Doh! Scientists Find “Significant Mismatches Between Modelled And Estimated SST Amplitudes”

There’s a new paper out called A model-data comparison of the Holocene global sea surface temperature evolution by G. Lohmann, M. Pfeiffer, T. Laepple, G. Leduc, and J.-H. Kim. Hat-tip: a reader.

This is an important study because scientists need a way to check the reliability of their models. If the models can recreate the past, then there’s a chance they can be used for the future.

We have about 150 years worth of reliable instrumental records that can be used to check models. Beyond that, scientists have had to reconstruct temperatures using proxy data. That’s the only way to check models that go way back. But we also know that using proxies as thermometers is not an exact science. Yet, with enough of them, you can get a pretty good idea of how climate behaved in the past. So it should be possible to use them to test models.

In the paper’s introduction we find:

Information beyond the instrumental record covering the last 5150 yr can be obtained mainly from two strategies: on the one hand by deriving from proxies which record past climate and environmental conditions, and on the other hand by simulating climate, using comprehensive models of the climate system under appropriate external forcing.”

Relying on models to tell us what the past climate was? Sounds rather dubious. So, according to the abstract, the authors compared the ocean temperature evolution of the Holocene as simulated by climate models and reconstructed from marine temperature proxies.

The proxy dataset comprised a global compilation of marine alkenone and Mg/Ca-derived sea surface temperature (SST) estimates. The authors write what they observed (emphasis added):

Independently of the choice of the climate model, we observe significant mismatches between modelled and estimated SST amplitudes in the trends for the last 6000 years. Alkenone-based SST records show a similar pattern as the simulated annual mean SSTs, but the simulated SST trends underestimate the alkenone-based SST trends by a factor of two to five. For Mg/Ca, no significant relationship between model simulations and proxy reconstructions can be detected.”

The authors later in the abstract add:

…when modeled temperature trends are set up to allow drastic shifts in the ecological behavior of planktonic organisms, they do not capture the full range of reconstructed SST trends. These findings challenge the quantitative comparability of climate model sensitivity and reconstructed temperature trends from proxy data.”

Most of us know that determining the “appropriate external forcings” (mentioned above) has been elusive in climate science, and has involved many dubious assumptions and downright hanky panky – all to make CO2 appear as the dominant driver.

Proxies will always be the superior way of determining how climate behaved in the past. Eventually models will be able to reproduce the past, but that will not mean they will be capable of predicting the future. One can use many different combinations of forcings in models to reproduce the past climate. But finding out which one was in fact correct, if any, will remain quite the challenge.

12 responses to “Doh! Scientists Find “Significant Mismatches Between Modelled And Estimated SST Amplitudes””

  1. thebiggreenlie

    Climate “modelling” is just a ridiculous exercise in software games for computers…………model all they want but introduce one major unexpected volcanic eruption into the equation and all the modelling in the world wouldn’t predict the true picture of climate for years!
    For so-called “climate experts” to suggest anything on their “modelling” is like saying they just discovered a major warming period coming with a Ouija Board!
    Also TC and Radio weather forecasters or as mass media like to tell people, their “meteorology experts” also depend on “modelling” for their forecasts and informed, scientific people know that one can’t predict a true picture of local weather past a 4 hour time span, yet these idiots give us 7 day+ forecasts.

  2. John F. Hultquist

    Intersting report. Thanks.
    The photo, while appropriate, has no context. Try this strange one:
    http://upload.wikimedia.org/wikipedia/commons/b/b3/Apple-pie_foraminifera_hg.jpg
    Apple pie decorated with foraminifera out of marzipan

    People do strange things.

  3. DirkH

    From the conclusions:
    “[the models] might have regional biases linked to the fact that the proxy data records used
    in this study are located in coastal areas which are challenging to simulate with global
    climate models”
    Challenging, well the understatement of the century, impossible is more like it. GCMs have rather large grid cells and cannot make them smaller because their statistical assumptions would break down, the assumption that MANY processes of the same kind happen inside one cell so that a statistical description suffices. This approach already breaks down for large convective fronts which can be much bigger than a grid cell.

    Coastal areas have arbitrarily fine detail; they are fractal in nature. The Alfred Wegener proxy researchers are wasting their lifes – what they do makes no sense. The modelers are no better. At best, they are tools for some international energy interests. Hope it satisfies them. It wouldn’t satisfy me.

  4. DirkH

    Another one of the EIKE videos from Nov 11 now posted on youtube, Chris Horner,
    a long one, but important – he describes the setting up of “safehouses” by the White House to help IPCC scientists communicate evading FOIA. Well, they won’t evade FOIA in the end, but it’s important to keep an eye on this; makes the IPCC an openly law-breaking organisation.
    http://www.youtube.com/watch?v=RXB_tmgcoak&feature=relmfu

    1. DirkH

      “safehouse” = web site on a neutral, non-gov server, with password protected login and forum software.

  5. DirkH

    Dr. Roy Spencer has identified a possible 0.5 deg C step change in UAH record in 1995 that happened when switching from one satellite to another. If this holds, current UAH temperatures show about 0.5 deg C TOO WARM.

    See second to last chart on this post:
    http://www.drroyspencer.com/2012/04/new-u-s-population-adjusted-temperature-dataset-pdat-1973-2012/

  6. Casper

    Sorry for Off-Topic, but it is important:

    France Calls For Retreat On EU Carbon Tax

    In a sign that Paris has little stomach for a fight over global warming, Francois Fillon, the Prime Minister, urged the European Union to retreat over plans to tax airlines for emitting greenhouse gases. His letter to Jose Manuel Barroso, the European Commission President, undermined the EU’s claims to be united in its drive to impose ecological virtue on the aviation industry. The plan to force airlines to buy pollution permits when flying in European airspace has been denounced as illegal by other capitals, notably Beijing, Delhi and Washington.(…)In his letter, written last month but made public yesterday, Mr Fillon said that 2000 jobs were under threat at Airbus and its suppliers because of the Chinese boycott.
    http://thegwpf.org/international-news/5391-france-calls-for-retreat-on-eu-carbon-tax.html

  7. C. Morissette

    Modeling IS an imperfect science… you would not find a single climate modeler who would tell you that what they are doing is exact. It’s strange how uneducated people cannot grasp the value of an estimate. Most of paleo science is based on assumption and estimation, take it as you will.

    However, there are MANY proxy-based reconstructions that will show that CO2 is indeed “the culprit”;it tends to be the grossly rich energy sector people who spend millions upon millions of dollars to make it appear as if this fact is not universally accepted in the science world. This is accepted as a scientific fact.