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The wisdom of Solomon

Filed under: — gavin @ 29 January 2010

A quick post for commentary on the new Solomon et al paper in Science express. We’ll try and get around to discussing this over the weekend, but in the meantime I’ve moved some comments over. There is some commentary on this at DotEarth, and some media reports on the story – some good, some not so good. It seems like a topic that is ripe for confusion, and so here are a few quick clarifications that are worth making.

First of all, this is a paper about internal variability of the climate system in the last decade, not on additional factors that drive climate. Second, this is a discussion about stratospheric water vapour (10 to 15 km above the surface), not water vapour in general. Stratospheric water vapour comes from two sources – the uplift of tropospheric water through the very cold tropical tropopause (both as vapour and as condensate), and the oxidation of methane in the upper stratosphere (CH4+2O2 –> CO2 + 2H2O NB: this is just a schematic, the actual chemical pathways are more complicated). There isn’t very much of it (between 3 and 6 ppmv), and so small changes (~0.5 ppmv) are noticeable.

The decreases seen in this study are in the lower stratosphere and are likely dominated by a change in the flux of water through the tropopause. A change in stratospheric water vapour because of the increase in methane over the industrial period would be a forcing of the climate (and is one of the indirect effects of methane we discussed last year), but a change in the tropopause flux is a response to other factors in the climate system. These might include El Nino/La Nina events, increases in Asian aerosols, or solar impacts on near-tropopause ozone – but this is not addressed in the paper and will take a little more work to figure out.

Update: This last paragraph was probably not as clear as it should be. If the lower stratospheric water vapour (LSWV) is relaxing back to some norm after the 1997/1998 El Nino, then what we are seeing would be internal variability in the system which might have some implications for feedbacks to increasing GHGs, and my estimate of that would be that this would be an amplifying feedback (warmer SSTs leading to more LSWV). If we are seeing changes to the tropopause temperatures as an indirect impact from increased Asian aerosol emissions or solar-driven ozone changes, then this might be better thought of as impacting the efficacy of those forcings rather than implying some sensitivity change.

The study includes an estimate of the effect of the observed stratospheric water decadal decrease by calculating the radiation flux with and without the change, and comparing this to the increase in CO2 forcing over the same period. This implicitly assumes that the change can be regarded as a forcing. However, whether that is an appropriate calculation or not needs some careful consideration. Finally, no-one has yet looked at whether climate models (which have plenty of decadal variability too) have phenomena that resemble these observations that might provide some insight into the causes.

487 Responses to “The wisdom of Solomon”

  1. 1
    Steve says:

    A little bit out of topic, a new paper by Susan Solomon:

    Contributions of Stratospheric Water Vapor to Decadal Changes in the Rate of Global Warming

    Is this significant?

  2. 2
    Paul Briscoe says:


    I have been reading your articles with interest for quite some time. I must congratulate you on your “real science” approach to AGW and climate change.

    I am posting now because I understand that Susan Solomon of the NOAA has just published a paper in Science showing that water vapour levels in the stratosphere have fallen by around 10% since 2000. Apparently, when this was fed into climate models, it was found that it could have reduced greenhouse warming by up to 25% in the past decade.

    I stress that I have not personally seen the paper, but I would certainly be interested to know your take on this.

    Kind regards,


  3. 3
    Tim Jones says:

    Is this the missing link?

    Global Warming Slowed by Decline in Atmospheric Water Vapor
    From: Sid Perkins, Science News
    Published January 29, 2010

    “A sudden and unexplained drop in the amount of water vapor present high in the atmosphere almost a decade ago has substantially slowed the rate of warming at Earth’s surface in recent years, scientists say.

    “In late 2000 and early 2001, concentrations of water vapor in a narrow slice of the lower stratosphere dropped by 0.5 parts per million, or about 10 percent, and have remained relatively stable since then.

    “Because the decline was noted by several types of instruments, including some on satellites and others lofted on balloons, the sharp decrease is presumed to be real, says Karen Rosenlof, a meteorologist at NOAA’s Earth System Research Laboratory in Boulder, Colo. 

    “And because water vapor is a powerful greenhouse gas, the decline has slowed the increase of global temperatures, Rosenlof, Susan Solomon, also of NOAA in Boulder, and their colleagues report online January 28 and in an upcoming Science.

    “This is such a sudden decrease, we can’t explain what’s behind it,” Rosenlof says. One large source of water vapor in the stratosphere is the oxidation of methane, she notes. But the decline in concentration of that gas detected by the researchers seems to be limited to a layer 2 kilometers thick in the lower stratosphere, while methane is found throughout the stratosphere. And even though scientists have discerned a leveling off in atmospheric methane in recent years, that trend doesn’t seem to be directly linked to the drop in the concentrations of stratospheric water vapor, she says.


  4. 4

    Could this have anything to do with the recent rise in water vapour?…/Chris

    Climate Change: The Next Generation
    Yesterday, January 16, 2010, 10:36:15 AM
    Arctic permafrost leaking methane at record levels — methane emissions from the Arctic have risen by 31% in just 5 years

  5. 5
    Eli Rabett says:

    The Hungarian is coming!! The Hungarian is coming.

  6. 6
    Sou says:

    Thank you for this post, the paper is, or more accurately the various media portrayals of the paper are receiving a lot of attention. The voice of some skeptics tends to overwhelm common sense and perspective.

    If I understand the last paragraph, you are suggesting changes in stratospheric H20 are quite possibly a feedback effect maybe involving methane (which may in turn involve CO2 and temperature, not just human emissions of methane).

    I look forward to further findings as the research continues.

  7. 7
    Doug Bostrom says:

    I was delighted to hear of this paper. Recently we’ve seen frustration with inadequate explanations of variability highlighted in the popular press, actually exploited for political purposes. Here’s a significant amount of that mystery explained.

    Scientific progress trundles on, eventually trumping obfuscation. Hooray!

    NPR did an pretty complete item on this yesterday on ATC. Fully contextualized, could not really ask for better.

  8. 8
    Craig Allen says:

    If this phenomonon is real, then I guess it provides a good opportunity for testing and improving climate models. If they already exhibit it, then well and good. If not, then finding out will presumably lead to improvements to the models.

    Which leads me to wonder, what are the other key phenomona that emerge in climate models? It would be interesting to see a list and to see a tally of which models exhibit which phenomonon and how well they do it. I imagine that investigating this is a key aspect of building and improving models.

  9. 9
    Prasad Kasibhatla says:

    Re the contribution of the post-2000 decrease in stratospheric water vapor contributing to the ‘flattening’ of the global warming trend – I am struck by the dissimilarity between the observed and modeled temperature curves post-2000 in Figure 3b. It looks like the model’s response it to simply adjust (almost instantaneously) to the drop in water vapor in 2001, and I see no evidence of a ‘flattening’ of the trend. Am I missing something?

  10. 10
    Jimbo says:

    OT but very important to the theory of AGW. Can you commmenters give me feedback (pun intended) on the following recent headlines generated by Nature magazine that state that CO2 amplification is less than we thought:

    Nature: December 2009
    “Ensemble reconstruction constraints on the global carbon cycle sensitivity to climate”

    “Temperature and CO2 feedback ‘weaker than thought'”

    “Amplification of Global Warming by Carbon-Cycle Feedback Significantly Less Than Thought, Study Suggests”

  11. 11
    Tim Jones says:

    Anti-science propagandist DOUG L. HOFFMAN is already twisting the stratospheric water vapor finding to mean that water vapor has been driving temperatures all along.

    “A new report in Science underscores what many scientists have been saying for years, it’s water vapor, not CO2, that has been driving global temperature changes in recent decades.”

    When Susan Soloman wrote in:
    “………. depressed global warming by about 25% compared to that which would have occurred due only to carbon dioxide and other greenhouse gases.”

    Hoffman asserted that the author is a liar.

    “- Anything to maintain the lie that CO2 causes warming.”

    Isn’t it an amazing coincidence that this stuff appears on the web just as big coal tries to sabotage climate change legislation?


    This paper may have some bearing on the matter:
    The annual cycle of stratospheric water vapor in a general circulation model

  12. 12
    Tim Jones says:

    Re: 660 Richard Steckis says:
    27 January 2010

    “CO2 is NOT an oxidative byproduct of methane oxidation.”

    “[Methane] is short lived in the atmosphere (5-15 years)
    and it’s oxidation byproducts are water vapour and CH3.”

    “the CH3 is further oxidised to CH3O2 which reacts with the
    peroxy radical HO2 to produce methyl hydroperoxide and
    “The hydroperoxide is then precipitated out of the atmosphere
    in rainfall.”

    I’m not familiar with this chemistry. CO2 _is_ an oxidative
    byproduct of CH4, right?

  13. 13
    Tilo Reber says:

    Chris: #4
    “Arctic permafrost leaking methane at record levels — methane emissions from the Arctic have risen by 31% in just 5 years”

    If I’m reading things right, Chris, this would tend to increase the amount of H20 in the stratosphere, rather than decrease it – which is what this study found to have happened around 2000.

  14. 14
    Tilo Reber says:

    The suggestion seems to be that it is a drop in the cold point temperature that allowed less water vapor to make it through to the stratosphere. But there doesn’t seem to be an explanation of why there would be lower cold point temperatures when the SSTs in the tropics are warmer.

    Another discussion is here:

  15. 15
    Edward Greisch says:

    “Science” only shows an abstract. I don’t have a subscription. I see that you say that the answers to my questions “will take a little more work to figure out.”
    I will be watching RealClimate for those answers because there is plenty to be puzzled about on this subject. I expect that the denialists are already making a big deal out of this.

  16. 16
    ScaredAmoeba says:

    Off topic, new paper about the implications and reliability of the new paper:

    ‘A new estimate of the feedback between temperature and atmospheric carbon dioxide (CO2) concentration has been derived from a comprehensive comparison of temperature and CO2 records spanning the past millennium.’
    claims that the amplification of current global warming by carbon-cycle feedback will be significantly less than recent work has suggested.

    David C. Frank, Jan Esper, Christoph C. Raible, Ulf Büntgen, Valerie Trouet, Benjamin Stocker, & Fortunat Joos. Ensemble reconstruction constraints on the global carbon cycle sensitivity to climate. Nature, 2010; 463 (7280): 527 DOI: 10.1038/nature08769

  17. 17

    “CH4+4O2 –> CO2 + 2H2O). There isn’t very much of it (between 3 and 6 ppmv), and so small changes (~0.5 ppmv) are noticeable.”

    Your oxidation equation is wrong. It doesn’t even balance. What happened to 4 oxygen atoms? Did they just dissapear? The oxydation equation for methane in the atmosphere is:

    CH4 + OH -> CH3 + H20

    CH3 is oxidised by:

    CH3 + O2 + M -> CH3O2 + M

    CH3O2 + H20 -> CH3OOH + O2

    The methyl hydroperoxide is precipitated out of the atmosphere with rainfall. CO2 is NOT an oxidative byproduct of the atmospheric oxidation of methane.

    Source: Wayne, R.P. (1992). Chemistry of Atmospheres. 447pp.

    [Response: This is your third post making the same point. Thanks for the attention to my oxygens (fixed above), but you are not looking at the right pathways. In the stratosphere you have reactions with OH, O(1D), atomic O, and Cl which are very complicated, and I think you’ll find there is no rainfall in the stratosphere to remove any soluble products. Table 1 in Saueressig et al (2001) gives an overview. Also see Ridal et al (2001; 2002) – gavin]

  18. 18
    Gilles says:

    I’m puzzled. I thought that there was NO statistically significant change in Global warming, and that basically models were ALREADY able to explain everything by solar variations, volcanic aerosols and anthropic forcings. Did I miss something important in the IPCC reports ?

  19. 19
    Gilles says:

    Craig : If this phenomonon is real, then I guess it provides a good opportunity for testing and improving climate models. If they already exhibit it, then well and good. If not, then finding out will presumably lead to improvements to the models.

    Which leads me to wonder, what are the other key phenomona that emerge in climate models? It would be interesting to see a list and to see a tally of which models exhibit which phenomonon and how well they do it. I imagine that investigating this is a key aspect of building and improving models.

    Improving models? but I thought that this was all “settled” ! and I thought the slowing of warming rate since 2000 was imaginary and just claimed by some idiot denialists who don’t understand what a linear regression is ?

    seriously : a model is a model. Meaning : no human being has the knowledge to put “everything” in a computation and just “reproduce reality”. And no human being has the power to “list ” what he doesn’t know.
    A model is always an oversimplification of reality. We HOPE catching the essentials of this reality, but we can’t never be sure. Nothing is ever “settled”. And the proof that we have catched the essential of reality is NOT in the fact that we can reproduce known data , because many wrong models can too. Reproducing data is not a very strong test of validity, I am sorry to have to remind it. The very strong test is PREDICTIVE POWER. I still wait for a validation of climate models by non-trivial (meaning not just a vague extrapolation of current trends within 2 or 3 sigmas) predictions.

  20. 20

    You will also notice from the equations for the oxidation of methane that the water vapour produced is later consumed in the conversion of CH3O2 to methyl hydroperoxide. Therefore there is a net zero production of water vapour by the full oxidation of methane to the peroxide product that is precipitated out of the atmosphere. Oxygen is the final byproduct of atmospheric methane oxidation that stays in the atmosphere.

    [Response: Now this is seriously wrong. There is no oxygen in methane, and so the creation of oxygen as a final byproduct is impossible. There is no precipitation in the stratosphere (except for a tiny amount of of PSC formation). – gavin]

  21. 21

    Your equation should read:

    CH4 + 2O2 -> CO2 + 2H20

    That equation is the oxidation equation for the COMBUSTION of methane. i.e. You need the application of heat for the equation to progress. It is not the equation for the atmospheric oxidation of methane.

    [Response: thanks. The O’s now add up. But this is representative of the net effect – whether the reaction is actually via OH, or O(1D) or atomic O or Cl – and the point that CH4 produces H2O is clear. – gavin]

  22. 22
    Tony O'Brien says:

    More puzzles.

    One wonders what is ahead if the hottest decade ever was cooled by a drop in stratospheric water vapour.

  23. 23
  24. 24
    Pekka Kostamo says:

    A couple of comments.

    There is a reference to balloon borne radiosonde data. I consider these data to be quite unreliable in the stratosphere. The sensors have slow time constants (minutes) at tropopause temperatures. An sensor improvement in this respect would show up as lower humidity just above the tropopause (where the humidity abruptly drops to the typical stratospheric 2 %RH value).

    Besides, the sensors are subject to partial or total icing whenever the probe traverses a liquid water cloud during its ascent. Liquid water in clouds does occur naturally down to about -38 degC. Some of the data becomes obviously wrong and is rejected, other readings are just unreliable. Improvements is this respect have also been made over the years, resulting in lower humidity readings in the stratosphere. I believe some new (improved) instrument types were introduced extensively into the network over the past 10 years. Removing old biases is not always a good thing.

    I do not trust radiosonde sensor calibrations, either, at the extremely cold and low humidity conditions. It is not a trivial operational matter.

    Like in almost all routine weather observations, the requirement driving the performance development has not been global climate science needs.

    Satellite measurements could be more reliable.

    As to humidity transport through the tropopause, there are several possible ways. I interviewed a number of meteorologists back in the 1970’s, trying to understand what would be reasonable in observation data provided by some new sensors.

    Insertion of humidity into stratosphere by strong convection events was stated as certain but rare by a tropical forecaster. A more speculative comment from another source was about possible horizontal (tunneling) transport via channels formed by double tropopauses, rather common at 30’s latitudes. Yet another idea was insertion i.e. in Greenland, where the tropopause effectively hits the ground at times in winter season. (How about high mountain ranges?) There are also infrequent (3 – 5 times per year) tropopause folding events associated with strong fronts, bringing stratospheric air down and thus resulting in extremely low humidity layers close to the ground. (Evidence is radioactive dust found in those layers, normally circulating near the tropopause). This is observed in sounding profiles just about everywhere. The folding events might disturb the tropopause locally and cause transport of humidity into the stratosphere.

    My conclusions were that the stratospheric humidity is not constant enough to serve as a reference point in measurements. The extremely low (1 – 10 %RH) readings close to the ground are real. Good enough for my purposes, then.

    In my opinion, there is an issue about the variability of water vapor. In the long term relative humidity probably remains constant even when warming occurs, so water vapour is a positive temperature feedback. Short term change is another matter and a likely factor in the unforced variability.

    Incidentally, a new observation technology has emerged over the past 15 years. Lower atmosphere refractivity (strongly dependent on humidity) has been routinely measured for some time already based on satellite-to-satellite radio signal transit time. It also is another independent method of temperature profiling.

  25. 25
    JohnRS says:

    So here’s yet another paper telling us something we didnt know before about the climate system. As I understand it we still have very limited understanding of the action of water vapour in the atmosphere (as this new work shows) and basically have a complete inability to model clouds in any credible way. And yet “Climate Scientists” still think their 50-100 year predictions are credible and should be used as the basis for multi-trillion dollar decisions with impacts out to 2100 and beyond, when articles like this one illustrate they dont even know what’s happening on a decadal time frame?

    [Response: Your logic is severely strained. There are many things we don’t know about the climate system. Why that makes you happier about the giant geophysical experiment we are undertaking is unclear. Secondly, there are no clouds in the stratosphere (except a few PSC in the winter polar vortex) . And third, there are many processes that have predictable effects on the climate despite the uncertainties – the seasonal cycle for instance is still predictable even if weather forecasts can’t go beyond a few days, volcanoes have predictable affects on interannual variability even if we can’t predict El Niño etc. – gavin]

  26. 26
    Peter Coates says:

    This sounds almost encouraging: It seems to a lay person that all the feedbacks so far seem to be positive. This sounds like there might actually be a significant negative feedback loop in the system too. And I was thinking that atmospheric methane was unmitigated bad. Is Gaia more forgiving than we give credit for?
    It is certainly all far more complicated than most people realize, and not the sort of system to muck with lightly.

  27. 27
    KLR says:

    Do changes in the Earth’s orbital eccentricity have any effect on terrestrial volcanism? Just a stray notion I had, no doubt it’s been entertained plenty of times in the past. Perhaps multiple volcanic outburts in a short period of time would help to bring an end to an interglacial, in concert with the other Milankovitch cycles.

  28. 28
    Icarus says:

    Does this paper help towards a better understanding of how much of the variability in our global mean temperature measurements is down to genuine changes in the Earth’s energy balance, and how much is just down to inadequacies in our knowledge of how energy is moving around the climate system? It seems to me that it’s very important for us to be able to tell whether, for example, an apparent reduction in the rate of global warming is due to factors such as heat being sequestered in the deep ocean where we can’t measure it so well (which presumably wouldn’t affect the total energy of the climate system) or whether it’s due to things like a reduced greenhouse effect from stratospheric water vapour (which presumably would do).

  29. 29

    The oxidation pathway for methane is slightly different in the stratosphere. That pathway is shown in Fig. 1. of:

    Rockmann et. al. Atmos. Chem. Phys., 3, 2015–2023, 2003

    PDF can be found at:

    That pathway does produce a net increase in water vapour but does not produce any CO2.

    [Response: The reaction above is overly simplistic (there are a number of pathways to oxidise CH4), but they all end up with water and CO2 (both CO and HCO are both oxidised in turn). – gavin]

  30. 30
    Mike Ern says:

    Curious, is there a way to calculate what a decrease in stratospheric vapor (from the current level down to zero) would have on temperature if we assume the level is related to the shift in global patterns of sea-surface temperatures which influence evaporation and vapor movement?

  31. 31
    Ed Davies says:

    What is the contribution from jet exhausts to the stratospheric water vapour content?

    [Response: Negligible. The majority of jet flights don’t get into the stratosphere – most fly in the upper troposphere. However their water vapour contributions do add slightly to their climatic impact. – gavin]

  32. 32
    Ray Ladbury says:

    The Nature article provides only a very weak constraint on carbon-cycle feedback (very large error bars). The favored value is at the low end of expectations, but 1)it’s one study, 2)I don’t have access to Nature here at home 3)it doesn’t preclude higher values with any sensitivity, and 4)it doesn’t change the overall estimates of climate sensitivity, which are strongly constrained to be around 3 degrees per doubling.

  33. 33
    Ed Davies says:

    Partially answering my own question with some very approximate back-of-the-envelope numbers: total water vapour content of the bottom 10 km of the stratosphere: 7.5e12 kg and total water emissions from jet exhaust: 75e9 kg/year. So, may be significant depending on the residence time.

  34. 34
    Ani says:

    Another excellent topic to discuss put out by RS. As a layman tech who very seldom posts here, I mainly do it for one of my grandaughters, a ten year old that is the intelligent one, other than the fact she thinks I walk on water. I just want her to know that if she has a question and she can ask an expert she should do so. I chuckled when I read you will try to get to it over the weekend. Nice to see NASA hasent changed since I worked for them other than you know what a weekend is. Since a Phd at GS15 makes so much I hope your book does well.

  35. 35
    MR SH says:

    I am interested in the mechanism of this phenomena, especially the relationship to the external variability, such as solar activities, or a part of natural feedback. Anyhow this new finding must improve the climate model dynamics.

    What is strange is, why the skeptics neglect the remaining 75% of the radiative force which is well explained by the AGW theory.

  36. 36

    Most models simply estimate changes in watervapoe fron changes in SST.

    But ww have built 45,000 dams in the last 50 yrs, and those reservoirs add more.DITTO irrigation.

    Then there are changes in path length between evaporation and precip.

    This comes to you from the stratosphere at
    10km, enroute SEA-ATL.

  37. 37
    captdallas2 says:

    As an impoverished fishing guide I can’t afford to view the full text. With that explanation to avoid ridicule for my ignorance, what drives the change in strat h20? Arctic methane release does not seem to be the cause because 1998 through 2007 was pretty warm up north.

    If anyone has a link to the full text that I can access gratis I would love to read it.

  38. 38
    Hank Roberts says:

    A decade ago some astronomers were talking about seeing traces of small ice/frost comets depositing water in the upper atmosphere. Anything since, anyone know?
    (which may be a long dead site, it’s certainly been a long time since update)

  39. 39
    Ani says:

    Ok just an observation, and I don’t have any idea if physics would support this, my research is whatever I can do with my blackberry. It looks to me, a picture type of guy, that we could be compressing the atmosphere below the trop. To me this would do things like intensify the jetstream and give north America a polar outbreak that’s out of synch with the solar cycle. Now there would be a myriad of things we would have to look at like surface pressure trop height and pressure etc. I guess its a good thing that mother earth is putting a cap on the thunderstorms and also letting us keep our atmosphere. If this sounds silly please forgive as I like most hate to look foolish.

  40. 40
    Anand says:

    Ray Ladbury says:
    The Nature article provides only a very weak constraint on carbon-cycle feedback (very large error bars).
    The favored value is at the low end of expectations, but
    1)it’s one study,
    2)I don’t have access to Nature here at home
    3)it doesn’t preclude higher values with any sensitivity,

    Your “it’s one study” ‘excuse’ is quite lame and more importantly it backfires. The paper’s just been published it has already entered the “it’s one study” category. Isn’t that a compliment?

    “3) It doesn’t preclude higher values with any sensitivity”.
    Read between the lines, man – the way the authors put a non-sequitur like:

    “Although uncertainties do not at present allow exclusion of y (gamma) calculated from any of ten coupled carbon-climate models…”

    to buy ‘street-cred’ for their contentions is hilarious. No one can exclude any of the present models – isn’t that fact?

    Moreover the authors complete the same sentence to say:

    “Although uncertainties do not at present allow exclusion of y (gamma) calculated from any of ten coupled carbon-climate models, we find that y (gamma) is about twice as likely to fall in the lowermost than in the uppermost quartile of their range.”

    Meaning – the authors make concessions to existing uncertainties in a statement that offers actual number limits to ‘y’. The exact opposite of what you are implying.

    Read the paper – it has more surprises in store. Nature itself put a better spin on the paper, from a warmist perspective, that is.

    Just had to step in to call out this severely homework-constrained post.

    I guess I’ll put in the disclaimers myself: Delete if required. Void where prohibited.


  41. 41
    Ray Ladbury says:

    “Street cred…”? Good lord, have you ever even read a scientific paper before? Did you look to see how large the error bars are on their results?

    In science, you never, ever place high confidence in a single result based on a single study of a single line of evidence. That is why CO2 sensitivity estimates are based on over a hundred studies of about a dozen different lines of evidence. That is the difference between science and anti-science. Understand?

  42. 42
  43. 43

    The volume of tropical stratosphere that Solomon et al. reexamine in their current Science paper, is the upper part of the same more or less continuous global volume usually referred to as the tropical upper troposphere, where radiosonde measurements and GCM models SEEM (keep reservations in 24, above, by Pekka Kostamo, in mind) to disagree about the extent of warming (measurements less than model ‘predictions’ by about 0.5ºC).

    [See famous Fig. 9.1, p. 675, Chapter 9 of “Understanding and Attributing Climate Change” Hegerl et al.(2007) In: Climate Change: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. and

    see Fig.1, Douglass et al. (2008) “A comparison of tropical temperature trends with model predictions” Int. J. Climatol. 28: 1693–1701.]

    Although the associated uncertainties in no way challenge the arguments that increasing greenhouse gases produce increasing global temperatures, the resolution of these ‘discrepancies’ about ‘what is forcing what’ could reduce the GCM-predicted trend in global mean surface temperature from about 0.2ºC to about 0.15ºC per decade.

    Gavin: Please comment.

  44. 44
    yourmommycalled says:

    I not sure where Pekka Kostamo (#24) got that the time constant of radiosondes are on the order of minutes, because it is no where near close to being correct. I buy hundreds of Vaisala RS92-SGP’s a year. The manufacturer’s specification for the temperature time constant is less than 1 second at 100 mb. The relative humidity sensor has 0.5 second (6m/s flow, 1000mb, 20 C) time constant. The longest lag in measurement due to improper or poor conditions at launch is 13 seconds. This information is from the manufacturer, NCAR and NSSL and my own personal experience both on a daily basis and during numerous field campaigns dating back to 1979.

    Strange that all of that new and wonderful instrumentation you talk about are indirect measurements calibrated against the direct measurements made by the radiosondes. Yet another case of somebody pulling monkeys out of the netherworld

  45. 45
    Completely Fed Up says:

    “18 Gilles says:
    30 January 2010 at 2:39 AM

    I’m puzzled. I thought that there was NO statistically significant change in Global warming”

    No, you’re not puzzled. You’re squishing in your pants and kidding on you’re puzzled to “appear moderate”.

    There’s no STATISTICALLY SIGNIFICANT difference between the model outputs and the actual measured temperature record for the earth’s surface.

    Now, go off and clean up and then work out what effect this phenomena has on the temperature output of the hindcast models to 2010 and check to see if it would be statistically significantly different.

  46. 46
    Completely Fed Up says:

    RS: “You need the application of heat for the equation to progress”

    Not really. As long as it is energetically favourable, you will get some combustion naturally.

    And I note this is quite a departure from your earlier comment that CO2 was NOT (categorically and emphatically!) a product of methane combustion.

  47. 47
    david adam says:

    Can you elaborate on why you give my guardian write up of this paper the thumbs down? I tried hard to get it right, and am happy to correct any mistakes
    david adam

    [Response: Hi David, It is probably nothing to do with you, but the headline and lede feed into two very common misconceptions – that climate models don’t deal with water vapour and that water vapour itself is a climate driver. It does matter that this is stratospheric water vapour and that this is an internal component of the system. – gavin]

  48. 48
    Theo Kurten says:

    Richard, your equation

    CH3O2 + H2O -> CH3OOH + O2

    is wrong. Clue: the hydrogen’s don’t balance, nor do the oxygens. That should be

    CH3O2 + HO2 -> CH3OOH + O2.

    Which is not a net sink of water, nor really a source of oxygen (where do you think the HO2 comes from?) Besides, if there is NOx available CH3O2 will react with NO instead, and give CH3O and NO2 (with the CH3O being rapidly oxidized further). This is all explained quite well in Wayne’s book that you quote. Wet deposition is one possible fate of CH3OOH, but not the only one; it can also be oxidized (like any other organic molecule in the air), or even photolysed. At least in the 3rd edition of Wayne’s book this is quite explicitly mentioned. A quick google search finds e.g. this recent study on the subject:

    Mark A. Blitz, Dwayne E. Heard, and Michael J. Pilling: Wavelength dependent photodissociation of CH3OOH: Quantum yields for CH3O and OH, and measurement of the OH + CH3OOH rate coefficient,
    Journal of Photochemistry and Photobiology A: Chemistry
    Volume 176, Issues 1-3, 14 December 2005, Pages 107-113.

    As both you and others have already noted, the oxidation pathway in the stratosphere is somewhat different. But the fact that oxidation of CH4 and other hydrocarbons in the atmosphere is (albeit via several steps, and with varying final yields due to deposition of some fraction of some intermediate products) a source of water and CO2 is well-known and quite basic atmospheric chemistry. I’m surprised that anyone that has read Wayne’s book would try to argue about this particular issue.

  49. 49
    Fred says:

    Something I’m not clear on. I had thought that satellite measurements of top-of-atmosphere radiation fluxes showed positive (heating) imbalance over the last 10 years, but the mystery was where the excess heat was going within the earth system (e.g., Trenberth, Curr. Opinion Environ. Sustain. 1, 19 (2009)).

    And when I read the Solomon paper, I understand that she and her co-authors are saying that decreased water vapor in the lower stratosphere meant there was a larger outgoing LW flux than had been previously believed, so there was no excess heat accumulating in the earth system.

    These two statements seem contradictory, so clearly there’s something I didn’t understand correctly.

    If an expert could clarify where I’m in error, I’d be grateful.

  50. 50
    Bob says:

    #10 Jimbo, #40 Anand:

    I don’t actually think that the Nature paper is quite off topic. Both it and this post (Solomon et al) discuss two papers that reveal specific measurements/mechanisms for negative feedbacks (as opposed to works like Lindzen, which try to prove that such feedbacks exist without actually zeroing in on them). These are obviously important studies, because the whole equation of climate sensitivity shouldn’t be guessed at by hoping or fearing one way or the other. The answer is to, over time, identify, qualify and quantify all of the mechanisms, and so be able to truly project our future.

    Me personally, I have a 15 year old daughter, and I’m cheering/hoping for negative stratospheric and CO2 feedbacks for her sake that keep things from getting as bad as it looks like it could (to me) in the long run.

    Obviously, “deniers” are being silly when they scream that we don’t know everything, so we can’t predict anything. Obviously we don’t, and we can. And I’d be really, really scared if we didn’t discover some (actually lots of) negative feedbacks along the way. If all we found were positive feedbacks, I’d start to find it hard to get up in the morning.

    With that said…

    The Nature paper only seems to refer (caveat: I didn’t read it, no Nature subscription, so I’m going from the abstract and BBC/Science Daily articles) to an 80% reduction in the positive CO2 feedback, not an 80% reduction in all positive feedbacks (e.g. water vapor, albedo). I also accept the caveats by Schellnhuber and Lenton in the BBC article, stating that the study probably doesn’t consider all mechanisms, like “anthropogenic activation of permafrost carbon or methane clathrates”, and that being based on paleo-data it doesn’t necessarily reflect a system like ours, undergoing as rapid a change as we are seeing now, so it may or may not apply as a template for this situation (very rapid anthro-CO2 increase).

    Similarly, the Solomon paper (again, couldn’t read it) discusses something that’s happened in the last decade, and may be either a transient or long term effect. Until the mechanism (instead of merely the observation) is understood, we can’t say whether it will help us long term, or is just slowing things down for the moment. But I think it’s important in that it goes a little towards answering that favorite Trenberth quote the denialists like to dredge up from the hacked e-mails: “The fact is that we can’t account for the lack of warming at the moment and it is a travesty that we can’t.”

    The point is… this is how science works. More and more people find real things to work out, and over time we work them out, and eventually we improve the quality and certainty of our predictions.

    For deniers to jump on either of these two papers and start screaming “see! see!” is just annoying.

    I have to say, I label myself (privately) as a “skeptic”, but I can’t use the term, because deniers have absconded it and twisted it to their purposes. But I’m a layman (2/3 degree in chemistry) who takes nothing at face value. I visit sites from both camps. For everything I read, I look for more, and when that seems to explain/debunk it, I look for more, and keep going, until I’m perfectly secure in my own knowledge and opinion. It’s still only a layman’s POV, and so incomplete, but it’s not simply what I’ve been asked to accept, or worse yet, just as much as I need to find to confirm my own desires, and nothing more.

    That said… I’ve never once seen a denial argument pan out. They can be cleverly constructed so they take a lot to untangle, but they never ultimately come to anything.

    Both of these papers are good, solid pieces to the puzzle.