Alarmist climate science and the principle of exclusion

AGW theorists are being misled by the principle of exclusion

Story submitted by Paul Macrae

In 1837, Charles Darwin presented a paper to the British Geological Society arguing that coral atolls were formed not on submerged volcanic craters, as argued by pioneering geologist Charles Lyell, but on the subsidence of mountain chains.

The problem, as Darwin saw it, was that corals can not live more than about 30 feet below the surface and therefore they could not have formed of themselves from the ocean floor. They needed a raised platform to build upon.

However, the volcanic crater hypothesis didn’t satisfy Darwin; he thought the atoll shape was too regular to have been the craters of old volcanos. There were no atoll formations on land, Darwin reasoned; why would there be such in the ocean? Therefore, Darwin proposed that corals were building upon eroded mountains, an hypothesis that, he wrote happily, “solves every difficulty.”

Darwin also argued, in 1839, that curious geological formations—what appeared to be parallel tracks—in the Glen Roy valley of Scotland were the result of an uplifted sea bed.

Darwin didn’t have any actual physical evidence to support these two hypotheses: he arrived at them deductively, through the principle of exclusion. A deductive conclusion is reached through theory—if X, then logically Y must be so—as opposed to induction, which builds a theory out of empirical data. The principle of exclusion works from the premise that “there is no other way of accounting for the phenomenon.”[1]

As it turned out, Darwin was wrong on both hypotheses. Later physical evidence showed that Lyell’s volcano theory was closer to the mark, and the Glen Roy tracks were caused by glaciers, which were still a mystery in Darwin’s time.

Darwin later wrote of his Glen Roy hypothesis: “Because no other explanation was possible under our then state of knowledge, I argued in favour of sea-action; and my error has been a good lesson to me never to trust in science to the principle of exclusion.”[2]

While Darwin rejected the principle of exclusion, at least as a primary scientific tool, alarmist climate science has not. Instead, the principle of exclusion is one of the most-cited arguments to support the anthropogenic global warming (AGW) hypothesis.

For example, in a 2010 interview with the BBC on the Climategate scandal, Climate Research Unit (CRU) head Phil Jones was asked: “What factors convince you that recent warming has been largely man-made?” Jones’s reply: “The fact that we can’t explain the warming from the 1950s by solar and volcanic forcing.” In other words, Jones is using the principle of exclusion: while he and his colleagues can’t prove that human activities are causing warming, they can’t find any other explanation.

Canada’s Andrew Weaver also relies on the principle of exclusion when he writes, in his 2008 book Keeping Our Cool: “There is no known natural climate mechanism to explain the warming over the 20th century. And that is one of the many pieces suggesting that a substantial portion of the warming of the 20th century is associated with greenhouse gases.”[3]

Similarly, the IPCC’s 2007 report notes: “Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.” The IPCC has no empirical proof that human carbon emissions are the main cause of planetary warming; the “proof” is that the scientists can’t find another explanation, i.e., the principle of exclusion.

It’s not unreasonable to claim that human activities are the main cause of global warming. If carbon emissions and temperatures increase at the same time, it’s possible they are connected although, of course, correlation does not equal causation. And many scientific theories are based on the principle of exclusion, including much of Darwin’s theory of evolution itself.

Where alarmists like Jones, Weaver and the IPCC betray the accepted principles of science is in claiming that a possible causal connection between human carbon emissions and temperatures is settled, certain, and, as Weaver puts it in his book, beyond debate (he writes: “there is no such debate [about the certainty of the AGW hypothesis] in the atmospheric or climate scientific community” (p. 22)).

Even worse, these scientists call anyone who dares to challenge their hypothesis a “denier,” deluded, a fraud, bought-off by the oil industry, or worse. One cannot imagine Darwin, a modest scientist, making similar claims of certainty for his two hypotheses, or throwing slurs at anyone who didn’t accept them.

Yet there may well be other explanations for a warming earth that we still don’t know about or enough about—the cosmic ray theory seems like a good contender, as do fluctuations in solar intensity and cyclical ocean temperatures: given the complexity of climate, there are many possible causes for a temperature rise (or fall).

But, then, the deductive rather than empirical (inductive) nature of alarmist climate science was stated clearly by climatologist Chris Folland two decades ago: “The data don’t matter… We’re not basing our recommendations on the data. We’re basing them on the climate models.”[4]

And so, alarmist climate scientists find themselves under siege by skeptics and increasingly distrusted by the public because they blindly accept the principle of exclusion, in the face of considerable empirical facts that don’t fit the AGW hypothesis. For example, for more than a decade, the earth has not warmed as the AGW hypothesis predicts. Nor are the oceans warming as the hypothesis predicts. Yet, when skeptics point out the problems, alarmists cannot admit they have made a mistake because then the whole alarmist edifice (and the juicy research grants that go with it) would collapse.

Darwin himself battled the principle of exclusion in proposing the theory of natural selection. Up to Darwin’s time, no one could think of any other way to explain the creation of species than by an all-powerful god. This led scientists and clerics into all sorts of logical absurdities, such as claims that the earth was mere thousands of years old or that God had put fossils into the earth to test scientists’ faith. However, in the mid-1800s, there was no better explanation to hand.

Darwin (and Alfred Russell Wallace) supplied a better, more scientific explanation: nature itself, acting over eons of time, was the creator of species, an hypothesis so simple and so logical that Thomas Huxley, Darwin’s main promoter, declared: “How extremely stupid not to have thought of that.”

The AGW hypothesis may well prove to be correct. However, the simplest and most logical explanation for climate change, in the past, now, and in the future, is natural variation. If so, then the AGW hypothesis, based on the treacherous principle of exclusion, will go the way of Darwin’s two hypotheses on the Glen Roy tracks and the creation of coral atolls.

And so, while alarmist climate scientists are quite within their rights to propose the AGW hypothesis, they should also be cautious: AGW is an hypothesis. It has not reached the status of a scientific theory (it has not passed enough scientific tests for that), nor is it a scientific fact, as the public is told. Instead, alarmist climate scientists have thrown the proper scientific caution to the winds to make claims that aren’t supported by the evidence, and to smear those who point out the possible errors in their hypothesis.

To repeat Darwin’s words: “My error has been a good lesson to me never to trust in science to the principle of exclusion.” This caution is especially true when climate-science errors could lead to anti-carbon policies that will cost billions of dollars and destroy millions of livelihoods, while having no effect upon the climate because humans are only a small part of a much larger picture.

Darwin gave good advice: beware the principle of exclusion. It’s a pity that today’s alarmist climate scientists are unwilling to heed that advice.

[1] Darwin’s thought process is described in Gertrude Himmelfarb, Darwin and the Darwinian Revolution. New York: W.W. Norton, 1962 (1959), pp. 99-106.

[2] Charles Darwin, Life and Letters, I, London, 1887, p. 69. Quoted in Himmelfarb, p. 106.

[3] Andrew Weaver, Keeping Our Cool: Canada in a Warming World. Toronto: Viking, 2008, p. 59.

[4] Quoted in Patrick J. Michaels, Sound and Fury: The Science and Politics of Global Warming. Washington: Cato Institute, 1992, p. 83.

Paul MacRae is the author of False Alarm: Global Warming—Facts Versus Fears, and publishes the blog False Alarm at


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Phillip Bratby

Bob Watson, serial bureaucrat, ex-IPCC chair and long time chief scientific adviser to Defra in the UK has on numerous occasions publicly stated “There is no known natural mechanism to explain the recent warming” and “the overwhelming majority of scientific experts believe that human-induced climate change is inevitable”. He is a believer in the principle of exclusion, appeal to authority and belief over evidence.
He is typical of the problem we face in the UK in trying to get a return to scientific integity and sanity.
We need to repeal the Climate Change Act and get a sensible energy policy.

jim hogg

Nicely argued and written. A tough point for the AGW “the science is settled” brigade to answer.
PS The Scot, Patrick Matthews, trumped Darwin by about 24 years on natural selection, in a note to a text on arboriculture for boatbuilding timber, of all things, if my memory serves me correctly. He thought it was so obvious that it was hardly worth mentioning!

John Shade

What a fine essay! The sorry intellectual state of CO2 alarmism, and of various scientific establishments which have chosen to defend or even promote it, would be no more than a source of wry amusement in academia were it not for the widespread acceptance of this alarmism by policymakers and others in positions of power or influence.

Couple the principle of exclusion with the precautionary principle and there are real troubles in the offing.

In itself the precautionary principle sounds harmless enough. We all have the right to be protected against unscrupulous applications of late twentieth century scientific advances – especially those which threaten our environment and our lives. But the principle goes much further than seeking to protect us from known or suspected risks. It argues that we should also refrain from developments which have no demonstrable risks, or which have risks that are so small that they are outweighed, empirically, by the potential benefits that would result. In the most recent application of the doctrine it is proposed that innovation should be prevented even when there is just a perception of a risk among some unspecified people.


Diagnosis by exclusion is based on the assumption that ALL the possible causes are known. In medicine this comprises a ‘differential diagnosis’ a working list of possible causes from which clinical tests can be performed to exclude/confirm candidate causes. In the case of climate science the assumption becomes ‘ALL the possible causes AND their feedbacks (positive/negative) are known and have been quantified’.
Given the complexity of the climate system and its non-linear, chaotic behaviour the assumption does not seem to be justified.
PS In medicine it is not uncommon to adopt a ‘working diagnosis’ (based on known circumstances, prevalence, etc.) for purposes of management while working towards confirmation/exclusion. Positive diagnosis is usually required. However, problems arise when a new disease appears (e.g. the early experiences with HIV/AIDS, toxic shock syndrome etc.) when intensive investigation and open-minded involvement of a multi-disciplinary team may be needed to understand and manage the condition.


Excellent article. Thanks

I think this is a good point. However, when I tell people that tornados and floods are no more proof of Climate Change than they are of Leprechauns they tend to think I’m just nuts. What else could explain believing in such unlikely things?


Fantastic article. Should be sent to every climate scientists and politician involved in the AGW scam.

Thanks; simple, clear, straightforward and balanced.

Stephen Skinner

“But, then, the deductive rather than empirical (inductive) nature of alarmist climate science was stated clearly by climatologist Chris Folland two decades ago: “The data don’t matter… We’re not basing our recommendations on the data. We’re basing them on the climate models.”
Models are used effectively by modern manufacturers to aid in the design of complex design and materials. However, as most here will understand, Boeing had to rethink it’s design model for the wings of the 787 when they failed in testing. Can anyone imagine Boeing stating after the wings had failed “The data don’t matter… We’re not basing our design on the data. We’re basing them on the design models.”


To be blunt; Alot more of us that know a little about this topic but not enough to evaluate high level discussion independently would be more understanding of the skeptical side if obvious charlatans, some of which that have multiple appearances on this very site, didn’t get such uncritical applause from what seems to be a plurality of skeptics. There is no excuse for holding people such as Christopher Monckton in high esteem.


There clearly hasn’t been any warming, so I’m not sure what Mr MacRae is writing about here.
We shouldn’t exclude the possibility that measurements that have suggested warming might be happening may simply be wrong.

Ed Zuiderwijk

And a “science” based exclusively on the principle of “exclusion”, and does not let any real data stand in the way of its “theories”, is called: a pseudo-science.


Thanks Paul, a useful point to make in arguements with AGWers.

C Porter

An excellent post and my thoughts exactly, but put much more succintly.
I pull what is left of my hair out everytime I hear our Chief Scientist Beddington and his predecessor King say “Well we can’t think what else it can be, so it must be due to CO2.” These cannot be real scientists with such flawed logic, and are never called to account for their ridiculous statements by the political media.

John Marshall

Good Post.
Alarmists continue to claim that temperature rise is caused by CO2. High resolution data from both ice caps, Greenland and Antarctica, show that the opposite happens, temperature rise causes a parallel rise of atmospheric CO2. ie. their cause is driven by the event which makes a mockery of the data, and themselves.


It is worse than that. As you say the principle of exclusion operates when there is NO other explanation from reason or deduction. Here we have exclusion operating when there is indeed by deduction an alternative explanation available that is at least equally viable – natural variation. And so our current position is in fact the result of a deliberate choice made between two possible explanations, both of which it seems to me are equally viable from reason alone (and if one acepts that climate has changed in millenia gone by one might say that the proper application of reason to the issue would result in a preference for the idea of natural variation). In my view we do not have the exclusion principle operating here in a “pure” sense, but a deliberate “exclusion” of at least one other explanation that is equally viable from reason alone in favour of the AGW hypothesis. What I am saying is that if one aplies reason and deduction alone one is more likely to arrive at the conclusion that natural variation is the correct explanation.
But deduction is not the only method of considering natural variation to be a possible explanation – there is now growing empirical evidence of this natural variation which is beginning to overrun the chosen AGW conclusion based on modelling and deductions therefrom, (and even from what empirical evidence is also now deployed in support of it). So here exclusion is applied resulting in pushing the AGW hypothesis in the face of reason AND empirical observations which point to the contrary or at least to a very minor overall impact of the AGW hypothesis, if true.
Then, on top of this “selective” exclusion is applied the “precautionary principle” which removes the debate even further from the first principle of explaining the various possibilities and into other considerations which are deemed urgent – by doing this those who chose AGW have moved the game beyond the academic search for an explanation of climate change so that anyone talking about these first principles is described as “behind the game” or, as we see so often, challenging that which is “settled”.
Darwin had the good sense and grace to recognise when his “best guess” unravelled. He was a true scientist.
Chris Folland’s remarks are the only explanation for how this state of affairs exists.

J. Simpson

“Jones’s reply: “The fact that we can’t explain the warming from the 1950s by solar and volcanic forcing.” In other words, Jones is using the principle of exclusion: while he and his colleagues can’t prove that human activities are causing warming, they can’t find any other explanation.”
This is also the main argument offered to the lay public by the UK Met Office in thier “climate guide”.


Tucci78 – we were thinking the same thing at the same time, it seems 🙂


The power of science as an investigatory/explanatory mechanism derives entirely from adamant unwillingness by scientists to make claims in the absence of empirical evidence. The difference between science and religion boils down to comfort with ambiguity. The theologian attributes all otherwise unexplainable phenomenon to non-falsifiable mechanisms, whereas the scientist is – MUST – be comfortable saying “I don’t know.” Hypothesization is fine (indeed, mandatory), but it is also mandatory for scientists, if they are to merit the title, to adapt hypotheses in the face of contradictory observed data, and to jettison hypotheses that cannot be adapted to explain observed data.
For a scientist to say, “Even though we have no empirical evidence and haven’t been able to demonstrate a causal mechanism for global warming/climate change/climate disruption, it MUST be carbon dioxide – and human-produced carbon dioxide, at that – because there isn’t anything else” is a betrayal of science because it implies perfect knowledge, which is a theologian’s argument. It implies that all other possibilities have been eliminated, which ignores two other logical possibilities: it’s something we’ve thought of and is logically plausible, but haven’t been able to find data to support; and it’s something we haven’t even thought of. Real scientists have to be willing to say things like “This hypothesis has not been validated by observed data”, “This hypothesis has been falsified by observed data”, and most important of all, “I don’t know.” Real scientists don’t nail their colours to the mast of any one theory until it has accumulated an overwhelming mass of validating empirical data, without a SINGLE instance of falsifying data. Einstein put this principle best when he said, “A single experiment can prove me wrong.”
The Svensmark case is a textbook example of this. On one side of the ledger we have the anthropogenic CO2 forcing hypothesis, for which no causal mechanism (nor even a correlation!) has been observed and for which there is no validating evidence – and, in fact, a large and ever-increasing body of contradictory empirical evidence. On the other side, we have the low cloud nucleation by GCR hypothesis, for which both a correlation and a causal mechanism have been empirically demonstrated, and for which there is a significant and growing body of observed evidence validating the argument. Yet climate “scientists” continue their attempts to shore up the former and decry the latter.
There are plenty of words that may be used to describe someone who continues to support a demonstrably falsified hypothesis while ignoring an increasingly validated one, but “scientist” isn’t one of them.


Excellent article, Paul. Thank you.
Re Glen Roy and its ‘parallel roads’. I had understood that they are now interpreted as beaches of a former glacial lake. There are currently no glaciers in Scotland (although they’ll doubtless be back some day as the Milankovich cycles turn), but there were formerly glaciers flowing off the Ben Nevis range which are thought to have blocked the outlets of several valleys including Glens Roy, Gloy and Spean, in each of which the ‘fossil beaches’ are preserved.

What are you, Mr. Projection? Have you never seen the fawning acceptance of the most ridiculous, wild-eyed statements on climate progress, RC, etc? Further, those blogs heavily censor comments such as yours. You can give such opinions here because WUWT allows and promotes all views. Readers can then make up their own minds instead of being spoon fed one-sided alarmist propaganda.
Finally, Lord Monckton is willing to go toe-to-toe and debate any of the alarmist crowd at any time. He has spanked them good and hard, so now they’re reduced to taking pot shots from the safety of their ivory towers. They will no longer debate him because he is knowledgeable and competent, and he publicly puts them to shame. I am proud to have someone on the skeptics’ side who is never afraid to debate. The alarmist crowd certainly fears Monckton. That explains their impotent name-calling.

Alex Buddery

Modern scientific method is founded on deductive logic not inductive logic. You misrepresent deductive logic in that you say it is not based on empirical evidence but it is. In inductive logic you look at the empirical evidence that you have and then decide how the world works from this. In deductive logic you look at the empirical evidence and form a hypothesis from which you deduce what would happen in an untested situation which is likely to prove your hypothesis wrong. You then execute the untested situation and see if you correctly deduced the outcome. This is how the modern scientific process works.
As Karl Popper describes, inductive logic is fundamentally flawed because it creates universal statements from singular ones. As more singular statements are added it is possible to simply induce different universal statements to explain them. This is also flawed in that you cannot assign probability to universal statements and thus you have no indication of how reliable your universal statements are. To quote Popper ‘my own view is that the various difficulties of inductive logic here sketched are insurmountable’. With deductive logic you derive singular statements from universal ones and in this way are able to test your singular statements empirically to support your universal statement. As probability can be assigned to singular statements you can also have a reasonable idea of the chances of disproving your universal hypothesis with your experiment. To quote Popper again ‘the method of critically testing theories, and selecting them according to the results of tests, always proceeds on the following lines. From a new idea, put up tentatively, and not yet justified in any way-an anticipation, a hypothesis, a theoretical system, or what you will-conclusions are drawn by means of logical deduction’


Monckton is on the level of Al Gore. I do not have a high opinion of climate progress. Rebuttals on articles here are often laid out in a easily understood and highly descriptive manner (Pat Franks last one here is last example). I’ve seen the same quality level directed at something from Real Climate….only once. Not to mention their index is one of the best repositories of information on this out there.

The principle of exclusion fails as it presumes we know all the possibles, and we don’t…

Starwatcher says:
“Monckton is on the level of Al Gore.”
If you believe that then we are too far apart on the issue to have a meaningful conversation.
A debate between Gore and Monckton would be the equivalent of Bambi vs Godzilla.


Very good post.
The self named climate scientists also have used the exclusion principle, to well, exclude the publication of papers
which they disagree with.
Certainty is madness?

Andy G55

As I see it, the most likely place to find the principle of expulsion used as the basis, is in a religion.

Chris Wright

An excellent article. I had long been familiar with that particular argument, but it’s nice to have a convenient label: the exclusion principle. To have Darwin himself speaking against it is a nice piece of ammunition!
Of course, the exclusion principle as practised by climate scientists is complete nonsense. The very obvious problem is this: the very people who apparently can’t find other explanations are the very same people who don’t *want* to find other explanations. If they could find an alternative that completely explained the 20th century temperature rise, then there would be no place left for carbon dioxide – and that wouldn’t do, would it?
Another point. Are they able to explain the MWP and the earlier warmings? If not, then their ‘proof’ falls down completely – because CO2 levels were completely natural, as SUV’s and international air travel hadn’t really caught on in the Medieval and Roman periods. Oh, hang on – they solved that small problemette by ‘getting rid’ of the MWP.
In my opinion, having to invoke the exclusion principle is a pretty good indication that their theory is wrong. Real theories, Relativity being a perfect example, can only be proven by data and experiments that confirm predictions made by the theory. There doesn’t appear to be any genuine, empirical proof of AGW at all. And yet the world is poised to bet countless trillions of dollars on this unrproven theory – a theory that is almost certainly wrong.

At 1:26 AM on 8 June, gyptis444 writes:

Diagnosis by exclusion is based on the assumption that ALL the possible causes are known. In medicine this comprises a ‘differential diagnosis’ a working list of possible causes from which clinical tests can be performed to exclude/confirm candidate causes. In the case of climate science the assumption becomes ‘ALL the possible causes AND their feedbacks (positive/negative) are known and have been quantified’.
Given the complexity of the climate system and its non-linear, chaotic behaviour the assumption does not seem to be justified.

Not only that, but there’s the even more egregiously unjustified assumption that the evidence being used to advance the AGW contention hasn’t been so thoroughly “cooked” that the promulgation of this fraud needs to be moved from the Weather Channel to the Food Network.
Though I really don’t think that even Alton Brown could come up with something to sell this preposterous bogosity.

PS In medicine it is not uncommon to adopt a ‘working diagnosis’ (based on known circumstances, prevalence, etc.) for purposes of management while working towards confirmation/exclusion. Positive diagnosis is usually required. However, problems arise when a new disease appears (e.g. the early experiences with HIV/AIDS, toxic shock syndrome etc.) when intensive investigation and open-minded involvement of a multi-disciplinary team may be needed to understand and manage the condition.

Well, I remember when we were calling it GRID (gay-related immune deficiency) and there was serious consideration that it was being caused by amyl nitrate “poppers” then being used by sexually promiscuous males indulging in “fisting.” Before we had an identified retrovirus (HIV-1) and reliable serological testing to provide evidence of infection with the pathogen, we had begun to get a handle on the prevalence of the epidemic by using reliable serological markers for Hepatitis B, which is a virus also quite commonly transmitted by way of the same kinds of sexual contact and parenteral (IV) drug use through which HIV-1 has proven to be acquired.
Most people don’t realize that the constellation of opportunistic infections first noticed in AIDS cases (one of the annual multidisciplinary international meetings of greatest value in the cutting-edge research on HIV infection is still the CROI – the Conference on Retroviruses and Opportunistic Infections) were not unfamiliar to doctors in the developed or developing world. Congenital, malignant, and iatrogenic immune deficiency syndromes – the last category most commonly seen in patients on cytotoxic chemotherapy regimes for the management of malignant diseases – had been identified and were being addressed long before AIDS came out of Africa to start killing people all over the world.
A lot of the time you have to initiate treatment on the basis of disconcertingly tenuous “horseback” diagnoses because if you wait for the empirical evidence to come in, the potential for morbidity – and mortality – as well as economic treatment and recovery costs become damned adverse. You just gotta keep that “non nocere” bit in mind.
Is it any wonder that Arthur Conan Doyle – an ophthalmologist – modeled his Sherlock Holmes character on a demon diagnostician who’d been one of the author’s instructors in medical school?

Andy Mayhew

Coldish is correct re the Parallel Roads – they are now believed to be the shorelines of a glacial lake. So Darwin wasn’t too far off the mark.
btw if the warmists were predicting warming for the past 10 years and (some) sceptics predicting cooling over the same time period and we end up with a fairly static temp trend, what does it tell us? Maybe they were both right?


Debates are poor mediums for discussing anything that is empirically based. The reason I conflated them both, is because they both look good until you fact check.

Hector Pascal

A slight clarification here. The “parallel tracks” used to be marked on the old OS 1 inch to 1 mile maps as parallel roads. When I were a nipper in the scouts, their origin was explained as them being beaches formed at the margins of (temporary) glacially dammed lakes.

You want to discuss empirical facts? Then answer me this. The central claim of the alarmist contingent is that CO2 is harmful. Let’s ‘fact check’ that assertion: provide empirical evidence showing global harm from CO2. Such evidence must be testable and falsifiable, per the scientific method.
The fact that there is no such evidence does not eliminate CO2 as the cause of global warming. It does point out that there is no evidence that CO2 causes global warming. None. That makes for an incredibly weak argument, based on faith rather than data.


I’ve talked about this many times. It’s not that they know humans caused it. It’s that they’re ignorant of the cause and their lack of imagination is their proof.

The problem isn’t really the exclusion principle, it’s a religious mindset. Before the Mead/Schneider gang took over climate science, everyone who analyzed climate scientifically understood the influence of sunspots, and took sunspots into account. When the Carbon Cultists monopolized the discipline, they automatically turned every explanation other than CO2 into Unfacts. Sunspots can’t be the explanation because sunspots can’t be the explanation. Why? Because we know. It’s an axiom, not a fact.


The IPCC took over a thousand pages to make their case, and you want me to provide that chain of logic in an internet post? Sorry, but the world isn’t always so simple where big sweeping questions like that can be answered in brevity. Besides, I’m more of a consensus guy. Way I look at it is Atmospheric Physics is hard! I banged my head against it for a while and still don’t get alot of it. But what the hell, I do know a little. If you can pick a topic a little more precise then is CO2 bad I’m game

Roger Knights

@ Starwatcher:
Monckton is not blameless. Many of us here recognize that. I’ve said so here several times. But he stacks up very well against his critic Abraham. Here’s the first video in a series of videos titled “Monckton Refutes Abraham”:

Alexander K

An excellent, clearly-written post.
I shall be using ‘The Exclusion Principle’ in future discussions with Warmist acquaintances.

How is the “Principle of Exclusion” any different from the fallacious “Arguement from Ignorance?”

Alexander K

Anthony, what happened to the clear, easy-to-read script that was a feature of ‘Leave a Reply’?
The new model is damnably hard on elderly eyesight!
[Reply: This comment should be posted in Tips & Notes, which Anthony always reads. Any other comments regarding the small font should be posted there as well. ~dbs, mod.]

richard verney

The reliance upon ‘there being no other known explanation’ for what is being observed is not proof of anything other than the fact that we do not have sufficient knowledge about and understanding of the system being observed. It is simply an admission of ignorance, since if we had sufficient knowledge and understanding of the system in question we would be able to positively explain and prove empirically the cause behind the observations in question.
The precautionary principle is fundamentally misconceived since its limits are constrained by no more than one’s imagination and is therefore always as long as a piece of string. The precautionary principle always begs the next question, what if the percieved threat is not curtailed by the action thought to be necessary and desirable? What happens then?
For example say that we spend spend trillions of dollars in decarbonising the world and say that this does not have any noticeably effect on temperatures which continue to rise at an accelerated rate (say because what is driving upward temperatures is not CO2 but something different) and say that these rising temperatures bring about the disasterous consequences that the CAGW crowd claim that will occur (eg., drastic sea level rise, crop failures, droughts, prolonged excessive heat waves, melting of ice caps and glaciers etc). What happens then if we have effectively bankrupted the developed economies? The developed world will not have the financial wherewithall to spend yet further trillions on required adaption. Indeed, it will not be able to muster the industrial might to conduct the constructural challenges that adaption would require since it has killed off its industry (possibly forcing these overseas etc). The developing nations will not have the industry, skill set, expertise nor infrastructure to carry out the required construction and indeed, these countries may well (in this scenario) be on their knees through drought and famine etc so that they could not conduct the required and necessary adaption. Thus the precautionary principle demonstrates that mitigation is not the answer because one always has to ask what if that course of action goes wrong and does not solve the problem or perhaps even what if it makes the situation worse (there is always a chance that with a system not well understood, reducing CO2 ,may make matters worse eg., by stunting forest, plant and crop growth).
What we shoulkd be doing is not focusing to the exclusion of all other causes on just one ‘culprit’ and we should be looking for a proper and full understanding of the system so that we can positively explain what is going on rather than saying we can think of no other explanation. If mankind had simply been prepared to accept that we can think of no other explanation, we would be stuck in the dark ages with hundreds of gods explaining events surrounding us. Fortunately, there are some who are not so blinkered or complacent and will strive to know and understand the world around them.


Is it any wonder that Arthur Conan Doyle – an ophthalmologist – modeled his Sherlock Holmes character on a demon diagnostician who’d been one of the author’s instructors in medical school?
Sherlock Holmes works simply because ACD can posit that SH has perfect knowlege of any pertainant fact. It’s fiction. 🙂 Imagine how SH, with his old knowlege, would have trouble deducing modern crimes comitted using cell phones, infrared scanners, etc, etc.
“The only reasonable explaination is that the gunman made a deal with the Devil to observe the movements of the occupants of the house from 400 yards away through solid brick. All other reasonable explainations have been exhausted, so whatever remains, however outlandish, must be true.”

Mark in Oz

“Besides, I’m more of a consensus guy.”
You just blew your credibility out of the water with that lame admission.

Larry Fields

Good job, Paul. Philosopher Larry’s stoopid question of the day: Isn’t the Principle of Exclusion a glorified version the classical logical fallacy: Argument from Ignorance?


Yes the medical analogy is a good one as medicine is dealing with an extremely complex system just like the global climate. That’s where I find the term ‘Climatologist’ and the consequent pseudo-science of ‘Climatology’ so pathologically presumptuous. It’s like me and a few jumped up mates getting together and calling ourselves peer reviewed Humanologists and the doyens of the settled science of Humanology(what you haven’t heard of us?) and all bow to our new edicts and prescriptions henceforth. How often have you heard some scientist commenting upon climate research pooh poohed for not being a ‘Climate Scientist’ or ‘Climatologist.’ You can instantly see how the current ignorati and deniers in medicine, psychology, biology, sociology, economics,etc can all be subsumed by we superior Humanologists in the know about all such things. Welcome to the very essence of the exclusivity of climatology today.

richard telford

Still waiting for the deus ex machina?


This is such a delightfully moderate piece, it would be interesting to see it in print in the MSM together with an invitation to major protagonists to offer their personal responses.
For example, in the UK it should be an irresistible challenge to people like Beddington, Paul Nurse, etc. on the one hand, and Monckton, Lawson, etc. on the other – for the enlightenment of the general public, not just those of us who already hold a view.
I deliberately omit mention of those actively involved in ‘climate science’ itself, on the grounds that anything useful they might say on the matter would be hopelessly compromised by legal advice.


Can anyone explain to me why soot (black carbon), can’t be one of the biggest contributors to our recent wave of warming? We have been steadily pumping it out since the industrial revolution began, besides being a GHG that warms the atmosphere it also accelerates the melting of ice when it lands on it and introduces more water into our hydrosphere. Water vapor, being the greatest GHG of them all, warms the earth and causes the soil to respire Co2 more and a downward spiral begins.
That story of the man towing iceburgs seemed to me a apt metaphor. It’s not the Co2, it’s man’s effect on the hydrosphere that should be focused on.

Tom in Florida

Since all religions are based on the principle of exclusion, AGW clearly meets the criteria for a religion.