NOTE: This has been running two weeks at the top of WUWT, discussion has slowed, so I’m placing it back in regular que. – Anthony
UPDATES:
Statistician William Briggs weighs in here
Eduardo Zorita weighs in here
Anonymous blogger “Deep Climate” weighs in with what he/she calls a “deeply flawed study” here
After a week of being “preoccupied” Real Climate finally breaks radio silence here. It appears to be a prelude to a dismissal with a “wave of the hand”
Supplementary Info now available: All data and code used in this paper are available at the Annals of Applied Statistics supplementary materials website:
http://www.imstat.org/aoas/supplements/default.htm
=========================================
Sticky Wicket – phrase, meaning: “A difficult situation”.
Oh, my. There is a new and important study on temperature proxy reconstructions (McShane and Wyner 2010) submitted into the Annals of Applied Statistics and is listed to be published in the next issue. According to Steve McIntyre, this is one of the “top statistical journals”. This paper is a direct and serious rebuttal to the proxy reconstructions of Mann. It seems watertight on the surface, because instead of trying to attack the proxy data quality issues, they assumed the proxy data was accurate for their purpose, then created a bayesian backcast method. Then, using the proxy data, they demonstrate it fails to reproduce the sharp 20th century uptick.
Now, there’s a new look to the familiar “hockey stick”.
Before:
After:
Not only are the results stunning, but the paper is highly readable, written in a sensible style that most laymen can absorb, even if they don’t understand some of the finer points of bayesian and loess filters, or principal components. Not only that, this paper is a confirmation of McIntyre and McKitrick’s work, with a strong nod to Wegman. I highly recommend reading this and distributing this story widely.
Here’s the submitted paper:
(PDF, 2.5 MB. Backup download available here: McShane and Wyner 2010 )
It states in its abstract:
We find that the proxies do not predict temperature significantly better than random series generated independently of temperature. Furthermore, various model specifications that perform similarly at predicting temperature produce extremely different historical backcasts. Finally, the proxies seem unable to forecast the high levels of and sharp run-up in temperature in the 1990s either in-sample or from contiguous holdout blocks, thus casting doubt on their ability to predict such phenomena if in fact they occurred several hundred years ago.
Here are some excerpts from the paper (emphasis in paragraphs mine):
This one shows that M&M hit the mark, because it is independent validation:
In other words, our model performs better when using highly autocorrelated
noise rather than proxies to ”predict” temperature. The real proxies are less predictive than our ”fake” data. While the Lasso generated reconstructions using the proxies are highly statistically significant compared to simple null models, they do not achieve statistical significance against sophisticated null models.
We are not the first to observe this effect. It was shown, in McIntyre
and McKitrick (2005a,c), that random sequences with complex local dependence
structures can predict temperatures. Their approach has been
roundly dismissed in the climate science literature:
To generate ”random” noise series, MM05c apply the full autoregressive structure of the real world proxy series. In this way, they in fact train their stochastic engine with significant (if not dominant) low frequency climate signal rather than purely non-climatic noise and its persistence. [Emphasis in original]
Ammann and Wahl (2007)
…
On the power of the proxy data to actually detect climate change:
This is disturbing: if a model cannot predict the occurrence of a sharp run-up in an out-of-sample block which is contiguous with the insample training set, then it seems highly unlikely that it has power to detect such levels or run-ups in the more distant past. It is even more discouraging when one recalls Figure 15: the model cannot capture the sharp run-up even in-sample. In sum, these results suggest that the ninety-three sequences that comprise the 1,000 year old proxy record simply lack power to detect a sharp increase in temperature. See Footnote 12
Footnote 12:
On the other hand, perhaps our model is unable to detect the high level of and sharp run-up in recent temperatures because anthropogenic factors have, for example, caused a regime change in the relation between temperatures and proxies. While this is certainly a consistent line of reasoning, it is also fraught with peril for, once one admits the possibility of regime changes in the instrumental period, it raises the question of whether such changes exist elsewhere over the past 1,000 years. Furthermore, it implies that up to half of the already short instrumental record is corrupted by anthropogenic factors, thus undermining paleoclimatology as a statistical enterprise.
…
We plot the in-sample portion of this backcast (1850-1998 AD) in Figure 15. Not surprisingly, the model tracks CRU reasonably well because it is in-sample. However, despite the fact that the backcast is both in-sample and initialized with the high true temperatures from 1999 AD and 2000 AD, it still cannot capture either the high level of or the sharp run-up in temperatures of the 1990s. It is substantially biased low. That the model cannot capture run-up even in-sample does not portend well for its ability
to capture similar levels and run-ups if they exist out-of-sample.
…
Conclusion.
Research on multi-proxy temperature reconstructions of the earth’s temperature is now entering its second decade. While the literature is large, there has been very little collaboration with universitylevel, professional statisticians (Wegman et al., 2006; Wegman, 2006). Our paper is an effort to apply some modern statistical methods to these problems. While our results agree with the climate scientists findings in some
respects, our methods of estimating model uncertainty and accuracy are in sharp disagreement.
On the one hand, we conclude unequivocally that the evidence for a ”long-handled” hockey stick (where the shaft of the hockey stick extends to the year 1000 AD) is lacking in the data. The fundamental problem is that there is a limited amount of proxy data which dates back to 1000 AD; what is available is weakly predictive of global annual temperature. Our backcasting methods, which track quite closely the methods applied most recently in Mann (2008) to the same data, are unable to catch the sharp run up in temperatures recorded in the 1990s, even in-sample.
As can be seen in Figure 15, our estimate of the run up in temperature in the 1990s has
a much smaller slope than the actual temperature series. Furthermore, the lower frame of Figure 18 clearly reveals that the proxy model is not at all able to track the high gradient segment. Consequently, the long flat handle of the hockey stick is best understood to be a feature of regression and less a reflection of our knowledge of the truth. Nevertheless, the temperatures of the last few decades have been relatively warm compared to many of the thousand year temperature curves sampled from the posterior distribution of our model.
Our main contribution is our efforts to seriously grapple with the uncertainty involved in paleoclimatological reconstructions. Regression of high dimensional time series is always a complex problem with many traps. In our case, the particular challenges include (i) a short sequence of training data, (ii) more predictors than observations, (iii) a very weak signal, and (iv) response and predictor variables which are both strongly autocorrelated.
The final point is particularly troublesome: since the data is not easily modeled by a simple autoregressive process it follows that the number of truly independent observations (i.e., the effective sample size) may be just too small for accurate reconstruction.
Climate scientists have greatly underestimated the uncertainty of proxy based reconstructions and hence have been overconfident in their models. We have shown that time dependence in the temperature series is sufficiently strong to permit complex sequences of random numbers to forecast out-of-sample reasonably well fairly frequently (see, for example, Figure 9). Furthermore, even proxy based models with approximately the same amount of reconstructive skill (Figures 11,12, and 13), produce strikingly dissimilar historical backcasts: some of these look like hockey sticks but most do not (Figure 14).
Natural climate variability is not well understood and is probably quite large. It is not clear that the proxies currently used to predict temperature are even predictive of it at the scale of several decades let alone over many centuries. Nonetheless, paleoclimatoligical reconstructions constitute only one source of evidence in the AGW debate. Our work stands entirely on the shoulders of those environmental scientists who labored untold years to assemble the vast network of natural proxies. Although we assume the reliability of their data for our purposes here, there still remains a considerable number of outstanding questions that can only be answered with a free and open inquiry and a great deal of replication.
===============================================================
Commenters on WUWT report that Tamino and Romm are deleting comments even mentioning this paper on their blog comment forum. Their refusal to even acknowledge it tells you it has squarely hit the target, and the fat lady has sung – loudly.
(h/t to WUWT reader “thechuckr”)
The paper describing the work Discover refers to is still in peer review- James Sexton is at liberty to read it when it appears. too bad he missed the more edifying news item in Science-
If Discover is all he can handle , here’s item 81 from their 2003 Top 100 Discoveries of 2002 issue
81. Rare-Jade Riddle Cracked
The Kunz Axe, a 3,000-year-old Olmec blue-jade sculpture, features a snarling creature that is part human, part jaguar.
Courtesy of The American Museum of Natural History, New York.
In 1804 naturalist Alexander von Humboldt returned to France from the Americas with jade artifacts crafted by the Olmecs. This pre-Mayan, pre-Columbian culture had left behind statues and axes made of a translucent blue-green jade found almost nowhere else in the world. Today archaeologists know the Olmecs had stopped using the stone by about 500 B.C. Later cultures favored other shades of jade, and the blue-green version became known as Olmec blue. But the geological source of the jade had never been found. Geophysicist Russell Seitz, field director of a study of Mesoamerican jade for Harvard’s Peabody Museum, had spent years looking for the elusive transparent blue-green stone. By 1999, when he took his fiancée to Guatemala for a vacation, he had given up hope of finding the mother lode. Then, by chance, he stumbled upon half a dozen shops selling small items crafted from the blue-green gem: “It had become an ornamental cottage heritage industry.” It took him nine months to track down the jade miners, who finally agreed to lead him up into the mountains. There, at an elevation of 5,700 feet, he found “a giant, economy-size jade vein.” Seitz returned several times before discovering the biggest boulders last January. Most of the jade he found is worthless. But one 300-ton monolith does contain three tons of the prized translucent blue-green mineral.
The find puts to rest one mystery but leaves many questions for archaeologists and pre-Columbian scholars, including: Why did the Olmecs stop carving jade? Perhaps their culture disappeared, or maybe the seams of jade that the Olmecs were mining, and the Olmec carvers themselves, were destroyed by volcanoes. “The deposits,” says Seitz, “have been Pompeiied several times.”
— Michael Abrams
here for comparison is the peer reviewed version:
http://research.amnh.org/users/gharlow/Jade_in_Middle_AmericaDIST2.pdf
Barry: “Best estimates give that:
The current rate of warming is unprecedented.
The current rate of CO2 rise is unprecedented”
Gawd almighty; “best estimates”; I bet. Warming unprecedented; rubbish:
http://www.woodfortrees.org/data/hadcrut3vgl/from:1976/to:1998/trend/plot/hadcrut3vgl/from:1910/to:1940/trend
Barry says:
I don’t have deeply considered answers. I have read here and there that radiation budgets for the greenhouse effect do include backscatter and reflection from atmospheric gases (eg, Ramanathan 1978), and that reflection is considered to be a very negligible factor.
Also, it doesn’t take much to consider that, even if reflection were a non-negligible influence, only half the planet is affected at any one time, while greenhouse properties are in effect all over the sphere. A key indicator to consider here is that warming has been greater for nighttime than daytime temps over the last century.
It would be interesting to pursue this, but we should do that in a more appropriate thread.
Henry says.
1)Ramanathan 1978: I was not able to open the file
2) Note that my last dimension that I want to see is per 24 hours – your observation is correct. Nevertheless, remember that the difference between the radiation measured between the top of the atmosphere and at sea level is ca. 30%. This is on a cloudless day. So, if it were not for the oxygen-ozone/ water vapor & carbondioxide, mostly, an aditional 30% radition would be slammed on top of us. This is not to be neglected….
# Don’t worry about straying a bit. God has blessed us with Wattsupwiththat. You really have to be very bad, very bad, before they throw you off here!!!
Reply: Barry is correct. We would appreciate you finding a more appropriate thread. On topic comments are preferred. ~ ctm
Henry Pool says:
August 19, 2010 at 11:46 pm
Barry says:
basic physics tells us that CO2 will cause temps to rise
Henry you are correct when you say that NO definitive study has ever been done which proves beyond doubt that CO² warms the planet and by how much.
There is a great deal of physics that defines the absorption of IR by CO² but not how that then affects the rest of the planet. Engineering quality is what we are looking for. So all you warmers, get to it.
I take it back Russell, you’re alright; have you sold the movie rights?
Re barry says: August 20, 2010 at 12:11 am
This may be confusing correlation and causation again. The HS is ‘iconic’ because it purports to prove the 1st claim. The second claim then provides causation and supports the nascent carbon trading industry.
If the current rate of warming is not unprecedented or anomalous, then the causation becomes less plausible. Hence why, 12 years after MBH98 which initially described uncertainties in climate reconstructions is stll being argued over. It is important to put current climate change into context with prior climate changes and attempt to understand *all* the factors involved.
As discussed previously, proxies and observations show many different climate cycles operating in our climate system providing the natural variability. That natural variability may well be more significant than any AGW effects and observations seem to be showing that assumed postive feedbacks for CAGW simply don’t exist.
hi folks,
i think the authors did not care about climatologie.
There are serveral errors in the paper, see zorita et al.
No use to hold it longer on the front page!
Gunnar:
Is Zorita God or are we entitled to question Zorita’s opinion??
So why should anybody take any note of an opinion of Zorita et al.?
What arguments do Zorita et al. provide?
Are those arguments worthy of consideration and – if so – why?
Richard
Stephen Richards says:
“Henry you are correct when you say that NO definitive study has ever been done which proves beyond doubt that CO² warms the planet and by how much”.
that’s my point exactly. I have been saying this as well. WE NEED TO GET A BALANCE SHEET. Of all the gases in the atmosphere. By how much they cool and by how much they warm up. In W/m3(%CHG relevant range)/m2/24hours
I was mocking you all here earlier by giving a simple reason for the MWP:
In those days, 1000 years ago, earth was overpopulated by animals and they produced a lot of methane. Apparently methane is a strong GHG. (how strong?)
So it became warmer. Then man came and killed the animals. And then it became ice cold..
Obviously, without any test results from actual experiments, the above statement is just as untrue as to claim that CO2 causes modern warming.
But if anyone claims that CO2 is warming the planet , he must prove this to me and to the rest of the world. I am waiting for you.
http://letterdash.com/HenryP/more-carbon-dioxide-is-ok-ok
Gunnar says:
“There are serveral errors in the paper, see zorita et al.”
As far as I can tell, Zorita made two main observations. Firstly, M&W made references to so called Mann techniques which Mann never actually used in his paper, and seem to have little understanding of what Mann et al had actually done. Secondly, they took Mann’s data and applied correct statistical techniques which led to the conclusion that the proxy data was of no use as a temperature proxy.
The first point led Zorita to claim that “We have seen climate scientists write papers without the help of statisticians, and now we are seeing the reverse”. The second point however, is enough on its own to dismiss the proxy data. And in the end, isn’t that all that really matters?
Common guys, go for the thousand comments!
*putting more popcorn in microwave*
ping!
The various studies use different methodologies. You’ve retreated from PCA calibration to some ambiguous ‘skewing’.
Richard, you’re grasping at straws. The chief M&M criticism is about the PC analysis used in MBH 1998. The other papers don’t use that methodology.
If you can reference the common methodology from the body of each of the papers I just listed (the links are there to make it easy for you) then I’ll pay attention. Otherwise, it’s seems clear to me you’re talking out of your hat.
Gunnar says:
August 20, 2010 at 5:20 am
hi folks,
i think the authors did not care about climatologie.
There are serveral errors in the paper, see zorita et al.
No use to hold it longer on the front page!
This stupidity has been answered on every blog in the blogosphere and here. They did not do science. Zorito is a clown throwing straws at the paper. These are STATISTICIANS, they did statistics. Get It!? They used the team’s data NOT their methods. They did not need a paleo, they did not need Zorito et al. Now read it carefully and you will see their conclusions and don’t forget to read the scales on the XY axes.
Atomic Hairdryer
You are confused. MBH 1999 says nothing about the comparative rates of warming. Rather they say the resolution is not robust enough to say more than they do, which is about the relative temperature levels.
No one ever used the MBH 1999 paper (or the controversial HS graph) to talk about rates of warming.
Other papers do attempt to assess the rate of warming, and the results are generally as I said.
cohenite,
I am referring to the 20th century temperature rise, not 30-year blocks within it (which have some similarities – but then we need to talk about attribution – not here, though)
re: Gunnar says:
August 20, 2010 at 5:20 am
Dr. Zorita has a Phd in solid state physics, he switched to “paleoclimatology” because that is were the funding is.
He is as much a “climatologist” as McShane, he has just worked in the branch and knows about the “research”.
I suspect, though, that his statistics skills are better than Mann’s.
Climatology IS NOT a branch of science, it is simply a common interest in showing everybody that CO2 is bad.
We don’t need “climatology”.
Hal
Bwana Watts:
Thanks for the dictionary link defining ‘moran’ urbanely as someone you disagree with.
I stand corrected- all those tall Kenyan fellows who insist _they_ are moran only get away with it because their spear rattling deters disagreement.
Come to think of it, Marc really is kind of like that .
Jambo.
REPLY: Do you treat all members of the public with such a condescending attitude? And academics wonder why the public does not take them seriously when they try to communicate AGW ideas. You are exhibiting the same sort of attitude as Phil Jones and the team. – Anthony
stephen richrds,
Firstly, there is no such thing as a definitive paper. Were Einstein’s relativity papers ‘definitive?’
Lab tests performed thousands of times in high schools and universities definitively show that increasing CO2 in a volume of atmosphere will result in more infrared absorption leading to the heating of the volume.
That is the empirical basis of greenhouse theory. That part isn’t controversial. The mechanism is substantiated.
For the atmosphere, we have line calculations of the absoprtive properties CO2 and the other gases, observed increase of CO2 in the atmosphere (35% greater than its pre-industrial levels)c, orroboration by observed blocking of upwelling infrared radiation over time (by satellites), observed cooling of the stratosphere, the temperature record and attribution studies (to name a few).
The empirical (successfully tested and observed each time) fact of greenhouse warming in the lab leads to the theory that this will play out in the atmosphere. Hundreds of thousands of observations of various components bear this out.
No one has been able to video a particle of smoke causing disease in human beings. but we accept that smoking increases the risk of disease because of thousands of correlative studies. We can’t video the progress of photons through the atmosphere either, but we can observe the darkening radiance over time in the bands strongly absorbed by CO2 using satellites, we can shoot radiation through a chamber of air being filled with CO2 and clearly observe the effects. AGW is a combination of empirical tests, observations and calculations, same as most other theories we bet our lives on.
Tens of thousands of studies examine this, too. It would be nice to have a nearby planet composed much like ours is and dump enormous quantities of CO2 into its atmosphere to test the results. Instead, we’ve found ourselves running the experiment with the planet we live on, before we were even aware we were doing it.
@richard S
The introduction already contains a terrible and unnecessary paragraph, full of errors:
For example, Antarctic ice cores contain ancient bubbles of air which can be dated quite accurately. The temperature of that air can be approximated by measuring the ratio of ions and isotopes of oxygen and hydrogen.
Well, past temperatures are reconstructed from the isotope ratio of water molecules in the ice, and not from air in the air bubbles. The air bubbles themselves cannot be dated accurately, since air can flow freely in the upper 50 or meters of firn, and the bubbles are only sealed when ice is finally formed
http://klimazwiebel.blogspot.com/2010/08/mcshane-and-wyner-on-climate.html
and so on
Wijnand says:
August 20, 2010 at 7:29 am
“Common guys, go for the thousand comments!
*putting more popcorn in microwave*
ping!”
lol, I’ll try, but this is getting tedious!
Deep climate did finally respond to me.
“I’ll answer a couple of your points.
1. “The fact that 2 separate time block preformed well and all other didn’t doesn’t validate anything.”
The point is those *same* blocks did not perform well in M&W. In fact, the proxies performed worse there than most of the interpolated blocks. At most, this suggests that first/last block is a “harder” validation test to pass. As well, it was misleading of M&W to imply that good early and late block performance was somehow related to the choice of first and last block, conveniently omitting that the effect was for interpolated blocks only, *not* the first and last blocks actually used by paleoclimatologists.
But in any event it’s clear their validation methodology does not apply to real paleoclimatology studies (Lasso overfitting/suboptimal screening, shorter validation window etc.)
2. Collaboration
Of course there are many statisticians working with climate scientists. Off the top of my head – Doug Nychka, PeterBloomfield, Richard Smith … This is the best way for statisticians to contribute – when statisticians try to do it on their own, the result is inevitably flawed.
3. Further, you state they rely on gray literature
I clearly stated that it was the background section that did so. Why should that be permissable?”
The response in point one is an obvious point of contention. M&W seemed to say the climatologists were doing it wrong. I’m not in a position to make a judgment on whether they are correct or not. We’ll have to wait and learn before we can come to an informed judgment. But, I know that one doesn’t use the various statistical methodologies to fit the theory, but rather to validate the theory. Their point 2 is funny and related to point 1. The statement “when statisticians try to do it on their own, the result is inevitably flawed.” seems to be saying they don’t like the conclusions, so they must be flawed. It further implied that temp numbers (and their proxies) are special kind of number in which statisticians aren’t capable of processing alone. It is a laughable argument. Point 3 is even funnier. The critique of M&W at deep climate dedicated a large part of the critique to point out the paper mentioned “grey material” in their background statements. For some reason, Deep Climate doesn’t think this should be permissible. The fact that M&W didn’t use any of the gray material in the study itself is apparently lost on them. The gray material didn’t alter or change the study in any manner and was used only in side comments. And only once in the conclusions, so the paper’s statement “While the literature is large, there has been very little collaboration with university level, professional statisticians.” (citing Wegman) Seems to be cause to invalidate the paper!
As mentioned before, this is getting rather tedious, so I’ll try to close with a thought. This study is a study to determine if temp proxies are reliable or not. It is easy to get moving to tangents from there. Having followed this discussion from just about start to finish, I find the only relevant criticism of the paper being whether they used the proper methodologies or not. Obviously, the people that prefer to believe climate alarmism contend they didn’t. But usually, when making this argument the reasoning is because they didn’t get the answers the alamists prefer.(and visa versa) I have yet to see here or anywhere else anything cited as to why M&W’s paper is incorrectly applying statistical methods other than opinion. No accepted papers, no math or statistical laws or axioms or corollaries, ect. Neither has anyone found and error in the calculations. Just, “I don’t agree, so they did it wrong.” The paper itself goes into great detail as to why they choose their methods and why other methods are problematic. Further, they even went as far as to use other methods to see if the conclusions would change.(local vs. global) Apparently, the results were the same. The paper is an easy read even if the maths are difficult. It is a refreshingly straight forward paper that one doesn’t loose themselves in nuanced jargon as so many seem to do, lately. I greatly look forward to the back and forth the statisticians (and hopefully climatologists) will have discussing the paper after it is published. Guys and gals, temps and their proxies are are represented by numbers. They aren’t magical numbers in which only certified climatologists can interpret or process. It is long past due that the general public understands this and we remove the mystical veil of climatology. We can only get to truth when we understand we are all the guardians of truth and not a select few.
This has been a hoot! Anthony, congrats on the length of this thread. Set any records?
Barry says
“Lab tests performed thousands of times in high schools and universities definitively show that increasing CO2 in a volume of atmosphere will result in more infrared absorption leading to the heating of the volume”.
Henry says:
1) The experiments were performed incorrectly.
2) the correlation is the other way around: heat causes more CO2 in the air.
e.g.
http://letterdash.com/HenryP/more-carbon-dioxide-is-ok-ok
3)by how much
The current AGW theory is a bit like this: let us have a planet, let us increase the CO2 a bit, let us see if the temp. goes up, it id, so that must be it.
So I say:
http://wattsupwiththat.com/2010/08/17/breaking-new-paper-makes-a-hockey-sticky-wicket-of-mann-et-al-99/#comment-462042
@gunnar
OK – you didn’t like the introduction to the new paper. That is your privilege.
But exactly which bit of the substance of the paper i.e. the statistical bit, do you object to?
It is dumb to reject a present just because you don’t like the colour of the wrapping paper. If you have no other objections, I will take it that you agree with their substantive conclusions??
Stephan says:
August 20, 2010 at 2:53 am
“No one has noticed but this must have been Google’s smartest ever way of avoiding this getting out there. Type “hockey stick climate”and you will get one link dealing with this. They have gotten around it by making the authors names + paper title prominent but of course the general population would never use this to find info about hockey stick…..”
I don’t know if anyone has responded to that, but I wonder why it is that I find a substantially larger number of entries in the search-return list by google (more than 300,000).
Still, using bing.com for the same search produces an ostensible 4.3 million entries in the search return list for the same keywords.
I found that to be true for other comparisons of search results, especially if they fall into the “politically incorrect” category. A good reason for not using google.com for searches.
RR Kampen:
Thankyou for your responses to my comments that you post at August 20, 2010 at 1:07 am.
You dispute two of my statements but your disputes are mistaken.
I wrote concerning the AGW hypothesis:
“The hypothesis predicts most warming of the air relative to the surface at altitude in the tropics.”
But you reply:
“In reality the hypothesis predicts most warming at high latitudes, particularly northern high latitudes. The hypothesis does so now and it did so when I studied climatology in an era the IPCC still had to be set up. The observations are conform hypothesis.”
Sorry, but the IPCC AR4 agrees with me and not you.
The matter is explained in Chapter 9 of the AR4 and you can read it at
http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter9.pdf
Figure 9.1 (on page 675) summarises the expected responses to various forcings from 1880 to 1999. Figure 9.1(c) shows the expectation from GHG increase and Figure 9.1(f) the sum of all forcings.
Figure 9.1(c) is the only diagram of the set of individual forcings that provides the pattern of warming I described.
And both Figures 9.1 (c) and (f) display the pattern I described because the AGW prediction is that the effect of the increased GHGs is to overwhelm the effects of the other forcings.
That warming at altitude in the tropics has not happened according to radiosonde (i.e. balloon) measurements taken over the last 50 years and has not happened according to MSU (i.e. satelire) measurements taken since 1979.
Indeed, the data indicates slight cooling at altitude in the tropics (i.e. the opposite of the expected effect of GHGs).
And I said:
“That’s 40 years of cooling and 28 years of warming. Global temperature is now similar to that of 1990.”
But you have replied saying:
”Reality: the past decade was warmest; decade 1990′s second warmest, decade 1980′s third warmest and the difference between the nineties and tens is bigger than between the eighties and nineties. In other words: warming is accelerating.
Also, we are almost on par with 1998, not 1990 – without a superNiño and during deep solar minimum: http://www.weerwoord.be/uploads/14820101561.png . Some ice is melting, too.”
Sorry, but even Phil Jones agrees that there has been no statistically significant warming for the last 15 years (i.e. since 1995). And the period from 1940 to 1970 showed similar decline.
Furthermore, if there has been no warming since 1995, within the error estimates then I am correct to say that “Global temperature is now similar to that of 1990”.
So, my statements are correct according to the HadCRUT3 data set.
And your assertion that “warming is accelerating” is plain fantasy. Indeed, warming stopped from its rapid rate from ~1970 to ~2000 some 10 years ago. A rational discussion would be as to if and when similar rapid warming will resume.
You conclude by asserting:
“AGW cannot be debunked because it is the reality.”
A truthful statement is that
AGW has been debunked by reality.
Richard
Henry,
Oh, nonsense. You were present at thousands of lab tests? You ever done one?
Both are true.
CO2 absorbing radiance in a volume of atmosphere is bog standard science. There are a variety of examples on youtube even. This one is the clearest I know of.
Did you actually read the paper this post is about?