Bob Carter on Global Warming

Michael Duffy has followed up his radio show that misrepresented the science of global warming with more of the same. He had Bob Carter on this time and Carter trotted out all the favourite falsehoods of the global warming sceptics. Actually, Carter complains about being called a sceptic:

Such persons, and myself as you introduced me, are often termed ‘sceptics’ and that’s meant to be a term of denigration, but I’m a scientist…it’s my job to be a sceptic, Michael, and those who are not sceptical towards human-caused global warming or, indeed, towards any other fashionable environmental concern, are acting in unscientific manner…religious, even.

If “global warming sceptic” has become a term of denigration, it’s because of the way they have conducted themselves, dismissing real science on the flimsiest of grounds. I guess I’ll use the more accurate “global warming denialist” to describe Carter.

Carter offers up the usual misrepresentations of the science: urban heat islands contaminate the surface record (no they don’t), equivocation about the word “consensus”, the “hockey stick” is broken (no), ice cores show that warming precedes increases in C02 (only partly), the IPCC summary does not reflect the body of the report (yes it does).

One particular misrepresentation is particularly troubling. Carter claims:

[the surface record] conflicts with independent estimates or measurements that we have of changing temperature made in the atmosphere by satellites and weather balloons. They show very little net change over the last 30 or 40 years.

But the satellite data shows significant warming over the past 30 years. The only discrepancy is that some analyses find only half as much warming as the surface record, while others show a similar amount of warming. It is wrong to pretend that disagreement somehow proves that there hasn’t been any warming.

I remonstrated with Carter when he made similar claims in a Tech Central Station article last year. Here is what he wrote in reply:

There is no conflict between the two following statements, and I stand by both of them.

“There is indeed a small, statistically significant trend.(in the MSU data as analyzed by e.g. Christy et al., 2003)”

and

“The (MSU data) show virtually no long-term trend of temperature increase despite the increased carbon dioxide levels over the last 25 years”

The first is a statistical statement. The second is a statement of scientific judgement which takes into account, amongst other factors, the statistical result.

The sort of technical detail in which you are seeking to discuss the MSU data is most usefully conducted in the relevant professional journals. For reasons of length as much as any other, it is in general not possible to go into such details in an editorial piece written for the general public. That accepted, of course it becomes even more important that the writers of such pieces take particular care with their words. That I have tried to do, and I am sorry if it has not been to your satisfaction.

By coincidence, an interesting new article on MSU results has just come out in Nature (attached). It adds some weight to your evident belief that atmospheric temperatures are rising. On the other hand, many will be concerned that it has proved necessary to selectively manipulate the data to achieve the result. Earlier attempts to make such corrections are acknowledged to have failed.

I shall be interested to see what the expert atmospheric scientists make of Qiang’s study, whilst rather doubting that it will prove to be the last word on the subject.

As I said last time, what one makes of the MSU results (i) depends upon the date and authorship of the paper one chooses to trust; (ii) requires that allowance be made for exceptional events such as the 1998 El Nino; and (ii) will be much clearer when we have another 20 years of data.

So Carter is well aware that the satellite data shows warming but did not mention this on the radio show.

John Quiggin has more on the Duffy and Carter show.

Comments

  1. #1 Yelling
    April 15, 2005

    I found this comment interesting “I shall be interested to see what the expert atmospheric scientists make of Qiang’s study, whilst rather doubting that it will prove to be the last word on the subject.

    I suspect he was waiting for a paper by Spencer and Christy or some other rebuttal. However as far as I know there was only one response to Fu by some people out of Hadley. I thought Fu’s response was appropriate. Scott Church has done some work in this are and may know of more.

    Very few things are final in science so I am sure that changes to Fu’s work will come, but for now it seems to be fairly well established.

  2. #2 Geoff
    April 15, 2005
  3. #3 Dano
    April 15, 2005

    It’s rare that you get a guy who parrots all the arguments in one piece – it makes it convenient to keep track and see what gets recycled.

    D

  4. #4 Scott Church
    April 16, 2005

    I haven’t had time yet to review the Duffy radio show, but for what it’s worth Mr. Carter’s remarks are somewhat more reasonable than those of most global warming “denialists”. He is rightly aware of the importance of sticking to the peer-reviewed literature (which few skeptics do these days), and he is willing to acknowledge the work of Chiang Fu as worthy of consideration. But beyond that, he’s done some side-stepping on the details.

    First, like nearly all other skeptics he chooses to cite only the UAH work in reference to MSU determined troposphere temperatures (Christy et al., 2003). The version he cites if Version 5.0 of their MSU products. He omits the latest published version, 5.1 (Christy & Norris, 2004) which given the longer period, and the direction that we all know this is heading in, gives higher trends. He carefully avoids mentioning RSS Version 1.0 (Mears et al., 2003) or any of the latest RSS results which can be viewed at the RSS Web Site. He also fails to mention the work of Prabhakara et al. (1999, 2000) or Vinnikov & Grody (2004). Some of these products are stronger than others–notably the RSS products. The RSS work is every bit as well characterized as the UAH work, and yields higher trends. The chief difference between the two is in how each product handles error correction — most notably diurnal drift (east-west drifts in satellite orbit that appear as false warming or cooling depending on the direction), and instrument body effect (drifts in the temperature of the onboard “hot target” the MSU’s use to calibrate their definition of a degree Kelvin) — and how they “merge” the records of the individual satellites into a single trendable record. Christy et al., cited exclusively by Carter and virtually all other skeptics, chose to omit some of the satellite records in an attempt to minimize the intersatellite differences in record (a few of the satellites, NOAA-9 all satellite data and did their merging so as to minimize the standard deviation in the residuals (the scatter remaining after a least-squares trend fit to the data). The former method yields a lower trend – and so is favored by skeptics. The latter however uses more of the actual record and minimizes the actual scatter in the real complete record. There are strengths and weaknesses to both approaches, but the mere fact that two different, and valid, analysis methods give disparate results should give careful scientists pause before leaving behind all they have, taking up a cross, and following one specific product.

    As for the “weather balloons” (radiosondes), that is a whole other jungle of issues. These records have issues of their own, and while they provide a valuable, and mostly independent record, the limitations of those records badly obviate their ability to vindicate any single MSU product. Briefly, these include incomplete coverage (less than half of the globe has acceptable sonde coverage), incomplete historical records, changes in equipment and method in any given record, actual moving of stations, equipment failures, detection issues of their own, and last but not least, the fact that they are not even measuring the same thing as MSU’s. MSU packages are passive microwave radiometers that measure the “bulk”, or average, temperature of a whole layer of the atmosphere (depending on the channel used, the middle troposphere, the lower troposphere, or the stratosphere). Radiosonde packages “spot measure” temperatures at specific altitudes from a rising balloon (which by the way, may drift in the breeze from its launch location, and considerably). These are not the same and each must be corrected to make one look like the other. There are issues with this too.

    In all the skeptic literature I’ve immersed myself in over the last decade, I have yet to see any that addresses these issues to any appreciable degree (the best of them only mention one or two in passing). Beyond this, there is one other factor — one that I have never seen addressed by any skeptic commentary or analysis. The main differences in MSU measured global troposphere trends, as measured by Christy et al. and Mears et al., are driven mainly by differences in isolated regions, most notably the high southern latitudes and in particular the southern Pacific. Guess what — the high southern latitudes also happen to be where radiosonde coverage is at its worst, and the southern Pacific where the differences are most apparent, has almost no coverage. By far, where the radiosonde coverage is at its best, the northern hemisphere in particular, the MSU products of UAH which skeptics cite for their lower trends, and the RSS products that give higher ones, largely agree — and these both show considerable, and problematic warming.

    So if I ever decide to by waterfront property in eastern Antarctica, I might take some comfort from skeptic arguments. But as long as I live where the bulk of the human race does is irrelevant, and the fact that they avoid any and all discussion of these issues does not give me confidence in either their thoroughness or their objectivity.

    In regards to Chiang Fu, it’s to his credit that Carter is willing to consider it, even if he avoided mentioning it on the Duffy show. The mere fact that he’ll face it is more than most skeptics will ante up to these days. But his remarks when corresponding to Tim are off the mark.

    It adds some weight to your evident belief that atmospheric temperatures are rising. On the other hand, many will be concerned that it has proved necessary to selectively manipulate the data to achieve the result. Earlier attempts to make such corrections are acknowledged to have failed.

    But Fu’s team was not “selective” in any way. Their work was based on the well known fact that decreasing temperature trends in the lower stratosphere are being aliased into the MSU middle troposphere trend. This as been known for years, and is clearly visible in Christy’s own work as well as that of every other MSU and radiosonde product out there. Fu’s team quantified the impact by using radiosonde data first from the “LKS” sonde network (Fu et al., 2004; Lanzante et al., 2003) and then from other products, to derive a correction that would remove the stratospheric contamination. This is hardly “manipulation” of data — in fact, the sonde dataset they originally used to derive their corrections was the very same one skeptics most often cite as “vindication” of the Christy et al. trends they believe. The chief criticism Christy and a few others have leveled at the Fu method is that statistical methods (specifically, a global least squares fit) applied to data from one MSU channel (MSU4 – lower stratosphere) are used with the sonde-derived correction function, to correct the MSU data from another channel (MSU2 – middle troposphere). Critics argue that the two channels (and the layers they measure) can trend differently both temporally and by region, and thus can lead to corrections that vary widely both temporally and by region. Technically this is true, but less impactful then they think for two reasons. First, other MSU and sonde data, including that which they cite most, shows that during the length of the satellite record the lower stratosphere has trended regionally and temporally in a much more uniform manner than the troposphere has (the most notable exceptions being spikes from the El Chicon and Pinatubo eruptions), so this is less damaging than skeptics believe it is. Second, the criticism of regional and temporal sensitivity applies every bit as much to the uncorrected MSU troposphere record itself. It is difficult to argue against the Fu method on this account without also raising the same questions about the whole tropospheric temperature record in itself — which skeptics are, of course, unwilling to do because they believe it to be an important arrow in their quiver.

    All in all, skeptic treatment of troposphere temperatures as measured by MSU’s and radiosondes, is shallow at best and downright deceptive at worst. I recently dealt with this subject at length in a review of the upper-air record and a review of how skeptics have abused it.

    REFERENCES

    Christy, J.R., R.W. Spencer, W.B. Norris, and W.D. Braswell. 2003: Error estimates of Version 5.0 of MSU-AMSU bulk atmospheric temperatures. J. Atmos. And Oc. Tech., 20, 613-629.

    Christy, J.R. and W.B. Norris. 2004. What may we conclude about global tropospheric temperature trends? Geophys. Res. Lett., 31, L06211, doi:10.1029/2003GL019361.

    Fu, Q., C.M. Johanson, S.G. Warren, D.J. Seidel. 2004. Contribution of stratospheric cooling to satellite-inferred tropospheric temperature trends. Nature, 429, (6987), 55-58.

    Fu, Q., and C.M. Johanson. 2004: Stratospheric Influences on MSU-Derived Tropospheric Temperature Trends. J. Climate, Dec. 15, 2004.

    Lanzante, J.R., S.A. Klein, D.J. Seidel. 2003: Temporal homogenization of monthly radiosonde temperature data. Part I: Methodology. J. Climate, 16(2), 224-240.

    Lanzante, J.R., S.A. Klein, D.J. Seidel. 2003: Temporal homogenization of monthly radiosonde temperature data. Part II: Trends, sensitivities and MSU comparison. J. Climate, 16(2), 241-262.

  5. #5 Dano
    April 19, 2005

    I second the motion recognizing Scott Church as da Man, Amateur Division, Murrican District.

    D

  6. #6 Ken Miles
    April 19, 2005

    Motion passed.

  7. #7 TallDave
    April 29, 2005

    What’s your guys’ take on the solar wind/radiation GW theory? It seems pretty credible, credible enough that models not including it should be suspect.

  8. #8 Scott Church
    April 29, 2005

    TallDave, I’m not sure about solar wind/radiation, but there has been a fair amount of research into solar forcing in general, particularly since the middle 20th century, and this includes a number of mechanisms by which solar ultraviolet and cosmic rays may impact solar forcing. The IPCC has a pretty thorough discussion of these and other solar related forcings in the Year 2001 Report, Chapters 6.11.2, 6.11.2.1, and 6.11.2.2. In the last 4 years, none of this has changed significantly to my knowledge. In general, solar forcing, by any means, has been well established to be of minor significance in overall climate forcing since roughly the 50’s. What impact it has is well accounted for by all of the most reliable state-of-the-art models today including GISS SI2000, DOE-PCM, HadCM3, and others. All the best.

  9. #9 iangould
    April 29, 2005

    Talldave

    I haven’t looked in detail at the solar wind theory but my first reaction is that if its so credible how come the GW skeptics are only producing it now when a number of their other favorite claims, such as stratospheric cooling, have been pretty thoroughly discredited?

  10. #10 Tim Lambert
    April 29, 2005

    It’s possible that solar winds have an effect, but they are not a significant factor in current warming. See here.

  11. #11 Louis Hissink
    May 1, 2005

    Tim,

    You are not a scientist. Period..

  12. #12 Tim Lambert
    May 1, 2005

    Err Louis, around here it is customary to offer evidence in support of your claims. I have a PhD in Computer Science. this means I am not a scientist because…

    And how is your claim relevant to this thread?

  13. #13 Louis Hissink
    May 19, 2005

    Er Tim,

    Science is about framing hypotheses, testing them, and on failure, starting afresh.

    As a geologist, most of my waking hours, (at work at least) are occupied with this paradigm.

    Explaining physical reality is the name of the game, if you wish.

    Now you are a computer programmer, pure and simple. You are not in the business of explaining physical reality, you are in the business of making adding machines work, and teaching students how to make them.

    That is the difference.

  14. #14 Nabakov
    May 20, 2005

    Get yer hand off it Louie. You’re just a guy who goes round looking for shit in ground that might make your employers rich. Use computers much in your work? You certainly need ‘em though when FUDding around the internets like this.

    I think folks Louie’s just grumpy ‘cos he’ll soon be replaced by a computer. A 286 probably.

  15. #15 Louis Hissink
    May 20, 2005

    Nabakov,

    I have used 286’s and 186’s. Before that Commodore 64’s and before that Cyber 76 Systems.

    And I know my Unix.

    Now what is your problem?

  16. #16 Nabakov
    May 20, 2005

    No problem Louie. When I’m not hiring and firing pompous old attention-seeking farts like you, I enjoy baiting ‘em instead.

    And before you start huffing and puffing about ad homien attacks, I think we can all agree that you are pompous, old and attention-seeking.

    But yes, it’s true that “fart” may not be the appropriate noun here – and I am to debate that point with you.

    And Tim L, slip me a balacava and I’ll show you what blog schlager play is really all about. There’s no point in being reasonable with the Louies of this world. Give ‘em a few scars instead I say.

  17. #17 Nabakov
    May 20, 2005

    And Tim, a comments spellchecking functin would be handy to.

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