December 11, 2009
— Ace Iowahawk has a very ambitious idea for a post: Not only will he explain to you what the hockey stick is, and how it came to be, he will actually take you step-by-step through Mann's (et al.) process in crunching the numbers and explain to you how to produce your own temperature reconstruction graph.
This isn't a joke or parody; he's really teaching you basic statistical modeling and telling you exactly how to produce your own graph (and how Mann et al. produced theirs).
I admit, my brain doesn't want to go here: A man's got to know his limitations.
But I imagine quite a few of you have brains hooked up to handle this sort of thing, and may be pretty intrigued at the idea of running your own temperature reconstructions.
Hmmm... I guess if I am going to be hawking this issue, I really do have to try this at some point.
The thing is, it's one thing to talk about this sort of thing vague, but when you really understand something, obviously you really understand it.
It's not that forbidding. It's pretty accessible, really.
Posted by: Ace at
04:12 PM
| Comments (102)
Post contains 208 words, total size 1 kb.
Posted by: Bosk at December 11, 2009 04:16 PM (pUO5u)
Posted by: Editor at December 11, 2009 04:19 PM (YX6i/)
AGW itself isn't really that complicated, which is why all this handwaving about "scientists agree!" is so spurious.
Posted by: TallDave at December 11, 2009 04:21 PM (+3aaV)
Posted by: Editor at December 11, 2009 04:21 PM (YX6i/)
Math, again?
Posted by: huerfano at December 11, 2009 08:22 PM (BEYNH)
Yeah, seriously. I mean, math isn't really an exact science, anyway, right?
Posted by: Editor at December 11, 2009 04:23 PM (YX6i/)
Posted by: M. C. Hammer at December 11, 2009 04:24 PM (vKdhq)
I,, uh,, uh,, let me be clear, uh,, as I've said before, uh,, I,, uh,, <can I get a prompter up here?>...........
OsamaHusseinIslamObama 2012ÂÂŒ
(the terrorist-Ugihur-ACORN-media choice)
-ItÂfs never too early to campaign-
Posted by: Barry Soetoro (D-King OF The World!) at December 11, 2009 04:24 PM (UJdwQ)
Posted by: ol_dirty_/b/tard at December 11, 2009 04:28 PM (Z0bVg)
Posted by: RushBabe at December 11, 2009 04:28 PM (LKkE8)
Posted by: Christoph (D-Dip-Shit OF The World!) at December 11, 2009 04:29 PM (UJdwQ)
And it was beautiful. *throws panties on stage*
Posted by: HeatherRadish at December 11, 2009 04:31 PM (OkT2m)
Posted by: ol_dirty_/b/tard at December 11, 2009 08:28 PM (Z0bVg)
Whoa! I hope she doesn't break me. It's gonna be wild.
Posted by: Conan O'Brien at December 11, 2009 04:32 PM (YX6i/)
Posted by: Mrs. Compton at December 11, 2009 08:32 PM (NaJ/S)
Well, it depends on what the definition of numbers is.
Posted by: Billy Jeff at December 11, 2009 04:34 PM (YX6i/)
I'm bringing the cap and trade, one way or another, no matter what you bitter-clinger-racist-cracker-a$$-crackers say............ I WON REMEMBER?.....
OsamaHusseinIslamObama 2012ÂÂŒ
(the terrorist-Ugihur-ACORN-media choice)
-ItÂfs never too early to campaign-
Posted by: Barry Soetoro (D-King OF The World!) at December 11, 2009 04:34 PM (UJdwQ)
the reconstructions tend to be sensitive to the data selection
Posted by: Amused Observer at December 11, 2009 04:35 PM (Uy/AI)
Posted by: ace at December 11, 2009 04:35 PM (jlvw3)
Posted by: Editor at December 11, 2009 04:35 PM (YX6i/)
Posted by: logprof at December 11, 2009 04:36 PM (I3Udb)
Posted by: Bill D. Cat at December 11, 2009 04:36 PM (vKdhq)
I guess.
Not really. I'm lazy.
Posted by: ace at December 11, 2009 08:35 PM (jlvw3)
There's always the double post. I mean, when was the last time you double-posted yourself? Might as well get it out of the way.
Posted by: Editor at December 11, 2009 04:37 PM (YX6i/)
Yeah, seriously. I mean, math isn't really an exact science, anyway, right?
Posted by: Editor at December 11, 2009 08:23 PM (YX6i/)
Not so much as it used to be. http://tinyurl.com/y886r3d
Posted by: huerfano at December 11, 2009 04:39 PM (BEYNH)
Posted by: mghorning at December 11, 2009 04:40 PM (quoy3)
David Burge blogs at Iowahawk, considered by many to be one of the sites on the internet. His work has appeared in the Weekly Standard, Garage Magazine, Middle East Quarterly, SpeedTV.com, PajamasTV, British satire site Anorak, and Readings in American Government.
He is a veteran of several Hollywood bus tours and owns an
exclusive map to the homes of the stars. He also has amassed over $200
in Blockbuster late fees. He lives in Chicago.
Posted by: GregInSeattle at December 11, 2009 04:41 PM (B5cM9)
No time. Now, back to Bevington's "Data Analysis and Reduction for the Physical Sciences".
Light reading, as it were...
---
Additional Blond Agent
Posted by: Ace's #1 Fan at December 11, 2009 04:42 PM (SHKl9)
One problem with iowahawk's post is one of his assumptions/premises: to grant that we accept the Medieval Warming Period and the Little Ice Age. Unfortunately, there are loads of asshats that believe that those phenomena were limited to the North Atlantic region.
Posted by: logprof at December 11, 2009 08:36 PM (I3Udb)
Watts Up With That had graphs up earlier this week that show the warming periods are the exceptions, not the norms. In other words extreme cold is our planets most natural state.More like, 'Little Warm Ages'.
I'd link it, but like ace I'm lazy, but mostly because I'm half lit and its a Friday.
Posted by: Blazer at December 11, 2009 04:42 PM (+FzLa)
Who are you and what have you done with Ace?
Posted by: John Galt at December 11, 2009 04:42 PM (Ylv1H)
Posted by: OregonMuse at December 11, 2009 04:43 PM (tClfg)
Posted by: Dr. Spank at December 11, 2009 04:43 PM (mGSN1)
Posted by: Bill D. Cat at December 11, 2009 04:44 PM (vKdhq)
Actually they probably do not believe it, they just say that as part of their scam. There is simply too much countervailing evidence from ocean core samples that show the warm period and little ice age existed all over the earth.
Posted by: Vic at December 11, 2009 04:45 PM (CDUiN)
I'd link it, but like ace I'm lazy, but mostly because I'm half lit and its a Friday.
Posted by: Blazer at December 11, 2009 08:42 PM (+FzLa)
--Oh, I've seen them. I just hope my more left-loco friends on Facebook have it sink in.
Posted by: logprof at December 11, 2009 04:45 PM (I3Udb)
Posted by: nickless at December 11, 2009 04:48 PM (MMC8r)
"You think man can destroy the planet? What intoxicating vanity. Let me tell you about our planet. Earth is four-and-a-half-billion-years-old. There's been life on it for nearly that long, 3.8 billion years. Bacteria first; later the first multicellular life, then the first complex creatures in the sea, on the land. Then finally the great sweeping ages of animals, the amphibians, the dinosaurs, at last the mammals, each one enduring millions on millions of years, great dynasties of creatures rising, flourishing, dying away -- all this against a background of continuous and violent upheaval. Mountain ranges thrust up, eroded away, cometary impacts, volcano eruptions, oceans rising and falling, whole continents moving, an endless, constant, violent change, colliding, buckling to make mountains over millions of years. Earth has survived everything in its time. It will certainly survive us. If all the nuclear weapons in the world went off at once and all the plants, all the animals died and the earth was sizzling hot for a hundred thousand years, life would survive, somewhere: under the soil, frozen in Arctic ice. Sooner or later, when the planet was no longer inhospitable, life would spread again. The evolutionary process would begin again. It might take a few billion years for life to regain its present variety. Of course, it would be very different from what it is now, but the earth would survive our folly, only we would not. If the ozone layer gets thinner, ultraviolet radiation sears the earth, so what? Ultraviolet radiation is good for life. It's powerful energy. It promotes mutation, change. Many forms of life will thrive with more UV radiation. Many others will die out. Do you think this is the first time that's happened? Think about oxygen. Necessary for life now, but oxygen is actually a metabolic poison, a corrosive glass, like fluorine. When oxygen was first produced as a waste product by certain plant cells some three billion years ago, it created a crisis for all other life on earth. Those plants were polluting the environment, exhaling a lethal gas. Earth eventually had an atmosphere incompatible with life. Nevertheless, life on earth took care of itself. In the thinking of the human being a hundred years is a long time. A hundred years ago we didn't have cars, airplanes, computers or vaccines. It was a whole different world, but to the earth, a hundred years is nothing. A million years is nothing. This planet lives and breathes on a much vaster scale. We can't imagine its slow and powerful rhythms, and we haven't got the humility to try. We've been residents here for the blink of an eye. If we're gone tomorrow, the earth will not miss us."
— Michael Crichton
Posted by: Vmaximus at December 11, 2009 04:50 PM (EESSb)
Posted by: nickless at December 11, 2009 08:48 PM (MMC8r)
Rethinking Comedy: Teaching Social Justice by the Funny.
Posted by: Editor at December 11, 2009 04:50 PM (YX6i/)
Posted by: nyc redneck at December 11, 2009 04:50 PM (mItME)
Posted by: mghorning at December 11, 2009 04:51 PM (quoy3)
Posted by: CoolCzech at December 11, 2009 04:53 PM (QECjC)
Heres the article from WUWT just in case anyone else is interested. Lots of hockey stick data in this one too. In the reverse direction as far as ice core and temp data goes.
tinyurl.com/y9bpgco
Posted by: Blazer at December 11, 2009 04:53 PM (+FzLa)
Give it up you bunch of racist-bitter-clinger-cracker-a$$-crackers,, I saw the tree rings myself,, that's right,, that's right,, I was camping with Al Gore and Barney Frank when I saw 'em. My a$$ was sore the next morning,, butt I saw 'em just the same!!
OsamaHusseinIslamObama 2012ÂÂŒ
(the terrorist-Ugihur-ACORN-media choice)
-ItÂfs never too early to campaign-
Posted by: Barry Soetoro (D-King OF The World!) at December 11, 2009 04:53 PM (UvYqN)
--We're just here to give the earth plastic.
Posted by: Zombie George Carlin at December 11, 2009 04:53 PM (I3Udb)
Posted by: Blazer at December 11, 2009 08:53 PM (+FzLa)
You haven't had enough to drink, yet, Blazer.
Posted by: Editor at December 11, 2009 04:55 PM (YX6i/)
Great point! A certain radioguy pointed out this very day that lefty media cannot survive by themselves; they require subsidies in order to remain on the air... Witness air america, etc..
Posted by: TXMarko at December 11, 2009 04:55 PM (FNc7v)
Posted by: Tiger Woods at December 11, 2009 04:58 PM (quoy3)
You haven't had enough to drink, yet, Blazer.
Posted by: Editor at December 11, 2009 08:55 PM (YX6i/)
Or maybe I'm drinking too fast and overdoing it, because usually I'm not this serious.
Posted by: Blazer at December 11, 2009 05:00 PM (+FzLa)
Posted by: Tiger Woods at December 11, 2009 08:58 PM (quoy3)
But the dirty Scandis can adapt to it easy, right, Tiger?
Posted by: Editor at December 11, 2009 05:00 PM (YX6i/)
Posted by: Editor at December 11, 2009 05:01 PM (YX6i/)
Sade has a new album coming out in Feb. Schwing.
Posted by: Editor at December 11, 2009 05:04 PM (YX6i/)
Posted by: Tiger Woods at December 11, 2009 08:58 PM (quoy3)
--Dude, is it true you can get stoned, synch Ice Age with Al Gore's poetry and . . . duuuuuude!
Posted by: Stoner with melted candle on three year old newspapers and empty pizza boxes at December 11, 2009 05:06 PM (I3Udb)
Oh, Blazer is a "serious" drinker. Greeeaaaat.
Posted by: Editor at December 11, 2009 09:01 PM (YX6i/)
Shit, you know better than that. Blutarsky will be back out before the night is done, I can assure you.
Posted by: Blazer at December 11, 2009 05:08 PM (+FzLa)
...not unlike Ace's Banhammer and Son of Banhammer posts.
Has he used the Hammer??
Posted by: Indian Outlaw at December 11, 2009 05:13 PM (8zsWd)
34 Unfortunately, there are loads of asshats that believe that those phenomena were limited to the North Atlantic region.
Mann's paper showing the MWP was regional relies on evidence he says shows the Pacific was cooler during it. Woods Hole Oceanographic Institution has a new paper saying otherwise and says the Northern Hemisphere reconstructions "need to be looked at more closely"
Can't link to the paper, since this editor is a POS, but it's a peer reviewed paper, too.
Posted by: Strick at December 11, 2009 05:25 PM (93CPh)
Posted by: Popcorn at December 11, 2009 05:27 PM (OOehk)
All but one of the graphs were of Greenland ice core data. IE North Atlantic. Only the last graph was from the Vostok research station in Antarctica. As scurrilous and minor as it may be, that's how the average AGW True Believer would reply.
Posted by: Iskandar at December 11, 2009 05:33 PM (u1pln)
Posted by: ParisParamus at December 11, 2009 05:37 PM (cd0d9)
Posted by: mpur at December 11, 2009 05:41 PM (qp8iX)
"When the taste for physical gratifications among them has grown more rapidly than their education . . . the time will come when men are carried away and lose all self-restraint . . . . It is not necessary to do violence to such a people in order to strip them of the rights they enjoy; they themselves willingly loosen their hold. . . . they neglect their chief business which is to remain their own masters."
— Alexis de Tocqueville (Democracy in America, Volume 2)
Posted by: Vmaximus at December 11, 2009 05:42 PM (EESSb)
— Alexis de Tocqueville
Posted by: Vmaximus at December 11, 2009 05:48 PM (EESSb)
Trends should never be extrapolated from a regression analysis - the more involved the analysis, the more hairy the line at either end.
THAT being said, and as many times as the word 'model' was used, there is no 'model' here, just extrapolating a rather involved trend line.
Posted by: Druid at December 11, 2009 05:55 PM (Gct7d)
magic - do they have access to a computer the size of the moon that the rest of us don't know about ? If so, the folks at RHIC and many other places would love to buy some computer time, I promise. Furthermore if one takes the time to understand CO2 as a greenhouse gas one sees that, to accept the possibility of CO2 as a driver of an uncontrolled climate catastrophe, one must assume that the Earth's climate is unstable under minor temperature perturbations - which is absurd, given the Earth's long history. Of course this explains the need of the climate science high priesthood to fudge data about the Earth's history.
Posted by: rian at December 11, 2009 06:04 PM (G5p2r)
But then, I'm almost 3/4 finished with my master's in electrical engineering...
Posted by: Mrs. Peel at December 11, 2009 06:16 PM (miGLm)
Posted by: Vmaximus at December 11, 2009 06:23 PM (EESSb)
Posted by: Mark at December 11, 2009 06:38 PM (7MnBG)
Um, I know Iowahawk is actually trying to be generous to Mann, et al. That is, he is trying to be careful not to say anything that is incorrect or can be interpreted in a different way. So, I'll just go ahead & do that for him. When correllating the proxy data to the "observed" data, Iowahawk calls his step 6 "Step 6: Evaluate how well the regression model fits the observed temperature data."
In the end, the r^2 value is 0.50
This means that half the variation in observed temps matches (although Iowahawk says "can be accounted for by") the regression of the proxy data. In other words, HALF DOESN"T.
Uh, this is the "Mean" temperature of the ENTIRE GLOBE, is it not? And the best r-squared we can get from the proxy data is 0.5?!?!? There will be people who will tell you that any r^2 value can be significant, depending on this or that; but an r^2 of 1.0 is perfect correlation and 0.0 is absolutely NO correllation. Go find two things (totally unrelated) that yield an r^2 of 0.0, I dare you. Your age, or your height, or your salary, or your penis size could easily yield an r-squared of 0.50 with a limitless number of completely unrelated data. In short, despite the technical crap that some statisticians will feed you, an r-squared value of 0.50 is SHIT. Meaningless, useless. The very weakest kind of correllation. And CORRELLATION IS NOT CAUSATION, as Iowahawk seems to have forgotten.
And, as Iowahawk glosses over, the "Observed" temperatures compiled by Phil Jones are totally BOGUS, anyway. Why not do some regressions of the number of Unicorns Obama-voters have ridden in their lifetimes and see how it correllates to the Polar Bears killed by human industry - as reported by ALGORE.
The entire endeavor is psuedo-intellectual masturbation that appears to give some minimal credence to the UTTER HORSEHIT put out by Mann, Jones, Hansen, et al.
Let me just ask 2 questions:
1. Does the width of tree-rings give you an absolute ability to say what the temperature was in a given year?
2. If polar ice sometimes melts (as were being repeatedly told that it currently is), has it ever melted in the past? If it melted in the past, then for each year that the NET ice cover decreased, the so-called "annually striated glacial ice cores" that Iowahawk refers to would be MISSING TWO YEARS. So that measuring the isotope level in one striation would give you, say, the temp of the year 1776; but THE VERY NEXT striation would give you the temp of the year 1773 ... NOT 1775 (because in 1775 no ice was added, and the ice from1774 was ERASED by melting). Has anyone ever accounted for this? HOW could they? You'd have to first know the extent of the ice, as measured by the ice, to determine ..... the extent of the ice. It's all shit.
I'm unimpressed by analytics of the statistics or the code or the other manipulations used by Mann, Jones, CRU, IPCC, et al, when they completely ignore common sense issues -- like that tree ring width depends more on water than temperature, and that water and temperature are neither perfectly correllated, nor can their various effects be differentiated from each other.
YOU DON"T HAVE TO LOOK THIS DEEP. For example, for the year 1850, Phil Jones's "observed" "GLOBAL" "AVERAGE" temperature is derived from measurements (from God knows where) covering less than 16% of the planet's surface. Do you need advanced statistics to know that this cannot be done?
Posted by: Uriel at December 11, 2009 06:43 PM (+F8Li)
Posted by: Mark at December 11, 2009 07:12 PM (7MnBG)
Posted by: notropis at December 11, 2009 07:35 PM (0thcq)
I'm pretty sure the proxy data was stopped because it diverged from the rising temperatures. "Hide the decline"
Posted by: Mark at December 11, 2009 08:00 PM (7MnBG)
Anybody need a drink? (Not you, you dirty fucking scandi). I think I'll have one...
Posted by: Uriel Lost Me at December 11, 2009 08:19 PM (va0Vd)
Posted by: Lissa at December 11, 2009 09:08 PM (lrTDZ)
Posted by: ManeiNeko at December 11, 2009 09:13 PM (TiE76)
The Mann et al. 1998 paper is still "the" causation paper. After making the temperature reconstruction look like a hockeystick, he aligns, scales, and fusses with the ppm CO2 over time chart until they also have good correlation. Then claims "Tada!"
Honestly, the field said "Well, what else could it be?" at that point. There was enough hard warming in the nineties that the comments "WTH, that isn't causation" was quite muted. Additionally, everyone is focused on their own niche. The best models of 1998ish had serious issues hindcasting the warm bump of the 1930s (because they attribute too much of the blame to CO2 - which has no such hump) so they aren't any more convincing themselves. The slightly newer models have added in "estimates of aerosols" and almost kind-of manage to have a hump. And are helped by the -historical- intrumental records of the 1930s being adjusted downwards to account for Urban Heat Island effects. (Which is just too bizarre to explain in one post.)
ManeiNeko, another issue that keeps getting glossed over is the whole idea of what-in-the-hell he's actually claiming as proxies. There's a fundamentally whacked assumption about what he calls teleconnection.
If you have a tree and a co-located instrumental record, the whole idea of the rings being proxies for temperature makes some sense. And it can even be extended to "nearby." It starts to make a whole lot of sense as to why 99% of the potential proxies are just dumped outright when one realizes he's directly looking for proxies for the global average temperature.
But even that isn't completely nuts. I could buy that a tree in Colorado is simply an excellent proxy across our recorded instrumental temperature period. No foul.
But. The fundamental axiom of Climate Science is: Climate is not Weather. That is, shit changes. Wind patterns might shift slightly as weather, but a climactic shift might disrupt them completely and bury New York in ice. Er. Or something.
The very shifts they're supposed to be detecting are also exactly the same types of shifts most likely to make some other damn tree the best proxy in the world.
Posted by: Al at December 11, 2009 09:38 PM (0lyUI)
Posted by: ManeiNeko at December 11, 2009 10:40 PM (TiE76)
Posted by: Masturbatin' Pete at December 12, 2009 06:05 AM (8ysTM)
I had no idea the models were still this simplistic, the correlations so poor, the data so questionable. It must be sweet being a big name climatologist, you can predict anything you want, and with very little effort.
We did all the same cynical things back in the 70s to promote Global Cooling: scary approaching scenarios, linear models, lousy correlations, horrible data, cherry picked results, but we didn't get as many of the raving loonies out on the streets so we weren't successful. Otherwise we'd be the ones on the gravytrain, tapdancing around ten years of warming followed by the most recent ten years of cooling.
What might have been. Fame, fortune, free hookers. Sigh.
Posted by: Ambrose at December 12, 2009 07:46 AM (r5VU5)
"I've wondered for a while if the proxies even correlate very well with each other. For example, we know that tree ring width is as much related to moisture as anything. Do others? And some tree ring series, e.g., bristlecone pines, have been problematic."
The answer to this is "Hell no."
Mann's method is fundamentally weighting an average. So he's throwing 1000 proxies in to get his hockeystick. But... The weighting is quite heavy. The first batch is the bristlecones - removing that one batch causes a dramatic reduction in the hockeystickness. But the weights are heavy enough that the top 15 or so essentially count for the whole thing. That's 985 proxies dumped.
And, they're being dumped because they don't match "reality." Even though the authors of the individual papers for each proxy found something worth publishing about.
Posted by: Al at December 12, 2009 08:15 AM (0lyUI)
My principal component could use some correlating. I mean, two working spouses, a kid, two cats and a dog - private time is a thing of the past.
Anyway, one of the main take away lessons for me, is that one does not need a supercomputer to create these reconstructions and models. It's done on a desktop.
The other pre-existing lessons stand:
1. The raw temperature data, with urban heat island effects excluded, frequently show little or no warming.
2. An honest look at the proxy temperature record does not support the assertion that the current global temperature is unprecedencted.
3. Most of the last million years have been ice ages. Maybe a much larger climate forcing function is at work than man-made carbon dioxide release.
Posted by: Wm T Sherman at December 12, 2009 09:08 AM (tm15w)
Posted by: Rod Rescueman at December 12, 2009 11:10 AM (QxGmu)
Posted by: SarahW at December 12, 2009 12:25 PM (CSrvi)
Posted by: john at December 12, 2009 05:29 PM (R6S3l)
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Posted by: Dr. Spank at December 11, 2009 04:16 PM (mGSN1)