Norwegian Climate Professor: Hansen’s Projection Off By 150%…Regrettable That Politicians Still View It As Reliable

At their Die kalte Sonne website, Professor Fritz Vahrenholt and Dr. Sebastian Lüning present a guest post by Prof. Jan-Erik Solheim, who comments on the huge divergence between Hansen’s 1988 forecast and actual observations. I’ve translated his guest post in English:

What ever became of James Hansen’s 1988 temperature forecast? Time for an evaluation
by Prof. Jan-Erik Solheim

One of the most important publications on “dangerous man-made climate change” is one by James Hansen and his colleagues in the year 1988 which appeared in the Journal of Geophysical Research. The title of the publication: Global Climate Changes as Forecast by Goddard Institute for Space Studies Three-Dimensional Model.

Figure 1: Temperature prognosis by the Hansen Group from 1988. The different scenarios assume 1.5% CO2 increase (blue), fixed CO2 emissions (green) and stopped CO2 emissions (red). In reality CO2 emissions have increased about 2.5% per year, which would be more than depicted the the blue curve scenario. The black curve is the actual temperature (smoothed 5-year mean). The Hansen-Model overestimated the temperature by 1,9°C and is thus a full 150% off. Graph supplemented as to Hansen et al. (1988).

In this publication Hansen and his colleagues present the GISS Model II, which simulates climate changes resulting from concentration changes in atmospheric trace gases and airborne aerosols. Here the scientists illustrate three scenarios:

–A: Increase of CO2 emissions of 1.5% per year
–B: fixed increase CO2 emissions after the year 2000
–C: No increase in CO2 emissions after the year 2000

CO2 emissions have increased at rate of about 2.5% since the year 2000 and so according to Hansen’s paper, we would expect a temperature increase greater than the Model A scenario. Figure 1 shows all three of Hansen’s scenarios as well as the real measured global temperature.

The arrow extending beyond Scenario A shows the temperature value that should have been predicted by the Hansen Team based a CO2 increase of 2.5%. According to Hansen’s projection, the temperature should have increased 1.5°C when compared to the 1970s level. In truth the temperature rose only 0.6°C.

It is clearly visible that the temperature forecast modelled by the Hansen Group is off by about 150%. It is truly regrettable that precisely this modelling is still being viewed as a reliable forecast by our politicians.


Jan-Erik Solheim is professor emeritus University of Oslo Institute of Theoretical Astrophysics, an active member of the International Astronomical Union, and authored a number papers on climate change.

UPDATE: Steve Goddard adds some background info at his site


20 responses to “Norwegian Climate Professor: Hansen’s Projection Off By 15020…Regrettable That Politicians Still View It As Reliable”

  1. Edward.

    All the evidence points to CO2 rising as the world warms, not the other way around.
    Even, if you do believe that CO2 is causing runaway warming, presently, there does seem to be a rather a big problem. Could it be? – Is it that – all the predictions of thermogeddon were just like the IPCC ‘hotspots’ – merely idle and erroneous speculation?


    Climate models, particularly those of Hansen’s GISS and indeed those attributed to the IPCC are not worth spit but boy oh boy are we paying for them.
    Carbon emissions taxes on business and manufacturing costs affects everyone but particularly countries such as Denmark, Germany and Britain.

    In the USA, where Hansen ‘divines his portents’, why though does no one question this outrageous waste of taxpayers dollars?

    “Since 1989 the US government has spent almost $100 billion on climate studies, modeling, prediction, regulations and more. In the end, the best models developed so far do 2 – 3 X worse than chance alone! As real world temperatures continue to diverge wildly from climate model projections, US taxpayers are starting to wonder where there money is going.”

    It would be interesting, to see the accounts of the PIK , or how much is wasted on inane models, bogus research and climate advocacy in the UK.

    Soon though, it will all be over forever, the world is moving on – it will begin in Socialist Europe and the tremors will be felt world wide, there will be no more taxpayer funded research into CAGW.

    1. Illidanek

      You’ve said it all, Edward. Couldn’t agree more

    2. Mindert Eiting

      I’ve just read that IPCC scientists are pleading for immunity from criminal prosecutions. That may be the next stage.

  2. Marianita

    It really is time these guys be taken to court for fraud and/or misrepresentation

  3. Dave Waller

    Before I use this in argument, what data set was used for the observations? Throwing Hansen’s own analysis and forecast at the True Believers is an exceptionally powerful argument, however I know the first thing my friends will do is claim the observations are suspect. Of course, if I can then respond that they’re from GISS or HadCRUT4 or something like that, I’m back in the catbird’s seat.

    1. DirkH

      Steve Goddard has made similar comparisons. Search his blog for “1988”, you find many hits; here is a good one where he compares Hansen’s 1988 projection with GISS temps:

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  7. lemiere jacques

    well i am not sure the absolute value is relevant, but the slope .

  8. Ron Greer

    I totally agree with Dave Waller. The actual data set for the actual temperature data has got to be beyond quibble in reliability and authenticity. We cannot afford to use barbless hooks on this fish, we need bite proof wire trace and we must not operate a catch and release policy.

  9. GregO

    Hansen is mad. Here a former kook who appears to be seeing the light:

    1. DirkH

      His point about Germany is good: “but they have this fatal flaw that they always fall for an ideologue” but OTOH every British expat I worked with said that.

      His current pro-fracking stance impresses me not; he regularly goes against the mainstream, I think to sell more books.

      Here, he, maybe with some misrepresentation help by the Guardian, he misrepresents skeptics as idiots. We don’t know what he really said or meant as the Guardian had his hands in the information transfer but it doesn’t describe me and makes no sense. Greens have been around since Der Wandervogel and longer. What is he talking about?

      “He displays equal disdain for those who do not accept science on climate change: “They’ve got their own religion. They believe that the world was right before these damn people [the greens] came along and want to go back to where we were 20 years ago. That’s also silly in its own way.””

  10. Peter Mizla

    Lets see how fast the arctic melts this summer. Lets see how warm 2013 is likely to become. I would love to return here in a year or two and see the same group of nobobdies debating a straw figure.

    1. Ed Caryl
  11. Peter Mizla

    The ancient confusian saying, “It hasn’t warmed since 1998”, has been well debunked by now, but it keeps getting bunked. Today’s release of preliminary global temperature data for May 2012 provides yet another nail in the proverbial coffin, however. With the latest May land and ocean average temperature taking second place behind 2010 for warmest on record, May 1998 has been pushed down to third place. And what about the other 12 years this century, beginning with 2000? The CapitalClimate chart from National Climatic Data Center data shows that every single one of these years is also in the top 14 warmest for the month of May.

    1. DirkH

      I’m confident that 1998 will continue to cool significantly in the data sets handled by NCDC and GISS.

    2. DirkH

      While you are talking about MAY temperatures, Paul Homewood has taken a more holistic view… looking at entire YEARS (wew!)

      Even in a warmist data set years after 1998 don’t look so hot…

  12. Pierre Gosselin: Norwegian Climate Professor: Hansen’s Projection Off By 150%…Regrettable That Politicians Still View It As Reliable |

    […] ever became of James Hansen’s 1988 temperature forecast? Time for an evaluation” here (No Tricks Zone) Share this:PrintEmailMoreStumbleUponTwitterFacebookDiggRedditLike this:LikeBe the […]

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