Shindell, Methane, and Uncertainty

Guest Post by Willis Eschenbach

http://www.gsfc.nasa.gov/gsfc/earth/pictures/hansen010302/methane.jpg

Image: NASA Goddard Spaceflight Center

A recent study by Shindell et. al, entitled Improved Attribution of Climate Forcing to Emissions, (Science Magazine, 30 October 2009, Vol. 326) reports on interactions between aerosols and methane and other greenhouse gases. It has been discussed on Watts Up With That here <http://wattsupwiththat.com/2009/10/31/an-idea-i-can-get-behind-regulate-methane-first/>, as well as on other blogs. The Shindell study gives new values for the “radiative forcing” of various greenhouse gases. The “radiative forcing” is the increase in greenhouse radiation which is due to the increases in greenhouse gases since 1750.

UPDATE: The remainder of this article has been removed at the request of the guest author, Willis Eschenbach. During discussion, an error was discovered (see comments) and rather than leave this article with that error in place which may possibly mislead somebody in the future (if they didn’t read through comments) I’m honoring Willis’ request for removal. The comments remain intact. – Anthony

Advertisements

105 thoughts on “Shindell, Methane, and Uncertainty

  1. Obviously you know nothing about statistics or economics. You can’t draw conclusions from comparing uncertainty ranges of different studies. In any case, pointing to a study that found a HIGHER sensitivity to methane than past studies, and claiming that the disagreement proves there is ZERO sensitivity to methane, is a logical fallacy.
    And, 73% of economists agree that uncertainty INCREASES the economic case for climate legislation.
    http://akwag.blogspot.com/2009/11/dont-believe-global-warming-scientists.html
    Who’s the alarmist now?

    • WAG:
      From your link:

      The law school’s Institute for Policy Integrity sent surveys to 289 economists who had published at least one article on climate change in a top-rated economics journal in the past 15 years.

      No selection bias there. Nope. You might as well be surveying Real Climate moderators.

  2. That it be CO2, methane, ozone or even N2O, this is totally irrelevant to talk about greenhouse gases and their radiative forcing in view of the previous story. Regardless of man made or even natural emissions, the global temperature seems to be going down anyway.

  3. The IPCC Summary for Policy Makers states quite baldly on page 4 that the Level Of Scientific Understanding (LOSU) of the effects of aerosols, and changes in surface albedo from land use, is “medium-low.”
    The report does not claim “high” LOSU for any Radiative Forcing Components except “Long-lived greenhouse gases” (includes methane and CO2).
    Assuming their estimations of the level of scientific understand are correct, then how in the heck do you get so certain about a combined level of anthropogenic forcings, when many of the forcings are not well understood scientifically?
    This does not compute. In essense they are saying, “We are uncertain about the level of the forcings caused by various major factors. But we are certain about the combined effects.”
    Lunacy.

  4. And we should remember that for all practical purposes methane levels stopped rising ten years ago.
    And if that rise was as the IPCC claims due to human activity what was it we stopped doing ten years ago?.
    Kindest Regards

  5. Economists have a well-known free market bias, so in the economist community, you would expect the authors with the strongest opinions on climate legislation–and hence those who published most frequently on it–to be those opposed to it. Remember, the study participants were publishing in economics journals, not climate journals, so if the peer review process produces any bias (assuming economics journals go through peer review), the bias would be against climate legislation, not for it.
    Also, it’s worth repeating that the original post here makes no logical sense. Within the uncertainty ranges of the climate sensitivities presented, the warming from methane would still be massive. Just because studies disagree on the magnitude of warming does not mean the correct value is zero. Really basic stuff.

  6. WAG (21:01:05) :
    In any case, pointing to a study that found a HIGHER sensitivity to methane than past studies, and claiming that the disagreement proves there is ZERO sensitivity to methane, is a logical fallacy.
    He didn’t claim that. What he said was the claims of *certainty* were obviously false.
    And, 73% of economists agree that uncertainty INCREASES the economic case for climate legislation.
    You can’t get 73% of economists to agree on anything, unless they’re all Keynesians — and then they’ll only agree that they’re Keynesians.

  7. a jones (21:26:17) :
    You beat me to it. Methane has a half life in the atmosphere of 7 years. The level has not risen for eleven years, so an equilibrium has been reached between methane generation and oxidation. There can be no more warming from methane. It does not matter that interaction with aerosols makes the methane warming effect 0.1, 1.0 or 10.0 degrees. In fact the higher the real number, the less the contribution that CO2 makes, and the less the contribution that CO2 can make from here.

  8. WAG (21:01:05), thank you for your comments.

    Obviously you know nothing about statistics or economics. You can’t draw conclusions from comparing uncertainty ranges of different studies. In any case, pointing to a study that found a HIGHER sensitivity to methane than past studies, and claiming that the disagreement proves there is ZERO sensitivity to methane, is a logical fallacy.

    I fear that either my writing is not clear, or that your reading is not clear. Where did I say that there is zero sensitivity to methane? What I wrote is that the latest study says that the forcing from methane is way, way outside the range given by the IPCC.
    Next, why can’t different studies be compared? If one study says variable A is 0.5 ±0.1 (99% CI), and another study says that variable A is 1.0 ± 0.3 (99% CI), what prevents us from comparing them?

    And, 73% of economists agree that uncertainty INCREASES the economic case for climate legislation.
    http://akwag.blogspot.com/2009/11/dont-believe-global-warming-scientists.html

    So economists believe in anthropogenic global warming? I’m shocked, I tell you, shocked … but why should that concern us in the slightest? Science is not decided by consensus, thank goodness … and in particular, science is not decided by a consensus of economists.

    Who’s the alarmist now?

    I would say that at this point in history, anyone who believes that “the science is settled” about AGW is an alarmist. And I would say that when the IPCC doesn’t know basic facts, such as how much forcing comes from methane, anyone wanting to spend billions of dollars based on their “consensus opinion” is an alarmist.

  9. Uncertainties the way the IPCC treats them are not scientifically calculated.
    I keep giving this reference to AR4 chapter 8 , the physics case:
    More complex metrics have also been developed
    based on multiple observables in present day climate, and have
    been shown to have the potential to narrow the uncertainty in
    climate sensitivity across a given model ensemble (Murphy et
    al., 2004; Piani et al., 2005). The above studies show promise
    that quantitative metrics for the likelihood of model projections
    may be developed, but because the development of robust
    metrics is still at an early stage, the model evaluations presented
    in this chapter are based primarily on experience and physical
    reasoning, as has been the norm in the past.

    based primarily on experience and physical reasoning, as has been the norm in the past
    They admit it out in the open as well as in the last sentence of the quote of above:
    Note that a number of uncertainty ranges in the Working Group I TAR corresponded to 2-sigma (95%), often using expert judgement.
    I suppose it justifies “the norm in the past”.
    The spaghetti graphs are not error bars. They are according to the taste of the modeler clearly stated, so they cannot be sued . It is the small print.
    How are true statistical error bars given for a model to data fit? They are given by creating a likelihood function with the independent variables of the model and then maximizing it by varying the parameters within their errors. The output is a chisquare per degree of freedom, which should be near 1 for a many variable problem, and the error bars on the output values sought ( example would be the mass and the widths of resonances).
    What are the model runs? The modelers vary the parameters used to fit the temperature curve according to “their experience and physical reasoning” and make runs and give average values with their estimated by experience and physical reasoning feelings. Then a lot of such models are put on a graph, and voila a seemingly error band around the fitted temperature curve.
    It means next to nothing.
    WAG (21:01:05) :
    Obviously you know nothing about statistics or economics. You can’t draw conclusions from comparing uncertainty ranges of different studies. In any case, pointing to a study that found a HIGHER sensitivity to methane than past studies, and claiming that the disagreement proves there is ZERO sensitivity to methane, is a logical fallacy.
    I am sorry, but error bars are calculated just so that one can compare and make conclusions from different studies. That is the function of error bars and you are displaying your level of knowledge

  10. Put three economists in a room and get five opinions.
    Put a dozen ‘climate scientists’, as they grandly style themselves, and get one opinion, they need more money to perform some elaborate mystical ritual to avert climate catastrophe.
    Which is not to say there are not many honest scientists working to discover what is happening. There are.
    But what is science against these charlatans and mountebanks who claim to control the weather, past and future, and for all time?
    Provided you pay them of course. And they don’t come cheap.
    Kindest Regards

  11. Willis,
    Is your previous work on a new sensitivity calculation being reviewed? An update would be appreciated if you find a chance.

    This is the same situation as the certainty represented by proxy studies. The scientists use the annual differences of filtered proxies to generate a standard deviation by year of certainty each year. After the data has been filtered the bandwidth is massively reduced and the real uncertainty is very difficult to correct for.
    For proxy sticks in the end, one thing we can say for certain is that the ‘normal distribution’ based certainty is less certain than the true certainty of the signal.
    Stats are funny things.
    Today while playing around with sat data, I found accidentally that a ‘downslope’ in RSS satellite temperatures exceeded 95% statistical certainty for the past 8 years.
    http://noconsensus.wordpress.com/2009/11/09/statistical-significance-in-satellite-data/
    It wasn’t the point of the post but it is a strong downslope that doesn’t include 1998.

  12. Uncertainty’s truth is unspoken
    Real numbers still sleep unawoken
    It’s settled, the science
    Is all in compliance
    But science, dear reader, is broken.
    Reply: I am thankful that Hoboken did not appear ~ ctm

  13. Jeff Id (21:49:45), you ask:

    Willis,
    Is your previous work on a new sensitivity calculation being reviewed? An update would be appreciated if you find a chance.

    If you mean my work on tropical tropospheric amplification, I am rewriting it for submission to a journal. It’s slow because I hate doing that, it always feels like I have to lobotomize myself to do it, but such is science.

  14. Bill Tuttle –
    Ah, you’re on to something. You’re right, the author never *claimed* that the sensitivity to methane was zero–he *implied* it. He pointed out that there were two different estimates of the climate’s sensitivity to methane, and that therefore claims of certainty are “false” and “not valid,” and that “much is not understood” about climate. Of course, the uncertainty in the graph is whether things will be bad or really bad, not over whether methane affects the climate. But through clever use of language and misleading use of statistics, the author creates the impression that we don’t know anything about climate, and should therefore do nothing. It’s just what Steve McIntyre did to the hockey stick – when the error he pointed out was corrected, the shape of the graph didn’t fundamentally change, but he’d accomplished his mission, which was to sow the seeds of doubt. Same with Briffa’s study.
    Congratulations, you’ve just had your first lesson in denial 101: how to imply something without saying anything.
    Of course, if you’re getting your science advice from a TV weatherman, you might as well be getting your medical advice from Tor the holistic healer:
    http://akwag.blogspot.com/2009/11/youre-not-scientist-but-you-play-one-in.html

  15. “Well, the Shindell study first recalculated the values for the radiative forcing of a variety of greenhouse gases using the standard methods.”
    Can anyone post a link to these methods please.
    Since learning about Avogadro’s Law and number and moles etc. I can calculate the precise number of molecules of any “greenhouse” gas in a cubic meter of air at any temperature and density but I cannot find how to calculate the amount of longwave radiation absorbed, re-radiated or converted to heat by conduction. (the greenhouse effect)
    I do this purely as a hobby for when anyone raises the subject of “global warming” or “climate change” I talk knowingly of numbers like 6.022 times 10 to the power of 23 and radiation bandwidths in microns and they tend to go a bit blank 🙂

  16. Also, I stand corrected here by Willis:
    “Next, why can’t different studies be compared? If one study says variable A is 0.5 ±0.1 (99% CI), and another study says that variable A is 1.0 ± 0.3 (99% CI), what prevents us from comparing them?”
    Must have been the cold medicine speaking when I wrote that. thanks for pointing out the error

  17. eric anderson (21:16:10) :
    This does not compute. In essense they are saying, “We are uncertain about the level of the forcings caused by various major factors. But we are certain about the combined effects.”

    This sounds like “We can’t predict local weather but we’re certain we can predict Global Climate Change.”

  18. Frank (20:52:25) :
    Can I get an abstract or a summary in English please?
    Pretty pictures, though.

    Crystal clear to me, thanks WIllis.

  19. You follow a preacher through the gates of heaven, and follow his children through the gates of hell. Everybody knows that the preachers’ kids are the worst of the bunch…

  20. Shorter WAG: “You are responsible for my lack of reading comprehension! So you’re stupid!”

  21. WAG (22:39:12), you are absolutely wrong when you say:

    Bill Tuttle –
    Ah, you’re on to something. You’re right, the author never *claimed* that the sensitivity to methane was zero–he *implied* it. He pointed out that there were two different estimates of the climate’s sensitivity to methane, and that therefore claims of certainty are “false” and “not valid,” and that “much is not understood” about climate. Of course, the uncertainty in the graph is whether things will be bad or really bad, not over whether methane affects the climate.

    I implied nothing of the sort at all. I did not say it, I did not hint at it, I did not whisper it.
    My focus, as I clearly stated, is on the false claims of certainty by the IPCC. They said that they were 99% sure that the methane forcing was between 0.4 and 0.6. The recent study has shown that their claims of accuracy were totally unfounded. I bring this up as an example of the false certainty that the IPCC claims for its results.
    Despite your attempt to torture my words into another meaning, my statements were very clear. I did not say that this meant warming would be less bad or more bad. In fact, the authors of the study say (as they always do) that this will make little difference in the estimates of future warming. This is because (quite coincidentally I’m sure) their estimate of total forcing is not far from the IPCC estimate. The Shindell paper says:

    We calculated
    both the “abundance-based” RF owing to the net
    atmospheric composition response by species
    when all emissions are changed simultaneously
    and the “emissions-based” forcing attributable to
    the responses of all species to emissions of a single
    pollutant (Fig. 1). The sum of the forcings that take
    place via response of a particular species in the
    emissions-based analysis (each represented by a
    different color in Fig. 1) is approximately equal to
    the forcing due to that species in the abundance-based
    analysis. Likewise, the sums of all emissions-based
    and all abundance-based forcings are similar.

    This “coincidental” result, however, arises directly from the nature of the models used to do their calculations. Kiehl has shown that because of the way the climate models are tuned to match the historical temperature record, there is a close relationship between total forcing and climate sensitivity. As one goes up, the other goes down.
    In the Shindell case, they have run a model “in reverse” to calculate the forcings. But the nature of the models guarantees that they will end up with a total forcing which is similar to the IPCC forcings. When the models are run “forwards” to calculate temperatures, the IPCC forcings yield a given temperature pattern. So when they are run “in reverse” to calculate forcings, a given temperature pattern will of necessity give similar total forcings.
    However, this is meaningless to me. This is because I do not think that the change in the calculated methane forcings makes any difference at all, for the reasons that I explain in detail in my Thunderstorm Thermostat Hypothesis paper (q.v.). So your accusation, that I am trying to minimize the threat, is nonsense. I don’t think there is a threat from methane, but my reasons have nothing to do with the subject under discussion.
    In short, your ideas about what I am saying are very far from what I said. I have no axe to grind regarding whether methane forcing is larger, smaller, or zero. Please read what I said. You are more than welcome to comment on what I have written … but your comments about what you imagine I was trying to imply are very wide of the mark.

  22. Richard111 (22:58:47), you ask an interesting question:

    “Well, the Shindell study first recalculated the values for the radiative forcing of a variety of greenhouse gases using the standard methods.”
    Can anyone post a link to these methods please.
    Since learning about Avogadro’s Law and number and moles etc. I can calculate the precise number of molecules of any “greenhouse” gas in a cubic meter of air at any temperature and density but I cannot find how to calculate the amount of longwave radiation absorbed, re-radiated or converted to heat by conduction. (the greenhouse effect)
    I do this purely as a hobby for when anyone raises the subject of “global warming” or “climate change” I talk knowingly of numbers like 6.022 times 10 to the power of 23 and radiation bandwidths in microns and they tend to go a bit blank 🙂

    None of these radiative forcing numbers can be calculated directly. You have to use a climate model to calculate them. Of course, since we don’t understand the climate, to me it is somewhat circular to build a model of a climate system we don’t understand and then use the model to try to understand the climate system we don’t understand … but I digress.
    There is a handwaving description in the Shindell paper, viz:

    We used the composition-climate model
    Goddard Institute for Space Studies (GISS) Model
    for Physical Understanding of Composition-
    Climate Interactions and Impacts (G-PUCCINI)
    (6) to calculate the response to removal of all
    anthropogenic methane, carbon monoxide (CO)
    plus volatile organic compounds (VOCs), NOx,
    SO2, and ammonia emissions. This model couples
    gas-phase, sulfate (7), and nitrate (8) aerosol
    chemistry within the GISS ModelE general
    circulation model (GCM). Anthropogenic emissions
    are from a 2000 inventory (9).

    So the answer to your question is that the numbers you ask about are calculated by a random climate model of unknown accuracy which has never been subjected to the industry standard V&V and SQA testing (Verification and Validation, and Software Quality Assurance) … but then they claim that they know how accurate the estimates are, and report their claims to the nearest hundredth of a watt per square meter …
    Welcome to the wonderful world of climate science. If you want more accuracy, just add a bunch more untested models, and average the results!

  23. WAG (22:39:12)
    Congratulations, you’ve just had your first lesson in denial 101: how to imply something without saying anything.
    Nup. I had my first lesson in Denial 101 about forty years back, when Lib journos insisted the NLF had won the Tet Offensive…

  24. This whole discussion sounds like a Rumsfeld press conference…
    “there are certain uncertainties,
    and we are uncertain about certainties,
    but being uncertain about uncertainties, that we are certain of…”

  25. Willis Eschenbach (23:45:14) :
    Thank you for taking the time to respond. I had assumed my own incompetence in failing to find the information.
    So if warmists bug me I will ask “Please explain the exact mechanism that defines the radiative forcing of CO2 on the planets surface in watts per square meter?”
    I always assumed that information would be easily available in the science literature.

  26. Willis Eschenbach (23:45:14)
    ”Welcome to the wonderful world of climate science. If you want more
    accuracy, just add a bunch more untested models, and average the results!”
    Thank you Willis, I did that, and it really seems to work, looked out the window, suns shining, raining, 48°C ice and two and a half a meters of snow.

  27. I am more and more convinced, that the theory of “radiative forcing” is just hypothetical construction for explaining present temperature, which is caused by mere existence of bulk atmosphere. “Radiative forcing” on Mars is similar than here (no water vapor, but 15x more CO2 there) , and there is no difference between Martian blackbody and actual temperature. Hpowever, Mars has puny 600 Pa atmospheric pressure (95% CO2) compared to 100000 Pa on Earth surface.
    I am curious what to do, if methane is the main villain now.
    Fart.

  28. Maurizio @ ‘The Resilient Earth’ discusses this study nicely, too.
    ======================================

  29. WAG (22:39:12) :
    Bill Tuttle –
    Ah, you’re on to something. You’re right, the author never *claimed* that the sensitivity to methane was zero–he *implied* it. He pointed out that there were two different estimates of the climate’s sensitivity to methane, and that therefore claims of certainty are “false” and “not valid,” and that “much is not understood” about climate.

    I think I see your problem: You can’t speak English. Another example is the article you refer us to on your blog:

    it’s not just scientists who unanimously buy the climate consensus: 84% of economists also agree

    Hint: 84% is not unanimous. And above, saying that claims of a particular degree of certainty of any given value of X are false is not even remotely related to claiming that X is zero. No connection. No implication. No nothing. They are as unrelated as the concepts of 84% and unanimity.

  30. Re CO2=AGW, and measuring ‘radiative forcing’
    I wonder if anyone has done the experiment using a real greenhouse?
    AFAIK, commercial growers artificially increase the level of CO2 in their huge greenhouses because it boosts growth. Does it also decrease their heating bills?

  31. Willi Eschenbach, you have made a very simple mistake. In the study by Shindell et al. you find a different attributions of the radiative forcing. The emission based values mean that the effects of secondary greenhouse gases are redistributed to the primary greenhouse gases (those which are emitted). Of course, if you want to compare IPCC radiative forcings with emission based forces you have to add a major part of radiative forcing of ozone to the forcing of methane in the abundace based picture. And in this case you will easily see, that indeed there is not much of a difference between these two approaches. You should rethink your conclusion.

  32. Willis Eschenbach (23:45:14):
    “None of these radiative forcing numbers can be calculated directly.
    You have to use a climate model to calculate them. f course, since we
    don’t understand the climate, to me it is somewhat circular to build a
    model of a climate system we don’t understand and then use the model
    to try to understand the climate system we don’t understand…”
    etc. etc.
    Willis, thanks for this. It’s a great relief. Now, finally, I understand why I don’t understand “climate science.” The climate model business reminds me of the Marxist claim that they have penetrated the secrets of the laws of history (i.e. “the historical science is settled”) and can therefore – what?
    Tell the rest of us what to do, of course, and use force whenever we dare to object!

  33. We know that the climate scientists have a propensity to exagerrate the impact of greenhouse forcing and downplay the impact of other factors on the climate. Anyone can come up with a hundred examples of this.
    We also know now that the uncertainty ranges for the greenhouse forcings is larger than previously thought.
    Let’s assume that all the greenhouse forcings are on the low end of the uncertainty ranges then (given the past propensity to exagerrate).
    Now we are back to 1.0C to 1.5C per doubling. Given the past propensity to downplay the impact of other climate factors, now we are getting closer to what has actually occurred in the climate.

  34. WAG,
    “It’s just what Steve McIntyre did to the hockey stick – when the error he pointed out was corrected, the shape of the graph didn’t fundamentally change.”
    Have you got a link to this, the MHB98 graph that doesn’t change even when corrected for a) weighting of 390 for a particular bristlecone sample and b) an algorithm that produced a hockey stick shape using red noise?
    If you have such a graph, then why don’t you rush it over to IPCC headquarters? – I’m sure they would love to see it.

  35. WAG the Liberal Southern Baptist appears to be of the Holy Roller” ilk of the Warmist religion. He has seen the “Consensus”,and it is Good, Praise be to Gore.
    We here are all unwashed sinners and he is here to “save” us.
    Please, do teach us, O Knowledgeable One!

  36. Bill Illis,
    You are still assuming only greenhouse gasses caused almost all of the rise over the last century. Even AGW supporters assume only most of the change since 1940 or so is GHG caused, and this is only 0.3C or so. There is no reason to not find almost all of the rise as natural variability, especially in light of the recent decade of leveling and even dropping level even though CO2 is still rising. This leads to a maximum value of 0.5C or less per CO2 doubling (in line with Linzen’s approximation), and it may even be lower.

  37. supercritical (04:11:01) :
    “Re CO2=AGW, and measuring ‘radiative forcing’
    I wonder if anyone has done the experiment using a real greenhouse?
    AFAIK, commercial growers artificially increase the level of CO2 in their huge greenhouses because it boosts growth. Does it also decrease their heating bills?”
    Not sure what you ask would prove too much about climate even if a saving in heating were made. The whole point of a greenhouse is it is an enclosed environment. The atmosphere, however is unbounded and won’t respond in the same way to extra CO2.

  38. WAG (21:26:32) :
    Economists have a well-known free market bias, so in the economist community, you would expect the authors with the strongest opinions on climate legislation–and hence those who published most frequently on it–to be those opposed to it. Remember, the study participants were publishing in economics journals, not climate journals, so if the peer review process produces any bias (assuming economics journals go through peer review), the bias would be against climate legislation, not for it.
    (…) Congratulations, you’ve just had your first lesson in denial 101: how to imply something without saying anything.

    I just love the drive-by crowd.
    Let’s try and slow you down a little. I know that over on RC anyone who questions anything is part of the sinister “industry funded denial lobby” but if you would like facts not dogma – here is a list of the members of the European Climate Exchange (pdf). I see “big oil” (BP, Shell). I see Goldman Sachs, Barclays and HSBC.
    Economists have a well-known free market bias (…) the bias would be against climate legislation
    Yes, I see that now. Drive-by 101: at least make an effort. (and try not insulting your host until your final post)

  39. ************************
    WAG (21:26:32) :
    Also, it’s worth repeating that the original post here makes no logical sense. Within the uncertainty ranges of the climate sensitivities presented, the warming from methane would still be massive. Just because studies disagree on the magnitude of warming does not mean the correct value is zero. Really basic stuff.
    ****************************
    WAG – It is just these kinds of overreaching conclusions and statements that are causing warmists to lose credibility. The guy didn’t say the effect was zero – you did. But he did adequately illustrate that the uncertainty is not being correctly quantified, which was his point. You warmists just pull stuff out of the thin atmosphere.

  40. Ron House –
    thanks for pointing out the grammatical error of 84% not being “unanimous.” I’ve corrected the entry to read “nearly unanimously.”
    Incidentally, that’s also a good illustration of the point I’ve been making – the difference between what was strictly said vs. the implications/conclusions of what was said. While I was wrong in a grammatical sense to say that 84% constituted unanimity, correcting the language has no effect on the conclusion, which is that an overwhelming majority of economists believe global warming is real and its effects on the economy will be negative.
    When we talk about climate science, we’re ultimately trying to decide what we should DO: pass legislation or do more of the same. The implication of this post is clear: uncertainty means we should do nothing. Models disagree as to the precise degree of warming we should expect from methane, so the “science is not settled” and we are “not certain about the climate.” Note that this is not the same as claiming that the studies prove there is zero relationship between methane and temperature. But the insinuation is there: that the studies cast doubt on the legitimacy of the climate science consensus, and that this doubt is enough to justify inaction. The author makes this abundantly clear in a comment, stating that “anyone wanting to spend billions of dollars based on their ‘consensus opinion’ is an alarmist.”
    If a doctor tells a football player that he’ll die if he has 2 more concussions, and different doctor tells him that he’ll die with just 1 more concussion, the disagreement doesn’t mean the “science is not settled” as to whether continuing to play football poses a risk to the player’s life. Similarly, pointing out uncertainty on the extent of warming we’ll see is not grounds to conclude we don’t have enough certainty to take action.

  41. *****************
    WAG (06:29:33) :
    When we talk about climate science, we’re ultimately trying to decide what we should DO: pass legislation or do more of the same.
    ***************
    WAG – You hit the nail on the head there. Doing something in this case carries a huge cost. It has already cost the country 150 new coal plant, an aluminum plant, and that is just a small part of the cost already. New climate-change based legislation will cost much more than that. The science has to be dead certain that we will have catastrophic warming before we take any action. We have lots better things to do with the money that is lost to climate-change initiatives like solar and wind and all the other stuff that goes with it. And we need the energy to run our economy and ensure our safety. The science MUST be certain!!

  42. WAG (06:29:33) :
    >>When we talk about climate science, we’re ultimately trying to decide what we should DO: pass legislation or do more of the same. The implication of this post is clear: uncertainty means we should do nothing.<<
    I'm going to make a wild ass guess that you were indoctrinated by government schools and enjoy making and ass of U and ME.
    I'm not going to speak for anyone else here, but you're assuming that I believe that "do nothing" is the only possible alternative when faced with mother Gaia's implacable changes. That couldn't be further from the truth. I believe that humans have advanced far enough in intelligence to adapt to whatever mother Gaia comes up with.
    If, as is your evidenceless belief makes you hope, mother Gaia is warming due to human activities, humans can make the appropriate changes to their environment to cope with changes in temperature, sea level, and glacier melt.
    If the evidence of cooling temperatures and lack of solar activity are persuasive, mother Gaia is very near to tipping into another ice age, and humans will use the energy sources they've been discovering for millennia to warm themselves in place, and/or transport themselves to more tropical climes.
    "Do nothing" is a straw man option. As someone who is attempting to participate in a rational debate, WAG, you should be ashamed of assuming that your opponents all propose it as the counter to tyrannical and economically destructive legislation.

  43. Since the greenhouse carbon dioxide generators I have read about burn either a bit of propane or natural gas to obtain the added carbon dioxide, I am quite certain that this burning increases the temperature within the greenhouse. Carbon dioxide concentrations rose, as did the temperature inside the greenhouse, so the correlation between the increased concentration of carbon dioxide gas and the temperature increase is quite clear.

  44. WAG
    If a doctor tells the player that he will die if he has 2 more concussions, and he has had none, what does his statement mean? Your problem is the assumption that the concussion existed in the first place.
    Measurements not models rule physics and the hard sciences. Playing games with non-verifiable models is the scientific equivalent of playing video games with the super computers.

  45. In Italy my brother runs a 1.6 Rover on Methane, if he fills the tank with gasoline he pays €68.00 and get about 550km if he fills with Methane he pays €10.00 and gets about the same, like millions of Italians he is a devout Methane man ( his city of 7,000 people has 2 methane distributors )

  46. Uncertainty intervals depend upon all kinds of assumptions about the nature of the sample and how that sample relates to the underlying population of datapoints and the nature of that underlying population, etc. If we’re talking uncertainty ranges of variables that are estimated from others (using some “model”; i.e., formula), we’ve introduced an entirely new class of issues: relationship uncertainties (linear/ not linear, for one). Bottom line, there is some sensibility in talking about uncertainty ranges for direct measurements of phenomena, but that still is not easy to do and it is not logically entailed by any means whatsoever — lots of assumptions are involved. Thus, to talk about uncertainty ranges for temperatures as a result of CH3 (or any kind of) forcing as though doing so provides some “certainty” as to what is possible, is pure nonsense. You can do it, but it means little for poorly characterized relationships (such as chemical and radiative interaction in the environment). It’s amazing how bad so many scientists seem to be at understanding the fundamentals of inferential statistics. Sigh.

  47. WAG,
    Paraphrasing your first ( rather tasteless) sentence, you obviously don’t know anything about grammar. Assuming that 73% is equivalent to unanimity is not a grammatical mistake, it’s a semantic one.
    I have a metaphor as puerile as yours; when mechanic #1 says my car will go another 100,000 miles and mechanic #2 says it will go another 100 miles, they’re basically saying the same thing.

  48. @WAG. About forty years ago someone said that if you laid all the world’s economists end-to-end no two of them would agree on anything. But it would be a good start.
    Viewing the events in the world economy over the last three years has greatly reduced my confidence in the ability of economists to calculate anything other than a way out when the markets crash.
    The “economy” is a chaotic system, the climate is a chaotic system, and neither is understood to the level of anything being decided.
    BTW, your courtesy level calculates at minus 1.

  49. Tenuc (05:41:41) :
    The point is, does anyone really know the actual effect of increasing CO2 in the atmosphere?
    I would be really surprised if this hasn’t already been done, but I propose a simple experiment using a commercial greenhouse. The temperature should rise with added C02. It would be nice to know the shape of that function, wouldn’t it?
    Then, a further experiment could be run to include a shallow pond, and to increase the humidity by sprays to simulate rain, to tell us whether Henry’s law actually works or not, as well as giving some idea of the real airborne lifetime of added CO2 molecules.
    Then we could look at other stuff such as methane, decreasing O2, and other related conjectures.
    And I take your point about scaling, but we CAN say that the measured experimental effects would be a lot less in the Real World … maybe even vanishingly small/negligible!
    So I suggest that this kind of experiment would be relatively cheap to do, and very quick. It could be funded directly via small donations from skeptics, and would be just the thing for the MSM and the Blogosphere to follow in real-time.
    The hell with computer modelling! Let’s do some proper experiments we can all see!

  50. My thanks to all who are participating. Let me divide my responses up into several posts about different important issues.
    CIVILITY
    First, let me make a heart-felt plea for civility. There is a huge difference between saying “You are wrong”, and “You are wrong, you idiot.” Speculations about another poster’s mental abilities, proclivity for error, ancestry, level of education, and motives for posting have no place in a discussion of science. Please accord all posters the basic courtesies.
    In particular, this applies to what we say to/about people like WAG. Unlike many people who only post on sites where they get agreement, he has come here to present an opposing point of view. This is both desirable and laudable, as it is the heart of what science is about. I toss out my ideas, and other scientists try to knock them down. That is how science advances.
    So let us make everyone welcome in a collegial spirit, without trying to second-guess them, without questioning their fitness to espouse their ideas, without commenting on their command of English or their supposed mental state. I invite you all to focus on the ideas, and not on the people who put them forward.
    Finally, please do not respond “in kind”. The fact that a poster may be discourteous to us does not give us the right to be discourteous to them.
    We now return you to your regularly scheduled programming …

  51. UNCERTAINTY

    WAG above espouses a frequently-seen point of view about uncertainty:

    The implication of this post is clear: uncertainty means we should do nothing.

    While it is true that uncertainty does not mean we should do nothing, it also does not mean that we should do something. If your doctor says “We’re not certain what’s wrong with you, so we’re going to perform open-heart surgery”, you would be justified in refusing.
    Much of this confusion stems from a misunderstanding of the Precautionary Principle. This Principle is widely misinterpreted. A bit of caution about the Precautionary Principle is in order. It is not just a restatement of “better safe than sorry”, nor is it ordinary caution.
    Let me start with an early and very clear statement of the “Precautionary Principle” (I’ll call it PP for short), which comes from the UN Rio Declaration on the Environment (1992). Here’s their original formulation:
    “In order to protect the environment, the precautionary approach shall be widely applied by States according to their capability. Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation.”
    This is an excellent statement of the PP, as it distinguishes it from such things as wearing condoms, denying bank loans, approving the Kyoto Protocol, invading Afghanistan, or using seat belts.
    The three key parts of the PP (emphasis mine) are:
    1) A threat of serious or irreversible damage.
    2) A lack of full scientific certainty (in other words, the existence of partial but not conclusive scientific evidence).
    3) The availability of cost-effective measures.
    Here are some examples of how these key parts of the PP work out in practice.
    We have full scientific certainty that condoms and seat belts save lives. Thus, using them is not an example of the PP, it is simply acting reasonably on principles about which we are scientifically certain.
    There are no scientific principles or evidence that we can apply to the question of invading Afghanistan, so we cannot apply the PP there either.
    Bank loans are neither serious nor irreversible, nor is there partial scientific understanding of them, so they don’t qualify for the PP.
    Finally, the Kyoto Protocol is so far from being cost-effective as to be laughable. The PP can be thought of as a kind of insurance policy. No one would pay $200,000 for an insurance policy if the payoff in case of an accident were only $20, yet this is the kind of ratio of cost to payoff that the Kyoto Protocol involves.
    On the other side of the equation, a good example of when we might use the PP involves local extinction. We have fairly good scientific understanding that removing a top predator from a local ecosystem badly screws things up. Kill the mountain lions, and the deer go wild, then the plants are overgrazed, then the ground erodes, insect populations are unbalanced, and so on down the line.
    Now, if we are looking at a novel ecosystem that has not been scientifically studied, we do not have full scientific certainty that removing the top predator will actually cause serious or irreversible damage to the ecosystem. However, if there is a cost-effective method to avoid removing the top predator, the PP says that we should do so. It fulfils the three requirements of the PP — there is a threat of serious damage, we have partial scientific certainty, and a cost-effective solution exists, so we should act.
    Regarding the proposal that we pump CO2 into the ocean (or take any action regarding CO2), while there is at least a theoretical threat of serious or irreversible damage, there is no partial scientific certainty, nor are there any cost-effective solutions in hand, including pumping the oceans full of CO2. At the moment, therefore, no action regarding CO2 is justified by the Precautionary Principle.
    So no, action on CO2 is not justified at this time. Instead, we should support what is called the “no-regrets” option.
    This is to take actions that will be productive regardless of whether or not CO2 is the problem. What most people forget is that we have all of the threatened catastrophes which the models say will come from CO2 are with us today — droughts, and floods, and disease, and famine, and rising sea level and the seven Biblical plagues, we have all of them right now.
    So the no-regrets option is to research and advance the knowledge and train people around the world in how to avoid the poverty and pain and suffering which comes from the vagaries of the climate today. That will pay huge dividends whether or not CO2 is the boogeyman. Doing that is the best way of preparing for an unknown tomorrow.
    And that is what we should be advocating. The “no-regrets” policy is the only policy that makes sense in the face of the uncertainty that WAG correctly points out above, which is very real. We are not certain about climate science … but that doesn’t mean we should waste billions of dollars on any possible solution.

  52. Willis,
    Correct me if I am wrong but a model was used to determine the sensitivity of methane; it was not derived from first principles? This is circular reasoning as you will always get the assumed value implied in the model. CC has forced me to dust off my “Radiative Heat Transfer” by Hottel. All the chem engineers out there will know this. When I compare CO2 and methane emissivities at the same value of partial pressure times path length, methane is about 1/4 of CO2. At equilibrium emissivity equates to absorptivity the key parameter in describing the “greenhouse” effect. As the methane conc is at least 1/100 of CO2 then methane contributes 1/400 to atmos absorption as does CO2 ie SFA. It is not hard to also create a greenhouse model in excel using the principles in the book. The atmos is just layers of absorbing/emitting media.

  53. THE FALLACY OF THE “EXCLUDED MIDDLE”
    This is a common mistake made by both sides in the debate. I’ll use WAG’s statement as an example, because it is to hand, but it is quite common from AGW opponents as well as AGW supporters:

    When we talk about climate science, we’re ultimately trying to decide what we should DO: pass legislation or do more of the same.

    The fallacy of the excluded middle is the assumption that we have listed all of the possible choices. In this case, they are listed as “pass legislation” or “do more of the same.”
    In the real world, however, there are often a plethora of other options. In this case they might include
    • put money into climate research to reduce the uncertainty.
    • pursue a “no-regrets” path of actions that will have benefit whether or not CO2 is the secret global thermostat.
    • put on a public education campaign to encourage the “three R’s” (reduce, re-use, recycle).
    • fund research into alternate sources of energy.
    and so on.
    I find myself falling into this fallacy all too often, and to fight it I have my “rule of two”. This is that whenever I list only two outcomes (e.g. “Are my writing skills that bad, or are you just pretending you don’t understand”) I am wrong. In general there’s a host of options and explanations for any real-world situation, and I ignore them at my peril.

  54. Coincidence? The leveling off of methane levels in the atmosphere seems to be in parallel with the (at least temporary) halt to temperature increase over the past decade. This makes sense, since the melting of permafrost is the most likely culprit in the past methane rise.
    May we then conclude that, while we don’t know the effect of methane on global temperature, we can be certain that rising temperatures will increase methane levels? Somehow, I don’t think that’s the result AGWers were looking for….

  55. Oliver – I admit, my initial remark was rather not tasteful. Willis has been respectful, and I should not have said it.
    But there’s still an interesting debate here over uncertainty and how much certainty we need before taking an action. Jim writes that “doing something carries a huge cost,” and therefore “The science MUST be certain!!”
    Barring the point that there’s no such thing as 100% certainty (any businessman will tell you that decisions must be made in uncertainty), I can turn this argument around and point out that the costs of climate legislation are also uncertain (and also rely on models). The Congressional Budget Office estimates that with cap-and-trade, US GDP will grow about 0.03%-0.09% per year more slowly. The National Association of Manufacturers’ worst-case estimate is 0.15% slower growth. And like past cost analyses of environmental regulations, neither of these models include the effects of technology – breakthroughs spurred by higher carbon prices that allow us to produce the same level of output with less energy (e.g. efficient manufacturing processes, cheaper solar panels, etc.). So models don’t agree on the exact costs of cap-and-trade, but they do agree that such costs will be relatively modest. And the dimensions of uncertainty – namely, how technology will respond to higher carbon prices – gives us reason to believe that the costs will be smaller than predicted. Why should we trust economic models and not climate models?
    The costs of global warming are also uncertain. However, there’s much more variation in these estimates. They range from modest (e.g. money spent building sea walls) to catastrophic (permanent droughts). And the dimensions of uncertainty – namely, feedbacks – have generally pointed to greater-than-expected warming as more is learned (the original post refered to an estimate of greater-than-expected sensitivity to methane). If humans lack the foresight to predict how interventions in the market affect national wealth, why would anyone trust our ability to engineer the workings of Nature without unintended consequences?
    The point is, while the costs of climate legislation fall within well-understood bounds (higher energy costs and short-term job losses), the costs of climate change range from modest to worse-than-expected to catastrophic to as-yet-unimagined. The economic crisis has taught us to ignore these long-tail probabilities at our own risk.
    And I still haven’t seen a defense of the logic chain that I originally criticized:
    “new study finds sensitivity to methane is higher than previously estimated –> scientists disagree over climate sensitivity –> the science is not settled –> we can’t be certain enough that we are causing climate change to justify action”
    You don’t need to be certain it’s 25 or 30 degrees outside (F) to know you should put on a coat, and whether forcing due to methane is 0.5 or 1.0 W/m^2 does not reduce our certainty that adding more greenhouse gases will warm the planet.

  56. Jörg Zimmermann (04:27:34), you raise a very interesting issue:

    Willi Eschenbach, you have made a very simple mistake. In the study by Shindell et al. you find a different attributions of the radiative forcing. The emission based values mean that the effects of secondary greenhouse gases are redistributed to the primary greenhouse gases (those which are emitted). Of course, if you want to compare IPCC radiative forcings with emission based forces you have to add a major part of radiative forcing of ozone to the forcing of methane in the abundace based picture. And in this case you will easily see, that indeed there is not much of a difference between these two approaches. You should rethink your conclusion.

    If there were no difference between the approaches, the paper would be meaningless. The difference is this:
    According to the IPCC, the rise in methane since 1750 has been the cause of a temperature rise of 0.48 w/m2 * 0.8°C/W-m^2 = 0.4°C.
    According to the new study, the rise in methane since 1750 has been the cause of a temperature rise of 0.99 w/m2 * 0.8°C/W-m^2 = 0.8°C.
    This is a significant difference, which (if one believes that GHGs are governing the earth’s temperature) has significant policy implications. Or as the Shindell study says,

    We found that gas-aerosol interactions substantially alter the relative importance of the various emissions. In particular, methane emissions have a larger impact than that used in current carbon-trading schemes or in the Kyoto Protocol.

    In other words, indeed there is a difference between the two approaches.

  57. Willis Eschenbach, very good article, and even better follow-ups (civility, uncertainty, excluded middle); all good things to keep in mind. The bit about the precautionary principle is a keeper.
    Uncertainty, to me, is the greatest weakness of the alarmist view. When dealing with something as complex as the earth’s climate system, a model that’s only partly right is wrong, period. Yet the IPCC uses an “ensemble” of models–only one of which at most can be “right”–to predict (excuse me, “project”) the state of an intricate system decades into the future. And these projections are used to justify doing certain harm now to prevent uncertain damage at some constantly-receding time in the future. If that’s not a good definition of insanity…

  58. WAG (22:39:12) : Thank you for the lesson in denialism. I’ve always wondered about the kind of mindset that would reject science and the scientific method. Your stream of consciousness narrative gives me at least some insight into how a denialist such as yourself operates. This will be invaluable in trying to counteract denialists such as yourself and RC.

  59. WAG,
    I appreciate the civil tone of your post, however I disagree with most of what you’ve said.
    As regards the logic chain that you find flawed, I would make the point that the credibility of an advocate is germane to an assessment of the advice given. In this case, putatively, not only were scientists wrong about CH4 but they were, therefore wrong about CO2, unless they were wrong about the total forcings, instead.
    The wider context of this dispute must be familiar to you; we don’t all agree on any aspect but, of course, the smaller the problem, the less urgent the remedy. I suspect there is absolutely no problem at all, but time will tell.
    In the meantime, it isn’t certain that adding GHG’s will warm the Earth, it isn’t certain that a warmer Earth is a catastrophe, but, perversely, it’s not certain that expending enormous amounts of wealth and energy on a non-problem would be an economic disaster. Most of the global economy is concerned with the pursuit of luxury to some degree, since all we really need to perpetuate our species is enough to eat and a secure place to hang out. Economic activity happens because people don’t have what they want, not what they need. If they want a warm fuzzy sense of saving a planet from themselves and they’re prepared to pay good coin for it, then let them fill their boots. As long as it’s not too much of my coin.

  60. Sorry, Willi Eschenbach, you still missed the point. In the IPCC radiative forcings you see ozone and stratospheric water listed beside methane. In the approach by Shindell et al. these compounds are no longer viewed separately. Methane is the primary pollutant, ozone and stratospheric water are secondary pollutants. In the emissions based approach you put the radiative forcings due to secondary pollutants on top of the radiative forcings of the primary pollutants. In the emissions based approach you will not see ozone or stratospheric water being listed separately. If you add the radiative forcings of methane and larger parts of ozone and stratospheric water from the abundance-based approach and calculate the error bars accordingly, you should come closer to the emissions-based approach. Simpler said, you compare apples and oranges.

  61. Jörg Zimmermann (04:27:34), a further thought on the question.
    If the initial estimate of the uncertainty of the forcing of methane and the other forcings had been correct, the uncertainty intervals would have overlapped after the “effects of secondary greenhouse gases are redistributed to the primary greenhouse gases “.
    The fact that they were not overlapping shows that the uncertainty estimates were too narrow.
    The uncertainty, of course, did not allow for our lack of understanding of the climate.
    In addition, the uncertainty (both the old and the new) is obtained in a most curious way — from the variation in the results of different climate models.
    However, this is not a measure of the uncertainty of our estimates of the underlying variable. It is merely a measure of the spread of the models, which may simply represent a commonality of shared incorrect assumptions …

  62. so CO2 is 24.14 times as effective in warming the earth as is stratospheric water.
    Is that stratospheric CO2 versus stratospheric water; and what is the local ambient temperature at that stratospheric zone; in other words is the stratospheric H2O in gaseous form, or liquid or solid form.
    What on earth is the significance of stratospheric trace gases, since it is generally considered that the major GHG effect of say CO2 is in just the first few metres at ground level; and presumably the same goes for water vapor.
    My last question would be; are those radiative forcing Watts/m^2 values the same all over the globe or is there say a latitudinal variation; it just doesn’t seem rational that there is as much W/m^2 available to trap by CO2 (or methane or stratospheric water) at the poles as there is over say a tropical African or middle east desert.

  63. I hate to even ask how many stations there are all over the globe that have the necessary equipment to measure the local radiative forcing W/m^2 contributed by each of the major GHGs. Something tells me that without proper mapping of the local values, it would not be possible to compute a (credible) mean global value.

  64. “”” WAG (22:39:12) :
    Bill Tuttle –
    Ah, you’re on to something. You’re right, the author never *claimed* that the sensitivity to methane was zero–he *implied* it. He pointed out that there were two different estimates of the climate’s sensitivity to methane, and that therefore claims of certainty are “false” and “not valid,” and that “much is not understood” about climate. “””
    “””” You’re right, the author never *claimed* that the sensitivity to methane was zero–he *implied* it. “”””
    Well not exactly; maybe YOU inferred it !
    Since you alone raised the issue, statistics suggests that that is the more likely explanation.

  65. Willis Eschenbach: I haven’t been through the other comments. Sorry if this is a duplicate comment or if it belongs on an earlier thread.
    As I was reading your post, it occurred to me that Shindell et al were trying to rearrange greenhouse gas attribution in an attempt to explain the recent flattening of global temperatures and OHC. Since methane was relatively flat from 1998 to 2006…
    http://www.esrl.noaa.gov/gmd/aggi/aggi_2009.fig2.png
    …it appears they’re trying to make it the dominant greenhouse gas.

  66. Mr. Eschenbach,
    I agree with the comments of Zimmerman that you are comparing apples to oranges. The values for “Abundance-based” and “emissions-based” are coming out of the same models; they are different from each other because they include different things: they are defined differently. The total RF from all forcings is about the same in the two cases; they are just distributed differently. In the “emissions-based” metric, methane gets credit for effects it has on atmospheric chemistry.
    Note that tropospheric ozone does not have its own bar on the emissions-based chart. The point is that IPCC reports assign a RF value to tropospheric ozone, but ozone is not directly emitted by industry; it is formed by reactions involving CO, VOCs including methane, and NOx. Roughly speaking, the emissions-based view thus divides up the contribution of tropospheric ozone among the components that react to form it. Hence, methane gets a RF boost. This is to help guide policy, as perhaps the reader may not know that methane, CO, NOx and other VOC emissions lead to the production of low-level ozone. This is not a reflection of the uncertainty on the role of methane; nor does it signal any sort of big mistake in past RF values for methane.
    If you want to compare apples with apples, then compare the FAR value with the ‘abundance-based’ value, as those are defined in the same way. You’ll see them to be similar.

  67. Bob Tisdale (14:03:12), good to hear from you. You say:

    As I was reading your post, it occurred to me that Shindell et al were trying to rearrange greenhouse gas attribution in an attempt to explain the recent flattening of global temperatures and OHC. Since methane was relatively flat from 1998 to 2006…
    http://www.esrl.noaa.gov/gmd/aggi/aggi_2009.fig2.png
    …it appears they’re trying to make it the dominant greenhouse gas.

    Having been accused of having nefarious motives quite often (including in this thread), I prefer to avoid speculation on the motives of the scientists involved. While what you say may be true, it also may be very untrue, and unfair to the scientists involved. I try to ascribe good motives to everyone unless there is strong evidence otherwise.

  68. George E. Smith (13:40:40) :

    I hate to even ask how many stations there are all over the globe that have the necessary equipment to measure the local radiative forcing W/m^2 contributed by each of the major GHGs. Something tells me that without proper mapping of the local values, it would not be possible to compute a (credible) mean global value.

    Since you didn’t ask, I believe that the answer is “none”. As far as I know, given our current measuring devices, it can’t be measured from the ground, or from the air, or anywhere. It can only be estimated from a computer model.
    I’d be glad to be proven wrong on this one, however.

  69. Does W/m^2 have any relation to atmospheric pressure? Would the value of a forcing fluctuate if atmospheric pressure changed?

  70. Willis: The closest thing to a directly measurable radiative forcing is that due to changes in solar irradiation. Satellites can measure the change in incoming radiation; you then account for whatever fraction is reflected, and the basic fact that the earth is round. Even here, you need a model to get further in the detail.
    Bob Tisdale: I think your hunch is on the wrong track. If a modeler wanted to crank down the amount of warming in the model, he’d reduce the total forcing somehow. That’s not what’s happening here. The total forcing is about the same; the amount due to CO2 is about the same. The authors are just relating the different forcings to emissions; they are normally more defined in terms of composition of the atmosphere, not composition of actual emissions. Due to chemical reactions in the atmosphere of the emitted compounds, these are not the same thing. Hence the paper.

  71. carrot eater (14:26:32), you say:

    Mr. Eschenbach,
    I agree with the comments of Zimmerman that you are comparing apples to oranges. The values for “Abundance-based” and “emissions-based” are coming out of the same models; they are different from each other because they include different things: they are defined differently. The total RF from all forcings is about the same in the two cases; they are just distributed differently. In the “emissions-based” metric, methane gets credit for effects it has on atmospheric chemistry.

    The issue is that the IPCC earnestly informed us that the effect of methane since 1750 was an instantaneous radiative forcing of 0.5 W/m2 ± 0.1 W/m2.
    This means that if there were no methane increase since 1750, the most that it would change the forcing is 0.6 W/m2.
    The current study, on the other hand, says that that if there were no methane increase, the least that it would change the forcing is 0.7 W/m2.
    Clearly, both of those can’t be right …

  72. “”” Willis Eschenbach (14:47:49) :
    George E. Smith (13:40:40) :
    I hate to even ask how many stations there are all over the globe that have the necessary equipment to measure the local radiative forcing W/m^2 contributed by each of the major GHGs. Something tells me that without proper mapping of the local values, it would not be possible to compute a (credible) mean global value.
    Since you didn’t ask, I believe that the answer is “none”. As far as I know, given our current measuring devices, it can’t be measured from the ground, or from the air, or anywhere. It can only be estimated from a computer model “””
    Just based on the extreme range of surface Temperatures on earth from about -90C (183Kat Vostok) to about +60 C (333K in tropical deserts) the bounds for Black Body limited Stefan-Boltzmann thermal radiation cover a range of about 11:1. Throwing in variations in spectral emissivity, may extend or contract that range.
    So a given amount of any target GHG over such a site; would presumably yield something like an 11:1 range in forcing for the exact same amount of a given GHG species.
    Actually it is worse than that; because as a result of that 183 to 333 K extremes of Temperature, the peak of the BB like spectrum also varies by a factor of 1.82; and the spectral radiant emittance at that peak varies as the fifth power of temperature rather than the fourth. Then you get a 19.95:1 range of peak thermal emittance; and that spectral peak moves even further away from at least the CO2 13.5 to 16.5 micron absorption band. Now that of course results in enhanced cooling past CO2 GHG trapping in the hottest regions, and enhanced trapping by CO2 in the coldest locations where the emission spectral peak sits right on the CO2 band at 15 microns.
    Then you also need to factor in that the Doppler broadening of those absorption bands tends to go as the square root of the Temperature (Kelvins), and that will add further to the high temperature absorption, and further depress the low temperature absorption due to the narrower band of the absorption bands.
    In any case; radiative forcing hardly seems suitable as a global constant for any species of GHG
    Which is why I find the whole Arrhenius concept of “climate sensitivity” to be rather silly.

  73. Algebraic-Hypnotics 101 Primer
    Academic statisticians “succeed” by hypnotizing their victims with volumes of algebraic abstraction. This concentrates power in their clan.
    Practical consequences:
    1) bad management,
    2) bad policies,
    3) etc., etc., etc. …
    … i.e. intolerably costly for individuals, society, & civilization.
    Clarification:
    Data analysis (& *descriptive stats) is indispensable.
    It is misapplied statistical *inference*, based on untenable abstract assumptions, that runs individuals, society, & civilization off-the-rails.
    For those who lack the background to identify statistical inference:
    Look for “error bars”, “confidence intervals”, “p-values”, “statistically significant”, & related “uncertainty” terms/measures.
    No matter how well “mathematically defined” these things are, they are all based on abstract assumptions, which are not necessarily tenable in reality [for example in biological & climate systems].
    Conclusions cannot be divorced from assumptions. Due diligence in assessing assumptions is not a part of the mainstream “p-value” “error bar” “confidence interval” culture that has gripped the scientific community as a major multi-decadal fashion.
    Here’s an example of how it goes:
    Say a medical expert & a stats expert are working together on a timeline…
    Assessing abstract assumptions used in inference requires intimate subject-area knowledge. The statistician may not have this and so may decide to “go with it anyway and let the medical expert decide”.
    Abstract-assumption assessment also requires intimate understanding of stats models. The medical expert may not have this and so may decide to “go with it anyway and let the statistician decide”.
    And so we see a “hot potato” scenario …and keep in mind timelines, reputation, careers, grant money, etc., all of which have the potential to impact researchers families – plenty of motivation for 2 bright sparks to bluff a united front.
    Anyone who thinks the solution is as simple as educating interdisciplinary hybrids is failing to appreciate how complex the realm of mathematics & statistics is. The solution is the careful application of common sense & appropriate qualifiers – along with sober, insightfully-penetrating [as opposed to malicious] audit by independent parties lacking conflict-of-interest.
    We don’t all have multiple lifetimes to become cutting-edge experts in multiple fields, but that need not imply that our common sense should obediently & uncritically succumb to the wizardry of algebraic-hypnosis.

  74. Willis, You are looking at the wrong graph in the IPCC AR4 report. Figure 2.21 is the emissions-based forcings, not figure 2.20 (which is the abundance based calculation). Jorg is correct – you are not comparing like with like.

  75. Willis: MASSIVE OVERSIGHT!!!! You have missed one key part of the IPCC chapter 2 in the Fourth Assessment Report: namely, pg. 205 Figure 2.21 and pg. 207 Table 2.13 both show the IPCC assessment of an “emission based value” as versus the 0.48 from the “abundance based value”. And the result showed in this figure and table in the IPCC 4th Assessment Report was…
    0.856 W/m2!!!
    That’s 0.57 for CH4 (some is destroyed by NOx which is why it is larger than 0.48), 0.2 for ozone, 0.07 for stratospheric H2O, and a dab for contribution to CO2 from fossil methane. No sulfate or nitrate interactions estimated, but well within the Shindell uncertainty range for the emission based value. Therefore, in order to make your above post accurate and honest, you need to correct the figure to include the IPCC estimate (or retract the post).
    I’m also surprised that given the eagle-eyed scrutiny that posters on this board apply to any claim made by a “consensus” scientist, that not one has read the IPCC forcing chapter sufficiently carefully to notice that this number was in there in plain sight, in multiple places.

  76. Controversial because its heresy
    “New data show that the balance between the airborne and the absorbed fraction of carbon dioxide has stayed approximately constant since 1850, despite emissions of carbon dioxide having risen from about 2 billion tons a year in 1850 to 35 billion tons a year now.
    This suggests that terrestrial ecosystems and the oceans have a much greater capacity to absorb CO2 than had been previously expected”.
    http://heliogenic.blogspot.com/2009/11/controversial-because-its-heresy.html

  77. Oh. I see that both carrot eater and Zimmerman both beat me to the conceptual answer (eg, that Willis is comparing Shindell’s orange to IPCC’s apple), they just missed that IPCC kindly provided an orange as well so that in fact, we can do both apple to apple (abundance) and orange to orange (emission) comparisons.
    This isn’t to say that the Shindell study has not advanced the science, which it has, adding new interactions and showing how they might change the calculations of forcing going forward into the future (the IPCC GWP estimate for methane uses very rough approximations for ozone effects). It also doesn’t say that the IPCC error bars were perfect – in general, my baseline assumption is that error bars should probably always be a bit larger than they are. Of course, that baseline means that things might always be worse just as easily as they could be better.
    However, in any case, the thrust of this post, which is that the old IPCC result falls outside of the bounds of the new Shindell result, is clearly wrong, as carrot eater and Zimmerman both tried to argue.

  78. Oh, and Freddy beat me to the post too, and he included the actual Figure number. Oh, well. I also apologize for spelling Zimmermann’s name wrong. C’est la vie.

  79. Willis, let me try again.
    “Clearly, both of those can’t be right …”
    They are both right, or at least, they are consistent with each other. They are coming out of the same model. They are just different ways of describing the same physics.
    The lower RF value for methane is calculated from the direct impact of ~1800 ppb of methane itself. Forcing due to stratospheric water and tropospheric ozone are calculated separately, and listed separately. You can see that in both the IPCC report and “Abundance-based” forcings in this paper.
    However, increases in stratospheric water and low-level ozone are due, in part, to methane emissions. Methane reacts to form these compounds. So, the authors decided to group the radiative forcings in a different way, to emphasize which emissions lead to which forcings. Hence, methane gets not only its own direct contribution, but parts of the forcings due to stratospheric water and tropospheric ozone.
    The two different RF figures are expressing very different things, and thus they are different from each other. They are different by definition. Methane’s direct impact is x, +/- some error. Methane’s total impact is y, +/- some error. x and y will be different things. There is no inconsistency here.

  80. WAG (11:38:57) :
    So… we model the reaction of an economy we don’t understand to modelled actions we don’t understand in response to a modelled climate we don’t understand. Hey – what could go wrong?
    I’m sure it will all fall somewhere within well-understood bounds (or not)

  81. Marcus: many thanks for that; I totally forgot emissions-based figures are in the IPCC FAR. Yes, there’s a neat little table there on p207, showing the cross-interactions. In particular, the new paper adds interactions between sulphates and other species, beyond what was given at the time of IPCC FAR. But yes, this completes the loop. To really compare oranges to oranges, I’d remove the interactions considered in this paper but not the IPCC report.

  82. Willis,
    Of course, since we don’t understand the climate, to me it is somewhat circular to build a model of a climate system we don’t understand and then use the model to try to understand the climate system we don’t understand

    Now you’re implying that there is no climate!
    No.. really, I think that pretty much sums it all up.. particularly when both Lindzen and Spencer have demonstrated that all the models have water vapor feedback exactly wrong and all model predictions of catastrophic warming are due to water vapor feedback.

  83. Re: Decision making under uncertainty
    There’s a number of different methods that have been developed in different places for trying to make ‘optimal’ decisions when faced with uncertainties of different types, but pretty much all of them require some form of objective or utility function. That is, what is the ultimate goal that we’re trying to achieve. This should be set long before any discussion/disagreements about how the world works, and basically involves all parties to lay they cards on the table. This is where I believe everything will break down as I suspect it would be virtually impossible to get any sort of consensus about what humanity’s long-term goals should be amongst 200-odd world governments (of course it would be much easier if we only had 1 😉 ). e.g., status quo in terms of standard of living, getting 90% of the earths population above some magical poverty line, maintain healthy and functioning ecosystems across most of the earths surface (possibly to the ultimate detriment of humanity)?
    @ Paul Vaughan
    I agree that misapplied statistical inference causes problems, but without some form of statistical inference how do you propose that scientific (not statistical) hypotheses of interest can objectively be compared? Where possible, assumptions should always be checked using the observed data so that you can have some faith that your reported conclusion are not too far off the mark. Unless you have a situation that is completely deterministic, with no potential for measurement uncertainty, I don’t know how you can compare hypothesis without some form of statistical procedure. Descriptive statistics can be useful of interesting, but have limited ability to advance hypothesis driven science.
    As for your doctor and statistician example, yep, I’m sure that happens all the time and I’ve seen it happen, but that doesn’t mean people need to be an expert in both. It’s basically a communication problem. All fields have their own jargon which creates barriers. The parties need to either bring those barriers down themselves or find someone else to mediate (personally I’ve found beer to be very useful and breaking down such barriers, until I start babbling like a 6 month old). If people are too proud to admit they don’t understand something, then that’s an entirely different problem.
    Sorry for the slightly tangential post.

  84. Marcus (16:41:24), outstanding. This is why I love the web. You say:

    Willis: MASSIVE OVERSIGHT!!!! You have missed one key part of the IPCC chapter 2 in the Fourth Assessment Report: namely, pg. 205 Figure 2.21 and pg. 207 Table 2.13 both show the IPCC assessment of an “emission based value” as versus the 0.48 from the “abundance based value”. And the result showed in this figure and table in the IPCC 4th Assessment Report was…
    0.856 W/m2!!!
    That’s 0.57 for CH4 (some is destroyed by NOx which is why it is larger than 0.48), 0.2 for ozone, 0.07 for stratospheric H2O, and a dab for contribution to CO2 from fossil methane. No sulfate or nitrate interactions estimated, but well within the Shindell uncertainty range for the emission based value. Therefore, in order to make your above post accurate and honest, you need to correct the figure to include the IPCC estimate (or retract the post).

    Marcus, you are quite correct. This study did not say what I thought it said. My comments were 100% wrong.
    The study does add something new to the question … it adds 0.08 to the methane emission-based forcing, through methane’s interactions with nitrate and sulfate. Be still, my beating heart.
    I was misled by the fact that the study did not mention the IPCC emission-based forcing at all. Instead, they only referenced the abundance based forcings, and they only compared their results to the abundance-based forcings. I don’t know why, as it seems very relevant to the discussion. I was totally fooled by their claim that they had found something significant.
    In their Abstract, the authors say:

    We found that gas-aerosol interactions substantially alter the relative importance of the various emissions. In particular, methane emissions have a larger impact than that used in current carbon-trading schemes or in the Kyoto Protocol.

    “Substantially alter”? An addition of 0.08 W/m2 to the total methane forcing, from sulfate and nitrate interactions, doesn’t “substantially alter” anything. I am amazed that this trivial change, in the hundredths of a watt/metre squared, merited a scientific paper. How does this make any difference to anything? When I mistakenly thought that they were saying the methane forcing was doubled, “substantially alter” made sense … but a scientific paper for a 0.08 W/m2 difference? On what planet is this meaningful?
    I am also amazed that anyone thinks that current climate models can measure forcings to the nearest hundredth of a W/m2 … when we can’t measure the forcings directly, so we have absolutely no evidence to confirm the model findings.
    Finally, you say:

    I’m also surprised that given the eagle-eyed scrutiny that posters on this board apply to any claim made by a “consensus” scientist, that not one has read the IPCC forcing chapter sufficiently carefully to notice that this number was in there in plain sight, in multiple places.

    Sorry, Marcus, but that’s your job, to scrutinize things that seem wonky to you … and you have done it well. My congratulations. My job is to scrutinize things that seem wonky to me. I’m not surprised that you didn’t find the errors in the hockeystick, for example.
    This is the beauty of the opening of science to a much wider audience on the web, that both of us can look for (and sometimes find) errors that have not been found in the peer review process. This is how science advances, because both sides investigate the claims that they doubt for whatever reason.
    My thanks to you,
    w.

  85. To me, the most important quote from the IPCC FAR: “Best estimates are given where available.” Estimates? Doesn’t that mean POOMA* numbers?
    * Preliminary Order of Magnitude Approximation

  86. Willis, most science is incremental. The end numerical result of the paper might not seem impressive to you, but getting more aerosol chemistry into the models is one more thing they’ve got in there (how well they’ve gotten it there is hard to tell from this paper). Interactions like those between aerosols and clouds are another thing to improve, so aerosols really are of interest. Sadly, it’s just a short note in Science, so hopefully the details of the chemistry will be described elsewhere.

  87. “In particular, methane emissions have a larger impact than that used in current carbon-trading schemes or in the Kyoto Protocol.”
    That statement isn’t talking about the historical forcing, but rather the future forcings and therefore GWPs. _Those_ are changed more significantly by the paper (as I said in my first post, the methane chemistry was only included in a very rough fashion in the IPCC GWP estimation of “25”)

  88. carrot eater (19:21:57), you are quite correct when you say:

    Willis, most science is incremental. The end numerical result of the paper might not seem impressive to you, but getting more aerosol chemistry into the models is one more thing they’ve got in there (how well they’ve gotten it there is hard to tell from this paper). Interactions like those between aerosols and clouds are another thing to improve, so aerosols really are of interest. Sadly, it’s just a short note in Science, so hopefully the details of the chemistry will be described elsewhere.

    That’s why I was surprised (and misled) by them saying:

    We found that gas-aerosol interactions substantially alter the relative importance of the various emissions.

    Their result barely makes the “incremental” threshold, it definitely does not “substantially alter the relative importance”.
    In particular, I’m not impressed by results of this type from a model. This is less than incremental, it is totally unverifiable. Yes, their model says that the methane forcing increases, but we have no data with which to compare that. How can we conceivably put error bounds on that tiny number? How do we even know that the sign of the change is correct? But I digress …
    Thank you for your contributions to the thread. Our discussions here are another incremental step down the scientific path. My appreciation for your fighting my ignorance on this subject, and for your gracious and convivial tone.
    w.

  89. Marcus (19:49:41), you say:

    “In particular, methane emissions have a larger impact than that used in current carbon-trading schemes or in the Kyoto Protocol.”
    That statement isn’t talking about the historical forcing, but rather the future forcings and therefore GWPs. _Those_ are changed more significantly by the paper (as I said in my first post, the methane chemistry was only included in a very rough fashion in the IPCC GWP estimation of “25″)

    After rising for a number of years, the atmospheric methane emissions have levelled off during the last decade. Nobody knows why this has happened. Heck, nobody knows why they were rising prior to levelling off. Nobody knows which way they will go from here.
    As a result, any honest scientist would have to say that we don’t have a clue what methane levels will be a century from now.
    Yes, if we assume (as the IPCC and Shindell et. al do) that methane will start to rise again at some assumed value, it could make a difference. If their model is correct. And if methane levels rise. And if GHG forcing is the secret global thermostat.
    Since we have absolutely no independent confirmation of the accuracy of the model, and no idea what future methane concentrations will be, and no data or observations saying that temperatures are ruled by GHGs, that’s a big stack of “ifs” to be calling science.
    Thank you again, Magnus, for your contribution. Rather than merely state your ideas, you backed them up with clear citations to the literature. My hat is off to you.
    w.

  90. If you’re looking for significant change in the numbers, it’s probably in the updated GWP of methane. I’m too tired to chase down exactly how those have changed.
    “Yes, if we assume (as the IPCC and Shindell et. al do) that methane will start to rise again at some assumed value,”
    They do? The IPCC FAR report says, “The reasons for the decrease in the atmospheric CH4 growth rate and the implications for future changes in its
    atmospheric burden are not understood.” It goes on to give some discussion. Methane sources and sinks are not so well understood.
    There is some danger of more methane release with melting permafrost.

  91. carrot eater (21:13:49) :

    If you’re looking for significant change in the numbers, it’s probably in the updated GWP of methane. I’m too tired to chase down exactly how those have changed.
    “Yes, if we assume (as the IPCC and Shindell et. al do) that methane will start to rise again at some assumed value,”
    They do? The IPCC FAR report says, “The reasons for the decrease in the atmospheric CH4 growth rate and the implications for future changes in its atmospheric burden are not understood.” It goes on to give some discussion. Methane sources and sinks are not so well understood.

    The IPCC gives forty different scenarios for the future changes in GHGs. Of these, 36 of them give an estimate of future methane emissions.
    In each and every one of these 36 scenarios, methane is shown as increasing starting now. In some of them the emissions continue to rise through 2100, in some of them the rise peaks somewhere between 2040 and 2080.
    But in all of them it is shown as rising. So yes, the IPCC does assume that methane will start to rise again, as I stated.
    w.

  92. I am happy, the issue could be resolved. Thanks for carrot eater and marcus to further the argument, and especially for marcus, to provide the finally convincing citation.
    By the way, “Marcus (16:49:53) : I also apologize for spelling Zimmermann’s name wrong.” No sweat. Having lived a year in the USA, I know how confusing the German spelling is. The really amazing thing is, what can happen to my first name. 🙂

  93. “As a result, any honest scientist would have to say that we don’t have a clue what methane levels will be a century from now.
    Yes, if we assume (as the IPCC and Shindell et. al do) that methane will start to rise again at some assumed value, it could make a difference. If their model is correct. And if methane levels rise. And if GHG forcing is the secret global thermostat.”
    Shindell’s paper does not actually make any assumptions about the future path of methane growth. The way he calculates a GWP is to assume that we are at an equilibrium methane concentration, and then calculates the radiative forcing (not global temperature) perturbation resulting from emission of an additional ton of methane. This is also how the IPCC calculates GWPs. GWPs are the measure of radiative forcing of a substance relative to that of CO2. The key quote from the paper, as it relates to methane: “The 100-year GWP for methane is ~10% greater (~20 to 40%, including AIE) than earlier estimates (5)”.
    I grant you that the IPCC scenarios almost entirely consist of rising methane concentrations. That is a separate discussion, and one that is likely to be revisited in AR5. I will note that the uncertainty there comes less from uncertainty about the chemistry and more from the uncertainty about trying to measure area sources of methane (rice paddies, swamps, etc.) and therefore get an accurate inventory of anthropogenic vs. natural emissions. I will also note that there has actually been a significant amount of methane emission reductions in the U.S., Europe, and Russia, through some combination of landfill capping, reduced gas infrastructure leakage, and better flaring of fugitive emissions. Therefore, to some extent the lower-than-expected methane growth may be, in part, a result of actual environmental policy. (to some extent it is understood natural variation – rainfall and wildfires and such interacting with methane sources, and to some extent it really is unexplained)

  94. Willis, I follow you now. Well, the B1 scenarios result in little increase in the methane concentration, I think. The newish MFR scenario, which may not be in your SRES tables, has lower methane emissions than the others, though it has low emissions for other things as well. But I agree, we should all be watching to see if the plateau in methane concentrations continues.
    By the way, to keep things clear, you should be careful with methane ‘concentrations’ and ’emissions’. I see when you point out the concentrations above, you said emissions. After all, the Shindell paper underscores the importance of keeping the two straight.

  95. Willis, will you edit the original article to reflect the subsequent discussion? I sometimes refer back to older articles on WUWT, and I assume others do, too. It saves a lot of time if discussion-based corrections are folded back into the original story.

  96. Gary Hladik (12:38:57) :

    Willis, will you edit the original article to reflect the subsequent discussion? I sometimes refer back to older articles on WUWT, and I assume others do, too. It saves a lot of time if discussion-based corrections are folded back into the original story.

    I’m just a guest contributor, I can’t edit it. I’ll ask Anthony to pull it, as the original premise has been shown to be false.

  97. ***********
    Willis Eschenbach (20:17:18) :
    After rising for a number of years, the atmospheric methane emissions have levelled off during the last decade. Nobody knows why this has happened. Heck, nobody knows why they were rising prior to levelling off. Nobody knows which way they will go from here.
    *****************
    I remember from organic chemistry that UV light can break the C-H bond to form free radicals which are very reactive. Solar UV output has been going up. I wonder if that could account for the decrease in methane?
    Solar UV
    http://www.john-daly.com/hockey/solar.gif

  98. Willis Eschenbach (14:27:54):
    Thanks, Willis. Though the premise of the article was incorrect, and the original paper’s contribution “incremental”, the topic is a useful reminder of the complex chemical processes going on in our atmosphere.
    In other words, “It’s more complicated than I thought!” 🙂

  99. **************
    Jim (15:40:23) :
    I remember from organic chemistry that UV light can break the C-H bond to form free radicals which are very reactive. Solar UV output has been going up. I wonder if that could account for the decrease in methane?
    *****************
    Correction, I was remembering the UV initiated reaction between chlorine and methane. The UV breaks the chlorine into two free radicals which then react with methane.

Comments are closed.