Friday
Feb032012
by 
Josh
Josh Cherrypicking
Feb 3, 2012 Climate: Sceptics Climate: Statistics Josh There has been a lot of blog battling and twitter twootling started by this WSJ article
with climate crossness here and here and here, all brilliantly buffed and rebuffed by Matt Briggs
A lot of the argument was about 'how to do climate graphs' with input taken from Skeptical Science.
H/t MrSean2k at WUWT who finds a rather good example.
So here is a quick lesson in how to do Climate Graphs - please concentrate.
;)
From Cartoonsbyjosh.com (click image for larger version)
Reader Comments (144)
To stand back and look at the big picture: It was warming for about 30 years until 1998 or so. Since then it hasn't warmed any more and it looks to be starting to cool down - and pretty quickly at that.
The CO2 percentage in the atmosphere appears to have been rising steadily over that period. Some of that is probably due to human influence.
The CO2 percentage has bugger all to do with the global temperature.
We didn't cause the warming and we are not causing the cooling and we couldn't control it either way even if we wanted to.
We might want to try to start making it warm up pretty soon.
The warmists might then want to start burning all of the fossil fuels they can get their hands on.
That will work - as long as you are sitting in front of the fire.
Shub
That is beyond ludicrous. Please tell everybody else to shut up too!
You botched your 'deconstruction' of the IPCC cartoon. Stop digging.
Mark T
You are letting your inner anger over other issues boil out. We have all been there, so we understand, but just stand back, take a deep breath and then read some of the comments about BBD.
I really appreciate your knowledge in signal processing. Please accept my advice in psychology. Just cool off and accept the others for what they may be and realize that you will not convert nor even teach them.
What are you talking about?
You haven't replied to any of why I said at all.
We boil at different degrees.
-Ralph Waldo Emerson
This BBD guy exists solely to make people 'boil'.
Smart people can count, and when the pages are broken into 40 comments at a time, they can do so easily.
So, what, you just stopped reading after that? Start at 2:33 a.m., since you're numerically challenged. As I told you, every one of my objections was clarified. There are only 100 or so posts so you could have easily skimmed through the posts following my objections to see that I did just that... but no, you had to be difficult.
I get the strong impression that you know I clarified my objections. You know this and cannot accept that I showed you up. Not a problem that you don't understand, but an honest person would have accepted that he was not all seeing and asked "why" after my very first post (which I also noted). You did not, but you've never done anything that indicates you're an honest person.
Mark
Shub
Of course I replied to you. From Feb 4, 2012 at 4:13 PM:
"Your deconstruction of the IPCC cartoon is deeply odd. The IPCC states that the rate of warming has increased during the C20th. So if you "go backward, including longer and longer periods of time to calculate a rate of warming, the rate warming actually goes down, and not up".
Well obviously it does."
It just looks as though you didn't understand the response. Perhaps you could read it again.
Not at all. I know all about BBD. I used to read with disgust claims people made that BBD was "truly wanting to learn, and makes reasoned points with regularity" (paraphrased, of course). At the time, I was quite certain he was not truly wanting to learn (he's always written arrogantly about things I know he does not understand), even before his "conversion." He was doing nothing but parroting what others had written, without fully understanding the implications of doing so, and without the ability to ask "why" when posed with something he does not understand.
Exposing this is a good thing. Once the echo chamber supporting the so-called scientists that are doing it wrong in the first place go away, the scientists will be forced to listen.
Converting is not my goal. Exposing.
Mark
Shub
I've been mulling over your snark about me 'shilling' for the IPCC cartoon. You might be surprised by this, but I don't entirely agree with that presentation either.
I think that while it is clear that the AGW signal begins to emerge in the mid 1970s it is far from evident that there has been a constantly accelerating rate of warming since then.
Mark
Expose away then. I can't wait. But watch the other edge on that sword.
Notice that BBD has had more than enough time to acknowledge that I did indeed address each one of my complaints (numbered 1 through 4) yet there is no apology present on this thread, not even a simple "oh, yeah, I see them now." Hmmm...
You're a charlatan. The best this board has ever been was while you were banned.
Mark
The fact that you refuse to respond is more than enough, BBD.
I dare you to address my objections rationally.
It will be difficult for you to expose anything with me in this regard - it is impossible to expose someone that is honest about his knowledge, not just with others, but with himself. I learned a long time ago that making absolute claims about things I do not fully understand is the easiest way to get myself embarrassed or even humiliated. You have not learned that lesson. Unfortunately, it is easy to simply walk away from a blog so embarrassment or humiliation are difficult to impose and your lesson will likely go unlearned.
Mark
I see. You are one of those commenters that just ignores stuff already posted if it gets in the way.
Let's try Feb 4, 2012 at 4:02 PM again:
Actually Mark, I didn't realise that comments had gone to two pages. It was indeed careless of me.
However, when I did realise my mistake and read the rest, I found very little actual substance. There was this:
Which I happily agree with. But it does not apply when averaging monthly means to annual means in a multi-decadal temperature time series like HADCRUT. You are making a great deal of noise about nothing.
Although I note the usual tactical swipes at the competence and integrity of earth system scientists. Which is why I don't take you very seriously now.
Perhaps you would like to fold up your pocket vendetta and put it away now. It's boring for me and must be worse for others.
Okay, back to business: cherry-picking.
Here are the five year means for HADCRUT and GISTEMP (global average T) and CRUTEM and BEST (surface T). And not a trend line in sight ;-)
Does the IPCC cartoon really misrepresent the evolution of global (or surface) T over the C20th?
HADCRUT
GISTEMP
CRUTEM
BEST
I disbelieve both parts. You're delighted that temporarily the thread has become about you and other people's anger at you. I stress temporarily. What Mark has written will stand the test of time.
And I disbelieve that you really think that others are worse than bored. We see you as a necessary evil - necessary only because the host has allowed you freedom to post since you were last banned. We don't question the host's judgment on this because there is value in a small part of your criticism, though not in my view in yourself as a pseudonymous entity designed, as Shub says, solely to make others boil. And to run off when banned to complain at the totalitarian regime at Bishop Hill - or let your eager sock puppets do that for you.
That IPCC graph is one of my favourites.
It was inserted into the final version after the 2nd round of review comments.
Clearly Jones and Trenberth knew they couldnt get it through review.
http://sites.google.com/site/globalwarmingquestions/howtheipccinventedanewcalculus
BBD
Yes. As far as Josh's cartoon is concerned - that is exactly the point he is making.
Is the rate of warming really accelerating? If so, how would one demonstrate it graphically?
You can post it on my blog - a short piece, with the graphs and everything.
BBD
When Mark T invited you to google "discrete time signal processing" and "linear systems theory" (Feb 3, 2012 at 10:51 PM), did you by any chance do so?
I did and it only served to renew my admiration for those who understand and can handle that stuff. I never had the inclination or the patience for advanced maths.
How about you? I don't think you know much about discrete time signal processing or linear systems theory either.
I am grateful that we have two experts — Mark T and Spence_UK — who are happy to come to blogs like this along with the statisticians and physicists and engineers and explain these things to the great unwashed like me (as far as that is possible).
Why pretend you know more than they do? You don't. You're forever trying to send those who disagree with you off to your pet warmist blogs, whether in the hopes they will learn or what I'm not quite sure. Why not take a leaf out of your own book and pay attention to some real experts?
Yep....figured I was right the other day about BBD (whose comments I used to read with a view to being educated. Hah!): "Infamy, Infamy, they've all got it infamy" H/T Kenneth Williams. (yawn) - but Mark T: many thanks for your input.
BBD, you may say it’s CO2 and that it’s not contentious but I’ve yet to see any real ‘scientific’ proof for either of your claims. However, I know that you tend towards post-normal science and so should not be surprised that your level of ‘proof’ is somewhat more ‘relaxed’ than mine.
The fact that the measured temperature anomalies are clearly influenced by natural factors such as volcanoes and ocean cycles is clear proof that it’s not all due to CO2, so the best you can claim is that the long-term trend is driven by CO2, to some degree. Unfortunately, even the IPCC (AR4/WG1) admit that there’s substantial uncertainty about the degree of attribution, so you’re going to have to argue your claim with them, rather than me.
As for your view not being contentious, I only have to refer to one of the Bishop’s recent posts…
http://www.bishop-hill.net/blog/2012/2/3/note-it-post.html
…to prove that there’s more than just a bit of contention at the very top.
In conclusion, the science is far from settled because: there’s more than enough ‘noise’ in the measured data to raise serious questions about the level of attribution to CO2; not one prediction based upon the CAGW hypothesis has yet been scientifically validated by real-world data, though there is some that suggests that it can be falsified.
I do not expect any sensible/direct rebuttal of my statements from you, but thought it worth writing down my ‘contrarian’ views’ so that others can consider them and make their own judgement.
BBD says:
No, it's not CO2. We can all play these games. You're pissing into the wind. And you're becoming a bore.
Famous Quotes
'I get the strong impression that you should calm down. Have a cup of tea or something.' (BBD Feb 4, 2012 at 4:20 PM)
@ Snotrocket Feb 4, 2012 at 8:32 PM
You're too kind, Snotrocket. Our resident zealot - whose dedication to the diversion of intelligent, informed discussion is almost legendary - long ago proved himself to be a tiresome (and obnoxiously rude) bore.
To my mind, his behaviours resemble those of the schoolyard bully who taunts "Hit me! Hit me! Hit me!" And when finally someone obliges, he wails, "Bwaaaaah! He hit me".
[Raise the tone please]
Well, I posted a VERY long comment explaining in detail why BBD is wrong, but the length meant it got caught in the spam trap. It has now appeared and can be found at this link.
Although I'm not sure it was worth it. If BBD doesn't understand something (happens often), he just dismisses it as snark and ignores it.
[Raise the tone please]
ALL
Do we need this food fight?
The foodfight stopped.
Spence_UK, from your Collide-a-scape link - BBD Says: January 30th, 2012 at 2:46 pm
So how much revelatory scientific insight has your 30+ comments of nonsense verse contributed to this thread. Strangely, I believe, lots. I know little of signal processing and nothing about advanced signal processing. Which quite clearly from your comments puts both of us in the same group, although only one of us is prepared to admit it. However, Mark T's contribution and particularly Spence_UK's of Feb 4, 2012 at 4:15 PM have been enlightening and extremely useful. If you had thrown the towel in earlier we all would have missed these contributions
30 deg C here in Brisbane, spot on the February average (OMG, did I say average?). Time to clean the barby and stock the fridge ready for the 50 over match, Oz vs India. How is the weather over there? I understand you're having a particularly mild winter. At least that's what the ABC told me a week ago.
Here are the five year means for HADCRUT and GISTEMP (global average T) and CRUTEM and BEST (surface T).
Does the IPCC cartoon really misrepresent the evolution of global (or surface) T over the C20th?
HADCRUT
GISTEMP
CRUTEM
BEST
I love the way it warms up after a (Little) Ice Age. Hope it lasts but that's looking questionable.
If only the Team could adjust the real temperatures instead of just their numbers..
BBD asked "Does the IPCC cartoon really misrepresent the evolution of global (or surface) T over the C20th?" Basically yes. The "acceleration" in global warming (their word from the caption) is not supported by the data. It may appear to be by looking at increasing linear trends. But now in the 21st century we have seen a steady linear trend (using a 25 year trend) or a decreasing upward trend (using shorter trends).
Using the latest data, the claim of accelerating warming can be shown to be not true. But further, It should not have been made when it was made, because the nonlinearity of the natural climate response (with AGW overlaid) does not support the linear trend analysis that they depicted.
BBD: Does the IPCC cartoon really misrepresent the evolution of global (or surface) T over the C20th?
IPCC: Note that for shorter recent periods, the slope is greater, indicating accelerated warming
How many more times do you have to be told that the the graph is not about 'representing' the 'T' over the 'C20th'? It is about making, and presenting visually, a specific claim.
Look at this graph. This is using your HADCRUT
Hasn't anyone graphed the slopes of the various surface instrumental records in the manner of calculating a moving average (moving forward a subset of a time series) for say 13 months, 10 years, 30 years and 50 years. If you did you would discover the magical appeareance of Hockey Stick type curves with the start of the blade being around 1950. Now as we all know Hockey Stick curves are immediately suspect, they invariably point to human interaction with the data.
@joshs
Hehe, you make the point far better than I did, nice!
What I find amazing is how prepared they are to shoot themselves in the foot rather than deal with things in a straightforward way. This is the sort of thing that every layman can evaluate in about 10 seconds and decide if there is a double standard at work or the players can be trusted in more complex matters.
I've responded to Shub at his blog.
Hmm, seems my predictive ability has performed well:
Pretty much on the money.
(Oh and Shub is right as well. To detect an "acceleration" you either need to detect a significant trend in the first derivative of the time series or detect a significant difference between the sample mean and zero in the second derivative, not plot cherry-picked trends on the raw data.)
Spence_UK
What I understand is the difference between obfuscation and explanation. Which is what this thread has been about.
The thread has indeed been about obfuscation and explanation. Lucid and enlightening explanations by Mark T and Spence_UK in particular and obfuscation by BBD. AKA jabberwocky.
Wait - what? Let's recap BBD's analytical contribution to this debate:
... which is both algebraically wrong and a flawed representation of what averaging really does.
I then provide a comprehensive explanation, from a statistical perspective (Mark T had already presented a signal processing perspective quite nicely, and notably both methods converge on the same answer, as they should), complete with half a dozen equations employing correct algebra, outlining detailed assumptions that go into the algebra, and why climate data fails to conform to those expectations (plus the consequences of such)
And I'm the one obfuscating? You are truly precious BBD, and I honestly don't know what we would do without you.
When I first started reading this thread, the comment that stood out was you proudly saying that 110yr trends were not "short term". But 110 yr trends ARE short term to climate. "Short term" and long term are not dictated by the amount of data we have available (e.g. if I have 10 seconds of data, that does not suddenly make 10 seconds long term!) but by the characteristics of the time series we are analysing. And as I have shown, using correct mathematics, nine millenia is pretty much still in the "short term" bracket when it comes to climate.
But surely 30 years is a long time, right? Sorry to burst anyone's bubble, but while 30 years is a long time with respect to the human lifespan, it isn't even a dot to the earth's climate system. A human lifespan, to climate, is a moment of the utmost triviality. Just to put things in perspective for you, BBD, for the next time you mistake 110 year trends as not being short term.
This was the reply I posted on my blog:
BBD
[1] Firstly, thanks for coming around to a reasonable, and correct, method of answering the question posed by the IPCC’s statement: ‘Is the global temperature rise really accelerating?’ This is more important than the results themselves
[2] Please note that the IPCC arrives at their conclusion of accelerating warming, by a method dissimilar to, and wrong, compared to our mutually acceptable one used above. This automatically falsifies their claim
[3] GISTEMP and CRUTEM are in the hands of untrustworthy fiddlers, whose actions with the temperature record, especially with the ’1940s blip’ are suspect. GISS’ methodology of extrapolation is scientifically suspect. Why are you wheeling in these cripples?
[4] In any case, even if you include them, the range for acceleration is 0-11(C/episode). This only confirms the null hypothesis in question rather than refuting it. Secondly, it simply makes the point, that a claim of accelerating warming is dependent on the data series used, rather than CO2.
[5] Questions about warming over land etc are irrelevant to the question of the method of arriving at a conclusion about acceleration of global temperature rise.
As Mike noted, the whole thing has been pointed out to BBD, and now he does accept that there is something wrong with what the IPCC did, and that if one decides to include longer contiguous periods from the past, the valid conclusion that is possible is that the rate of warming decreases. In other words, if one wishes to compare rates of warming during different times, one ought to choose non-overlapping, i.e., independent, time periods.
Since the IPCC is such a brilliant, unimpeachable, and trustworthy organization (per its own claims), with multiple checks, and despite all that, they produced such a graph, one is forced to conclude something malign about them.
If you plot the 'slope' of a moving 30 year time series (the long term change in temperature, not the average) for BEST, HadCruT and GISS you will note that BEST has a Hockey Stick shape, whilst the HadCruT and GISS show similar shaped curves pre and post AGW. The slopes for the smaller satellite data sets for the same length of time series show slightly lower changes than HadCruT and GISS.
BEST is a curious outlier. It shows much greater change in global temperatures since the 1950s than all the other instrumental records both surface and satellite. Its Hockey Stick shape indicates human interaction with the data. The BEST methodology of mixing bad data with good data based on the assumption that bad data will turn good is highly suspect, the reverse is probably true. It does however highlight what appears to be a common problem with these data sets and models - the models projections of future hotter temps only work if the instrumental data shows that the past is getting cooler and the present warmer.
The claim that the past 10 years are the warmest on record only holds for the AGW arguement if in the future this decade can be made to be cooler in the records. The need for future heating has become seriously problematic.