A global temperature

Eli’s post about some of Ross McKitrick’s blunders reminded me that I was involved in a discussion elsewhere when someone highlighted another of his papers called Does a global temperature exist? (with Christopher Essex and Bjarne Andresen). It’s rather old, and Eli’s already covered it, so I won’t say much more about it. Essentially they consider various ways of averaging temperature and conclude that

There is no global temperature.

What I thought I would do is make a slightly different point. In the physical/natural sciences, numbers are used to represent something. In the case of temperature, it’s the average energy per particle. How you manipulate those numbers then depends on what you want to do. If you simply wanted to know the average temperature, you might simply add up the temperatures and divide by the number of measurements. You might, however, need to weight the average if the measurements aren’t all associated with the same volume. If the specific heat capacity has a strong temperature dependence, you might want – instead – to determine the total energy associated with the measurements and then compute the temperature from that. On the other hand, if one was interested in the greenhouse effect, or energy balance, one might define the average temperature as the temperature of a blackbody that has the same flux as the average surface flux on the Earth.

As long as you understand the properties of the system, or know what it is you want to do, you can work out how best to manipulate the numbers. If, however, what you get seems very odd, you might want to check that you haven’t made some kind of blunder, like using Celsius instead of Kelvin (see Eli’s post). I guess the point that I’m getting at is that simply knowing how to manipulate numbers isn’t sufficient if you don’t understand what the numbers represent or don’t have some sense of why you would want to manipulate the numbers in the first place.

Of course, there’s nothing wrong with trying things and getting them wrong. However, typically you would want to learn from your mistakes. It appears that not only does Ross McKitrick not learn from his mistakes, he doesn’t even want them pointed out to others, which seems to rather go against the scientific method. That Ross McKitrick doesn’t take well to criticism also seems reasonably well known. This review of his book Taken by Storm, also with Christopher Essex, starts the concluding paragraph with:

One hesitates to comment on these authors, given their one-size-fits-all reaction to those who disagree: all are simply dupes of the doctrine. But I cannot remember a book that combines so thoroughly tendentiousness with pretensions of objectivity.

Bear in mind that the above refers to the current Chairman of the Global Warming Policy Foundation’s Academic Advisory Council (Essex), and his immediate predecessor (McKitrick). That might explain the Global Warming Policy Foundation’s regular blunders, but I suspect that that is more a feature than a bug.

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52 Responses to A global temperature

  1. There is no global temperature.

    Came by a blog post with the same claim. Especially sad was that all the people writing comments lapped it up. Seemed to a case were you can be sure that engaging is utterly useless.

  2. Eli Rabett says:

    Well, in a formal sense there ain’t, but there sure is a global temperature anomaly and you can define an effective global temperature by measuring the outflow.

  3. semyorka says:

    So we cannot tell if it was colder or not during the last glacial maximum.

  4. appaling says:

    Umm… Perhaps “process the numbers”, not “manipulate the numbers”?

    I know “manipulate” is accurate description, however, it may be misinterpreted if you attach negative value judgement to “manipulate”, which obviously some parties do. Using potentially value-loaded words open up for nefarious quote mining.

  5. I’m not sure I’ve ever heard any scientist use the phrase ‘global temperature’ in isolation. If they have it’s been short for ‘average global temperature’ and has come with more explanation of to what they refer. So it seems to be something of a strawman.

  6. Magma says:

    Other extracts from Deep Thoughts, by Christopher Essex

    Can there be a temperature if there is no observer?

    Atoms… why?

    Coal is delicious.

  7. Brandon Gates says:

    Essex, McKitrick and Andresen (2006) only mention “anomaly” twice, once in “scare quotes”, and then immediately complain that it is physically meaningless, e.g:

    However, chemical, physical or biological processes governed by temperature at r are not functions of temperature other than at r. So if one insists on Ξ defining processes like the melting of glaciers at some location, say, the melting is forced into being a function of temperatures elsewhere on the planet too, which is physically untenable.

    Gee, no kidding guys. That’s why there are gridded products reporting absolute temps, and failing that, the original observations are still available at their most granular level.

    I think the best way I’ve ever seen mean global temperature anomaly described is that it’s an operational definition used as a metric, and is meaningful so long as nobody tries to do publication-quality thermodynamics or radiative physics with it.

  8. John Drayton says:

    Caveat: I’ve only just skimmed this article, but I’ll post my initial thought:
    If “there is no global temperature”, then is there a regional temperature? Is there a city temperature? Surely a city temperature is subject to the same conceptual issues, yet we do find it a very useful number in real life.

  9. Eli,

    Well, in a formal sense there ain’t,

    Indeed, but in that sense there’s no “global” temperature for any complex system so – as john says – it becomes a strawman.

    Okay, “process the numbers” might have been better.

    John Drayton,
    Yes, I think you could apply to anything in which the case the argument essentially becomes “we know nothing”.

  10. MartinM says:

    I see Judith Curry’s got a guest post up on this very subject. Next up: why the earth is actually 6000 years old.

    As for the actual topic, I doubt any of the people pushing the notion that global temperature is meaningless actually believe it. Some of them might believe that they believe it, but if you ask them if, say, the Earth is colder than the Sun, they’ll still have an answer.

  11. Martin,
    Just had a look. It’s another one of those posts where someone with some knowledge hasn’t considered that those who actually work in this field already know, and understand, what they’re trying to claim is some new insight.

  12. BBD says:

    There is no global temperature.

    Contrarians should listen to their own experts more closely. There are, after all, few enough of them. For example, Dr Roy Spencer PhD has this to say in defence of the globally averaged temperature:

    I sometimes hear my fellow climate realists say that a globally-averaged surface temperature has little or no meaning in the global warming debate. They claim it is too ill-defined, not accurately known, or little more than just an average of a bunch of unrelated numbers from different regions of the Earth.

    I must disagree.

    The globally averaged surface temperature is directly connected to the globally averaged tropospheric temperature through convective overturning of the atmosphere. This is about 80% of the mass of the atmosphere. You cannot warm or cool the surface temperature without most of the atmosphere following suit.

    The combined surface-deep layer atmospheric temperature distribution is then the thermal source of most of the infrared (IR) radiation that cools the Earth in response to solar heating by the sun. Admittedly, things like water vapor, clouds, and CO2 end up also modulating the rate of loss of IR to space, but it is the temperature which is the ultimate source of this radiation. And unless the rate of IR loss to space equals the rate of solar absorption in the global average, the global average temperature will change.

    The surface temperature also governs important physical processes, for instance the rate at which the surface “tries” to lose water through evaporation.

    If the globally averaged temperature is unimportant, then so are the global average cloudiness, or water vapor content. Just because any one of these globally-averaged variables is insufficient in and of itself to completely define a specific physical process does not mean that it is not a useful number to monitor.

    Finally, the globally averaged temperature is not just a meaningless average of a bunch of unrelated numbers. This is because the temperature of any specific location on the Earth does not exist in isolation of the rest of the climate system. If you warm the temperature locally, you then will change the horizontal air pressure gradient, and therefore the wind which transports heat from that location to other locations. Those locations are in turn connected to others.

    In fact, the entire global atmosphere is continually overturning, primarily in response to the temperature of the surface as it is heated by the sun. Sinking air in some regions is warmed in response to rising air in other regions, and that rising air is the result of latent heat release in cloud and precipitation systems as water vapor is converted to liquid water. The latent heat was originally picked up by the air at the surface, where the temperature helped govern the rate of evaporation.

    In this way, clouds and precipitation in rising regions can transport heat thousands of kilometers away by causing warming of the sinking air in other regions. Surprisingly, atmospheric heat is continually transported into the Sahara Desert in this way, in order to compensate for the fact that the Sahara would actually be a COOL place since it loses more IR energy to space than it gains solar energy from the sun. (This is because the bright sand reflects much of the sunlight back to space).

    Similarly, the frigid surface temperature of the Arctic or Antarctic in wintertime is prevented from getting even colder by heat transport from lower latitudes.

    In this way, the temperature of one location on the Earth is ultimately connected to all other locations on the Earth. As such, the globally averaged surface temperature — and its intimate connection to most of the atmosphere through convective overturning — is probably the single most important index of the state of the climate system we have the ability to measure.

    Granted, it is insufficient to diagnose other things we need to know, but I believe it is the single most important component of any “big picture” snapshot of climate system at any point in time.

  13. Magma says:

    BBD: Contrarians should listen to their own experts more closely. There are, after all, few enough of them.

    Short enough to list. Keeping it to those with legitimate claims to being 1) physical scientists who 2) work and publish in climate-related fields, I can think of five off the top of my head. I exclude the likes of geologists Ian Plimer, Don Easterbrook and the recently deceased Bob Carter (but I suppose people could put in a weak argument for the long-retired Easterbrook).

    John Christy
    Judith Curry
    Richard Lindzen (retired)
    Roger Pielke Sr. (more contrarian in comments than in publications; retired)
    Roy Spencer

    Any others?

  14. Tadaaa says:

    looks like they have picked their ball up and gone home for tea

  15. Willard says:

    > Next up: why the earth is actually 6000 years old.

    You made me look, MartinM.

  16. anoilman says:

    Magma: You get more if you just keep repeating.

  17. The Very Reverend Jebediah Hypotenuse says:

    From Essex last year. Curry-approved.

    What the dogmatists understand well is eristic argument, after Eris the Greek goddess of discord and chaos. Eristic tactics come to us from the ancient Greek sophists. Eristic methods manifest themselves today in the works of Saul Alinsky. As the goddess’s qualities suggest, they are inherently divisive. The objective is victory, not truth. This is foreign to the training and personalities of most scientists. I, like other scientists, go into debates with a collegial attitude, tolerant of contrary thinking, no matter how wrong it may seem. Freely doubt the ideas; respect the people. When confronted with eristic tactics though, which are often absurd, aggressive, and deeply irrational, we are left gobsmacked. Like any other humans, scientists can speak the language of political nonsense, but they speak it badly. Their famous political naivety makes them easy prey for any political operative. And so we loose against eristic tactics, even when we know they are coming.


    It’s just so sad that scientists are so essentially polite and naive that they always fall victim to sophistry. It’s a miraculous wonder that, as scientists, Essex could even imagine all those strategical words, and Curry could pretend to understand them.

    The ontology of predation and gobsmackery is obviously simple when compared to means, medians, and modes.

  18. Willard says:

    > Eristic methods manifest themselves today in […]

    ClimateBall ™.

    FIFY, Christopher.

  19. WebHubTelescope says:

    Don’t forget Murry Salby in that list. It really is amazing that this select group of misguided atmospheric scientists have written textbooks on this stuff. Here is what I found on Amazon:

    Judith Curry :
    Thermodynamics of Atmospheres and Oceans $117.98
    Encyclopedia of Atmospheric Sciences $2,800.00
    Thermodynamics, Kinetics, and Microphysics of Clouds $115
    Interactions Between Arctic Sea Ice and Atmospheric Boundary Layer in the Presence of Leads $100

    Murry Salby :
    Physics of the Atmosphere and Climate $96
    Fundamentals of Atmospheric Physics (edited by Roger Pielke, Sr) $101
    Stratospheric Constituent Response to Vertically Propagating Equatorial Waves $100

    Richard Lindzen :
    Dynamics in Atmospheric Physics $180
    Atmospheric Tides: Thermal and Gravitational $99
    Semidiurnal Hough Mode Extensions in the Thermosphere and Their Application. $114.70

    Roger Pielke Sr :
    Mesoscale Meteorological Modeling $416.90
    Climate Vulnerability: Understanding and Addressing Threats to Essential Resources $1596

  20. Joshua says:

    ==> “There is no global temperature.”

    So they agree that “the pause” is a meaningless concept?

  21. John Mashey says:

    Regarding Essex, see comment from a year ago, which lists some of the interesting speakers for the U of Western Ontario’s Nerenberg award lecture (applied math):
    Fred SInger
    Sallie Baliunas
    Christopher Monckton

    This includes a video of Monckton’s talk, including introduction by Essex, plus commentary by a blogger with useful information. As I noted, a bit later, all mention of this seemed to have disappeared from the official UWO website … but Wayback saved things.

  22. Marco says:

    Web, please note that your also referring to book series where they were Editors. Curry wrote a few chapters, but was otherwise ‘just’ an Editor on “Encyclopedia of Atmospheric Sciences”

    Pielke was the EiC for the “Climate Vulnerability” series.

  23. Ray says:

    @Victor Venema posted the Leo Hickman tweet, and what I found by following some of the replies is that apparently 2015 was over 3.5 degrees cooler than 1997, at least according to Climate Depot and Watts. I had not heard that one previously

  24. WebHubTelescope says:

    That denier bunch really are charlatans. Lindzen was likely top of the list when it came to a credentialed scientist. Yet we debunked Lindzen’s QBO theory by considering the effect of known lunar forcing that recreate every detail in the QBO behavior. Like I mentioned, he wrote a textbook “Atmospheric Tides: Thermal and Gravitational”, yet could not root out the rather obvious lunar tidal mechanism which forces the QBO behavior. The way things look, Lindzen will never get a chance for a do-over.

  25. Ray, fortunately the global temperature does not exist, so we do not need to look what computational error they made to get the result they wanted.

  26. Brandon Gates says:


    So they agree that “the pause” is a meaningless concept?

    Generally not in the same paragraph.

  27. Andrew dodds says:

    Brandon –

    The first rule of denialism, of any kind, is that no two arguments should be considered together. The denial exclusion principal, if you like.

  28. BBD says:

    Climate sensitivity is low. It’s the sun.


  29. verytallguy says:

    Cool. Friday afternoon denialist exclusion principal bingo. My favourite:

    The Medieval Warm Period was large and global.* Climate sensitivity is low.

    *and was airbrushed out of existence by Mann and the IPCC for the nefarious purpose of imposing socialistic world gubmint, yada yada yada.

  30. Ray says:

    Victor, well of course there’s no such thing as global temperature. I mean how could one even measure that? 😉 Besides, I can’t feel an increase in temperatures with my head buried this far in the sand.

  31. JCH says:

    The Medieval Warm Period was large and global.* Climate sensitivity is low.


  32. Tadaaa says:

    the obvious one I see is all the time

    CO2 is a trace gas – hence can have little effect
    C02 is plant food – hence responsible for all life in the planet

    really good denialist express both points in the same post

  33. The Very Reverend Jebediah Hypotenuse says:

    Climate science is fraught with uncertainties.
    In the future, the Earth’s climate will, a priori, be hunky dory.

  34. dikranmarsupial says:

    (i) CO2 rises in response to increasing temperature not fossil fuel emissions
    (ii) CO2 has been rising, but temperature has not

  35. Joshua says:

    We can’t quantify the externalities of using fossil fuel, but using renewables is far more expensive.

    Appealing to authority is fallacious but allow me to quote Feynman, Dyson, and Crichton to show that I’m right about climate change.

    We can’t trust any of the scientific measures of SATs but we know that there’s been a “pause” in global warming..

    “Skeptics” aren’t kooky enough to doubt the basic physics of the GHE, but even though we’ve been adding aCO2 emissions to the atmosphere, global warming has paused.

    We can’t measure global temperatures and it’s a meaningless concept even if we could, but emitting aCO2 has delayed the next ice age.

    We could get to the problem of this whole climate change thingy if only those alarmist fanatics who lack integrity and promote fraudulent science order to advance their political goals would stop all this name-calling and motive-impugning.

    As a climate scientist, I will testify before Congress and consult with Ted Cruz in order to prevent political activism from corrupting science.

  36. Tadaaa says:

    of course we all know “The Intergovernmental Panel on Climate Change”, established in 1992, is a totally discredited organisation

    of course in the 90’s it was “Global Warming” – now it is Climate Change!!!

  37. rconnor says:

    Past changes in climate, such as the Permian mass extinction events which involved a ~8 deg C rise over ~60,000 years and killed off 96% of all species, demonstrate that the current climate change, which could involve a 4 deg C rise by 2100, is nothing out of the ordinary and won’t be bad. “It’s changed before” is a great argument against mitigation measures.

    Any adjustments to raw data is scientific malpractice, so thank God we have satellite data sets (UAH beta 6.0 more so than UAH v5.6) to tell us the truth.

  38. Willard says:

    You forgot heresies, J, a trope a freedom fighter has independently replicated:

    Pray that climate scientists won’t read Maurice Blanchot to comfort their righteousness.

  39. Brandon Gates says:

    Andrew dodds,

    The denial exclusion principal, if you like.

    So much so that I may steal it. Unfortunately, it has exceptions. Apropos The Very Reverend Jebediah Hypotenuse’s comment above …

    Click to access HHRG-114-SY00-Wstate-ChristyJ-20160202.pdf


    Climate change is a wide-ranging topic with many difficulties. Our basic knowledge about what the climate is doing(i.e. measurements) is plagued by uncertainties. In my testimony today I have given evidence that the bulk atmospheric temperature is measured well-enough to demonstrate that our understanding of how greenhouse gases affect the climate is significantly inadequate to explain the climate since 1979. In particular, the actual change of the fundamental metric of the greenhouse warming signature –the bulk atmospheric temperature where models indicate the most direct evidence for greenhouse warming should lie -is significantly misrepresented by the models. Though no dataset is perfect, the way in which surface datasets have been constructed leaves many unanswered questions, especially for the recent NOAA update which shows more warming than the others. Finally, regulations already enforced or being proposed, such as those from the Paris Agreement, will have virtually no impact on whatever the climate is going to do.

    … Dr. Christy brings us the Certainly Uncertain Monster. Creative guy, he’s even tinkering with Dr. Curry’s wickedly interesting problems while stumping for 5-10% of the US climate budget to fund Team Red:

    I believe policymakers, with the public’s purse, should actively support the assembling all of the information that is vital to addressing this murky and wicked science, since the public will ultimately pay the cost of any legislation alleged to deal with climate.

    When you can’t beat the rent-seekers, join ’em I guess.

  40. Alan Thorpe says:

    The issue is that an average temperature cannot be used in thermodynamics except from the point of view of simplifying a system such as dividing the earth’s system into cubes each with an average temperature. Temperature is an intensive variable which means it does not depend on the size of the system but when dealing with a system which has huge amounts of water as solid, liquid and vapour an average temperature cannot be used to indicate anything because of the latent heat involved. Temperature does not equate with the energy. If any single number is used then it should be changes to the average energy of the earth’s system. Of course it is obvious why this does not happen. Temperature is used to deceive people about the climate because everybody can understand temperature and so they immediately become experts in thermodynamics and fluid flow and climate change. A practical way to illustrate that they don’t know the difference between heat and temperature is to give them the choice of putting their hand in an oven at 200C or a jug of water at 60C.

  41. Alan,
    Your comment started quite well, and then seemed to go off the rails a little. Not quite sure what you’re implying with the end of your comment.

  42. A Thorpe says:

    I’m saying that thermodynamics is about heat not temperature. Temperatures only determine the direction of heat flow, which is always from hot to cold and it is not a net effect as often discussed by climate scientists. This is because they do not seem to understand that radiation is not thermal energy, it is electromagnetic energy and that can travel between objects at any temperature. However, it is only converted into thermal energy when it travels from a hot to a cold body. Physics has a law of conservation of energy, not conservation of temperature, and climate science therefore discusses thermal equilibrium which seems to be that energy in is equal to energy out and they define layers in the atmosphere for the modelling. This is not a valid assumption. Conservation of energy always applies.

  43. Alan,

    Conservation of energy always applies.

    Yes, this is obvious. I’m not sure I’m getting your point, and I have a feeling you don’t fully understand what climate scientists do or what they understand.

  44. dikranmarsupial says:

    “Temperatures only determine the direction of heat flow, which is always from hot to cold and it is not a net effect as often discussed by climate scientists. ”

    No, go back and read Clausius’ book on thermodynamics. At least in the English translation it makes it very clear that there can be a bi-directional flow of heat.

  45. dikranmarsupial says:

    From Max Planck’s book “The Theory of Heat Radiation” (authorized translation by Masius):

    A body A at 100C emits toward a body B at 0C exactly the same amount of radiation as toward an equally large and similarly situated body B’ at 1000C. The fact that the body A is cooled by B and heated by B’ is due entirely to the fact that B is a weaker, B’ a stronger emitter than A.

    [top of page 9]

    Most would regard Planck as a reliable source of information about radiative heat transfer, and it shows that this is not something novel in climate science. Plenty of climate skeptic blogs though don’t seem to understand thermodynamics as well as they think they do.

    Some further examples of the correct understanding of the second law from thermodynamics textbooks can be found in this ScienceOfDoom article.

  46. A Thorpe says:

    Climate scientists are perverting physics to justify their position that humans are causing the climate to change. It is not physics anymore, it is politics.

    The point about conservation of energy is that the law has been changed to a concept of thermal equilibrium which never applies. This assumes energy in = energy out and they claim this applies to the earth as a system. So the energy input from the sun over a year is balanced by the earth’s radiation to space. It is claimed that satellite measurements of both support this. It cannot be true because if it was than the thermal energy of the earth’s system would not change over time and there would be no long term climate change. In the modelling the atmosphere is divided into bands with an assumed net flow of thermal energy across the boundary. Then it is assumed that radiation is thermal energy. It is not. It is electromagnetic energy. Either they know nothing about science or they are deliberately perverting physics to make a case.

  47. Alan,
    Okay, this is getting very silly. I’ll respond to this one, but maybe not to any more.

    So the energy input from the sun over a year is balanced by the earth’s radiation to space. It is claimed that satellite measurements of both support this. It cannot be true because if it was than the thermal energy of the earth’s system would not change over time and there would be no long term climate change.

    In the absence of any external changes (Sun, volcanoes, our emission of GHGs) then we’d expect the system to be – on average – in energy balance (energy in = energy out). Our emissions of GHGs into the atmosphere is pushing the system out of energy balance, which is causing us to warm. We will continue to warm until the retain energy balance. This won’t happen until we’ve stopped emitting GHGs into the atmosphere.

  48. A Thorpe says:

    [Mod: Sorry, I’m not going to be lectured to by someone who should really take their own advice, before providing it to others.]

  49. A Thorpe says:

    [Mod: Sorry, I’m not going to let you post that here. It really is nonsense.]

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