The CCSP report endgame: Temperature Trends in the Lower Atmosphere: Steps for Understanding and Reconciling Differences

So... where to start? Back in the dim and distant days of a year or so ago, or back to the TAR, there was a problem: temperature trends at the surface and upper atmosphere were incompatible with how the models said they should relate: the models said the upper trends should be larger, obs said otherwise. As it happened (see here and here) the models (and the surface record) ended up triumphant (to somewhat oversell it); and the upper air obs got revised.

But in between the recognition of the problem and its resolution, the CCSP decided to convene a panel to look at the problem and see how it might be resolved. But the CCSP was slow and cumbersome, and has only just got round to releasing the third draft (to be fair, it was probably in the course of working for this report that Mears and Wentz found the big error in S+C's MSU dataset). I haven't read the report yet, but I'm guessing from RP Sr's dislike of it (and his response of dissing the authors) that it will come to the obvious conclusions. Oh all right, I'll read some of the abstract:

Previously reported discrepancies between the amount of warming near the surface and higher in the atmosphere have been used to challenge the validity of climate models and the reality of human-induced global warming. Specifically, surface data showed substantial global-average warming, while early versions of satellite data showed little or no warming above the surface. There is no longer evidence of such a discrepancy. This is an important revision to and update of the conclusions of earlier reports from the U.S. National Research Council and the Intergovernmental Panel on Climate Change.

I suspect thats as far as most people will get, since most people don't need to know any more. And from the exec summary: This difference between models and observations may arise from errors that are common to all models, from errors in the observational data sets, or from a combination of these factors. The second explanation is favored, but the issue is still open. Which seems fair enough, but you can see why some people would be unhappy.

But the most fun can be had from reading the list of commenters and then the comments themselves, together with the responses. Those from Douglass are funny, and the responders blow him away. For example:

Douglas ES-8, P13, L262-3, Quote from report: "Since 1979, due to the considerable disagreements between tropospheric data sets, it is not clear whether the troposphere has warmed more than or less than the surface." Comment: Not true. Do Thorne and Free agree? Response: This is true. It is the considered opinion of the expert author team. Thorne is a member of this team, and, of course, he agrees. Free, who has been consulted at numerous times by the author team and who has participated in some of the meetings of the team, also agrees.

Note that the responders don't seem to have troubled themselves to spell Douglass correctly. Douglass wrote some stuff with Singer - e.g. Altitude dependence of atmospheric temperature trends: Climate models versus observation which actually got published by GRL. Speaking of Singer, he too commented, and he too has embarassed himself and gets blown away:

Singer ES-17, P18 line 357-364: We don't see any evidence for the claimed anthropogenic influence in the climate record. The "fingerprint" results claimed in IPCC-SAR have been discredited. Response: The reviewer does not identify "we"? There is a vast literature on fingerprint studies, much of which is reviewed in Chapter 5. None of this literature has been discredited.

Elsewhere, Singer gets "Bottom line: The Reviewer's unsupported assertion is incorrect." Oh Lordy, and *then* he goes on about ozone again: "[Singer:] The observed stratospheric temp decrease is difficult to explain by ozone depletion... Response: Again, the Reviewer simply makes unsupported assertions."

Trenberth also fares somewhat badly in the responses to his comments (for the exec summary; his detailed comments on the chapters look to have been accepted; and his comments on chapter 5 were: "This chapter is pretty good but I only skimmed it" which drew: "Response: Thanks! No change required."), but for different reasons. E.g. T says The UAH record has once again been revised but the new T2LT values are at odds with surface temperature trends. Chapter 4 falls short in not presenting maps of this difference. Accordingly, this dataset ought to also be discounted. Given the UAH algorithm that is designed to minimize trends, this dataset ought to be given lower weight, but no commentary appears on this issue. Throwing out UAH (ie, Spencer and Christy) would remove most of the niggles that remain, but given the panel that wasn't likely (later on we find The question of which satellite dataset is the most accurate... is still an open question subject to several different points of view that were represented on the author team.

Sci.env's own Eric S also comments; as does Haroon Kheshgi, ExxonMobil Research & Engineering Company (which is a bit of fun in itself: I thought Exxon has sworn off actual climate research: it certainly seems very reluctant to talk about it). HK ends up arguing against the use of "strong" in terms of attribution,

MacCracken has a good general comment Overall, from a purely scientific perspective, this assessment provides a very well done scientific overview of the topic. However, this draft does seem to underplay the significance of the most recent papers in helping to resolve the key issues under investigation, specifically in identifying why some of the datasets developed over recent years are very likely to have flaws. which is also my perspective, though I probably couldn't justify it.

Oooooohhh and it gets better: In that the CCSP assessments are intended to provide information for policymakers [given that they are said to be in response to the relevant section of the US Global Change Research Act], this draft of this assessment seems to me seriously deficient in providing a historical perspective of this issue and a critical evaluation of past claims that have been made about the supposed accuracy of the early versions of the datasets and what the available data were purported to indicate about scientific understanding of climate change. For more than a decade, some of the datasets have been purported to be highly accurate and to indicate that the model simulations must have serious shortcomings. This report shows that those claims, which were made not only in the scientific community but were picked up and loudly exclaimed by some politicians and a number of industrial organizations, were based on a seriously flawed analysis because of flaws in the satellite record. I would urge that, at the least, a table or an appendix be added that gives a timeline of the history of the corrections that have had to be made to the satellite record and that indicates the past claims that should therefore be discounted (and that the IPCC rightly did not accept at the time--leading to some misdirected criticism of their careful approach). By golly there's good stuff in there! This open commenting is wonderful.

RP Sr rides his usual hobby horses of regional change and ocean heat content, and gets ignored. After a bit more, they clearly get bored with him when he gets on to the "first order" stuff: Quite frankly, the Reviewer's position on this issue borders on the ludicrous.

But to finish on a happy note, Trenberth says (of chapter 6) Amen to most of this. This is the most important chapter in the whole document. Chapter 6 is dominated by the Met Office (hurrah!) and is called "What measures can be taken to improve our understanding of observed changes?" Well, maybe in another post...

[Update, on a sadder note. RP has completely "jumped the shark" on this one (is that the right expression?). Anyway, he has not one but two more posts on this, and says:

From the abstract, it is clear the removal of an inconvenient data disagreement (the differences in the surface and tropospheric temperature trends) was THE reason for the Committee and the Report. The scientific issues that I raised in my Public Comment were glossed over or ignored, and the conflict of interest issue with respect to the Committee was completely ignored.

If we re-write this somewhat, to replace "removal" with "investigation" or "reconciliation" then the response to the above is "Duh! Of course it was". The title of the report, "Temperature Trends in the Lower Atmosphere: Steps for Understanding and Reconciling Differences" is just a teensy hint, no?]

More like this

William - I posted the comment below on my weblog at…

"William Connelly posts a blog on the CCSP Report

He is correct (despite his personal,inappropriate digs) that most of my comments were ignored. However, that is not how science should work. If you disagree with peer reviewed scientific conclusions (including in the 2005 NRC Report), the approach is to refute in the literature not to dismiss research arbitrarily."

I invite your weblog readers to read my weblog, including my Public Comment on the CCSP Report, for an alternative perspective. (


Roger Sr.

[Thanks for the comment; I'll take a look at your side. In fact I was wrong to say "ignored" - I meant, they didn't change the report in response]

Yeah, and being "disregarded" is ever so much more emotionally fulfilling than just being "ignored." :)

By Steve Bloom (not verified) on 18 Mar 2006 #permalink

William-I posted the specific charge to the CCSP Committee in response to your comments on my weblog. I have reproduced my response below. Your readers can make up their own minds as to the intrepretation of the charge. I can only add that every member of the CCSP Committe accepted the text of the version of Chapter 6 that was sent to the NRC Committee for review in early 2005. The narrowing of the perspective actually came quite late in the process.


"With respect to the charge to the CCSP Committee, I document this at length in my Public Comment (;

The CCSP charge was broader than you have indicated. I have cut and pasted the overview of the charge to the Committee below from….

It includes the evaluation of the global surface and tropospheric temperature trends. but there was supposed to be a focus also on ?four-dimensional temperature structure?. Hence, the need to also include regional tropospheric and surface temperature trend assessments within the Report; an issue that was all but ignored.

?Overview: Description of Topic, Audience, Intended Use, and Questions to Be Addressed

Independently produced data sets that describe the four-dimensional temperature structure from the surface through the lower stratosphere provide different temperature trends. These differences are seen in varying degrees in comparisons of separate in situ (surface and weather balloon) data sets, in comparisons of separate space-based data sets, and in comparisons of individual data sets drawn from the different observational platforms and different trend analysis teams.

This CCSP synthesis and assessment product will address the accuracy and consistency of these temperature records and outline steps necessary to reconcile differences between individual data sets. Understanding exactly how and why there are differences in temperature trends reported by several analysis teams using differing observation systems and analysis methods represents a necessary step in reducing the uncertainties that underlie current efforts focused on the detection and quantification of surface and tropospheric temperature trends. Consequently, this synthesis and assessment product promises to be of significant value to decisionmakers, and to the expert scientific and stakeholder communities. For example, we expect this assessment to be a major contributor to the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (due to be published in 2007). In addition, we expect the information generated will be used by the Global Climate Observing System Atmospheric Observation Panel to help identify effective ways to reduce observational uncertainty.

Recent efforts to address the uncertainties regarding the temperature structure of the lower atmosphere (i.e., from the surface through the lower stratosphere) have included release of a report under the auspices of the National Research Council (NRC) entitled ?Reconciling Observations of Global Temperature Change? (NRC, 2000) and the IPCC Third Assessment Report (IPCC, 2001, pp 101-123). Although these documents provided a great deal of useful information, the complexities of the issue coupled with shortcomings of the available observing systems prevented resolution of a number of fundamental questions, including:

Why do temperatures vary vertically (from the surface to the stratosphere) and what do we understand about why they might vary and change over time?
What kinds of atmospheric temperature variations can the current observing systems measure and what are their strengths and limitations, both spatially and temporally?
What do observations indicate about the changes of temperature in the atmosphere and at the surface since the advent of measuring temperatures vertically?
What is our understanding of the contribution made by observational or methodological uncertainties to the previously reported vertical differences in temperature trends?
How well can the observed vertical temperature changes be reconciled with our understanding of the causes of these changes?
What measures can be taken to improve the understanding of observed changes?
These questions provide the basis for the six main chapters in the synthesis and assessment product. They highlight several of the fundamental uncertainties and differences between and within the individual components of the existing observational and modeling systems. The responses to the questions will be written in a style consistent with major international scientific assessments [e.g., IPCC assessments, and the Global Ozone Research and Monitoring Project (WMO, 1999)]. ?

[I replied at Rogers blog; just so I don't lose this for the future, I said:

I still disagree, and the bits you've quoted above support my view. You say "but there was supposed to be a focus also on "four-dimensional temperature structure"", and support this with "data sets that describe the four-dimensional temperature structure from the surface through the lower stratosphere provide different temperature trends... This CCSP synthesis and assessment product will address the accuracy and consistency of these temperature records and outline steps necessary to reconcile differences between individual data sets." I think you're reading what you want to see. The 4-d bit is only in the blurb; the actual purpos of the report (I've bolded it; hope it comes through) clearly shows that the reports purpose is to address the diffs.

You may well have hoped to get certain things out of this report. Its very obvious though that what everyone else wanted was resolution and/or understanding of the sfc/model/trop problem. -W]

William-I am requesting your response to issue of the warm bias that we have identified in the surface temperature record (see…).

The GRL paper that is the basis for this conclusion was available to the CCSP Committee before they completed their 3rd Draft (I know because I sent to them), yet it was ignored in the Report. This paper directly relates to the reconciliation of the surface and tropospheric temperature trends on the global scale, and thus, even by a narrow interpretation of the charge to the Committee, should have been included in the discussion.

If the scientific conclusions that we have made in our paper are refutable, present scientific evidence of why that is so. If the conclusions are robust, present a reason as to why our paper, and its important consequences in terms of the assessment of a global average surface temperature, were not discussed in the CCSP Report.

This is just one example of the selectiveness of the CCSP Report.

[Hi Roger. I read/skimmed your paper when you first blogged it. I think its interesting, but I don't understand it well enough to make a meaningful comment now. My gut reaction is that it is somewhere between not-quite-relevant and overstated (as the CCSP report answers you: The cited paper by Pielke and Matsui appears to be an idealized calculation for some unspecified extreme nocturnal condition e.g. that might occur over the Prairies or Siberia. Any attempt to quantify this effect globally or over the tropics requires a full assessment of the real mix of weather events that have occurred): but please don't attempt to quiz me on that, since I couldn't give you a good answer.

As a more general comment, trying to "take on" the surface record the way you have done rather risks makeing you look like a s(k)eptic. And yes, of course, there's nothing wrong with writing papers about it; it how you blog about it etc that matters.

Finally, you need to take on Peterson as well as Parker.]

Thanks William for your reply. Just two comments further. First, a 1 watt per meter squared reduction in nocturnal cooling is hardly extreme. Our results apply to any nighttime anywhere. The CCSP response should have included a specific recommendation to assess the issue on the warm bias that we found.

On the investigation of the surface temperature record, since I have been serving as the Colorado State Climatologist for a number of years, I was confronted by questions about the data. When we looked into it, we found that there are quite a few unaddressed serious problems with using this information for constructing long term trends. This is how science works. That does not make me a "skeptic"; it makes me a scientist who is testing hypotheses.

In any case, I have repeatedly urged the replacement of the global surface temperature trend as the icon for global warming, with ocean heat content changes. Even Jim Hansen agrees with this, as he stated when he presented to our National Research Council Committee that produced the 2005 Report.