Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.

Settings

Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup

Settings


All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Donate

Twitter Facebook YouTube Pinterest

RSS Posts RSS Comments Email Subscribe


Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...



Username
Password
Keep me logged in
New? Register here
Forgot your password?

Latest Posts

Archives

Climate Hustle

Database of peer-reviewed papers: classification problematics

Posted on 31 May 2011 by Ari Jokimäki

While adding papers to the peer-reviewed paper database here in Skeptical Science, many problematic issues have emerged. In the database, papers are entered under certain skeptic arguments. For any paper, one can enter several arguments that are relevant to the paper in question. Each paper gets a classification pro-agw/neutral/skeptic depending on how the paper sees the argument in question. It is not very straight-forward task to assign a classification for each paper.

First of all, many arguments of so called climate “skeptics” are based on logical fallacies, especially on the logical fallacy known as “straw man”. When a straw man argument is made against the theory of anthropogenic global warming (AGW), the theory is misrepresented (straw man is being built) and then this misrepresentation (the straw man) is attacked. A common example of this is the argument “climate’s changed before”. AGW is misconstrued as claiming that climate has not changed in the past, and then this straw man is attacked with examples of past natural climate change, with the erroneous conclusion then being that humans cannot be causing this climate change.

How should we classify papers for this argument then? As the argument is a straw-man, there really can’t be many papers that can be classified as “skeptic” papers in the context of this argument. After all, logical fallacies are avoided in peer reviewed literature. However, the peer-review process is not perfect, so it is not impossible that some paper might have gotten through saying “oh look, there was warming in medieval times, so mankind can’t be causing warming”. If there are such papers, they should be classified as “skeptic” for this argument.

But what papers are “neutral,” and what papers are “pro-agw,” for the “climate’s changed before” argument? This is not very easy question to answer. My opinion is that the papers discussing past climate changes and suggesting that carbon dioxide can have a strong role in climate (and maybe even suggesting explicitly that their results support AGW theory) are “pro-agw” papers. Papers discussing past climate without taking a stand on the role of carbon dioxide or mankind on climate should be classified as “neutral”. Of course, there might be other opinions. In the future, we should synchronize our thoughts on this and document them in order to make this database more comprehensive.

There are some difficult arguments from a classification point of view, such as the "it's the Sun" argument. AGW theory doesn't suggest that there's no role for the Sun in Earth's climate, so how do we classify papers for this argument? A paper suggesting that the Sun has no role in Earth's climate whatsoever certainly seems to go against this argument, and while this would also go against mainstream climate science, it would be classified as pro-agw. Fortunately there are not many papers suggesting no role for the Sun (I'm not aware of any such papers).

On the other end of the paper spectrum, a paper might suggest that recent climate change is due to the Sun only. Such papers are "skeptic" papers. The middle ground between these two is the most difficult. There are papers saying that the Sun has had a warming effect during last few decades. The size of this effect varies by paper, so how much warming should a paper suggest as the contribution of the Sun to the recent warming so that we could classify it "skeptic" paper? Perhaps over 50%? What about a paper that suggests that sun has had a strong contribution to recent warming but CO2 is just taking over and will dominate in the future, is that pro-agw or skeptic paper?

One class of "it's the Sun" papers are the papers dealing with past climate changes and suggesting large role for the Sun. This is compatible with AGW theory which says that only in recent decades has anthropogenic CO2 become dominant climate forcing. Such papers should go to the neutral bin unless they also suggest that CO2 doesn't affect climate (or affects only weakly) in which case they should go to the skeptic bin. If a paper suggests a large role for the Sun in past climate changes but also emphasizes that CO2 can have a large role too, then the paper should go to pro-agw bin.

Papers addressing only part of the whole

There are a lot of papers that discuss certain parts of an issue but not the whole issue. There are papers that discuss certain weather events but not their climatic significance; some papers report regional studies, while the "skeptic" argument on that issue relates to the global situation; studies on single species are rarely conclusive from the perspective of the whole ecosystem. These are just a few examples of papers that address only part of the whole that is relevant to certain "skeptic" arguments. As a general rule, such papers should be put to the neutral bin. However, an exception to this rule is a paper that addresses only one part of the whole but claims explicitly to be relevant for the whole also. For example, if a paper reports warming in Finland and claims that it means global warming is happening, then we should put that paper to the pro-agw bin.

The issue of local v. global studies arises when a certain study concludes either a predicted response from AGW is (is not) happening, or explicitly concludes that AGW is (is not) directly observable or having an effect; but such study is of a specific location, and not global trends. It is not necessarily safe to assume that any effect observed in one area can be extrapolated to the entire globe, and as AGW theory most often deals with global trends, or trends dealing with whole biomes, we have generally agreed that local studies be placed as “neutral,” regardless of main conclusion.

I also think this same logic should be applied to research dealing with the effects of AGW on certain species: studies that focus on one plant species and how it will respond to AGW, for instance, are classified as “neutral” as well, as generalizations among plant species (especially) are illogical to make.

Of course, one question that arises is, “Where can the line in number of local publications be drawn so that a trend can be extrapolated?” While it is a good question, it is my opinion that that is not the point of the classification system. Papers can be referenced collectively to identify a widespread effect that extends beyond the local observations of each paper, but the limited extent of the observations of each individual paper subsequently limits the conclusions of each individual. As this database is to categorize individual papers by the explicit conclusions of the authors, and not groups of papers by the implicit agreement among them, it is my opinion that “lines” as above not be considered, and local/species-specific papers still be categorized as “neutral.”

We would also like to remind those using this database, though, that papers are also associated with related skeptic arguments to AGW, so papers can still be de-facto grouped together for careful analysis. 

Here we should also point out that sometimes "skeptic" arguments deal with only part of the whole. If such arguments are not straw men, then we should classify papers according to those arguments. A prime example of this is the situation with polar bears. There is the argument "polar bears are increasing;" for this argument, papers suggesting that polar bear populations are declining are "pro-agw" and papers suggesting that populations are increasing are "skeptic". However, also for this argument studies on a single population only should be considered "neutral" as they don't deal with the global situation of polar bear populations.

Other issues

In many cases a paper falls under many "skeptic" arguments. In and of itself, it's not a problem as the database allows several arguments to be assigned per paper. However, a paper can be "skeptic" for some argument while being "pro-agw" for some other argument. The database currently allows only one classification per paper so this is a problem. How do we select which argument we choose as the "primary" argument for which we determine the classification? The most obvious method is to select the argument which the paper addresses most, but sometimes that doesn't help. This problem requires future development of the database - perhaps classification for each argument is necessary.

Of course, we might ask what is the point of classifying papers by skeptic arguments anyway. Perhaps it would be better to ignore what the papers say about some "skeptic" arguments and classify the papers based on their support of AGW theory generally. These are issues that need to be thought of. Discussion on these matters is invited, but it is clear that further development is needed, and we especially need to set common ground rules for the classification of papers in the future.

Thanks to Alex C. who contributed substantially to this article.

0 0

Bookmark and Share Printable Version  |  Link to this page

Comments

Comments 1 to 40:

  1. "I also think this same logic should be applied to research dealing with the effects of AGW on certain species: studies that focus on one plant species and how it will respond to AGW, for instance, are classified as “neutral” as well, as generalizations among plant species (especially) are illogical to make."

    Isn't your definition of "neutral" going to artificially inflate the neutral bucket? A paper which is local in scope but which accepts AGW as causative or even axiomatic is not neutral in viewpoint, yet that is how it will be counted.

    I think you're right that you probably need to extend the database to cater for classification per argument rather than only per paper, but perhaps you also need more classification dimensions.
    0 0
  2. Caroza: "Isn't your definition of "neutral" going to artificially inflate the neutral bucket? A paper which is local in scope but which accepts AGW as causative or even axiomatic is not neutral in viewpoint, yet that is how it will be counted."

    As long as we are classifying these papers per argument, we need to do it like that. If the argument is global, then paper on one location is irrelevant for the argument, because local results can be remarkably different from global results.
    0 0
  3. Local results can have a global context.
    eg. if it can occur in one location, then logically it may occur in another location due to AGW given the right circumstances.

    Are there examples that can be discussed??
    Would be interesting.

    Maybe the neutral circles in the visualisation should just drop to the floor in a pile, rather than cluster in a group :-)
    0 0
  4. Paul: "Local results can have a global context.
    eg. if it can occur in one location, then logically it may occur in another location due to AGW given the right circumstances."

    Yes, but remember that we are classifying only a single paper, we are not making statistics of several papers of different locations. For that single local paper, it is impossible to say anything about the global situation.
    0 0
  5. I tend to dismiss these types of surveys as they are largely subjective. For instance, where would you classifiy a paper which concluded that global temperatures were influenced by the following factors in the given percentages? CO2:30%, solar: 25%, UHI: 20%, ENSO: 15:, albedo: 10%. (These numbers were completely made up and have no real bearing except to provide a basis for my hypothetical question.)
    0 0
  6. I think the point is not so much the classification of the paper itself (as due to the way science is conducted most papers will be neutral), but the potential for the conclusions to be misused or taken out of context by deniers.

    Or by alarmists for that matter, but that seems a rarer occurance.
    0 0
  7. Eric the Red wrote: "For instance, where would you classifiy a paper which concluded that global temperatures were influenced by the following factors in the given percentages? CO2:30%, solar: 25%, UHI: 20%, ENSO: 15:, albedo: 10%."

    Most likely classification: 'Fiction'

    If we are really talking about "global temperatures", rather than temperature anomalies, then the solar value is ridiculously low. If you meant to ask about anomalies then the solar, UHI, and ENSO values are ridiculously high.

    Obviously, it isn't really possible to classify such a hypothetical paper because we have no knowledge of the evidence shown for these conclusions. Based on known evidence they are beyond absurd, but the 'unknown evidence' of the hypothetical could be anything.
    0 0
  8. Eric the Red @5, in addition to CBDunkerson's well made points, I would add that the percentages you give are undefined because you provide no time period to your hypothetical. In the real world case, changes to CO2 forcing have a very small influence relative to ENSO on a year to year basis, but on a multidecadal basis they swamp the ENSO effects. So unless you specify whether you are considering annual, decadal, centenial, or (make your choice) variability, there can be no rational answer to your question.
    0 0
  9. Some thoughts

    1) It would be good to be able to suggest deletion of articles or movement of articles between categories.

    eg; checking the 2010 skeptic articles, I found that one is from Americanthinker "Climatism: Redoubling Misguided Efforts". Which doesn't belong in a list of peer-reviewed papers.

    eg: A paper listed in the 2010 skeptic articles is "Marine Reserves Enhance the Recovery of Corals on Caribbean Reefs", which is also listed under the myth "Corals are resilient to bleaching".
    Having had a quick look at the abstract and introduction it seems this paper is not skeptical about AWG or the threat of coral reef bleaching, but has identified a mechanism which can help reefs recovering faster from bleaching events. IMHO this paper belongs in the neutral section.


    2) Naomi Oreskes' classification method is quite good in that it help to get a the guts of whether a paper accepts the basic consensus around climate changes, which is: are humans warming the planet? Perhaps papers could be classified by both methods?


    3) Many papers are not shown to be wrong by specific rebuttal but simply become irrelevant over time.
    ie: a skeptic paper written in the 80's suggesting the climate was not warming or papers claiming the climate was not warming based upon the faulty UAH data. It would be useful if these could be marked in some way.
    0 0
  10. It's a mess.

    One thing I would suggest is identifying those arguments that are most relevant to the global picture and only taking those into account. So, for example, any paper addressing the "polar bears" argument is not pro, against or neutral... it's simply irrelevant.
    Of course, there are some studies whose relevance may be disputed. Is a paleoclimatic study investigating the climate 10 million years ago relevant to current warming? Some could say that it is since it may tell us a lot about climate sensitivity, but how much is difficult to say.

    I think that, in the end, we need to proceed as a scientist and look at the issue from multiple perspectives. Use different classifications schemes, filters and inclusion criteria and see what they tell us. A more compelling case can be made if the same conclusion (most papers agree with AGW) arises from multiple lines of evidence.
    0 0
  11. Hey Ari, nice to see you posting here.

    -------------------------------------------------------------

    I'd like to see papers centred around a value, like climate sensitivity, sea level trends or temperature trends. Eg, label a y-axis -2 to 12* (for climate sensitivity), and a vertical bar for each paper per the range each gives.

    So when a skeptic cites Lindzen climate sensitivity estimates, I can point to the graph that shows not only what outliers his estimate are and where the studies cluster, but how much work has been done. Skeptics pounce on a paper as if it's the final revelation, instead of one of dozens.

    That's the visual that I think will make the most impact. Seems like a lot of work, though.

    * I don't know what the range for climate sensitivity should be. I just made it up, like Eric did (I got you, ETR).
    0 0
  12. Your very first word is "Database". I don't know if you mean that, or if you are using a spreadsheet. Even the latter may have several columns. A database can be relational and support complex retrieval queries.

    On another note, after the incrementing numerical key (having nothing to do with anything else) and after after Author, title, journal and date fields, peer reviewed (Y/N), topic (sensitivity, sea level, etc), I prefer this main denier classification:

    0. none
    1. It's not happening
    2. It's not us
    3. It will be good for us anyway - or we don't know enough to justify doing the obvious, or at least taking effecting action (namely, stop burning carbon) will be worse than roasting ourselves. Note that delayers are a major type of denier.

    4. 1 and 2
    5. 1 and 3
    6. 2 and 3
    7. 1, 2, and 3
    8. Insane (for instance, greenhouse warming violates thermodynamics)

    There may still be related fields for specific arguments.
    0 0
  13. barry,
    That sounds nice in principle. However, the numbers could be skewed either way by a preponderance of papers surrounding a particular calculation or data. This could be further enhanced from a group of authors each pulishing a different version of the same paper as lead author. Finally, the results could simply be an indicator of someone's publishing abilities.
    0 0
  14. barry at 01:24 AM on 1 June, 2011

    It's a good idea, and Barton Paul Levenson has a very interesting list in those lines, including sensitivity estimates from Arrhenius 1896 until 2006. It even includes the statistical distribution:

    0 0
  15. Thanks for the link, Alexandre. I'll check it out after this post.

    Eric, yes, I thought of that, too. Is there a way to amend the idea to account for publishing abilities/re-published papers, etc, that a skeptic would find acceptable?

    Even if the cluster was centred outside consensus values, at least the extreme outliers would still be isolated (I suppose). A temporal x-axis, like the graph in the top post, would also show how the science has developed. In the climate sensitivity example, the bars would shorten (I suppose) as ranges become more contained over time. A short-hand way of showing diminishing uncertainty - on most, but not all topics.
    0 0
  16. This is the following graph on BPL's page;



    showing how the estimates have converged over time. just the sort of thing I'm thinking of. Thanks again Alexandre.
    0 0
  17. Sorry, I'm not ignoring all of you, but I don't think I have much time today to participate to the interesting discussion here. I'll be back later, though.
    0 0
  18. Few responses:

    Eric the Red: "For instance, where would you classifiy a paper which concluded that global temperatures were influenced by the following factors in the given percentages? CO2:30%, solar: 25%, UHI: 20%, ENSO: 15:, albedo: 10%."

    As the CO2 is dominant factor, and without knowing anything else about this hypothetical paper, I would put it to "pro-agw" bin.

    The Skeptical Chymist: "1) It would be good to be able to suggest deletion of articles or movement of articles between categories."

    You are welcome to do it here. I have moved the American thinker paper to "online articles" instead of "peer-reviewed". Thanks for the note.

    The Skeptical Chymist: "A paper listed in the 2010 skeptic articles is "Marine Reserves Enhance the Recovery of Corals on Caribbean Reefs", which is also listed under the myth "Corals are resilient to bleaching".
    Having had a quick look at the abstract and introduction it seems this paper is not skeptical about AWG or the threat of coral reef bleaching, but has identified a mechanism which can help reefs recovering faster from bleaching events. IMHO this paper belongs in the neutral section."


    Agreed. I have moved it to "neutral" bin, but if someone disagrees with this, please say so (with justification - simple indication of disagreement doesn't help much).

    Barry: "Hey Ari, nice to see you posting here."

    Thanks. I have actually made a couple of posts here before. One was on deep ocean warming and other one was just recently on a new cosmic ray research. I don't remember if there were other articles too. There's also one in the works right now.

    Pete Dunkelberg: "Your very first word is "Database". I don't know if you mean that, or if you are using a spreadsheet."

    This is a SQL database we're using.
    0 0
  19. Thanks Ari,
    Other posters seemed unable to comprehend the hypothetical situation, they seemed to get caught up in the actually numbers that I pulled out of the air. I purposely chose a situation were CO2 was the largest factor, but did not predominate, which was my main purpose. In such a scenario, temperatures would continue to rise as CO2 increased, but the climate sensitivity would be low as only 30% of the observed increase was a result of CO2. I would tend to classify papers which portray a low climate sensitivity as pro-agw also, although on a different thread running, I have seen people who believe this called deniers. Interesting dichotomy.
    0 0
  20. Eric the Red wrote: "In such a scenario, temperatures would continue to rise as CO2 increased, but the climate sensitivity would be low as only 30% of the observed increase was a result of CO2."

    I've been trying for several minutes now and I still can't get the above to make any kind of sense.

    How much warming is caused by CO2 vs solar vs UHI and so forth is irrelevant to climate sensitivity.

    Climate sensitivity refers to the response of feedbacks to forcings. The only feedback you listed was 10% of warming being due to albedo changes.

    Ergo, the scenario you set up has extremely low climate sensitivity because the only feedback effect which exists is changing albedo and that is generating much less warming than the three forcings and one internal fluctuation you list. You could change your numbers to 90% CO2 / 10% albedo or 0% CO2 / 90% solar / 10% albedo and the climate sensitivity would be exactly the same... determined by a single 10% albedo factor.
    0 0
  21. CB,
    The only thing relevent to the climate sensitivity is the total effect attributable to CO2.
    If the total impact to temperatures attributed to CO2 is 0%, then the climate is insensitivity to CO2, and the climate sensitivity (to CO2) would be 0. If it was 90%, then the climate is very sensitive to CO2, and the climate sensitivity would be high. I chose solar to be the next highest because it was used in the example above. I could have chosen any other forcings and numbers, but the only pertinent value is that associated with CO2. You could determine a separate albedo sensitivity, if you like, but it would not impact the effect of CO2.
    My intent was to determine at which point a paper ceases to become pro-agw and turn neutral, which is the essential question for which this thread was started.
    0 0
  22. Eric, the way you are using the term 'climate sensitivity', as explained in comment #21 above, is radically different from the standard definition used in most discussions here and regarding climate science in general.

    Again, most of us take the term 'climate sensitivity' to be the degree of climate feedback to any forcing. That is, whether the planet is accumulating heat due to increased solar output, an enhanced greenhouse effect, or a martian death ray, we can expect this additional heat to be partly offset by negative feedbacks and enhanced by positive feedbacks. The net feedback effect is the 'climate sensitivity'.

    While there would be some variation in feedbacks based on the type of forcing (e.g. a martian death ray aimed at the Arctic circle would introduce ice-albedo feedbacks faster than otherwise equal warming from increased greenhouse gases would) these variations are comparatively small and generally ignored when discussing the sensitivity of the climate to forcings.

    Most estimates put short term climate sensitivity to CO2 doubling at a total of about 3 C... 1 C from the CO2 itself and 2 C from feedback effects. Any other forcing which would produce 1 C warming by itself would also be expected to result in about 3 C total warming as the same feedback effects would apply.

    Thus, applying the usual definitions to your original statement I wouldn't call it 'pro-AGW', 'anti-AGW', OR 'neutral' so much as just 'wrong'. I can sort of follow where you were going based on your definitions of the terms above, but you'd probably be better served following standard usage.
    0 0
  23. Calling it "wrong" was not the purpose of this exercise, nor very meaningful. Since the climate sensitivity is derived from the warming effect of CO2, stating it as the effect that an increase of CO2 has on global temperatures is not "radically different." I was curious as to what people might think if the response to CO2 was presented as lower, while natural effects were presented as larger, while keeping CO2 at the top fo the list.
    I fully understand that the climate sensitivity is the final effect after all feedbacks are included, both positive and negative. The net feedback is the additional change caused by the original effect. In your post, the net feedback would be 2.
    Physics says the direct effect from a doubling a CO2 is about 1. Adding the effect from the increase in water vapor attributable to the increase in temperature usually results in a climate sensitivity of 1.8. After that, the calculations diverge significantly, primarily due to the treatment of clouds. If the other forcings resulted in a 1C cooling, then the feedbacks would also multiple the total to 3C.
    Papers have been published showing higher values for the other forcings than I presented. All I did was put them all together into one imaginary scenario.
    0 0
  24. Eric the Red - Please note that the various measures (as opposed to models) of climate sensitivity do not care which feedback is which. All they do is measure temperature change in response to forcings, total climate sensitivity.

    And those measured results (see this link, under "Climate sensitivity from empirical observations") strongly support a total sensitivity of 3°C for a doubling of CO2, or ~0.8°C for a 1 W/m^2 forcing.

    While we may not agree on how large individual trees are, we have a very good idea of the size of the forest.
    0 0
  25. I disagree that measured results strongly suggest a total sensitivity of 3C. Some research has suggested higher, others lower.
    Getting back to my original question. If a paper was published with a lower forcing attributed to CO2, and higher attributed to the other factors. Let us put temperature numbers on it: 0.25C from CO2 increase, 0.2C due to an increase in solar radiation (or sunspots), 0.15C due to the UHI, 0.1C due to ENSO oscillation (this would become negative in the future turning from a peak to a trough), and 0.05C based on total land changes. Using this lower value attributed to CO2 would reduce the total sensitivity in your link. The only number useful for calculating climate sensitivity is that for CO2 (all feedbacks included).
    Forget everything else if it is confusing, and answer this quesiton. At what level of climate sensitivity would you say the paper moves from being pro-agw to neutral?
    0 0
  26. Eric the Red - And why not just look at what those forcings are, and how much they are changing the current climate? Plenty of data on that, for example from NOAA, ESRL, NASA/Hansen, etc.

    Sensitivities to forcings are in the range 1.65°C to 4.5°C, most likely 3°C. This is supported by both models and empirical evidence, with that range shrinking over time with more data. The lower limit is both unlikely and very hard, the upper limit unlikely but less well determined.

    I really hate to say it, Eric, but your attempt to subdivide forcing percentages appears to me to be driving at minimizing the apparent importance of CO2. Sensitivity is to total forcing changes, including CO2, so (if all else remains the same) a CO2 change will induce just that much temperature change. And the same for a TSI change, an aerosol change, etc.

    You're attempting to re-define the vocabulary - that's really not kosher.
    0 0
  27. KR,
    You are getting further OT. The point was about classification about papers. When does a paper cease to become pro-agw, and become neutral?
    0 0
  28. Eric, quite correct on the topic point.

    Quite frankly, I don't know where that dividing line should be drawn. I would prefer placing them into categories of "correct", "incorrect", and "unproven" - with many of the anti-AGW papers being incorrect.

    The only neutral papers are those that aren't concerned with the climate.
    0 0
  29. Personally my opinion is that if a paper puts the most likely climate sensitivity value below 2°C for 2xCO2, it's neutral. Below 1.5°C I'd call "skeptic". But that's a tough call because the possible range of values would still significantly overlap with the IPCC range. So this is just my opinion.
    0 0
  30. One thing to note here is that apparently the argument of the classification seems to have changed. At least I understood from Eric the Red's original question setting that the argument would be something like "CO2 effect is weak" or perhaps even "it's the sun", but now you seem to be arguing about the argument "climate sensitivity is low". For that argument Eric the Red's original setting didn't give enough information so for that argument the hypothetical paper should be in "neutral" bin. Information missing from the setting are at least the effect of aerosols and the amount of warming that goes to warm the ocean and doesn't show in the surface temperature record. These both are effects that can mask lot of CO2 caused warming. You need to have total sum of forcings before you can determine how strongly feedbacks are acting.
    0 0
  31. Agreed Ari,
    My hypothetic paper was just to get a feel for where people thought neutral papers started, so that when I hear a certain percentage of papers are pro-agw, the understanding is somewhat clearer. There are several other effects that must be included in a complete analysis.
    I only changed to the climate sensitivity argument because some posters had difficultly the with original presentation of the question.
    0 0
  32. I am interested in clarifying the definition of climate sensitivity. CBDunkerson is talking in terms of percentages which I take to mean the fraction of Global Warming attributable to a particular GHG. As I had understood things previously, the senstivity is defined in trems of a constant k related to the relative inrease in CO2 or H2o or whatever as individual gases. For CO2 I believe k = 5.35 and appearts in te equation for an effective temperature increase od Delts_T = k ln(C/Co) where Co is the initial concentration in the atmosphere at time T and Cis the final at time T+Delta_T. Could someone pleae explain this for me.
    0 0
    Response:

    [DB] I think you'll find what you are looking for here:

    http://www.skepticalscience.com/detailed-look-at-climate-sensitivity.html

    Many other threads touch upon climate sensitivity as well.  Using the Search function finds this list.

  33. John,
    The constant k in the equation is not well defined. Using a k of 5.35 would generate a climate sensitivity of 3.7C / doubling of CO2, and is on the high side of recent estimates. Also, as pointed out in the link, the climate sensitivity is not precisely known, and usually portrayed as a range of values (i.e. 2.0 - 4.5, or 1.5 - 5.0), such that the constant k would be in the range 2 - 8. There are other issues that occur at high atmospheric concentrations of CO2, but this equation suffices for our current range.
    0 0
  34. John Nicol @32, Eric the Red @33, the equation 5.35*ln(C/C0) determined the change in forcing in Watts per square meter for a particular change in CO2 levels. For doubling CO2 that results in a change of forcing of 3.7 Watts per meter squared. To a first approximation, you can apply this as a change of forcing to the TOA incoming solar radiation to determine the change in temperature for a doubling of CO2 without feedbacks. By subtracting the change in Radiative Forcing from the OLR you can determine the change in the energy balance for no feedback. Using the Stefan-Boltzmann law you can then determine the increase in temperature required at the effective altitude of radiation to restore radiative balance. Because the temperature at the effective altitude of radiation is tied to that at the surface by a constant adiabatic lapse rate, the change in surface temperature is the same as the change at the effective altitude of radiation.

    Contrary to Eric the Red, this figure is very well understood, with uncertainties of only +/- 10%.

    The formula you are looking for is:

    "dT = λ*dF

    Where 'dT' is the change in the Earth's average surface temperature, 'λ' is the climate sensitivity, usually with units in Kelvin or degrees Celsius per Watts per square meter (°C/[W m-2]), and 'dF' is the radiative forcing"

    (From here)

    The standard value for λ is 0.8, with an uncertainty range of from 0.54 to 1.2

    That should be enough information to make any relevant on topic point, if any. If you wish to dispute these formulas or figures, we should go to the relevant thread as suggested by DB @32.
    0 0
  35. Tom,
    I agree that the radiative forcing directly due to CO2 is well known. It is the feedback loops that are less well known.
    Forgive me for short-cutting the equation, I was just trying to combined the two equations for John for simplicity purposes. I believe the uncertainty range you are quoting is one standard deviation, whil I posted a range of two.
    0 0
  36. Eric the Red @35, reply here.
    0 0
  37. Ari
    Again in the 2010 skeptic articles:
    "Accessing environmental information relating to climate change: a case study under UK freedom of information legislation" - is a SPPI report and does not appear to be a peer review paper and should be removed.
    0 0
  38. The Skeptical Chymist #37: Actually, that paper seems to be peer-reviewed. It was published in this journal (paper is listed in volume 22, issue1). The "report" seems to be a reprint of the journal.
    0 0
  39. Ari

    The 2010 paper "Expert credibility in climate change" is duplicated in the database.

    Also, once a paper has been added to the database, is it possible for anyone with the firefox add-on to add that paper to extra myths/arguments? The add-on looks like it should work for this but I find you can't send the report
    0 0
  40. A discussion over at Real Climate.org - see comment #24 - identifies a website with information about debunked anti-AGW publications (agwobserver.wordpress.com). A subsequent post by deconvoluter included “I think it is a mistake to include a minority of papers classified with a little (M) meaning a misunderstood main stream paper. They should be put into a separate list to avoid confusion. Otherwise it won’t be long before you see the authors of such (M) papers claimed by contrarians as supporting their position.”

    This information may be useful here. I have only superficially checked the referenced website, but it looks credible - like I'm the expert :)
    0 0

You need to be logged in to post a comment. Login via the left margin or if you're new, register here.



The Consensus Project Website

THE ESCALATOR

(free to republish)


© Copyright 2019 John Cook
Home | Links | Translations | About Us | Privacy | Contact Us