Warming Bias in Temperature Data due to Consensus Belief not Conspiracy

In a Cliscep article Science: One Damned Adjustment After Another? Geoff Chambers wrote:-

So is the theory of catastrophic climate change a conspiracy? According to the strict dictionary definition, it is, in that the people concerned clearly conferred together to do something wrong – namely introduce a consistent bias in the scientific research, and then cover it up.

This was in response to last the David Rose article in the Mail on Sunday, about claims the infamous the Karl et al 2015 breached America’s National Oceanic and Atmospheric Administration (NOAA) own rules on scientific intergrity.

I would counter this claim about conspiracy in respect of temperature records, even in the strict dictionary definition. Still less does it conform to a conspiracy theory in the sense of some group with a grasp of what they believe to be the real truth, act together to provide an alternative to that truth. or divert attention and resources away from that understanding of that truth. like an internet troll. A clue as to know why this is the case comes from on of the most notorious Climategate emails. Kevin Trenberth to Micheal Mann on Mon, 12 Oct 2009 and copied to most of the leading academics in the “team” (including Thomas R. Karl).

The fact is that we can’t account for the lack of warming at the moment and it is a travesty that we can’t. The CERES data published in the August BAMS 09 supplement on 2008 shows there should be even more warming: but the data are surely wrong. Our observing system is inadequate.

It is the first sentence that was commonly quoted, but it is the last part is the most relevant for temperatures anomalies. There is inevitably a number of homogenisation runs to get a single set of anomalies. For example the Reykjavik temperature data was (a) adjusted by the Iceland Met office by standard procedures to allow for known locals biases (b) adjusted for GHCNv2 (the “raw data”) (c) adjusted again in GHCNv3 (d) homogenized by NASA to be included in Gistemp.

There are steps that I have missed. Certainly Gistemp homogenize the data quite frequently for new sets of data. As Paul Matthews notes, adjustments are unstable. Although one data set might on average be pretty much the same as previous ones, there will be quite large anomalies thrown out every time the algorithms are re-run for new data. What is more, due to the nature of the computer algorithms, there is no audit trail, therefore the adjustments are largely unexplainable with reference to the data before, let alone with reference to the original thermometer readings. So how does one know whether the adjustments are reasonable or not, except through a belief in how the results ought to look? In the case of the climatologists like Kevin Trenberth and Thomas R. Karl, variations that show warmer than the previous run will be more readily accepted as correct rather than variations that show cooler. That is, they will find reasons why a particular temperature data set now shows greater higher warming than before. but will reject as outliers results that show less warming than before. It is the same when choosing techniques, or adjusting for biases in the data. This is exacerbated when a number of different bodies with similar belief systems try to seek a consensus of results, like  Zeke Hausfather alludes to in his article at the CarbonBrief. Rather than verifying results in the real world, temperature data seeks to conform to the opinions of others with similar beliefs about the world.

Kevin Marshall

Michael Mann’s bias on Hockey Sticks

Two major gripes of mine with the “Climate Consensus” are their making unsubstantiated claims from authority, and a total failure to acknowledge when one of their own makes stupid, alarmist comments that contradict the peer-reviewed consensus.

An example is from Professor Michael Mann commenting on his specialist subject of temperature reconstructions of the past for a Skeptical science “97% Consensus” spin-off campaign.

I will break this statement down.

“There are now dozens of hockey sticks and they all come to the same basic conclusion”

His view is that warming is unprecedented, shown by dozens of hockey sticks that replicate his famous graph in the UNIPCC Third Assessment Report of 2001.

Rather than look at the broader picture warming being unprecedented on any time scale1, I will concentrate on this one thousand year period. If a global reconstruction shows a hockey stick, then (without strong reasoned arguments to the contrary) one would expect the vast majority of temperature reconstructions from actual sites by various methods to also show hockey sticks

CO2Science.com, in their Medieval Warm Period Project, have catalogued loads of these reconstructions from all over the world. They split them into two categories – quantitative and qualitative differentials in the average temperature estimates between the peak of the medieval warm period and now.

It would seem to me that Mann is contradicted by the evidence of dozens of studies, but corroborated by only a few. Mann’s statement of dozens of hockey sticks reaching the same basic conclusion ignores the considerable evidence to the contrary.

“The recent warming does appear to be unprecedented as far back as we can go”

Maybe, as Mann and his fellow “scientists” like to claim, that the people behind this website are in “denial” of the science. Maybe they have just cherry-picked a few studies from a much greater number of reconstructions. So let us look at the evidence the SkS team provide. After all, it is they who are running the show. Under their article on the medieval warm period, there is the following graph of more recent climate reconstructions.

It would seem the “Mann EIV” reconstruction in green does not show a hockey stick, but flat (or gently rising) temperatures from 500-1000 AD; falling temperatures to around 1800; then an uptick starting decades before the major rise in CO2 levels post 1945. The twentieth century rise in temperatures appears to be about half the 0.7oC recorded by the thermometers, leading one to suspect that reconstructions understate past fluctuations in temperature as well. The later Ljungqvist reconstructions shows a more pronounced medieval warm period and a much earlier start of the current warming phase, in around 1700. This is in agreement with the Moberg and Hegerl reconstructions. Further the Moberg reconstruction has a small decline in temperatures post 1950.

Even worse, the graphic was from the Pages2K site. On temperature reconstructions of the last two millennia Pages2K state:-

Despite significant progress over the last few decades, we still do not sufficiently understand the precise sequence of changes related to regional climate forcings, internal variability, system feedbacks, and the responses of surface climate, land-cover, and bio- and hydro-sphere.

Furthermore, at the decadal-to-centennial timescale we do not understand how sensitive the climate is to changes in solar activity, frequency of volcanic eruptions, greenhouse gas and aerosol concentration, and land cover.

So Michael Mann’s statement if warming being unprecedented is contradicted by peer-reviewed science. Skeptical Science published this statement when it was falsified by Mann’s own published research and that of others.

“But even if we didn’t have that evidence, we would still know that humans are warming the planet, changing the climate and that represent a threat if we don’t do something about it”

There is no corroborating evidence to the climate models from temperature reconstructions. In fact, empirical data shows that the models may be claiming as human-caused temperature increases that are naturally-caused, but for reasons not fully understood. So the “knowing” must be assumed to be from belief, just as the threat and the ability of the seven billion “us” to counter that threat are beliefs as well.

Kevin Marshall



  1. The emergence from the Younger Dryas cooling period 11,500 years ago was at least 10 times the warming of the past 100 years, and was maybe in a period of less than 300 years. See WUWT article here, or the emerging story on the causes here.

Michael Mann and John Cook at Bristol University

Lucia at The Blackboard last month publicized that the John Cook is to speak at Bristol University on Dogma vs. consensus: Letting the evidence speak on climate change on Friday 19th September. There are still 395 free tickets left for the event.

Stephen Lewandowsky also notes that Michael Mann is to lecture at the same event on Tuesday 23rd September on The Hockey Stick and the climate wars – the battle continues. Just 102 free tickets left for this event.

Given the Mann’s belief that the continued climate denial is due to “massive funding of climate change denial by monied interests” (HuffPo), it might provide some light entertainment for the students.

Update 19th Sept. There are still 309 tickets left for the John Cook lecture for tomorrow – Friday 20th September. See http://www.bristol.ac.uk/cabot/events/2014/488.html

The Michael Mann lecture is now SOLD OUT, or more accurately, all the tickets have been given away.

William Connolley supports the climate faith against expert opinions

Of the current litigation by Prof. Michael Mann against The National Review and Mark Steyn, William Connolley (the Stoat) states:-

By supporting the SLAPP filing, Steyn is running away.

My reply is

You are wrong.

Steyn’s Amicus Curiae states

In particular, Steyn supports the use of the D.C. Anti-SLAPP Act to combat attempts by Plaintiff-Appellee and others to stifle public debate via the threat of protracted and inevitably expensive litigation. But in this case the anti-SLAPP process itself ……… has been manipulated by plaintiff-appellee Mann to become merely an additional phase of protracted procedural punishment.

Steyn further accuses Mann of “venue shopping” (as neither party has any connection with D.C.) and of delaying trial. He also ups the ante by accusing Mann of fraudulent claims, including that Mann was a Nobel Laureate, and that he was “exonerated” by a British Climategate Enquiry that never even mentioned him.

Steyn added:

It is clear from the ease with which Mann lies about things that would not withstand ten minutes of scrutiny in a courtroom that he has no intention of proceeding to trial.

Steyn is supported in his appeal by a separate brief undersigned by numerous organisations, such as the American Civil Liberties Union, Time Inc, The National Press Association, and Bloomberg.

To cap it all, Steyn is further supported by another brief from the District of Columbia, who view Mann’s case as being the opposite of what their anti-SLAPP legislation intended.

So there seems to be a choice here:-


You view that acceptance into the consensus cult of climatology gives you superior insights into everything, including statistics, philosophy of science, economics, public policy making, evidence evaluation, etymology and ethics.


You believe that by specializing in particular applied subject area; and comparing and contrasting views within that area; and learning from what others say in areas that impinge upon the applied specialism; and by having a wider understanding of other areas – that you may through study and application possibly gain both a deep understanding of that specialism and be able to assess the specialism in the wider context of other academic subjects and extent of knowledge and boundaries of the specialism.


Michael Mann’s narrow definition of “Skepticism”

Climate Scientist MM continues his dogged defence of the climate consensus at Thinkprogress.

Consider the following statement

Make no mistake: Skepticism is fundamental to good science. Whenever a conclusion is drawn or a proposition is made, the demand that it stand up to scrutiny is the self-correcting machinery that drives us towards a better understanding of the way the world works. In this sense, every scientist should be a skeptic. Good science responds to good faith challenges, and to contradictory evidence that is presented, and climate-change science should be no different.

The spirit of the following statement is at first beguiling, and the spirit is something that many would agree with, although “good faith challenges” allows for discrimination against people you disagree with. However, it is his meaning of “scepticism” that I want to take issue with here.

Mann’s definition is most clearly expressed by John Cook of “Skeptical Science“, but also supported by (amongst others) Tamino of “Open Mind” blog. The clearest expression is in the article “Are you a genuine skeptic or a climate denier?

Genuine skeptics consider all the evidence in their search for the truth. Deniers, on the other hand, refuse to accept any evidence that conflicts with their pre-determined views.

Compare this with a more established source of word definitions – the Oxford English Dictionary. I don’t have the full 20 volume edition, but I think my 1983 book club edition of the Shorter OED will do well enough. There are a number of definitions of “sceptic” on page 1900.

Definition 1 pertains to a school of philosophy after the Greek Pyrrho, which doubts the possibility of knowledge of any kind.

Definition 2 is someone who doubts the validity of knowledge claims in a particular area of inquiry. This includes, but is not confined to the natural sciences. In the area of climate is the Climate Realists like Tallbloke, who doubt the greenhouse gas theory.

Definition 2.1 “one who maintains a doubting attitude with reference to a particular question or statement“. The OED has this as the popular definition.

Definition 3 is one who doubts the truth of Christianity. An older definition, not applicable here.

Definition 4 is one who is seeking the truth. That is “an inquirer who has not arrived at definite convictions“. This is only occasionally used, at least in the late 20th century.

Cook’s definition is at odds with all the definitions in the dictionary. There is nothing there about how much evidence a genuine skeptic must consider. Indeed, it by his own definition Cook is not a skeptic. More seriously, Cook is disagreeing with the experts in their field. According to Cook’s definition, a skeptic is someone who formerly had a doubting attitude as in 2.1, but now has fallen into line. The philosophers are a school of deniers. (Desmogblog will no doubt now unearth evidence that they were in the pay of big olive oil producers.) Some who still doubts the truth of climate change will not have “considered all the evidence” yet. For those who have read the evidence, this category ceases to exist. The doubter of Christianity is irrelevant, whilst the seeker of truth is someone who is behind the curve.

But then who do you believe on the definition of “skeptic / sceptic”. A consensus of the world’s leading experts, or a group of dogmatic people using language for partisan purposes?

NB. I use sceptic with a “c” to denote the expert definition, and with a “k” to define the partisan definition. However, I quite realise the use of “c” was probably as a result of King George III trying the separate Britain from the revolting colonies by means of a common language.

With respect to Dr Mann, I may have got him totally wrong. Maybe he does not realise that skepticalscience.com is based on a misrepresentation. If Dr Mann (or a nominated associate) would like to clarify that he follows expert opinion, I will be more than happy to distance him from the polemicists who allegedly support him.