From Top Advisor To Australian Gov't Says Climate Change is a UN Conspiracy (slashdot.org) and Climate change a UN-led ruse, says Tony Abbott's business adviser Maurice Newman (The Sydney Morning Herald), Maurice Newman, the top business advisor to conservative Australian Prime Minister Tony Abbott:

"It's a well-kept secret, but 95 per cent of the climate models we are told prove the link between human CO₂ emissions and catastrophic global warming have been found, after nearly two decades of temperature stasis, to be in error ... This is not about facts or logic. It's about a new world order under the control of the UN."

This appears to have been sourced from a report reported in the conservative news source, Daily Caller:

Former NASA scientist Dr. Roy Spencer says that climate models used by government agencies to create policies “have failed miserably.” Spencer analyzed 90 climate models against surface temperature and satellite temperature data, and found that more than 95 percent of the models “have over-forecast the warming trend since 1979, whether we use their own surface temperature dataset (HadCRUT4), or our satellite dataset of lower tropospheric temperatures (UAH).”

Is there any basis for concluding that anywhere around 95% of climate models have been found to be in error in the way Spencer suggests?

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    I would suggest changing the title to something like "have 95% of climate models been found to be in error" instead of "Is climate change a UN conspiracy?" May 8, 2015 at 15:16
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    This question as is buckets together some disparate claims. It's possible that climate change is happening, that it's not a UN conspiracy, AND YET 95% of the models are in error. In fact, I think that's entirely reasonable. May 8, 2015 at 16:07
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    There is a big difference between "found to be in error" (which means "are not perfect") and giving invalid results. The fact that the speaker attributes the errors to a "New World Order" gives you some idea of the level of rationality being applied. May 8, 2015 at 16:21
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    This question is unanswerable without knowing what is meant by "in error". The complexity of weather patterns mean that no model is perfect, but that doesn't mean that broader predictions are incorrect.
    – KSmarts
    May 8, 2015 at 16:24
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    @Brian: The question of whether Newman had any evidence to support his claim is apparently "Yes. The report by Spencer." Rather than make that an answer, I've incorporated it into the question, so the more interesting issue can be addressed (is the report correct, under the definitions it provides), rather than bickering about what Newman might have meant. I hope that will get a more satisfactory answer for you.
    – Oddthinking
    May 8, 2015 at 17:22

1 Answer 1


The simple answer to this question is yes.

But the debate has been significantly obscured because the majority of contributors to it have chosen what appear to be poor ways of testing the claim with actual data (which is not, in principle, hard as the key data from models and observations are accessible).

Climate skeptics have used time series plots to compare models to observations but these are beset by bad choices of the normalisations for temperature anomalies and are a poor way to compare the underlying patterns due to the noisy nature of temperature time series.

See the claims Spencer makes here WattUpWithThat and a good critique of the errors here.

But there are ways of simplifying the comparison that don't suffer from these defects and these have been done by people who don't seem to have the same partisan desire to reach a particular conclusion.

This picture from a Nature article is the clearest analysis that avoids the various obfuscations possible when looking at noisy time series data:

nature chart

The choice made by these authors is to compare just the average extent of warming over a period rather than the noisy time series. This appears to avoid some of the choices that make the time series comparison so obfuscating and controversial. Their result seems to show that most models really do overestimate the actual amount of warming over recent years. In their words:

Recent observed global warming is significantly less than that simulated by climate models.

In somewhat more detail the authors talk about the statistics like this (my highlights):

The evidence, therefore, indicates that the current generation of climate models (when run as a group, with the CMIP5 prescribed forcings) do not reproduce the observed global warming over the past 20 years, or the slowdown in global warming over the past fifteen years. This interpretation is supported by statistical tests of the null hypothesis that the observed and model mean trends are equal, assuming that either: (1) the models are exchangeable with each other (that is, the ‘truth plus error’ view); or (2) the models are exchangeable with each other and with the observations (see Supplementary Information). Differences between observed and simulated 20-year trends have p values (Supplementary Information) that drop to close to zero by 1993–2012 under assumption (1) and to 0.04 under assumption (2) (Fig. 2c). Here we note that the smaller the p value is, the stronger the evidence against the null hypothesis. On this basis, the rarity of the 1993–2012 trend difference under assumption (1) is obvious. Under assumption (2), this implies that such an inconsistency is only expected to occur by chance once in 500 years, if 20-year periods are considered statistically independent. Similar results apply to trends for 1998–2012. In conclusion, we reject the null hypothesis that the observed and model mean trends are equal.

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    Your conclusion is unwarranted by your evidence: the evidence shows that there was less warming than the prediction, but still within 2.5 sigma, thus less so not significantly less so, at best barely significant.
    – Sklivvz
    May 9, 2015 at 13:07
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    @Sklivvz It isn't my conclusion but that of the nature paper. And your metric for significance is an extraordinarily high threshold. We are not comparing the noise in multiple observations for a single model with noise from observations (which I think is what your statistic implies).
    – matt_black
    May 9, 2015 at 13:20
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    @DikranMarsupial By the way, is Judith Curry right in saying there have been almost no published comparisons of models versus observations? I've struggled to find any doing a good job other than Fyfe et. al.
    – matt_black
    May 9, 2015 at 21:25
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    no, there are a series of projects (CMIP being only one of them, see e.g. www-pcmdi.llnl.gov/projects/model_intercomparison.php) that perform comparisons between models and observations. There are plenty diagrams in the IPCC reports comparing observations with model output. There are many climatologists that work on this, e.g. Ben Santer. Perhaps Prof. Curry is referring to some specific form of model-obs comparison?
    – user18604
    May 9, 2015 at 21:30
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    -1 Cherry picked "Commentary" article used to support the 6th most popular climate change myth (with links to the leading climate change denial blog no less). I.e., No, climate models aren’t exaggerating global warming.
    – Rusty
    May 11, 2015 at 6:23

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