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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Bill Tuttle – “Hansen’s predictions were based solely on CO2 levels, hence the post is both fascinating and accurate.”
Actually, no. From the Hansen 1988 abstract (http://pubs.giss.nasa.gov/docs/1988/1988_Hansen_etal.pdf):
I have no idea where you got that misconception. But it’s quite wrong.
Phil. says:
June 15, 2012 at 11:04 am
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)
***************
Phil;
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.>>>>
He used a value that he was a big part in arriving at and promoted it heavily, and it was…. wrong.
Phil;
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.>>>>>
The assumptions he made about future emissions were LOWER than actual emissions, so his predictions should have been even HIGHER. Again, he was….. wrong.
Phil;
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.”
>>>>>>>>>>>>>>>>
He has been, and repeatedly so, part of the “hockey team” meme that the “science is settled” that action is “urgent” and has even advocated that those who disagree be put into jail. I judge him not by the caveats in this single paper, but his behaviour over all since then which shows quite conclusively that he continues to promote his clearly WRONG paper as if it was right, comes up with weasel word explanations for his errors to spin them as something other than errors, and has become more vociferous about his demands for action on climate issues, not less.
Phil;
Making such demonstrably false statements as you have done here certainly diminishes any credibility you may have had.>>>>
LOL. Like defending Hansen to anyone who has actually taken the time to look into his work and the facts in any amount of detail confers any credibility upon you. I stand by my remarks.
Please include a link for the measurements of atmospheric CFC levels from 1988 to present. Otherwise, admit that you just made that up.
KR says:
June 15, 2012 at 11:53 am
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
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Sorry, AND I’m to give RC page hits…when they censor and delete my posts?
Let them come here
This is pretty good from CA>
http://climateaudit.org/2008/01/16/thoughts-on-hansen-et-al-1988/
One not so minor note: What were these scenarios, and how likely did Hansen feel they were? From Hansen 1988:
Scenario A: “…assumes that growth rates of trace gas emissions … will continue indefinitely […] since it is exponential, must eventually be on the high side of reality…”
Scenario C: “…a more drastic curtailment of emissions than has generally been imagined, it represents elimination of CFC emissions by 2000 and reduction of CO2 and other trace gas emissions to such a level that the annual growth rates are zero…by 2000”
Scenario B: “…is perhaps the most plausible of the three cases.”
And interestingly enough, we’re running quite close to Scenario B. Pat Michaels was wrong to claim we were on Scenario A 15 years ago, testifying before Congress. And the opening post is just as wrong to claim it now.
which is a whopping 150% wrong
You can’t be more than 100% wrong!
KR, you can’t differentiate CO2from the Scenario, it’s the whole point. If he got the CO2 pretty close in Scenario A and B and the temperature pretty close in C that doesn’t equate to a mostly correct model.
Hansen’s scenarios show quite plainly that his assumed forcing of CO2 is wrong. His actual temperature model didn’t approach reality until he removed CO2 as a forcing.
Hey, KR, would you mind telling me what forecasts wouldn’t be “surprisingly good” when you allowed for the things the forecaster was wrong about?
Every forecast would be “surprisingly good” under those conditions, which is why your post is useless. Because you see, the whole point of a forecast is to see how good your understanding of a process is based on your forecast at that time. If you’re allowed to go back and essentially redo it and incorporate all the things you failed to forecast, it kind of defeats the purpose.
I guess you have to leave it to a ‘climate science’ type to essentially come up with the idea that forecast is “surprisingly good” so long as you incorporate all the things the forecaster failed to, you know, forecast…
Well, it doesn’t explicitly say so, but is this using HadCRU3 as the ultimate real-world temps? Looks like it to me, given the 1998 peak. If that’s the case, it seems a bit odd to compare a projection based on GISS temperature data to anything other than the up-to-date GISS data.
Forcing valuesfor the various gases can be found on http://www.esrl.noaa.gov/gmd/aggi/ – increases shown there from 1988 to 2010 are 0.71 W/m^2 (a bit less than some other references, mind you), of which CO2 represents ~0.56 W/m^2.
Hansen 1988 scenarios for that period were around:
A: 0.6 CO2, another 0.8 from CFC’s, methane, N2O, etc. ~1.45 W/m^2
B: ~0.6 CO2, 0.4 from other gases. A bit under 1 W/m^2.
C: ~0.4 total, mostly CO2. 0.4 W/m^2.
The various trace gases forcings are less than half of what was considered under Scenario B, and 1/4 that of Scenario A.
Also – did Hansen’s 1988 projection use a 5-year moving average? If not, it would seem a bit odd to do so when comparing against temperature data.
Dave H;
If that’s the case, it seems a bit odd to compare a projection based on GISS temperature data to anything other than the up-to-date GISS data.
Dave H;
Also – did Hansen’s 1988 projection use a 5-year moving average? If not, it would seem a bit odd to do so when comparing against temperature data
>>>>>>>>>>>>
What seems a bit odd is that someone can make predictions so completely wrong, and yet people turn up to try and justify by ask silly questions that, even if they were correct, would make nearly no difference to the end result anyway
WHICH WAS THAT HANSEN WAS COMPLETELY AND TOTALY WRONG!
Because Hansen did not include CFCs in his model calculations to produce this infamous graph,he CANNOT now subtract them out to get a better fit with his CO2 graph. If he is to do that properly, then he would have to show a graph that included the warming effect of the CFCs which would generate a warming curve significantly higher than curve A. Subtraction of the CFC’s effect then lead right back to his curve A. His graph is specifically calculated for CO2, there is NO effect of CFCs in his graph for which a subtraction would be valid.
I predicted a score in a hocky game in which, had the home team scored three more goals, and the visiting team two less, and the game had ended in the second period, and the score from the previous game has been added to this game, my prediction would have been correct.
KR says:
Ya know KR….I wouldn’t trust Hansen if he was spot on.
IMO He started off a crook…. [ air conditioner ] and he finished as a crook …
http://www.soros.org/resources/articles_publications/publications/annual_20070731/a_complete.pdf
Page 143 :
note: The Strategic Opportunities Fund includes grants related to Hurricane Katrina ($1,652,841); media policy ($1,060,000); and politicization of science ($720,000).
He’s not a scientist -he’s a “playa”
Phil & KR (and even Mosh) are bright chaps, they are fully capable of understanding simple arithmetic, pre-industrial levels of CO2 were around 280ppm, today the level is 395ppm, a rise of 115ppm or 41%. But CO2 forcing is logarithmic, a 41% rise represents around 70% of the forcing due to CO2 doubling, most bright chaps, even including Hansen, agree that forcing from a CO2 doubling is in the range 1-1.5ºC. 70% of that range is 0.7-1ºC. I wonder what the observed rise in temperature has been since pre-industrial times?, well blow me down, at 0.8ºC it falls exactly in that range! What does this observation mean for those that argue that climate sensitivity is greater than 1, given a century’s worth of data observations, not a lot!
Are you sitting comfortably?, because there’s more, let’s examine what’s happened since 1997 when CO2 was around 360ppm, the rise since then is 35ppm. Yes, that’s right, almost 10% of ALL THE CO2 in the atmosphere has been added since 1997! Again, CO2 forcing is logarithmic, a 10% rise represents around 18% rise in forcing from CO2 doubling, so assuming no other factors global temperature should have risen 18% of 1-1.5ºC or 0.18-0.27ºC since 1997. Again I wonder what the observed rise has been in those 15 years, strike a light, with baselines adjusted the mean of HadCrut3, GISStemp, RSS & UAH gives 0.05ºC, somewhat outside (lower) than the expected range calculated above. Those that argue that climate sensitivity is greater than 1 now have a greater than decadal observation which appears to suggest precisely the opposite!
Climate sensitivity greater than 1 is not supported by multi decadal observations, I suggest that Mr Nuccitelli and Mr Cook might like to reconsider their support for Mr Hansen, because observations would indicate that temperature, like sea level rise, ocean heat content rise and net ice loss just isn’t following the script…
I do believe nuclearcannoli has delivered the sweet cream with this one: I guess you have to leave it to a ‘climate science’ type to essentially come up with the idea that forecast is “surprisingly good” so long as you incorporate all the things the forecaster failed to, you know, forecast…
On another note, it appears based on the translated post linked above that the European “consensus” is crumbling. Of course, I don’t have the data to back up that statement, but hey, it’s climate science!
KR says:
June 15, 2012 at 11:53 am
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.
—–
CFC reductions?
Try again.
http://en.wikipedia.org/wiki/File:AYool_CFC-11_history.png
http://ds.data.jma.go.jp/ghg/kanshi/ghgp/cfcs_e.html
CFCs are more or less flat for the past 2 decades.
Why is methane less than expected? If methane is less than expected because the model expected rising temperatures to release more methane, that is a failure of the model.
What I really like about actual temperatures trending lower than Scenario C is that Scenario C was the one with CO2 emissions stopping in 2000.
The take away? Doing nothing has been better than completely stopping CO2!
Have these people been reading Steven Goddard’s site again?…..
…..Steve’s been doing this forever, now they catch up!
davidmhoffer says:
June 15, 2012 at 12:04 pm
LOL. Like defending Hansen to anyone who has actually taken the time to look into his work and the facts in any amount of detail confers any credibility upon you. I stand by my remarks.
Your claim to have taken the time to look into his work and the facts are belied by the errors you have made. This post referred to the 1988 paper and demonstrably is seriously wrong, your comments above are wrong also, trying to cover your mistakes up doesn’t help.
Another way of looking at it, when Hansen made his projections, he assumed that the only non-zero forcing was CO2 to make his graph. His graph projection already had made the assumption that the effect of CFC’s was zero. Scenario A is what warming should have occurred due to CO2 with a value of ZERO for all other forcings. The additional warming effect of the CFC’s should lead to even more warming than predicted by CO2 only (curve A). not less.
KR says:
June 15, 2012 at 9:50 am
“Assuming that CO2 is the only active greenhouse gas is a common, but serious, error. CFC decreases were huge.”
Did you even look at the link you provided? Figure 2 http://www.esrl.noaa.gov/gmd/aggi/aggi_2011.fig2.png
shows: CFC-12 at about 525 ppt in 1998 and 515 ppt in 2011, and CFC-11 at 250 ppt in 1998 and 235 ppt in 2011.
What’s your definition of a huge decrease? And assuming you are right, the logical conclusion is that CFC’s were the problem, and that CO2 has little, if anything, to do with climate change. I’m happy with that result, time to end the CO2 BS once and for all. The science is settled.
I would like to speak out on behalf of the red herrings.
We are not a popular species, and we have had a bad press recently. In fact, we have been smoked
BUT….
when sea levels rise by ten feet, as jimbo has promised, in 20 years, we, the underpriviledged, kippers rouge, will have payback.