Saturday, January 08, 2005

Global mean temperature 1978-2004



What are your reactions? My reactions are the following:
  • noise
  • 1998 was a pretty warm year

Junkman has also drawn the graph of the surface temperatures here and I guess that you won't be surprised that we may be heating the surface a bit. On the other hand, stratosphere seems to be cooling quite clearly, as NASA's satellite graphs show. I am certainly not claiming that the cooling of the stratosphere proves that the global warming theory is wrong; it does not prove that it is correct either. They usually say that the cooling comes from ozone depletion:

The GHCC people from NASA are, of course, cautious, and they don't use simplified cliches such as that they have proved global cooling. Instead, they say that the answer about the existence of human-induced greenhouse global warming is not clear.

Even if one forgets about the apparent discrepancies of the troposphere temperatures and works with the living-room-like surface data, it is questionable whether the trend goes beyond the historic variability - the hockey stick graph seems to be probably wrong, too. Nevertheless, many people like to claim that there is enough consensus to cripple the world's economy - the main evidence they have is that there exists one human-induced contribution to the global temperature whose sign seems to be positive according to the idealized model - one contribution among hundreds of other and larger contributions that are ignored.

Cooling of the stratosphere

The comments under the article led to various questions - for example, does the troposphere have to warm up if the greenhouse global warming theory is correct? The answer is, of course, "yes". The greenhouse effect means that the troposphere - the lowest layer of the atmosphere where most of "weather" takes place - is absorbing the thermal radiation emitted from Earth's surface via its water vapors and perhaps other greenhouse gases. Therefore it must be heating up if it absorbs more. In fact, according to the global warming models, the warming trend must increase with the distance from the surface.

Of course, it is completely essential for the global warming theory to find a proof that the NASA data mentioned above are incorrect. This is what various people - such as Qiang Fu - argued. Fu argued that one must add a positive contribution to the present temperature of the troposphere in order to agree with the global warming theory, and such an extra contribution may be justified by the cooling of the stratosphere that may be "artificially" lowering our data from the troposphere. In other words, he simply adds a piece of the cooling stratosphere with a significant negative weight, to "improve" the warming of the troposphere.

Roy Spencer from Alabama who is - together with John Christy - the most experienced guy in the satellite temperature measurements claimed that the paper by Fu was rubbish and that it did not appreciate some exact methods and insights that the Alabama guys made decades ago. Qiang Fu then published another paper in Nature defending himself at the end of 2004, while some other papers attacked his work - and the Saga continues. I am not capable to make unique conclusions who of them is right and how much - that would be just guessing based on the fact that Roy Spencer just looks much brighter to me - but I hope that it is enough to see that as of the end of 2004, the question whether the troposphere is warming enough to agree with the global warming theory is open.

Incidentally, Roy spencer also wrote about the green reaction to the tsunami here. He also explains why the current climate models are not trustworthy here.


  1. Wow. I thought the GW theory was much better off...

    saludos desde M'exico :D

  3. Lubos,

    at the junkscience link there are actually two
    charts. The first (which you posted) shows no trend
    but the second seems to show a trend from 1978 to 2004.
    Do you know why they are different?
    It seems they are recorded by different teams/methodes ?

    Thank you,
    Wolfgang Beirl

  4. Hi Wolfgang, sure. I thought that my short text explained it. The second graph that goes up is GISTEMP, which is (NASA) Giss SURFACE temperature. It's being directly heated by the civilization effects. The noise conostant graph is troposphere - which is the lowest portion of the atmosphere with clouds and greenhouse gases. I've also included a NASA link to stratosphere - which is above troposphere. Stratosphere is cooling quite clearly.

    I think that these numbers and graphs are pretty transparent and clear, they show that there is no warming of the atmosphere going on, and I don't understand why someone is ready to listen to vague and politicized statements instead of just evaluating very simple and unambiguous graphs that show quite clearly what's warming and what's not.

  5. Lubos,

    thank you for clarifying this (I guess I am a bit slow today,
    but to be fair you mention it only in a half-sentence).
    So the surface is warming, the troposphere is essentlially flat
    and the stratosphere is cooling.
    Is this really inconsistent with a greenhouse effect ?

    Thank you,
    Wolfgang Beirl

  6. Wolfgang, you seem to be a bit confused, and a part of it may be my fault.

    There can be nothing inconsistent with the greenhouse effect. The greenhouse effect is a demonstrable, obviously existing effect that has been necessary to keep Earth from complete cooling. Most of it - some people say 98% - come from water vapor in the troposphere - and there are probably several other gases that can give you minor corrections.

    The open question is not whether the greenhouse effect exists. The open question is whether it was becoming stronger, and whether the human activity and its CO2 has a significant impact.

    And sure, the people who believe the conjecture that we are warming Earth by significant, additional new greenhouse effect also believe that the troposphere must be warming as well and the data from NASA must be incorrect. They will always tell you that the satellite measurements must be wrong. You know, it's a religious system where data don't mean much.

    Wolfgang, this is kind of a basic definition of the greenhouse effect: it's the effect of troposphere (the lowest portion) ABSORBING the thermal radiation emitted from Earth's surface - radiation that would otherwise escape. So of course that the very basic prediction of a stronger greenhouse effect is an INCREASING temperature of the troposphere. Clear?

  7. Lubos,

    I do not know much about this and I certainly do not
    want to consume too much of your time with my questions.

    I just thought that the troposphere absorbing more of the
    radiation (which would otherwise escape through the
    stratosphere) due to increased greenhouse gases, could
    explain why the stratosphere is cooling.

    Thank you for your time,

  8. Dear Wolfgang, stratosphere is cooling because of various things including ozone depletion, and you could argue in the way you do.

    But what is not questionable is that if the greenhouse effect is strengthening, then the troposphere must be warming. Troposphere is the sphere that is responsible for nearly everything about weather, and it is the layer that absorbs the thermal radiation emitted by Earth's surface via the greenhouse gases (mainly water, also CO2, methane etc.). If it absorbs, it must get warmer.

    Either the hypothesis about increasing greenhouse effect is wrong, or NASA's graphs about troposphere must be wrong. Of course that some people have argued that they should be wrong - e.g. Qiang Fu et al.

  9. I was present when the NRC panel reported its results at the 97 AMS meeting in Long Beach, and questioned the panel members about the results. They were very clear about the following: a) The satellite measured tropospheric average showed at most only a very small warming, b) measured land surface temperatures showed a clear and statistically significant warming both before and after the satellite era, c) they were not about to be drawn into speculation about the causes of the warming trend. (For some reason, I can no loger see the junkman's surface plot, which showed a pretty clear warming trend.

    It seems a bit counterintuitive that the tropospheric average should stay constant while the surface warms, and this fact was the basis of critiques by S. Fred Singer and others. Some, at least, of the models reproduce this behavior though, and if I recall correctly, there may be a link to the fact that most of the observed warming takes place at night.

    The following link from the same NASA site cited by Lumo shows the full complexity of at atmospheric response, with warming at the surface and alternating layers of cooling, warming, and cooling above.

    But the surface is clearly warming, and mostly we and our plants and animals live on the surface, so that's probably the most salient fact for environmental effects on humans.

    I think Lubos, that you would like us to believe that the clear stratospheric cooling trend somehow weakens the case for global warming. That is not necessarily the case, as the following simple (but likely wrong, at least in detail) model shows. More heat retained at the surface means less transported to the stratosphere and hence a cooler stratosphere.

  10. Lubos,

    I found a link at LLNL about the
    troposhere/tropopause/stratosphere layer system,
    which is quite interesting and may add to the
    discussion here.

    A fascinating topic actually,
    Wolfgang Beirl

  11. LOL You *must* be an MIT student, yes? :)

    I used to live in Boston. Love the city! Thanks for stopping by on my blog. Sadly, no, that is not me.


    Propaganda and insults, not science. The fact that the troposphere does not seem to be warming is accepted by virtually all climate scientists, as is the fact that the surface is warming.

    Contrary to your assertion, the fact that most of the greenhouse absorption takes place in the troposphere does not necessarily imply that the troposphere gets warmer. The effect of the greenhouse gases is to increase the mid to long IR opacity of the atmosphere. This makes them better absorbers and better radiators, as you well know. The additional radiation they absorb is upwelling radiation from the Earth - the additional radiation they emit goes partly to space and partly back to the Earth. The story is more complex than that of course, but you should be able to see the idea.

  13. No, capitalist, you seem to be very ignorant about absolutely basic issues.

    Every proponent as well as opponent of the global warming hypothesis will tell you that the troposphere temperature must be evolving in almost exactly the same way as the surface temperature if the increasing greenhouse effect explanation is correct. This is implied by all the models that they use.

    See e.g. the link that I've referred to in my article (this is a "pro-global-warming" article!) quote:

    "The UAH team studied satellite data and found the troposphere, which extends up to an altitude of about 7.5 miles - and where most of the planet's weather occurs - was not warming as fast as the surface."

    "This finding conflicted with climate models, which predicted the two should be warming at more or less the same rate. The discrepancy dealt a potentially serious blow to the contention that Earth's climate is experiencing a warming that is greater than historic variation."

  14. Here is a comment on the coexistence of surface warming and tropospheric cooling. Note that the authors are John Wallace (the chaiman of the NRC panel I cited) and John Christy (a member of that panel) whom you cited above.

    excerpts: ...Wallace and Christy conclude, "Despite differences in the two sets of temperature data, the Earth’s surface is in fact warming. ..

    The lead author is Dian Gaffen of the Air Resources Laboratory, NOAA, and is co-authored by John Christy of Earth System Science Laboratory, University of Alabama-Huntsville, among others. Gaffen et al. offers possible explanations of the temperature discrepancy, such as "Surface and lower tropospheric temperatures may respond differently to changes in a suite of natural and human-induced climate forcings, including well-mixed greenhouse gases, stratospheric and tropospheric ozone, tropospheric aerosols, and stratospheric volcanic aerosols."The discrepancy is largest at the tropical belt and so the paper focuses on the temperature trends for those areas. Balloon measurements of the tropical belt began in 1960 and show that the lower to mid troposphere actually warmed faster than the surface in "a pattern consistent with model projections of the vertical structure of tropospheric warming associated with increasing concentrations of well-mixed atmospheric greenhouse gases. From 1979 to 1997, however, the balloon data "show the same pattern of surface warming and tropospheric cooling since 1979 as the independent surface and MSU (satellite) observations."That said, the problem of unravelling temperature signals is nontrivial, since each satellite temperature measurement is a weighted average of all temperatures along the path from satellite to ground. Much better measurements should be available when the NPOESS (satellite system) with the CMIS (conical scanning microwave and infrared sounder) flies in a few years.

  15. I agree, this confirms my point. This blah blah blah story may be simplified by saying that we still don't understand the dynamics and forces driving the temperatures at various altitudes. It's what I also argued - the explanation could be different and contradicting the "conventional" global warming models.

    John Wallace's viewpoint on this question is, of course, identical:

    http..."Wallace went on to say that the disparity between the temperature trends at the surface and those in the lower atmosphere (Figure 2) points to a weakness in scientists' ability to predict future warming."

    You might have wanted to support the GW theory, but the result of your comment is definitely just the opposite. Even a priori, using Wallace and Christy to support the statements that we know that GW will take place is not the best possible idea! ;-)

  16. CIP,

    I agree with Lubos, the main ingredient of the
    GW hypothesis (warming of the troposphere) is
    not very well supported by the available evidence.
    The link you provided does not explain much, except
    stating the obvious that this is a complicated issue.

    Unfortunately, the scientific questions about atmospheric
    and climate physics are difficult enough, the political
    aspects do not make it easier.

    But fortunately it seems that the GW effect (if it exists)
    is weak enough that we have probably enough time to study
    it better 8-)

    Best regards,
    Wolfgang Beirl

  17. I think I've said before that I remain slightly agnostic on the cause of the global warming. Cristy, Wallace, and even the Junkman's graph show that global warming (at the surface) has been happening. It's not impossible that the correlation between antropogenic CO2 increase and the warming is accidental. My guess, though, is that it isn't.

  18. Pages at the site linked from the blog make it clear that as of 1997, none of the climate models handled convection very well. Has anything changed in the 7 years since?

  19. Hi anon!

    People certainly tried to struggle with this topic. If you open e.g.,

    you will see that these Radiative-Convective Models have some advantages as well as disadvantages - they need new parameters. They still represent the horizontal surface of the Earth by one point. (I was not sure whether the page was just kidding, but it certainly does not look like a convincing model if the surface of Earth is represented by one point.)

    The text is written in such a way that my feeling is that these models are not those that are actually used for anything, and they may still work with the "zero-dimensional models". It does not look too realistic if they reduce so many dimensions - all eleven, in fact. ;-)

  20. Hey Lubos,

    Check out:

    This is a review in Scientific American Magazine of Lomborg's book "The Skeptical Environmentalist." The book review presents some arguments about environmental science that you might find interesting.

  21. Hi, Lubos!

    Are you going to update this post now that the observations have been updated, like any good scientist would? Just asking.

  22. Ok...perhaps we need to discuss what temperature is - it is a measure of thermal energy. However, it is not the only measure.

    A 10 lb. lump of lead at 32 degrees farenheight has a specific amount of thermal energy. A 20 lb. lump of lead at the same temperature actually has twice the amount of thermal energy.

    The reason I bring this up is that if the troposphere really is expanding, as suggested by one of the articles posted here - its temperature could remain constant while increasing it's level of thermal energy.

    It would not appear to be "warming" even though its thermal energy would be increasing.

    Just a thought....

  23. Here is a plot of MSU data from 1978-June 2009. Just copy and paste into your browser

  24. Here is a plot of MSU data from 1978 thru June 2009