1988 : Hansen Forecast Fail


The red line shows the GISS trend since 1960. Temperatures are running below Scenario C, which assumes that global warming stopped eleven years ago.

“scenario C assumes a rapid curtailment of trace gas emissions such that the net climate forcing ceases to increase after the year 2000.”


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67 Responses to 1988 : Hansen Forecast Fail

  1. Kelathos says:

    His forecast is perfect if the net forcing ceased to increase, or more likely, never existed in the first place.

    • glacierman says:

      You are correct, this is very good evidence that Hansen and others assumptions about the direction and magnitude of feedbacks have been significantly over estimated.

  2. Lance says:

    Senario C is a success! Congrats to all peoples of the earth for cutting your emissions to zero!
    /sarc off…

    • K says:

      Don’t laugh. When “Population Bomb” author Paul Ehrlich was confronted with the utter fail of his predictions, his response was that his book had prevented it.

      Stand bye for some similar semi-plausible BS coming from the warmistas.

  3. Latitude says:

    can I stop holding my breath now…………….

  4. Sundance says:

    I’m jealous of Hansen. I wish I had a job where I could be wrong by a factor of 135% and still keep my job. Only in the religion of climate can you screw up that much and still be adored by your followers.

    • Al Gored says:

      No. Bernanke and Geithner and all sorts of Wall Street Hansens are still employed. So are most of the people who flogged the Iraqi WMD scam.

      Not surprisingly, the UK’s cheerful poodle Bliar is now a ‘highly paid climate change consultant.’

  5. Eric Anderson says:

    Thanks for this graph. Helpful to see the overlay — I still hear weak attempts to justify Hansen’s 1988 forecasts from time to time.

  6. Brian H says:

    Re: (Feb 22 20:09),
    Oh, stop with this “significantly over-estimated” waffling. The correct term is “concocted” or any of its more full-blooded synonyms.

  7. No, no, James Hansen is not wrong. They tell us he is the top climatologist in the world. How could he be wrong? It’s just that he’s so beyond us we don’t understand him. He meant something else. Also, Manhattan really is covered in water as we speak—just that it’s in the form of snow. See? He’s right.

    So those graphs are right……….. Naaaah!

    What he really meant was he used a graph to show everyone how much he was going to adjust the data.

  8. Jimbo says:

    You people should learn to never ever believe your own lying eyes. /sarc

  9. The lesson for the Left will be to never make apocalyptic claims that include specific metrics. In fact, they’ve already started laying the groundwork for this new strategy by failing to teach an entire generation of kids how to do basic math.

    “Because the Only Good Progressive is a Failed Progressive”

  10. Hainer says:

    Hansen’s forecast is in support of a myth. How can it not be wrong.

  11. Alcheson says:

    Hey guys… I know this isn’t directly related to this post but I’ve been working on a powerpoint global warming/ocean acidification presentation (from a skeptics viewpoint of course). I’ve got the AGW part nailed down but having some problems with the ocean acidification. I can pretty much show that is not going to be a problem. However, in all my research, I can’t find any recent ocean pH data no matter how hard I search the net. Even Wikipedia’s current ocean pH number comes from 2005. All the actual data you can find shows no measurable pH change since 2003. Found one set that goes to 2008 but pH was flat since 2002. Makes me wonder if the people who collect pH are hiding recent data from the last 5 years because the pH is either flat or starting to go back up?

  12. Dr. Killpatient says:

    I wonder if Hansen would be kind enough to let me in on who he’s picking for next year’s Superbowl…

  13. Sparks says:

    Hey that chart’s wrong!

  14. Jack Savage says:

    What has changed is…..instead of the temperature going up as much as Hansen projected, the actual temperature change has become more dangerous! A trend that was once regarded as an indication of natural variation is now a dangerous threat….. particularly as it is going to shoot up (any moment, you wait!) once a “tipping point” is reached.
    Why can you deniers not understand this? The science has moved on!

  15. Doug Proctor says:

    This is from the Jan. 11/2011 RealClimate post, in which GS vigorously defended Hansen’s predictions. Several e-mails between myself, a blogger “RC” and GS ensued. GS contended that I/RC were wrong in the Scenario C correlation, on the basis (I found it impossible to understand) that 1) “C”, was a prediction based on non-real elements, i.e. that post-2000 all emissions stopped, and 2) that “C”, based on non-real input, was not “useful”. I complained somewhat rudely: “useful” was too obvious a term for circular thinking, and the fact that non-real input lead to the best correlation should have (in my opinion) made one uncomfortable that ANY of the scenarios (esp. “B”) reflected real-world connections between conditions and global temperatures.

    Check out the arguments if you wish. The defense of “B” and dismissal of “C” struck me as a “denial” position (a comment that Dr. Spencer correctly recognized as unhelpful, though psychologically that is what you are in when you cannot accept truths that strongly challenge your self-image).

    The Jan. 11/2011 RealClimate post discussed here is the most obvious example of the circular thinking of the warmist creed: the evidence against global warming is flawed as global warming is proved elsewhere by other evidence, so we need only to offer the evidence supporting global warming related to this aspect.

  16. Doug Proctor says:

    Sorry: the original post is 21 January: 2011http://www.realclimate.org/index.php/archives/2011/01/2010-updates-to-model-data-comparisons/

    335 comments, mostly about details.

    Also in question: Lyman et al (2010) oceanic heat content vs SST records, including ARGO. The disconnect interpreted as heat “below measurements” is another argument from ignorance. Other possiblilty is that the concepts are flawed, so all the calculations are irrelevant.


  17. sacculina says:

    I’m pretty sure you must realise that the selection of a single linear trend proves absolutely nothing. Do yourselves a favour and go back to woodfortress, and plot linear trends in temperature from more or less any year other than 1960 to the present day. You will find the slope moves around, as you’d expect, but in almost all cases the slope increases, compared to the one Goddard uses – I’m sure he understands this too.
    Basic schoolboy error – or attempt to deceive? You decide.

      • sacculina says:

        Yeah – I’ve seen that graph many times over, thanks.
        Regarding the absence of warming in the past decade, do you have anything to say about the decline in total solar irradiance during the same period, which could easily explain the lower than expected warming due to CO2 forcing, and the fact that TSI is about to start returning to its cyclical upswing? Worrying, no?

      • sacculina says:

        Oh dear, I’m boring you.
        Sad reality is though, that rather a lot of people seem to use the stuff posted on this site as Gospel. It’s an important consideration.

      • sacculina says:

        I wish I were trying ‘to be funny’ Mr Goddard. Your stuff crops up all over the place as support for the case against AGW – it is very popular. I am all for debating the issue, and seeking alternative explanations, but using scientific dishonesty and bias is not really part of a fair and sensible debate is it?
        Anyway, I’ll leave it with you to amend (or not) the above – perhaps by adding a couple of other trend lines to express some of the uncertainty.

      • sacculina says:

        Mr Goddard, as you know, there is no value in taking a single point estimate to support your argument. However you slice them, the three temperature series show a upward trend quite a bit higher than the one you are trying to peddle above. Again here are the data from the instrumental records.
        Please acknowledge that you are being highly selective in your choice of data above, and we can all move on.

        • Please acknowledge that you are arguing a straw man. Temperatures have not risen as predicted by any scenario, much less the relevant one – scenario A

      • suyts says:

        “Your stuff crops up all over the place as support for the case against AGW – it is very popular.”

        Wow, congrats again Steve.

        “do you have anything to say about the decline in total solar irradiance during the same period, which could easily explain the lower than expected warming due to CO2 forcing, and the fact that TSI is about to start returning to its cyclical upswing?”

        Beautiful, lack of solar irradiation explains lower temps, but CO2 causes the earth to warm? Wonderful, we have two different primary switches, one for lowering and another for raising.

        As to the concern about Steve’s selection, apparently some prefer flat lines…….


        Yeh, shows a lot of hotting up. So, we’ve now 1 land and 1 sat that shows slight cooling to no warming. That leaves 1 land (GISS) and 1 sat, (UAH). So, what now, are we to argue which satellites hold more validity? Or are we going to argue the validity of Hansen’s ever changing historical data?

        sacculina, be sure to hang around. You’re fun!

      • sacculina says:

        suyts – I think my second post (above) went over your head. Hauling out this same chart on woodfortrees reinforces my point, it doesn’t dispute it (what do you think would have happened to temperature if solar irradiance had stayed the same?). As for the original premise of the article (the single linear regression line), I shall put together a nice little graphic which acknowledges the uncertainty around this slope – based on the actual temperature records – I was hoping Goddard would have acknowledged it, but it looks like i’ll have to do it myself.

      • suyts says:

        lol, no it didn’t go over my head, my woodfor chart was a response to yours.

        sacculina, I’ve seen several theories as to the sun’s variances and the possible effects it has on the earth. I’ve seen everything from the sun is basically a constant to it varies wildly and has significant impacts on the earth’s temp. I don’t believe anyone is in a position to know. Perhaps Leif or Tallbloke would be more fun to argue with. In the mean time we can wait for the Glory mission to start bringing us back some data.

        Personally, I think the sun effects the earth’s temps greatly. I also think we’re not measuring something properly. What exactly, IDK. I also believe some equilibrium seeking mechanisms engage here on earth. Again, weighting and quantifying, I don’t believe anyone is in a position to make statements with any certitude.

        Here’s what I don’t know. CO2 and the sun’s variances can’t both be the primary forcing of the earth’s temp.

        But, now let’s get back to the topic at hand…… I breathlessly await your graphic that validates Hansen’s prediction.

      • sacculina says:

        Robb, my charting of the data broadly concurs with yours. The linear trend from 1985 does indeed increase the slope, which returns us nicely to the orginal point made – that plotting a linear regression from 1960 to 2011 (and simply letting the same slope run through to the present day) is wrongheaded and misleading, when we have data from 1985 to 2010. Mr Goddard, why did you choose not to plot the linear trend from 1985? Hansen was still a little off, but the honest picture – though correct – would perhaps not quite as dramatic?

        GISS land sea data
        Raw difference
        0.64 1960 to 2010
        0.59 1985 to 2010

        Rolling 5 year mean difference
        0.548 1960 to 2010
        0.448 1985 to 2010

        Rolling 10 year mean difference
        0.552 1960 to 2010
        0.454 1985 to 2010

    • suyts says:

      I’m pretty sure you realize your little exercise proves absolutely nothing while Goddard’s line does indeed prove something. Hansen was wrong.

      • sacculina says:

        My ‘little exercise’ shows that the whole premise of this piece is based on a SINGLE linear regression line. It becomes particularly relevant when you examine more or less any other slope other than just the one from 1960 to 2011. It’s called cherry picking to suit a pre-ordained conclusion

      • suyts says:

        sacculina, I can’t speak for Steven, but I’m pretty sure the whole “premise of this piece” was to show the inaccuracies and uncertainties of climate science. Steven didn’t pick the time frame, Hansen did. Steven simply plotted reality into Hansen’s prognostications. I know this is a tricky concept for alarmists, but its fairly useful for people known as realists.

    • Paul H says:

      Hansen was still ridiculously wrong though wasn’t he?

      • sacculina says:

        Continuing your logic, and plotting the change since the end of the instrumental record (looks like about 1985 in the paper), Hansen actually looks pretty conservative in his original estimate. Please do your readers a favour Stephen, and overlay this on your graph above, it’s likely a fairer representation.

      • Robb says:


        I did what you asked Steve to do. Only I overlaid GISTEMP which is more closely tied to Hansen & shows a steeper temperature rise)

        Look at these composites of Hansen’s predictions overlaid with the GISTEMP record for the corresponding time period 1960-2010 adjusted for scale.

        Here & Here

        You’ll clearly see that the records match the observed data (up to Hansen’s endpoint. You’ll also clearly see that we are currently BELOW his predicted “Scenario C” (which the temperature record follows pretty closely) which accounted for “a rapid curtailment of trace gas emissions such that the net climate forcing ceases to increase after the year 2000.

        There are only two conclusions you can draw from this.

        1. We unknowingly curtailed trace gas emissions rapidly ceasing climate forcing increases by 2000.


        2. Hansen unknowingly invalidated the theory of AGW by showing that even with CO2 increasing by approx. 45ppmv (Hansen stated that CO2 was 345ppmv in the paper), the atmosphere reacts as if trace gas emissions stopped.

        Do you really want to stand by your statement of “,i>Hansen actually looks pretty conservative in his original estimate.“?


      • Robb says:

        Yes, I know. Sacculina’s plot used HADCRUT I was just pointing out to him I used a different dataset than he did.

        Also, did you look at my composite? Based on observation temps, Hansen’s forcing theory is basically invalidated by his own paper.

      • sacculina says:

        Thank you Robb – I will check this over tonight. If you are correct, I will of course acknowledge this.

      • sacculina says:

        comment above – attached to the wrong thread.

      • Robb says:


        What is your point exactly? That Steve attempted to mislead by showing a trend line of Hansen’s entire dataset? Or is it that the rate of warming is greater than what he illustrated?

        Of course the slope is different with different start years. The mid 80’s we’re cooler than the early 60s. So depending on where you start the rate will be different.

        The point (Steve please correct me if I’m wrong) of the trend line graphic that Steve posted was to show what he used plot Hansen’s model run outcomes vs observed temps.

        Hansen’s model runs we’re programed to forecast particular scenarios from 1960 to 2019 based on his GHG forcing/feedback theory. Look at how the scenario plots overlap the observed data. Since the model runs started in 1960 why do you have a problem with Steve using temp data starting in 1960 unless your posts are an attempt to distract from the point that Hansen’s “Scenarios” were utter garbage when put up against observed data?

        So, Continuing YOUR logic, if temps reached their current levels in say 1991 and stayed constant until today and the trend line was flat from 1985-present, what would that mean?

        I’m all ears.

      • sacculina says:

        My point Robb, is very straightforward. The correct slope to use is the one starting in 1985, as that is the end of the observed data set in Hansen’s paper. Bearing in mind that the increase in temperature was less between 1960 and 1985 than it was between 1985 and 2010, using the 1960 to 2010 is not only misleading, it is methodologically wrong. The linear trend line on the graph above should start at 1985. As I said – simple.
        If you makes you and Goddard feel better, Hansen’s predictions on this single model were still not correct of course – but you could cut him some slack (it was 25 years ago); meanwhile global temperatures are still increasing.

      • suyts says:

        sacculina, all of this for that?

        “The linear trend line on the graph above should start at 1985. ” and “If you makes you and Goddard feel better, Hansen’s predictions on this single model were still not correct of course…”
        Get beleaguered by minutia much? You think there may have been a slightly easier (and much less time consuming) way to express that?

        Yes it was 25 years ago, but, some of us think it is important to revisit some of the impetus of the current climate hysteria.

        Meanwhile, there are many other fun things that have been and are to be discussed……….stick around!

      • Robb says:


        You don’t read much of the literature do you?

        Yes the model runs we’re done 25 years ago, but Hansen revisited the issue in a paper in 2007. (Reference here) in which he writes (and I quote): “Indeed, moderate overestimate of global warming is likely because the sensitivity of the model used (12), 4.2°C for doubled CO2, is larger than our current estimate for actual climate sensitivity, which is 3°+- 1°C for doubledCO2, based mainly on paleoclimate data (17).
        More complete analyses should include other climate forcings and cover longer periods. Nevertheless, it is apparent that the first transient climate simulations (12) proved to be quite accurate

        (by the way, doesn’t 3°C +1°C= the 4°C he just said overestimated temps in his models? The circular spin this guy puts on things is amazing!)

        19 years later (just 4 years ago if you’re following along at home) he thinks they were “quite accurate”?

        We’re still emitting at a Scenario A level (predicted 1.1°C warming).

        But we haven’t experienced Scenario C (predicted .7°C) warming.
        Observations show we’re .6°C above baseline.

        His predictions we’re off by almost 100%! Do you grasp the significance of being off by an order of magnitude and then saying you were “quite accurate”?

        No, I for one will not cut him some slack.

        And one last time I will attempt to explain that your “trend” point is a non-point.

        HERE is the same image as before with both trend lines. The result is the same. Hansen is wrong by an order of magnitude.

        I think what you’re upset about is the image Steve posted of just the trend line from wood for trees. Again, that was just to show what he was plotting over the Hansen chart, not to insinuate anything about the rate of warming.

        Also, Hansen’s data did not end in 1985. Hansen did not use ANY data. The paper was a result of the output of model runs simulating different levels of forcings. The “Data” you keep referring to was observational temps plotted over his model output to show how well his model backcast temperatures. It’s exactly what I did in my first graphic. I plotted observed temps over his model runs. I just have more data then he did 25 years later.

        So Steve using his entire model generated time series to overlay on his model output is neither “misleading” nor “methodologically wrong”. It’s actually inconsequential to the discussion.

      • Robb says:

        Srry, I messed up th link on the Hansen et. al 2007 paper.

        it’s here

      • Robb says:

        Sorry #2 I used the phase “order of magnitude” incorrectly in my last post. I just get so worked up when people don’t see what is right in front of them. That said, Hansen was still wrong by a lot 🙂

      • sacculina says:

        Thank you for your considered reply Robb. It seems we essentially concur that the choice of start point for the linear trend line above is incorrect. Yes, 1985 doesn’t make a huge difference, but it does make a difference, and I am not sure why Goddard did not use that (he can still change it of course). The method is important, particularly if you are trying to tell a particular story.

      • sacculina says:

        I pleased to see you were not being deliberately misleading Mr Goddard, you simply still seem to not understand your basic methodological flaw. Somehow that gives me solace.
        I’m sure we’ll chat again.

      • Robb says:


        I was going to ignore your post because I now realize all you are attempting to do is distract from the fact that Hansen’s models are sensationally wrong.

        But in you last response you said “It seems we essentially concur that the choice of start point for the linear trend line above is incorrect“.

        For the record we do not agree. What I said is that the start point is UNIMPORTANT. You do realize that the “linear trend” has nothing to do with actual temperature. You must know that where your little trend line ends is not at the actual temperature. You have to understand that Hansen’s model results did not include and “data that ended in 1985”. From this i must infer that you are being consciously deceitful. Because if you’re not, you must have the worst reading comprehension skills in recorded history. That said I will break this down one last time. I’ll go slow and use small words in hope that you get it this time.

        Hansen produced 3 model runs.

        They were programed to simulate temperature from 1960-2019 under 3 different forcing scenarios.

        They were all very, very wrong.

        Four years ago he still claimed they were “quite accurate”.

        You can remove the “data” overlay from his chart and it would not change the results. It was just there for illustration.

        It doesn’t matter if you draw a trend line from 1960 or 1985, or B.C. 800.

        That pretty much sums it up.

        The methodology Steve used was perfectly sound in start date choice, as Hansen’s temperature “trends” (for lack of a better word) were predicted from 1960, not 1985.

        Lastly, please take note that Steve did Hansen’s ridiculously incorrect predictions a favor by using a trend line as opposed to actual temperature. If you go back to wood for trees and run the linear trend & the actual temperature data, you’ll see the measured temps are actually lower than where the trend line ends. You see, the linear trend is just a projection of the direction and rate of change. It’s not actually the temperature!

        But again, I’m guessing you knows all this. If you don’t, I feel sorry for you and hope you will take the time to learn.

        If you do, I’m sure you parents are very proud of how you spend your free time.

      • sacculina says:

        The instrumental (observed) data ended in 1985, so again, I repeat, if you are going to use a simple linear regression it should be from 1985 to the present, not 1960 to the present.
        This is the only reasonable approach, particularly when the overall trend is non-linear, which it clearly is. Yes, Hansen was still basically wrong.

  18. Doug Proctor says:

    Y’all might find this a remarkable comment from GS/RealClimate regarding CAGW:

    Comment DP: “… Rather than support the CAGW, this post [support of 1988 Hansen] seems to support global warming of a moderate level, but not of a disasterous level …”

    [Response: ‘C’AGW is not any actual scientific hypothesis, theory or result. To my knowledge it has never appeared in the text of any IPCC, NAS or Royal Society report. It only exists in contrarian blogs when people want to argue against some strawman. Since I don’t know what it is, nor have I ever written about it or seen it honestly described, I have no idea whether what I wrote supports it or not. If you would like to know what the scientific projections are and why people are concerned about ‘business-as-usual’, please see any of the reports I mentioned above (or read this). The updates here all support that concern. – gavin]

    Comment by Doug Proctor — 22 Jan 2011 @ 1:36 PM

    CAGW: GS doesn’t know what it is, it exists in only “contrarian blogs”, yet the whole Hansen-Gore-GS meme is the coming world disaster. Without CAGW, AGW is just GW. Scenario A is not CAGW? Wow. So why are we looking at Cap-n-Trade?

    • suyts says:

      Doug, it is the escape hatch. The duck and dodge. They cannot and will not attempt to define CAGW/CC/or what ever term it is today, beyond very vague terms. It is undefined, therefore, unfalsifiable. Also, because it is undefined, they can make vague but contradictory statements and always be correct. For example, the recent snows this winter caused a number of scientists to state we would expect that in a warmer climate. But, they are definitive. Alternately, we saw other groups of scientists go on with their dire predictions of droughts. Again, not very definitive. So, while not being definitive, they will definitely be correct on one or the other prediction and likely both! Of course, the fact that throughout recorded history man has had simultaneously floods and droughts in different regions of the world seems to escape most muddled thinkers.

      • Brian H says:

        There are further weasel-words there, too: ” in the text of any IPCC, NAS or Royal Society report.” But (IIRC, I’m not going to try to chase it down just now) the term or its synonym has been used in public presentations by spokespersons. Certainly it wouldn’t be hard to extract such from Hansen’s rants.

  19. Robb says:

    Amazing how much Hansen’s “Scenario C” looks like Syun-Ichi Akasofu’s “Natural Recovery from The Little Ice Age” (PDF link to paper here (see chart on pg. 7 for comparison to Hansen’s prediction.)

    You should check out the research they’re doing at the IARC about Multidecadal variability (MDV) in the Arctic and North Atlantic Climate System as well. Great stuff!

    But be careful though, they’re funded by denialists like NOAA, the National Science Foundation and the Office of Naval Research. /sarc

  20. Gator says:

    Somewhere in North America, there is a crazed and desperate balding NASA emlpoyee ripping more rural thermometers out of the GHCN.

  21. justasimplepatriot says:

    And what would the GISS line look like if the reporting stations were not plagued by UHI and other siting biases?

  22. MostlyHarmless says:

    For sacculina:

    Lets’s not look at a linear trend, but look at the data instead:
    Gavin says “As stated last year, the Scenario B in that paper is running a little high compared with the actual forcings growth (by about 10%)”, which for 2010 is more than 0.4ºC higher. So 0.4ºC is “a little high”? Since 2005, temps have tracked lower than scenario C, and overlain it or been below it since 2000.

    Scenario C was created as a baseline (no increased forcing from 2000) to track the other two scenarios, yet actual temps rarely rise above it. That’s a qualified success in forecasting?

  23. Gator says:

    President Obama’s regulatory czar, Cass Sunstein, argued the U.S. government should ban “conspiracy theorizing.” Among the beliefs Sunstein would ban is advocating that the theory of global warming is a deliberate fraud.

    [W]e suggest a distinctive tactic for breaking up the hard core of extremists who supply conspiracy theories: cognitive infiltration of extremist groups, whereby government agents or their allies (acting either virtually or in real space, and either openly or anonymously) will undermine the crippled epistemology of believers by planting doubts about the theories and stylized facts that circulate within such groups, thereby introducing beneficial cognitive diversity.

  24. John Harmon says:

    Not well enough educated to argue the technical aspects but even a B.A. in psychology from 1971 allows some conclusions. CO2 has almost nothing to do with raising earth’s temperature. Vostok and Greenland show CO2 above 7000 yet the world cooled enough for Ice Ages. Variation is normal. The Romans in A.D.70 used Tamarind trees in the attack on Masada that could only have groen in a climate much wetter than today. And warmer. Sea shells from Iceland show much higher water temps 1000 years ago. I conclude that Pres. Obama and Hansen are misusing “unprecedented”. In Ecclesiastes it says all that has been will be and all that will be has been. Looks like the Progressives would beefit from reading the Bible and letting a few crises go to waste.

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