Mike Lorrey writes- PAY ATTENTION CLIMATE ALARMISTS:
“The phrase ‘correlation does not imply causation’ goes back to 1880 (according to Google Books). However, use of the phrase took off in the 1990s and 2000s, and is becoming a quick way to short-circuit certain kinds of arguments.
In the late 19th century, British statistician Karl Pearson introduced a powerful idea in math: that a relationship between two variables could be characterized according to its strength and expressed in numbers. An exciting concept, but it raised a new issue: how to interpret the data in a way that is helpful, rather than misleading. When we mistake correlation for causation, we find a cause that isn’t there, which is a problem. However, as science grows more powerful and government more technocratic, the stakes of correlation — of counterfeit relationships and bogus findings — grow larger.”
From Slashdot: The History of ‘Correlation Does Not Imply Causation’
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From the Slate article referenced by Slashdot:
The graph below, again from Google Books, shows the shift in language that marked this change in spirit: Up until the early 1900s, causation showed up more often than correlation in the corpus; then the concepts flip. (I’ll let someone else explain why correlations have been trending downward since 1976.)
Someone please explain to the current administration that
1) wacky offensive reprehensible youtube videos do not cause the deaths of ambassadors.
2) a lack of security detail and adequate protection may, however, place them in grave danger.
Correlation is not causation.
Controlling youtube is not the answer…oh wait a minute, of course, controlling youtube is exactly the kind of solution a powerful administration would seek – control the media and you control the people. While at it, why not seek to also control the means of production (all industry) by taxing energy (CO2). Oops, been there done that, aw shucks this administration seems to be way ahead of the sheeple, they are out thinking everyone.
I have always liked the the correlation that those who drink water die. Kinda says it all.
andrew adams says:
The case for current warming being caused by CO2 does not require that it is unprecedented or unusual,…
Nonsense. Absent the assertion that current warming is both unusual and unprecedented, there is not even any need for a “case for current warming caused by CO2”. If what is happening now has happened before and is usual, there is nothing to explain, let alone support for any particular explanation.
Hence, the extremes to which the Team has gone to defend the Hokey Stick – the only purpose of which is to prove ‘unprecedented’. And hence the current focus on weather events – the only purpose of which is to demonstrate ‘unusual’ and thus force attribution to CO2.
… and stands on the physical properties of GHGs and their known existing effects on the earth’s climate.
No, it doesn’t. The net effect of GHGs on the earth’s climate is unproven conjecture, not known. This is well demonstrated by the WIDE range of magnitudes attributed to the alleged effects, all by people claiming to ‘know’ what they are. Climate sensitivity to CO2 is held to be 0C to around 8C. Known. Hah.
D Böehm,
I may not visit WUWT much but I am certainly familiar with the “null hypothesis” argument – I just don’t buy it.
For a start there are different ways of investigating scientific questions, you don’t necessarily need a null hypothesis. But even if we want one it’s silly to say there is such thing as “THE climate null hypothesis” – scientists can choose a particular null hypothesis to suit the question they want to ask. You may prefer your particlur null hypothesis, the rest of us are not obliged to accept it.
But my biggest objection is the one I stated in my previous comment – your chose null hypotheses is illogical, unfalsifiable and can’t answer the question being posed. Firstly it is based on a false premise, that if recent warming is due to GHGs it must necessarily be outside the range of that previously caused by natural factors. That simply isn’t true. Even if current conditions are not outside those seen previously in the Holocene (it is plausible that temperatures are actually higher but we don’t have good enough records to say for sure) that tells us nothing about which particular physical processes caused the recent warming – it could still be due to GHGs but your null hypothesis wouldn’t be falsified so what use is it?
I would also make the point that the distinction between “natural” processes and warming due to GHGs is not as clear as you suggest in any case. The presence of GHG gases in the atmosphere has been an influence on the earth’s climate for millions of years, billions even. It’s an entirely “natural” phenomenon. Yet somehow because we have an increase in GHG levels due to “non-natural” cause there is this virtually unsurmountable burden of proof required to demonstrate it has had an effect.
andrew adams,
You have it backward. The Principle of Parsimony warns against introducing an extraneous variable, when the Null Hypothesis provides a perfectly adequate explanation. The extraneous variable is CO2, which is not necessary to explain the current climate.
There is no scientific evidence proving that any of the warming since the LIA is caused by rising CO2. None. It may contribute a negligible amount of warming. Or not. But the evidence is missing. Thus, AGW is merely a conjecture — a conjecture that the planet is clearly ignoring.
This is the internet’s “Best Science” site; it is not a religious blog. So provide evidence to support your conjectures, or admit that your comments are based on evidence-free belief.
Also, there are other explanations that do not require the CO2 variable. Prof Richard Lindzen writes:
Finally, your personal belief can reject the Null Hypothesis. But the Null Hypothesis is part of the scientific method, a hypothesis which even climate alarmist Kevin Trenberth accepts. If you want to stick your fingers in your ears whenever the scientific method falsifies your beliefs, well, you have some company. See below.
° ° °
Thomas T, no one here claims that all climatologists are “universally damned”. Name one commentator who has said that. Name just one.
Internationally esteemed climatologists such as Prof Richard Lindzen, Dr John Christy, Dr Ferenc Miskolczi, Dr Tim Ball, and many others are routinely cited here. Only those climate charlatans who refuse to engage in fair public debates, and who refuse to share their data, methods, metadata and methodologies, are rightly castigated. Most alarmist scientists fall into that category. Why do they refuse to abide by the scientific method, with its transparency requirement? What are they hiding?
andrew adams:
At October 3, 2012 at 8:48 am you say to D Böehm,
I really, really wish warmists would learn some science instead of spouting their superstitious beliefs.
The Null Hypothesis says it must be assumed a system has not experienced a change unless there is evidence of a change.
The Null Hypothesis is a fundamental scientific principle and forms the basis of all scientific understanding, investigation and interpretation. Indeed, it is the basic principle of experimental procedure where an input to a system is altered to discern a change: if the system is not observed to respond to the alteration then it has to be assumed the system did not respond to the alteration.
In the case of climate science there is a hypothesis that increased greenhouse gases (GHGs, notably CO2) in the air will increase global temperature. There are good reasons to suppose this hypothesis may be true, but the Null Hypothesis says it must be assumed the GHG changes have no effect unless and until increased GHGs are observed to increase global temperature. That is what the scientific method decrees. It does not matter how certain some people may be that the hypothesis is right because observation of reality (i.e. empiricism) trumps all opinions.
Please note that the Null Hypothesis is a hypothesis which exists to be refuted by empirical observation. It is a rejection of the scientific method to assert that one can “choose” any subjective Null Hypothesis one likes. There is only one Null Hypothesis: i.e. it has to be assumed a system has not changed unless it is observed that the system has changed. Hence, you are plain wrong when you say to D Böehm
The Null Hypothesis is defined by the scientific method and NOT by D Böehm. It is completely logical and if it cannot be falsified then that provides a scientific indication.
In the case of global climate no unprecedented climate behaviours are observed so the Null Hypothesis decrees that the climate system has not changed.
Importantly, an effect may be real but not overcome the Null Hypothesis because it is too trivial for the effect to be observable. Human activities have some effect on global temperature for several reasons. An example of an anthropogenic effect on global temperature is the urban heat island (UHI). Cities are warmer than the land around them, so cities cause some warming. But the temperature rise from cities is too small to be detected when averaged over the entire surface of the planet, although this global warming from cities can be estimated by measuring the warming of all cities and their areas.
Clearly, the Null Hypothesis decrees that UHI is not affecting global temperature although there are good reasons to think UHI has some effect. Similarly, it is very probable that AGW from GHG emissions are too trivial to have observable effects.
The feedbacks in the climate system are negative and, therefore, any effect of increased CO2 will be probably too small to discern. This concurs with the empirically determined values of low climate sensitivity empirically obtained by Idso, by Lindzen&Choi, etc..
http://www.warwickhughes.com/papers/Idso_CR_1998.pdf
http://www.drroyspencer.com/Lindzen-and-Choi-GRL-2009.pdf
Therefore, the man-made global warming from man’s emissions of greenhouse gases (GHG) could be much smaller than natural fluctuations in global temperature so it would be physically impossible to detect the man-made global warming.
Indeed, because climate sensitivity is measured to be less than 1 deg.C for a doubling of CO2 equivalent, it is physically impossible for the man-made global warming to be large enough to be detected (just as the global warming from UHI is too small to be detected). If something exists but is too small to be detected then it only has an abstract existence; it does not have a discernible existence that has effects (observation of the effects would be its detection).
To date there are no discernible effects of AGW. Hence, the Null Hypothesis decrees that AGW does not affect global climate to a discernible degree. That is the ONLY scientific conclusion possible at present.
Richard
JJ,
Absent the assertion that current warming is both unusual and unprecedented, there is not even any need for a “case for current warming caused by CO2″. If what is happening now has happened before and is usual, there is nothing to explain, let alone support for any particular explanation.
I would say that the current warming is unusual, even if “unprecedented” would be too strong a claim (of course that entirely depends on what timescale – there is a precedent for pretty much anything if you go far back enough).
There has cetainly been a strong warming trend over recent decases and the claim that there is “nothing to explain” is a bit odd given that many are people are arguing over exactly what the explanation is. There are good reasons to believe it is due to our GHG emissions and there are good reason for wanting to know if that is the case. So what if climate changed for different reason in the past, no-one said it can only change for one reason.
The net effect of GHGs on the earth’s climate is unproven conjecture, not known. This is well demonstrated by the WIDE range of magnitudes attributed to the alleged effects, all by people claiming to ‘know’ what they are. Climate sensitivity to CO2 is held to be 0C to around 8C.
Well we know the greenhouse effect increases the surface temperature by about 33C for a start so that is proof that GHGs play a significant role in the earth’s climate. There are no credible estimates of climate sensitivity anywhere near either 0C or 8C.
Andrew Adams
I owe you an apology. I conflated your post with another and attributed to you things which you did not say. I apologise.
That will teach me not to flip between blogsites without keeping track of where I am.
Thomas T: the problem we have here is that there appears to be no correlation between changes in co2 concentration and changes in temperature. Indeed since 1959, when the first reliable estimates of co2 were obtained from Mauna Loa, changes in co2 lag behind and not ahead of changes in temperature. However, the more fundamental problem is that the temperature series and the co2 time series are fundamentally different in nature, the first has one unit root and the second two. What that means is that no meaningful correlation can be established between the two. This has led to a number of attempts through optimal fingerprinting studies to determine some relationship but they have failed to fully establish a link because, as Hasselmann (1979) noted the results only have significance if all the forcing are known. Have a look in IPCC(2007) appendix 9 for a brief summary of the fingerprinting method but go back to the original literature on the technique to understand how shaky the results actually are.
If there was a clear statistical link then many of the arguments would have long disappeared and, indeed, the feedback problem would be relatively easily solved. Imagiine how easy it would be if (say) a lagged regression demonstrated that there was an unambiguous correlation between change in temperature and change in co2 the previous year (say) with an r2 of 0.5. This would demonstrate that 50% of the variance in temperature was attributable to changes in co2. Given the physics that would be pretty convincing. But there is no such relationship and it is very easy for anyone with a modicum of statistical skill to check it out.
It is this lack of empirical association which has forced climate science into the arms of the modellers and they have really done a poor job of retrodicting temperature changes and time series with any reliability. So without correlation the case for any causation is weak and when the casual models are, in their turn, so weak, one does begin to wonder if the core paradigm in climate science is as cut and dried as so many would like to claim.
andrew adams says:
“There has cetainly been a strong warming trend over recent decases…”
No stronger than prior warming episodes, when CO2 was much lower.
And:
“There are no credible estimates of climate sensitivity anywhere near either 0C…”
Wrong again. Dr Ferenc Miskolczi, who knows more than you or me about the subject, states that the effect of 2xCO2 is 0.0ºC. Planet Earth appears to agree with him.
andrew adams:
At October 3, 2012 at 1:40 pm you assert to JJ:
I gave you links to independent empirical studies obtained by Idso using 8 different methods and by Lindzen & Choi from ERBE satelite data
http://www.warwickhughes.com/papers/Idso_CR_1998.pdf
http://www.drroyspencer.com/Lindzen-and-Choi-GRL-2009.pdf
Those very credible studies each determine climate sensitivity of ~0.4 deg.C for a doubling of climate sensitivity.
However, as you say, there are no credible higher values for climate sensitivity although the climate models each use a different value that is much too large to be credible. Kiehl assessed this
(ref. Kiehl JT,Twentieth century climate model response and climate sensitivity. GRL vol.. 34, L22710, doi:10.1029/2007GL031383, 2007)
and his Figure 2 showing the range of climate sensitivity and how it is compensated (i.e. fudged) by assumed aerosol forcing can be seen at
http://img36.imageshack.us/img36/8167/kiehl2007figure2.png ]
Richard
richardscourtnety,
Hypotheses don’t magically come into existence of their own accord – scientists have to formulate them. And when formulating a null hypothesis the scientist has to decide on a proposition which is both falsifiable and, if falsified, provide an answer to the particular question the scientist wants to address.
Now you say first of all –
Null Hypothesis says it must be assumed the GHG changes have no effect unless and until increased GHGs are observed to increase global temperature.
Well OK, that doesn’t seem unreasonable, but we not only have both increased GHGs and increased temperatures, we also have the proven existence of the greenhouse effect, so therefore ISTM that the notion that adding GHGs to the atmosphere will not increase temperatures has been falsified, even it doesn’t in itself tell us if all of the recent observed warming has been due to GHGs, or how much warming we might expect in future.
But you claim otherwise. You say
In the case of global climate no unprecedented climate behaviours are observed so the Null Hypothesis decrees that the climate system has not changed.
But hang on, where did the word “unprecented” come from? That wasn’t in your hypothesis. You said “no effect”, not “no unprecedented effect”. Why does the effect have to be unprecedented? Where in the hypothesis that adding GHGs to the atmosphere will cause warming does it say that it must cause warming which is without precendent? That’s silly – as I said above nothing is uprecedented if you look back far enough and we know that there are factors other than GHGs which can cause warming.
Your argument about climate sensitivity would have much more weight, if it were actually true that “the feedbacks in the climate system are negative” and that CS had actually been measured to be less than 1C. But it’s not and it hasn’t, and Lindzen and Choi certainly doesn’t demonstrate that. I mean come on, even Lindzen admitted that paper was flawed.
Here is a weird correlation:
Everytime Aaron Ramsey scores for Arsenal, someone very famous dies the following day. (or in less than 24 hours)
Ramsey scores v Utd, Bin Laden dies. Ramsey v Spurs, Steve Jobs dies. Ramsey v Marseille, Gaddafi dies. Ramsey v Sunderland, Whitney Houston dies.
http://uk.answers.yahoo.com/question/index?qid=20120212003800AAVAGq6
http://www.dailymail.co.uk/news/article-2101478/When-Arsenal-player-Aaron-Ramsey-scores-famous-dies.html
Do you want something weirder? Ramsey just scored less than an hour before. Will somebody very famous die tomorrow?
D Böhme,
No stronger than prior warming episodes, when CO2 was much lower.
Which doesn’t contradict my point since I never said that temperatures couldn’t increase for reasons other than CO2.
Wrong again. Dr Ferenc Miskolczi, who knows more than you or me about the subject, states that the effect of 2xCO2 is 0.0ºC. Planet Earth appears to agree with him.
I would say planet earth very much disagrees with him. If it were true it would mean that either CO2 is not a greenhouse gas (falsified by observations) or that changes in radiative forcing could never result in changes in climate (falsified by observations).
andrew adams:
I have been thinking about your post at October 3, 2012 at 1:40 pm and I think I may have discerned your difficulty. You say
Absolutely right. However, the effect of atmospheric CO2 as a GHG is not linear. Each doubling of CO2 in the air has the same effect as the previous doubling. Therefore, the effect of increasing atmospheric CO2 from present levels has little effect.
The GHG occurs from absorbtion of radiation (i.e. IR) in the atmosphere. A sheet of paper covering the window of a room also absorbs radiation (i.e. visible) so darkens the room. An additional sheet of paper absorbs more radiation so darkens the room some more. The addition of a tenth sheet makes little difference from the darkening of nine sheets. Similarly, adding more CO2 to the existing atmosphere makes little difference to the GHG.
Also, the existing climate system responds to increased GHG to oppose effects of that increase; i.e. the feedbacks are negative.
Richard
andrew adams,
Among other things, it is clear that you still do not understand the Null Hypothesis.
The Null Hypothesis is the statistical hypothesis that states that there are no differences between observed and expected data. Wake me when you get your head around that definition.
Here you can see that the long term warming trend is decelerating [the green line]. There is no recent acceleration of global temperatures. This is based on empirical data.
Give up on the alarmist blogs you have been reading. This is the internet’s “Best Science” site. After a few months here, the scales might fall from your eyes. Not likely. But possible.
andrew adams says:
October 3, 2012 at 1:25 pm
@D Böehm,
[ , , , ]
But my biggest objection is the one I stated in my previous comment – your chose null hypotheses is illogical, unfalsifiable and can’t answer the question being posed. Firstly it is based on a false premise, that if recent warming is due to GHGs it must necessarily be outside the range of that previously caused by natural factors. [emphasis by JW] That simply isn’t true. Even if current conditions are not outside those seen previously in the Holocene (it is plausible that temperatures are actually higher but we don’t have good enough records to say for sure) that tells us nothing about which particular physical processes caused the recent warming – it could still be due to GHGs but your null hypothesis wouldn’t be falsified so what use is it?
[ . . . ]
– – – – – –
andrew adams,
There is a false premise in your above argument. Your false and hidden premise is that there is an established ‘a priori’ environmental concern about some posited alarming problem caused by the mere existence of anthropogenic CO2 in the earth-atmosphere system even if the problem is not discernible in the null hypothesis case based on natural variability. In other words you falsely introduce a hidden premise that there is some mythical environmental ‘a priori’ problem for the earth-atmosphere system even though it is behaving like a historical earth-atmosphere system with only non-anthropogenic CO2.
Your approach is somewhat irrelevant to the scientific discourse per se.
NOTE: Your false and hidden premise is the fundamental pre-condition for the initial UN justification for the establishment of the IPCC . . . . so you are not alone. : ) You have a lot of environmentally emotional support, but little actual objective scientific support, within the IPCC.
John
andrew adams says:
“There has cetainly been a strong warming trend over recent decases…”
The warming trend was ONLY during a period from 1970ish-1998 which was part of the NATURAL cycle. (And mostly due to urban land tempertures and data adjustments)
The coincidence of tempertaure and CO2 trend during that SHORT period is ONLY coincidence , (assuming you discount deliberate data tampering), NOT correlation and certainly NOT causation.
If CO2 drove warming, it would have warmed between 1940-1970 and from 1998 until now.. BUT IT DIDN’T. So the hypothesis that CO2 forces warming is demonstrably FALSIFIED !
@ur momisugly Robin Melville
I learned that in many cases churches did cause pubs. It used to take a long time and a lot of men to build a church. While it was being built, some smart operator would set up a pub nearby to provide liquid sustenance to the workers.
After the church was built, the same establishment would provide relief for the victims of the long, tedious, sermons.
If there was a clear statistical link then many of the arguments would have long disappeared and, indeed, the feedback problem would be relatively easily solved. Imagiine how easy it would be if (say) a lagged regression demonstrated that there was an unambiguous correlation between change in temperature and change in co2 the previous year (say) with an r2 of 0.5. This would demonstrate that 50% of the variance in temperature was attributable to changes in co2. Given the physics that would be pretty convincing. But there is no such relationship and it is very easy for anyone with a modicum of statistical skill to check it out.
Well said.
I have yet to see any correlation between CO2 change over some period and temperature change over some period, and where CO2 leads temperature that is more than trivial.
And at the risk of reigniting rcourtney, the absence of correlation is proof of the absence of causation, bar chance and one other exception (one or more other causative factors operating in the other direction to CO2), which is the main argument (using fiddled aerosol forcings) used by AGW advocates as to why we don’t see a correlation.
andrew adams says:
I would say that the current warming is unusual, …
Yeah, but you’re the guy who just got done saying that ‘unusual’ wasn’t necessary to your case. You say lots of things. Talk is cheap.
There has cetainly been a strong warming trend over recent decases …
And recent centuries, and recent millennia – though we don’t appear to be above the peaks of similar timeframes. Yawn.
… and the claim that there is “nothing to explain” is a bit odd given that many are people are arguing over exactly what the explanation is.
Many people are arguing, often quite violently, over the will of Allah. This does not demonstrate the existance of that deity. You seem to have difficulty discerning belief from reality.
There are good reasons to believe it is due to our
GHG emissionstransgressions against the flying spaghetti monster and there are good reason for wanting to know if that is the caseFunny how that still works.
So what if climate changed for different reason in the past, no-one said it can only change for one reason.
Crops may fail for more than one reason, therefore THIS one is surely due to witches!
Well we know the greenhouse effect increases the surface temperature by about 33C for a start …
By what means do you think we ‘know’ that?
… so that is proof that GHGs play a significant role in the earth’s climate.
That is not the question before us. Whether GHGs play a specific, unproven conjectured role is. You are handwaving.
There are no credible estimates of climate sensitivity anywhere near either 0C or 8C.
Says you. You say a lot of things. Saying things is easy:
There are no credible estimates of climate sensitivity near 4C
See.
andrew adams:
At October 3, 2012 at 1:32 pm I took the trouble to explain the Null Hypothesis to you. That explanation included these statements:
and
At October 3, 2012 at 2:15 pm you reply to that saying:
That is a complete non sequitur.
As I explained to you SCIENTISTS DO NOT FORMULATE A NULL HYPOTHESIS : they assess how to determine if and how the null hypothesis is falsified by a change.
If you persist in ignoring answers provided to you and parroting errors that have been refuted then it would seem your purpose is disruption of – and not involvement in – dialogue.
Richard
Philip Bradley:
At October 3, 2012 at 8:26 pm you write
No need to “reignite” me. I am still waiting your offer for the bridge. I remind that at October 3, 2012 at 1:11 pm quoted you having said to me at
October 3, 2012 at 5:37 am you say to me
And I replied
My sampling is good because it is a random selection from bridges in the real world which cross the Thames, so – as you assert – there is no chance involved in accepting my offer.
It is a very good bridge and I am willing to accept a very cheap price.
Richard
AndyG55 says:
October 3, 2012 at 2:32 am
Bob Ryan says:
October 3, 2012 at 2:01 pm
In fact, the correlation is evident across the entire modern CO2 record.
Hi Bart: I am not sure what your point is but coincidence on a graph is not correlation. Before establishing correlation we need to ensure that the two time series are stationary. Correlation without stationarity is quite meaningless. Stationarity is simply the property that the mean and variance are constant and any perturbations in the trend are mean reverting. Without stationarity in the data any correlation is likely to be spurious. Have a look at http://www.duke.edu/~rnau/411diff.htm for a straightforward explanation.
The proper way to deal with this is to transform the two time series to attempt to induce stationarity before testing for correlation. Working with various data sets including this one I have hit the same problem that statisticians and time series modellers have discovered – determining correlation has proved very difficult. Hence the the attempts to resolve the problem through more sophisticated multivariate techniques as reported in AR4 s12.
To be clear, I have little doubt that co2 is a forcing in climate change to some degree. However, tracking down its significance and the extent to which it is attenuated or magnified by other factors is where the real issues lie. I also have no doubt that the absence of correlation does not necessarily mean absence of causation – the former is a statistical concept, the latter is a physical one. Strong correlation is a strong clue that causality between variables is present but given the number of independent variables in play in the climate system the absence of correlation says nothing about causality one way or the other.