The 'correlation is not causation' hockey stick

I like Go Home’s correlatons. Great.
ThomasT – Logic, does not seem to be your strong suit.
As you head back to the safety of your Church of CAGW remember that those hoofbeats behind you are probably not from zebras, horses, or bison. The are from the sensible, scientific bloggers on WUWT.
Open your mind please. The Alarmists have taken a short term correlation of global temperatures and rising levels of CO2, and extrapolated them with computer models that made forecasts/predictions that never came true.

D Boehm says
D Böehm on October 2, 2012 at 9:23 pm
Thomas T,
Positive feedbacks have been falsified by Planet Earth; the ultimate Authority. Believe what you want, it isn’t reality. CO2=CAGW is a debunked fantasy.
————–
Simply saying that positive feedbacks don’t exist isn’t good enough. Putting words in Natures mouth isnt a convincing argument either. It’s very likely you don’t understand positive feedbacks and how they apply to climate.

richardscourtney says:
October 3, 2012 at 3:45 am
You cannot pretend that ‘chance’ may be “absent”, and that is why your assertion is plain wrong.
Chance for the purposes of this discussion is a function of sampling. It is not a property of the real world.
Chance is absent from the real world.

“(I’ll let someone else explain why correlations have been trending downward since 1976.)”
The answer to this is fairly simple. With the information/computer/Internet revolution, we have seen an insane explosion in available information. Frankly, humans are not yet capable of dealing with the information overload. The reduced use of the word “correlation” reflects our inability to relate these large amount of diverse data. It is, in other words, an indicator of our psychological state of mind, in which uncertainty is growing and making sense of the world is increasingly challenging. This trend also explains why people have become increasingly ideological–they cling to simplifications (not guns and religion!) to make the world more manageable.

Philip Bradley says:
October 3, 2012 at 3:18 am
Which is chance. Note I said ‘absent chance’.
—
Which is of course the kicker.
It is impossible to prove whether your correlation is real, or the result of chance.

Now the burning question is- do ice-cream sales affect swimming pool drownings or vice-versa?
If eating ice cream were known to cause, say, stomach cramps that increased the likelihood of drowning, then correlation would be intuitive toward causation. But there is no intuitive link, and so your example is weak.
Whereas, for over a century CO2 has been known to be a greenhouse gas.

michael hart,
One accusation that could be levelled at the mentality of the hockeystickers, is that they are not very good at imagining alternative explanations to account for observations. Eliminating incorrect hypotheses is, in fact, the bedrock of the scientific method.
Sure, but suppose we have a hypothesis which is based on well understood physical mechanisms, which can’t be eliminated, is consistent with our observations and indeed predicted them in advance. Suppose the obvious alternative hypotheses have been examined and can’t account for observations. Suppose no one has so far put forward an alternative hypothesis which is actually supported by hard evidence. How much time, effort and resources are we supposed to devote to looking for alternative explanations which are unknown in nature, whose existence is entirely speculative, and which are certainly not required to exist? And if we at the point where we are looking for “unknown unknowns” then how will we ever know we have eliminated all possible alternatives? Surely there comes a point where we have to accept that we have an explanation which works well enough to be at least provisionally accepted?
Now I’m not suggesting that we stop trying to improve our knowledge of the way our climate works, people are indeed still doing this and no doubt there are still gaps in our knowledge which will hopefully become smaller with time. But there is no particular reason to assume that this will lessen rather than increase the case for recent warming being caused by human GHG emissions.

The classic example of spurious correlation was provided by George Udny Yule, a Past President of the Royal Society and a colaborator of Karl Pearson in the development of statistics.
A study of Church of England marriages betrween the years 1866 and 1911 showed a coefficient of correlation of +.95 with standard deviation of only .014 when measured against the standardised mortality of 1,000 in England and Wales. Thus providing clear evidence that marrying in church increased the risk of death.
Actually, as Udny Yule pointed out, both series were reducing over the whole 45 year period and the only signifcant correlation was between each series and time.
While there is evidence that human activity contributes to warming (e.g. UHI) and there is also evidence that human activity adds to CO2 levels, the correlation between any increase in CO2 levels and warming may well be spurious. (I am aware of 150-year old laboratory experiments but I am also aware that what works in a lab experiment more often than not does not translate well inot nature.)
Both series (if measurable) are correlated directly to increasing numbers in the world population and to the increasing average wealth of that world population. Even if all energy were to be provided by “renewables” human activity would still contribute to warming so long as either or both the numbers and wealth of the world population continued to increase.

Graph against temperatures please.

Apologies to D Böehm for misspelling his name.

Andrew Adams,
We know that the Earth experienced warming without any assistance from CO2 during the Medieval Warm Period, the Roman Warm Period, the Minoan Warm Period, the late Holocene Optimum and the Early Holocene Optimum. Therefore alternative explanations of warming ARE required to exist. The most likely cause of the current warming is some combination of the factors which caused the previous warmings and it would be a very good idea to research them. There is no shortage of candidate explanations, which don’t have to be mutually exclusive, the most prominent being ocean oscillations and cosmic rays.
Your assertion that computer models based on the CO2 hypothesis match observations and, in fact, predicted them, is jaw-dropping. The models can only be made to match observations retrospectively by continually introducing post-hoc parameter adjustments and fudge factors such as aerosols. The models wildly exaggerate warming, principally because they get the magnitude and sign of water vapor feedbacks wrong. Hence the need for aerosols to dampen the warming from predicted to actual levels.
We know that the warming effect of CO2 is logarithmic and that the IPCC says that a doubling of CO2 will produce a temperature rise of 3.3 degC (central estimate). Therefore, a rough and ready estimate of the effect of CO2 can be obtained as follows :-
3.3 = X ln(2) therefore X = 4.76
The atmospheric concentration of CO2 in the late 1800s is alleged to have been 278 ppm and it is now 398 ppm. So, since the late 1800s we should have seen a temperature rise of around
4.76 x ln(398/278) = 1.7 degC
from the effects of CO2 and associated feedbacks alone. To this should be added any warming from natural causes, urban heat island effect and dodgy data adjustments by climastrologists. Instead, we have only had warming of 0.8 degC including natural causes, UHI and dodgy adjustments. Doesn’t this make the models look a tad shaky ?

Nothing observed today is unprecedented or unusual.
Nonsense. The rapidity is unprecedented. The role of human contributed CO2 is unprecedented.
It has all happened before
Not with this rapidity and human contribution.
and to a greater degree
Not in modern human history.

Thomas T
The rate of warming during the periods 1860-1880 and 1910-1940 was 0.16 degC per decade, the same as in the period 1970-2000. Phil Jones of the CRU has admitted that there was no statistically significant difference.
Although there were not enough thermometer-based weather stations prior to the mid-1800s to allow a global mean temperature to be calculated, the Central England Temperature record is a thermometer-based record extending continuously back to 1659. This indicates that temperatures rose during the period 1695-1735 at more than 3 times the above rate.
I’m afraid the claim that the recent rise in temperatures is unprecedented is bovine faeces.

Anyone claiming that a Null Hypothesis (not just climate-related, but ANY Null Hypothesis) is illogical and unfalsifiable has absolutely no understanding whatsoever of science or the scientific method.
Of course, given the quality of schooling in much of the world these days, it doesn’t surprise me that many people don’t understand what a Null Hypothesis is and why it MUST be used as a baseline in any scientific discipline….
Another thing that highly annoys me is the claim that “Anthropogenically Produced CO2” is somehow NOT part of “natural variability”.
When a beaver builds a dam, it isn’t somehow “unnatural”, now is it? When man builds a dam, this is not in any way “unnatural” either.
As the great band Love & Rockets once sang,
“You cannot go against nature, because when you do… go against nature, that’s a part of nature too!”
Nothing that man does is “unnatural”. It is PHYSICALLY IMPOSSIBLE to do something “unnatural”. Everything that man does can be accounted for by physics, and anything “unnatural” would violate physics.
As such, any CO2 we are adding to the atmosphere IS ACTUALLY part of “natural variability”. It is possible to ASSUME the the level of CO2 in the atmosphere would be different in the absence of natural human actions, but that just proves that natural human actions are a part of natural variability. However, it is also possible to hypothesize that the increase in atmospheric CO2 is the direct result of more CO2 being released from the oceans as they naturally warmed, and as the oceans again undergo their natural cooling cycles, they will begin to absorb more CO2, thus reducing the atmospheric concentration. If this does occur, then it will be increasingly difficult to quantify the human contribution. Sure, we can get a pretty good estimate of how much CO2 our activities RELEASE into the atmosphere, but what we release into the atmosphere through our activities doesn’t really seem to “hang around” in the atmosphere for very long, so it is very difficult to quantify what the “natural” level of CO2 in the atmosphere “should” be right now.

djake – you have it right.
The relative effect of water vapor = 33,000 ppm * 90 percent = 29,700
The relative effect of CO2 = 380 ppm * 8 percent ~ 31 – or about 1/970 that of H2O, which establishes beyond any doubt that CO2 effect on climate is infinitesimal.
And that’s before we consider the ratioo of man’s activities to CO2 activity (probably less than 1/1,000 of total CO2 activity – also infinitesimal.
So in total you have 1/(970*1,000) as the effect of human activity on climate i.e., about a million to one odds against it. An infinitesimal of an infinitesimal.

Thomas T has been shown to be wrong over and over and over on multiple threads. He refuses to acknowledge any of it, and continues to spew his nonsense. We are supposed to accept him at his word when he says things like “Nonsense, the rapidity is unprecedented”? Who is the d-nire here?

Someone correct me if I am wrong, but do not see any rabid rapid responders on this thread belonging to Cook’s Crusher Crew from Paranoiaville (CCCP***). If there is anyone commenting on this thread from CCCP then would you kindly self-identify in the name of the intellectual integrity of the Cook blog venue?
***any correlation to the acronym of the former Soviet Union is amusingly just coincidental and not intended. : )
John

Thomas T reveals his ignorance of the subject once more:
“The rapidity is unprecedented.”
Wrong.
The fact that CO2 has been rising steadily without any acceleration in natural global warming indicates that any effect from CO2 is so small that it cannot be measured. And if it cannot be measured, AGW is only a conjecture.

dcfl51,
My remark about not requiring alternative explanations related to modern warming, not past warm periods. For those clearly alternative explanations are needed and no one denies there are known factors other than GHGs which can cause warming, they just don’t explain the warming in recent decades. I’m not sure why you think that highly speculative and unproven theories about ocean oscillations and cosmic rays are a more plausible explanation that GHGs.
I said nothing about climate models or how they compare to observations – you certainly don’t need a model to predict that increasing GHG levels will cause warming, you don’t neccessarily need them to make a rough estimate of how much warming to expect. Still, your claims about models overestimating the warming do not allow for the difference between transient and equilibrium sensitivity, you overestimate IMHO the effect of UHI and remarks about dodgy data adjustments are just cheap shots. Also, you say we have to allow for “natural warming”, but how do you know the net effect of natural factors has not been negative rather than positive? Having said all that, let’s accept for argument’s sake that the observed warming is a bit lower than expectations – why does that logically mean that the warming we have seen is not due to GHGs? Surely it would be more of a problem if there had been more warming than expected?

http://drtimball.com/2012/environmentalists-create-another-false-claim-about-climate-change/

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.

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.

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:

The notion of a static, unchanging climate is foreign to the history of the earth or any other planet with a fluid envelope. The fact that the developed world went into hysterics over changes in global mean temperature anomaly of a few tenths of a degree will astound future generations. Such hysteria simply represents the scientific illiteracy of much of the public, the susceptibility of the public to the substitution of repetition for truth, and the exploitation of these weaknesses by politicians, environmental promoters, and, after 20 years of media drum beating, many others as well.
Climate is always changing. We have had ice ages and warmer periods when alligators were found in Spitzbergen. Ice ages have occurred in a hundred thousand year cycle for the last 700 thousand years, and there have been previous periods that appear to have been warmer than the present despite CO2 levels being lower than they are now. More recently, we have had the Medieval Warm Period and the Little Ice Age. During the latter, alpine glaciers advanced to the chagrin of overrun villages. Since the beginning of the 19th Century these glaciers have been retreating. Frankly, we don’t fully understand either the advance or the retreat….
For small changes in climate associated with tenths of a degree, there is no need for any external cause. The earth is never exactly in equilibrium. The motions of the massive oceans where heat is moved between deep layers and the surface provides variability on time scales from years to centuries. Recent work suggests that this variability is enough to account for all climate change since the 19th Century.

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?

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.

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.

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?

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

@ 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.

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 emissions transgressions against the flying spaghetti monster and there are good reason for wanting to know if that is the case
Funny 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.

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.