Models of reality

NZCSC chairman Barry Brill has suggested to Environment Waikato that its Regional Policy Statement (RPS) should not be influenced by the climate change ‘Guidance Manuals’ (here and here) issued by the Ministry for the Environment in early 2008. Like the IPCC’s Fourth Assessment Report (4AR), their recommendations have been overtaken by recent scientific papers and data. His submission notes that modelled projections of 21st century warming rely upon two components – emission volumes and climate sensitivity. Here is his comment regarding Climate Sensitivity.

CLIMATE SENSITIVITY (Model Uncertainties)


The 17 models used for the 4AR produced a 2100 temperature range of 1.8°C – 4.4°C. Note at page 122 of the Manual, “this arises from taking the best estimate temperature change, and subtracting 40% to get the low end, and adding 60% to get the high end of the range”. The “most likely” temperature trend is 2.7C per century.

The key driver of models is net climate sensitivity. It is well accepted that doubling pre-industrial CO2 levels (to 560ppm) will cause a direct temperature increase of approximately 1°C. This initial warming then causes a plethora of positive and negative feedbacks which eventually produce a ‘net’ effect somewhere in the range of 0.4°C to 4.0°C. Clouds (and atmospheric water vapour) are the major confounding element, having both positive and negative impacts depending upon height, type, shape, etc.

None of the models have been verified or validated in any way. The IPCC requires, however, that all models are reasonably accurate in “hind-casting” actual 20th century temperatures.

Modelling is as much an art as it is a science, and the IPCC does not contend that any one of the 17 models is correct. There is no statistical rule that accuracy can be achieved by averaging any number of inaccurate values. However, as the outputs represent the opinions of highly experienced teams of climate researchers, the IPCC regards the mean of those outputs as persuasive. While accepting that view, this submission notes the very high levels of uncertainty.

In particular, 4AR considers that the feedback effects of clouds and water vapour are highly uncertain.


The IPCC Models consistently display a “hotspot” in the upper tropical troposphere as a “fingerprint” of greenhouse gas forcing. Despite persistent efforts with weather balloons and satellites (especially during the past five years) scientists have not been able to verify the existence of the characteristic hotspot.

Reifen & Toumi (2009) examine the proposal that a model which has successfully hind-cast past climate can be relied upon to predict future climate. The researchers found “no evidence of future prediction skill delivered by past performance-based model selection” noting that “there seems to be little persistence in relative model skill”. They speculated that the cause of this behaviour was the fact that climate feedback strengths are not stationary – “models that respond accurately in one period are likely to have the correct feedback strength at that time” but that “the feedback strength enforcing is not stationary, favouring no particular model or groups of models consistently.”

During the past two years, six peer-reviewed papers have substantially affected the calculation of net climate sensitivity:

(i) Solomon et al (2010) found that the warming observed in the 1980 – 2000 period was partly attributable to an unexplained 10% increase in water vapour in the lower stratosphere. The paper estimated that 30% of the warming recorded during 1990 – 2000 was the result of this phenomenon. Stratospheric water vapour levels returned to normal in 2001 and subsequently, causing 21st century temperatures (to date) to be 25% lower than originally projected.

(ii) Schmittmer et al (2011) applied extensive historic reconstructions to establish that the range of net climate sensitivity is 1.7°C to 2.6°C, with 2.3° being most likely. The research team found “implausible” the “fat tail” of high levels reported in the 4AR, finding only “vanishing probabilities” for a value greater than 3.2°C. This conclusion supported an earlier paper by Annan & Hargreaves (2009) which proposed an upper range limit of 4.0°C.

(iii) Lindzen & Choi (2011) observed that outgoing radiation measurements (satellites 1985-2008) disclosed net negative feedback – implying that “the models are exaggerating climate sensitivity.” The net climate sensitivity was found to be 0.7°C (range 0.5°C – 1.3°C) at a 99% confidence level.

(iv) Spencer & Braswell (2011) found that the sensitivity and cloud cover assumed by models departed substantially from the earth’s measured heat-loss during 2000-10.

(v) Douglass & Knox (2012) graph the recorded changes in ocean heat noting the heat loss of -0.03 W/m2 during 2001-9. The paper records climate shifts in 2002 and 2009, criticising the calculation of a trend across a climate shift.

(vi) Davies & Malloy (2012) of the University of Auckland reported that the average height of clouds declined by 44m/decade during the period 2000 – 2010. This decline denotes a major reduction in the global temperature trend at the rate of approximately 1.0°C/century, and indicates that net cloud feedbacks must have been negative so far this century.

The updated science puts the theoretical net climate sensitivity at 2.3°C based on paleoclimatic studies (Schmittner), or 2.0°C based on physics (Solomon). The actual observed science suggests a total level (i.e. Human Warming + Natural Variability) of 0.7°C late last century (Lindzen) and about 0.0°C to date this century (Davies).


The cumulative effect of these papers suggests that the IPCC projection of Human Warming at 2.7C/century should be adjusted down to approximately 1.0°C/century. This is about the same level as would arise from an unadjusted projection of the 20th century trend.

Professor Michael Kelly of Cambridge University remarked on 29 February in a letter to The Times:

“The interpretation of the observational science has been consistently over-egged to produce alarm. All real-world data over the past 20 years has shown the climate models to be exaggerating the likely impacts — if the models cannot account for the near term, why should I trust them in the long term?”

Model certainty at 2.7C: 20%
Model certainty at 1C: 60%

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Also worth considering is the work by Nic Lewis that showed that the IPCC have, in many cases, flattened out the probability distributions of sensitivities to give a bigger “long tail” than was in the original work.

Matt Ridley gives an overview here:

The linked post at Judith Curry’s blog

has quite a long and sometimes technical discussion on the Bayesian statistics used, and the authors of the Forster/Gregory paper pop up in the comments to say that they disagree with Nic Lewis’s conclusions.


“a ‘net’ effect somewhere in the range of 0.4°C to 4.0°C”

In other words, the effects will be somewhere between benign and catastrophic. But which end is right? The IPCC solve this profound puzzle by taking a simple average.

This is the classic case – if you have one foot encased in ice and the other in a fire, you will be comfortable ‘on average’.

Its very easy to manage. You get a high figure by including a high outlier, and vice versa.

No matter that all 17 models are known to be wrong. The average will give us the right answer with sufficient certainty for billion-dollar policy-making.

Doug Proctor

I’ve been looking at the IPCC projections with the current data. I wondered this: if the models had been run from 1960, would the error bars be the same magnitude as they are going ahead from 2010? Would the year 2010 have the same, extended error bar as in 2060?

The question relates to the models ability to predict ANYTHING. Do the models actually predict 1960 to 2010, or were the assumed variability of parameters simply dropped to that to match the observations?

Models have a major flaw which is discussed in my peer-reviewed paper linked below. Climatologists love to talk about energy being trapped by carbon dioxide and thus not exiting at the top of the atmosphere (TOA.) It is nowhere near as simple as that. All the radiation gets to space sooner or later. Carbon dioxide just scatters it on its way so you don’t see radiation in those bandwidths at TOA. The energy still gets out, and you have no proof that it doesn’t, because you don’t have the necessary simultaneous measurements made all over the world. In the hemisphere that is cooling at night there is far more getting out, whereas in the hemisphere in the sunlight there is far more coming in. This is obvious. When I placed a wide necked vacuum flask filled with water in the sun yesterday (with the lid off) the temperature of the water rose from 19.5 deg.C at 5:08am to 29.1 deg.C at 1:53pm while the air around it rose from 19.0 to 31.9 deg.C. What did the backradiation do at night? Well from 9:15pm till 12:05am the water cooled from 24.2 deg.C to 23.4… Read more »

Richard C (NZ)

Thank you Doug C for focusing minds on the screwball notion that GHG DLR warms the ocean. Dr Roy Clark shredded that idea in his US Senate EPA Submission ‘A Null Hypothesis For CO2’ 2009. But even now CSIRO and BoM are continuing to peddle bogosity to the media reporting their latest ‘State of the Climate’ report. From sky NEWS ‘Climate changing despite cool years’. Dr Karl Braganza, BoM’s climate monitoring manager:- Dr Braganza points out that most of the warming of the earth’s atmosphere is transmitted into the oceans. OK. How? Dr Paul Fraser, who leads the greenhouse gas research team:- ‘We understand the basic physics behind climate change and we understand that if you double the amount of CO2 emissions you will warm the planet‘ Again. How? The “basic physics” was presented to the US Senate by Dr Roy Clark in his EPA Submission ‘A Null Hypothesis For CO2′. In short, IR-C DLR from GHGs(+clouds) in the 4 – 16 micron range of the EM spectrum is an ineffective ocean heating agent or insulator because it only penetrates 10 microns and absorbency DECREASES 1000 times relative to IR-B in the… Read more »

Richard C (NZ)

“Human Warming at 2.7C/century should be adjusted down to approximately 1.0°C/century”

This being the luke-warmer view now coming under increasing attack from the Slayers.

Richard C (NZ)

The gloves are off now in the Slayers vs Luke-warmers showdown:-

The Strange Case of WUWT’s Anthony Watts

Climate blogger Anthony Watts perplexes his readers with a spiteful outburst against fellow skeptics of man-made global warming. The host of the world’s most read science blog has made it clear he won’t tolerate any dissent against his beloved greenhouse gas theory, the scientific cornerstone of man-made global warming alarm.


Watts has never baulked at privately bad mouthing the Slayers’ groundbreaking book,’Slaying the Sky Dragon: Death of the Greenhouse Gas Theory’ that he admits he hasn’t read. But in the last year Watts has increasingly gone public to let it be known that he refuses to countenance any debate on his website about the validity of the greenhouse gas theory, which he unquestioningly accepts.


Anthony has repeatedly stated that he does not grasp all of the science involved in this debate and depends on his bloggers and other scientists to inform him. He is rather like Spencer, who continues his rant as follows:

“…even some of us technical types end up feeling ill-equipped to argue outside our areas of expertise</em>.”

Such is how the “blind lead the blind.”



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