National Climate Assessment: A crisis of epistemic overconfidence

by Judith Curry

“You can say I don’t believe in gravity. But if you step off the cliff you are going down. So we can say I don’t believe climate is changing, but it is based on science.” – Katherine Hayhoe, co-author of the 4th National Climate Assessment Report.

So, should we have the same confidence in the findings of the recently published 4th (U.S.) National Climate Assessment (NCA4) as we do in gravity?  How convincing is the NCA4?

The 4th National Climate Assessment (NCA4) is published in two volumes:

  • Vol I: Climate Science Special Report
  • Vol II:  Impacts, Risks, and Adaptation in the United States

I’ve just completed rereading Vol I of the NCA4.  There is so much here of concern that it is difficult to know where to start.  I have been very critical of the IPCC in the past (but I will certainly admit that the AR5 was a substantial improvement over the AR4).  While the NCA4 shares some common problems with the IPCC AR5, the NCA4 makes the IPCC AR5 look like a relative paragon of rationality.

Since the NCA4 is guiding the U.S. federal government in its decision making, not to mention local/state governments and businesses, it is important to point out the problems in the NCA4 Reports and the assessment process, with two objectives:

  • provide a more rational assessment of the confidence that should be placed in these findings
  • provide motivation and a framework for doing a better job on the next assessment report.

I’m envisioning a number of blog posts on aspects of the NCA4 over the course of the next few months (here’s to hoping that my day job allows for sufficient time to devote to this).  A blog post last year Reviewing the Climate Science Special Report crowdsourced error detection on Vol. 1, with many of the comments making good points. What I plan for this series of blog posts is something different than error detection — a focus on framing and fundamental epistemic errors in approach used in the Report.

This first post addresses the issue of overconfidence in the NCA4.  I have previously argued that overconfidence is a problem with the IPCC report (see examples from Overconfidence) and the consensus seeking process; however, the overconfidence problem with the NCA4 is much worse.

Example: overconfidence in NCA4

To illustrate the overconfidence problem with the NCA4 Report, consider the following Key Conclusion from Chapter 1 Our Globally Changing Climate:

“Longer-term climate records over past centuries and millennia indicate that average temperatures in recent decades over much of the world have been much higher, and have risen faster during this time period, than at any time in the past 1,700 years or more, the time period for which the global distribution of surface temperatures can be reconstructed. (High confidence)”

This statement really struck me, since it is at odds with the conclusion from the IPCC AR5 WG1 Chapter 5 on paleoclimate:

“For average annual NH temperatures, the period 1983–2012 was very likely the warmest 30-year period of the last 800 years (high confidence) and likely the warmest 30-year period of the last 1400 years (medium confidence).

While my knowledge of paleoclimate is relatively limited, I don’t find the AR5 conclusion to be unreasonable, but it seems rather overconfident with the conclusion regarding the last 1400 years.  The NCA4 conclusion, which is stronger than the AR5 conclusion and with greater confidence, made me wonder whether there was some new research that I was unaware of, and whether the authors included  young scientists with a new perspective.

Fortunately, the NCA includes a section at the end of each Chapter that provides a traceability analysis for each of the key conclusions:

“Traceable Accounts for each Key Finding: 
1) document the process and rationale the authors used in reaching the conclusions 
in their Key Finding, 2) provide additional information to readers about the quality of
 the information used, 3) allow traceability to resources and data, and 4) describe the level of likelihood and confidence in the Key Finding. Thus, the Traceable Accounts represent a synthesis of the chapter author team’s judgment of the validity of findings, as determined through evaluation of evidence and agreement in the scientific literature.”

Here is text from the traceability account for the paleoclimate conclusion:

“Description of evidence base. The Key Finding and supporting text summarizes extensive evidence documented in the climate science literature and are similar to statements made in previous national (NCA3) and international assessments. There are many recent studies of the paleoclimate leading to this conclusion including those cited in the report (e.g., Mann et al. 2008; PAGES 2k Consortium 2013).”

“Major uncertainties: Despite the extensive increase in knowledge in the last few decades, there are still many uncertainties in understanding the hemispheric and global changes in climate over Earth’s history, including that of the last few millennia. Additional research efforts in this direction can help reduce those uncertainties.”

“Assessment of confidence based on evidence and agreement, including short description of nature of evidence and level of agreement
: There is high confidence for current temperatures to be higher than they have been in at least 1,700 years and perhaps much longer.

I read all this with acute cognitive dissonance.  Apart from Steve McIntyre’s takedown of Mann et al. 2008 and PAGES 2K Consortium (for the latest, see PAGES2K:  North American Tree Ring Proxies), how can you ‘square’ high confidence with “there are still many uncertainties in understanding the hemispheric and global changes in climate over Earth’s history, including that of the last few millennia”?

Further, Chapter 5 of the AR5 includes 1+ pages on uncertainties in temperature reconstructions for the past 200o years (section, a few choice quotes:

“Reconstructing NH, SH or global-mean temperature variations over the last 2000 years remains a challenge due to limitations of spatial sampling, uncertainties in individual proxy records and challenges associated with the statistical methods used to calibrate and integrate multi-proxy information”

“A key finding is that the methods used for many published reconstructions can underestimate the amplitude of the low-frequency variability”

“data are still sparse in the tropics, SH and over the oceans”

“Limitations in proxy data and reconstruction methods suggest that published uncertainties will underestimate the full range of uncertainties of large-scale temperature reconstructions.”

Heck, does all this even justify the AR5’s  ‘medium’ confidence level?

I checked the relevant references in the NCA4 Chapter 1; only two (Mann et al., 2008; PAGES 2013), both of which were referenced by the AR5.  The one figure from this section was from — you guessed it — Mann et al. (2008).

I next wondered: exactly who were the paleoclimate experts that came up with this stuff?  Here is the author list for Chapter 1:

Wuebbles, D.J., D.R. Easterling, K. Hayhoe, T. Knutson, R.E. Kopp, J.P. Kossin, K.E. Kunkel, A.N. LeGrande, C. Mears, W.V. Sweet, P.C. Taylor, R.S. Vose, and M.F. Wehner

I am fairly familiar with half of these scientists (a few of them I have a great deal of respect for), somewhat familiar with another 25%, and unfamiliar with the rest.  I looked these up to see which of them were the paleoclimate experts.  There are only two authors (Kopp and LeGrande) that appear to have any expertise in paleoclimate, albeit on topics that don’t directly relate to the Key Finding.   This is in contrast to an entire chapter in the IPCC AR5 being devoted to paleoclimate, with substantial expertise among the authors.

A pretty big lapse, not having an expert on your author team related to one of 6 key findings.  This isn’t to say that a non-expert can’t do a good job of assessing this topic with a sufficient level of effort.  However the level of effort here didn’t seem to extend to reading the IPCC AR5 Chapter 5, particularly section

Why wasn’t this caught by the reviewers?  The NCA4 advertises an extensive in house and external review process, including the National Academies.

I took some heat for my Report On Sea Level Rise and Climate Change, since it had only a single author and wasn’t peer reviewed.  Well, the NCA provides a good example of how multiple authors and peer review is no panacea for providing a useful assessment report.

And finally, does this issue related to whether current temperatures were warmer than the medieval warm period really matter?  Well yes, it is very important in context of detection and attribution arguments (which will be the subject of forthcoming posts).

This is but one example of overconfidence in the NCA4.  What is going on here?

Confidence guidance in the NCA4

Exactly what does the NCA4 mean by ‘high confidence’? The confidence assessment used in the NCA4 is essentially the same as that used in the IPCC AR5.  From the NCA4:

“Confidence in the validity of a finding based on the type, amount, quality, strength, and consistency of evidence (such as mechanistic understanding, theory, data, models, and expert judgment); the skill, range, and consistency of model projections; and the degree of agreement within the body of literature.”

“Assessments of confidence in the Key Findings are based on the expert judgment of the author team.  Confidence should not be interpreted probabilistically, as it is distinct from statistical likelihood. “

These descriptions for each confidence category don’t make sense to me; the words ‘low’, ‘medium’ etc. seem at odds with the descriptions of the categories.  Also, I thought I recalled a ‘very low’ confidence category from the IPCC AR5 (which is correct link).  The AR5 uncertainty guidance doesn’t give verbal descriptions of the confidence categories, although it does include the following figure:

The concept of ‘robust evidence’ will be considered in a subsequent post; this is not at all straightforward to assess.

The uncertainty guidance for the AR4 provides some insight into what is actually meant by these different confidence categories, although this quantitative specification was dropped for the AR5:

Well this table is certainly counterintuitive to my understanding of confidence.  If someone told me that their conclusion had 1 or 2 chances out of 10 of being correct, I would have no confidence in that conclusion, and wonder why we are even talking about ‘confidence’ in this situation.  ‘Medium confidence’ implies a conclusion that is  ‘as likely as not;’ why have any confidence in this category of conclusions, when an opposing conclusion is equally likely to be correct?

Given the somewhat flaky guidance from the IPCC regarding confidence, the NCA4 confidence descriptions are a step in the right direction regarding clarity, but the categories defy the words used to describe them. For example:

  • ‘High confidence’ is described as ‘Moderate evidence, medium consensus.’  The words ‘moderate’ and ‘medium’ sound like ‘medium confidence’ to me.
  • ‘Medium confidence’ is described as ‘Suggestive evidence (a few sources, limited consistency, models incomplete, methods emerging); competing schools of thought.’  Sounds like ‘low confidence’ to me.
  • ‘Low confidence’ is described as inconclusive evidence, disagreement or lack of opinions among experts.  Sounds like ‘no confidence’ to me.
  • ‘Very high confidence’ should be reserved for evidence where there is very little chance of the conclusion being reversed or whittled down by future research; findings that have stood the test of time and a number of different challenges.

As pointed out by Risbey and Kandlikar (2007), it is very difficult (and perhaps not very meaningful) to disentangle confidence from likelihood when the confidence level is medium or low.

Who exactly is the audience for these confidence levels?  Well, other scientists, policy makers and the public.  Such misleading terminology contributes to misleading overconfidence in the conclusions — apart from the issue of the actual judgments that go into assigning a confidence level to one of these categories.

Analyses of the overconfidence problem

While I have written previously on the topic of overconfidence, it is good to be reminded and there are some insightful new articles to consider.

Cassam (2017) Overconfidence is an epistemic vice. Excerpts (rearranged and edited without quote marks):

‘Overconfidence’ can be used to refer to positive illusions or to excessive certainty. The former is the tendency to have positive illusions about our merits relative to others. The latter describes the tendency we have to believe that our knowledge is more certain that it really is. Overconfidence can cause arrogance, and the reverse may also be true. Overconfidence and arrogance are in a symbiotic relationship even if they are distinct mental properties.

Cassam distinguishes four types of overconfidence:

  1. Personal explanations attribute error to the personal qualities of individuals or groups of individuals. Carelessness, gullibility, closed-mindedness, dogmatism, and prejudice and wishful thinking are examples of such qualities. These qualities are epistemic vices.
  2. Sub-personal explanations attribute error to the automatic, involuntary, and non-conscious operation of hard-wired cognitive mechanisms. These explanations are mechanistic in a way that personal explanations are not, and the mechanisms are universal rather than person-specific.
  3. Situational explanations attribute error to contingent situational factors such as time pressure, distraction, overwork or fatigue.
  4. Systemic explanations attribute error to organizational or systemic factors such as lack of resources, poor training, or professional culture.

To the extent that overconfidence is an epistemic vice that is encouraged by the professional culture, it might be described as a ‘professional vice’.

Apart from the epistemic vices of individual climate scientists (activism seems to the best predictor of such vices), my main concern is the systematic biases introduced by the IPCC and NCA assessment processes – systemic ‘professional vice’.

Thomas Kelly explains how such a systematic vice can work, which was summarized in my 2011 paper Reasoning about Climate Uncertainty:

Kelly (2008) argues that “a belief held at earlier times can skew the total evidence that is available at later times, via characteristic biasing mechanisms, in a direction that is favorable to itself.” Kelly (2008) also finds that “All else being equal, individuals tend to be significantly better at detecting fallacies when the fallacy occurs in an argument for a conclusion which they disbelieve, than when the same fallacy occurs in an argument for a conclusion which they believe.” Kelly (2005) provides insights into the consensus building process: “As more and more peers weigh in on a given issue, the proportion of the total evidence which consists of higher order psychological evidence [of what other people believe] increases, and the proportion of the total evidence which consists of first order evidence decreases . . . At some point, when the number of peers grows large enough, the higher order psychological evidence will swamp the first order evidence into virtual insignificance.” Kelly (2005) concludes: “Over time, this invisible hand process tends to bestow a certain competitive advantage to our prior beliefs with respect to confirmation and disconfirmation. . . In deciding what level of confidence is appropriate, we should taken into account the tendency of beliefs to serve as agents in their own confirmation.  Kelly refers to this phenomenon as  ‘upward epistemic push.’

The Key Finding regarding paleo temperatures described above is an example of upward epistemic push: the existence of a ‘consensus’ on this issue resulted in ignoring most of the relevant first order evidence (i.e. publications), combined with an apparent systemic desire to increase confidence relative to the NCA3 conclusion.

Walters et al. (2016) argues that overconfidence is driven by the neglect of unknowns. Overconfidence is also driven by biased processing of known evidence in favor of a focal hypothesis (similar to Kelly’s argument). Overconfidence is also attributed to motivated reasoning and protecting one’s self image from failure and regret (political agenda and careerism).

Kahneman (2011) refers to as the ‘What You See is All There Is’ (WYSIATI) principle, in context on focusing on known relative to unknown information.

I would say that all of the above are major contributors to systemic overconfidence related to climate change.

Solutions to overconfidence

I have written multiple blog posts previously on strategies for addressing overconfidence, including:

From Kelly (2005):

“It is sometimes suggested that how confident a scientist is justified in being that a given hypothesis is true depends, not only on the character of relevant data to which she has been exposed, but also on the space of alternative hypotheses of which she is aware. According to this line of thought, how strongly a given collection of data supports a hypothesis is not wholly determined by the content of the data and the hypothesis. Rather, it also depends upon whether there are other plausible competing hypotheses in the field. It is because of this that the mere articulation of a plausible alternative hypothesis can dramatically reduce how likely the original hypothesis is on the available data.”

From Walters (2016):

“Overconfidence can be reduced by prompting people to ‘consider the alternative’ or by designating a member of a decision-making team to advocate for the alternative (‘devil’s advocate technique’).”

“Our studies show that the evaluation of what evidence is unknown or missing is an important determinant of judged confidence. However, people tend to underappreciate what they don’t know. Thus, overconfidence is driven in part by insufficient consideration of unknown evidence.”

“We conceptualize known unknowns as evidence relevant to a probability assessment that a judge is aware that he or she is missing while making the assessment. We distinguish this from unknown unknowns, evidence that a judge is not aware he or she is missing. It is useful at this point to further distinguish two varieties of unknown unknowns. In some cases a judge may be unaware that he or she is missing evidence but could potentially recognize that this evidence is missing if prompted. We refer to these as retrievable unknowns. In other cases, a judge is unaware that he or she is missing evidence and furthermore would need to be educated about the relevance of that evidence in order to recognize it as missing. We refer to these as unretrievable unknowns.”

“Considering the unknowns may also be more effective than considering the alternative in judgment tasks where no obvious alternative exists. A hybrid strategy of considering both the unknowns and the alternative may be more effective than either strategy alone.”

 JC reflections

Nearly everyone is overconfident.  See these previous articles:

The issue here is overconfidence of scientists and ‘systemic vice’ about policy-relevant science, where the overconfidence harms both the scientific and decision making processes.

I don’t regard myself as overconfident with regards to climate science; in fact some have accused me of being underconfident.  My experience in owing a company that makes weather and climate predictions (whose skill is regularly evaluated) has been extremely humbling in this regard.  Further, I study and read the literature from philosophy of science, risk management, social psychology and law regarding uncertainty, evidence, judgement, confidence, argumentation.

The most disturbing point here is that overconfidence seems to ‘pay’ in terms of influence of an individual in political debates about science.  There doesn’t seem to be much downside for the individuals/groups to eventually being proven wrong.   So scientific overconfidence seems to be a victimless crime, with the only ‘victim’ being science itself and then the public who has to live with inappropriate decisions based on this overconfident information

So what are the implications of all this for understanding overconfidence in the IPCC and particularly the NCA? Cognitive biases in the context of an institutionalized consensus building process have arguably resulted in the consensus becoming increasingly confirmed in a self-reinforcing way, with ever growing confidence. The ‘merchants of doubt’ meme has motivated activist scientists (as well as the institutions that support and assess climate science) to downplay uncertainty and overhype confidence in the interests of motivating action on mitigation.

There are numerous strategies that have been studied and employed to help avoid overconfidence in scientific judgments.  However, the IPCC and particularly the NCA introduces systemic bias through the assessment process, including consensus seeking.

As a community, we need to do better — a LOT better.  The IPCC actually reflects on these issues in terms of carefully considering uncertainty guidance and selection of a relatively diverse group of authors, although the core problems still remain.  The NCA appears not to reflect on any of this, resulting in a document with poorly justified and overconfident conclusions.

Climate change is a very serious issue — depending on your perspective, there will be much future loss and damage from either climate change itself or from  the policies designed to prevent climate change.  Not only do we need to think harder and more carefully about this, but we need to think better, with better ways justifying our arguments and assessing uncertainty, confidence and ignorance.

Sub-personal biases are unavoidable, although as scientists we should work hard to be aware and try to overcome these biases.  Multiple scientists with different perspectives can be a big help, but it doesn’t help if you assign a group of ‘pals’ to do the assessment.  The issue of systemic bias introduced by institutional constraints and guidelines is of greatest concern.

The task of synthesis and assessment is an important one, and it requires some different skills than a researcher pursuing a narrow research problem.  First and foremost, the assessors need to do their homework and read tons of papers, consider multiple perspectives, understand sources of and reasons for disagreement, play ‘devils advocate’, and ask ‘how could we be wrong?’

Instead, what we see in at least some of the sections of the NCA4 is bootstrapping on previous assessments and then inflating the confidence without  justification.

More to come, stay tuned.

Moderation note:  this is a technical thread, and I am requesting that comments focus on

  • the general overconfidence issue
  • additional examples (with documentation) of unjustified, overconfident conclusions (e.g. relative to the AR5)

I am focusing on Vol 1 here, since Vol 2 is contingent on the conclusions from Vol 1.  General comments about the NCA4 can be made on the week in review or new year thread.  Thanks in advance for your comments.


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George Williams
January 2, 2019 6:31 pm

Al Gore and company claim that the science is settled, then how can the AGW warmers defend the continuation of the existance of the investigative body known as the IPCC. It’s time to call their bluff by abandoning opposition to the warmers, at least publicly, and calling for defunding it, not based upon the fraud that we know exists, but because the ostensible justification for the it no longer exists. Let’s see their strategy for maintaining their empire.

Reply to  George Williams
January 2, 2019 7:48 pm

“You can say I don’t believe in gravity. But if you step off the cliff you are going down. So we can say I don’t believe climate is changing, but it is based on science.” – Katherine Hayhoe, co-author of the 4th National Climate Assessment Report.

If there was a Nobel Prize for utter vapid stupidity, the above statement by Ms. Hayhoe would get my vote.

The fact that so many politicians, journalists and educators believe this sort of hysterical nonsense is truly disturbing – these imbeciles run our society, influence it through the media, and teach our children!

The great American philosopher George Carlin said,
“Think about how stupid the average person is, and then realize that half of them are stupider than that!”

January 2, 2019 7:54 pm

You can claim that the Earth is going to burn up and the science is settled, but when the thermometer show the Earth is cooling, you are still WRONG!

January 2, 2019 8:32 pm

Hillary fans and North Koreans – crying.

Hillary fans crying.

North Koreans crying.

January 3, 2019 5:34 am

She could win the Nobel prize for disingenuous too.

“So we can say I don’t believe climate is changing, but it is based on science.”

Who doesn’t believe the climate is changing?

Reply to  Craig
January 3, 2019 6:25 am

Hers was just a devious way of accusing humans of a natural phenomena that lets government usurp control of the populace!

Very clever, these bureaucrats!

Reply to  Craig
January 3, 2019 9:28 am

And what does she mean by “based on science”? I’ve seen films “based on” books I know well which bear not an ounce of resemblance to the original!

Andy Pattullo
January 3, 2019 7:54 am

I don’t believe Katherine Hahoe is being stupid in making this statement, she is being deceptive and trying to obscure the real debate. It is a commonly used tactic to suggest that we are having a debate about whether climate is changing when the debate is really about how much, in what direction, caused by what drivers and whether it will be worse or better for humankind, the biosphere and earth in general. It is important for the enforcers of the consensus to redirect the argument this way because the real issues are entirely in doubt and that doubt would not cause voters and those whose self interest is threatened to support all of the draconian policy prescriptions that are designed to enrich and empower the promoters of this fraud.

Steve O
Reply to  Andy Pattullo
January 4, 2019 8:16 am


Gordon Dressler
January 3, 2019 9:27 am

Katherine Hayhoe, it’s nice that you co-authored the 4th National Climate Assessment Report. Now, since you’ve used the term so freely, can you please define for us precisely what you mean by “climate change”.

“If you can’t define something you have no formal rational way of knowing that it exists. Neither can you really tell anyone else what it is. There is, in fact, no formal difference between inability to define and stupidity.” — Robert M. Pirsig

Phil R
Reply to  Gordon Dressler
January 3, 2019 10:21 am

What can be asserted without evidence can be dismissed without evidence.

Phil R
January 3, 2019 10:17 am


You say:

“If there was a Nobel Prize for utter vapid stupidity, the above statement by Ms. Hayhoe would get my vote.” I respectfully suggest that vapid is not the correct word.

vapid adjective
va·​pid | \ˈva-pəd,

Definition of vapid: lacking flavor, zest, interest, animation, or spirit : flat, dull.

I think: “utter vapid weapons-grade stupidity” is more accurate.

January 3, 2019 3:04 pm

“You can say I don’t believe in gravity. But if you step off the cliff you are going down. So we can say I don’t believe climate is changing, but it is based on science.” – Katherine Hayhoe, co-author of the 4th National Climate Assessment Report.

Let’s take it a step further, to explain WHY Hayhoe’s above statement displays such “utter vapid stupidity”:

Her statement operates on the stupid assumption that climate skeptics don’t believe that climate is changing. I don’t know of a single climate-change skeptic who doesn’t believe that climate changes.

Climate-change skeptics KNOW and UNDERSTAND that climate is changing, … climate has always changed, … and climate will continue to change, as it always has. Hayhoe’s implication that climate-change skeptics reject this basic knowledge is false representation to the point of lying about what a climate-change skeptic actually believes.

The first mark of utter vapid stupidity, then, is her putting forth not only a straw man, but a straw man made of rotten straw.

The second mark of utter vapid stupidity would be her using this rotten straw man to compare climate-change skeptics to people who disbelieve gravity.

What climate change skeptics really believe is that human-produced CO2 is not the cause of climate change. Failure to make this proper distinction is, I would add, almost criminally stupid, thus making for its total lack of substance that feeds the vapid part of Allan M’s characterization of her statement.

Steve O
Reply to  Robert Kernodle
January 4, 2019 8:22 am

I’ve found that many of those in the alarmist camp sincerely have no idea about the objections to their positions. We’re either ignorant, shills for the “fossil fuel lobby” or we want to see the world burn.

Before starting a discussion with someone, I sometimes ask them up front what they think is the mainstream skeptic position.

Kurt Linton
January 4, 2019 6:01 am

Of course, it is not the acme of intelligence to confuse average with median…but I think we know what Carlin was implying.

Reply to  George Williams
January 2, 2019 8:21 pm

As long as climate changes the IPCC will be essential. Hence why it was not called IPGW.

Reply to  WXcycles
January 2, 2019 10:48 pm

“As long as climate changes the IPCC will be essential. ”

Not a bad earner if you can get it.
Climate change has a history of about 4.2Gy.
That’s a job for life [all life].

Reply to  George Williams
January 3, 2019 8:15 am

The physics of climate change is unknown,
except for a reasonable list of “suspects”.

We have over 50 years of wrong climate predictions
to prove that.

Therefore, predictions of the future climate made today
are nothing more than wild guesses, or opinions.

There is no logical reason to apply a “confidence level”
to a wild guess, or an opinion !

In fact, what is called “confidence level” is meaningless !

From a climate science article I posted on my
climate science blog today:

The IPCC states it is
“extremely likely”
human emissions
have been the
dominant cause
of global warming
“since the mid-20th century”
( since 1950 )

The IPCC also claims
that “extremely likely”
means 95% certain,
even though
the number 95
was plucked
from the air,
like magic.”
Predictions of the future climate
in any more detail than expectations
of a repeating 100,000-year
Milankovitch cycle, are just wild guesses !

Wild guesses of the future climate
are junk science !

My climate science blog
(with mo wild guess predictions
of the future climate, because
they are junk science, not real science:

Gordon Dressler
Reply to  Richard Greene
January 3, 2019 10:05 am

Well, there is an easy and self-evident way to test the IPCC claim that it is “extremely likely” human emissions have been the dominant cause of global warming “since the mid-20th century” (since 1950).

Let’s look at the scientific evidence: the preponderance of scientific data—yes, even the massaged data—clearly shows that from about 1941 to 1975 Earth actually cooled globally, and from about 2001 to present day Earth either ceased warming entirely or warmed at a rate an order of magnitude less than the maximum rate seen previously over 18-year spans. And these two intervals occurred with Earth’s greenhouse gases, excluding water vapor, increasing on an ever-upward yearly trend.

So, in 44 (24+18) out of the last 68 (2018-1950) years, annual average global temperature—however that is calculated, as long as it is done so consistently—has clearly been dominated by some factor(s) other than CO2 as a greenhouse gas, let alone that increase of atmospheric CO2 that might be attributed solely to human origination.

The logical conclusion of any objective, fair-minded scientist or lay person would be that there is NO confidence that human emissions have been the dominant cause of global warming since 1950.


Gordon Dressler
Reply to  Gordon Dressler
January 3, 2019 10:15 am

ctm . . . well, my poor job of editing after two re-reads prior to posting: make that third paragraph above start with: “So, in 42 (24+18) out of the last 68 . . . ”


Reply to  Gordon Dressler
January 5, 2019 2:51 pm

Or how about two 30 year periods from 1910 – 1940 and 1970 – 2000, both look like the linear regression line looks like the same slope to me.
Agreed that is HadCrut 3, but after they revised the data for 4, the trend is still there only not exactly the same.

Reply to  Gordon Dressler
January 5, 2019 5:06 pm

One might examine the 30 year rate of global warming between 1910-1940 compared to 1970 -2000. I created this many years ago and it was strong evidence to me.

C Earl Jantzi
Reply to  George Williams
January 6, 2019 1:01 pm

IPCC official, Ottmar Edenhofer, speaking in November 2010: “But one must say clearly that we redistribute, de facto, the world’s wealth by climate policy. … one has to free oneself from the illusion that international climate policy is environmental policy. Instead, climate change policy is about how we redistribute, de facto, the world’s wealth…” “This has almost nothing to do with environmental policy, anymore.” http://www.nzzDOTch/aktuell/startseite/klimapolitik-verteilt-das-weltvermoegen-neu-1.8373227

C Earl Jantzi
Reply to  C Earl Jantzi
January 6, 2019 1:03 pm

2Jan2015 At a news conference [22Jan2015] in Brussels, Christiana Figueres, executive secretary of U.N.’s Framework be adopted Convention on Climate Change, admitted that the goal of environmental activists is not to save the world from ecological calamity but to destroy capitalism. “This is the first time in the history of mankind that we are setting ourselves the task of intentionally, within a defined period of time, to change the economic development model that has been reigning for at least 150 years, since the Industrial Revolution,” she said . Referring to a new international treaty environmentalists hope will at the Paris climate change conference later this year, she added: “This is probably the most difficult task we have ever given ourselves, which is to intentionally transform the economic development model for the first time in human history.”
Investor’s Business Daily: http://news.investors DOTcom/ibd-editorials/021015-738779-climate-change-scare-tool-to-destroy-capitalism.htm#ixzz3RXh5Tujn

January 2, 2019 6:32 pm

“You can say I don’t believe in gravity. But if you step off the cliff you are going down. So we can say I don’t believe climate is changing, but it is based on science.”

I don’t know if she meant to say “scientism” or “political science”.

At any rate, the conflation is deliberate; no different when a politician uses “immigrant” for “illegal immigrant” then scolds people for wanting identifiable borders.

Reply to  AWG
January 2, 2019 6:51 pm

Worse than that.

First, there’s no such thing as an “illegal immigrant”. You apply for immigration status, and if it is granted, you can immigrate. Legally. If you haven’t been granted immigrant status, you cannot be an immigrant of any sort.

Second, as for gravity, well that’s not science, that’s observations of past events, the conclusion being that the same thing will happen each and every time you step off a cliff. Climate science on the other hand has nothing to do with repeatability. It is predicting future events that are, (their words), unprecedented.

Reply to  davidmhoffer
January 2, 2019 11:02 pm

“Second, as for gravity, well that’s not science, that’s observations of past events, the conclusion being that the same thing will happen each and every time you step off a cliff. ”

Seems like science to me..

The scientific method begins with scientists forming questions, or hypotheses, and then acquiring the knowledge through observations and experiments to either support or disprove a specific theory. from

You don’t have to be a SCIENTIST to be a scientist

Then you discover that your general case has instances when it doesn’t work.
You step off that cliff and there is an updraft so you don’t fall.
You have to modify your hypothesis on the basis of further observations until along comes Einstein and says ..”Sorry Isaac but your theory only works in particular circumstances but more generally my theory is better”. Well Bert probably didn’t say that but the rest of us did.

Then along comes we don’t know who yet with a theory that explains stuff that Bert’s theory couldn’t and so it goes

Dr Deanster
Reply to  GregK
January 3, 2019 6:47 am

Greg … I think what he is getting at, is the fact that if you step off a cliff you will fall is an observation. The “why” you will fall falls in the realm of science. As such the falling, and gravity are often interchanged. Falling is an observation. Gravity is a force studied by science.

Matt Bergin
Reply to  davidmhoffer
January 3, 2019 2:35 am

David that is why I use the old term Illegal alien. Works for everyone who doesn’t belong even little green men from Mars. 😉

James Beaver
Reply to  Matt Bergin
January 3, 2019 6:31 am

I’d bet that the Martians are actually a rusty brown color. We haven’t seen them because they blend right into the scenery.

George Williams
Reply to  davidmhoffer
January 3, 2019 5:52 am

The scientific method includes making repeated observations. Aside from proving that
gravity attracts masses to each other, the strength of these attractions is proven by observations. These observations are used to predict future events based upon the parameters of mass , time and proximity. The theory of gravity was proven by repeated measurements. And yes, even climate change involved science, the rekationships between temperature, CO2 concentrations, and the thermodynamic, radiative, conductive and convective, as well as the properties of gasses, vapors and solids and of course time.

Dr Deanster
Reply to  George Williams
January 3, 2019 7:04 am

Yet … at no time has Climate Science correctly incorporated the GHG properties of CO2 into the greater climate system. They most certainly have not done so repeatedly. Further, all of their exercises are in the virtual world of modeling, and no model has yet proven to be correct when compared to real observation within the climate system.

This is the heart of the real Climate Debate for people like me. Alarmists continually try to change the argument to things like … pp so you don’t think CO2 is a GHG …. or you don’t agree there is a GHG effect, …. or you don’t agree the globe has warmed. NONE of these are part of the debate. The question is, what is the quantitative impact of CO2 GHG effect WITHIN THE CLIMATE SYSTEM.

The answer to question is unknown at this time.

AGW is not Science
Reply to  Dr Deanster
January 3, 2019 7:23 am

Actually not unknown – the Earth’s climate history shows its effect to be NIL.

See the Geocarb paleoclimate reconstructions (over hundreds of millions of years) – NO correlation, plus significant episodes of REVERSE correlation, and certainly no “CO2 drives temperature” relationship whatsoever.

See the ice core paleoclimate reconstructions (tens of thousands of years) – a correlation exists, but runs exactly IN REVERSE – it is TEMPERATURE that drives CO2 levels, NOT CO2 driving temperature. CO2 level changes FOLLOW temperature changes, UP AND DOWN, like a DOG on a LEASH.

CO2 doesn’t DRIVE anything.

Reply to  AWG
January 2, 2019 7:41 pm

A climate thot (“Hey, ho”) prostitutes science.

Craig from Oz
Reply to  AWG
January 2, 2019 8:39 pm

The effects and evidence of gravity are easily observable and easy to replicate.

The evidence of a (man made) changing climate? Can we observe that?

The effects of CO2 on global temperature? Can we observe that? Can we replicate?

Yeah… Let’s face it, if Ms Heyhoe is using this as her opening argument you can pretty much cut straight to the end. She is attempting to confuse the issue by comparing apples to pixels and belittle any voice of disagreement by strongly implying they are scientific failures to spend their outdoor lives in slack jaw wonder before stumbling down cliff faces.

I do strongly expect Ms Heyhoe does understand science (and cliff faces), but has however deliberately decided to belittle critics rather than debate them. Disappointing.

George Daddis
Reply to  AWG
January 3, 2019 8:04 am

Sometimes it is only necessary to untangle Progressives’ twisted logic. An acquaintance used the same example in a conversation just last week. (I didn’t realize the source.)

“You can say I don’t believe in gravity. But if you step off the cliff you are going down. So we can say I don’t believe climate is changing, but it is based on science.” (sic)

My response was that indeed we know by repeated observation that if you drop something it will fall to the ground. Although no one “denies” the existence of gravity, the science behind WHY an object falls is far from settled.

In a similar fashion, no one I know denies that the climate changes; the unsettled question is WHY.

The example posed to me came from a fellow layperson. The quote from Hayhoe indicates she is either ignorant or disingenuous; either one disqualifies her from being worthy of consideration as a scientist.

January 2, 2019 6:35 pm


“Reposted trom Judith Curry’s Climate Etc. (from)

January 2, 2019 6:43 pm

“You can say I don’t believe in gravity. But if you step off the cliff you are going down. So we can say I don’t believe climate is changing, but it is based on science.” – Katherine Hayhoe, co-author of the 4th National Climate Assessment Report.

Something not right there – who is this “we” that is saying the climate isn’t changing?

The discussion shouldn’t be about whether the climate is changing. By any reasoning, there is a high degree of certainty that the climate is changing.

However, regarding the factors that contribute to that change and the degree each factor has on the change, would it be safe to say there is a high degree of uncertainty?

January 2, 2019 6:50 pm

In addition to proxy evidence, we have to consider written history as well as archaeological evidence. link The evidence is that crops which now can’t be grown reliably, and couldn’t be grown at all during the Little Ice Age (LIA) could be grown reliably during the Medieval Warm Period (MWP). We have evidence from Europe, China, Africa, and even the (admittedly short lived) Viking settlements in North America. link The early European settlers of North America certainly experienced the effects of the LIA.

It’s relatively easy to monkey with proxy evidence. It is much harder to alter the historical record. For me, it is written history that proves that Dr. Mann’s hockey stick is completely bogus.

Reply to  commieBob
January 3, 2019 5:51 am

In addition to historical written records, retreating glaciers are revealing artifacts and flora (trees and the like) that are thousands (not millions) of years old. So, I have VERY HIGH CONFIDENCE (certainty,actually) that the recent warming is not unprecedented within this interglacial period.

And I have VERY HIGH CONFIDENCE (certainty, actually) that human civilization and humans in general fared far better during warm periods than cold periods.

I also have VERY HIGH CONFIDENCE (certainty, actually) that 100% of the species currently “threatened” by AGW lived on earth during this entire interglacial period.

And I have VERY HIGH CONFIDENCE (certainty, actually) that none of historical record nor the “near” paleo record will ever be cited in a National Climate Assessment (NCA) due to the corruption of science.

AGW is not Science
Reply to  DocSiders
January 3, 2019 7:14 am

I am certain that you are right, and the climate whores like Hay-HOE are wrong.

The notion that human-induced climate catastrophe is “factual” in a manner comparable to the force of gravity is so unbelievably stupid that it being asserted by someone who even PRETENDS to be a “scientist” devalues science to the level of fortune telling. There is not ONE SCRAP of evidence that atmospheric CO2 level drives the Earth’s temperature. NONE. It’s just HYPOTHETICAL bullshit and extrapolation from there. The Earth’s climate history CONTRADICTS, not supports, their assertions. When your so-called “science” disagrees with real-world observations, it’s time to admit your pet hypothesis is wrong and move on.

J Mac
January 2, 2019 6:52 pm

Clearly, the definitions applied to the different ‘confidence levels’ seem grossly inappropriate, at least to engineer!
If an engineer proposed such imprecise and inappropriate ‘confidence levels’ for assessment of any data/project review involving economic and/or human risks, their credibility with their peers and senior engineers would be destroyed. And rightfully so!

Rick C PE
Reply to  J Mac
January 2, 2019 7:26 pm

Yup. If a safety engineer said he had high confidence that a toaster design would not start a fire or electrocute a user based on a 9 out of 10 chance, would anyone allow it to be sold? In engineering certainty is often a function of extensive testing, 3 sigma limits and a safety factor of 3 or more.

Clyde Spencer
Reply to  Rick C PE
January 2, 2019 7:39 pm

Rick C PE

I would call 9 out of 10 “Confidence,” 5 out of 10 “Very Low Confidence,” and 1 out of 10 “No Confidence.”

Rick C PE
Reply to  Clyde Spencer
January 2, 2019 7:55 pm

Clyde: In fact, saying that “X” will happen with low (1 out of 10) confidence is exactly the same as saying “X” won’t happen with high (9 out of 10) confidence under the IPCC system.

Reply to  J Mac
January 2, 2019 7:51 pm


Having been in both engineering and sales I can say the “confidence” levels describe the likelihood of making a sale (“Very High Confidence” – At least 9 out of 10 chance). Very appropriate for Climate Science.

NOTHING of a technical engineering nature would ever be acceptable with a likelihood of “at least 9 out of 10” of working, or being correct. What a joke.

JC – many thanks for doing this. Don’t know how you keep your composure. I can’t bear even reading much of it, let alone documenting inconsistencies and applying logic and reasonableness as well as you do. Way too quickly I just lose it, “Where do they get these people?” and “what is wrong with them?”

Reply to  BobM
January 3, 2019 3:00 am

9 our of 10 is generally the standard for high confidence. When assessing the potential of oil & gas prospects, p90 (90% probability) is considered to be the minimum economic case. P50 is considered the most likely case and p10 is the maximum case.

It’s also the standard for proved oil & gas reserves:
90% probability = Proved reserves (1p)
>50% to <90% probability = Probable reserves (2p)
<50% probability = possible reserves (3p, not bookable)

This is why, when assessed correctly, proved reserves will initially increase with production.

Jeff Alberts
January 2, 2019 6:57 pm

JCurry: “While my knowledge of paleoclimate is relatively limited, I don’t find the AR5 conclusion to be unreasonable”

I do. To my knowledge, no paleo proxy has the predictive skill, nor the temporal resolution to show a 30 year change in anything.

Greg F
Reply to  Jeff Alberts
January 2, 2019 9:36 pm

I do. To my knowledge, no paleo proxy has the predictive skill, nor the temporal resolution to show a 30 year change in anything.

Perhaps they should be sent a copy of Claude Shannon’s “A mathematical theory of communication”.

Reply to  Jeff Alberts
January 3, 2019 3:14 am

Law Dome and most Greenland ice cores have better than 30-yr temporal resolutions and the d18O signal can usually be calibrated to instrumental data.

Tree ring chronologies also have better than 30-yr temporal resolution; however they aren’t particularly reliable proxies.

Mann 08, Moberg 05, etc have better than 10-yr temporal resolutions; but under-represent the amplitude of the temperature signal. And… Mann’s “trick” of splicing instrumental data onto proxy data invalidates everything he does.

Longer multi-proxy reconstructions like Marcott 2014 have 150 to 400-yr resolutions and cannot ethically be directly compared to instrumental data, which would be a single data point at a comparable resolution.

January 2, 2019 7:00 pm

Excellent article!
Thank you!

Flight Level
January 2, 2019 7:17 pm

How many “sciences” have come to seek support for their bogus results by politicians, binding laws, public relations, militant groups, NGO’s, street parades, United Nations, media, campaigners, financial institutions and so on ? All at the same time ?

Have you ever heard a mathematician call his colleague “denier” and claim zillions of dollars to feed a “mathematics fund” ?

Is there any science that lays down hypothesis based on presumptions fed computer models and use other equally tweaked computer models as proof ?

Can you imagine the consequences of engineers making that much “mistakes” as climate guys get away with ?

Would a physicist “believe” or work out the maths behind ?

Is there another so called science that exhibits so many similarities with a full blown dogmatic cult ?

Tom Abbott
January 2, 2019 7:20 pm

From the article: “Example: overconfidence in NCA4

To illustrate the overconfidence problem with the NCA4 Report, consider the following Key Conclusion from Chapter 1 Our Globally Changing Climate:

“Longer-term climate records over past centuries and millennia indicate that average temperatures in recent decades over much of the world have been much higher, and have risen faster during this time period, than at any time in the past 1,700 years or more, the time period for which the global distribution of surface temperatures can be reconstructed. (High confidence)”

That doesn’t apply to the United States.

One only has to go back to 1934 on the US temperature chart to find a time when the temperature was higher than today. Higher than 1998, by about 0.5C, and higher than 2016 by about 0.4C.

Here’s Hansen’s 1999 US surface temperature chart:

comment image

And of course, there are other unmodified surface temperature charts from around the world that resemble Hansen 1999 very closely, i.e., the 1930’s were as warm or warmer than today. So the Hansen 1999 chart is actually representative of the unmodified charts you will find from all over the world, in both hemispheres.

This Hansen 1999 temperature profile is the true global temperature profile: The 1930’s was as warm or warmer than subsequent years across the globe.

What this means is we are not currently experiencing unprecedented warmth, it is no warmer today than in the 1930’s. And, according to the IPCC, CO2 did not have a significant effect until 1950 and beyond, which means the warmth of the 1930’s was due to Mother Nature/Natural Variability, not CO2, and since current temperatures are equivalent to 1930’s temperatures, there is no need to invoke CO2 for the current warming.

Reply to  Tom Abbott
January 2, 2019 8:39 pm

Tom Abbott: That doesn’t apply to the United States. One only has to go back to 1934 on the US temperature chart to find a time when the temperature was higher than today. Higher than 1998, by about 0.5C, and higher than 2016 by about 0.4C.

No only that, it also had by far the best data density.

Chris Hanley
January 2, 2019 7:24 pm

“You can say I don’t believe in gravity. But if you step off the cliff you are going down. So we can say I don’t believe climate is changing, but it is based on science …” – Katherine Hayhoe, co-author of the 4th National Climate Assessment Report.
The ‘stepping off a cliff’ analogy is false, it is not high confidence based science, it’s a certainty based on empirical evidence.
What an idiotic comparison to be in a supposedly considered scientific report.

J Mac
Reply to  Chris Hanley
January 2, 2019 7:29 pm


R Shearer
Reply to  J Mac
January 2, 2019 8:08 pm

Yes, let’s consider what we know about a fundamental constant of gravity on earth (acceralation due to gravity taken from Wiki):

Gravity on the Earth’s surface varies by around 0.7%, from 9.7639 m/s2 on the Nevado Huascarán mountain in Peru to 9.8337 m/s2 at the surface of the Arctic Ocean.[5] In large cities, it ranges from 9.7760[6] in Kuala Lumpur, Mexico City, and Singapore to 9.825 in Oslo and Helsinki.

Contrast that with what we know about a fundamental constant related to climate change, the transient climate sensitivity. According to IPCC 3rd assessment, it’s likely to be in the range of 1.5 to 4.5. That range covers a difference of 300% and it’s worse than that. Climate sensitivity might be zero or even negative.

Greg Cavanagh
Reply to  R Shearer
January 2, 2019 8:25 pm

It sounds like what they’re saying is: We have high confidence that no matter what the final climate sensitivity figure turns out to be, it’s humans that caused it.

Tom in Florida
Reply to  Greg Cavanagh
January 3, 2019 4:54 am

or perhaps: that no matter what the final climate sensitivity figure turns out to be, we have high confidence that we will say it’s humans that caused it.

Steve Reddish
Reply to  R Shearer
January 3, 2019 9:59 am

R Shearer,

My rough calculation of the range in the measured force of G at any one place gives a difference of .001% – .0005%, depending upon method of rounding last digit. Contrast that to the 300% range you noted.

I think the IPCC believes 1.5 is very close to the actual value. They keep the 1.5 in their estimate of sensitivity just so they can claim they were being truthful when the actual value becomes an accepted fact. They keep the 4.5 value in the meantime just so they can make scary projections.


Chris Hanley
Reply to  Chris Hanley
January 2, 2019 7:37 pm

Thanks to Issac Newton people have learned not to step off cliffs

joe - the non climate scientist
Reply to  Chris Hanley
January 3, 2019 8:01 am

I would think humans learned not to step off cliffs long before newton

Clyde Spencer
Reply to  Chris Hanley
January 2, 2019 7:48 pm

Some would have us believe that perception is reality. However, Hayhoe’s remark illustrates a pseudo-reality that has a heavy penalty for ignoring reality.

As Curry remarks, “Climate change is a very serious issue — depending on your perspective, there will be much future loss and damage from either climate change itself or from the policies designed to prevent climate change.” Therefore, I’d suggest that we should be working in the 2 to 3 sigma range of confidence if we are going to make serious decisions!

Doug Procyor
January 2, 2019 7:27 pm

I have been an exploration geologist for many years. I have noted that proposed projects generate more excitement and acceptanxe “we’ve really got something!” the bigger they are. The longer they are in progress, the cleaner the maps and graphs get, and the PowerPoint slides, both simpler and more assertive. The confidence goes up visibly, as does the numbers in attendance at a presentation.

When the project proceeds beyond the technical to the managerial, data falls away. A technical study become cartoonish. Risk decreases and benefit increases with each level up. There is even an improvement in the clothing/grooming im the upward march.

But …. what happens when there is failure, the statistically likely outcome? A frown and silence at the top, and absulute astonishment at the “created” source.

The greatest shock of reality not meeting expectations – and external fault searching – is at the base because everybody mistakes other people’s excitement of porential shared glory as evidence of their rightness.

January 2, 2019 7:37 pm

if you want to analyze marketing, don’t be puzzled if it does not conform to scientific criteria.

Marketing has its own law. The Law of Credible Affirmation (or its complement: the Law of Plausible Deniability).

In Marketingm, Science – or the appearance of Science – is merely there to confer credibility.

The target market does not understand science.

But it is impressed by Big Words that it does not understand, Especially if it thinks it is smarter than average, To admit it Doesn’t Understand the Big Words, is – well – humiliating.

I say this to avoid the necessity of going through IPCC reports with a fine toothcomb to establish that the summary (marketing) is unscientific.

I mean why would it not be?

Its marketing.

Reply to  Leo Smith
January 2, 2019 8:44 pm

This is similar to my mother’s law of economics, perhaps a corollary to supply and demand. “The marketplace raises prices to the level that it can get away with. ” Climate science seems to follow a similar rule- “raise the hyperbole until it breaks”.

Geoff Sherrington
Reply to  Leo Smith
January 2, 2019 11:41 pm

Yes Leo,
Here in Aust we have commercial for a sparkling, bottled water, a costly import from a spring in Europe, marketed as ‘chemical free’ and ‘carbon neutral”.
Incredibly stupid follow the money stuff.
What should be more hated by greens than a product designed to increase atmospheric CO2, when it could sell with none.

When I was a child, toothpaste started being marketed as containing chlorophyll, with scarce a reason why this might be good.
The riposte:
“Why reeks the goat on yonder hill
Who dotes so much on chlorophyll”.
(Attr: Alan Feingold, M.D. Decatur, Ga.) Geoff

Reply to  Leo Smith
January 3, 2019 4:40 am

I was going to call it Theology, maybe Marketing is more appropriate, but here is what philosopher Roger Scruton wrote about theology:

“The purpose of theology has been to generate experts about a topic on which there are no experts, namely God. Built into every version of theology are foregone conclusions of a faith: conclusions that are not to be questioned but only surrounded with fictitious scholarship and secured against disproof.”

Tom Abbott
January 2, 2019 7:39 pm

Here is a comparison of the Hansen 1999 US Surface Temperature chart with a bogus, bastardized Hockey Stick chart (in this case, Hockey Stick chart refers to any chart that has “disappeared” the 1930’s warm period and the 1998 El Nino warm period).:

As you can see, the Hansen 1999 US surface temperature chart is on the left and the bogus, bastardized NASA Hockey Stick chart is on the right.

The Climate Change Charlatans want us to believe that the US has a completely different temperature profile that the rest of the world.

The bogus, bastardized Hockey Stick chart depicts an almost steady climbing upward curve to its temperature profile, thus giving the impression that the temperatures are getting hotter and hotter and hotter and have been doing so for decades.

OTOH, the Hansen 1999 US surface temperature chart shows the temperature profile warming from 1910 to 1940, and then cooling from 1940 to 1980, where the temperatures reached about the same level as the cool temperatures of 1910, and then the temperature profile shows warming from 1980 to the present, with the highest temperature recorded during that period being Feb. 2016, which was 0.4C *cooler* than 1934. We are actually in a temperature downtrend. There is no unprecedented warm today.

The Hansen 1999 profile shows a world where there is no unprecedented warming and there is no requirement for CO2 to get us to where we are today.

Now those who want to promote the Hockey Stick will claim that the US Hansen chart does not represent the whole world, whereas their bogus, bastardized Hockey Stick chart does represent the whole world. The only problem with that argument is when you look at unmodified temperature charts from around the world and in both hemispheres you see the same temperature profile as the one the Hansen 1999 chart displays: The 1930’s are as warm or warmer than subsequent years.

If the Alarmist were to acknowledge this, their whole CAGW fantasy would go POOF! That’s why they created the bogus, bastardized Hockey Stick chart in the first place, so they could fool everyone into thinking we were in unprecedented territory when it comes to atmospheric temperatures. They are liars, and the Hockey Stick is their lie.

richard verney
Reply to  Tom Abbott
January 3, 2019 5:19 am

Quite so, and it is material that this is the best sampled country having the most historic record. I have often made the point that the warmists need to explain what geographical and/or topographical features of the US would render it an outlier, and not representative of temperatures in the latitude band 25 deg to 50 deg North. The US is a large area of land, particularly by Northern Hemisphere standards, and has a good mix of geographical features, mountains, plains, valleys, towns, cities, lakes, rivers, deserts, forests etc and has borders with oceans but not particularly and uniquely subject to any particular current.

Further, on your point, if you look on the NOAA web site it displays both the unadjusted and adjusted temperatures for Greenland and for Iceland and the unadjusted temperatures show the late 1930s/1940 to be the warmist period. In Greenland only 2010 came close to the earlier high (2010 might even have slightly exceeded the earlier high, but temps since 2010 have fallen in Greenland).

Reply to  Tom Abbott
January 3, 2019 6:15 am

How does a 1999 chart say anything about 2016? And isn’t one showing a peak in the 1930s specific to the US, since ones for the whole world, even ones a lot older than 1999, show a peak centered at or a couple years after 1940 with less cooling in the few decades afterwards?

Tom Abbott
Reply to  Donald L. Klipstein
January 3, 2019 9:38 am

Donald wrote: “How does a 1999 chart say anything about 2016?”

Well, the Hansen 1999 US surface temperature chart shows the relationship between 1934 and 1998, where 1934 is 0.5C warmer than 1998, which makes 1934, 0.4C warmer than 2016, when 2016 is compared to 1998 on the UAH satellite chart. The Hansen 1999 chart covers some of the same time period as the UAH satellites cover.

Donald wrote: “And isn’t one showing a peak in the 1930s specific to the US, since ones for the whole world, even ones a lot older than 1999, show a peak centered at or a couple years after 1940 with less cooling in the few decades afterwards?”

None of the older surface temperature charts look exactly the same. There is definitely variation. But whether the peak warmth is in the middle 1930’s or the early 1940’s, what is true of all of them is that period of time was as warm or warmer than subsequent years.

Which means we are not currently experiencing unprecedented warming. It was this warm back in the 1930’s. Which means there is no need to invoke CO2 as a driver of the climate, the climate already had all the drive it needed without CO2 in the 1930’s.

All the older unmodified surface temperature charts show that we are not experiencing unprecedented warming today.

Look at some of the TMAX charts in this recent WUWT post. They show we are not experiencing unprecedented warming today.

Btw, none of the unmodified surface temperature charts from around the world look anything like the bogus, bastardized “hotter and hotter” Hockey Stick charts. Hockey Stick Charts are The Big Lie.

paul courtney
Reply to  Donald L. Klipstein
January 4, 2019 10:45 am

Is Mr. Klipstein trying to play the fool? He spends enough time at this site to know the answer to both questions.

Chris Hanley
January 2, 2019 7:40 pm

Sorry Isaac.

Ronald Ginzler
January 2, 2019 7:40 pm

“Data are still sparse in the tropics, SH and over oceans.” So, over 80% of Earth. So let’s get more data. Get them boys and gals and gender neutrals off the computers and measuring real stuff. When science degenerates to thinking about science, calculating “confidence levels,” i. e., arm waving, it ain’t science. So let’s stop blowing wind up our skirts, or trousers, or whatever them gender neutrals wear. This post weren’t intended to offend nobody.

Jaap Titulaer
Reply to  Ronald Ginzler
January 3, 2019 6:52 am

“So let’s get more data. ”

That data already exists. More than 100 peer reviewed studies, covering all over the world (in stark contrast to Mann or Pages2k (2013 or 2017), who mostly depend on a few NA or NH data points, weighted more than 100 times in case of a single NA tree, using updide down data, or using data clearly just showing the effect if recent dambuilding).
See for an overview of a constantly updated collection:

But the fake scientists simply ignore all of that, they act as if the data does not exist (it does), or is not peer reviewed or published (it is) or is merely local when in fact we have dozens of studies for each continent or hemisphere.

And the data all gives the same answer: the MWP fid ecists, was global and was at least as warm as today if not clearly warmer (as already expected for Europe and China due to historic records).

John F. Hultquist
January 2, 2019 7:48 pm

Regarding: Confidence just below the small yellow table:

Medium Confidence = About 5 out of 10 chance

Many years ago – before personal computers, the internet, and cell phones – kids found ways to entertain themselves.
One thing was to dare someone to do something, for example jump of a bridge railing into a river. Would you get hurt, Medium Confidence?
Off the railing we went.
Another dare involved a finger and a mechanical cigarette lighter, Zippo comes to mind, as we lived less than 100 miles away from Bradford.
The Zippo was said to light every time.
Very high confidence = at least 9 out of 10.
So the dare was, ‘stick out your finger, and spin the wheel’.
If it doesn’t light, off goes your finger.
No one ever took that dare. 9 out of 10 is not Very High Confidence.

Anyway, thanks to Judith and others for reading these reports.

Steve Reddish
Reply to  John F. Hultquist
January 3, 2019 11:08 am

9 out of 10 means you were sure to loose a finger before testing every finger on both hands.


January 2, 2019 7:50 pm

Judith Curry does a good job of identifying the obfuscation that permeates the AGW narrative and it’s always a moving target. It’s propaganda, not science.

Linda Goodman
January 2, 2019 7:52 pm

Rules For Radicals rule #1:
“Power is not only what you have but what the enemy thinks you have.”

Greg Cavanagh
Reply to  Linda Goodman
January 2, 2019 8:32 pm

Sounds very much like Sun Tzu, The Art of War.

a right-minded lefty
Reply to  Linda Goodman
January 3, 2019 2:08 am

Yes, one of the oldest war tactics in the book.

And unfortunately scientific argumentation is not as powerful as sophistry and emotional manipulation when waging a Perception Management war. Sigh.

January 2, 2019 7:52 pm

Judith Curry does an excellent job of identifying the obfuscation in the AGW narrative. It’s all about propaganda and not science.

January 2, 2019 7:59 pm

For ‘medium’ and ‘low’ you could add the following descriptions.

Institutionalized data (gatekeeping) and institutionalized bias evident (with funding often tied to a particular view or outcome), data or code not widely available, with conclusions found or likely to be subject to confirmation and other biases. Evidence of research and outcomes being politicized, with links to activism, and retraction of papers in the field.

Smart Rock
January 2, 2019 8:00 pm

Making an epistemological analysis is a very powerful way of appraising any piece of science, and Dr. Curry has done her usual meticulous study of this NCA4.

I’ve come to the conclusion that most people, and probably a majority of scientists too, have difficulty in distinguishing between:
&bull what they know to be true (based on overwhelming evidence and direct observation)
&bull what they think is true (based on some evidence)
&bull what they want to be true because it aligns with their beliefs
&bull what they have decided is true before they even started thinking about it

I submit that most of the “knowledge” of current climate science belongs in the last category

There is another category, that’s really outside epistemology:
&bull what they pretend is true because if they don’t say it, they may lose their jobs and/or get no more research grants.

HD Hoese
January 2, 2019 8:10 pm

I have been reading vol II ( on things I thought I understood, but when I ran into this, well it don’t matter and they invoke the precautionary principle just in case.
(“Furthermore, ocean ecosystems are becoming increasingly NOVEL (CAPS MINE), meaning that knowledge of current ecosystems will be a less reliable guide for future decision-making (Ch. 28: Adaptation, KM 2)”) from Chapter 9 KM1, Ocean Ecosystems.

In vol I, this is not overconfidence, from 13.5.3 Primary Productivity (“The effect of the multiple physical factors on NPP is complex and leads to model uncertainties.”) except they seem to believe that NPP (net primary production) is going to decrease despite increases in nutrients. I think their problem overall is negativity because the evidence they cite suggests a more measured conclusion, could be up, could be down, could be all over the place, but they worry about decreases in the last sentence. I suppose that uncertain negativity could lead to overconfidence. They did have government on their back about this.

You have a tough job, from what I have seen in volume II, it gets worse.

January 2, 2019 8:22 pm

“Confidence” is no more scientific than “consensus”. It’s another meaningless phrase warmists use to persuade the gullible that their claims are legitimate.

Proxy climate data is so imprecise at measuring temperature that the only meaningful conclusion that can be derived from it is a low-resolution view of long-term trends. It is impossible to correlate proxy data and measured temperatures with any useful specificity, despite the assurances of Mann et al.

Greg Cavanagh
Reply to  stinkerp
January 2, 2019 8:37 pm

noun: confidence
1. the feeling or belief that one can have faith in or rely on someone or something.

I have confidence in my boss. That does not mean that things will continue as they are, or that he has my best interest at heart. In fact; my confidence could be entirely misplaced, or without merit whatsoever.

Confidence says more about the person who is confident, than it does about the subject.

a right-minded lefty
Reply to  Greg Cavanagh
January 3, 2019 12:42 am

Yes, I would say you gentlemen have nailed it.

“Confidence says more about the person who is confident, than it does about the subject.” -GC

“Confidence is a red herring designed to obscure the reality that the scientific method requires us to downgrade the influence of CO2 on climate change because it makes predictions (and projections), worse, not better.” -BCBill

And as astronaut Walter Cunningham concisely explained at 45:01 of the video “25 Nasa Scientists Question the Sanity of the Global Warmists”:

“…These true believers in humans controlling the Earth’s temperature cannot be reasoned out of their position. It was not reason that got them there in the first place. It was emotion and politics…”

So sophistry about “confidence” has no place in scientific debate but it is Standard Operating Procedure in a Perception Management game.

a right-minded lefty
Reply to  a right-minded lefty
January 3, 2019 1:01 am

Excuse me Stinkerp, I’d missed that you were the one to have initiated this line of reasoning here.

“Confidence” is no more scientific than “consensus”. It’s another meaningless phrase warmists use to persuade the gullible that their claims are legitimate.”

Indeed! Well spoken!

Reply to  stinkerp
January 2, 2019 10:37 pm

This is a good point. Confidence is not really a criterion for selecting the better hypethesis. The most important test for selecting the better hypothesis is determining which one results in the better predictions. So far a straight line projection of historical temperature gives a better prediction than models which attribute significant effect to CO2. Scientific protocol requires that we accept the simplest and best model, i.e., the one that gives the best prediction with the least variables. Confidence is a red herring designed to obscure the reality that the scientific method requires us to downgrade the influence of CO2 on climate change because it makes predictions (and projections), worse, not better. Confidence, especially some nebulous, artsy fartsy kind of confidence has no place in a scientific discussion. Show the projections. If the conclusions are not obvious then science has nothing further to say until the data are improved.

AGW is not Science
Reply to  stinkerp
January 3, 2019 7:55 am

“Consensus” is antithetical to science. The mere fact that their “high confidence” and “very high confidence” definitions BOTH include “consensus” as part of what defines them tells you that their assertions of “confidence” have nothing to do with “science.”

January 2, 2019 8:32 pm

Tony Heller has covered the NCA in a three video series and just tears it apart.

Dr. S. Jeevananda Reddy
January 2, 2019 8:39 pm

With all the respect, I want ask the author of the report, what exactly you wanted to convey to the readers?


Rick C PE
January 2, 2019 10:08 pm

Irving Lagmuir coined the term Pathological Science in 1953 and defined it as:

Pathological science, as defined by Langmuir, is a psychological process in which a scientist, originally conforming to the scientific method, unconsciously veers from that method, and begins a pathological process of wishful data interpretation (see the observer-expectancy effect and cognitive bias). Some characteristics of pathological science are:

– The maximum effect that is observed is produced by a causative agent of barely detectable intensity, and the magnitude of the effect is substantially independent of the intensity of the cause.
– The effect is of a magnitude that remains close to the limit of detectability, or many measurements are necessary because of the very low statistical significance of the results.
– There are claims of great accuracy.
– Fantastic theories contrary to experience are suggested.
– Criticisms are met by ad hoc excuses.
– The ratio of supporters to critics rises and then falls gradually to oblivion.

Langmuir never intended the term to be rigorously defined; it was simply the title of his talk on some examples of “weird science”. As with any attempt to define the scientific endeavor, examples and counterexamples can always be found.

(from Wikipedia)

I would suggest that the IPCC process ticks all the boxes.

Reply to  Rick C PE
January 2, 2019 10:40 pm


January 2, 2019 10:20 pm

“You can say I don’t believe in gravity. But if you step off the cliff you are going down.
Climate change is equivalent to gravity changing. Unless we give up fossil fuels gravity will change causing disaster all over the world.

Science wants us to give something today of enormous proven benefit based on a risk that may or may not be real, many years in the future.

No allowance is given for human ingenuity to solve this problem using fossil fuels and the likelihood that we would be giving up the very thing we need to solve the problem.

Reply to  Ferdberple
January 2, 2019 10:49 pm

Very good. For as long as we can tell, gravity has pulled us down and climate has varied but self corrects to within a fairly narrow range. Based on a hypothesis which offers no credible feedback mechanism to amplify a minor effect from CO2, we are supposed to ignore billions of years of evidence. AGW in fact requires us to believe that if we step off a cliff, we will fall up.

January 3, 2019 1:57 am

Jamal Munshi has recently offered this paper:

“Circular reasoning is a logical fallacy in which research design and methodology as well as the interpretation of the data subsume the finding. This fallacy can be found in published research and it is more common in research areas such as archaeology, finance, economics, and climate change where the data are mostly time series of historical field data with no possibility for experimental verification of causation.

In biased research of this kind, researchers do not objectively seek the truth, whatever it may turn out to be, but rather seek to prove the truth of what they already know to be true or what needs to be true to support activism for a noble cause (Nickerson, 1998). Such confirmation bias or yearning (Finkelstein, 2011) is found in research areas related to religion or to activism.

Confirmation bias is thought to play a role in climate change particularly since climate science provides the rationale for environmental activism and the noble cause of saving humanity or perhaps the planet from climate cataclysm (Kaptchuk, 2003) (Nicholls, 1999).

This hidden hand of activism plays a role in the way climate research is carried out and in the way findings are interpreted and disseminated (Cooper, 2006) (Britt, 2001) (Bless, 2006) (Juhl, 2007) (Watkins, 2007) (VonStorch, 1995) (Enright, 1989) (Britt, 2001) (Hodges, 1992) (Curry, 2006).”

In 1999, there was a series of seminars in Europe focusing on “Uncertainty in Climate Models”, known as the ECLAT series, “Representing Uncertainty in Climate Change Scenarios and Impact Studies” published by the Climatic Research Unit, University of East Anglia. Very many conclusions on uncertainty were drawn from the seminars. I quote from the introduction here:

“even with perfect models and unlimited computing power, for a given forcing scenario, a range of future climates will always be simulated. It is for this reason that the Intergovernmental Panel on Climate Change (IPCC) have always adopted the term ‘projection’.”

Here are a few more statements from the ECLAT series, (not my quote marks within the text):

“Projecting the future state(s) of the world with respect to demographic, economic, social, and technological developments at a time scale consistent with climate change projections is a daunting task, some even consider as straightforward impossible.

Over a century time scale, current states and trends simply cannot be extrapolated. The only certainty is that the future will not be just more of the same of today, but will entail numerous surprises, novelties and discontinuities.

“The probability of occurrence of long-term trends is inversely proportional to the ‘expert’ consensus.”

Excessive self-cite and “benchmarking” of modeling studies to existing scenarios creates the danger of artificially constructing “expert consensus”.

In the presence of multi-decadal climate variability a thirty-year mean may provide an incorrect estimate of the longer-term average climate.”

Uncertainty has now been transformed into “increasing scientific evidence tells us” without ever saying what that evidence is.

Rod Evans
January 3, 2019 2:01 am

I have reviewed my confidence level in climate change.
I am 100% confident climate changes.
I am 97% confident not all journalists know this.
I am 100% confident research into “Mann” Changing historical Climate is justified.
I am 95% confidant snow fall in North America is causing people to question Gore-bull warming.
Happy New Year to all, might go skiing later…

E J Zuiderwijk
January 3, 2019 3:40 am

The comparison between the theory of Gravity and the AGW muddle is a profoundly dishonnest one. It purpose is simple: you don’t doubt the knowledge about gravity, therefore you ought to accept ‘climate science’ as well. Implicitly it claims that the science of gravity ‘is settled’. That is rubbish, science is never settled, and that applies also to gravity. There are at least three research groups worldwide who do experiments on gravity at very small distances and atrophysicists have just started to explore the realm of gravitational waves. Why? Because they want to find out if there are aspects to gravity which we have not yet discovered. Science is never settled, and I would not bet against the possibility that two centuries from now there is a description of gravity even more profound than Einstein’s.

Johann Wundersamer
January 3, 2019 3:47 am
Johann Wundersamer
January 3, 2019 4:04 am

“You can say I don’t believe in gravity. But if you step off the cliff you are going down. So we can say I don’t believe climate is changing, but it is based on science.” – Katherine Hayhoe,


science – or first steps in life?

Steve O
January 3, 2019 4:39 am

“‘High confidence’ is described as ‘Moderate evidence, medium consensus.’ The words ‘moderate’ and ‘medium’ sound like ‘medium confidence’ to me… Such misleading terminology contributes to misleading overconfidence in the conclusions'”

This is called hitting the nail on the head and burying it flat in a single blow. The PURPOSE of assigning a specific but misleading definition is to mislead the public, who will read the words quoted in an article and will assume they mean what they generally mean when they are used in conversation.

Peta of Newark
January 3, 2019 5:03 am

‘Overconfidence’ is the *only* word you need from this.

And where else do you see ‘overconfident’ folks if not in pubs, bars and drunken parties?

In part because they are in a large social gathering (The Consensus) but mainly because their brains are chemically depressed – their inhibitory system has been closed down.
The process starts at with breakfast (cereals, toast, jam, jelly, sugar) and when that barrage of junkfood wears off, is re-reinforced with mid-morning snacks of Mars Bars, doughnuts, biscuits, sweetened tea/coffee.
That wears off by lunchtime so another bellyful of junk is taken aboard (what do you have for lunch)

This is a much bigger bellyful than normal so by 15:00 in the afternoon, almost everyone is effectively asleep.
What sort of science are they gonna be doing?

They wake at 15:30 into a dehydration-induced hangover and their heads are full of ‘Oh God I can’t wait to get home’
For what?
Another epic belly full of nutrient free mush washed down with beer, wine and whiskey and in the resulting half-asleep state, they proceed to watch hordes of dysfunctional characters acting out bizarre & surreal situations on Trash TV
Doing what? Slagging each other off. Throwing around wild & exaggerated accusations. Being world-saving Super Heroes.

(Some folks have realised all this and come up with the term ‘Unreasonable Behaviour’. You may have married one of them. And all that ‘food’ is going into a machine that can happily exist, evolved to exist in fact, on a single meal every 24 or 48 hours. Utterly crazy. All the stuff we now eat has stopped being ‘food’. It is a drug.)

Do ANY of those things seem familiar to what Warmists do or wish upon others?
Lets play the game here too – Skeptics also.

The chemically disabled brain loses track of what is real and what is not – it creates fake memories, false beliefs and dysfunctional neural pathways.
It is also lazy, it panics easily, is belligerent and readily gets angry.
It cannot ‘think’ its way out of everyday humdrum problems, let alone huge things like Climate and once it has set its path, it will defend that with great vigour.
Thinking is hard work.
Hence we see endless appeals to the authority of The Computer.

The barrage of depressant chemicals taken aboard throughout the day results in their consumer falling unconscious when they ‘hit the sack’.
NOT asleep. Effectively dead.
Hence why and when aroused 7, 8 or 9 hours later, the chemically deranged brain reaches for 2 things.
Coffee – to wake itself up. (If that’s not bizarre enough after so much ‘sleep’)
And sugar. Exactly similar to the good-old-days, when it reached for a cigarette.
Both do the same thing -creation of a (false) state of happiness and well being and so the new day follows the same path as the previous one – a constant state of semi-sleep, belligerence, (dehydration induced) grumpiness and heightened startle response.
All sensible work ceases as the brain endlessly worries about when its next dose of Dopamine is coming from.

THAT is the real problem.
All the blog posts in the world, all the best reasoned thinking, all the best appeasement and niceness is NOT going to change the mind or behaviour of the chronically chemically depressed brain.
If it does have any effect, it will only reinforce the thinking of the chemically damaged mind and if you persistently push the point, will result in a fight.
A proper fight where folks get hurt.

I’m actually in front of a TV showing ‘news’ and The Main Story this morning is exactly what I’m raving about here:
The Obesity Crisis – the significant side effect of all that drug taking, the sugar-induced dehydration and the trashed sleep. Bizarrely, it was actually predicted to happen. (50 years ago??)
Not HOW it was going to happen, but that it WOULD happen. Note the difference.

No matter, A New Tax will solve it I’m sure.
Oooh, there’s some refugees climbing out of an inflatable boat on the telly now – wonder what THAT is all about? Come to visit the Land of Milk and Honey I expect.
Apart from the GHGE, how wrong is it possible to be?

January 3, 2019 5:24 am

The NCA4 is largely BS (High confidence).

michael hart
January 3, 2019 5:24 am

There is a fifth type of overconfidence:

January 3, 2019 5:49 am

Does this need to be argued in as much detail? Real sceptical scientists are not the problem or the audience here. They can test this carefully constructed deceit and understand what is fact and what is guessed, what is deceitful assertion and what is honest science in the probablistic sense Feynman sense. No policy maker would ever read such a level of detail, never mind filter the implications, and a lot of statistical climate “scientists” would get (more) lost. They can only follow the simplest truths, that they knew when designing the models to test them. So are there any simple measurable facts to to nail conclusions to and test IPCC assertions against?

1. Seems from your scrutiny that the IPCC base their history of the holocene on the one set of much manipulated, extreme and ultimately unprovable assumptions of Mann et als tree and consequential smoke rings. MOre interesting, although they claim support from other temperature series they don’t actually produce or refer to. So they are relying on an outlier and he mean/median. There ARE others papers with series that show different temperature profiles from different proxy data. The IPCC picked an outlier study, and implied support that doesn’t exist. That is deceitful. The facts support the actual deceit. See graph.

2. FACT: The predictions of doom do not reflect measured reality, so the models are wrong. Probably because the models programme a weak, diminishing logarthmically in power, and ultimately unlikely cause to be dominant, rather than seek the answer. The results can offer no scientific proof, show little measured correlation, are are based on various unprovable guesses input by the modellers, not facts. The most extreme and disparate model outputs versus actual measurements are used as the basis for demanding a response to an unproven in fact cause. Why? Could it be the money?

Why don’t politicians compare the IPCC forecasts with measured reality from real satellite data? Perhaps no one cares to show them? Could it be the money, those skimmimg the cash flow of snake oil cures don’t want to know?

3. Why are the IPCC forecasts NOT validated by the actual data? Which should we believe?The observations or the guesses for reward?

4. Statistical models do not require or prove any physical laws. Climate models are made up for reward by University’s VR “climate scientist” computer theorists to support the client’s particular assumption about CO2 – and simply show statistical correlation by number wrangling. Here is how that work matches reality on the climate facts that anyone can plot for themselves:

comment image?dl=0

Clearly the models are wrong.

5. Why the over forecast? Could this IPCC statement regarding its models be a reason?

“The climate system is a coupled non-linear chaotic system, and therefore the long-term prediction of future climate states is not possible.” IPCC:


More Technical bit:
A1 Simple fact of modelling: If you guess a larger sensitivity due to CO2 in history to create a model that correlates with reality in “real times”, and also artificially limit the variables you consider and the sensitivities applied to other variables to get that result, then extrapolating such a model into the future will amplify those errors, e.g. it will be wrong, doesn’t matter who designed it. Obs. I suggest that is as complicated as an non modeller needs to go.

A2 The climate scientist’s deceit is overt, as illustrated above and elsewhere, and hence undeniable (honestly). The real science denial for a fast buck academic statistical modelling industry that the UN created to drive this multi $Trillion deceit is easy to expose, but their pseudo science, as with any pseudo science, is always unprovable either way. That’s why they use it.

A3 Follow the money. The much larger subsidy fraud that depends on belief in “climate change caused by CO2” is wholly provable, and the absolute deceit regarding the deliverability of adeqaute , sustainable, affordable renewable energy (subsidy) industry that can replace fossil enregy (that isn’t renewable nuclear energy) is easy to demonstrate.

But who needs numbers, when you can make Trillions from averting a non-problem – if you can sell this bullshit to fearful citizens as a religion? Never mind the climate, follow the money. Unless you are a major manufacturer and not a populist regime, then you create the energy you need by the methods that work, as in SE Asia, China, India. Because nothing else works.

So this scam is really only working where we have exported the manufacture of our stuff to those who need to emit CO2 or build nuclear to make the energy to make our stuff, and no one left in the de indusrialised world understands how things work, except making a fast buck.

That’s what I think. And can also prove.

Gary Grubbs
January 3, 2019 5:49 am

Some commentary on the overconfidence issue:

I think, to a point, the confidence scale that is used above and has worked it’s way into reports is indicative of what I call “Societal Inflation”. We do everything bigger etc. as compared to our past. Examples include drink, pizza, fries etc. It used to be, when I was a small lad, that you had small and large. Then medium was added. Over time that criteria has been replaced with medium, large, extra-large, super sized. Small is gone from our sizing criteria. Pinball scoring (This is where I first observed this phenomenon), used to be in the hundreds, then to thousands and now into the millions. So the elevation of the confidence levels is reflective of that.

As an engineer, I will verify what several of the engineers stated above. We would loose out jobs if we did this type of analysis.

Notice that almost none of the predictions stated by the alarmists have any confidence level associated with them. And most of the predictions have a confidence level of almost zero. They are just boldly stated and we move on. The prediction does not occur and we yawn and continue our lives.

The original hockey stick graph showed runaway temperatures in the early 2000s. Media source after media source copied the graph and presented it without reference to sources, confidence level etc. The confidence level for that graph had to be low, but is was not stated or inferred that it was. It looked good to start a movement.

I think another thing that enters into the confidence ratings is the current mentality of so many people, especially young people. They know because they are _____________. Therefore it must be true. Fill in the blank with special, smart, virtuous, etc. It is emotionalism at work. It replaces wisdom, life experiences, facts, technical analyses, and debate.

January 3, 2019 6:15 am

By having our guiding hand on a colourless odourless trace gas in the atmosphere that feeds plants we have our hand on the thermostat dial that controls the temperature of the globe. That’s not overconfidence but hubris and a whole new category again.

January 3, 2019 6:22 am

One thing about NCA4 having higher confidence than AR5 that the past few decades were the warmest in the past 1700 years: The AR5 statement is about 1983-2012. If one considers a start year a few years after 1983 and an end year a few years after 2012, one finds global temperature significantly warmer than it was over 1983-2012.

Bruce Cobb
January 3, 2019 6:28 am

Well, it’s all just a big confidence game, innit. The Climate Hucksters look on people as stupid sheeple, ready to be fleeced.

Dr Deanster
January 3, 2019 6:54 am

What truly needs to be conducted and published is an assessment of each piece of evidence. The “confidence measure” should not rise above the confidence associated with each piece of evidence. For example, Mann 2008 needs to include all the opposing material associated with it, and a final conclusion made regarding the confidence in the individual paper as judged by uninterested parties. If both Mann and the other paper bring with them medium confidence, then the overall confidence in the finding should not rise above medium confidence. …. JMO.

AGW is not Science
January 3, 2019 7:34 am

“Inconclusive evidence (limited sources, extrapolations, inconsistent findings, poor documentation and/or methods not tested, etc.) disagreement or lack of opinions among experts”

Sounds like a perfect description of what is laughingly called “climate science” to me. So the whole “field” of so-called “climate science” gets a “Low Confidence” rating by their own definition.

January 3, 2019 7:44 am

When a Warmunist asks me, “Do you believe in gravity?” I reply, “Of course, but I also believe gravity has not gotten any stronger in the last 100 years nor will it turn my children and grandchildren into pancake people.”

Kevin kilty
January 3, 2019 7:59 am

I am rather surprised by this statement

“Assessment of confidence based on evidence and agreement, including short description of nature of evidence and level of agreement
: There is high confidence for current temperatures to be higher than they have been in at least 1,700 years and perhaps much longer.

It is an ex cathedra statement, nothing more. It presents no evidence for confidence, and I think nothing more demonstrates overconfidence than ex cathedra argumentation.

By the way, Dr. Curry again speaks of a “red team” as a way to inject more rationality into this process. However, won’t members of a red team have many of the same limitations of the “green” team (or whatever the other color is)? Since the skeptical bench is a bit thin and not very deep, won’t some of the red team be unenthusiastic greens? How can we have confidence of a reasonably, or better yet competent, adversarial debate?

John Endicott
Reply to  Kevin kilty
January 3, 2019 9:01 am
January 3, 2019 8:21 am

Thank you Judith, for the excellent analysis of how they label NCA4 findings with confidence levels. The NCA4 seems to miss some of the qualities found in the AR reports. I think IPCC does a superb job in the scientific AR reports though.

Personally, I think the most interesting part in the NCA4 is the estimates of direct economic damage described in figure 29.3. The economic damage reflects most of the other problems and is therefore usually the single most important metric.

The figure says that the damage in the higher scenario (i.e. the worst case) will amount to between 2% and 11% if GDP in 2090.

My take on this is that it seems to be a rather small problem that the economy become between 2 and 11 percent smaller than it could have become in 71 years. In that time the GDP will probably have grown several hundred percent, and nobody will notice that it has not grown as much as it could.


Buck Wheaton
January 3, 2019 8:52 am

This is not “epistemic overconfidence”, this is the manifestation of woke progressive-ism on a grand scale. Ideology determines truth, truth become a tool to move the ideological agenda, the agenda is to advance the ideology. The meaning of words, Truth and thus the scientific method are all subverted to become malleable and plastic. All policy advocacy converges far more towards creating the perfect society and by those means to create the Perfect Socialist Man than any other factor.

Marx, in Das Kapital, originally looked to economic reordering to reshape human nature. When his ideology caused the deaths of 100 million people, post-modern Marxists redesigned the vision to use “social justice” and “diversity” as their transformative mechanism. Environmentalism and “climate change” are closely related. But the end goal is the same. When anyone refuses to go along, or refutes it in any way, they must be destroyed by any means necessary because they are holding up humanity’s transformation and Utopia itself.

John Endicott
January 3, 2019 9:20 am

“You can say I don’t believe in gravity. But if you step off the cliff you are going down. So we can say I don’t believe climate is changing, but it is based on science.” – Katherine Hayhoe, co-author of the 4th National Climate Assessment Report.

false equivalence.

First off, no one doesn’t believe climate is changing. Climate has been changing ever since there’s been a climate (long before man every came along) and will continue change (even long after man is long gone from the scene). so that’s a strawman to go with the false equivalence.

Secondly, the science of gravity is scientific. Science, you see, is predictive. You can predict how fast an object will fall off that cliff and when it will hit the ground (heck when I was a student in High school we performed such calculations as one of our class projects). AGW aka CAGW aka man-made climate change is not predictive (or rather it’s failed in every testable prediction it’s tried to make) therefore it’s not scientific. The arctic is not ice free (despite the prediction of “climate change” proponents), Hurricanes have not increased in number and severity (despite the prediction of “climate change” proponents), the West Side Highway is not underwater (despite the prediction of “climate change” proponents), etc. There isn’t one testable prediction they’ve gotten “right” so far.

January 3, 2019 9:26 am

Thank you for the always attempting to translate difficult science, philosophy, logic, quality of evidence, et al for the interested, somewhat capable public.
As a former electric utility engineer and lifetime science fan, I offer some additional perspectives: 1. Just as confidence in science is not generally understood, the offered solutions for climate change are also highly questionable from a both effects and economic costs (vs effects of warming and damage). 2. Science in general is highly respected and perhaps too easily and quickly trusted by the general public. Scientific claims and sources are trusted almost religiously-even within the “capable of understanding” science and related communities. 3. The general public and associated folks who could follow along and support or change their beliefs are too busy with life to spend time on issues from even “trusted” sources. Policy is made by the unelected regulators or politicians, both seeking power and hoping to gain at every issue by claiming they’re only interested in the earth, poor, frail, old, young-every subset of humanity as well as the exploitable flora and fauna infinitum, ad nauseam.
If only there was a scorecard of issues with consistent descriptions of : problem statements, quality of data, evidence, omissions, possibilities, probabilities, full transparency of analysis, assumptions, methods, costs, benefits, choices of action/no action/solutions and resulting personal/ public /national/ global priorities…all forced ranked by magnitudes and confidence in an accessible database.
You are on the right track. As hard as science is, selling it to the general public (and their political sycophants ) is even harder!

January 3, 2019 3:04 pm

These people would have called Einstein a “Gravity Denier” for bucking the scientific consensus.

January 3, 2019 3:22 pm

Okay, I just took serious note of the moderation request to focus on confidence levels, after I made my first comment supporting somebody else’s claim of “utter vapid stupidity”.

The fact is that the banner-child, confident claims of the report are based on false representations of extreme climate events. Actual data renders all that confidence meaningless. How does one support any amount of confidence using blatant falsehoods?

The fundamental basis for discussing those confidence levels seriously with any focus on technicality is missing.

The confidence levels themselves are falsehoods.

So, I’m back to “utter vapid stupidity”, except, this time, more widely applied.

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