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nealjking at 11:32 AM on 2 April 2013Making Sense of Sensitivity … and Keeping It in Perspective
As mentioned before: If there is a flat absorption coefficient across the spectrum, the discussion provided before gives the same result for zero-feedback temperature change as differentiating the S-B.
Not otherwise.
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scaddenp at 10:25 AM on 2 April 2013The Scientific Method
Ray - first, show me any science that uses the term CAGW. This is strawman material.
Continuing, the scientists mentioned are indeed climate scientists who have created true scientific discussion in the correct way - by publishing paper in which their methods etc. have been available for examination. The scientific method has kicked in and tested these ideas against experiement - and tossed them all out. "A" for effort, but still no other hypotheses in the air at the moment. I applaud the effort in one sense because, although motivated by ideology (eg see Spencer on what he thinks his role is) rather than the scientific quest, science depends vitally on a constant search for alternative hypotheses. This is doing it right.
Doing it wrong is saying one thing to your peers and another to the naive (public, congress); and pushing misrepresentations of science of political objectives (noting that environmentalists can be guilty of this too). In my opinion, doing it wrong it also trying make reality conform to your political prejudices but I think the scientific method and publication conventions are robust enough to filter out any poor science resulting from such an approach.
Hansen and the others change models as data and methods improve as indeed they must. Compare say Mann 98 with say Mann 2003. You want others? Idealogues dont change at all. All of your list fortunately agree on all the basic climate theory. They have however, all tried valiantly to find something else in the climate system that might give a low enough value for climate sensitivity so that action to mitigate isnt necessary. I wish they would put some of that energy into finding effective mitigation measures that is compatible with their political philosphy instead.
So are you looking for a good theory which accounts for climate - or an excuse to discount current theory because mitigation actions proposed so far are discordant with your politics? If the former, then perhaps take your specific questions about attribution of climate change to the appropriate topics here (use the search tool).
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Kevin C at 07:55 AM on 2 April 2013Book review: Cold Cash, Cool Climate by Jonathan Koomey
Kevin:
So the author wants us to trust the experts only. But Feynman says to trust the experiments, and that experts can be wrong.
Kevin C has pointed out that even peer reviewed papers can be wrong, and not withdrawn.
There are two pretty fundamental points here. Let's start with the last one and work back.
It is a common mistake of readers here, and sometimes even authors, to assume that because something is in the peer-reviewed literature it is right. That is clearly false. Just count the proportion of scientific papers (in any field) which are disagreeing with a previous paper and you can see that actually a significant proportion of peer-reviewed papers (in any field) must be wrong.
The distinctive feature of the peer-reviewed literature is that by publishing in the peer-reviewed literature you are taking part in a social interaction which has evolved to select good information from bad. Not primarily at the review stage (which is just an initial junk filter), but in the long term response to a paper, which is crudely measured by citations and more accurately by review papers and consensus. (Hence my arugment that we need sociology as well as philosophy of science.)
Therefore, if someone cites the existance a peer-reviewed paper on either side of the argument as settling an issue, you are right to call them on it. So papers on their own don't settle issues. However, Feynman is no help either, because most of the systems we are interested in are sufficiently complex than any experimental result requires interpretation within the framework of thousands of other results, which are usually more conveniently summarised in terms of theories. To work from experiments alone requires you to rediscover modern science from scratch.
So either you need to study the literature sufficiently to be able to form a clear picture of the shape of the field, the areas where multiple lines of evidence agree and those where they disagree, the robustness of different observations, the potential confounding factors, and the diversity of opinion and its evolution over time. Something which in my own field took me (I guess) a decade of full time effort, although the process has continued since.
In other words, the development of expertise. So either you need to become an expert, or trust an expert. Now of course anyone can claim to be an expert without putting in the effort to obtain that expertise. So how are we to tell a real expert from a fake one? The most effective method to have evolved so far is on the basis of contribution to the field.
This is the same for every field of science. Journals are edited by and grants are awarded by panels recuited from the most prominent contributors to a field. This works because scientists tend to think rather highly of their own ability, are mostly in pretty rigorous competition with one another, and are therefore more than willing to demolish one-anothers work if it has weaknesses. Again, this is true in every field. If you want evidence that the same is true in climate science, read the climategate emails.
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Chris Colose at 07:19 AM on 2 April 2013Making Sense of Sensitivity … and Keeping It in Perspective
Since I was e-mailed about this, I'll chime in...
It doesn't matter what you define as the "no feedback climate sensitivity." Obviously, dT = dF/(4 σT^3) ...(or dF = 4σT^3 dT) is a natural reference system derived directly from the Planck law, and because there's very little uncertaintly in how to calculate it, it has traditionally been used as a reference system by which other feedbacks are evaluated against. In a climate model, this would be derived by perturbing the atmospheric temperature by, say, 1 K, and holding other variables constant (water vapor, etc) and then asking how much the infrared emission to space has increased (see e.g., Table 1 in Soden et al., 2006, "An Assessment of Climate Feedbacks in Coupled Ocean–Atmosphere Models"). The results are very close to the back-of-envelope calculation shown above.
In the real world of course, water vapor makes the infrared emission increase more slowly than the Stefan-Boltzmann law, so a greater temperature rise is required to accomodate the need to balance energy at the top of the atmosphere. If the system were dominated by negative feedbacks, then the flux adjustment would be more efficient than T^4, and you wouldn't need much temperature rise to balance the incoming sunlight.
If you wanted, you could just as well call your reference system one in which relative humidity stayed the same. This would make the "no feedback climate sensitivity" appear much larger, but then reduce the magnitude of feedbacks, since the water vapor feedback would now only consist of a small residual that resulted from any departures in the relative humidity field. In the same way, the Stefan-Boltzmann law is not an adequte description of radiative transfer in a real atmosphere, yet still provides a convenient baseline which allows us to talk about 'feedbacks' in a meaningful way. It doesn't hurt the calculation too much that you have absorption to worry about, since "T" is evaluated at the top of the atmosphere and you need to eventually balance the fluxes regardless of what wavelength region they occur in. -
jgkoomey at 06:34 AM on 2 April 2013Book review: Cold Cash, Cool Climate by Jonathan Koomey
@Kevin: @shoyemore has given an excellent response, but I wanted to describe my own views on this. I'm the last person to unquestioningly adhere to the statements of any authority, and I'm all for questioning conclusions of all types, if that questioning is done in an informed manner. The technique I describe is meant to get people to think about why they think questioning climate science is OK when they don't know the first thing about the topic. I vividly recall a video in which a questioner in Australia tried to lecture my friend Stephen Schneider about how climate forcings were logarithmic and that this somehow invalidated the whole of climate science (wrong on multiple levels, and Stephen put the questioner in her place). The questioner would never have done this for a physicist lecturing on gravity, and I want to get people to think about why they think climate change is any different. From the perspective of a lay person, it isn't much different--there is extensive peer review, and errors are uncovered and corrected over time, just like for all other science. The incentives are the same as for other areas of science as well, so if they trust that science and related engineering (and they largely should, since it allows technological devices and systems to operate correctly) then they should trust the climate science also.
Of course, nothing will get in the way of a hard core denier believing what they want to believe, but we all need to find new and different ways to get the people who are "reachable" to rethink their beliefs. This technique has worked well for me in my lectures, but something different might work better for you. No one approach will work for all audiences, of course.
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KenD at 05:31 AM on 2 April 2013It's not bad
Thanks, Bob and Bernard. Bob, I looked through some of the Arrhenius article, but I confess I'm not technical enough to home in on the best example of a prediction he made that has since come true. Bernard, if you were to place a bet on the minimum volume of Artic sea ice by 2023 (assuming C02 levels remain at or above current levels), what value you would bet on, assuming you want to keep your money safe?
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Phil at 05:24 AM on 2 April 2013Making Sense of Sensitivity … and Keeping It in Perspective
re: Pressure broadening.
A vibrational absorbtion has breadth because the rotational energy quanta differ in the ground and 1st levels of the vibration. Because of this difference transitions between the different rotational levels "fan out". This "fine structure" thus has tiny windows within the band through which radiation can pass (if its of the correct frequency of course!). Pressure broadens the individual rotational fine structure of the vibration thus reducing the size of these windows. Since the rotation of molecules depends on the mass of the nuclei, isotopes cause two sligtly different spectra to be overlaid;
Other things can affect the width of these bands; nuclear spin of the nuclei in the molecule is significant, especially for molecules containing Hydrogen. The other effect that may be significant is complexation - spectral absorbtion due to entities such as (CO2...H2O). These have vibrational frequencies similar to the lone molecule (and some extra) but significantly different rotational characteristics, which would make their spectra less window like. These entities were the subject of my Ph.D, and we occassionally speculated whether they played a significant effect in the greenhouse effect. To my (somewhat outdated) knowledge this question has not been answered.
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Paul D at 03:45 AM on 2 April 2013The Scientific Method
John Russel "Global climate models are not, as you so accusingly describe them, "to prove the hypothesis of AGW ". They were firstly created to enable meteorologists to provide more accurate weather forecasts."
A 5 fold improvement in the case of the UK, Met Office. -
shoyemore at 03:45 AM on 2 April 2013Book review: Cold Cash, Cool Climate by Jonathan Koomey
Kevin,
The obvious question is "Who is an expert?". We accept advice from range of "experts" all the time, in fields where we have reduced competence - doctors, lawyers, car mechanics, plumbers, dieticians, gym coaches, tax accountants, counsellors, ...
If we apply Feynman's principle across the board, and eschew consultation with any expert, it actually makes modern life impossible. You might prefer to put Feynman's quotation in some context.
https://sphaerica.wordpress.com/2010/08/07/the-ignorance-of-experts/
The way I suggest to get around Feynman is of course to build up a "jury" of trusted experts. In his book Nonsense on Stilts (reccommended), philosopher and scientist Massimo Piglucci suggests criteria for experts:
- Examine the experts arguments logically
- Is there agreement with other experts ?
- Is there independent evidence of expertise (qualifications)?
- Examine possible biases.
- What is the track record of the expert?
This is as simple as getting a second opinion from a doctor or a mechanic. One, of course, one must still Trust, but Verify!, and there is no guarantee of error in a particular case.
The above list is an expansion of Koomey's question.
It is also disappointing to see Richard Feynman elevated to the level of infallible sage, a role he would have abhorred. We are as entitled to be as sceptical about Feynman's nostrums as about anyone's.
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barry1487 at 03:33 AM on 2 April 2013Making Sense of Sensitivity … and Keeping It in Perspective
Thanks again, nealjking.
"Chris Colose originally mentioned the pressure broadening to me, and he claimed it would slightly increase the overall probability of absorption. It would take a little reading to sort this question out."
I went for a casual trawl and found another realclimate article;
...Molecules composed of three or more atoms tend to act as greenhouse gases because they can possess energy in terms of rotation and vibrations which can be associated with the energy of photons at the infra-red range. This can be explained by theory and be demonstrated in lab experiments. Other effects are present too, such as pressure and Doppler broadening, however, these are secondary effects in this story.
http://www.realclimate.org/index.php/archives/2010/07/a-simple-recipe-for-ghe/
There they link to the following paper, which, if you have access, might interest you.
A precise measurement of the vertical profiles of carbon dioxide is required for reducing the uncertainty in the carbon budget. In order to achieve measurements of the vertical CO2 distribution with an uncertainty better than approximately 4 ppm, a precise knowledge of the pressure-dependent broadening and shift coefficients of CO2 absorption lines is indispensable.
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BillEverett at 03:16 AM on 2 April 2013The Scientific Method
A brief comment on models in relation to the scientific method. First, there are big theories with names, etc., and there are little theories. Each theory is an expression of our understanding of how a part of the observable "real" world works. Big theories explain a reasonably large part; small theories explain a small part. Hypotheses or conjectures are "reasonable" proposed amendments to a theory.
A theory can be stated in words. A theory stated only in words is rather imprecise and open to multiple interpretations. A better statement of a theory is a mathematical equation (or system of equations) relating quantities representing measurable aspects (observables) of the world. Some equations are exactly solvable (analytically). Many equations are not exactly solvable. Many different techniques of numerical analysis have been developed (and are currently being developed) to deal with equations that are not exactly solvable. The large majority of contemporary numerical methods involve "computer simulation" approaches, and there are many different computer simulation techniques. (All the preceding statements about equations apply equally to systems of equations.) Hard science is not interested in imprecise theories that are open to multiple interpretations. Hard science is interested in precisely stated unambiguous theories, which means mathematical equations relating quantities that represent observables.
In this context, "theory" and "model" are essentially synonyms. The theory (model) is not the words we use to discuss or describe it. The theory (model) is the equations and the operational definitions of the measurable quantities involved in those equations.
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shoyemore at 02:57 AM on 2 April 2013The Scientific Method
Kevin #31,
Ray did not say "surface warming". He said "climate change", and climate can be influenced in many directions when it comes to a range of phenomena.
Phil's chart (#37) shows that climate change is a multi-factor process, of which the human contribution is only one.
Ray was unaware of this, exposing his lack of understanding ... a strange lack for a scientist who (one would have expected) have examined the evidence for what he was propounding.
Phil actually summarises it very well. Human factors may dominate (that is the claim Ray should have been discussing), but there are other influences.
Moderator Response:[RH] All further discussion of "human contribution" needs to be taken to a more appropriate thread.
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MA Rodger at 02:25 AM on 2 April 2013Making Sense of Sensitivity … and Keeping It in Perspective
nealjking @88
It is entirely evident from your comment @76, @78 & @88 that the position you took @67 & @70 refers solely to the evaluation of forcing ΔF. I have not been at any time suggesting that Stephan-Boltzmann is so used, proposing rather that it is applicable (and indeed I have show it has been applied) to calculate zero-feedback-sensitivity λo.
So I shall end this interchange here although I shall be now to enquiing elsewhere as to the nature of those "models" reportedly used to calculate λo and report back if I glean any findings. -
barry1487 at 02:21 AM on 2 April 2013The Scientific Method
I kind of get what CN is saying. We have no 'need' to work out how the universe began, nor is the the matter a 'problem' that requires us to solve it. We ask because we are curious.
1. Define a question that may be answered analytically.
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Bob Lacatena at 02:00 AM on 2 April 2013The Scientific Method
Climate Newbie, 40,
I'm not saying you're wrong, but I think you're being a bit pedantic. So if we rephrase it are you happier?
- Define a question that needs an answer;
- Formulate an explanation for the situation;
- Determine or deduce a prediction based on the explanation;
- Perform tests or experiments to see if the explanation is valid.
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Kevin8233 at 01:56 AM on 2 April 2013Book review: Cold Cash, Cool Climate by Jonathan Koomey
Koomey also suggests a higher-level approach that he’s found particularly effective:
If you hear someone using such talking points, try asking the speaker these questions: “Do you feel qualified to judge the current findings of the science on combustion, or gravity, or quantum physics? No? Why then do you opine on a topic that is equally complex but upon which you have no more mastery? Why do you think your judgment on these complex issues is the equal of that of people who have studied the topic for decades?”
Typically the speaker will reply with some statement of authority, like “I’ve studied engineering for years”, or “I’m a weather forecaster”, or “my uncle Joe the physicist said so”. Such responses are beside the point. Unless the speaker is an expert in the field, their opinions should be given no more weight than any other uninformed observer. Would you ask your allergist about the heart surgery your cardiologist recommends?
Given the above advice, it is difficult to reconcile with other quotes found on this site;
"In general we look for a new law by the following process. First we guess it. Then we compute the consequences of the guess to see what would be implied if this law that we guessed is right. Then we compare the result of the computation to nature, with experiment or experience, compare it directly with observation, to see if it works. If it disagrees with experiment it is wrong. In that simple statement is the key to science. It does not make any difference how beautiful your guess is. It does not make any difference how smart you are, who made the guess, or what his name is – if it disagrees with experiment it is wrong. That is all there is to it." Richard Feynman
or
Science is the belief in the ignorance of experts. - Richard Feynman
or
Kevin C at 00:44 AM on 23 March, 2013
If it does not have the same title (or has revisions), then presumably the recursive fury paper will need to be withdrawn?
Papers are not retracted for requiring minor clarifications, or even for being subsequently shown to be completely wrong. Papers are retracted for serious misconduct or fraud.
So the author wants us to trust the experts only. But Feynman says to trust the experiments, and that experts can be wrong.
Kevin C has pointed out that even peer reviewed papers can be wrong, and not withdrawn.
So obviously, the answer is not that simple.
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Bob Lacatena at 01:51 AM on 2 April 2013The Scientific Method
Climate Newbie, 37,
Many people misapply that Feynman quote. You might want to look at what I wrote about it a few years ago (after taking the time to put the quote into context by reading the entire speech from which it came, and recognizing the audience and goal of that speech).
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Climate Newbie at 01:45 AM on 2 April 2013The Scientific Method
My own point of view is that the four step process outlined above is a better definition of engineering than science. My main beef is with the first step. Science is not about solving problems, it is about answering questions. When one presumes the existence of a problem, there is already an inherent bias toward prescibing a solution. Real science must start with the pursuit of knowledge for its own sake. If that knowledge identifies problems, and possible solutions, that's wonderful, but that is not the essence of science.
Moderator Response: [JH] Your prior post was deleted because you provided no context for your quote. -
KR at 01:44 AM on 2 April 2013The Scientific Method
Climate Newbie - "...if it disagrees with experiment it is wrong"
Indeed. With that in mind, it's interesting to see how 'skeptic' predictions fare against the IPCC (skeptic predictions fare poorly). Raymond Pierrehumbert discusses some successful predictions here, and there's an interesting overview of successful climate model predictions - dating back to Arrhenius. Not to mention that has theory has repeatedly proved out over initial (incorrect) measures such as the UAH temperatures.
'Skeptic' predictions, whether of temperature, Arctic ice, or pretty much anything else? They don't fare very well against the data; they are (so far, at least) wrong.
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Climate Newbie at 01:05 AM on 2 April 2013The Scientific Method
Science is the belief in the ignorance of experts. - Richard Feynman
Moderator Response: [JH} Posting quotes without providing context is skating on the thin ice of sloganeering. Please cease and desist. -
Climate Newbie at 01:02 AM on 2 April 2013The Scientific Method
[Science] is not perfect. It can be misused. It is only a tool. But it is by far the best tool we have, self-correcting, ongoing, applicable to everything. It has two rules. First: there are no sacred truths; all assumptions must be critically examined; arguments from authority are worthless. Second: whatever is inconsistent with the facts must be discarded or revised. ... The obvious is sometimes false; the unexpected is sometimes true.
— Carl Sagan -
nealjking at 00:58 AM on 2 April 2013Making Sense of Sensitivity … and Keeping It in Perspective
MA Rodger:
The fact that a back-of-the-envelope calculation happens to roughly match another roughly defined quantity does not give a good basis for concluding that that calculation is a valid explanation for the quantity. The linkage has to be shown by the relevant physics, some portion of which I have explained.
Based on what has already been discussed, the formula would match if:
- The entire infrared spectrum were covered by GHG bands (which it is NOT); AND
- The absorption coefficient were a constant function over that range (which it is also NOT).
Since in actual fact, neither are true, there is no applicability of this "derivation" to the EGHE. Don't fall into the freshman's fallacy of finding just some random formula that happens to give the right answer for some lucky combination and assuming that this explains the physics. It doesn't.
If you really want to understand what is going on in a fairly complicated problem like this, you're better off looking to see what people have done, rather than cooking your own explanation. Riccardo's article referenced in #85 would be a good starting point. Beyond that, I have mentioned books by Houghton, Pierrehumbert; and there is probably a paper in Archer's collection of "warming papers". Try looking for these sources before rolling your own. My impression is that the formula didn't get general agreement untiil the 1960's or so; about 100 years after the GHE was conceived. Why do you think the explanation is going to be as simple as that?
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Phil at 00:10 AM on 2 April 2013The Scientific Method
The image below is taken from the SKS article Kevin quotes, and clearly show both natural and anthropogenic contributions to global warming.
Ray's point
I... have yet to be convinced that climate change is caused only by humans.
Is clearly valid when talking about climate change in general, but incorrect when talking about the specific instance of the climate change that is happening now, where have anthropogenic contributions have been shown to predominmate.
Moderator Response: [RH] Fixed image width. -
Tom Curtis at 23:59 PM on 1 April 2013The Scientific Method
Ray @27, I don't think it is fair to Lakatos to say that is work "followed on" from Kuhn. It would be better to say that it "followed on" from Popper (whose student Lakatos was), differing from Popper almost exclusively in properly accounting for the Duhem-Quine thesis. Despite that, both Kuhn and Lakatos recognized the remarkable similarities of their theories. Indeed, both agreed that where it not for one issue, they would be essentially the same theory. That issue was "incomensurability", Kuhn's thesis that paradigms could not be understood from within the framework of competing paradigms. Lakatos rightly rejected that thesis as irrational, and clearly false.
The problem is, it is that thesis, and only that thesis that you appear to have drawn from Kuhn. You have flushed away all that is valuable in Kuhn, and retained only the dross. The simple fact is that if "paradigms"/"scientific research programs" are not incomesurable (as Kuhn would have it), then an acceptor of one paradigm can recognize what is valuable and what is dross in another paradigm. Given that, while there may be biases against unpopular or improbable theories, these biases will be a consequence of the fact that scientists are human and have human emotions. They will not be systemic, and they will not preclude original or valuable advances with any merit.
Indeed, the history of climate science shows that climate scientists are willing to try any theory that shows minimum plausibility. The extent of funding for research into Svenmarks theory of climate modulation by cosmic rays shows climate scientists do not, in general, supress rival theories.
Unfortunately the authors of those rival theories are not so generous. They appear to want their theories to be accepted without first meeting the tedious requirement of empirical confirmation that has been met by the standard theory. Indeed, the only epistomological bar placed on alternate theories is not empirical success, but only that it be "anything but CO2".
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MA Rodger at 23:46 PM on 1 April 2013Making Sense of Sensitivity … and Keeping It in Perspective
nealjking @78.
I shall be less cryptic than @77.
The forcing ΔF resulting from ΔCO2 is not at issue. As TAR describes this relationship can be presented usefully in its simplest form thus:-
ΔF = 5.35 In(C/Co) W/sq m
The issue at hand concerns only the global temperature change ΔT resulting from ΔF and specifically that change when feedbacks are zero. I have no definitive reference to state what method is used within climatology to calculate that value. Yet they do calculate it and do so with far more precision than ΔT with all feedbacks (as the relative imprecision of ECS estimates shows).
So what is that method?
(a) It is a "relatively straightforward" calculation according to AR4 so we seek nothing fancy.
(b) It yields a number "1.2°C (with an accuracy of ±10%)" (although that is for 4 Wm^-2) according to TAR.
(c) I recall from years ago many references saying it was calculated using the Stephan-Boltzmann equation but today I see nothing definitive to point you at.
(d) I do not recall seeing any alternative method for this calculation.
(e) And (bar internet searches topping out with a denialist force →100% Watts/sq page) I do find climatologists saying Stephan-Bortzmann provides a zero-feedback ΔT, eg Roe & Baker using it to calculate zero-feedback-sensitivity λo. Particulalry note Chris Colose posting at RealClimate who describes such a use of Stephan-Boltzmann as a 'back-of-envelope calculating' yielding λo=0.27°C/Wm^-2 while models yield λo=0.30-0.31°C/Wm^-2 or "about ~1.2°C" for double CO2.
Thus I can but conclude that Stephan-Boltzmann is applicable in the context of the enhanced greenhouse effect. And that it does yield a reasonable answer (ie. of 'about 1°C' which is what is commonly quoted). And while "models" are used to improve accuracy, Stephan-Boltzmann does a pretty good job without recourse to those "models" which is so often the point of departure for folk of a denialist disposition, this last point being why the methods used should perhaps be better known.
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Bob Lacatena at 23:35 PM on 1 April 2013The Scientific Method
Ray,
I... have yet to be convinced that climate change is caused only by humans.
What evidence have you seen that it is?
What evidence have you seen that it is not?To what does the application of the scientific method point?
[There is a wealth of evidence available, in a variety of forms. At this point in time, there is no reason for there to be any doubt in this matter.]
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Ray at 23:30 PM on 1 April 2013The Scientific Method
Thanks very much for your information Kevin which certainly fills in gaps in my knowledge and it would seem, may provide information of which shoyemore was also unaware
Moderator Response:[DB] "may provide information of which shoyemore was also unaware"
Please cease with the strawman argumentation. This venue is not about scoring rhetorical points. Shoyemore's point
a claim was made that climate change was caused solely by humans
is not the same as
ghg are responsible for between 100% and 200% of surface warming
Shoyemore is certainly aware of the difference, as are the vast majority of the participants in this venue.
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Kevin8233 at 23:13 PM on 1 April 2013The Scientific Method
shoyemore,
Over the past 60 years (1951–2010), the study finds that global average surface temperatures have warmed 0.6°C, while in climate models, greenhouse gases caused between 0.6 and 1.2°C surface warming. This was offset by a cooling from other human influences (mainly from aerosols) of 0 to 0.5°C. These results are consistent with all prior studies of the causes of global warming (Figure 1).
Figure 1: Net human and natural percent contributions to the observed global surface warming over the past 50-65 years according to Tett et al. 2000 (T00, dark blue), Meehl et al. 2004 (M04, red), Stone et al. 2007 (S07, light green), Lean and Rind 2008 (LR08, purple), Huber and Knutti 2011 (HK11, light blue), Gillett et al. 2012 (G12, orange), Wigley and Santer 2012 (WS12, dark green), and Jones et al. 2013 (J12, pink).
This is a quote from the "New study - Same result" posting here on SkS. In this posting, "Humans" by causing the increase in ghg are responsible for between 100% and 200% of surface warming.
I believe this satisfies your demand of Ray.
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nealjking at 23:13 PM on 1 April 2013Making Sense of Sensitivity … and Keeping It in Perspective
Tom Dayton:
Thanks for pointing out the article on CO2 saturation: I have wondered where that article was hiding.
Actually, my understanding of how the various aspects of line broadening affect the absorption coefficient is a current weak point in how I think about the GHE, so it would require some more study to pin it down better than what Riccardo has already written.
Maybe later.
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shoyemore at 22:55 PM on 1 April 2013The Scientific Method
RAy,
I think you need to show us where a claim was made that climate change was caused solely by humans. There is none on this site AFAIK and none in the scientific literature I ever heard of.
You clearly have a lot of reading to do.
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Tom Dayton at 22:53 PM on 1 April 2013Making Sense of Sensitivity … and Keeping It in Perspective
Neal, maybe your explanation of broadening could be added as a section in the Advanced tab of "Is the CO2 Effect Saturated?"
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nealjking at 22:30 PM on 1 April 2013Making Sense of Sensitivity … and Keeping It in Perspective
barry:
The pressure broadening affects the absorption coefficient:
- In a thin gas, the absorption coefficient is derived by doing the quantum mechanical calculation for the absorption probability of a photon by a single atom; and then multiplying it by the number density of that type of atom.
- The result is a function of frequency, with lots of regions of nothing and occasional blips where the frequency matches a quantum transition. The height of a peak is related to the likelihood of absorbing a photon in that region; the width is inversely related to the rapidity with which this transition will occur. Thus, the longer the lifetime of the state (before transition), the narrower the width.
- The resulting absorption coefficient is what is integrated along the optical path of the radiation beam to calculate the optical depth. The significance of the optical depth is: If a photon travels along the beam for an optical depth of magnitude 1, that means it has a probability of (1 - 1/e ) of surviving that trip without having been absorbed. So a photon emitted towards space at an optical depth less than 1(as measured from outer space inward) has a decent chance of actually escaping the atmosphere without being absorbed; whereas a lower-altitude photon headed up will most likely be stopped along the way; it's energy will eventually be emitted as a new photon.
- In a thicker gas, the picture is modified a little: The atoms of interest will be suffering collisions with the other atoms (of the same type or not, I don't believe it matters). The result is that the lifetime of the pre-transition state is shortened, because the atomic state can be changed without absorbing the photon. I believe this has the following effects on the absorption peak:
a) broadens it, so the frequencies of interest are a wider subband; b) lowers the peak; c) reduces to some extent the total probability of absorption (but I don't know if this is at all significant; and there might be a countervailing factor).- So the effect of the pressure broadening is to flatten and spread out the absorption peaks in the absorption coefficient curves. Otherwise, these curves are used just as before to calculate the altitudes of the OD=1 points, as a function of frequency.
[Now that we discuss this in detail, I wonder if there could be a reduction in the frequency integral of the absorption curve due to pressure broadening. It should be noted that there are other contributors to spectral-line broadening, like Doppler shifting due to the random kinetic motion of the molecules. Chris Colose originally mentioned the pressure broadening to me, and he claimed it would slightly increase the overall probability of absorption. It would take a little reading to sort this question out.]
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Tom Dayton at 22:22 PM on 1 April 2013The Scientific Method
Feyerabend was correct in many points, about the messiness of how science really is and should be done. You need not buy into his fully anarchistic view, to appreciate the truth of many of his points.
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Ray at 22:15 PM on 1 April 2013The Scientific Method
Shoyemore. I think debate is very stimulating ndf very useful but think you have misunderstood what I stated so perhaps I didn't state it clearly enough. You say "It is also a strange attitude from a scientist to say that you "don't believe in climate change" and invite others to supply you with "evidence". Surely as a scientist you should check the evidence BEFORE you make decisions about your beliefs, I did not I didn't believe in climate change but on rereading I can see why you thought I did as I phrased it poorly by saying " And fiinally there are very few scientists including me, that don't believe in climate change." To make it perfectly clear I do believe in climate change but have yet to be convinced that climate change is caused only by humans. But I have to apologise for some very poor phrasing which has created a false impression of my stancer om this topic
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shoyemore at 21:36 PM on 1 April 2013The Scientific Method
Ray,
You are very adept at rounding up the usual suspects.
Firstly, the group of climate scientists you name are one of the few groups you could possibly name in the category, whereas I could name hundreds of groups of four or five scientists who would not see eye to eye. One you get past the Heartland Institute annual jamboree of "climate science", you are at a loss. How about Prof Scott Denning, Prof Richard Alley, Dr Ben Santer and Professor Veerabhadran Ramanathan? Kindly enumerate where their "predictions" did not meet your standards.
Secondly, what is your judgment on Dr Roy Spencer's many predictions of imminent cooling, and arctic ice recovery? Does this not suggest his "alternative theory" (if he has one) is falsified. You might care to read some of the slip-ups of climate misinformers by clicking the link on the top left of the page.
I have been trying to emphasise the collegiality of science and its powers of self-correction. I would put by faith in the science as a whole, and not in your "Gang of Five".
You seem uninterested in checking out the assumptions Dr Hansen made in his 1988 paper, despite being supplied with the means to do so. A strange reaction for a scientist.
It is also a strange attitude from a scientist to say that you "don't believe in climate change" and invite others to supply you with "evidence". Surely as a scientist you should check the evidence BEFORE you make decisions about your beliefs, expecially when it contradicts your prior assumptions. I expected you to be as familiar with the evidence as anyone else on the site.
There is evidence out there (a lot of it on this site, if you could rise to checking it out) but few of us are in the business of making up the deficiencies of the intellectually slothful or the closed-minded.
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shoyemore at 21:14 PM on 1 April 2013The Scientific Method
BillEverett @23
Denial fails at 1) because they rarely come forward with alternative hypotheses. Platt's procedure seems to me to be fair enough, but many of these procedures miss out on the "hidden hand" of science - there is a big dependence on replication by more than one experimental group, groups which are often fierce rivals, as much as commercial organisations are rivals.
Science does keep itself honest and self-correcting, though sometimes notorious cases slip through.
My opinion is that long-standing scientific theories are rarely simple enough to stand or fall on a single experiment. A great example is the "neutrinos-faster-than-light" controversy of last year. First of all, no one got over-excited, awaiting replication of the results. Secondly, no one suggested abandoning Einstein's major axiom overnight. Short-cuts through higher-dimensions and other contrivances were suggested to "save the theory". In the end, it turned out to be error in the apparatus.
A Richrd Feynman anecdote tells the same story. Feynman and Gell-Mann put forward a new theory of beta decay. They published and 6 months later, the first experimental test results came in - the theory failed.
Gell-Mann said to Feynmann: "What do we do now?"
Feynman shrugged. "We wait" was all he said.
Another few months, and more results came in - the experimenter admitted a technical hitch, and the new results were confirmatory. it all tends to show that overthrowing a scientific theory is not a simple matter of totting up experimental predictions.
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Ray at 21:01 PM on 1 April 2013The Scientific Method
Thanks for the comments although it appears that you are all focussing on some remarks I made about climate science rather than on the scientific method. Many of the comments I made on the scientific method including the "blinkered" comment were first enunciated by Kuhn whose work, incidentally, formed the basis of the subsequent work by Lakatos referred to by others But to revert to the areas that appear to have ignited passions. (-snip-). And fiinally there are very few scientists including me, that don't believe in climate change. That said however, so far as I am aware there has been no direct observational or experimental studies that conclusively that global warming is primarily due to human production of CO2. If there are such studies I would be very grateful for links to them as it is apparent such studies will be very relevant to this discussion of the scientific method
Moderator Response: [DB] Off-topic snipped. -
shoyemore at 20:58 PM on 1 April 2013The Scientific Method
chriskoz @22
Ray is obviously sloganeering as the addition of the C to AGW is always done with pejorative intent. However there is no CAGW theory in the scientific literature so the faux-acronym is out of place in this discussion.
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barry1487 at 20:58 PM on 1 April 2013Making Sense of Sensitivity … and Keeping It in Perspective
Thanks nealjking, that's speaks directly to my question. If you wouldn't mind pointing it out, where above are the equations that account for pressure broadening? I looked up the Beer-Lambert law and wondered if it is included in some form upthread (assuming I'm on the right track - my curiosity far overreaches my ken).
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BillEverett at 19:07 PM on 1 April 2013The Scientific Method
An alternative to the four steps of scientific method listed in the post is the notion of "strong inference" discussed by John R. Platt:
Strong inference consists of applying the following steps to every problem in science, formally and explicitly and regularly:
1) Devising alternative hypotheses;
2) Devising a crucial experiment (or several of them), with alternative possible outcomes, each of which will, as nearly as possible, exclude one or more of the hypotheses;
3) Carrying out the experiment so as to get a clean result;
1') Recycling the procedure, making subhypotheses or sequential hypotheses to refine the possibilities that remain; and so on.
Incidentally, the paper following Platt's paper in Science in 1964 might also have historical interest to some: "Glacier Geophysics" by Barclay Kamb: "Dynamic response of glaciers to changing climate may shed light on processes in the earth's interior."
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chriskoz at 18:47 PM on 1 April 2013The Scientific Method
shoyemor@20,
Although the first hit on google translated said acronym as:
Citizens Against Government Waste
but I also found:
Catastrophic Anthropogenic Global Warming
and that's almost certainly (I guess at least 3sigma) what Ray meant.
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Matt Bennett at 18:40 PM on 1 April 2013The Scientific Method
Sorry Ray, false balance there my friend. Just because you can name three or four contrarian climate scientists (whose opinions are notably fringe in their field) who have at least managed to be published, doesn't mean the other three or four you pluck out of the consensus field should share equal billing with this mob and that'is all there is to it..... Oh no! Have a look at Hansen et al and at their publishing record and their citation indices etc then get back to me. It's like selecting a representative of EACH of the many and varied theories as to who wrote Shakespeare's plays and then chucking a single historian amidst this crowd who believes the evidence suggests that, hey, actually Shakespeare himself wrote them. This is not a fair representation of the 'expert historical opinion' out there and is a very contemporary phenomenon - as I said, false balance. It's the very crime I've been accusing the Murdoch press of above, esp The Oz. -
shoyemore at 18:28 PM on 1 April 2013The Scientific Method
Ray,
Dr Hansen's scenarios are discussed here.
Science is not a game with two teams and "victory" going to the team that "scores" more accurate predictions. It is seldom that simple, and then only with very sketchy theories like caloric, the lumeniferous aether or the Steady State Universe. The last two were demolished by a single set of observations - but a complex set of observations and hypothesis like the Standard Model of Particle Physics could not be overthrown by a single experiment - though it might be modified.
Dr Hansen's paper has to evaluated on the basis of the assumptions made, or the "auxiliary hypotheses" described by Tom Curtis in #7. You will find it emerges as far stronger than you give it credit.
http://www.skepticalscience.com/Hansen-1988-prediction.htm
The outcome is no reason to abandon AGW as a theory.
The failure's of Newton's theory to predict the orbit of Jupiter did not lead to its abandonment - it led to the discovery of Neptune. Newton's theories had made two many successful predictions to be given up lightly. Scientists are instinctively conservative and will not abandon a complex and sussessful scientific theory overnight - indeed Max Planck said they wait until followers of the old theory die out!
PS AGW is a handy shorthand. What is CAGW? C standing for what, exactly?
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Ray at 17:32 PM on 1 April 2013The Scientific Method
I'm sorry scaddenp but having re-read the topic posted I can't quite follow the points you are making. The article under dicusssion is on the scientific method and the comments I make on the scientific method are, as far as I can see, entirely relevant. I presume therefore you are referring to my comment "However in the field of climate science this discussion is severely hampered by the entrenched positions on both sides of the debate." Is this inaccurate? There are discussions on climate science between Dr Pielke Snr, Dr Pielke Jnr, Dr Roy Spencer, Dr John Christie and Dr Judith Curry who have some reservations about CAGW and Dr Gavin Schmidt, Dr Phil Jones, Dr Michael Mann, Dr Kevin Trenberth and Dr Eric Steig who have few reservations about of CAGW. All of these are clmate scientists and it his hard to see how Drs. Christy, Spencer, Curry et al fall into your category "However, the "discussion" is between non-climate scientists, (ideologically-driven for most part), trying to fool the public with misinformation;. Similarly I wonder if Drs. Schmidt, Jones, Mann et all would be flattered by your comment "real scientists who on the whole are inept in public communication." All of these scientists publish and comment on the publications of others which seems to cover your point that " If there was real debate, then it would be reflected in the exchange in scientific papers." It is my opinion that there are entrenched positions but I accept that you don't consider this to be the case. I respect yoiur opinion. (-snip-).
Moderator Response: [DB] Off-topic snipped. -
Kevin C at 17:16 PM on 1 April 2013The Scientific Method
An article on the scientific method without a mention of Popper is a startling development. However it maybe no bad thing.
Ray brings up Thomas Kuhn, but is already trumped by Tom's Imre Lakatos further up the thread. For anyone wanting to understand how normal science really works I'd definately recommend reading at least as far a Lakatos - in particular the distinction between progressive and degenerate scientific programs is particularly revealing with respect to climate science.
A very brief stufy of the sceptic literature reveals that there is no skeptic scientific program, but merely a collection of inconsistent claims supposedly refuting the consensus program. At the same time there are constant challenges from within the progressive program re-evaluating parts of that program - a hallmark of a progressive program. While the greenhouse effect is clearly a part of that hard core, GCMs clearly aren't, which is where Climate4All misunderstands the shape of the program.
Having said that, I think to fully understand the situation in climate science we need to go beyond Lakatos and understand not just the philosophy but the sociology of science.
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nealjking at 17:15 PM on 1 April 2013Making Sense of Sensitivity … and Keeping It in Perspective
barry:
The basic equations are radiative-transfer equations, that describe how the intensity of a radiation beam changes along its path. These are equations relating integrals of the absorption coefficient, whicih depend on frequency and also on the local pressure because of the pressure broadening. So in principle, the general picture is unchanged, but the real calculations have to be done for one frequency at aa time (line by line). Also, the description in terms of the equation of local radiative spectral density with local gas dynamics is approximate, because there is a "delay".
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Matt Bennett at 16:51 PM on 1 April 2013The Scientific Method
Well put scaddenp. And further to that Ray, if you'd actually done your homework and understood what's known with relative certainty and what remains to be pinned down with better precision, there's no way you'd be so easily mislead into thinking James Hansen had experienced some epiphany whereby he'd changed his thinking in some major way. Keep reading. As scaddenp said, the illusion of some great argument among the true experts is exactly that, a delusion born of ignorance. It is even more telling that you think that this imaginary 'blinkered' scientific thinking is somehow peculiar to climate science, a convenience of politics perhaps? MModerator Response: [DB] Fixed name spelling. -
scaddenp at 16:41 PM on 1 April 2013The Scientific Method
Ray, your comments would make sense if there was some scientific debate actually in progress. However, the "discussion" is between non-climate scientists, (ideologically-driven for most part), trying to fool the public with misinformation; and real scientists who on the whole are inept in public communication. If there was real debate, then it would be reflected in the exchange in scientific papers. There isnt. The "entrenched" position is a preference for reality over distortion.
By all means discussion alternative hypotheses backed by data and published papers but good luck finding them.
Hansen's comments by the way represent no change in climate theory at all - merely a wondering about the actual value of a poorly measured forcing. Not a single equation in climate science is changed.
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barry1487 at 15:14 PM on 1 April 2013The Scientific Method
Would it be worth including the differences between deductive and inductive reasoning in scientific theories? The notion of 'proof' is often misapplied.
Moderator Response:In the new textbook, Climate Change Science: A Modern Synthesis, deductive and inductive reasoning are discussed, pp 38-40.
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Bert from Eltham at 15:05 PM on 1 April 2013The Scientific Method
I work on a different level.
I just do not know.
I find out what is known.
I then pull apart all that I have found out.
If I have new information or insights I then publish to see what others think.
The others will soon let me know how far wrong I am.
When morons doubt the findings of this method because of their ignorance I wonder why I bother.
I should just make definitive statements about a subject I have no idea about and defend this position with even more definitive statements without foundation.
Bert
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