Continuing my walk down memory lane in honor of the Paris Climate Conference, (well and also for my pal AL with his hate-on for Dr. Mann and rejection of climate proxy data in general as described in the comments thread at Prof Ivar Giaever's pathetic YouTube PseudoScience talk), I'm going to reprint a few posts I'd originally written for my Citizenschallenge Blog a couple years back since the information they hold is a valid and relevant today as it was then.
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Traveling around the blogosphere these past years I keep running into the same misinformation being repeated based on the "authority" of an economist and a mining prospector turned mining engineer with a mathematical background and a political bone to pick.
Basically they are dead set against any sort of limitations or restrictions being put on carbon fuels and the global warming greenhouse gases we are adding to our thin atmosphere. Unfortunately they are so politically motivated that they have tossed scientific standards out the window and have adopted the ruthless standards of power-politics where any dirty trick and misrepresentation is part of the 'rules of engagement.'
Unfortunately, this global warming situation requires a commitment to listening and learning or Catastrophic Global Warming will become a self-fulfilling prophecy.
In order to shed light on the many mistakes and misrepresentations Ross McKitrick and Stephen McIntyre are guilty of I have culled the search results over at RealClimate.org to produce this voluminous reference list.
It is in chronological order - I hope a one stop source for this information may come in handy for some in their struggle to educate our business and political leaders along with all the folks who prefer to ignore this situation that touches everyone of us. I've included links within the title to the original at RealClimate.org so please do check them out!
I appreciate the folks at RealClimate.org allowing me to continue with this effort.
Step right up and see real science in action.
Jul 23, 2003 Rutherford et al - RealClimate
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Nov 22, 2004 RealClimate: Rutherford et al 2005 highlights
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Dec 4, 2004 RealClimate: False Claims by McIntyre and McKitrick regarding the Mann et al.(1998) reconstruction
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Feb 14, 2005 RealClimate: A disclaimer
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Jul 13, 2005 Mann - RealClimate {Letter to US Rep Whitfield and US Rep Barton}
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Oct 24, 2005 RealClimate: Hockey sticks: Round 27
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Apr 4, 2006 RealClimate: Heat Rising at the Washington Post
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Apr 19, 2006 RealClimate: Kristof on the Apocalypse
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Jul 19, 2006 RealClimate: The missing piece at the Wegman hearing
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Dec 12, 2007 RealClimate: Tropical tropospheric trends
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Jul 12, 2008 RealClimate: Aerosols, Chemistry and Climate
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Feb 8, 2009 RealClimate: On replication
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Sep 30, 2009 RealClimate: Hey Ya! (mal)
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Jan 8, 2010 RealClimate: Lindzen and Choi Unraveled
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Apr 7, 2010 RealClimate: Climate scientist bashing
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Jul 22, 2010 RealClimate: The Montford Delusion
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Feb 22, 2011 RealClimate: E&E threatens a libel suit
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Mar 9, 2011 RealClimate: Wahl-to-Wahl coverage
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May 11, 2012 RealClimate: Yamalian yawns
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I use a simple ellipsis to signify omissions of a few words or lines,
an ellipsis within brackets signifies substantial sections of worthwhile reading that have been omitted.
Any personal comments are within {} brackets.
Jul 23, 2003 ... Proxy-Based Northern Hemisphere Surface Temperature Reconstructions: Sensitivity to Method, Predictor Network, Target Season, and Target Domain
from the ABSTRACT
Results are presented from a set of experiments designed to investigate factors that may influence proxy-based reconstructions of large-scale temperature patterns in past centuries.
The factors investigated include
1) the method used to assimilate proxy data into a climate reconstruction,
2) the proxy data network used,
3) the target season, and
4) the spatial domain of the reconstruction.
Estimates of hemispheric-mean temperature are formed through spatial averaging of reconstructed temperature patterns that are based on either the local calibration of proxy and instrumental data or a more elaborate multivariate climate field reconstruction approach.
The experiments compare results based on the global multiproxy dataset used by Mann and coworkers, with results obtained using the extratropical Northern Hemisphere (NH) maximum latewood tree-ring density set used by Briffa and coworkers. Mean temperature reconstructions are compared for the full NH (Tropics and extratropics, land and ocean) and extratropical continents only, with varying target seasons (cold-season half year, warm-season half year, and annual mean).
The comparisons demonstrate dependence of reconstructions on seasonal, spatial, and methodological considerations, emphasizing the primary importance of the target region and seasonal window of the reconstruction. The comparisons support the generally robust nature of several previously published estimates of NH mean temperature changes in past centuries and suggest that further improvements in reconstructive skill are most likely to arise from an emphasis on the quality, rather than quantity, of available proxy data.
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Nov 22, 2004 ... The claims of McIntyre and McKitrick regarding the Mann et al (1998) temperature reconstruction have recently been discredited by the following peer-reviewed article to appear in the American Meteorological Society journal, “Journal of Climate“:
Rutherford, S., Mann, M.E., Osborn, T.J., Bradley, R.S., Briffa, K.R., Hughes, M.K., Jones, P.D., Proxy-based Northern Hemisphere Surface Temperature Reconstructions: Sensitivity to Methodology, Predictor Network, Target Season and Target Domain, Journal of Climate, in press (2005).
1. page 13, 2nd paragraph (through top of page 14):
It should be noted that some falsely reported putative errors in the Mann et al.(1998) proxy data claimed by McIntyre and McKitrick (2003) are an artifact of
(a) the use by these latter authors of an incorrect version of the Mann et al. (1998) proxy indicator dataset, and
(b) their misunderstanding of the methodology used by Mann et al. (1998) to calculate PC series of proxy networks over progressively longer time intervals.
In the Mann et al. (1998) implementation, the PCs are computed over different time steps so that the maximum amount of data can be used in the reconstruction.
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3. page 33, beginning 2nd paragraph (key passages highlighted for emphasis):
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The close reproducibility of the MBH98 reconstruction based on both (a) the use of an independent CFR method and (b) the use of the individual proxies used by MBH98 rather than the Multiproxy/PC representation used by MBH98, discredits the arguments put forth by McIntyre and McKitrick (2003) in support of their putative correction to the MBH98 reconstruction. ...
Dec 4, 2004 ... A number of spurious criticisms regarding the Mann et al (1998) proxy-based temperature reconstruction have been made by two individuals McIntyre and McKitrick ( McIntyre works in the mining industry, while McKitrick is an economist). These criticisms are contained in two manuscripts (McIntyre and McKitrick 2003 and 2004–the latter manuscript was rejected by Nature; both are collectively henceforth referred to as “MM”).
MM claim that the main features of the Mann et al (1998–henceforth MBH98) reconstruction, including the “hockey stick” shape of the reconstruction, are artifacts of a) the centering convention used by MBH98 in their Principal Components Analysis (PCA) of the North American International Tree Ring Data Bank (‘ITRDB’) data, b) the use of 4 infilled missing annual values (AD 1400-1403) in one tree-ring series (the ‘St. Anne’ Northern Treeline series), and c) the infilling of missing values in some proxy data between 1972 and 1980.
Each of these claims are demonstrated to be false below. ...
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[McIntyre and McKitrick have additionally been discredited in a recent peer-reviewed article by Rutherford et al (2004)].
[Added 1/6/05: See also "On Yet Another False Claim by McIntyre and McKitrick" which discredits the claimed "Monte Carlo" experiment results from the rejected McIntyre and McKitrick comment to Nature] ...
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Dec 4, 2004 ... Numerous myths regarding the so-called "hockey stick" reconstruction of past temperatures, can be found on various non-peer reviewed websites, internet newsgroups and other non-scientific venues. The most widespread of these myths are debunked below:
MYTH #0: Evidence for modern human influence on climate rests entirely upon the "Hockey Stick" Reconstruction of Northern Hemisphere mean temperatures indicating anomalous late 20th century warmth. ...
MYTH #1: The "Hockey Stick" Reconstruction is based solely on two publications by climate scientist Michael Mann and colleagues (Mann et al, 1998;1999). ...
MYTH #2: Regional proxy evidence of warm or anomalous (wet or dry) conditions in past centuries contradicts the conclusion that late 20th century hemispheric mean warmth is anomalous in a long-term (multi-century to millennial) context. ...
MYTH #3: The "Hockey Stick" studies claim that the 20th century on the whole is the warmest period of the past 1000 years. ...
MYTH #4: Errors in the "Hockey Stick" undermine the conclusion that late 20th century hemispheric warmth is anomalous. ...
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{click the American flag for the English version}
Dec 4, 2004 ... Instrumental data describing large-scale surface temperature changes are only available for roughly the past 150 years. Estimates of surface temperature changes further back in time must therefore make use of the few long available instrumental records or historical documents and natural archives or ‘climate proxy’ indicators, such as tree rings, corals, ice cores and lake sediments, and historical documents to reconstruct patterns of past surface temperature change. Due to the paucity of data in the Southern Hemisphere, recent studies have emphasized the reconstruction of Northern Hemisphere (NH) mean, rather than global mean temperatures over roughly the past 1000 years.
The term “Hockey Stick” was coined by the former head of NOAA’s Geophysical Fluid Dynamics Laboratory, Jerry Mahlman, to describe the pattern common to numerous proxy and model-based estimates of Northern Hemisphere mean temperature changes over the past millennium. This pattern includes a long-term cooling trend from the so-called “Medieval Warm Period” (broadly speaking, the 10th-mid 14th centuries) through the “Little Ice Age” (broadly speaking, the mid 15th-19th centuries), followed by a rapid warming during the 20th century that culminates in anomalous late 20th century warmth (Figure 1). Numerous myths regarding the “hockey stick” can be found on various non-peer reviewed websites and other non-scientific venues. ...
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The simulations all show that it is not possible to explain the anomalous late 20th century warmth without including the contribution from anthropogenic forcing factors, and, in particular, modern greenhouse gas concentration increases. A healthy, vigorous debate can be found in the legitimate peer-reviewed climate research literature with regard to the precise details of empirically and model-based estimates of climate changes in past centuries, and it remains a challenge to reduce the substantial uncertainties that currently exist. Despite current uncertainties, it nonetheless remains a widespread view among paleoclimate researchers that late 20th century hemispheric-scale warmth is anomalous in a long-term (at least millennial) context, and that anthropogenic factors likely play an important role in explaining the anomalous recent warmth.
Reviews of past scientific research in this area can be found in the following peer-reviewed journal articles:
- Jones, P.D., Mann, M.E., Climate Over Past Millennia, Reviews of Geophysics, 42, RG2002, doi: 10.1029/2003RG000143, 2004.
- Mann, M.E., Ammann, C.M., Bradley, R.S., Briffa, K.R., Crowley, T.J., Hughes, M.K., Jones, P.D., Oppenheimer, M., Osborn, T.J., Overpeck, J.T., Rutherford, S., Trenberth, K.E., Wigley, T.M.L., On Past Temperatures and Anomalous Late 20th Century Warmth ,Eos, 84, 256-258, 2003.
- Jones, P.D., T.J. Osborn, and K.R. Briffa, The evolution of climate over the last millennium, Science, 292, 662-667, 2001.
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Dec 8, 2004 ... RealClimate: In a recent paper, McKitrick and Michaels (2004, or “MM04″) argue that non-climatic factors such as economic activity may contaminate climate station data, and thus, may render invalid any estimates of surface temperature trends derived from these data. They propose that surface temperature trends may be linked to various local economic factors, such as national coal consumption, income per capita, GPD growth rate, literacy rates, and whether or not temperature stations were located within the former Soviet Union. If their conclusions were correct, this would hold implications for the reliability of the modern surface temperature record, an important piece of evidence indicating 20th century surface warming. However, numerous flaws with their analysis, some of them absolutely fundamental, render their conclusions invalid.
First of all, there are a number of issues that they did not address that logically must must be addressed for their conclusions to be tenable. MM04 failed to acknowledge other independent data supporting the instrumental thermometer-based land surface temperature observations, such as satellite-derived temperature trend estimates over land areas in the Northern Hemisphere (Intergovernmental Intergovernmental Panel on Climate Change, Third Assessment Report, Chapter 2, Box 2.1, p. 106) that cannot conceivably be subject to the non-climatic sources of bias considered by them.
Furthermore, they fail to reconcile their hypothesis with the established large-scale warming evident from global sea surface temperature data that, again, cannot be influenced by the local, non-climatic factors they argue contaminate evidence for surface warming. By focusing on thermometer-based land observations only, and ignoring other evidence conflicting with their hypothesis, MM04 failed to address basic flaws in their arguments.
Perhaps even more troubling, it has been noted elsewhere that MM04 confused “degrees” and “radians” in their calculations of areal weighting factors, rendering all of their calculations incorrect, and their conclusions presumably entirely invalid.
The focus of this piece, however, is on yet another fundamental problem with their analysis as identified by Benestad (2004). Benestad (2004) repeated their analysis using a different statistical model (linear and generalised multiple regression model) and the same data set. Benestad (2004) first reproduced the basic results of MM04 (i.e., established similar coefficients for the various factors used by MM04) using the full data set. This established an appropriate baseline for further tests of the robustness of their statistical model. As described below, their statistical model failed these tests, dramatically.
For one thing, the statistical significance they cited for their results was vastly overstated. ...
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Jan 6, 2005 ... McIntyre and McKitrick (MM), in one of their many false claims regarding the Mann et al (MBH98) temperature reconstruction, assert that the “Hockey Stick” shape of the reconstruction is an artifact of the “non-centered” Principal Components Analysis (PCA) convention used by MBH98 in representing the North American International Tree Ring Data Bank (ITRDB) data series.
(a) that the hockey stick pattern emerges using either the MM (centered) or MBH98 (non-centered) PCA conventions, but was censored by MM through an inappropriate application of selection rules for determining the number of Principal Component (PC) to retain,
(b) that use of the correct number of PC series (5) to be kept with the MM (centered) convention retains the characteristic “Hockey Stick” pattern as an important predictor, and yields essentially the same temperature reconstruction as MBH98, and finally
(c) the MBH98 reconstruction is recovered even if PCA is not used at all to represent the North American ITRDB Data (i.e., each individual tree-ring series is used as a predictor with equal weight in the analysis). The claim by MM that the hockey stick pattern arises as an artifact of the PCA centering convention used by MBH98 is seen to be false on multiple levels.
Here, however, we choose to focus on some curious additional related assertions made by MM holding that
(1) use of non-centered PCA (as by MBH98) is somehow not statistically valid, and
(2) that “Hockey Stick” patterns arise naturally from application of non-centered PCA to purely random “red noise”.
Both claims, which are of course false, were made in a comment on MBH98 by MM that was rejected by Nature , and subsequently parroted by astronomer Richard Muller in a non peer-reviewed setting–see e.g. this nice discussion by science journalist David Appell of Muller’s uncritical repetition of these false claims.
These claims were discredited in the response provided by Mann and coworkers to the Nature editor and reviewers, which presumably formed the primary basis for the rejection of the MM comment.
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Jan 27, 2005 ... The “hockey stick” reconstruction of temperatures of the past millennium has attracted much attention – partly as it was high-lighted in the 2001 IPCC report as one of the important new results since the previous IPCC report of 1995, and partly as it has become the focus of a number of challenges. Discussion about the “hockey stick” is conducted with considerable fervor in the public media, where this curve is often presented as if it were a proof, or even the most important proof, of anthropogenic influence on climate.
As someone who has not worked on the past millennium, I do not want to discuss the merits of the often rather technical challenges (which have been dealt with elsewhere on this site). Rather, I want to discuss the “what if…” question: what if really some serious flaw was discovered in the “hockey stick” curve? What would that mean?
So let’s assume for argument’s sake that Mann, Bradley and Hughes made some terrible mistake in their statistical analysis, so we need to discard their results altogether. This wouldn’t change our picture of the last millennium (or anything else) very much: independent groups, with different analysis methods, have arrived at similar results for the last millennium.
The details differ (mostly within the uncertainty bounds given by Mann et al, so the difference is not significant), but all published reconstructions share the same basic features: they show relatively warm medieval times, a cooling by a few tenths of a degree Celsius after that, and a rapid warming since the 19th Century. Even without Mann et al, we’d still be stuck with a “hockey stick” type of curve – quite boring.
So let’s try some more exciting “what ifs”. ...
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Jan 29, 2005 ... by Gavin Schmidt and Stefan Rahmstorf
Two stories this week, a paper in Nature (Stainforth et al, 2005) describing preliminary results of the climateprediction.net experiments, and the Meeting the Climate Challenge report from a high level political group have lead to dramatic headlines. On the Nature paper, BBC online reported that “temperatures around the world could rise by as much as 11ºC “; on the latter report it headlined: “Climate crisis near ‘in 10 years’”. Does this mean there is new evidence that climate change is more serious than previously thought? We think not.
Both issues touch on the issue of uncertainty, in particular, the uncertainty in the global climate sensitivity.
It is important to know roughly what the climate sensitivity of the planet is. There are a number of ways to do this, using either climate models or data or a combination of both. From the earliest experiments model estimates have ranged from around 2 to 5°C (for 2xCO2). ...
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Jan 20, 2005 ... by Michael Mann and Gavin Schmidt
On this site we emphasize conclusions that are supported by “peer-reviewed” climate research.
That is, research that has been published by one or more scientists in a scholarly scientific journal after review by one or more experts in the scientists’ same field (‘peers’) for accuracy and validity.
What is so important about “Peer Review”? As Chris Mooney has lucidly put it:
~~ [Peer Review] is an undisputed cornerstone of modern science. Central to the competitive clash of ideas that moves knowledge forward, peer review enjoys so much renown in the scientific community that studies lacking its imprimatur meet with automatic skepticism. Academic reputations hinge on an ability to get work through peer review and into leading journals; university presses employ peer review to decide which books they’re willing to publish; and federal agencies like the National Institutes of Health use peer review to weigh the merits of applications for federal research grants. ~~
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Next, we discuss the first of three so-called “bombshell” papers that supposedly “knock the stuffing out of” the findings of the IPCC.
Patrick Michaels and associates billed his own paper (McKitrick and Michaels, 2004) (co-authored by Ross McKitrick ), this way:
~~After four years of one of the most rigorous peer reviews ever, Canadian Ross McKitrick and another of us (Michaels) published a paper searching for “economic” signals in the temperature record. …The research showed that somewhere around one-half of the warming in the U.N. surface record was explained by economic factors, which can be changes in land use, quality of instrumentation, or upkeep of records. ~~
It strikes us as odd, to say the least, that, after one of the “most rigorous peer reviews ever”, nobody involved (neither editor, nor reviewers, nor authors) seems to have caught the egregious basic error that the authors mistakenly used degrees rather than the required radians in calculating the cosine functions used to spatially weight their estimates**. This mistake rendered every calculation in the paper incorrect, and the conclusions invalid — to our knowledge, however, the paper has not yet been retracted.
Remarkably, there were still other independent and equally fundamental errors in the paper that would have rendered it entirely invalid anyway. To the journals credit, they published a criticism of the paper by Benestad (2004) to this effect. It may come as no surprise that McKitrick and Michaels (2004) was published in Climate Research and was handled by none other than Chris de Frietas.
The other two “bombshell” papers were published in the AGU journal Geophysical Research Letters. ...
Another relevant GRL paper was the article by Legates and Davis (1997) which criticized the use of “centered correlations” common to numerous “Detection and Attribution” studies supporting the detection of human influence on recent climate change. ...
Next, we consider the paper by Soon et al (2004) published in GRL which criticized the way temperature data series had been smoothed in the IPCC report and elsewhere. True to form, contrarians immediately sold the results as ‘invalidating’ the conclusions of the IPCC, with the lead author Willie Soon himself writing an opinion piece to this effect.
Once again, a few short months later, a followup article was published by one of us (Mann, 2004) that invalidated the Soon et al (2004) conclusions, demonstrating (with links to supporting Matlab source codes and data) how (a) the authors had, in an undisclosed manner, inappropriately compared trends calculated over differing time intervals and (b) had not used standard, objective statistical criteria to determine how data series should be treated near the beginning and end of the data.
It is unfortunate that a followup paper even had to be published, as the flaws in the original study were so severe as to have rendered the study of essentially no scientific value.
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... However, as demonstrated above, even when it initially breaks down, the process of peer-review does usually work in the end. But sometimes it can take a while. Observers would thus be well advised to be extremely skeptical of any claims in the media or elsewhere of some new “bombshell” or “revolution” that has not yet been fully vetted by the scientific community.
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Jan 27, 2005 ... by Michael Mann and Gavin Schmidt
In a previous post, we discussed a number of examples where the “Peer Review” process has failed, and poor papers have been published in the ostensibly peer-reviewed literature. In this context, we revisit our previous discussions of the flawed work of McIntyre and McKitrick (henceforth “MM”).
MM published a paper, in the controversial journal Energy and Environment, claiming to “correct” the proxy-based reconstruction of Northern Hemisphere temperatures published by Mann et al (1998–henceforth “MBH98″).
Following the all-too-familiar pattern, this deeply flawed paper was heavily promoted by special interests as somehow challenging the scientific consensus that humans are altering the climate (an excellent account is provided by science journalist Dan Vergano of USA Today here).
As detailed already on the pages of RealClimate, this so-called ‘correction’ was nothing more than a botched application of the MBH98 procedure, where the authors (MM) removed 80% of the proxy data actually used by MBH98 during the 15th century period (failing in the process to produce a reconstruction that passes standard “verification” procedures–an error that is oddly similar to that noted by Benestad (2004) with regard to another recent McKitrick paper). Indeed, the bizarre resulting claim by MM of anomalous 15th century warmth (which falls within the heart of the “Little Ice Age”) is at odds with not only the MBH98 reconstruction, but, in fact the roughly dozen other estimates now published that agree with MBH98 within estimated uncertainties.
All of their original claims have now been fully discredited (see e.g. this previous post as well as this discussion of a paper ‘in press’ in the Journal of Climate by Rutherford et al). MM however, continue to promote false and specious claims. ...
Their second criticism is of the statistic employed by MBH98 as diagnostic of statistical skill, the “Reduction of Error” or “RE” (note that this statistic was favored as a skill diagnostic in prominent recent studies by Cook et al (2004) and Luterbacher et al (2004) in Science). This criticism was summarily dismissed by the reviewers of the rejected MM Nature comment. MM instead promote the use of a simple linear correlation coefficient (“r“) in its place. ...
On a more general note, the intense criticism leveled against MBH98 is peculiar in that the authors of that study have in fact emphasized and quantified the uncertainties in their reconstructions in published work, something that was very difficult in previously published methodologies.
The follow-up to MBH98 by Mann et al (1999) was entitled “Northern Hemisphere Temperatures During the Past Millennium: Inferences, Uncertainties, and Limitations” (italics added for emphasis), and indeed emphasized the substantial remaining uncertainties in proxy-based estimates of Northern Hemisphere temperature change in past centuries.
The validity of the so-called “Hockey Stick” can, of course, neither rest on the strength of MBH98, nor any one reconstruction or model simulation result alone. Rather, as demonstrated in IPCC(2001) [see this comparison here] and numerous additional studies since, it is what is perhaps more aptly termed the “Hockey Team”–that is, the multiple independent reconstructions and model simulations that now indicate essentially the same pattern of hemispheric mean temperature variation in past centuries, that support a “Hockey Stick” description of past temperature changes.
Ironically, while some continue to attack this nearly decade-old work, the actual scientific community has moved well beyond the earlier studies, ...
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Feb 14, 2005 ... Readers of the Feb. 14th, 2005 Wall Street Journal may have gotten the impression that RealClimate is in some way affiliated with an environmental organisation. We wish to stress that although our domain is being hosted by Environmental Media Services, and our initial press release was organised for us by Fenton Communications, neither organization was in any way involved in the initial planning for RealClimate, and have never had any editorial or other control over content.
Neither Fenton nor EMS has ever paid any contributor to RealClimate.org any money for any purpose at any time. Neither do they pay us expenses, buy our lunch or contract us to do research. All of these facts have always been made clear to everyone who asked (see for instance: http://www.sciencemag.org/content/vol306/issue5705/netwatch.shtml).
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Feb 18, 2005 ... by Gavin Schmidt and Caspar Amman
Due to popular demand, we have put together a ‘dummies guide’ which tries to describe what the actual issues are in the latest controversy, in language even our parents might understand.
This guide is in two parts, the first deals with the background to the technical issues raised by McIntyre and McKitrick (2005) (MM05), while the second part discusses the application of this to the original Mann, Bradley and Hughes (1998) (MBH98) reconstruction. The wider climate science context is discussed here, and the relationship to other recent reconstructions (the ‘Hockey Team’) can be seen here. ...
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May 11, 2005 ... To our readers who have followed the supposed ‘hockey stick controversy’, this press release from NCAR just out today, will be of interest.
"Ammann and Wahl’s findings contradict an assertion by McIntyre and McKitrick that 15th century global temperatures rival those of the late 20th century and therefore make the hockey stick-shaped graph inaccurate. They also dispute McIntyre and McKitrick’s alleged identification of a fundamental flaw that would significantly bias the MBH climate reconstruction toward a hockey stick shape. Ammann and Wahl conclude that the highly publicized criticisms of the MBH graph are unfounded."
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Jun 22, 2005 ... We are disappointed that the Wall Street Journal (WSJ) has chosen to yet again distort the science behind human-caused climate change and global warming in their recent editorial “Kyoto By Degrees” (6/21/05) (subscription required).
Last week, the U.S. National Academy of Sciences and 10 other leading world bodies expressed the consensus view that “there is now strong evidence that significant global warming is occurring” and that “It is likely that most of the warming in recent decades can be attributed to human activities”. And just last week, USA Today editorialized that “not only is the science in, it is also overwhelming”.
It is puzzling then that the WSJ editors could claim that “the scientific case….looks weaker all the time”. ...
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Mann - RealClimate {Letter to Rep Whitfield and Rep Barton}
Professor Raymond S. Bradley Letter to Congressman Barton and Congressman Whitfield
Jul 13, 2005
Rep. J. Barton, Chairman
House Committee on Energy and Commerce Rep. Ed Whitfield, Chairman
Subcommittee on Oversight and Investigations 2125 Rayburn House Office Building Washington, D.C. 20515
House Committee on Energy and Commerce Rep. Ed Whitfield, Chairman
Subcommittee on Oversight and Investigations 2125 Rayburn House Office Building Washington, D.C. 20515
Dear Congressman Barton and Congressman Whitfield,
{...} You are quite mistaken in thinking that this conclusion rests largely on the work of Bradley, Hughes or Mann, or on the three of us together. The IPCC Report (Climate Change 2001: The Scientific Basis”, published by Cambridge University Press) is 881 pages in length. It weighs 5.5 pounds and contains over 200 figures and 80 Tables. It would be absurd to think that the weight of its conclusions rests on any one figure or Table; rather it paints a convincing picture in the totality of its science, as noted succinctly in its title.
You mention that there have been several papers published that disagree with the conclusions of papers published by Mann, Bradley and Hughes. This should come as no surprise. That is the nature of scientific activity. We publish a paper, and others may point out why its conclusions or methods might be wrong. We publish the results of additional studies that may argue with those critics, and provide data that might support or modify our original conclusions. That’s normal. Scientific developments generally take place incrementally, one or two steps forward, perhaps one or two back...or perhaps a little to the side. But as time goes on, robust results generally become accepted as other studies come to similar conclusions using perhaps different data, different approaches, different starting points. That is where we now stand with respect to our conclusion that the recent warming is unprecedented within the context of (at least) the last 1000 years. {...}
My responses to your specific questions are as follows:
- My curriculum vitae is enclosed. It lists over 140 papers and 11 books that I have
written, co-authored or edited over the past ~30 years. Where appropriate, the source of funding for the research underlying the various papers can be found in the Acknowledgements section of each paper. - A list of grants received for my research can be found in my curriculum vitae.
- I have been a P.I. on awards made to the University of Massachusetts. I refer you
to the Director of the Office of Grants and Contract Administration at the University for details of “agreements, adjustments, exceptions” etc, of which they have records. - Some of the data used in my research is archived at the World Data Center for Paleoclimatology (WDC-A), Boulder, Colorado. Other data are also available to the general public at NOAA or in other national data depositories around the world. When I, or my students, have generated data sets they are generally sent to the WDC-A once the results have been published. This is the normal procedure followed in my field. If somebody is interested in specific data or procedures used, they generally write to me requesting that information. Data related to the Mann et al. (1998) paper are available at:
ftp://holocene.evsc.virginia.edu/pub/MBH98
5. I get somewhere between 30,000 and 35,000 emails a year. These include many inquiries about my research ranging from schoolchildren doing projects, to college students and scientists carrying out their own research, to religious fundamentalists who wish to convince me that the end is nigh. I do not have time to respond to all requests but try to respond to as many inquiries as I can.
6. McIntyre and McKitrick have criticized our work, claiming to have “audited” and “corrected” what we did. In fact, they did neither. Had their article been subjected to an appropriate scientific review, it is unlikely that it would have been published. They then submitted their criticisms to Nature; we responded to these through extensive correspondence with Nature.
After reviewing their claims, Nature chose not to publish them.
They then submitted essentially the same criticisms to Geophysical Research Letters. The editors of this journal made an error by not requesting comments on the article from us (as Nature did). This is the normal procedure when the work of any author is directly criticized; then (if recommended by reviewers) both the criticism and the response are jointly published for all to judge who is right; this procedure was not followed. If it had been, once again I believe the criticisms of McIntyre and McKitrick would probably not have been published.
There is a very good guide to the issues involved at this web site: http://www.realclimate.org/index.php?p=121
This shows why their criticisms are erroneous and irrelevant to our basic conclusion that the recent warming is unprecedented in the context of the last 1000 years.
7. I had a very minor role in the last IPCC assessment, limited to reading draft sections of Chapter 2 and providing comments. ...
Raymond S. Bradley
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
Aug 31, 2005 ... The untold story of how a front-page article and powerful U.S. politicians morphed former mining executive Stephen McIntyre into a scientific superstar.
Why do so many U.S business leaders and members of Congress doubt the scientific consensus on global warming? Consider the case of Stephen McIntyre, a
semiretired businessman. His attack on one climate-change study, known as the “hockey stick”— a study often cited to make the case for global warming — plucked McIntyre from obscurity and got him featured on the front page of the February 14, 2005, Wall Street Journal.
semiretired businessman. His attack on one climate-change study, known as the “hockey stick”— a study often cited to make the case for global warming — plucked McIntyre from obscurity and got him featured on the front page of the February 14, 2005, Wall Street Journal.
The page-one story caught the attention of Rep. Joe Barton (R-TX), chair of the House Committee on Energy and Commerce. By late June, Barton was creating his own headlines by demanding that prominent researchers turn over the raw data from the hockey-stick analysis.
When ES&T contacted more than a dozen leading scientists to find out how these events affected the scientific consensus on climate change, many researchers began criticizing the Wall Street Journal and Barton. ...
{...}
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
Oct 24, 2005 ... Two more teams in the seemingly endless jousting over the ‘hockey-stick’ have just made their entry onto the field. In the first two (of four) comments on the original McIntyre and McKitrick (2005) (MM05) paper in GRL, von Storch and Zorita, and Huybers have presented two distinct critiques of the work of M&M.
The two comments focus on the ‘PC normalisation’ issue raised in MM05 which we discussed previously. Specifically, von Storch and Zorita show that in a GCM model emulation of the Mann, Bradley and Hughes (MBH) method, changing the PC normalisation technique makes no difference to the eventual reconstruction (i.e. it is not the normalisation that creates the ‘hockeystick’), consistent with earlier conclusions.
Huybers comments that neither of the two suggested normalisations are actually optimal, and proposes a third method which looks like it gives results halfway between MBH and MM05.
However, given the von Storch result, this too is unlikely to matter in the final reconstruction.
Huybers additionally makes an interesting point regarding the calculation of significance levels in MM05 and shows that a crucial step (the rescaling of variance of the proxies to match the variance in the instrumental calibration period) was missed out. Including it produces results identical to MBH.
For each comment comes a reply, and in the M&M responses, they introduce a number of further complications and focus on the quality of some of the proxies that were input data into the MBH methodology. We note as an aside that this is quite a different criticism than claiming that MBH’s methodology contains ‘coding errors’ (to quote one of the Ms). Indeed, the quality of paleo-climatic data and its relationship to climate variables has been discussed all along (see for instance MBH99).
~ ~ ~ ~ ~ ~ ~ 2006 ~ ~ ~ ~ ~ ~ ~
Apr 4, 2006 ... The Washington Post has published a second op-ed in as many days about global warming (“Spinning Global Warming”, By Robert D. Novak, Page A19, April 03, 2006–story is no longer available on the website, but the Chicago Sun Times version is available here). In this one, Novak claims that Hansen in 1988 over-predicted global warming by 400% (a story originated by Pat Michaels and subsequently propagated by Michael Crichton). This story is a fabrication that has already been set right by us in 2004.
Smearing Hansen, a leading climate scientist and member of the National Academy of Sciences, appears to have become sport among contrarian commentators (see our earlier discussions here and here). As ad hominem attacks and “shoot the messenger” strategies are often the last refuge for those losing the substantive debate, this might be viewed by some as a positive sign, indicative of just how intellectually bankrupt the contrarian movement has become.
We are Earth scientists. We are not part of a vast conspiracy to perpetrate a hoax, nor are we crowd-following herd animals. We are concerned about the world we are leaving to our children. We have not asked James Hansen, but we would venture a guess that his motives are similar. As scientists we have a duty to speak out when our findings strongly suggest that a dangerous and harmful development is underway – just like someone who sees smoke billowing out of a house has a duty to call the fire brigade. ...
We are Earth scientists. We are not part of a vast conspiracy to perpetrate a hoax, nor are we crowd-following herd animals. We are concerned about the world we are leaving to our children. We have not asked James Hansen, but we would venture a guess that his motives are similar. As scientists we have a duty to speak out when our findings strongly suggest that a dangerous and harmful development is underway – just like someone who sees smoke billowing out of a house has a duty to call the fire brigade. ...
{...}
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
Apr 19, 2006 ... We have noted with pleasure Nicholas Kristof’s column, The Big Burp Theory of the Apocalypse (TimesSelect subscription required), which appeared in the New York Times of 18 April. This column is built around the possibility of a catastrophic methane release from marine clathrate decomposition, but at heart it is really a lament that the more conventional and better understood harms of global warming have not proved sufficient to get the attention of the White House or Congress. ...
{...}
Perhaps closest to our hearts is Kristof’s cogently stated theme that uncertainty is in the nature of the science, and is no excuse for inaction — indeed should be a spur to greater action. “The White House has used scientific uncertainty as an excuse for its paralysis.
But our leaders are supposed to devise policies to protect us even from threats that are difficult to assess precisely — and climate change should be considered even more menacing than a nuclear-armed Iran.” He concludes, “The best reason for action on global warming remains the basic imperative to safeguard our planet in the face of uncertainty, and our leaders are failing wretchedly in that responsibility.”
Kristof is a 2006 winner of the Pulitzer Prize for commentary. Congratulations, Nick! We hope you keep on reading RealClimate.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
Jul 19, 2006 ... {...}
Wegman had been tasked solely to evaluate whether the McIntyre and McKitrick (2005) (MM05) criticism of Mann, Bradley and Hughes (1998) (MBH) had statistical merit. That is, was their narrow point on the impacts of centering on the first principal component (PC) correct? He was pointedly not asked whether it made any difference to the final MBH reconstruction and so he did not attempt to evaluate that.
Since no one has ever disputed MM05′s arithmetic (only their inferences), he along with everyone else found that, yes, centering conventions make a difference to the first PC.
This was acknowledged way back when and so should not come as a surprise. From this, Wegman concluded that more statisticians should be consulted in paleo-climate work. Actually, on this point most people would agree – both fields benefit from examining the different kinds of problems that arise in climate data than in standard statistical problems and coming up with novel solutions, and like most good ideas it has already been thought of.
For instance, NCAR has run a program on statistical climatology for years and the head of that program (Doug Nychka) was directly consulted for the Wahl and Ammann (2006) paper.
But, and this is where the missing piece comes in, no-one (with sole and impressive exception of Hans von Storch during the Q&A) went on to mention what the effect of the PC centering changes would have had on the final reconstruction – that is, after all the N. American PCs had been put in with the other data and used to make the hemispheric mean temperature estimate.
Because, let’s face it, it was the final reconstruction that got everyone’s attention.Von Storch got it absolutely right – it would make no practical difference at all.
This is what MBH would have looked like using centered PC analysis: ...
Red is the original MBH emulation and green is the calculation using centered PC analysis (and additionally removing one of the less well replicated tree ring series). (Calculations are from Wahl and Amman (2006), after their fig. 5d). Pretty much the same variability and the same ‘hockey stick’. We’d be very surprised if anyone thought that this would have made any difference to either the conclusions or the subsequent use of the MBH results.
In fact, it’s even more simple, Throw out that PC analysis step completely, what do you get?
Again, red is the original MBH98 multiproxy+PC analysis, green is if the raw data are used directly (with no PC analysis at all). (This comes from Rutherford et al (2005) and uses a different methodology – RegEM – to calibrate paleoclimate proxy data against the modern instrumental record, but that doesn’t make any difference for this point).
Why doesn’t it make any difference? It’s because the PC analysis was used to encapsulate all of the statistically relevant information in the N. American tree ring network and so whatever patterns are in there they will always influence the final reconstruction.
So what would have happened to the MBH results if Wegman and his colleagues had been consulted on PC centering conventions at the time? Absolutely nothing.
Can we all get on with something more interesting now?
~ ~ ~ ~ ~ ~ ~ 2007 ~ ~ ~ ~ ~ ~ ~
Feb 3, 2007 ... New addition: Download an annotated pdf of the Fraser report. An interactive pdf file, to be read on the screen, is here, and a printable version is here. Suggestions for further commenting are welcome. Additions to the pdf have to be short, and tied to particular pieces of text or figures. And of course we will only incorporate comments that we deem to be scientifically sound and cogent.
*****************
While most of the world’s climate scientists were following the IPCC fest last week, a few contrarians left out in the cold were trying to to organize their own party.
An unofficial, “Independent Summary for Policymakers” (ISPM) of the IPCC Fourth Assessment report has been delivered by the Fraser Institute. It’s a long, imposing-looking document, resembling, come to think of it, the formatting of the real Summary for Policymakers (SPM) document that was released on Friday after final negotiations of the IPCC in Paris last week.
The Fraser Institute has assembled an awesome team of 10 authors, including such RC favorites as tilter-against-windmills-and-hockey-sticks Ross McKitrick, and other luminaries such as William Kininmonth, MSc, M.Admin — whose most recent paper is “Don’t be Gored into Going Along” in the Oct-Nov issue of Power Engineer. To be fair, he did publish a paper on weather forecasting, back in 1973. ...
Why go to all the trouble of producing an “independent” summary? The authors illuminate us with this wisdom regarding the official Summary for Policymakers: “A further problem is that the Summary for Policy Makers attached to the IPCC Report is produced, not by the scientific writers and reviewers, but by a process of negotiation among unnamed bureaucratic delegates from sponsoring governments.” This statement (charitably) shows that the Fraser Institute authors are profoundly ignorant of the IPCC process.
In fact, the actual authors of the official SPM are virtually all scientists, and are publicly acknowledged. Moreover, the lead authors of the individual chapters are represented in the writing process leading to the SPM, and their job is to defend the basic science in their chapters. ...
{...}
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Dec 9, 2007 ... Recently, I received multiple requests to discuss a paper, due to appear in Journal of Geophysical Research (JGR-atmosphere), that has been presented in the media just before the Bali conference and the Nobel Peace prize ceremony here in Oslo, Norway. The paper concludes that the warming measured over land is most likely exaggerated due to non-climatic effects, and it presents a regression analysis suggesting that the real (climatic) global mean temperature trend should be ~50% lower over land.
So, are the surface temperature trends inflated? This new paper by McKitrick & Michaels (henceforth ‘M&M2007‘) is a followup of an earlier paper they wrote in 2004 in Climate Research (MM2004a), which I discussed in my first RC post (Are Temperature Trends Affected by Economic Activity?) and in a commentary in Climate Research (Benestad, 2004). ...
One of my main concerns then was that their analysis had not taken into consideration the dependency between the data points, as the temperature exhibits non-negligible spatial correlations. Furthermore, data from the same country were compared with the same national value in terms of economic indices. It was a bit like doing a poll by asking 10 people the same question 100 times and then claiming that it’s a survey with a sample size of 1000. ...
{...}
The fact that they used sea-level pressure (SLP) data from (1974) because they could not find more recent data, suggest that they still are not up-to-date. Updated data, such as the National Center for Environmental Prediction SLP, have long been available from NOAA Climate Diagnostics Center. Furthermore, a wealth of up-to-date climate data are available from the KNMI (Dutch Meteorological Institute) ClimateExplorer.
Their regression analysis appears to suffer from over-fitting, since they have thrown in a lot of variables (both ‘meteorological’ and ‘economical’) for various vague reasons.
Not surprisingly, their analysis produces some strange results as a result of this shortcoming. ...
{...}
I also think that M&M2007 is biased and gives an incorrect picture, as they do not discuss the fact that also the world oceans are warming up, and whether any economic activity can take the blame for that. I think it is difficult to argue that factors such as the urban heat island effect plays an important role here.
They do not mention my criticisms raised in Benestad (2004) either, which discussed a number serious concerns about their previous study; They merely state, as if it were a matter of fact, that urbanisation and economic activity has been shown to affect local and regional temperature measurements – citing their old criticised paper. ...
{...}
I find it a bit ironic when people use satellite data measurements to argue that GHG is unimportant. They rely on the fact that these measurements are derived using the very same type of physical laws as those predicting an enhanced greenhouse effect due to increased GHG levels (neglecting feedback processes). ...
So in summary, I think the results of M&M2007 analysis and conclusions are invalid because
- They do not properly account for dependencies.
- They over-fit the regression.
- Their results look unreasonable.
- They “cherry pick” the MSU data that gives the lowest trend
- They do not properly account for dependencies.
- They over-fit the regression.
- Their results look unreasonable.
- They “cherry pick” the MSU data that gives the lowest trend
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
Dec 12, 2007 ... Some old-timers will remember a series of ‘bombshell’ papers back in 2004 which were going to “knock the stuffing out” of the consensus position on climate change science (see here for example). Needless to say, nothing of the sort happened.
The issue in two of those papers was whether satellite and radiosonde data were globally consistent with model simulations over the same time. Those papers claimed that they weren’t, but they did so based on a great deal of over-confidence in observational data accuracy (see here or here for how that turned out) and an insufficient appreciation of the statistics of trends over short time periods.
Well, the same authors (Douglass, Pearson and Singer, now joined by Christy) are back with a new (but necessarily more constrained) claim, but with the same over-confidence in observational accuracy and a similar lack of appreciation of short term statistics.
{...}
equilibrium run with 2xCO2
equilibrium run with a 2% increase in solar forcing
The first thing to note about the two pictures is how similar they are. They both have the same enhancement in the tropics and similar amplification in the Arctic. They differ most clearly in the stratosphere (the part above 100mb) where CO2 causes cooling while solar causes warming. It’s important to note however, that these are long-term equilibrium results and therefore don’t tell you anything about the signal-to-noise ratio for any particular time period or with any particular forcings.
If the pictures are very similar despite the different forcings that implies that the pattern really has nothing to do with greenhouse gas changes, but is a more fundamental response to warming (however caused). Indeed, there is a clear physical reason why this is the case – the increase in water vapour as surface air temperature rises causes a change in the moist-adiabatic lapse rate (the decrease of temperature with height) such that the surface to mid-tropospheric gradient decreases with increasing temperature (i.e. it warms faster aloft). This is something seen in many observations and over many timescales, and is not something unique to climate models.
{...}
~ ~ ~ ~ ~ ~ ~ 2008 ~ ~ ~ ~ ~ ~ ~
Jul 12, 2008 Everyone can probably agree that the climate system is complex. Not only do the vagaries of weather patterns and ocean currents make it hard to see climate changes, but the variability in what are often termed the Earth System components complicates the picture enormously. ...
{...}
The hook for this piece of foolishness were two interesting articles published this week by Ruckstuhl and colleagues and a draft EPA report on the impacts of climate on air quality. First, Ruckstuhl et al found that as aerosols have decreased in Europe over the last few decades (as a result of environmental standards legislation), the amount of solar radiation at the ground has increased while the amount reflected to space has decreased. They hypothesize that this may have helped Europe warm faster in the last few decades than it would have otherwise done. ...
... This is just an update to the ‘global brightening‘ story we have touched on before. ...
But the NewsBusters article succeeded in getting almost every aspect of these stories wrong. How do I correct thee? Let me count the ways.
- Aerosols are not smog: First they confuse aerosols with photochemical smog. ...
- Europe is not the Globe: ...
- Surface ozone is not in the stratosphere: Next, NewsBusters asserts that the ozone story is confusing because of the:
".. treaty called the Montreal Protocol. This was designed to reduce and eventually eliminate the production and release of a number of substances thought at the time to be depleting ozone."
Ummm…. those substances (chiefly chlorofluorocarbons – CFCs) are still thought to be depleting the ozone layer – which is in the stratosphere, some 30km above the ground-level ozone that people shouldn’t be breathing. CFCs have no impact on ground-level ozone at all (since their reactive chlorine is only released in the stratosphere). - The final inanity:
"Wouldn’t it be fascinating if such efforts [such as the Montreal Protocol] lead to cleaner air around the world which ended up warming the planet, and that additional warmth is now breaking down the very ozone we thought we could save?"
Every part of this sentence is wrong. The Montreal Protocol had no impact on cleaning the air, it stopped the growth of CFCs which are powerful greenhouse gases (in addition to their role in depleting stratospheric ozone), therefore it slowed global warming, rather than increasing it, and we aren’t trying to save ground-level ozone.
http://www.realclimate.org/index.php/archives/2008/07/aerosols-chemistry-and-climate/comment-page-4/
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
Sep 3, 2008 ... What makes science different from politics?
That’s not the start of a joke, but it is a good jumping off point for a discussion of the latest publication on paleo-reconstructions of the last couple of millennia. As has been relatively widely reported, Mike Mann and colleagues (including Ray Bradley and Malcolm Hughes) have a new paper out in PNAS with an update of their previous work. And this is where the question posed above comes in: the difference is that with time scientists can actually make progress on problems, they don’t just get stuck in an endless back and forth of the same talking points.
We discussed what would be required in an update of these millennial reconstructions a few months back and the main principles remain true now. You need proxies that are a) well-dated, b) have some fidelity to a climate variable of interest, c) have been calibrated to those variable(s), d) that are then composited together somehow, and e) that the composite has been validated against the instrumental record.
The number of well-dated proxies used in the latest paper is significantly greater than what was available a decade ago: 1209 back to 1800; 460 back to 1600; 59 back to 1000 AD; 36 back to 500 AD and 19 back to 1 BC (all data and code is available here). This is compared with 400 or so in MBH99, of which only 14 went back to 1000 AD. The increase in data availability is a pretty remarkable testament to the increased attention that the paleo-community has started to pay to the recent past – in part, no doubt, because of the higher profile this kind of reconstruction has achieved. The individual data-gatherers involved should be applauded by all. ...
{...}
So what does it all mean? First off, this paper (like MBH98 before it) is not an attribution study. That means that the reasons for any of the ups-and-downs in the records are not demonstrated by these papers alone. Attribution of the recent trends (as discussed in IPCC AR4) to anthropogenic effects has mostly focussed on the last 150 years and did not use any paleo-data.
Nonetheless, there have been a couple of key studies that have used this kind of data along with simple energy balance models (Crowley, 2000; Hegerl et al, 2006 for instance) and it will be interesting to see if this new reconstruction will make any difference to their conclusions.
Secondly, in comparison with previous reconstructions, the current analysis does not provide many surprises. Medieval times are warmer than the Little Ice Age as before, and a little warmer using the EIV method than was the case in MBH99. ...
{...}
~ ~ ~ ~ ~ ~ ~ 2009 ~ ~ ~ ~ ~ ~ ~
Feb 8, 2009 ... This week has been dominated by questions of replication and of what standards are required to serve the interests of transparency and/or science (not necessarily the same thing).
Possibly a recent example of replication would be helpful in showing up some of the real (as opposed to manufactured) issues that arise.
The paper I’ll discuss is one of mine, but in keeping with our usual stricture against too much pro-domo writing, I won’t discuss the substance of the paper (though of course readers are welcome to read it themselves). Instead, I’ll focus on the two separate replication efforts I undertook in order to do the analysis.
The paper in question is Schmidt (2009, IJoC), and it revisits two papers published in recent years purporting to show that economic activity is contaminating the surface temperature records – specifically de Laat and Maurellis (2006) and McKitrick and Michaels (2007). ...
Data-as-used vs. pointers to online resources {...}
Data updates {...}
Processing {...}
Replication {...}
Science {...}
Bottom line {...}
Despite minor errors in the printed description of what was done and no online code or data, my replication of the dLM07 analysis and it’s application to new situations was more thorough than I was able to do with MM07 despite their more complete online materials. Precisely because I recreated the essential tools myself, I was able to explore the sensitivity of the dLM07 results to all of the factors I thought important.
While I did replicate the MM07 analysis, the fact that I was dependent on their initial economic data collation means that some potentially important sensitivities did not get explored. In neither case was replication trivial, though neither was it particularly arduous. In both cases there was enough information to scientifically replicate the results despite very different approaches to archiving. I consider that both sets of authors clearly met their responsibilities to the scientific community to have their work be reproducible.
However, the bigger point is that reproducibility of an analysis does not imply correctness of the conclusions. This is something that many scientists clearly appreciate, and probably lies at the bottom of the community’s slow uptake of online archiving standards since they mostly aren’t necessary for demonstrating scientific robustness (as in these cases for instance). In some sense, it is a good solution to a unimportant problem.
For non-scientists, this point of view is not necessarily shared, and there is often an explicit link made between any flaw in a code or description however minor and the dismissal of a result. However, it is not until the “does it matter?” question has been fully answered that any conclusion is warranted. The unsatisfying part of many online replication attempts is that this question is rarely explored.
To conclude? Ease of replicability does not correlate to the quality of the scientific result.
And oh yes, the supplemental data for my paper are available here.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
Sep 30, 2009 ... Interesting news this weekend. Apparently everything we’ve done in our entire careers is a “MASSIVE lie” (sic) because all of radiative physics, climate history, the instrumental record, modeling and satellite observations turn out to be based on 12 trees in an obscure part of Siberia. Who knew?
Indeed, according to both the National Review and the Daily Telegraph (and who would not trust these sources?), even Al Gore’s use of the stair lift in An Inconvenient Truth was done to highlight cherry-picked tree rings, instead of what everyone thought was the rise in CO2 concentrations in the last 200 years. ...
... The target de jour is a particular compilation of trees (called a chronology in dendro-climatology) that was first put together by two Russians, Hantemirov and Shiyatov, in the late 1990s (and published in 2002).
This multi-millennial chronology from Yamal (in northwestern Siberia) was painstakingly collected from hundreds of sub-fossil trees buried in sediment in the river deltas. They used a subset of the 224 trees they found to be long enough and sensitive enough (based on the interannual variability) supplemented by 17 living tree cores to create a “Yamal” climate record.
{...}
McIntyre has based his ‘critique’ on a test conducted by randomly adding in one set of data from another location in Yamal that he found on the internet. People have written theses about how to construct tree ring chronologies in order to avoid end-member effects and preserve as much of the climate signal as possible. Curiously no-one has ever suggested simply grabbing one set of data, deleting the trees you have a political objection to and replacing them with another set that you found lying around on the web.
The statement from Keith Briffa clearly describes the background to these studies and categorically refutes McIntyre’s accusations. ...
What is clear however, is that there is a very predictable pattern to the reaction to these blog posts that has been discussed many times. As we said last time there was such a kerfuffle:
"However, there is clearly a latent and deeply felt wish in some sectors for the whole problem of global warming to be reduced to a statistical quirk or a mistake. This led to some truly death-defying leaping to conclusions when this issue hit the blogosphere. ..."
{...}
{from the conclusion}
Peer-review is nothing sinister and not part of some global conspiracy, but instead it is the process by which people are forced to match their rhetoric to their actual results. You can’t generally get away with imprecise suggestions that something might matter for the bigger picture without actually showing that it does. It does matter whether something ‘matters’, otherwise you might as well be correcting spelling mistakes for all the impact it will have.
~ ~ ~ ~ ~ ~ ~ 2010 ~ ~ ~ ~ ~ ~ ~
Jan 8, 2010 ... Guest Commentary by John Fasullo, Kevin Trenberth and Chris O’Dell
A recent paper by Lindzen and Choi in GRL (2009) (LC09) purported to demonstrate that climate had a strong negative feedback and that climate models are quite wrong in their relationships between changes in surface temperature and corresponding changes in outgoing radiation escaping to space. This publication has been subject to a considerable amount of hype, for instance apparently “[LC09] has absolutely, convincingly, and irrefutably proven the theory of Anthropogenic Global Warming to be completely false.” ...
{...}
With the hype surrounding the manuscript, one would think that the article provides a sound, rock solid basis for a reduced climate sensitivity. However, our examination of the study’s methods demonstrates that this is not the case. In an article in press (Trenberth et al. 2010 (sub. requ.), hereafter TFOW), we show that LC09 is gravely flawed and its results are wrong on multiple fronts. These are the major issues we found:
- The LC09 results are not robust. {...}
- The result one obtains in estimating the feedback by this method turns out to be heavily dependent on the endpoints chosen. [edit] In TFOW we show that the apparent relationship is reduced to zero if one chooses to displace the endpoints selected in LC09 by a month or less. So with this method the perceived feedback can be whatever one wishes it to be, and the result obtained by LC09 is actually very unlikely. This is not then really indicative of a robust cloud feedback.
LC09 misinterpret air-sea interactions in the tropics {...}
More robust methods show no discrepancies between models and observations {...}
LC09 have compared observations to models prescribed with incomplete forcings {...}
LC09 incorrectly compute the climate sensitivity {...}
While climate models are known to struggle with many aspects of tropical climate, especially in regards to its coupled variability, the problems claimed by LC09 are not among them. Forster and Gregory [2006] and Murphy et al. [2009] address changes in the energy budget with surface temperatures for a much larger domain and present a much more complete and defensible analysis and discussion of issues. They demonstrate that recent observed variability indeed supports a positive shortwave cloud feedback. ...
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Apr 7, 2010 ... A new popular sport in some media these days is “climate scientist bashing”. Instead of dealing soberly with the climate problem they prefer to attack climate scientists, i.e. the bearers of bad news. The German magazine DER SPIEGEL has played this game last week under the suggestive heading “Die Wolkenschieber” – ...
Temperature data
Cynically and inhumanely the article sets off with remarks on our British colleague Phil Jones.
The authors extensively revel in sentences like this: ...
According to DER SPIEGEL “the entire profession” of climate science “based much of its work on his [Jones'] research” and “almost every internal debate among the climate popes passed through his computer”.
{...]
There is a whole set of other data of global temperature, e.g. the data from NASA which is based on weather stations (and which I prefer for various reasons) or data from NOAA or the satellite data from RSS or the UAH. As is always scientifically useful, important conclusions are based not on one single set of data but on the fact that a whole range of competing scientific groups find consistent results, using different methods (see Figure).
According to DER SPIEGEL Jones has erased raw data and is “an activist or missionary who views ‘his’ data as his personal shrine” who “is intent on protecting it from the critical eyes of his detractors”. However, Jones is neither the producer and owner nor the archivist of these data – it is simply data from the national weather agencies, who also are responsible for its archiving or for the question to whom and under what circumstances they may be passed on. The majority of these data is freely accessible online. ...
{...}
The ever-popular “hockey stick” discussion
DER SPIEGEL resurrects one of the oldest shelf-warmers of the “climate skeptics”: the hockey stick debate and a series of flawed accusations with it. ...
{...}
Tropical storms
Under the subheading “The Myth of the Monster Storm” the SPIEGEL article reports on a “hurricane war” amongst US climate scientists ...
Long story short, fewer but heavier tropical storms can be expected. By the way, the potential destructiveness of storms increases more steeply than the wind velocities; a 2-11% higher speed means a 6-37% higher destructiveness. (Emanuel 2005). ...
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IPCC mistakes
According to DER SPIEGEL “more and more mistakes, evidence of sloppy work and exaggerations in the current IPCC report are appearing”. We already investigated this and came to the conclusion that of the mistakes discussed excitedly in the media, nothing much remains except for the Himalaya mistake. The SPIEGEL does not have anything else to offer either – it counts “Jones’ disputed temperature curve” as one of them; apart from that “the supposed increase in natural disasters” – wrongly so as we have already showed (in German) reacting to an article published in Die Welt which claimed the same. ...
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What is it all about?
SPIEGEL defames some of the best scientists worldwide, who not least for this reason have become prime targets for the “climate skeptics”. ...
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Jul 22, 2010 ... If you don’t know much about climate science, or about the details of the controversy over the “hockey stick,” then A. W. Montford’s book The Hockey Stick Illusion: Climategate and the Corruption of Science might persuade you that not only the hockey stick, but all of modern climate science, is a fraud perpetrated by a massive conspiracy of climate scientists and politicians, in order to guarantee an unending supply of research funding and political power. That idea gets planted early, in the 6th paragraph of chapter 1. ...
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{That would be Mr. Bishop Hill Climate Skeptic Blog A.W.Montford}
Montford’s hero is Steve McIntyre, portrayed as a tireless, selfless, unimpeachable seeker of truth whose only character flaw is that he’s just too polite.
McIntyre, so the story goes, is looking for answers from only the purest motives but uncovers a web of deceit designed to affirm foregone conclusions whether they’re so or not — that humankind is creating dangerous climate change, the likes of which hasn’t been seen for at least a thousand or two years. McIntyre and his collaborator Ross McKitrick made it their mission to get rid of anything resembling a hockey stick in the MBH98 (and any other) reconstruction of past temperature.
Principal Components
... McIntyre & McKitrick (hereafter called “MM”) claimed that the PCA used by MBH98 wasn’t valid because they had used a different “centering” convention than is customary. It’s customary to subtract the average value from each data series as the first step of computing PCA, but MBH98 had subtracted the average value during the 20th century.
When MM applied PCA to the North American tree-ring series but centered the data in the usual way, then retained 2 PC series just as MBH98 had, lo and behold — the hockey-stick-shaped PC wasn’t among them! One hockey stick gone.
Or so they claimed. In fact the hockey-stick shaped PC was still there, but it was no longer the strongest PC (PC1), it was now only 4th-strongest (PC4). This raises the question ...
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Different, yes. Completely, no.
As another example, Montford makes the claim that if you eliminate just two of the proxies used for the MBH98 reconstruction since 1400, the Stahle and NOAMER PC1 series, “you got a completely different result — the Medieval Warm Period magically reappeared and suddenly the modern warming didn’t look quite so frightening.”
That argument is sure to sell to those who haven’t done so. But I have. I computed my own reconstructions by multiple regression, first using all 22 proxy series in the original MBH98 analysis, then excluding the Stahle and NOAMER PC1 series. Here’s the result with all 22 proxies (the thick line is a 10-year moving average):
Certainly the result is different — how could it not be, using different data? — but calling it “completely different” is just plain wrong. Yes, the pre-20th century is warmer with the 15th century a wee bit warmer still — but again, how could it not be when eliminating two hand-picked proxy series for the sole purpose of denying the unprecedented nature of modern warming? ....
Beyond Reason
Another of McIntyre’s targets was the Gaspe series, referred to in the MBH98 data as “treeline-11.” It just might be the most hockey-stick shaped proxy of all. This particular series doesn’t extend all the way back to the year 1400, it doesn’t start until 1404, so MBH98 had extended the series back four years by persistence — taking the earliest value and repeating it for the preceding four years. This is not at all an unusual practice, and — let’s face facts folks — extending 4 years out of a nearly 600-year record on one out of 22 proxies isn’t going to change things much.
But McIntyre objected that the entire Gaspe series had to be eliminated because it didn’t extend all the way back to 1400. This argument is downright ludicrous — what it really tells us is that McIntyre & McKitrick are less interested in reconstructing past temperature than in killing anything that looks like a hockey stick.
McIntyre also objected that other series had been filled in by persistence, not on the early end but on the late end, to bring them up to the year 1980 (the last year of the MBH98 reconstruction). Again, this is not a reasonable argument. Mann responded by simply computing the reconstruction you get if you start at 1404 and end at 1972 so you don’t have to do any infilling at all. The result: a hockey stick. ...
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The hockey stick is so thoroughly imprinted on the actual data that what’s truly impressive is how many things you have to get rid of to eliminate it. There’s a scientific term for results which are so strong and so resistant to changes in data and methods: robust.
Cynical Indeed
Montford doesn’t just criticize hockey-stick shaped proxies, he bends over backwards to level every criticism conceivable. ...
Face-Palm
The willingness of Montford and McIntyre to level any criticism which might discredit the hockey stick just might reach it's zenith in a criticism which Montford repeats, but is so nonsensical that one can hardly resist the proverbial “face-palm.”
Montford more than once complains that hockey-stick shaped proxies dominate climate reconstructions — unfairly, he implies — because they correlate well to temperature.
Duh.
Guilty
Criticism of MBH98 isn’t restricted to claims of incorrect data and analysis, Montford and McIntyre also see deliberate deception everywhere they look. This is almost comically illustrated by ...
Conspiracies Everywhere
Montford also goes to great lengths to accuse a host of researchers, bloggers, and others of attempting to suppress the truth and issue personal attacks on McIntyre. The “enemies list” includes RealClimate itself, ...
Also implicated are William Connolley for criticizing McIntyre on sci.environment and James Annan for criticizing McIntyre and McKitrick. In a telling episode of conspiracy theorizing, we are told that their “ideas had been picked up and propagated across the left-wing blogosphere.” Further conspirators, we are informed, include Brad DeLong and Tim Lambert. And of course one mustn’t omit the principal voice of RealClimate, Gavin Schmidt. ...
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The conspiracy doesn’t end with the hockey team, climate researchers, and bloggers. It includes the editorial staff of any journal which didn’t bend over to accommodate McIntyre, including Nature and GRL which are accused of interfering with, delaying, and obstructing McIntyre’s publications.
Spy Story
The book concludes with speculation about the underhanded meaning of the emails stolen from the Climate Research Unit (CRU) in the U.K. It’s really just the same quote-mining and misinterpretation we’ve heard from many quarters of the so-called “skeptics.” Although the book came out very shortly after the CRU hack, with hardly sufficient time to investigate the truth, the temptation to use the emails for propaganda purposes was irresistible. Montford indulges in every damning speculation he can get his hands on. ...
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concluding thought:
"The only corruption of science in the “hockey stick” is in the minds of McIntyre and Montford. They were looking for corruption, and they found it. Someone looking for actual science would have found it as well.
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Feb 22, 2011 ... Abuse of the UK libel laws is so commonplace as to require no real introduction (but see the Campaign for libel reform for more details). ...
We received this letter on Friday:
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From: Bill Hughes Cc: Sonja Boehmer-Christiansen Subject:: E&E libel Date: 02/18/11 10:48:01
Gavin, your comment about Energy & Environment which you made on RealClimate has been brought to my attention:
“The evidence for this is in precisely what happens in venues like E&E that have effectively dispensed with substantive peer review for any papers that follow the editor’s political line. ”
To assert, without knowing, as you cannot possibly know, not being connected with the journal yourself, that an academic journal does not bother with peer review, is a terribly damaging charge, and one I’m really quite surprised that you’re prepared to make. And to further assert that peer review is abandoned precisely in order to let the editor publish papers which support her political position, is even more damaging, not to mention being completely ridiculous.
At the moment, I’m prepared to settle merely for a retraction posted on RealClimate. I’m quite happy to work with you to find a mutually satisfactory form of words: I appreciate you might find it difficult.
I look forward to hearing from you.
With best wishes
Bill Hughes
Director Multi-Science Publsihing [sic] Co Ltd
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The comment in question was made in the post “From blog to Science” and the full context was:
"The many existing critiques of peer review as a system (for instance by Richard Smith, ex-editor of the BMJ, or here, or in the British Academy report), sometimes appear to assume that all papers arrive at the journals fully formed and appropriately written. They don’t. The mere existence of the peer review system elevates the quality of submissions, regardless of who the peer reviewers are or what their biases might be.
The evidence for this is in precisely what happens in venues like E&E that have effectively dispensed with substantive peer review for any papers that follow the editor’s political line – you end up with a backwater of poorly presented and incoherent contributions that make no impact on the mainstream scientific literature or conversation. It simply isn’t worth wading through the dross in the hope of finding something interesting."
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The point being that if the ‘peer-review’ bar gets lowered, the result is worse submissions, less impact and a declining reputation. Something that fits E&E in spades. This conclusion is based on multiple years of evidence of shoddy peer-review at E&E and, obviously, on the statements of the editor, Sonja Boehmer-Christiansen.
{Also see: "Energy and Environment – 'journal of choice for climate skeptics' Analysing the 900+ skeptic papers part III" | by Christian Hunt | 21 Apr 2011 www.carbonbrief.org/blog/2011/04/energy-and-environment-900-papers}
... She was quoted by Richard Monastersky in the Chronicle of Higher Education (3 Sep 2003) in the wake of the Soon and Baliunas fiasco:
"The journal’s editor, Sonja Boehmer-Christiansen, a reader in geography at the University of Hull, in England, says she sometimes publishes scientific papers challenging the view that global warming is a problem, because that position is often stifled in other outlets. “I’m following my political agenda — a bit, anyway,” she says. “But isn’t that the right of the editor?”
So the claim that the ‘an editor publishes papers based on her political position’ while certainly ‘terribly damaging’ to the journal’s reputation is, unfortunately, far from ridiculous.
Other people have investigated the peer-review practices of E&E and found them wanting. Greenfyre, dissecting a list of supposedly ‘peer-reviewed’ papers from E&E found that: ...
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Mar 9, 2011 ... Eugene Wahl asked us to post a statement related to some incorrect claims circulating in the blogosphere:
~ "The Daily Caller blog yesterday contained an inaccurate story regarding a correspondence that was part of the emails hacked from East Anglia University Climate Research Unit (CRU) in November 2009.
For the record, while I received the email from CRU as forwarded by Dr. Mann, the forwarded message came without any additional comment from Dr. Mann; there was no request from him to delete emails. At the time of the email in May 2008, I was employed by Alfred University, New York. I became a NOAA employee in August 2008.
The emails I deleted while a university employee are the correspondence I had with Dr. Briffa of CRU regarding the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, all of which have been in the public domain since the CRU hack in November 2009.
This correspondence has been extensively examined and no misconduct found. As a NOAA employee, I follow agency record retention policies and associated guidance from information technology staff.
Dr. Eugene R. Wahl
March 9, 2011"
Our comments
These claims are simply the latest attempt to try and manufacture scandals and smear scientists, particularly Mike Mann, based on the UEA emails. The story appears likely to have come from Senator Inhofe’s office who presumably had access to the transcripts taken by the NOAA Office of the Inspector General (whose investigation found no evidence of any wrongdoing by NOAA employees). The story was planted with Steve McIntyre, Anthony Watts, and Chris Horner, and then linked to by Inhofe’s office to provide a little plausible denialability – a rather blatant media spin operation.
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... So what is the actual issue at the heart of this? A single line in the IPCC AR4 report (p466) which correctly stated that “Wahl and Ammann (2006) also show that the impact [of the McIntyre and McKitirck critique] on the amplitude of the final reconstruction [by MBH98] was small (~0.05C)”. This was (and remains) true. ...
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~ "Steve these data were produced by Swedish and Russian colleagues – will pass on your message to them
cheers, Keith ~"
~ "Steve has an amnesia. I had sent him these data at February 2, 2004 on his demand." ~
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