Occam's Razor and Climate Change

Trenberth demanding that the null-hypothesis be reversed in the case of the unproven radiative global warming hypothesis was one of those “how low can they go?” moments in climate “science”. But there have been so, so many…A veritable litany of shame.

And yet since 1998, even with the increase of CO2 continuing, there has been no significant increase in warming. Just because someone wrote that warming from 1975-1998 was clearly caused by Anthropogenic CO2 does not make it so. Give it another 10 winters like the most recent, the citizens USA & Canada may have voted with their feet.

Martin at 12.28 am
– I am so relieved to learn that there are only two natural influences that could possibly affect global temperature. That makes everything so much simpler!
Great post Eric Worral – thank you

Presentations against the “null hypothesis” tend to, in subtle implicit steps:
Step 1) focus on a stated fingerprint of human influence
Step 2) then spin around to act like it was responsible for all of around 0.6 degrees Celsius net warming over the past century compared to a cold part (the early 20th century), rather than how even total average temperature rise (let alone that from human influence alone) was far less, if any, compared to the late 1930s in non-rewritten data
Step 3) then spin around to pretend it will cause an order of magnitude more (several degrees) this century
But, while misrepresenting the history of natural forcings versus temperature is possible in text and in “adjusted”-data plots, otherwise a dominant influence of natural albedo change is blatant and fits history: from the MWP & LIA, to the warmth in the mid 20th century, to the 1960s-1970s global cooling scare, to the later global warming scare, and the subsequent “pause.” That can be seen in my usual http://tinyurl.com/nbnh7hq illustration.

Ben D
If you were a climate “scientist” you would know that you have good CO2 and you have evil (fossil fuel produced) CO2. The evil CO2 leads to thermageddon, simples!
So cooling and warming are not inconsistent with AGW!

Steve
That pattern is PDO index. Roughly 30-year cycle matching the above warming and cooling periods. Roy Spencer studied this correlation and said 75% of 20th century temperature trend can be explained by PDO.

Have supporters of the consensus ever claimed that natural variation is properly understood? If not their claim that the science is settled was clearly bogus from the start – and they knew it.
On the other hand, if they really do think that natural variation is understood have they published an explanation of it anywhere on the web that could be understood by a lay person?

Great (and more importantly, clear) post.
FD

Martin says:
March 22, 2014 at 12:28 am
From the article that Eric Worrall linked to:
D – Do you agree that natural influences could have contributed significantly to the global warming observed from 1975-1998, and, if so, please could you specify each natural influence and express its radiative forcing over the period in Watts per square metre.
“When considering changes over this period we need to consider all possible factors (so human and natural influences as well as natural internal variability of the climate system). Natural influences (from volcanoes and the Sun) over this period could have contributed to the change over this period. Volcanic influences from the two large eruptions (El Chichon in 1982 and Pinatubo in 1991) would exert a negative influence. Solar influence was about flat over this period. Combining only these two natural influences, therefore, we might have expected some cooling over this period.”
And instead of cooling from 1975-1998 we saw warming, which was clearly caused by Anthropogenic CO2 seeing that natural influences during that period had a cooling effect!
Yeah, the old logical fallacy that supposes that in order for a heat source to cause a body to warm, said heat source must be continually increased. And yet even a child knows that if a pot is simmering away on a low flame, and then the flame is turned up in a single step, the pot will gain heat over some period of time afterwards, as it seeks equilibrium. The flame is “about flat over this period” and yet the pot continues to warm. Get it? If you do then you understand more than most climate scientists.

lgl says:
March 22, 2014 at 2:39 am
“Fine, but what is the ‘simplest explanation’ for the 1880-1998 rise?”
—————————————–
Solar activity.
Climastrologists claim that because TSI varies so little between solar cycles it can not possibly be the cause.
But climastrologist do not understand how the sun heats the oceans. Due to the mis-application of blackbody calculations to transparent materials they claim a temperature for the oceans of -18C in the absence of DWLWIR. This figure is provably incorrect. The number they were looking for is +80C in the absence of atmospheric cooling. The reason is that solar SW and UV penetrates to depth in transparent water and heating is cumulative due the the slow speed of non-radiative energy return to the surface.
While TSI only varies ~0.1% (after the solar record has been thoroughly stamped flat), it is the higher frequencies that vary most. Great variation is evident in solar UV. Some claims indicate an increase of 6% or greater since the little ice age.
And the strength of solar UV-A at 50m depth is still in the order of 10 w/m2. 50m is below the thermocline where energy can more easily accumulate over time.

Don’t look now but with the new February data NCDC says 2014 is not even on pace to be a “top 10” year. With every month that goes by the alarmist’s call to The Pause (TM) gets more complex, and Occam’s call gets louder…

@ lgl
You’ve got it in a nutshell. What we are best at here in the Village is sniping at climate scientists and their explanations – not necessary to explain anything ourselves

Konrad says, March 22, 2014 at 3:13 am:
“lgl says:
March 22, 2014 at 2:39 am
“Fine, but what is the ‘simplest explanation’ for the 1880-1998 rise?”
—————————————–
Solar activity.”
Konrad,
lgl has been presented with this answer a multitude of times. He still ignores it. You can see it in the way he chooses to give his reply to RichardLH only, not to you. Deep down inside he knows your answer is the correct one. That’s why he systematically avoids addressing it. “No! It’s the CO2 what done it! It has to be!”
On a slightly different note, the ‘solar pond’ shows us pretty well how quickly and efficiently solar heat stores up in water that is not allowed to convectively/conductively cool. In reality the cooling of course happens at the surface and primarily through evaporation, but the principle stands. Thermal radiation alone could not adequately cool the oceans being heated by the sun. Not until they got really hot, close to boiling.
http://en.wikipedia.org/wiki/Solar_pond

Occam’s Razor does NOT say “The simplest explanation is usually the correct explanation”.
The principle states that “Entities should not be multiplied unnecessarily.”
Two different concepts.
The most useful statement of the principle for scientists is:
“when you have two competing theories that make exactly the same predictions, the simpler one is the better.”
Simple example:
1 + 1 = 2, there is no need to say (5-4) + (6-5) = 2
Both are correct but the first is the simpler one and better to use.
Occam’s Razor is often used incorrectly by those who do not understand it or by those who know better and are trying to justify something that isn’t true. Incorrect usage of the principle immediately sets off my sceptic alarm.

Temperatures in February 1878 were exactly the same as February 2014.

The Warmists/Alarmists have made Occam’s Razor into Gillette’s Razor with 5 blades and flex head. It’ll do anything you want…… ;^D

Reblogged this on Sierra Foothill Commentary and commented:
The problem is that our political leaders in Sacramento do not believe in Occam’s Razor, only in the myth of anthropogenic warming.

Occam was a 14th c Christian scientist, an era populated by geniuses who built modern math and sciences, yet we are told this was a ‘dark age’, even though we still use ‘laws’ developed during this time [see impetus, average velocity, gravity etc]. I would say that today is the ‘dark age’ when something as insidious, stupid and non-scientific as globlaoneywarming is ‘consensus’. Reminds me of abiogenesis, a ‘law’ which was ‘consensus’ for 2100 years and still believed in by evolutionists…..whoops.

RichardLH says:
March 22, 2014 at 6:58 am
re: Tom in Florida says:
March 22, 2014 at 6:24 am
“Occam’s Razor is often used incorrectly by those who do not understand it or by those who know better and are trying to justify something that isn’t true. Incorrect usage of the principle immediately sets off my sceptic alarm.”
So there is acknowledged natural variability in 2, 3, 5, 12 and ~60 year ‘cycles’ but the greater than 75 years rise is definitely down to CO2?
What would you conclude is the Occam’s Razor statement for that?
========================================================================
I wasn’t making a comment on the article but rather a general comment about the incorrect use of Occam’s Razor, to wit: “The simplest explanation is usually the correct explanation” at the start of the article. Just one of my many pet peeves.

The null hypothesis is that anthropogenic C02, comprising an negligible .0017% of the atmosphere, has a negligible effect on the earth’s climate. Extraordinary claims require extraordinary evidence, especially when the proposed mitigation is de-industrialization (ever notice that progressives are anti-progress?) and a massive lowering of civilization’s standard of living. The claim that the flattening of global temperature for the past decade and a half is due to “natural variation” (as Trenberth remarked, a fancy term for “we don’t know”) is actually a counter-argument to the AWG hypothesis. A natural forcing strong enough to temporarily reduce the trend in place since at least the 1850s is also strong enough to explain the enhanced trend during the warming scare of 80’s and early 90’s. Science must refute this simple, natural explanation with proof of human attribution without relying on climate models which have proved themselves to be without predictive power.
lgl says:
March 22, 2014 at 2:39 am
“Fine, but what is the ‘simplest explanation’ for the 1880-1998 rise?”
Solar insolation and ocean dynamics. The ocean is a massive heat storage reservoir, an obvious fact that seems to have been lost on climatologists until recently recognized while floundering about in search of the “missing heat”. As such, the amount of energy contained in the ocean is sensitive not just to the TSI, but to asymmetry in the TSI. If more heat is added in the warming part of the cycle than is released in the cooling part, the next cycle starts from a higher baseline. Taking this integrative effect in to account and adding in the observed AMO/PDO variations accounts for 94% of the observational record. (see this plot and it’s derivation here.

Occam’s Razor isn’t an absolute rule of reason, because sometimes the actual explanation is, in fact, the more complex of two hypotheses. That is, nature itself is not obligated to be “simple”.
The correct (mathematical) way to approach this is from the point of view of Bayesian statistics. The advantage of a simple hypothesis is that it has fewer Bayesian priors. This means that it is (usually) more probable because the Bayesian priors occur in conjunction — if every assumption underlying a hypothesis comes with a probability of being wrong and only one assumption has to be wrong to make the hypothesis untrue, then fewer assumptions (all with an equal chance of being wrong) is better than more assumptions.
However, all assumptions do not have an equal chance of being wrong. A hypothesis that depended on, say, the correctness of Newton’s Law of gravitation for simple macroscopic objects in non-relativistic context and one other 50-50 assumption is not automatically less likely than a competing hypothesis that depends on only one 50-50 assumption, because the law of gravitation is probably correct out in the 0.9999….. range.
Bayesian scientific reasoning (as explained in Jaynes’ classic work Probability Theory, the Logic of Science) deals with Occam’s razor not in verbal terms involving leprechauns, but in terms of using incoming data to recompute the prior probabilities. Even if we truly believed strongly in gravity as a prior probability close to unity, evidence is capable of causing us to reduce that probability as experimental data inconsistent with the theory accumulates, and eventually falsify (in the sense of “make very very improbable”) not just the hypothesis in question, but its prior assumptions.
The classic example of this is you are given an electronic coin flip program that uses a perfect (by assumption) random number generator to produce random 0’s and 1’s with some unknown probability. You use that generator to drive a game, perform a computation, or just do some counting that requires 0’s and 1’s to occur randomly with equal probability. The game/counting is your hypothesis — “If the generator produces 0’s and 1’s with equal probability, then in the long run my counts will be distributed according to a binomial distribution with p = 0.5”. The assumption is clearly evident.
Bayesian reasoning gives you a way of starting with a prior assumption of probability of p = 0.5 and effectively weight it with the strength of your belief that it is true, and then gradually modify it as you generate a string of 0’s and 1’s in such a way that it converges on the frequentist definition of probability in the limit of infinite trials but differs in the beginning where one has a strong bias towards an unbiased coin flip, as it were. Maximum entropy rocks and posterior probability computation rocks as well.
A second objection to the assertion that no-CO_2 hypotheses are “simpler” than CO_2 hypotheses is that a data with a known, clearly evident degree of complexity has to be explained by a hypothesis at least sufficient of producing that degree of complexity. It obviously cannot be explained by a theory that cannot produce that degree of complexity, but there is nothing like a uniqueness theorem or minimum complexity theorem for general scientific hypotheses.
For example, if one’s data exhibit curvature, one cannot use a hypothesis that only produces a linear response to explain it. One has to have a theory at LEAST complex enough to produce/predict data with curvature, a quadratic theory or higher. But one cannot easily specify that a quadratic theory is better than an exponential theory in spite of the fact that quadratic specifies only three terms in a Taylor series where an exponential specifies an infinite number of terms. Lots of physical phenomena are exponential. Or sinusoidal, ditto. So Occam’s Razor cannot be naively applied.
In the particular case of climate science, nobody (sane) would claim that CO_2 concentration is likely to have zero effect on the climate, because a lot of physics with prior probability (determined by independent theory and experiment) very, very close to unity suggests that it will. The problem is, in fact, the opposite one to the one the top article suggests. CO_2 increase should produce a locally linear (globally logarithmic) response in terms of average temperature from some very simple physics. This is the simplest possible a priori assumption, one that ignores everything else BUT CO_2 and its direct effect on the climate. This is why, in fact, climate scientists hold so adamantly to their conclusions about anthropogenic global warming.
However, the climate is not simple, and not linear. The big question is, how well does the available data support the (very strongly held, initially) prior assumption of a simple linear independent effect for CO_2?
That’s what the data above pertain to. They suggest that the explanation for the 1983-1998 temperature increase is not CO_2 not because it isn’t a simple explanation, but because as the data clearly indicate that the problem has more complexity, that the climate is a function of more than one thing, and that the other things are capable of producing effects as large as the one attributed to CO_2 in the particular set of years indicated in circumstances where CO_2 is not a possible explanatory factor.
That is, we need a more complex theory, not a simpler one!
A vastly more complex theory, because we know (again, based on sound, strongly believed prior assumptions) that the climate is determined by the solution to a dynamical system we can conceptually define at the microscopic level but that is almost incomprehensibly complex at the macroscopic level — a set of coupled Navier-Stokes systems driven by a highly erratic set of forcings and with multiple coupled energy reservoirs with an array of pertinent time constants. Frankly, the notion that the system is linearizable in a single parameter, or a single parameter plus simple feedbacks, is and always has been absurd. We actually know the physics here, and it is not at all simple! It is arguably the most complex problem we’ve ever tried to solve. Occam’s Razor is the exact opposite of the thing needed, but our attempts to date to solve the physics problem in GCMs have met with empirical failure at almost every level it is possible to fail at. The best that can be said of them is that they produce something that looks like climate evolution, while having almost zero predictive value. It isn’t even clear that the existing models aren’t divergent where the climate is empirically enormously stable (or rather, broadly bistable or multistable with two primary attractors, a warm phase interglacial and cold phase glacial in the current orbital-geological configuration).
So sorry, I appreciate what you are trying to say and agree that the data call into question the assertion that CO_2 is solely or even mostly responsible for the single 15 year long stretch of warming visible in the latter half of the 20th century, but rejecting the CO_2 hypothesis isn’t a matter of Occam’s Razor, it is a matter of the data suggesting that the solution is a lot more complex than CO_2 alone can explain.
rgb

As already stated, Occam’s razor is a statistical generality. It does not apply to any specific problem. Occam’s razor will not reveal the location of lost aircraft. That does not mean that it is useless, such as the behavior of criminals being analyzed by detectives. Engineering uses “simpler” solutions to problems all the time.
As for “natural variations” being the cause of changes in atmospheric CO2, there are some people who know that the atmosphere is of biological origin. The atmosphere has evolved, and continues to evolve as a part of the global biogeochemical carbon cycle.
Atmospheric CO2 follows biological respiration at all time scales, with some lags due to pool sizes, ocean turnover, etc.
On longer time scales, abiotic factors also apply, such as plate tectonic changes to ocean currents and milankovich oscillations of global orbit. There may be some solar magnetic influences on biology along, etc.
Fossil fuel burning has increased the global carbon cycle by about 3 percent, which is beneficial to the ecosystems and has zero effect on Earth’s temperature.

rgbatduke says, March 22, 2014 at 7:42 am:
“In the particular case of climate science, nobody (sane) would claim that CO_2 concentration is likely to have zero effect on the climate, because a lot of physics with prior probability (determined by independent theory and experiment) very, very close to unity suggests that it will.”
Wow. That’s quite an (implicit) accusation! So you actually have to be ‘insane’ to claim that ‘CO_2 concentration is likely to have zero effect on the climate’?!

GregK says:
March 22, 2014 at 7:07 am
Occam’s Razor is not necessarily the shortest way to the truth.
It is much more pragmatic.
It means that If competing hypotheses are equally valid you should use the simplest one because it is the simplest.
Using the simplest hypothesis is tidier….and is probably, but not necessarily, more correct
In science There is no Truth, only a (hopefully) ever improving model of reality. Occam’s Razor is itself a model of reality based on an empirical observation of the scientific process. History has shown that the overturning of scientific consensus often results in a new theory that is simpler and more elegant than the old. This observation is the motivating impetus for the belief that the current Standard Model in physics is incomplete and will eventually be overturned by a more elegant “theory of everything”.

Leprechauns tampered with that too
Conspiracy theorists commonly disregard Occam’s razor in order to keep the “theory” alive by adding more and more complexity to the theory. Consider the original “CO2 contributed warming theory” compared to the “CO2 control knob to CO2 induced feedbacks and net confounding processes and “forcings” that have conspired to produce the observed GAST and undoubtedly dangerous future warming theory” of today. CAGW is a conspiracy theory.

Skeptics don’t have to explain how.
Skeptics only have to point out it isn’t what is claimed in the theory.
It isn’t a CO2 control knob, if we are to believe the data.

Occam’s Razor tell me that the is no difference between “Climate Science” and a religious cult. Thou believeist, or thou does not. If thou believeist, thou shalt find evidence everywhere, else not. I just wish the warmists wouldn’t measure temperatures the way my grandfather keeps his golf score.

my usual off topic comment!
noticing this a lot, the comments on climate topics are becoming very cynical.
just read http://www.rtcc.org/2014/03/20/climate-adaptation-facing-funding-crisis-warn-un-officials/
the comments are a treat,

lgl says:
March 22, 2014 at 8:13 am
Jeff Patterson
I agree the integrative effect is important but I don’t quite see how that will supply the necessary energy without some amplifier. NPI/NAO or other could perhaps do the trick through changing the cloud cover.
No is amplification required as long as the net effect is zero over time. Think of it in terms of an interference pattern, where a lagged, passive response is added to a cyclical forcing. Sometimes they will add constructively and sometimes destructively because both the forcing and the lag are themselves changing over time.

to me it is akin to someone telling me that the last deposit into my back account on the 3rd of this month came from someplace other than SS, see the direct deposit has been in effect since i started getting it and has been there every month so i see nothing different now than any other month, but some try to say NO it wasnt SS this time it was co2 that caused that deposit!
we have seen NOTHING unusual in the temperature record so no need to hunt for anything unusual since the climate is doing what it has always done.

Harvard University-
http://acmg.seas.harvard.edu/people/faculty/djj/book/bookchap7.html
Examination of the long-term temperature record in Figure 7-2 may instill some skepticism, however. Direct measurements of temperature in Europe date back about 300 years, and a combination of various proxies can provide a reliable thermometer extending back 150,000 years. From Figure 7-2 (second panel from top), we see that the warming observed over the past century is actually the continuation of a longer-term trend which began in about 1700 AD, before anthropogenic inputs of greenhouse gases became appreciable. This longer-term trend is thought to be caused by natural fluctuations in solar activity. Going back further in time we find that the surface temperature of the Earth has gone through large natural swings over the past 10,000 years, with temperatures occasionally higher than present ( Figure 7-2 , second panel from bottom). Again, fluctuations in solar activity may be responsible. Extending the record back to 150,000 years ( Figure 7-2 , bottom panel) reveals the succession of glacial and interglacial climates driven by periodic fluctuations in the orbit and inclination of the Earth relative to the Sun. From consideration of Figure 7-2 alone, it would be hard to view the warming over the past 100 years as anything more than a natural fluctuation!

I should add, GE, at one point the world’s largest company (may still be), supplies many (if not a majority) of the wind turbines in use in the US, probably world-wide. If that isn’t a vested financial interest, then there is no such thing.
Indeed, Magma, your ignorance is the only thing astounding in your post.
Mark

Henry Clark says:
March 22, 2014 at 1:58 am
1998-now trend = -0.050 K/decade (cooling)**
Contrast to the article’s table!
The article said nothing about 1998 to now. It said:
1975-2009 35 years and 0.161 which was significant.
This was from the interview with Phil Jones so it would have been based on Hadcrut3 at that time.

richard says:
March 22, 2014 at 9:18 am
Well said. The post below gives a rather nice summary of Global temperature variations over a range of geological periods. CO2 does not get a look in.
http://wattsupwiththat.com/2014/01/25/when-did-global-warming-begin/#more-102114

But remember that Occam’s Razor is a model selection tool for deciding between two equally feasible theories, not a model validation tool for proving correctness.
The converse of Occam is:
“For every complex problem there is an answer that is clear, simple, and wrong.” – H. L. Mencken
Simply apply Einstein’s Dictum to mediate between these two:
“Man soll die Dinge so einfach machen wie möglich – aber nicht einfacher.” (Make everything as simple as possible, but not too simple!)
😐

lgl says:
March 22, 2014 at 5:43 am
Richard It wouldn’t, but natural variation is just a description, not an explanation imo. You have to explain how.
lgl,
We don’t have to explain. The null hypothesis holds. If you need conjecture, go ask the village idiots that profess to be climatologists.

@Eric Worrall

Yes – but in the absence of compelling evidence that the more complex theory is a better explanation for observed phenomena, the more complex theory must be rejected.

I don’t buy your must be rejected. So Einstein made his theory more complex to account for relativistic effects, but we don’t “reject” Newton’s theory. It was all we needed to get our astronauts to the Moon and back safely. Both theories are useful, and both are “as simple as possible” in their respective realms.
😐

milodonharlani says:
You’ve mistranslated Einstein. “Einfacher” means not “too simple”, but “simpler” or “more simple”, implying than need be.

I paraphrased the German. Don’t we all agree that a theory that is “more simple than need be” is “too simple”?

@milodonharlani
>why not just translate the statement literally…?
Because it needed Occam’s Razor: :-]
“more simple than need be” ==> “too simple”

rgbatduke says:
March 22, 2014 at 7:42 am
“Occam’s Razor isn’t an absolute rule of reason, because sometimes the actual explanation is, in fact, the more complex of two hypotheses. That is, nature itself is not obligated to be “simple”.”
Thank you Prof. Brown; your explication of Occam’s Razor using Bayesian reasoning is very well-argued, expressed clearly, and provides a viewpoint that is “something that I can believe in”! One question though. . . when you write: “Bayesian scientific reasoning . . . deals with Occam’s razor not in verbal terms . . . , but in terms of using incoming data to recompute the prior probabilities.” Shouldn’t the end of this sentence read “. . . posterior probabilities”?
BTW, your post gave me reason to find and scan through Jaynes’ book that I had downloaded ~15 years ago and selectively read in support of a specific project. Relooking at it this afternoon, I see there’s much more to learn that I missed (or have forgotten). . . and fortunately, now that I’m retired I have the time. A great book, others may find it both interesting, stimulating, and a valuable resource.
Thanks, for another great post.
Dan Backman

Magma says:
March 22, 2014 at 7:34 am
——
What multiple lines of evidence?
Whenever someone has to scream that the other side has to be ignored because they are associated with people I hate, you know that they have already lost the argument.

Jeff Patterson says:
March 22, 2014 at 7:53 am
—-
To some people, correlation must be causation.
It’s gotten warmer.
CO2 has increased.
Therefore CO2 caused the warming.

@milodonharlani
> It’s not the comparative ending that implies
> “than need be”, but the logic of the statement.
If Einstein had said “Make everything as simple as needed, but no simpler” then I would agree with you. “Man soll die Dinge so einfach machen wie noetig – aber nicht einfacher”
But the phrase he used, “make simple as possible” (einfach machen wie moeglich), does not convey the notion of minimally required simplicity. So, (are we allowed to criticize Einstein?) he should have made this notion of ‘necessity’ more clear by saying “too simple” instead of “simpler”.
Hence the motive for my paraphrasing: “Man soll die Dinge so einfach machen wie moeglich – aber nicht zu einfach”
IMHO!

Wow. That’s quite an (implicit) accusation! So you actually have to be ‘insane’ to claim that ‘CO_2 concentration is likely to have zero effect on the climate’?!
In comparison to an otherwise identical atmosphere with no CO_2 at all? I think so. The radiative coupling of CO_2 in the LWIR bands that dominate Earth temperature radiation is an established fact. The absorption and re-emission of thermally emitted LWIR energy from CO_2 in its absorptive bands by the atmosphere is a direct observational fact, verified by numerous TOA and BOA spectrographs.
What is at issue is two things. One is the marginal effect of additional CO_2 once the atmosphere is well past the point where it is effectively optically opaque in the CO_2 bands with a comparatively short mean free path for optical photons in those bands (compared, especially, to the distance from the Earth’s surface to the heights where the atmosphere becomes exponentially transparent to the radiation). The second is the coupled effect of nonlinear stuff in the atmosphere to that marginal effect — positive and negative feedbacks. It is IMO moderately unlikely that the negative feedback from what is almost certainly going to be a positive partial derivative of global temperature with respect to CO_2 concentration is going to completely cancel the positive contribution or override it with all other things equal on average although the Earth is a chaotic nonlinear system and is capable of being kicked out of orbit around a warm phase attractor by at least some trajectories created by transient positive gain from CO_2. It is certainly possible that marginal changes of CO_2 concentration could for some comparatively short periods of time have no discernible effect on the climate because of lucky cancellations, but it is not certainly not “likely”.
To put it yet another way, AR5 persists in wanting to attribute over half of the latter 20th century warming to CO_2 with “high confidence” in spite of having no defensible quantitative basis for making any claim of confidence for any particular fraction of warming. I agree — and I think most people who understand the radiation physics agree — that CO_2 has had some effect (whether or not it is “anthropogenic” or the largest effect humans have hand on the climate). I agree that the effect is probably relative warming, but the probability here is lower — there are plausible arguments that suggest that natural feedbacks cancel the bulk of any direct warming — and it is very difficult indeed to know how to partition any climate shift into CO_2 linked change and everything else, because change is strongly coupled and because we have no method to predict what the temperature would have been outside today if there had been no increase in CO_2.
At the moment, AR5 and increasing numbers of papers are dropping the most likely effect by the end of the century to be no more than 2.5 C, and a surprising number are down now to under 2 C total warming (simply because there hasn’t been any warming at all in the 21st century). The longer it stubbornly refuses to warm, the lower CO_2 linked climate sensitivity should be, in Bayesian terms.
rgb
I

Jeff Patterson says:
March 22, 2014 at 7:33 am
“As such, the amount of energy contained in the ocean is sensitive not just to the TSI, but to asymmetry in the TSI.”
—————————–
With regard to asymmetry in TSI and its effect on ocean temperatures I would recommend this marine biology related paper –
http://www.biblioteca.uma.es/bbldoc/tesisuma/1663844x.pdf
Figure 3.(d) has plots showing power of the higher solar frequencies compared to ocean depth in w/m2. These are the frequencies that vary most between solar cycles. UV-A is shown as still providing 10 w/m2 at a depth of 50m.

Occam’s razor does not tell us anything about what is true. It tells us the most efficient way to look for what is true. The fewer assumptions, the simpler the experiment required to test those assumptions. Also, assumptions that cannot be tested are useless. Experiment tells us what is true — at least to the extent that we are able to identify the variables involved.

The fallacy here is that CO2 impacts can never be demonstrated because there will always be something be some climate/ocean chemistry variation that was hotter, colder, wetter, drier in the geological record.
The logic is false because this fallacy is combined with several other false assumptions to create a circular argument designed to reverse the burden of proof.
The whole is then clothed in some false scientific ‘respectability’ using a inverted reference to Occam’s Razor.
It turns the burden of proof upside down. We know by theory and experiment that CO2 acts as a heat trapping gas.
We know that global radiation in is greater than radiation out.
We know that the global ice mass balance is dropping. We know that most of the world’s glaciers are reducing in depth and moving uphill. We know that the earth’s oceans are gaining heat. We know that thousands upon thousands of terrestrial and marine species are changing their range and are also changing their phenology. We know that global sea levels are rising. In other words, all the things you would expect with increased heat are occurring.
(And puhlease don’t give me atmospheric-temperatures-are-steady meme as if it is terribly significant in the global heat budget).
Of course, CO2 forcing is on top of natural drivers, so we are getting, as we would expect, some ups and downs there and there.
Knowing from laboratory experiments that CO2 is a heat-trapping gas, what Occam’s Razor really means in this case is that you would have to demonstrate that the current climate variations are driven solely by natural drivers.
You can’t.
It is why Skeptic Memers are forced to keep talking about things like it has all happened before, it is undersea volcanoes, it is cosmic rays, it is natural cycles, it is clouds and the like without ever being able to demonstrate that their meming delivers anything like a global ‘natural’ heat budget unamplified by CO2 forcings.

climatease, where did you go to school, or university? Clouds trap heat reflected from the earth. That is why frost doesn’t form if it is overcast, and temperatures drop dramatically at night in desert areas. The ice caps are not melting, sea ice does come and go, and undersea volcanoes and ocean currents do control with other variables our climates. Non of these can be controlled by humans. Pollution can be controlled though, but it costs money. And if you research water vapor is the biggest component of Greenhouse gases. We can not control the weather and that is what kills us, not CO2, plus volcanoes, tsunamis, earthquakes, floods, and hurricanes and cyclones, just to name a few. Then there is the bubonic plagues, small pox, Spanish flu, AIDs that kills or has killed millions, plus wars of course. But what has CO2 got to do with this? Be interested in your answer. Just remember 75% of our air we breathe is nitrogen, 21% Oxygen, 3 % CO2, and 1% is trace gases. So we are nitrogen junkies eh?
Depends on your education, political views and life’s experience to spot a con. I am an environmentalist, but I am not a Vegan or vegetarian, but I lean towards free range meat etc., non GM vegetables etc., and have a Diploma in Organic Agricultural production (Australia). Plus two degrees majoring in Archaeology and palaeoanthropology and Ancient history. Sustainability is very important, and this does not include solar or wind power. It is growing our food for starters and combating life saving diseases. Plus trying to combat extreme weather events.

…to be sure temp rises are driven by the Sun, whats interesting is that CO2 levels will rise as a consequence. The Modern Maximum which began around 1900 heated the Earth but ended around the year 2000 so CO2 levels could drop below 400ppm now that the New Minimum has begun.

L Smith
The true utility of AGW is that it alters a suite of global risk proposition. The fact problem is by how much, when, for how long, where and who will wear the consequences, good and bad.
There is no utility in sticking the head in the sand and the bum in the air.
There is no utility at all in ignoring the actual and/or potential consequences of CO2-forced changes to ocean chemistry, ocean heat and ocean currents.
Nor is there any utility at all in steadfastly ignoring possible consequences of range and phenology variations of thousands of species, including pathogens and other pests.
For a single example of the devastating consequences of a single range extension of single species, check out Dutch Elm Disease.

Martin says:
March 22, 2014 at 12:28 am
From the article that Eric Worrall linked to:
D – Do you agree that natural influences could have contributed significantly to the global warming observed from 1975-1998, and, if so, please could you specify each natural influence and express its radiative forcing over the period in Watts per square metre…..
Surely this is assuming right at the start that the changes were not geological or biological ones. This is the problem with all climate studies that they assume the changes are the ones they can make research grants from. Anyone with eyes can see that looking at the NASA sea anomaly data there are huge five degree plus anomaly local heat sources dotted around the world with particular emphasis on the areas where warming is greatest. Thermodynamics laws preclude any global cause for higher temperatures barring a giant heat pipe taking sea water from the equator to the poles.
Money needs to be transferred from atmospheric studies to the two other possible causes and also include historical departments to look for examples of climate information in reliable historical documents. In short they would receive a 75% cut in their budgets if the job of climate studies is to be done in a balanced way.

Climatease: If you feel my academic qualifications have no bearing on my judgements of AGW protesters like you, then you are way off the mark. But troll if you like, I don’t care but I know my judgements are supported through not only learned science but also on paleaoclimatology. As
soon as I knew Michael Mann was basing his argument on dendrochronolgy (study of tree rings) I knew he could not be right in his hypothesis and hockey stick. Tree rings indicate the growth of the tree. And there are times when a tree doesn’t grow well, because of environmental causes, one being lack of rain. If the tree rings are close together, the tree has a normal annual growth.This is good for the tree and it has nothing to do with Co2 increasing, the tree does this itself. But the primary reasons for this growth are not an increase of CO2 as the tree will normally transpire this anyway. It is because the conditions for this tree were favorable for its growth. I can’t understand you don’t agree with this? And then connect it with CO2 that is a natural transpiration of a tree or plant.
Years ago, hospitals would pull out flowers from wards, because they feared it would increase C02 in the wards. They have stopped that now.
Cheers
Patricia from Oz

I agree entirely with Worrall’s piece. For a simple, transparent forecast of the timing and amount of the coming cooling based on the obvious 60 and 1000 year quasi- periodicities in the temperature data and the use of the neutron count as the best proxy for trends in solar “activity”
see several posts at
http://climatesense-norpag.blogspot.com
The abandonment of the Ockham’s Razor principle is the fundamental error which vitiates and invalidates establishment climate science.

“which was clearly caused by Anthropogenic CO2 seeing that natural influences during that period had a cooling effect!” This makes about as much sense as saying, “because a twig was broken it was clearly caused by a bigfoot”.

Don’t mean to nitpick but…a better statement of Occam’s Razor is “The preferred explanation is the one with the fewest number of assumptions that still explains all observations.” This is not always the ‘simplest’ explanation. We should seek simplicity and distrust it.

The classical example is Galieo’s and Copernicus’ ellipses with the sun as a major point, rather than the epicycles of the Greeks. You can get there with epicycles, but the math is a lot simpler with elliptical orbits. All you are doing is effecting a transformation between co-ordinate bases from anthropcentric to heliocentric – a fact that the Church understood and Galileo did not.
His insistence on the truth content of his theories was what got him into trouble, and rightly so.
While I agree with much of what you say, this particular part of your otherwise admirable essay is piffle. You should stick with the “classical example” part of the assertion. Ptolemy’s model as you say worked. It nevertheless suffered from several problems, only one of which was causality per se. The bigger problem was that it was impossible to build a meaningful causal model from the explanatory model. It was basically an amplification of Plato’s “ideal” causal mechanisms, motion in invisible spheres that formed some sort of firmament, but every time a new observation was made — e.g. moons of Jupiter — a new set of “spheres” and epicycles had to be added to what was supposedly (as always with philosophers) a “perfect” system. Ptolemy’s model fails multiple tests for knowledge in the modern sense and is an excellent example of the dangers of creating unfounded mathematical models of physical phenomena. There I think we agree.
However, you do Galileo a serious disservice when you allege that Galileo had no reason to think that his (really the Copernican) model was superior to Ptolemy’s geocentric epicycle model. Note that neither of them was a theory as that would have to wait for confirmatory evidence from the observations of Brahe and mathematical treatment of Kepler and and explanatory physical model that required the invention of physics itself by — Galileo and Newton (and various others).
Note that Galileo had already made personal observations that deduced the existence of the gravitational force, had determined that the gravitational force was proportional to the mass, and that it produced identical acceleration of distinct masses (all from observations of the oscillations of candelabra in a library as their candles burned down, timed with his own pulse). He lacked only two things needed to complete the invention of physics well before Newton — Descartes’ analytic geometry (that formed the basis of calculus) and the work of Brahe and Kepler that was proceeding in the background even as his persecution by the church proceeded and ultimately made the entire argument moot long before Newton. There is no reason at all to imagine that he did not understand gravitation well enough to have postulated that it was the cause of heliocentric orbits, although he was of course unable to prove this.
What Galileo might have achieved, or published, if it were not for the inquisition prosecuted by Cardinal Saint Bellarmine and his subsequent muzzling under house arrest, a broken man, we will never know. What we do know is Bellarmine’s agenda, as it is beautifully preserved in his letter to Galileo. Basically, the church’s official position was that the Earth was the center because the Bible Says So, and any demonstration to the contrary was a demonstration of the fallibility of not only the Bible, but every one of the supposedly divinely inspired saints and holy fathers that agreed with the mistake!
It was, in other words, a conceptual clash that opened the door to disbelief. If the Bible is fallible in one place, why is it infallible somewhere else? If our belief that it is divinely inspired truth fails in one place where we can actually check it, how can we trust it elsewhere where it cannot be so easily checked? Bellarmine was right to fear Galileo’s assertions. They were the beginning of the ongoing end of hegemony of the Catholic Church as a dominant political force in Europe and the world. It forced the church to successively narrow its assertions of infallibility to where they are now so narrow that they can never again be falsified by evidence — they are pure statements of myth and magic or events that supposedly occurred in the remote past and were documented decades to centuries later that no one can ever test.
There is nothing, in other words, noble about the Church’s stance in this. Under no circumstances is it a good thing to use direct force and the threat of mortal sanction to interdict the honest assertion of or search for the most reasonable set of personal beliefs. The Church wasn’t defending “truth” — it was defending its position of political and economic power, a position that it had only because it had established itself as the sole judge of metaphysical and physical truth via a document true, as Bellarmine noted ad litteram, not as some sort of metaphor, a document that could be contradicted only at the cost of losing the entire game, yielding all of this authority and power, for the rest of human history.
There are frightening parallels between this entire controversy and the modern controversy over the climate. The GCMs have taken on the role of the Bible — CAGW is the prediction of the infallible “physics based” models, a kind of punishment for the sin of being wealthy and enjoying the many benefits of electricity and easy, cheap transportation. The prescription of the church of CAGW for the sins of mankind is a return to austerity, a time when individual per capita consumption of energy was a tiny fraction of what it is today, simply because there are no plausible substitutes capable of providing sufficient energy to maintain the standard of living across the globe (let alone improve it) that are currently technologically feasible. That or a massive human die-off, which some warmists have shockingly enough actually asserted as a good thing (as long as the die-off doesn’t include them, of course, but so far being a warmist doesn’t seem to involve giving up driving or airplane flight or electric lights or heat or the internet or imported clothing or modern medicine serviced by all kinds of electrical equipment dispensing drugs synthesized with mined raw materials and energy or the right to have children. At least not involve them giving these things up.
rgb

How exactly would one test and potentially falsify the theory that “Natural Variability” explains recent climate?

No I have no African background, the nearest I came to Africa was a visit to Cairo in1962. I’m English 100% with a little sprinkling of Irish

According to the raw HadCRUT data that Phil Jones used to refer to the 1910 to 1940 warming in his BBC interview, there was more than +0.15 C warming per decade during those 31 years. If we only look at 1910 as the starting point (- 0.496 C), and 1940 as the ending point (+0.018 C), we get +0.514 C of warming between those two years. That’s +0.166 C of warming between 1910 and 1940 in particular, which is more than the +0.15 C that Phil Jones indicated, and more than the 1975-2009 rate of warming (+0.161 per decade) as well.
http://www.metoffice.gov.uk/hadobs/hadcrut4/data/current/time_series/HadCRUT.4.2.0.0.annual_ns_avg.txt
1909 -0.536
1910 -0.496
1911 -0.554
1940 0.018
1941 0.018
But if we use 1911 as the starting point (- 0.554 C) instead of 1910, and 1940 again as the ending point (+0.018 C), we get +0.572 C of warming between 1911 and 1940, which is +0.191 per decade (30 years even), easily outpacing the +0.161 C of warming between 1975 and 2009.
There’s probably a good reason why Phil Jones decided to make 1910 his starting point instead of 1911.
Just think what would have happened had he used the 1944 HadCRUT raw global temperature as his ending point. Global mean temperatures in 1944 were +0.150 C (!).

milodonharlani says:
March 23, 2014 at 7:38 pm
“Bruno was not burned for his astronomical but his theological beliefs.”
While that was the “official” version, it stemmed from his writings that the Earth revolved around the Sun, that stars were other suns and that Earth was not the most important creation of God, as God created an infinite universe. It was demanded he abandon these beliefs and recant them but he did not so he was declared a heretic. Actually quite a good example of a higher authority using religion to cover up the introduction of a competing theory in order to prevent the actual study of that theory just in case it turned out to prove their religious doctrine wrong. Very similar to the modern authorities who deem AGW skeptics as heretics and d*niers.

Martin:
Your entire argument hinges on two volcanic eruptions during the 1975-1998 period, one of which (El Chichon), by the way, is not considered “major” (VEI >= 6). So you have just ONE major volcanic eruption. But the period 1910-1940, with essentially the same warming as 1975-1998, also had a major volcanic eruption, Novarupta, which ejected nearly three times as much ash as Pinatubo. So, since solar influence was also “about flat” during this period, one “might have expected cooling” during this period too, even more so than between 1975 and 1998. And yet, it warmed .15C/decade, virtually the same as the latter period. Without any significant anthropogenic carbon emissions. So that puts us right back on the edge of Occam’s razor. If natural variation can not only cause warming, but cause enough warming to overcome a major volcanic eruption, and still cause 0.15C warming per decade, as it clearly did in the 1910-1940 period, then natural variation is the most reasonable explanation for the more recent warming. Bazinga!
(By the way, a more complete analysis would sum the entire ejecta of all volcanic eruptions in the to periods, but you didn’t bother with that, so I won’t either. It would also quantify the “about flat” solar influence, as well as more than just “only these two natural influences”.)

HenryP says:
March 24, 2014 at 8:55 am
re: Tom in Florida says
(quoting some or other document saying that Bruno had said:)
that Earth was not the most important creation of God, as God created an infinite universe.
Henry says
That statement, whoever made it, cannot be proven
=============================================================================
The discussion was not about what is or isn’t true, it was about what Bruno believed and what he wrote. Those are the things that got him in trouble.
As milodonharlani shows ( March 24, 2014 at 12:29 pm), there were many charges against Bruno but that belief really must have pissed off the Pope. And as everyone alive at that time knew, nothing good happens when you piss off the Pope.

Henry the VIII got away with it. But of course so called Papists were plotting against Elizabeth II.
And religion has always been a point of discussion and really we have the extreme fanatics in all religions. Whereas the majority of people are law abiding and not involved. But saying humans are changing the weather is without foundation, when there are so many external forces that control the weather and climate (seasonal changes) it is laughable this argument has got so nasty. As if we were still in the middle ages.