Tom Nelson spots a gem in the Climategate 2 emails:
Hockey stick co-author Ray Bradley:
“it may be that Mann et al simply don’t have the long-term trend right”;
“I hedge my bets on whether there were any periods in Medieval times that might have been “warm”, to the irritation of my co-authors!”
…
Sorry this kept you awake…but I have also found it a rather alarming graph. First, a disclaimer/explanation. The graph patches together 3 things: Mann et al NH mean annual temps + 2 sigma standard error for AD1000-1980, + instrumental data for 1981-1998 + IPCC (“do not quote, do not cite” projections for GLOBAL temperature for the next 100 years, relative to 1998. The range of shading represents several models of projected emissions scenarios as input to GCMs, but the GCM mean global temperature output (as I understand it) was then reproduced by Sarah Raper’s energy balance model, and it is those values that are plotted. Keith pointed this out to me; I need to go back & read the IPCC TAR to understand why they did that, but it makes no difference to the first order result….neither does it matter that the projection is global rather than NH….the important point is that the range of estimates far exceeds the range estimated by Mann et al in their reconstruction. Keith also said that the Hadley Center GCM runs are being archived at CRU, so it ought to be possible to get that data and simply compute the NH variability for the projected period & add that to the figure, but it will not add much real information. However, getting such data would allow us to extract (say) a summer regional series for the Arctic and to then plot it versus the Holocene melt record from Agassiz ice cap….or….well, you can see other possiblities.
[……At this point Keith Alverson throws up his hands in despair at the ignorance of non-model amateurs…]
But there are real questions to be asked of the paleo reconstruction. First, I should point out that we calibrated versus 1902-1980, then “verified” the approach using an independent data set for 1854-1901. The results were good, giving me confidence that if we had a comparable proxy data set for post-1980 (we don’t!) our proxy-based reconstruction would capture that period well. Unfortunately, the proxy network we used has not been updated, and furthermore there are many/some/ tree ring sites where there has been a “decoupling” between the long-term relationship between climate and tree growth, so that things fall apart in recent decades….this makes it very difficult to demonstrate what I just claimed. We can only call on evidence from many other proxies for “unprecedented” states in recent years (e.g. glaciers, isotopes in tropical ice etc..). But there are (at least) two other problems — Keith Briffa points out that the very strong trend in the 20th century calibration period accounts for much of the success of our calibration and makes it unlikely that we would be able be able to reconstruct such an extraordinary period as the 1990s with much success (I may be mis-quoting him somewhat, but that is the general thrust of his criticism). Indeed, in the verification period, the biggest “miss” was an apparently very warm year in the late 19th century that we did not get right at all. This makes criticisms of the “antis” difficult to respond to (they have not yet risen to this level of sophistication, but they are “on the scent”). Furthermore, it may be that Mann et al simply don’t have the long-term trend right, due to underestimation of low frequency info. in the (very few) proxies that we used. We tried to demonstrate that this was not a problem of the tree ring data we used by re-running the reconstruction with & without tree rings, and indeed the two efforts were very similar — but we could only do this back to about 1700. Whether we have the 1000 year trend right is far less certain (& one reason why I hedge my bets on whether there were any periods in Medieval times that might have been “warm”, to the irritation of my co-authors!). So, possibly if you crank up the trend over 1000 years, you find that the envelope of uncertainty is comparable with at least some of the future scenarios, which of course begs the question as to what the likely forcing was 1000 years ago. (My money is firmly on an increase in solar irradiance, based on the 10-Be data..). Another issue is whether we have estimated the totality of uncertainty in the long-term data set used — maybe the envelope is really much larger, due to inherent characteristics of the proxy data themselves….again this would cause the past and future envelopes to overlap.
…Ray [Bradley]
At 01:34 PM 7/10/00 +0200, you wrote: Salut mes amis,
I’ve lost sleep fussing about the figure coupling Mann et al. (or any alternative climate-history time series) to the IPCC scenarios. It seems to me to encapsulate the whole past-future philosophical dilemma that bugs me on and off (Ray – don’t stop reading just yet!), to provide potentially the most powerful peg to hang much of PAGES future on, at least in the eyes of funding agents, and, by the same token, to offer more hostages to fortune for the politically motivated and malicious. It also links closely to the concept of being inside or outside ‘the envelope’ – which begs all kinds of notions of definition. Given what I see as its its prime importance, I therefore feel the need to understand the whole thing better. I don’t know how to help move things forward and my ideas, if they have any effect at all, will probably do the reverse. At least I might get more sleep having unloaded them, so here goes……[Frank Oldenfield]
==============================================================
But wait, there’s more
Hockey stick co-author claims that after 1850, critical trees lost their alleged ability to record temperature
If you examine my Fig 1 closely you will see that the Campito record and Keith’s reconstruction from wood density are extraordinarily similar until 1850. After that they differ not only in the lack of long-term trend in Keith’s record, but in every other respect – the decadal-scale correlation breaks down. I tried to imply in my e-mail, but will now say it directly, that although a direct carbon dioxide effect is still the best candidate to explain this effect, it is far from proven. In any case, the relevant point is that there is no meaningful correlation with local temperature. Not all high-elevation tree-ring records from the West that might reflect temperature show this upward trend. It is only clear in the driest parts (western) of the region (the Great Basin), above about 3150 meters elevation, in trees old enough (>~800 years) to have lost most of their bark – ‘stripbark’ trees. As luck would have it, these are precisely the trees that give the chance to build temperature records for most of the Holocene. I am confident that, before AD1850, they do contain a record of decadal-scale growth season temperature variability. I am equally confident that, after that date, they are recording something else. [Malcolm Hughes]
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And he’s vain about it, to boot.
AR4’s certainty of alarming AGW from fossil fuel was manipulated from such pseudo-science.
The IPCC was the vehicle of the pseudo-science.
The ’cause’ of Mann and his fellow travelers has devolved into a wagon circling clique of pseudo-scientists.
What a great Christmas present.
Best wishes to all during this holiday season.
John
Usually even shorter than that, about 8 in most cases. The darker end wood created toward the end of the growing season is generally not counted. You are looking at June/July temperatures, mostly July.
Dizzy.
“That is old news”
The classic and meaningless rejoinder of a politician. And absolutely meaningless as a response. As is your cite to Mann. You will note that the citations in the article are the very ones discussed in this piece, with no serious attempt to analyze the variance with measured data to hypothesis. Indeed, there is no attempt to inform the reader that such a variance even exists. Instead Mann extends the proxies into entirely speculative ocean cycles, such as an extremely intense and extended La Nino cycle 1,000 years ago and says that the data aligns nicely. Babble. .
I’d read this email in the days after CG2 happened and thought this one would be made a big deal of then. Then with so many other things, I never got back to it. I am GLAD it has been brought up again!
Kudos to Tom Nelson on bringing it up again.
This is possibly deflecting the direction of this post a bit, but the parts about proxies is, I think the most significant.
It has become somewhat common for skeptics in recent years to deny their (our) denying. At least denying that they (we) deny that warming is occurring. Whenever I’d hear that, I’d wonder why. Did we really accept the graphs, even when we knew the data underlying them were corrupted? Did we accept the fundamental warming trend because we knew we were coming out of the LIA, so maybe we thought that, even if corrupted, when all was and and done we believed the trend would show up as warming anyway?
Over the last c0ouple of years, as I’ve learned more and more about the tree-ring proxies (especially), bit by bit I’ve wondered louder and louder if the correlation was valid. When I ran across a study of South Carolina cypress trees, using their tree rings as proxies for PRECIPITATION (http://www.scribd.com/doc/51676257/Buried-Cypress-Forest-in-South-Carolina) a few months ago, I kind of crossed the line. A feature cannot be a reliable proxy for BOTH precip and temps – there is simply no WAY to determine which one did how much.
It is also significant that
Then, during the CG2 hubbub Steve McIntyre had a post “Severinghaus and “Hide the Decline” (http://climateaudit.org/2011/11/28/severinghaus-and-hide-the-decline/) in which there was much discussion about tree-rings-as-proxies. That discussion had much on the “Divergence Problem” (DP), which was the underlying issue behind “hide the decline.”
Three is a lot in the CG2 emails about people discussing the DP. From beginning to end of the entire lot of emails – CG1 and CG2 both – about the DP. The DP is the time bomb in all of climate science. The entirety of climate reconstructions is built on the supposed correlation between tree-rings and temperature. Tree-rings are the keystone, the lynchpin and the little Dutch boy’s finger in the dike. Without them, there is no real window into the past.
How can I say that? A few points of data from ice cores at locales in Antarctica can’t tell us much about what is happening in the rest of the world. After all, the Arctic and Antarctic ice right now are doing their see-saw thing – when one is up the other is down. But the very few data points 1,000 or 2,000 years ago can’t tell much, not unless there is a tie-in in some other proxy or instrument data. And that tie-in is tree-rings.
But what if the tree-rings themselves aren’t correlated well? What does that do to ice cores? Based on BEST’s list of data sources, most of the proxies are tree-rings. Take them out and what happens to the reliability of the history reconstructions?
And here, in the CG2 emails, we see, time after time, the scientists are wringing their hands over the DP. And here we have Mann’s own TWO collaborators on the Hockley Stick, and both of them are saying the tree-ring proxies aren’t worth diddly.
For us skeptics, THIS is the lynchpin. This is the card that brings down the entire house of cards.
Tree-rings do NOT correlate well enough – EVER – to be used as proxies for temperature. That they seemed to for climatic short periods has led climatologists down the garden path. Most don’t know it, but they exclude most tree-ring sampling sites because there is not a strong enough signal in the tree-rings. That is why there are so many Arctic sites in the data. And now, even those and their “signals” have fallen apart – and they can’t face up to it. So they have to resort to tricks and bodges and internal conspiracies to keep the secret from getting out.
It is like a nasty family secret that must not, under any circumstances get out, or the family’s reputation will be ruined.
Well, yeah, duh…
When this supposed correlation finally blows up in their faces – and it seems increasingly that it will – climatology itself may completely fall apart. After all, without proxies, what can they possibly know about past history?
Dizzy,
You don’t seem to get it.
Several years ago Bradley publicly and strongly endorsed the hockey stick, while privately questioning it. You point out that later, in 2009, he still publicly endorsed it, ergo he must also privately endorse it. That is a non sequitor.
Another important point: At the same time Bradley was privately expressing his doubts, skeptics who publicly expressed the same doubts were being excoriated as fools or knaves.
Its a dirty business.
Mann is cited 45 times in the Ch05_paleoclimate AR5 ZOD. Plus ca change…
Political Junkie says:
December 24, 2011 at 10:42 am
Dizzy, it may not be a concern to you, but some people might wonder why the alarmists AT THE TIME were presenting a seamless “the science is settled” front while expressing severe doubts in private.
Is the current solidarity just as porous behind the scenes?>>>
To help you answer that question dizzy, here’s some thoughts about the current state of the science:
1. Tree growth is correlated in any given year to a combination of temperature, precipitation, length of growing season (which is not directly related to temperature during the growing season), CO2 levels, incidence of late frost, incidence of pestilence, competition from other trees and plants, sun spot levels, and many other factors. It is not possible to eliminate all the other factors in order to isolate temperature.
2. Tree growth occurs during the growing season, which depending on latitude may be as little as two months of the year. Tropical trees are nearly absent from tree ring studies because they are not nearly as long lived as, for example, Siberian Larch, and hence useless for long term study. As a consequence, the bulk of tree ring data comes from high latitudes with short growing seasons. There is no possible way for a tree in Siberia to in any possible way grow (and hence measure ANY of the factors regulating growth) in October, November, December, January, February, March, April and May. Even if the tree rings correlated to temperature during the growing season, they would still be useless in terms of determining annual temperatures.
3. No data from the tropics. Nearly no data from low latitude temperate zones. No data from arctic zones. The bulk of the data comes from high latitude temperate zones which have the highest natural variability on the globe. This makes the tree ring data nearly meaningless from both a statistical analysis perspective, and can in no way represent a global average temperature.
So dizzy, given that these things are well known and instantly obvious to anyone who takes even a few moments to think about them, how do you justify calling ANYTHING published about long term climate reconstructions based on this methodology “science”?
lol @ur momisugly dizzy Dizzy did you bother to apply the concept illustrated in the xkcd cartoon linked in your name? Yes, that’s science, and it works.
Dendrophrenology, OTOH, is a ludicrous posit. Trees with growing seasons of about 12 weeks and you believe we can determine global or even local temps from that? Faith is a beautiful thing when properly placed. A horrible thing when improperly placed.
http://suyts.wordpress.com/2011/11/29/dividing-by-zero/
God Bless and Merry Christmas.
Some more Christmas cheer from “Uncle Joe”….
(hey Mods…can you embed this? I promise I will use the Test page next time and figure it out…but I got Christmas stuff to do!…Andrew)
“Joe Biden talks to a 1Sky campaigner about energy policy. Biden is called out on his platform that includes coal. Both 1Sky and the Energy Action Coalition are opposed to the development of new coal fired power plants. Energy Action Coalition is running Power Vote, a national youth based campaign to get 1,000,000 youth voters voting for clean energy this election season.”
…just some more “Google Global Warming Bias”…just for fun..
Andrew
I find the notion of a long, slow, thaw to be very likely as we recovered out of the LIA. That would be more consistent with how I believe things would behave. I have a couple of papers around here somewhere on glacial advance/retreat in Alaska, too, that tend to support that notion and wood recovered from one of the glaciers shows two separate periods of advance through forest.
Ah, this is one of them:
http://web.cortland.edu/barclayd/publications/QR_2009.pdf
@davidmhoffer December 24, 2011 at 11:19 am:
This is absolutely true. How MUCH of the tree-ring “signal” – TRW or MXD, either one – is from temperature alone? No one can separate that out, saying this much is from precipitation, this much from competition with other trees, and THIS much from temperature. Not only is that impossible they KNOW it is impossible. And – in all likelihood – they know that the Divergence Problem is due to one of those – yet in the 20 or so years since the DP was recognized – they haven’t gotten any closer to understanding which other factors are causing it, nor in what measure.
As I have read it, the tropical trees aren’t giving enough of a signal – summer-vs-winter – to make it possible to distinguish one year from the next. They NEED a strong seasonal variation to make this reliably quantifiable. And the most seasonal variation is in the most-stressed regions like arctic, deserts, and high altitude. I think that is basically your point in your item 3, but thought I’d at least re-phrase it.
Exactly. Even now, with the NOAA/GISS maps, look at the extremes (some think of it as magnification or sensitivity) shown in the polar regions – how could anyone extrapolate the rest of the globe based on those regions? And then to take a few single-point data each of which represents maybe a decade or a century from those regions and then project that to represent the entire globe for, say, 1,000 years ago, it is pretty weak.
Add to all that something I read last week or so (it might or might not be in the CG2 emails), where one climatologist stated that the pre-1600 tree-ring data was so iffy that he didn’t rely on it himself.
The main issue is that these folks knew – and still know – that the data and reconstructions they are working with are really weak, but that they had – and still have – a compact among themselves to not ever let their doubts out to the public or policymakers.
I don’t think they would dare to. The money tree would dry up. And climate science would go back to the halls of academia and all the trips to exotic locales for conferences would go away, like the Cheshire Cat’s grin. And the prestige – oh, the prestige! – would be gone…
Another interesting paper is this one (paywalled but I can probably obtain a copy)
http://hol.sagepub.com/content/21/1/105.abstract
Basically it clearly shows climate variation in the Alps, particularly a very pronounced change about 4kya where climate becomes more unstable. This paper has been one of those that led me to believe that we actually started sliding into the next glacial period about 2000 year ago (after the RWP) and that process probably actually began with the major climate shift 4kya when we see the monsoon making a drastic change and a migration of the ITCZ where its seasonal range seems to be closer to the equator than it was prior to that shift. This is at the same time the Levant dries out, the Dead Sea begins a drastic decline in level, and trees that existed in that area at that time begin to die out due to drought.
Steve Garcia says:
December 24, 2011 at 11:08 am
I’d read this email in the days after CG2 happened and thought this one would be made a big deal of then. Then with so many other things, I never got back to it. I am GLAD it has been brought up again!
________
I think we are going to see them brazen it out for a while.
I’ve pointed out in the past that most all accounts point to Mann as a bully. Even Dizzy trolls on by with his “real science” paper from Mann and pals with no doubts expressed, while the email points to concern or doubt.that existed in these same people. Does Mann have the strength of personallity to keep these out of the paper?
The “decoupling” – that is simply BS. Either tree rings are a proxy for temp. or not. I think I’m going to make this my central theme for my argument – ask others to explain why trees are a temp proxy until they are not.
Merry Christmas to this accepting community of the curious.
Bob Lackey
Reading the article I had a vision of a ship’s cargo of hockey sticks sinking.
Mann’s already spun that. He said that the Sierra location that the bristlecones are from is the “sweet spot” that represents the whole world through teleconnections.
Dude’s got chutzpah.
So Bradley thinks the MWP was warm because of solar effects, based on Be10. That must have been what Jasper Kirkby thought in his article justifying CERN’s experiments regarding Svensmark’s theories on cosmic rays and clouds. Nice graphs of Be10 and C14 with temperature proxies on page 3:
http://aps.arxiv.org/PS_cache/arxiv/pdf/0804/0804.1938v1.pdf
Now, now, it is season of good will to all men and Mann. Of course he is wrong, but to be on the generous side, and let us cherry pick the start some 300 years ago, at 1700 there was a mini Hockey Stick, and since the CET correlates well with the so called ‘global temperature’, if there is such thing, then would be one in there too. Not everything is lost though, the temperatures do oscillate with the solar output at about 5-10 times the rate dr. LS tells us they should.
http://www.vukcevic.talktalk.net/miniHockeyStick.htm
I am in real trouble now.
Another glass of ‘bubbly’ please.
Happy Christmas to one and all !
Olen says:
December 24, 2011 at 12:33 pm
Reading the article I had a vision of a ship’s cargo of hockey sticks sinking.
“Boy, I got vision, and the rest of the world wears bifocals.” – Butch Cassidy
http://youtu.be/4beP5nKtruo
I still say that the mortal wound is in the neglect of oceanic and atmospheric conditions as the major driver of weather pattern variation. It is as if rhese folks don’t even know it exists.
@Bob_L December 24, 2011 at 12:11 pm
Bob, the thing is, I never thought that I would come to the point of doubting tree-rings as proxies for temperature. It seems such an entrenched idea, and I had always thought, “Well, the dendrochronologists have all this worked out, don’t they?” But bit by bit, I started wondering, slowly over the course of maybe a couple of years.
The Divergence Problem is a BIG deal. A really big deal. It is VERY important if the instruments in the last 70 years – the best documented, most precisely measured, most widely dispersed period – agree with the tree-rings. And to find out that it wasn’t just “after 1960” that the decline was happening – holy cr*p, Batman!
These guys were losing sleep over this – and not just them. Schweingruber the dendro was worried about it, too – since about 1990. Briffa co-authored papers with him about it. No one has a CLUE what is going on.
The simple explanation is that tree0rings simply aren’t proxies for temperature. But no one wants to be the one who points out the Emperor has no clothes. So they discuss that it exists, while still using the data – the data that isn’t telling them what they think it should. But they carefully mask the full impact of it.
In reading the explosive Climategate “hide the decline” email two years ago, it seemed like this was something new to them, and they were merely scrambling to maybe give them time to figure it out. But that wasn’t the context at all. The real context is that Briffa knew that this was a real problem, that had been known about for a decade or more. And Briffa stood up to Mann for a while and then caved under the Mannian onslaught. Briffa simply did not want to cut off the post-1960 data and pretend it wasn’t there. He knew it was real, even if he couldn’t explain it.
The real gist is this: If during this well-measured period the first shoe that fell was that the two don’t correlate, then the second shoe is when someone in public tells the world that tree-rings aren’t a valid proxy for temperature and all the reconstructions based on them are not reliable.
I came to this conclusion slowly and with trepidation, but after recently reading journal papers about the DP, I am now certain that this is the case. I do recommend people go to the “Severinghaus..” post on CA and read through both the comments and the links. That Bradley and Hughes – 2/3 of the MBH paper authorship – admit to themselves that the correlation is really, really not solid, that is a big thing. A huge thing.
@crosspatch:
//”Another interesting paper is this one (paywalled but I can probably obtain a copy)
http://hol.sagepub.com/content/21/1/105.abstract“//
Merry Christmas, and a gift for you:
I found the full paper. Go to http://tiny.cc/1mbr6.
“the neglect of oceanic and atmospheric conditions as the major driver of weather pattern variation”
and the effect of solar variations other than changes in TSI as a driver of changes in atmospheric conditions via the expansion and contraction of the polar air masses.
You know the easiest thing how to kill the hockey stick? Compare CET with NH CRUTEM and you will find excellent correlation. So CET represents the whole Norther hemisphere very well. Now, look at the CET backwards, notice cold cold 1680 followed by abrupt warming until 1740 and compare whether you see something similar on the hockey-stick. You will find nothing of that.
Vuk
That graph of yours, you’ve referenced it before, is there some way it can be shown so we can see the solar-temp correlation as clearly as possible? Would one of those fourier whatsits help? Analysis of cycle correlations? It looks to be of great interest. But IMHO it needs better presentation.
Could it just be simple visuals that show (a) short term correlating fluctuations (b) longer term correlating climate changes (c) the “cumulative heating effect” ie what looks like a cumulative effect of the recent series of higher-than-“normal” solar cycles?? Visually, the old GISS plots were much easier on the eye. Heck THE TEAM understand this in their graphs that nearly fooled the world about the decline hidden under some really graceful, expressive, seductive curves. Keep truth, and use their skills against them.
Now back to Christmas, also celebrating the sunlight – penetrating the darkest time of the year as well as the darkest part of people’s hearts.