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## Occam's Razor sez Eric Worrall is a science denier

Sou | 2:38 PM

Anthony's took the day off so he allowed one of the nuttier nutters to run the nuthouse at wattsupwiththat.  Eric Worrall has posted an article at WUWT (archived here).

Eric is arguing that Occam's Razor disproves the greenhouse effect.

Oh Eric didn't say that in so many words, but applying Occam's Razor to his simple thought processes suggests that is the case.  For example, this is the crux of Eric's argument:
... if we reject the principle of Occam’s Razor, we open the door to accepting theories of arbitrary, ultimately infinite complexity. A theory created by researchers who do not accept the principle of Occam’s Razor cannot be falsified, because the theory can always be tweaked in arbitrary ways to avoid falsification.
So why does applying the principle of Occam’s Razor force us to reject the theory that anthropogenic CO2 is the main driver of contemporary climate change? The reason is that nature has produced periods of warming similar to the recent warming, without any significant contribution from Anthropogenic CO2.
So we have two competing hypothesis for what is driving contemporary climate change:-
1. Observed natural variation, which has produced periods of warming statistically indistinguishable from the warming which ended in 1998.
2. Observed natural variation + an unproven assumption that Anthropogenic CO2 is now the main driver of Climate Change.

Eric just made it up out of thin air that there are "two competing hypothesis".  There aren't.  Science shows that CO2 is a greenhouse gas and that when it's increasing like it is now, then Earth will get hotter, like it does now.  He is also wrong about his notion that a theory "can always be tweaked in arbitrary ways to avoid falsification".  There is a limit to how much a theory can be modified in the light of new evidence.  If the basis of a theory is completely wrong, the entire theory will eventually break down and be discarded.

Eric concludes:
Clearly the second hypothesis fails the test of Occam’s Razor. In the absence of compelling evidence that anthropogenic CO2 has overridden natural variation, we have to accept hypothesis 1 – that observed climate change is the result of natural variation.

Now there are a few things wrong with that logic.  First it doesn't follow that CO2 must "over-ride natural variation" for all the rise in temperature to be attributable to natural variation.  All that is needed is to show that natural variation does not account for all the changes to climate.

Secondly, climate change is much more than a rise in global surface temperature.  There are what is known as fingerprints of climate change, which indicate the cause.  One of these is the temperature change in the stratosphere compared to the troposphere.  Both are measured.  Because the stratosphere is cooling, it shows that the warming troposphere is caused by the build up of greenhouse gases.  Eric doesn't mention that inconvenient fact, probably because it conflicts with his own hypothesis. As Eric says, the simplest explanation is the most likely.  I'll add the caveat that whatever the explanation, it has to fit with the evidence.

Thirdly, we don't "have to" accept anything but the evidence that supports the theory.  We have a choice.  We can choose to be like Eric and other deniers of science and reject the science and take pot luck about the consequences of that decision.  Or we can accept the evidence and the associated explanation and make informed decisions.

Lastly, there is evidence that CO2 is increasing.  It's been measured.  Toward the end of the video below, you'll see just how much CO2 has built up over the past 800,000 years:

And, of course, scientists have been able to work out and explain quite clearly what has contributed to global warming and by how much. Click the chart to enlarge it.

 Source: IPCC AR5 WG1 Fig. TS7.1

### The simplest explanation

Occam's razor suggests a hypothesis when it comes to Eric Worrall, based on his article and his history.  I know he's read HotWhopper and I know he's been visiting lots of different climate blogs, those that write about science as well as those that reject science and/or promote pseudo-science.: He actively rejects science.

The reason for him actively rejecting science could be any and quite possibly all of the following:

1. He wants to curry favour with the denialati.
2. He suffers motivated reasoning because of his ideology.
3. He doesn't understand science.
Supporting evidence is that Eric Worrall has even looked to stock market indicators instead of science to argue the world is about to cool.

johnmarshall says:
March 22, 2014 at 4:23 am
I go along with that. Good post many thanks.

Village Idiot points out the idiocy using a simple logical fallacy and responds to Martin (who tried to bring science into the mix):
March 22, 2014 at 1:03 am
Martin: You’ve entirely missed the point of the good Professors piece. Bringing stuff like data, facts and physical laws into the mix, just making it more complex.
Let me try to again explain the simple beauty of the argument:
It’s been as hot or hotter as it is now during the last millions of years (without human emissions) therefore humans have no influence on climate now.
Try a bit harder. It’s really just a matter of faith ;-)

Roy complains that there needs to be a grade school primer sent to him personally, because he's incapable of doing his own research using Google, and says:
March 22, 2014 at 2:19 am
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?

Frederick Davies says:
March 22, 2014 at 2:36 am
Great (and more importantly, clear) post.
FD

lgl asks Eric and inconvenient question and says:
March 22, 2014 at 2:39 am
Fine, but what is the ‘simplest explanation’ for the 1880-1998 rise?

cedarhill says he's not about to let facts get in the way of his science denial, or something:
March 22, 2014 at 3:09 am
Facts are not a deterrent in the warmist political campaign. After all, how many Americans under the age of 30 are not aware the Earth circles the Sun? Regardless, facts and logic are still fun things.

AlecM is a greenhouse effect denier who makes up his own "physics" and says:
March 22, 2014 at 4:09 am
No truly professional engineer or physicist agrees with the central premise of the ‘enhanced greenhouse effect’, the assumption that the Earth’s surface emits to the atmosphere net real IR energy as if it were a black body in radiative equilibrium with absolute zero.
This juvenile mistake, predicting three times intrinsic CO2 warming, is from incorrect physics taught in Meteorology and Climate Science. It is our era’s equivalent of the 18th Century’s ‘Phlogiston’, also debunked when real scientists did real experiments. The analogy is apposite because Phlogiston was supposed to be a 5th Greek Humour, emitted from heated bodies!

1. Watch out, Sou! You misspelled Eric Worrall twice by leaving off the last "l". Eric seems to feel very strongly about this issue, because after I misspelled Crichton and corrected myself, he noted that "Misspelling to insult opponents is an old game in the Climate fraternity."

Eric is able to say this while calling me a "JPL climate seantist" which can't be an insulting misspelling. Otherwise it might seem like there are two different sets of rules, or a nonzero amount of hypocrisy in the air.

I've been trying for months to find time to debunk Eric's repetitive accusations about GRACE which he regurgitated from WUWT and falsely attributed to JPL. It's hard to find the motivation to do this after Eric refused to stop accusing me (and my colleagues) of killing poor people, refused to stop comparing us to Nazi eugenicists, and is blackmailing humanity:

"You can’t ignore us – because we can and will stop you from implementing solutions you favour, unless our conditions are satisfied.

We don’t believe there is a problem – so it is you who has to come to us. I don’t like coal, but I don’t fear it the way you do.

See it as blackmail, with the future viability of the ecosystem at stake, if you will – but work with us, or watch our deadlock destroy your world.

[Eric Worrall, 2013-04-25]

1. Still claiming JPL were wrong about problems with their Grace satellite DS?
:-)

http://wattsupwiththat.com/2012/10/30/finally-jpl-intends-to-get-a-grasp-on-accurate-sea-level-and-ice-measurements/

2. Yet again: No, Eric. That’s not what JPL believes. You’re just regurgitating WUWT’s absurd claims and falsely attributing them to JPL scientists like me. Again, I’ll try to respond when I can find the time.

3. Thanks DS, fixed spelling.

4. Here is a link to the original government document reference by the WUWT post on problems with the pilot project GRACE - and the need for GRASP, to produce accurate measurements.

I will however accept the possibility that JPL were exaggerating the problems to try to solicit more funding, if that is your perception of why such a document was written.

5. Continued paranoid accusations just lower my motivation.

6. Make an effort DS - maybe you hold a minority opinion that Grace data output is better than the tragic state described by the document?

7. Science is a minority at WUWT, which innocently "interprets" tragic states while accusing alarmism.

8. At least we don't make up fantasies about regime changes, and try to claim our hypothesis is "settled science", without any evidence that anything has actually changed.

9. Eric writes
"Here is a link to the original government document reference by the WUWT post on problems with the pilot project GRACE"

Um, did you even read the document you linked. It did not state at all that there were problems with GRACE. The GRACE mission has in fact proved to be a great success, and has provided data 100 times more accurate than previous data.
https://directory.eoportal.org/web/eoportal/satellite-missions/g/grace

The link you provided was to the 'next-generation' of satellite to enable a sub-mm Terrestrial Reference Frame (TRF). Using the current range of technology, the current accuracy is about 1mm, which in itself, when you think about it, is an amazing feat of engineering and science. The GRACE satelites are already way past their designed lifespan, and so an update and replacement, with better technology and better accuracy is needed. But you and Watt's totally misrepresented it. You seem to have a petulant vendetta against DS, by continually bringing up old and tired retorts.

Eric, you are a classic dilettante. Using the same tired memes and a long list of logical fallacies and misrepresentations. In the depths of the depravity that is WUWT, you can get away with that sort of foolish behaviour, but in real life, where there are many people who are far more knowledgeable than you, you come across as an highly arrogant and concieted silver-tounged fool who is obsessed with proselytising.

Look, you are fighting against over 150 years of science, all of which says that you and your ilk are wrong. Instead of voicing your inner Morton's Daemon, and looking like a imbecile in the process, how about this. Actually do some reading about the science, instead of lambasting it.

To be frank, there is no amount of misrepresentations or logical fallacies that will change my mind. I'm going to let you on in a little secret. If you actually want to be successful as a science communicator, you actually need to provide supporting evidence, in the form of published papers. I know you think that the ECS is about 1C, so provide a paper that shows that the ECS is around 1C, and you might actually make a dent. Instead you just 'assert', by closing your eyes and wishfully thinking. I mean just think about it for a moment. Our society has already increased CO2 by about 40% and for that, the temperature has increased by about 0.85C. What on earth makes you think that the warming will be only 1C, when we are almost already there. It just doesn't make sense. Also what makes you think that the earth's sensitivity has suddenly decreased, when dozens of studies shows that the ECS is very unlikely to be 1C or less.
http://www.nature.com/nature/journal/v491/n7426/full/nature11574.html

Ooh, do you see that. I linked to an actual published paper to support my argument. But I know what you are thinking. "Ahh, Nature magazine, another biased alarmist publication", but that is your Morton's daemon speaking. To most of the population, Nature and other similar publications are highly respected journals. It is only you and the Watties who live in some sort of Bizarro world, with conspiracy theories and alarmists at every turn.

It's about time that you finally grew up and stop fighting against reality. Stop roaming the internet looking for blogs that you hate and then trolling them. It really is callow and indecorous.

"...One of these is the temperature change in the stratosphere compared to the troposphere. Both are measured. Because the stratosphere is cooling, it shows that the warming troposphere is caused by the build up of greenhouse gases. ..."

Spoken like the stratosphere is well understood. But as this NASA article on the unexpected collapse of the Thermosphere shows, there is still a lot to learn about what drives atmospheric inflation and contraction.

As for alleged attribution of climate change to various forcings, I will find that a lot more credible when climate scientists pin down climate sensitivity to a reasonably tight range of values, rather than the embarrassingly broad range currently embraced.

So we can either pretend the science is settled, as Alarmists like yourself do, or we can look at the facts. There is nothing unusual about the recent warming which ended in 1998, in the context of previous warmings, and there is nothing unusual about the current global temperature.

There is no need to add an assumption that anthropogenic CO2 is driving global warming to explain recent climate change. Recent change is indistinguishable from climatic shifts which occurred in the recent past, before anthropogenic CO2 could have had an impact.

1. Stop blaming NASA for your misinformation campaign, Eric. Look up the heat capacity of the thermosphere vs. the stratosphere (or more relevantly, the surface + mixed ocean layer) and think about why medical doctors don't measure patients' temperatures at their fingertips.

A scientist could examine the trends and uncertainties to see if they support the notion that recent warming somehow ended in 1998. A contrarian wouldn't bother. I've even given you open source code that you could've used to learn that uncertainties are always larger for shorter timespans. My reward was yet another lecture about Nazi eugenicists.

Since you continue to falsely attribute your civilization-paralyzing misinformation to NASA, maybe you should explain why climate.nasa.gov says "climate-warming trends over the past century are very likely due to human activities".

2. NASA can say what they like, what they can't do is offer credible evidence that current climate trends are different to what came before humans added significant CO2 to the atmosphere.

As for the pause, denying the pause is so last year - even Michael Mann has joined the list of people who grudgingly admit the possibility that the pause is real, and not simply an artefact.

3. Eric writes: "I will find that a lot more credible..."

I call bullshit on that. Applying Occam's Razor to Eric's past articles and comments shows that his rejection of science has nothing to do with science itself. As long as climate science shows that humans are affecting climate and earth systems generally, Eric will protest it - though most of the time (as in this case) he doesn't even know what it is he is protesting!

Eric is just another mediocre denier.

4. Falsely attributing your nonsense to Michael Mann is even more hilarious than attributing it to NASA. Especially so now that I said a contrarian wouldn't even bother to calculate the trends and uncertainties before claiming that global warming stopped, and none of your your comments has. It's also amusing that NASA can offer credible evidence about the thermosphere that you seem to find important, but NASA can't offer credible evidence about the surface which is where >99.999% of humanity lives.

5. I notice a rather strenuous effort to shoot the messenger this time, rather than answer my key point, that there is nothing unusual about current climatic conditions, in the context of past natural variation.

6. This is the sort of silly comment from Eric that provides evidence for my hypothesis:

"NASA can say what they like, what they can't do is offer credible evidence that current climate trends are different to what came before humans added significant CO2 to the atmosphere."

Eric doesn't say what he means by "climate trends" and my guess is he doesn't know what he means. Ergo he doesn't know what he's talking about.

I've provided the chart above that shows the contribution of the different emitted components to radiative forcing from 1750 to 2011.

Applying Occam's Razor, that is yet more evidence supporting the hypothesis that Eric rejects the physics of the greenhouse effect, despite Tyndall and all who followed in the 150 years since his measurements.

My hypothesis is that dumb Eric is not just a science denier, he's a greenhouse effect denier.

7. For some bizarre reason, the source you cite (NASA) doesn't seem to agree with your armchair conclusion. Neither does any other national science organization. Shooting the messenger who agrees with the overwhelming majority of the scientific community surely wouldn't take the form of accusing them of being "seantists" who kill poor people like Nazi eugenicists and are trying to bring about a new dark age.

Otherwise it might seem like there are two different sets of rules, or a nonzero amount of hypocrisy in the air.

8. I provided an example of what I meant in my WUWT post. The average temperature of the Earth is cooler than past epochs, such as the Holocene Optimum, and Eemian Interglacial, and recent post 1950 warming is of similar magnitude, rate and duration to pre 1950 warming (e.g. the 1860 - 1880 warming).

Since natural variation must have been responsible for the 1860 - 1880 warming, and the current temperature of the Earth is not unusual, the suggestion that CO2 is having a significant influence on global temperature is an unproven hypothesis.

There is nothing you can point to and say "there be the effect of CO2 - this cannot be due to natural variation".

9. Eric is just another mediocre denier who believes that repeating the same nonsense ad nauseum makes it true.

He claims "Michael Mann has joined the list of people who grudgingly admit the possibility that the pause is real" and links to a graphic attached to Mann's article in SciAm. An easily checked lie.

Even his linked graphic from SciAm has the label "faux pause". Hint to Eric - "faux" means fake, false, not genuine.

From the article summary
"The rate at which the earth's temperature has been rising eased slightly in the past decade, but temperature is still increasing; calling the slowdown a “pause” is false."
http://www.scientificamerican.com/article/earth-will-cross-the-climate-danger-threshold-by-2036/

10. I really need to start addressing my comments to Eric. I'm used to fending off these accusations alone, but I'm glad to see that I'm not the only one exasperated by this nonsensical onslaught.

11. DS, all I'm saying in this instance is, where is your orbit of Mercury moment? Where is your Michelson Morley experiment, which demonstrates an observation which cannot be explained by natural variation? Where is your test of a prediction, such as the apparent displacement of stars, to confirm that CO2 theory can explain phenomena which cannot be explained in any other way?

You've got nothing - admit it.

12. What a depressingly predictable re-run of last year's Worrall lecture: "Scientists of the early 20th century laid the foundations of Quantum Physics, of many modern fields of science, so they obviously knew how science should be practiced."

Since this is just a re-run, I'll wait for Eric to critique my statements on quantum physics and relativity, which he was apparently too busy to bother with the first time.

13. Like I said, you've got squat. If you had a genuine answer to my point, you wouldn't have to try to run distraction.

14. What a depressingly predictable re-run of that time in 2012 when Eric asked "questions" about predictions. After John Byatt quoted an excellent list compiled by Barton Paul Levenson, Eric showed that he wasn't interested in a genuine answer.

15. Eric, I think you're running the typical unreasonable expectation of science meme that deniers often run. Climate science has to work with variables known to varying degrees of precision. Physics generally works with only a single variable at a time, running controlled experiments or carefully planned observations. If physicists applied the same criteria as you would apply to physics, Einstein would still be a matter of debate instead of settled as far as possible in science. F = m x a is a model as much as e = mc2.

16. "DS, all I'm saying in this instance is, where is your orbit of Mercury moment? Where is your Michelson Morley experiment, which demonstrates an observation which cannot be explained by natural variation? Where is your test of a prediction, such as the apparent displacement of stars, to confirm that CO2 theory can explain phenomena which cannot be explained in any other way?"

Eric, what are you feelings in areas of science like plate tectonics, epidemiology, evolution for which there is a steady accumulation of evidence without killer experiments?

17. Sure, OK. Where is the evidence that the climate is behaving differently to the past? Climate is warming at a similar rate to warming episodes in the recent past. Global temperature is not unusually warm or cool. What is unique about current climate, in terms of observed behaviour?

18. It is unique in that all known 'natural' forcings are pointing downwards, towards cooling. It should be cooling, not warming!

19. Marco, your statement presupposes that natural forcings are sufficiently understood to make such a definitive assertion.

20. Eric Worrall: There is nothing unusual about the recent warming which ended in 1998, in the context of previous warmings, and there is nothing unusual about the current global temperature.

In other words Eric Worrall claims that the 0.8°C per century trend we have seen since 1880 is all natural variability. That would mean that natural variability is huge.

And at the same moment he claims that the minimal deviation of about 0.1°C since 1998 is a sign that global warming has stopped. That would mean that natural variability is very small, otherwise this deviation would not be significant.

This does not fit together, the influence of natural variability on trends becomes smaller the longer the considered periods are.

DS: "Since this is just a re-run, I'll wait for Eric to critique my statements on quantum physics and relativity, which he was apparently too busy to bother with the first time."

Interesting. I am also still waiting for an answer from this busy guy. At my blog he asked: "How do you know the climate didn't actually cool?" I gave him multiple lines of evidence and since he did not show up any more.

The question also does not fit to the above statement that there was (natural) warming (until 1998).

Let's hope the reader can make up his own mind about the credibility of Eric Worrall.

21. Eric, the fact that you and other active science rejectors don't understand science doesn't mean that scientists don't understand science or make observations.

If you can't even work that out then there is little hope you'll figure out what people here are telling you.

Have you considered taking up a hobby that doesn't involve making a complete ass of yourself?

22. "Climate is warming at a similar rate to warming episodes in the recent past"

No it's not. The 21 years to 1880 warmed at 0.10°C per decade, the 21 years to 2004, at 0.23°C was almost two and a half times that. The 31 years to 1940 warmed at 0.14°C per decade, the 31 years to 2005 was again significantly faster at 0.20°C per decade. Further the entire 39 period of current warming, at 0.17°C per decade is faster than either of these two earlier periods and significantly longer.

There is no analogue in the instrumental record for the current warming.

23. If your daughter's temperature normally varied up and down a tenth of a degree in a day and one week it was 98.6F and the next week it was 102F you would not say that the variations were indistinguishable. You'd try to find out what was happening.

24. O dear, this Worrall can't even distinguish stratosphere from thermosphere...

3. Eric writes.
"But as this NASA article on the unexpected collapse of the Thermosphere shows, there is still a lot to learn about what drives atmospheric inflation and contraction."

Ahh, hang on. The NASA article was talking about the Thermosphere, NOT the stratosphere. Just because there are unknown factors in the Thermosphere does NOT translate to unknown factors to the cooling of the stratosphere. This is your classic fallacy of composition or fallacy of division logical fallacy.

Eric writes.
"As for alleged attribution of climate change to various forcings, I will find that a lot more credible when climate scientists pin down climate sensitivity to a reasonably tight range of values, rather than the embarrassingly broad range currently embraced. "

Oh dear, this time the association fallacy.

Eric writes.
"So we can either pretend the science is settled, as Alarmists like yourself do, or we can look at the facts. "

And then the classic Ad hominem logical fallacy.

Eric writes.
"There is nothing unusual about the recent warming which ended in 1998, in the context of previous warmings"
And of course no supporting evidence.

This recent paper shows that you couldn't be more wrong.
http://www.meteo.psu.edu/holocene/public_html/Mann/articles/articles/SchurerEtAlJClimate13.pdf

Eric writes.
"Recent change is indistinguishable from climatic shifts which occurred in the recent past"
Again, no supporting evidence.
Be sure to read this paper to see where you are going wrong.
http://www.meteo.psu.edu/holocene/public_html/Mann/articles/articles/SchurerEtAlJClimate13.pdf

Oh dear, it seems that Eric is an expert in logical fallacies and unsupported assertions. It's what we have all seen with those who dismiss the laws of physics. They have no supporting evidence, so they have to resort to a congo-line of logical fallacies. Of course the idiots at WUWT lap crap up like that all the time, but under a critical examination, their arguments fall over like a drunken sailor!!

4. One has to be careful when wielding Occam's razor as one is likely to get cut.

Occam's razor is not an irrefutable principle of logic nor a principle of the scientific method. Complex scientific models are often supported over simple models as more data becomes available e.g. the idea that proteins carry hereditary information may be simpler but gene theory has supplanted it.

An appeal to simplicity would have meant that Newton's idea of radiation behaving like particles would have been prefered over Huygen's wave theory of radiation, and yet, neither of these models was sufficient and were replaced by the wave-particle duality of radiation theory. An appeal to simplicity via Occam's razor would have seen the Theory of Gravity reduced to "what goes up, must come down" and, amongst other things, would have ruled out a search for gravity waves.

Which means, I guess, that Occam's razor is Not Useful when applied as the criterion for selecting among competing theories or models that 'explain' the same phenomenon. [Note the 'explain']

So applying Occam's razor as has been done in the WUWT article is meaningless. And that's leaving aside the fact that natural variability alone cannot explain what is going on with the global climate. Einstein in formulating his Constraint Equations was aware that there is a limit to reducing a theory to it's simplest level and that's at the cost of losing the theory's ability to represent reality. And there's the rub.

1. Einstein's more complex theory was accepted because it explained well known phenomena which couldn't be explained by Newton's clockwork model of the Universe.

Even so, Einstein's theory was not fully accepted until he made a prediction which had never been tested - and had his prediction validated.

My point is there are no analogous unusual climatic phenomena which need to be explained. Nothing about current climatic conditions is sufficiently different from past conditions to warrant a new untested assumption.

2. "My point is there are no analogous unusual climatic phenomena which need to be explained. Nothing about current climatic conditions is sufficiently different from past conditions to warrant a new untested assumption."

Which ones do you mean? I've seen explanations in terms of insect emissions, thunderstorms, undetectable "waves" in the atmosphere and so on.

3. Eric wrote: "My point is there are no analogous unusual climatic phenomena which need to be explained."

Eric, you are repeating yourself. We get it that you despise knowledge. You're not interested in explanations. There's no need to repeat the fact you're a member of the Illiterati and "don't want to know".

And this one: "Nothing about current climatic conditions is sufficiently different from past conditions to warrant a new untested assumption."

That's about the first sensible thing you've said for a while, Eric. There's nothing new about the fact that the amount of atmospheric CO2 controls how much and how quickly Earth heats and cools. Earth isn't behaving any differently to how it did in the past under similar conditions. When CO2 increases it gets hotter. Always has and always will.

4. George is, of course, completely correct. Occam's razor is not something that should be used to distinguish between different models. It is simple a principle that should be considered when developing models/ideas. One can't simply use Occam's razor to decide to leave out radiative physics.

Here's an argument against it being natural variability. The atmosphere and land have a low heat capacity. We're 0.85 degrees warmer now than we were in the mid-1800s. If this was all natural variability that is unassociated with a radiative forcing, then this excess energy should have been lost within months or a few years. That would seem a pretty strong rebuttal to the "it's all natural variability" argument.

5. No, that doesn't follow at all.

There have been similar warmings which lasted several centuries, long before humans emitted significant CO2, such as the Medieval Warm Period, the Roman Warm Period, and the Minoan Warm Period.

Natural variation is quite capable of producing substantial warming events which last for centuries.

Then of course their is the big daddy of all the recent warmings, the warming which ended the last ice age.

6. Eric, do you know what caused those warmings? If not, you lack so much background education on climate change that you should never even be allowed to comment on the science until you do (and I mean not allowed by yourself - recognizing one's own own ignorance is what a good skeptic would do). If you do, please do try and link those mechanisms to the current warming. You'll find you miss a forcing to explain the current warming if you ignore greenhouse gas emissions. Which then leaves you with only one option as per Occam's Razor: the known science of the function of greenhouse gases must be included, and leads one, again according to Occam's Razor, that the current warming is caused by greenhouse gas emissions.

7. Eric, your theory of Occam's Razor is not convincing. You haven't shown any proof of your theory, or even a formal testable statement of it. In fact it seems like a lot of hand waving. Rather than strive to understand the Earth's radiative imbalance and the effects of CO2 and other gasses, you simply wish it would all go away.

8. David, what I have produced is two lines of evidence that there is nothing unusual about current climatic conditions:-

1. The warming between 1860 and 1880 is indistinguishable from the warming which occurred between 1975 and 1998. This is not my numbers, it is a table produced by Prof. Phil Jones of the CRU, during his interview with the BBC.

2. There is nothing unusual about current global temperature - there have been warm periods, some warmer than the present day, well before anthropogenic CO2 could have had any influence on global climate.

Nothing about current climatic conditions is unusual - therefore there is no justification for adding a hypothesis that anthropogenic CO2 is having a significant effect on global climate.

Marco, I don't know what caused those warmings. And neither does anyone else. If climate science cannot pin down something as central to their hypothesis as climate sensitivity to CO2, to a respectably narrow range of values, then there is no reason to believe that other forcings are well enough understood to make definitive statements about them.

9. "1. The warming between 1860 and 1880 is indistinguishable from the warming which occurred between 1975 and 1998. "

Wait, what?? What warming between 1860 and 1880? Remember there has been almost .5C of warming since the mid 1970's.

"2. There is nothing unusual about current global temperature - there have been warm periods, some warmer than the present day, well before anthropogenic CO2 could have had any influence on global climate. "

So? Your logic fails at a basic level. If A causes C, and we find that C has happened, that does "not" mean that A is the cause. C can be caused by more than just A. You don't accept that; for you if there has been climate change, the "only" thing that could have caused it is "natural variability", which you present as a magical causative agent you feel it unnecessary to quantify. If you are not capable of understanding such a basic tenet of elementary logic, Occam's Razor suggests you will be incapable of making an intelligent argument on climate science. This in fact is the case.

"Marco, I don't know what caused those warmings. And neither does anyone else."

Argument from ignorance. Just because *you* are too lazy to open up a book or read the scientific literature, don't assume everybody else is a lazy and ignorant as you.

10. I think Eric has fallen for the trick of Anthony Watts and Richard Lindzen, which is pretty dumb. (Surprise, surprise).

http://blog.hotwhopper.com/2013/08/bewildered-anthony-watts-has-more.html

11. Eric,
Natural variation is quite capable of producing substantial warming events which last for centuries.

Only if it is associated with a change in radiative forcing. So, increases in solar insolation could do this, but the evidence very strongly suggests that that can't explain our current warming. Volcanic influences could produce cooling that might persist. There is some evidence for unforced variability associated with ice sheet instabilities, but that can't really explain our current warming. So, unless your natural variability is associated with some change in forcing, it can't produce warming that can persist for > 100 years. Also, you then have to explain what happened to the anthropogenic forcings which are more than capable of explaining our current warming. I would invoke Occams Razor, but that would seem disingenuous :-)

12. This comment has been removed by the author.

13. Eric

1. The warming between 1860 and 1880 is clearly indistinguishable from the warming which occurred between 1975 and 1998. Between 1860 and 1880 the mean global temperature was -0.29C and between 1975 and 1998 it was +0.125C. Big difference that needs to be explained

2. What is unusual about current global temperature is the rate of change. Yes there have been warm periods, some warmer than the present day, and there are well understood reasons why they were warm. But for the current rapid rise in temperature (about 0.8C) since there is no known natural cause.

Perhaps nothing about current climatic conditions is unusual for you, but for scientists seeking to understand Earth’s climate in detail, there is lots to study. The effect of the dramatic increase in radiatively active gasses in the atmosphere in the last century is a key concern which your Occams’s theory does not address.

14. Eric,

You say

There have been similar warmings which lasted several centuries, long before humans emitted significant CO2, such as the Medieval Warm Period, the Roman Warm Period, and the Minoan Warm Period.

Well leaving aside the question of whether those really "similar warmings" and whether they actually were several centuries long, you are missing the point that one of the reasons climate has changed in the past has been due to changes in the level of CO2 in the atmosphere. Not necessarily during the periods you mention, but others such as the PETM for example.

The fact that such changes were not anthropogenic in origin is neither here nor there, the radiative properties of CO2 do not change according to where it comes from. So as Sou points out above we are not proposing some new mechanism which has not occurred in the past.

Your position is inherently contradictory - you want us to believe both that the climate is behaving as it has done in the past and that it is not.

15. "Marco, I don't know what caused those warmings. And neither does anyone else." and projection of ignorance.

Also, Eric believes in magic (the meaningless meme of 'natural variation' which of course includes the cycle of Industrial Revolutions).
Then obviously there have been bushfires before humanity so man never causes bushfires in modern times.

5. Occam's razor tells us Worrall is wrong because his hypothesis requires him to create a new body of physics to explain how a greenhouse gas is not acting as a greenhouse gas. Good old Occam, silly old Worrall.

1. If only the IPCC could nail down that slippery climate sensitivity, and, like, get a few predictions right.

2. Where are your testable predictions, Eric? And your model that explains and can hindcast observed climate change?

You have none, you say?

Ah, the wonder of the handwavers. Majick!

3. You mean the prediction that surface temperature will rise when CO2 increases - just like it has? Or that ice will melt as temperatures rise - which it has? Or the prediction that the troposphere will heat while the stratosphere will cool - which they have?

I'm not sure that it's within the mandate of the IPCC to predict whether a science denier will claim Earth is about to cool because moving averages cross.

On the other hand, cognitive science theory would predict that motivated reasoning will continue to be the root of a lot of science denial and going by the evidence here, it seems a reasonably satisfactory prediction.

I'll predict that deniers will continue to shift from pillar to post, denying the greenhouse effect one minute, then shifting away from "hypotheses" based on Occam's Razor to write gobbledegook about current climate trends. There has been scientific research on this phenomenon, which can be covered under the general heading of conspiracy theories - that is, that climate science is a hoax, which is what Eric seems to believe - when he's not believing that climate sensitivity estimates may one day be narrowed even further than they have been. (Since the earth system isn't static and will never be static, it's unlikely that there will ever be a single number assigned to climate sensitivity, not to one decimal place and not even to ten times one decimal place.)

The way Eric has been jumping around from one misunderstanding of science to the next, shifting from earth is going to cool to questions about climate sensitivity - all indicating he presumes that climate science is a hoax, this is the paper that probably applies:

http://www.sciencedaily.com/releases/2012/01/120126152134.htm

I'd predict, based on that science, that Eric will continue to jump from one denier meme to another even when they contradict one another.

4. Sou, your response to my challenge to produce some evidence that there is something unusual about current climatic conditions is to spin another unfounded hypothesis about me believing Princess Diana is alive and dead at the same time?

Do you have any evidence for your new hypothesis? Or are you just an incorrigible fantasist?

5. I provided the evidence in my comment. I guess it went over your head. And it's not my hypothesis - I provided a link to the paper which gathered evidence.

You fit the bill, being a conspiracy theorist who believes that climate science is a hoax. As for believing contradictory things - you postulated only a short time ago that the earth is about to cool because of stock market indicators. Today you ask about refining climate sensitivity, which suggests you accept that global warming is real and caused by radiative forcing from CO2. Then again in this same discussion, you argue that all this extra CO2 isn't causing the earth to warm. That's three contradictory notions right there.

6. Eric writes
"produce some evidence that there is something unusual about current climatic conditions"

Have a read of this Eric.

http://www.meteo.psu.edu/holocene/public_html/Mann/articles/articles/SchurerEtAlJClimate13.pdf

And when you have finished that

http://www.climatechange2013.org/images/report/WG1AR5_ALL_FINAL.pdf

But of course no amount of evidence will convince you. You have already shown that your ideology will continue to trump reason every time.

7. "Eric Worrall March 23, 2014 at 8:23 PM
If only the IPCC could..."

= "Look a squirrel!!!!!!!"

If you don't have a reply then don't use the 'reply' button. I'd have thought you could understand the function of the 'reply' button even if climate science is over your head.

6. Eric,

"There have been similar warmings which lasted several centuries, long before humans emitted significant CO2, such as the Medieval Warm Period, the Roman Warm Period, and the Minoan Warm Period.

Natural variation is quite capable of producing substantial warming events which last for centuries."

If you have any proof that indicates the above were Global, rather than regional warming events, I'm sure we would all like to see it. It is amazing how your lot consistently manage to blur the distinctions between the two.

7. If you have any proof that indicates the above were Global, rather than regional warming events, I'm sure we would all like to see it. It is amazing how your lot consistently manage to blur the distinctions between the two.

And, does Eric have any evidence to suggest that these were not associated with changes in radiative forcing. There is evidence to suggest that both the MWA and the LIA are associated with changes in solar insolation and changes in volcanic activity.

8. I would also question Eric's claim that the above warming events he mentions were "similar" to the current warming. See below:

http://www.realclimate.org/index.php/archives/2013/09/paleoclimate-the-end-of-the-holocene/

We have easily exceeded the temperature values of those warming events recently, so in what context can he claim they are similar?

I remember him making a "similar" claim that we have had "similar" ice loss (to 2012) in the arctic in the 1930's based on Norwegian ice maps. "Similar" to him does not mean the same as it does to us ordinary folk. The "similar" ice loss according to the maps turned out to be about around 10% to 15% less than the 20th century mean, as opposed to the 60% loss in ice extent observed in 2012 (and 80% by volume!), so not so "similar" then.

Eric is great at rhetoric and handwaving, constantly asking for hard, undeniable proof, but then failing miserably to back up his own bone headed assertions.

9. It wasn't just (natural) volcanoes and solar insulation changes, humans have been diddling climate via CO2 (CH4) changes for ~8,000 (~5,000) years ie land-use/tree-cut (rice paddies, animal husbandry).

The MWP, whenever it was and such as it was, was not entirely natural, as CO2/CH4 were higher than they would have been, absent humans.

A substantial contributor to the start if the LIA was the ~9ppm CO2 drop from 1525 to 1600AD, from human causes (50Mperson pandemic in Americas), followed by natural volcanoes and Maunder.

Bill Ruddiman's book: Earth Transformed(2013), based on numerous Peer-reviewed papers in credible journals by him and/or other researchers. Bill gave the Tyndall Lecture on this at last big AGU meeting, an honor that is not casually given.
The Earth's climate has not been entirely natural since human civilization started, and "should" have been cooling slowly with jiggles from the usual Milankovich effects. Human additions to GHGs lessened that cooling for thousands of years, with our own jiggles from plagues and wars. Of course, we have now turned the thermostat to HIGH.

1. John, indeed, I keep forgetting about Ruddiman's work. The evidence for it being some kind of unforced natural variability is, however, very weak (possibly, non-existent?).

2. I'm not exactly sure what you meant by the first "it."

I'll restate, for all:
1) As per CDIAC,has recent (slightly old) concentrations:
CO2 392 ppm (now ~400)
CH4: ~1800 ppb (see details)

2) Ruddiman, Kutzbach, Vavrus(2011)., especially Fig 2B and Fig 6, which actually don't include much of post-I.R. time, among other things because they blow out the top of the scales. From those graphs (and can compute this different ways and get similar answers):

CH4: 1CE ~570ppb,1000CE ~570ppb
CO2: 1CE ~~255ppm, 1000CE ~252ppm, 1950 ~250ppm

3) For CH4 1CE-~1900CE, see Sapart, et al(2013). Note the jiggles, but fact that instead of dropping as expected, CH4 was higher from 1000AD onward, but with sharp drop into 1600CE.
See also Mitchell et al (2011) (paywall, sorry), which identifies certain CH4 drops as likely to have been caused by wars. or plagues. LPIUH = Late Preindustrial Holocene (1000-1800CE.)
"The two biggest wars in Asia during the LPIH were the Mongol invasion beginning in 1211 C.E. lasting for about three decades, and the overthrow of Ming dynasty and the establishment of the Qing dynasty in the mid‐17th century. These events were associated with large losses of population estimated at 35 million (∼30% or ∼15% of the total Chinese or Asian population, respectively) during the Mongol invasion and 25 million (∼15% or ∼7% of the total Chinese or Asian population, respectively) ...
After razing villages and cities, the Mongol army laboriously dismantled the irrigation systems and used their horses to churn up the soil"
In the Sapart graph, note the sharp ~1200CE and ~1600CD, and that could be coincidence, but they work through the math.

4) Here's Law Dome CO2 since 1CE., being careful of scales.
CH4 (a flow) can jiggle faster than CO2 (~stock),, so they act as time filters of different durations, akin to the way glaciers of different sizes act.

5) Bottom line, from La Dome CO2 graph:, but CH4 is mostly similar:
a) We've had higher CO2 and CH4 than natural for many 1000s of years.

b) The Roman Warm Period should have been warmer than later (Milankovitch), but the higher human CO2/CH4 helped. Then plagues came, and both GHGs dropped a bit, and didn't really recover or get higher until ~1000CE, quite visible in the graphs.
The MWP, such as it was ... was human-caused, at least in part, from tree-cutting and agriculture.

c) The drop into 1600AD is quite visible, a big chunk from massive die-off in Americas and maybe some from the Asian wars. If one works through the numbers (as Ruddiman & co have), it is almost certain that most of that drop was human. Add volcanoes and Maunder and it stayed a bit cooler, especially in places like Europe, for good reasons.

d) Of course, the I.R. rise was human, especially as there is no such thing as a magic fantasy "rebound from the LIA."

e) As for the various multi-decadal/century-scale jiggles that show up in GHG records:
a) Some are likely measurement errors, always.
b) Some must be volcanoes, solar changes, ocean oscillations, etc.
c) But some are likely to be human effects
d) And jury is still out on that,
e) But neither the MWP nor LIA were completely natural.
f) The 1750AD-onward rise was mostly human.

3. Hi John,
Thanks. The "it" simply referred to the warming as measured by the instrumental record (say 1880 onwards) - I should have been clearer. I was just meaning that we largely understand what has caused past warmings and it's mostly forced. Hence there is no evidence to support that our current warming is some kind of unforced, natural variability.

I was probably too glib when I said some of the past warm periods are associated with variations in solar forcing and volcanic influences :-)

4. Well, warm periods might have been solar up, cool periods might have been solar down and/or volcanoes.

Paleoclimate attribution problems are actually pretty interesting exercises in extracting signal from noise and bounding uncertainty of what's going on, perhaps akin to astronomy, where one has some data, but can't really do experiments, but has to get better observations and more clever ways of analyzing it.

10. I know others have said pretty much the same things, but just for giggles...

Eric Worrall engaged in a logical fallacy (quite apart from any other errors of fact) that immediately renders invalid his claim in the OP. Ockham's razor suggests that Worrall is therefore not sufficiently informed in the basics of scientific thinking, and/or is insufficiently mentally competent to do engage in the basics of scientific thinking, to be able to comment with any authority on the subject of something as complex as climate physics.

Or, to say it more succinctly, an argument built on a false premise that substantively changes the conditions on which the argument is based, is wrong. As is the person who so argues.

1. ...to so engage...

(To preempt any distress that typographic errors might impose upon the subject of this thread.)

11. A related rule, which can be used to slice open conspiracy theories, is Hanlon's Razor: Never attribute to malice that which can be adequately explained by stupidity''.

From http://physics.ucr.edu/~wudka/Physics7/Notes_www/node10.html

1. The Wikipedia entry for Hanlon's Razor seems to be missing any mention of Napoleon Bonaparte, to whom is attributed:
'“Never ascribe to malice that which can adequately be explained by incompetence.”

Of course, if he did say/write that, I'd guess it was originally in French.
Google: napoleon "N’attribuez jamais à la malveillance ce qui s’explique très bien par l’incompétence."

12. I must thank Eric Worrall for providing substantial data for my study of pseudoskepticism found in the 1900 comments from the SalbyStorm.

he made 9 comments, 7 at NOVA.1, 1 each at WUWT.1 and WUWT.3.

Readers may search those to see his comments in context, and evaluate whether the some might be defamatory towards Macquarie, including repeated invocations of Deutsche Physik..

Oddly, I didn't find any trace of an apology when it turned out that Salby had been debarred by NSF for financial chicanery, had a history of intense but frivolous lawsuits that kept getting dismissed, mis-use of credit card in Oz, etc,etc ... (and there is more to come)

Anyway, thanks again to Eric, like the other ~390 dismissive commenters, he has volunteered useful data for the next report. His 9 comments in the top ~10% of commenters who were not also bloggers.

13. Maybe Eric Worrall could take Occam's Razor to 97% of the world scientists and the total small lot of deniers he belongs to, that are just a cancerous pimple on human knowledge.
He and his ilk sound almost as absurd as the young man who had the delusion he was dead! Just google ' Vilayanur S. Ramachandran'.

Bert from Eltham

14. Summing up then, EW has incorrectly summarized Occam's Razor as "the simplest explanation is the correct one". As a result, EW has had a deeply flawed article published by WUWT. Deeply flawed because, contrary to the popular view of OR as described by EW, the simplest available theory is often less accurate.

EW has, unconsciously, accepted that the simplest available theory is often less accurate with his comment: "Einstein's more complex theory was accepted because it explained well known phenomena which couldn't be explained by Newton's clockwork model of the Universe." Furthermore, if EW was to correctly apply Occam's Razor, the burden of proof is on him to provide grounds for his position that natural variability sufficiently explains 'recent' climate changes. EW has failed in that regard as his comments show that he is arguing from a position of ignorance.

1. George, I'd assert that the simplest explanation here is actually the most accurate one. Bear with me for a moment...

A consequence may have one cause, or it may have many causes. In our world the latter is very frequently the case, and I would suggest that it is the case in a majority of instances.

Now, Eric Worrall, the master coward who's suddenly disappeared now that he's being backed into the corner with respect to his bogus thinking in his WUWT piece, hasn't had the courage to address the logical fallacy on which his entire premise is based - he was affirming the consequent. That is, he was saying:

"A results in B.

B, therefore A."

which completely ignores "B, therefore C, D, E... and/or X" in addition to A.

Bad logic, bad Eric. He's completely ignoring the simplest, most parsimonious observation that there are alternative (and more likely...) causes for the consequence which so sticks in his craw - that the planet is warming.

(Recaptcha has a sense of irony - "almitti competent"...)

2. Recapchate is sentient. After I added my parenthetical comment above it said "this editso".

3. Bernard, I concur. The argument presented by EW is incorrect on more than one level. It's logically incorrect, a propositional fallacy or affirmation of the consequent. As far as EW is concerned, he'd possibly even argue the modus ponens form, "If A results in B. A, therefore B". Not withstanding, it's also scientifically incorrect and a bad effort all round.

4. I notice that Eric Worrall hasn't returned to defend his logical fallacy...

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