Monday, August 7, 2017

+Myth: John Christy Thinks There is No Evidence of the Hot Spot

This post is part of a series addressing issues related to the hot spot. The other parts of this series are listed in the "Myths about the Hot Spot" section of the "Quick Scientific Debunking" page.

The outline for this post is as follows:
  1. The Myth and Its Flaw
  2. Context and Analysis
  3. Posts Providing Further Information and Analysis
  4. References

This is the "+References" version of this post, which means that this post contains my full list of references and citations. If you would like an abbreviated and easier to read version, then please go to the "main version" of this post.

References are cited as follows: "[#]", with "#" corresponding to the reference number given in the References section at the end of this post.

1.  The Myth and Its Flaw

Climate models predict that in moist tropical areas, a region of the lower atmosphere will warm more than Earth's surface. This region of greater warming is known as the "hot spot" [1, pages 14 and 14; 3; 15, page 6; 58]. The myth proposes that John Christy, a climate scientist, thinks that there is no evidence of a hot spot.

John Christy is the main proponent of this myth [1 - 6], those others contribute to the myth as well, including Jospeh D'Aleo [1; 2], James Wallace III [1; 2], and bloggers on WattsUpWithThat [7; 8].

The myth's flaw: John Christy knows that there is evidence of the hot spot, since Christy made graphs presenting evidence that passed his test for the hot spot. After making these graphs, Christy changed his hot spot test, instead of admitting that the evidence passed his test. Thus Christy moved the goal-posts in order to avoid publicly stating what he already knew: scientific evidence shows the hot spot exists.

2. Context and Analysis

Earth's atmosphere contains multiple layers. The layer closest to the Earth's surface air is known as the troposphere. Climate models predict that tropospheric warming in the tropics should increase with increasing height [9, page 4; 10 - 13; 14, from 31:01 to 31:48]. See "Myth: The Tropospheric Hot Spot does not Existfor more on the mechanism behind this increased warming; however, knowing this mechanism is not required for understanding the points made in this blogpost.

The aforementioned tropical warming amplification is called the tropical tropospheric hot spot by myth proponents [1, pages 14 and 42; 3; 15, page 6]. So the hot spot I will discuss relates to amplification of warming as one goes from the tropical surface to higher in the tropical troposphere [1, pages 14 and 42; 3; 15, page 6]. This is different from the question of whether the amount or magnitude of observed tropospheric warming matches the amount of warming projected by climate models [15, pages 5 - 7; 16]; I address the "magnitude" issue in "Myth: Santer et al. Show That Climate Models are Very Flawed". Figure 1 depicts the hot spot (amplification of warming with increasing height in the tropics) in response to warming caused by increased solar activity or in response to warming caused by increased carbon dioxide (CO2):

Figure 1: ECHAM3/LSG model (European Center/Hamburg Model 3 / Large Scale Geostrophic coupled atmosphere-ocean climate model) simulation of the atmospheric response to (a) increased solar forcing (from increased solar output) and (b) increased CO2 forcing (from increased CO2 levels). Colored areas indicate significant responses, with darker blues indicating cooling and darker reds indicating warming. The horizontal axis represents latitude, with the tropics being between roughly 30N and 30SThe vertical axis represents altitude, with decreasing atmospheric pressure as altitude increases [17, page 707]. The tropical troposphere lies below 150hPa, while the tropical stratosphere is above 70hPa [18]. Tropical tropospheric warming increases with height in both panels a and b, indicating that the hot spot forms in response to both solar-induced warming and CO2-induced warming. In contrast, strong tropical stratospheric appears in response to CO2-induced warming, but not solar-induced warming. This figure is taken from a 2001 report of the United Nations Intergovernmental Panel on Climate Change (IPCC) [17, page 707].

In August 2016, Christy co-authored the first edition of a non-peer-reviewed blogpost/"report" [1]. In this "report" he presented the following test for the existence for the hot spot:

"Section IV. Tropical Hot Spot Hypothesis Testing
The proper test for the existence of the THS [tropical hot spot] in the real world is very simple. Are the slopes of the three trend lines (upper & lower troposphere and surface) all positive, statistically significant and do they have the proper top down rank order [1, page 14]?"

Let's call this test the tropical hot spot test or the THS test. The THS test makes it clear that the hot spot is about amplified tropical warming with increasing tropospheric height [1, page 14].

Christy never shows that the available data fails the THS test. Instead Christy claimed to subtract out warming caused by the Sun and an ocean cycle known as the El Niño-Southern Oscillation (ENSO). Christy then stated that no significant troposoheric warming remained after this subtraction. And since there was no significant tropospheric warming left, then there was no evidence of the hot spot [1, page 4], according to Christy's reasoning [1, pages 16, 18, 67 and 68]. Christy's reasoning fails for at least two reasons (I discuss these reasons more in section 3.5 of part 1 of "John Christy and the Tropical Tropospheric Hot Spot"):

  • Christy used cumulative indices to correct for solar-induced and ENSO-induced warming [1, page 18]. These indices are "cumulative" because the indices assume that the Earth accumulates energy from solar-induced and ENSO-induced warming, such that a warmer Earth does not radiate more energy. For example, Christy's cumulative ENSO index assumes that when Earth's troposphere warms during an El Niño year, the energy in the troposphere simply accumulates and is passed on to the next year. But this conclusion violates basic physics, as the climate scientist Timothy Osborn points out [19]: a warmer Earth would radiate more energy into space, instead of all the energy just accumulating [20 - 22]. Scientists can observe this increased radiation during a warm El Niño [23 - 25]; the radiation increase occurs largely because El Niño increases cloud cover and these clouds then reflect the solar radiation Earth would otherwise absorb [23; 26]. This cloud-based mechanism compensates [23; 25] for less emission of radiation by clouds during El Niño [27; 28]. Given the defects in Christy's cumulative indices, scientists rarely (if ever) use Christy's indices. In fact, I know of no peer-reviewed scientific paper that uses Christy's cumulative indices. Scientists instead use non-cumulative indices to account for solar-induced and ENSO-induced warming. Even Christy's [1, page 18; 29, page 10] sources applied non-cumulative solar [30; 31; 35 - 38] and ENSO indices [32; 33; 34, page 231; 35 - 42], as did Christy in his peer-reviewed work [31]. These non-cumulative indices are compatible with Earth radiating more energy as Earth warms. When scientists used these non-cumulative indices to correct for ENSO-induced [35 - 42] and solar-induced warming [35 - 38], most of the post-1950s tropospheric and surface warming remained [35 - 42], contrary to the claims Christy made in his blogpost/"report" [1, pages 16, 18, 67 and 68]. And even a representative of the organization Friends of Science, claims that Christy did not appropriately correct for ENSO [60, comment from Ken Gregory in the comments section], despite the fact that Friends of Science deny that the hot spot exists [61].
  • The hot spot may be there before one subtracts out solar-induced and ENSO-induced warming. So it would be non sequitur to infer that the hot spot does not exist, based on Christy's correction for warming caused by the Sun and ENSO.

So the hot spot could still exist even if one assumes (for the sake of argument) that Christy's solar and ENSO corrections are correct. But even if one claims that there is no hot spot after solar and ENSO corrections, that still leaves the question of whether Christy thought the hot spot exists. And it is this question that is the subject of the myth. The myth fails if: 1) Christy claimed that there was no evidence of the hot spot and, 2) Christy knew the hot spot existed. The first edition of Christy's blogpost/"report" met condition 1. Let's move on to condition 2.

After completing the first edition of his "report", Christy further examined data relevant to the hot spot. This process culminated in Christy compiling the figure below between August 2016 and February 28, 2017 for Patrick Michaels' Congressional testimony [43]:

Figure 2: Comparison of the observed tropical warming trend (from latitudes of 20N to 20S) to model-based projections of the warming trend. The horizontal axis shows the rate of warming. The vertical axis shows altitude, with atmospheric pressure decreasing with increasing altitude. The red lines indicate the range of warming projected from models used by the United Nations Intergovernmental Panel on Climate Change (IPCC). The observed warming trend comes from weather balloon data (RICH, RAOBCORE, RATPAC A, and UNSW), satellite data (UAHv6.0, RSSv4.0, NOAAv4.0, and UW), and temperature re-analyses (ERA-I, MERRA2, and JRA-55). The "TMT" inset near the top shows observed mid-tropospheric warming trend from each data source, in comparison to the model projections of this trend [43]. Christy co-authored a November 2017 paper [62, figure 3] and a March 2018 paper that include graphs similar to the one above [75, figure 18].

  • Christy failed to acknowledge that the weather balloon (radiosonde) analyses were likely spuriously cool [44].
  • Christy exaggerated the difference between the models and the satellite data [45].
  • Michaels [43] and Christy claimed [45; 46] that the model-to-data difference is predominately due to a flaw in the models, when this is not the case [44 - 46].

But suppose one takes Christy's figure at face value, for the sake of argument. Then figure 2's model-to-data comparison would not help Christy's case for at least two reasons. First, Christy's "report" argued against using climate models to evaluate the existence of the hot spot in real world observations [1, section 3 on page 14]:

"Section III. Research Design
Unlike some research in this area, this research does not attempt to evaluate the existence of the THS [tropical hot spot] in the real world by using the climate models. This would constitute a well-known error in mathematics and econometrics [...] [1, page 14]."

Second, the divergence between the models and the data would not change the warming pattern present in figure 2's data. The weather-balloon-based warming pattern is one of greater tropical warming with increasing tropospheric height, with a warming maximum in the tropical upper troposphere at ~300 hPa. This overall pattern is consistent with published weather balloon analyses [44; 47 - 52]. So the weather balloon data in figure 2 passes the THS test; Christy's February 28, 2017 figure therefore shows evidence of the hot spot. This means that by February 28, 2017 Christy knew there was evidence showing the hot spot.

In his March 2017 written Congressional testimony, Christy again showed evidence that passes the THS test, with greater tropical warming with increasing tropospheric height [76, page 9]. This is shown in figure 3 below from Christy's testimony:

Figure 3: Comparison of tropical warming trend to model-based projections of the warming trend. The red and blue lines indicate projected warming from models used by the United Nations Intergovernmental Panel on Climate Change (IPCC); the effects of extra greenhouse gases (GHGs, such as CO2) are included in the red line projections, but not in the blue line projections. The gray lines indicate the observed warming trends [29].

Figure 3 involves the same mistakes I noted for figure 2. But more importantly, Christy presented figure 3 in his written March 2017 testimony, after Christy knew there was evidence of the hot spot. Yet Christy did not acknowledge the hot spot present in figure 3 nor the hot spot in his previous figure 2 [29]. Instead, on the pages following figure 3, Christy mentioned [29, pages 10] the first edition of his blogpost/"report" in which he says there was no evidence of the hot spot. So in his Congressional testimony, Christy brazenly cited a blogpost that contradicted his own testimony and what he knew to be true. Weird. But what happened next was even more bizarre.

At this point, you might think that a honest scientist like Christy would admit that there was evidence that passed his THS test, and thus he would admit that there was evidence showing the hot spot. Maybe Christy would do this on April 2017 in the second edition of his non-peer-reviewed, hot spot blogpost/"report" [2]? If you think this, then you have too much confidence in John Christy, as I once did. In his "report's" second edition Christy still claimed there was no evidence of the hot spot [2, page 4], even though he knew the evidence existed. To get away with this, Christy changed the THS test [2, page 14]. This becomes more clear when one compares section IV of the "report's" 2016 first edition with section IV of the "report's" 2017 second edition. 

From the August 2016 first edition:

"Section IV. Tropical Hot Spot Hypothesis Testing
The proper test for the existence of the THS in the real world is very simple. Are the slopes of the three trend lines (upper & lower troposphere and surface) all positive, statistically significant and do they have the proper top down rank order [1, page 14]?"

From the April 2017 second edition, with bolding for the portions different from the August 2016 first edition:

"Section IV. Tropical Hot Spot Hypothesis Testing
The proper test for the existence of the THS in the real world seem [sic] [emphasis added] very simple. Are the slopes of the three trend lines (upper & lower troposphere and surface) all positive, statistically significant and do they have the proper top down rank order? Note that this is a necessary, but not sufficient, condition for THS theory validation. In fact, currently some tropical tropospheric temperature data sets do have statistically significant upward sloping trend slopes [emphasis added] [2, page 14]?"

So between the first and second edition, Christy moved from saying that his test is simple, to claiming that his test seems simple. He then claimed that the THS test provided necessary, but not sufficient, conditions for identifying the hot spot. Yet Christy did not say what would be sufficient conditions for identifying the hot spot. He did not explain why an increasing tropical warming trend from the surface to the lower troposphere to the upper troposphere, would not be sufficient for showing the tropical hot spot. Instead Christy simply modified his testing criteria [2, page 14] when he realized that the data might pass his THS test.

This sort of post hoc, ad hoc modification is known as moving the goalposts. Pseudoscientists and denialists of various stripes often move the goalposts in order to avoid accepting evidence that is inconvenient for their position [53; 54]. For example, many creationists move the goalposts in order to evade accepting evidence of evolution [54]. Similarly so for AIDS denialists who move the goalposts in order to dodge evidence that HIV causes AIDS [53]:

"Pushing Back the Goalpost
Of all the characteristics of deniers, repeatedly nudging back the goalpost—or the threshold of evidence required for acceptance of a theory—is often the most telling. The strategy behind goalpost-moving is simple: always demand more evidence than can currently be provided. If the evidence is then provided at a later date, simply change the demand to require even more evidence, or refuse to accept the kind of evidence that is being offered [53]."

[Some AIDS denialists compare themselves to "skeptics" of anthropogenic global warming (AGW) [ex: 55]. Furthermore, AIDS denialists sometimes publish in the same disreputable venues [56; 57; 63 - 65], and resort to the same irrational tactics, as AGW denialists; hence these two forms of science denialism are often compared [66 - 74]. So I am no longer shocked to see an AGW "skeptic" like Christy employing the same discredited tactics as AIDS denialists.]

"Arguing with science denialists is usually a waste of time. They masquerade as ordinary colleagues who adhere to the overarching goal of science, i.e. to find the best approximations of truth in the matter under consideration. The crucial difference is that your colleagues will accept a scientific statement if provided with sufficiently strong reasons to do so. In contrast, climate science denialists, like other pseudoscientists, tend to be driven by motives that make them impossible to convince, however strong the arguments they are presented with [emphasis added] [67, section 5]."

So it is quite telling that Christy resorted to moving the goalposts in order to avoid acknowledging evidence of the hot spot. Christy is aware that the hot spot exists [43], but he denies that there is evidence of the hot spot [1, page 4; 2 page 4] and he relies on pseudoscientific tactics in order to defend his denial. Yet people, including Christy himself, keep appealing to Christy's claim that there is no evidence of the hot spot [1 - 8]. In fact, Christy makes his blogposts/"reports" on behalf of ICECAP, an organization that uses Christy's hot spot claims to attack the US Environmental Protection Agency's attempts to regulate CO2 emissions [59]. What a farce.

3. Posts Providing Further Information and Analysis

4. References

  1. "On the Existence of a “Tropical Hot Spot" & The Validity of EPA’s CO2 Endangerment Finding"
  2. "On the Existence of a “Tropical Hot Spot” & The Validity of EPA’s CO2 Endangerment Finding, Abridged Research Report, Second Edition"
  4. "What do observational datasets say about modeled tropospheric temperature trends since 1979?"
  5. "McNider and Christy: Why Kerry is flat wrong on climate change"
  7. "The ‘fingerprint’ of global warming doesn’t exist in the real world, study finds"
  9. "Response of the large-scale structure of the atmosphere to global warming"
  10. "Comparing tropospheric warming in climate models and satellite data"
  11. "Physical mechanisms of tropical climate feedbacks investigated using temperature and moisture trends"
  12. "Regional variation of the tropical water vapor and lapse rate feedbacks"
  13. "Elevation-dependent warming in mountain regions of the world"
  14. Ray Pierrehumbert's 2012 video: "Tyndall Lecture: GC43I. Successful Predictions - 2012 AGU Fall Meeting"
  15. "Extended Summary of the Climate Dialogue on the (missing) tropical hot spot"
  17. "Climate change 2001: The scientific basis; Chapter 12: Detection of climate change and attribution of causes"
  18. "Tropical Tropopause Layer" [doi:10.1029/2008RG000267]
  20. "Global monthly precipitation estimates from satellite-observed outgoing longwave radiation"
  21. "An observationally based energy balance for the Earth since 1950"
  22. "An analysis of the dependence of clear-sky top-of-atmosphere outgoing longwave radiation on atmospheric temperature and water vapor"
  23. "ENSO-driven energy budget perturbations in observations and CMIP models"
  24. "Advances in understanding top-of-atmosphere radiation variability from satellite observations"
  25. "Observed changes in top-of-the-atmosphere radiation and upper-ocean heating consistent within uncertainty"
  26. "The ENSO effects on tropical clouds and top-of-atmosphere cloud radiative effects in CMIP5 models"
  28. "Does vertical temperature gradient of the atmosphere matter for El Niño development?"
  29. "U.S. House Committee on Science, Space & Technology, 29 Mar 2017, Testimony of John R. Christy"
  30. "A discussion of plausible solar irradiance variations, 1700‐1992"
  31. "Satellite greenhouse signal"
  32. (accessed June 12, 2017)
  33. "El Niño/Southern Oscillation behaviour since 1871 as diagnosed in an extended multivariate ENSO index (MEI.ext)"
  34. "The role of ENSO in global ocean temperature changes during 1955-2011 simulated with a 1D climate model"
  35. "Deducing multidecadal anthropogenic global warming trends using multiple regression analysis"
  36. "Global temperature evolution 1979–2010"
  37. "Spectrally dependent CLARREO infrared spectrometer calibration requirement for climate change detection"
  38. "Natural variability, radiative forcing and climate response in the recent hiatus reconciled"
  39. "Volcanic contribution to decadal changes in tropospheric temperature"
  40. "Clarifying the roles of greenhouse gases and ENSO in recent global warming through their prediction performance"
  41. "Equilibrium climate sensitivity in light of observations over the warming hiatus"
  42. Foster et al.: "Comment on “Influence of the Southern Oscillation on tropospheric temperature” by J. D. McLean,C. R. de Freitas, and R. M. Carter"
  43. "At what cost? Examining the social cost of carbon"
  44. "Internal variability in simulated and observed tropical tropospheric temperature trends"
  45. "Comparing tropospheric warming in climate models and satellite data"
  46. "Causes of differences in model and satellite tropospheric warming rates"
  47. "Reexamining the warming in the tropical upper troposphere: Models versus radiosonde observations"
  48. "New estimates of tropical mean temperature trend profiles from zonal mean historical radiosonde and pilot balloon wind shear observations"
  49. "Atmospheric changes through 2012 as shown by iteratively homogenized radiosonde temperature and wind data (IUKv2)"
  50. "Homogenization of the global radiosonde temperature dataset through combined comparison with reanalysis background series and neighboring stations"
  51. "Radiosonde bias adjustments- ERA-CLIM2 project; Bias adjustments for radiosonde temperature, wind and humidity from existing reanalysis feedback; Deliverable 4.1 of EU 7FP project ERA-CLIM2 (Grant No. 607029)"
  52. "Warming maximum in the tropical upper troposphere deduced from thermal winds"
  53. "HIV denial in the internet era"
  54. "Irreducible incoherence – a look into the conceptual toolbox of a pseudoscience"
  56. "Questioning HIV/AIDS: Morally reprehensible or scientifically warranted?"
  57. "Environmental effects of increased atmospheric carbon dioxide"
  62. "Satellite bulk tropospheric temperatures as a metric for climate sensitivity"
  66. "Manufactured scientific controversy: Science, rhetoric, and public debate"
  67. "Dealing with climate science denialism: experiences from confrontations with other forms of pseudoscience"
  68. "Denialism: what is it and how should scientists respond?"
  69. "How the growth of denialism undermines public health"
  70. "The ethics of belief, cognition, and climate change pseudoskepticism: Implications for public discourse"
  71. "Science denial as a form of pseudoscience"
  72. "Countering evidence denial and the promotion of pseudoscience in autism spectrum disorder"
  73. "Science denial and the science classroom"
  74. "Science denial: a guide for scientists"
  75. "Examination of space-based bulk atmospheric temperatures used in climate research"