansen et al (1988) VS observation => http://bit.ly/JPvWx1
Evidently being right is not in his job description.
Who are you going to believe? A model or actual data? The answer has clear for a decade and a half. The consensus is the model.
chicagoblack says:
“Modelling accuracy changes over time”
Modelling inaccuracies become apparent over time. Nothing could be more relevant than showing the “Team”, then and now, cannot predict climate and have over-estimated the warming from CO2 by 150 percent.
Irrelevant? Give us a break, Dude.
chicagoblack says:
Also, Models are not a “measurement device” for anything. GIGO
@Chicagoblack
The problem is that, as with the IPCC executive summary, the findings are political in nature. We are already told that catestrophic global warming was emminent based on their finding. Now we see how far off their models were, and continue to be. Yet the finding does not change. The political is driving the scientific. Your comment “Modeling accuracy changes over time and improvements are obviously made just like with other measurement techniques, climate or otherwise.” is irrelevant. Even if the models were re-made to show 100% accuracy in hindcast and observed it would not change the political intent to fundimentally change social progress. Capitalism and the western way of life is the target.
IMHO.
Linear extrapolation fails every time.
chicagoblack says:
Irrelevant. The Farmer’s Almanac predicted ….
Good comparison though you didn’t mean it that way. Hansen is about as scientific as the Almanac when it comes to predictions and he’s still trying to justify the ’88 “projections”. They might even have a better a track record than him. Can’t be any worse than the Brits though.
The graph is mislabeled. The blue line represents the projected increase in carbon taxes, green subsidies and climate science funding and should be labeled in dollars. Hansen was spot on with this model.
Question: Does it really mean 150% ?
OR
“Temperatures are lower than Hansen forecast they would be if humans disappeared off the planet twelve years ago.”
http://stevengoddard.wordpress.com/2012/06/15/clarifying-hansens-scenarios-worse-than-it-seems/
Steven Goddard points out that Hansen’s Scenario C prediction is worse than thought-
“Scenario C means essentially zero emissions after the year 2000 i.e. “net climate forcing ceases to increase after the year 2000.”
http://stevengoddard.wordpress.com/2012/06/15/clarifying-hansens-scenarios-worse-than-it-seems/
I wonder how long before someone in the press says, “Hey, look at this. If we go back 20 years and look at the IPCC predictions, they’re all wrong.”
Silly me. That would only happen if there were still reporters and journalists instead of advocates.
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.
Hansen did use a 4.2°C per doubling sensitivity – now thought to be too high, with ~3°C the current estimate. That resulted in a slight overestimate of warming, with the model showing an overestimate of ~20% when run with actual forcings. It’s noteworthy that Hansen’s 1988 regional temperature distribution predictions (regional predictions being an issue many folks seem to raise with climate models) are quite accurate (see http://pubs.giss.nasa.gov/docs/1988/1988_Hansen_etal.pdf, Plate 2).
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.
chicagoblack says:
June 15, 2012 at 9:10 am
Irrelevant. The Farmer’s Almanac predicted last year would be colder but it wasn’t.
The difference is that the FA is basically just a long-range weather forecast. I don’t know what % their accuracy rating is, but it’s a good bet that it’s far higher than Hansen and his fellow climate prognosticators is. The reason for that is that Hansen and crew have the mistaken notion that our C02 is somehow driving climate. Since the very basis for their models is false, no amount of fiddling with them or adjusting is going to make them any better than what they are and always have been: pure unadulterated horse manure.
It’s more than 150% wrong because the data are made up! No correction for Urban Heat Island effect, but adjusted so to maximize warming trend! It’s actually been cooling since 1998, so that means it’s infinite times wrong during that time frame!
Speaking of 1988, that was the hottest and driest summer since the Dust Bowl in the midwest. Nothing remotely close since then. I’ve seen some talk of drought this year, and the drought monitor does show a lot of drought. But I don’t know what drought they’re monitoring! 2010 and 2011 were the wettest two year period on record, and precipitation is only barely below normal for 2012. How in the heck can we be in a drought? It’s like the fake Minnesota drought last month and the fake UK drought this spring… soon as we get a dry period, they start hyping of a drought. One thunderstorm is all it takes to erase the entire yearly precipitation deficit!
He should apologize to Congress for the damage to the world economies he nearly caused, and then he should retire to the Maldives where is nonsense is better appreciated.
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.”
Just to complete your argument then, could you give in watts per metre squared, the reduction in forcing due to the reductions of CFC’s? I just want to see how the numbers compare.
Not to worry, increased warming will “return with a vengeance” later this decade (or maybe the decade after)! Just you wait and see. It’s not only coming back, but it’ll be mad as hell and looking to kick sceptic rear!
It’s worse than just being wrong. If we had done what Hansen wanted in 1988, even without any impact at this point he could be saying “it’s working, look how much warming we’ve avoided!” and there’d be no way to prove it hadn’t been the mitigation activities. Think of the accolades the team could be glowing in right now if it weren’t for them meddling kids ……. er …. skeptics. No wonder they’re PO’d.
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.”
So now forcings are political in nature? All this time I though forcing referred to a physical process happening in real time. Silly me! Well, as long as there was a consensus….
KR, thanks for that explanation. If I may summarize:
1. Hansen used sensistivity that was way too high (ie was wrong)
2. Hansen assumed all other factors would remain constant (ie was wrong)
3. Yet proclaimed the science to be settled (ie was wrong)
KR
“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.”
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Ha ha ha ha