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Calculations of CO2 sensitivity from observational data

This article needs a big rewrite I think. This specific section gives an overview of different studies into ECS between 1998-2014. I think that is way too much detail and makes the article not sufficiently accessible. I think there should be three subsections under this heading with paleodata, industrial era data, satellite era data. There should not only be sample calculations, but first an explanation of the physical principles in English. Any objections to me rewriting in that way? (Got a few things to do first) Femke Nijsse (talk) 09:16, 13 March 2019 (UTC)

Amen! I have thought so for a long time but haven't known enough about the subject to even begin to wade through the poorly assembled technobabble NewsAndEventsGuy (talk) 10:45, 13 March 2019 (UTC)
Cool. My research group is involved in constraining ECS, so I should have the knowledge. But that also possibly opens the door to some conflict of interest. I'm myself involved the following work: https://www.nature.com/articles/nature25450, so I would appreciate it if you could look at contributions involving this technique with an extra dose of skepticism. Femke Nijsse (talk) 12:03, 13 March 2019 (UTC)
I'll try, but.... hello William? Are you listening? Femkemilene... if you have not already done so, you may wish to review WP:COI, which is about conflict of interest editing. NewsAndEventsGuy (talk) 12:23, 13 March 2019 (UTC)
Thanks. The relevant advice from that page: When in doubt, defer to the community's opinion: propose the edit on the article's talk page and allow others to review it. I'll do that. Femke Nijsse (talk) 12:40, 13 March 2019 (UTC)
Great! NewsAndEventsGuy (talk) 14:50, 13 March 2019 (UTC)

Easy and undisputed?

The phrase "is easy to calculate and is undisputed" for Jules Charney's proposed factor of 3.7 W•m−2•K−1 seems out of place in an encyclopedia. If it really is easy to calculate then why is the calculation not given, as is customary with easy calculations? If it is actually difficult to calculate then it might be undisputed because it is difficult to dispute that which is difficult to calculate in the first place.

Let me suggest the following way to compute it. I'm pointing this out because (a) if there's an even easier way already in the literature then that way ought to be in the article, and conversely (b) if there isn't then I dispute Wikipedia's claim "is easy to calculate" as being unsupported by any RS.

The relationship between small changes in temperature and small changes in radiative flux is given by the derivative dF/dT of the Stefan-Boltzmann law, namely dF/dT = 4σT3. The value of this relationship at any given temperature provides a conversion factor between the two kinds of small changes, temperature and radiative flux. This holds for all radiating objects, not just planets.

If the effective temperature of Earth is taken to be 254 K, this conversion factor is 4σ*5.67*254^3 = 3.72 W•m−2•K−1. A degree either way bumps this number up or down by 0.04 W•m−2•K−1.

The question then arises as to how this bears on surface temperature. That's easy: assuming constant lapse rate, the same change in temperature should occur at all altitudes in the troposphere from the surface to a little below the tropopause, the region where most of Earth's radiation to space comes from.

(This calculation ignores emissivity ε because if it is taken to be ε = (254/288)3 = 0.686 and the derivative is evaluated at the surface temperature of 288 K, as appropriate when including emissivity in the Stefan-Boltzmann relation, the outcome is unchanged. But in general emissivity of gases is a notoriously difficult concept to theorize about, and it is better to ignore it and work with Earth's effective temperature. In equilibrium, when the radiation and the temperature are measured at the same point the emissivity should be 1.)

There may well be another way of computing this quantity that is either easier to calculate or more faithful to the physics than the connection made here between changes in effective temperature and changes at the surface (or better yet, both!). If so it would be nice to know about it. If not I propose removing the phrase "is easy to calculate and is not disputed" and instead stick to merely citing Charney as its source. Vaughan Pratt (talk) 21:07, 17 March 2019 (UTC)

Thanks for your comment!
I agree that the current wording is a bit shaky. The statement that it's undisputed especially needs a RS. I think the RS on the next sentence covers it as well, but I'll check that and duplicate that reference so that it's clear it provides backing for both sentences.
Your calculation is basically the one found in the literature as far as I'm aware. I want to simplify, and reduce the amount of maths in the article, but I think this is an easy example that should be included. I'll come back once I've read a few more RS that cover CS in general. The maths should be less annoying as well if we put in separate equations instead of in the middle of sentences.
I'm pretty sure there is not an easier way to compute this. Methods that are a bit more true to the physics that take into account the latitudinal effects (varying albedo??) come up with a slightly higher number (1.2 K). Femke Nijsse (talk) 09:48, 18 March 2019 (UTC)
I've included the calculation in a note. I intend to keep this article accessible to 14-18 year olds, as I certainly think they are a potential audience here. The derivation required a derivative, so I put it in a place where it doesn't scare people too much. If you think it should have a more prominent location, I'm open to discussion how to best implement it. Femke Nijsse (talk) 21:02, 26 March 2019 (UTC)
Thanks, Femke. I would have said something about the value of the derivative at 255 K being 3.74, and that its meaning is a conversion factor between fluctuations in radiative flux and fluctuations in temperature. Also the assumption of constant lapse rate is what justifies its relevance to surface temperature.
Where can I read about the 1.2 K value you mentioned? It would be plausible if the centennial feedback gain were 0.83, which would account for an observed centennial climate sensitivity of a tad over 1.9 degrees per doubling. Vaughan Pratt (talk) 02:56, 30 March 2019 (UTC)
In the derivation I explicitly stated that there are no feedbacks. This also contains the lapse rate being held constant. I don't see why that feedback should be emphasized over other feedbacks.
The source I cited (Roe, 2009) contains this number of 1.2 K, which is consistent with estimates of the Planck feedback in GCMs (source IPCC AR5, chapter 9). Roe states: "For an equilibrium temperature of 255 K, λ0 = 0.26 K (W m−2)−1. In practice, the finite absorptivity of the atmosphere in the longwave band means that, in global climate models, the reference climate sensitivity parameter, determined after removing all dynamic feedbacks, is 0.31 to 0.32 K (W m−2)−1". I have delved a bit in the sources that Roe cited, but I don't understand those fully.
In this back-of-the envelope calculation, they get a value around 1.2 K, but they make a questionable assumption around the lapse rate. http://www.atmos.albany.edu/facstaff/brose/classes/ATM623_Spring2015/Notes/Lectures/Lecture03%20--%20Climate%20sensitivity%20and%20feedback.html. Their lapse seems to provide a positive feedback, whereas in GCMs this feedback is negative.
Another paper does support my assertion that varying spatial patterns (both vertically and horizontally) of temperature can change the value of the no-feedback CS: http://www.meteo.mcgill.ca/~tmerlis/publications/henry_linear_rad.pdf. It does not explain why Planck feedback is around 3.2 instead of 3.7. As I think this is technically way too difficult to include in the article, I will not delve deeper in this matter. If you find a good explanation, I'm all ears. Femke Nijsse (talk) 13:09, 30 March 2019 (UTC)

Good article nomination: what needs to be done still?

I'm now getting somewhat satisfied with the article. Most individual studies are replaced by an overarching story and recent concepts are included in the article as well. It's a bit slimmer than it was before.

What still needs to be done for good article nomination:

  1. Replace the last individual studies with overarching story. DONE
  2. Add figure detailing differences TCR, ECS, ESS. DONE
  3. Asking the guild of copy-editors to look over it, as the article is quite technical and we can use all the help in the world to make it easier to understand. DONE
  4. (Maybe asking some colleagues to go over it; see whether there are subtleties I missed)
I've asked Twitter and that exploded a bit. Got quite a few comments to improve the article further, and implemented some of them. Femke Nijsse (talk) 21:10, 28 April 2019 (UTC)
For transparency, the comments I got on Twitter by various climate scientists:
  1. Maybe add a time scale to the figure explaining the differences between TCR, ECS, ESS.
  2. Make sure that the wording is clear in statements such as A, B or C. If there is possibly a D, write this down.
  3. Note that CS is a globally averaged variable
  4. Make clear what the first figure is; why authoritative?
  5. Explanation effective climate sensitivity unclear?
  6. The new CMIP6 models have way higher ECS. Are they mentioned? (I have decided not to include them, as they have not really been analysed independently yet. Maybe in half a year). Femke Nijsse (talk) 10:50, 29 April 2019 (UTC)


What am I missing? Femke Nijsse (talk) 11:15, 31 March 2019 (UTC)

Insert following sentence

Can the following sentence (or some modification of it) be added to the article (penultimate sentence)? Of course, the bare links can be made full citations by the tool that does that. I'm linking the original study, and one of the responses to it and our response to the response, so that the interested reader can just for themselves to what extend to believe this strategy. I want to include it to link to the Schwarz study earlier in the article.

As I'm a coauthor to the last of these papers, I leave it up to you to decide whether it should be included.

The time scale at which a climate models respond to perturbations has been linked to climate sensitivity too.[1][2][3] — Preceding unsigned comment added by Femkemilene (talk • contribs)

References

  1. ^ https://www.nature.com/articles/nature25450
  2. ^ https://www.nature.com/articles/s41586-018-0638-5
  3. ^ https://www.nature.com/articles/s41586-018-0641-x
Not sure I properly understood this but I have instead attempted to add a phrase from the first abstract to an existing sentence. If wrong please correct it. Maybe also another layperson could comment on whether it is understandable and also whether to add the 2nd and 3rd cites given that they require payment. Chidgk1 (talk) 11:05, 7 May 2019 (UTC)
Thanks, looks good :). The reason I included the other two sources is to lead interested readers to the discussion of the paper, which contributes quite a bit to the understanding of the paper. Femke Nijsse (talk) 11:27, 7 May 2019 (UTC)
Of course - not just to get your name in Wikipedia :) - I have added them

Equilibrium being a misnomer

Hello Femkemilene, [still not sure how to enter response] I just did a google search on "climate system equilibrium "steady state" " finding some 350 000 hits (I did not read them all!) but this search seems to demonstrate that use of the terminology "steady state" is not uncommon. A rather nice paper (in that it supports my view on terminology) is that of Paltridge, [The steady‐state format of global climate GW Paltridge - Quarterly Journal of the Royal Meteorological …, 1978 - Wiley Online Library], about the 5th hit down from the top, dealing with non-equilibrium thermodynamics and entropy production of a steady state system. So this paper draws a clear distinction between an equilibrium system and a steady state system. I tend to admire precision, in language and for that matter, more generally. Otherwise words can mean whatever we want them to mean. Alice in Wonderland. Soccer59 (talk) 03:18, 1 July 2019 (UTC)



User:Soccer59. I just deleted the note that equilibrium climate sensitivity is a misnomer. I performed an extensive google search, specifically fishing for a RSs that would support this, and even with this questionable strategy, I did not find a reliable source for this statement.

From a physics background, I can understand why you would like to add this qualification. The word equilibrium in physical systems is sometimes used instead of thermodynamic equilibrium, which has a very specific meaning. In the sense of that definition, equilibrium is a misnomer. But articles and reports about climate sensitivity never claim the system is in thermodynamic equilibrium, but instead in global radiative equilibrium, which simply means the radiation leaving the earth is the same as what comes in. This is a theoretical concept as variations in both incoming and outgoing radiation can be considerable. With so many definitions of equilibrium around, you cannot claim one is wrong because a different one exists. Femke Nijsse (talk) 16:40, 23 April 2019 (UTC)

Hello Femkemilene, I am not sure I am following the correct protocol by doing an "edit" to your remarks, but this is the only mechanism I know of to respond. I just checked the page https://en.wikipedia.org/wiki/Radiative_equilibrium, which deals with the definition. It gives a specific example
Definition for an entire passive celestial system such as a planet that does not supply its own energy
Global radiative equilibrium
Liou (2002, page 459)[16] and other authors use the term global radiative equilibrium to refer to putative or theoretically conceived radiative exchange equilibrium globally between the earth and extraterrestrial space; such authors intend to mean that, in a putative or theoretically conceived steady state, incoming solar radiation absorbed by the earth and its atmosphere would be equal to outgoing longwave radiation from the earth and its atmosphere.
This example makes it clear that the situation described is a steady state, but that the term equilibrium is used by some authors. I have no quarrel with that usage provided it is made clear that the situation described is not an equilibrium or even a radiative equilibrium as discussed earlier in the above article. So I suggest that the qualification be introduced at first use. Soccer59 (talk) 00:25, 1 May 2019 (UTC)
Hello User:Soccer59. You're indeed following the right protocol by doing an edit to my remarks :). Welcome to the discussion pages of Wikipedia! I've added a colon to all of your sentences, which indents the sentences, so that it remains clear who says what.
You state that you think that the term equilibrium is used by some authors. My perception of the literature (I'm doing research on climate sensitivity this myself) is that it's used by all authors writing about climate sensitivity.
The most important reason I think it should not be added is that there is, as far as I'm aware, no literature specifically describing equilibrium climate sensitivity as a misnomer. If you can find a reliable source on climate sensitivity that mentioned equilibrium being a misnomer, I have no objection to adding it. I cannot find such a source though, and I have spend quite some time looking for it.
Notice that the page Radiative equilibrium#Definition for an entire passive celestial system such as a planet that does not supply its own energy does something against wikipedia's guidelines: it is giving an opinion on its own sources. It uses for instance the terminology such authors intend to mean that and some good texts. These statements are actually not supported by reliable sources; at least not by the sources cited. This is in my opinion an example of Wikipedia#No original research#Synthesis of published material. Preceding unsigned comment added by Femke Nijsse
I'm a little unclear what the discussion is here. The word "equilibrium climate sensitivity" is used to distinguish it from "transient climate sensitivity": https://www.gfdl.noaa.gov/transient-and-equilibrium-climate-sensitivity/ (I'll add that as a cite when the words are defined.) Some papers discussing the difference are here: https://www.gfdl.noaa.gov/transient-sensitivity/
These are the short-term and the long-term response to a change in forcing. Equilibrium is easier to calculate; transient is easier to measure (or at least faster, since in principle equilibrium is asymptotic to infinity). Geoffrey.landis (talk) 14:14, 19 June 2019 (UTC)
Femke Nijsse's comment is right, the section of the article on Radiative Equilibrium dealing with "celestial systems" was poorly written and incorporated multiple editorial opinions that look like OR to me. I did a little rewriting to try to damp down the opinions (could use a more thorough revision, but I'm short on time). Geoffrey.landis (talk) 15:09, 19 June 2019 (UTC)

Decadal variability

@Chidgk1: added a section about the variability and climate sensitivity. As I'm the lead author of this study, I will not directly edit this section. (honoured to be added to Wikipedia :)). I do have some suggestions for change however. Do with it as you please.

  • I'm not sure whether it's sufficiently important to warrant inclusion here.. But that's for others to judge.
  • I've removed a lot of information about where studies are done and where they were published. This Wikipedia article is already relatively long, and these details are not really important.
  • The study was done as a collaboration between Exeter and Centre for Hydrology & Ecology.
  • An opinion piece is not really a RS. If we want to keep it, it would maybe be better to refer to the paper directly.
  • The study showed a symmetry between faster and slower than average. The word sometimes should be removed for accuracy.
  • Can we put it in a different section? It's now a overly short section. Femke Nijsse (talk) 10:00, 30 July 2019 (UTC)

Timeline of published climate sensitivity estimates

https://www.carbonbrief.org/guest-post-why-results-from-the-next-generation-of-climate-models-matter has an interesting graphic of various estimates. Not sure if that could be usefully used (if permission sought).

Some other notes on the article: Other strategies includes details of attempting to use solar cycle. I would have expected attempts to use response to volcanic eruptions to be mentioned, perhaps more prominently than solar cycle.

Thanks for your comments :). I could seek permission to use that. I spoke to one of the editors recently, and he said that using their graphs should be possible: they publish them under some sort of copyleft license, if I recall correctly.
About the volcanoes: I'm aware of at least one paper that explains why we theoretically expect not to be able to constrain ECS, or even TCR, well with volcanic eruptions. Will add this article. (OR warning: My own experience studying volcanic responses in models confirms their finding of this being really difficult.) Femke Nijsse (talk) 10:59, 5 August 2019 (UTC)
Thanks :) Probably should have explained earlier that I am aware of this paper, 'Using multiple observationally-based constraints to estimate climate sensitivity', [1] which includes "The short-term large-scale cooling following volcanic eruptions has also recently been used to estimate climate sensitivity [Wigley et al., 2005; Frame et al., 2005; Yokohata et al.,2005]" which was why I expected more mention for volcanic than solar cycle. These could easily be outdated by more recent work you quote. You can clearly make more knowledgeable assessment of whether any inclusion is appropriate. crandles (talk) 18:17, 5 August 2019 (UTC)
I know there is a new paper in the making (I think submitted a few months ago) that has also looks at a set of different evidence (observational, paleo & model). Curious how much they will include volcanoes. I'll add a couple of sentences about it this week. Femke Nijsse (talk) 15:37, 24 September 2019 (UTC)

TCRE

This article misrepresent the transient climate response to cumulative carbon emissions (TCRE) as TCR and fails to provide a full and robust definition of TCRE. To address this problem I am drafting a new article dedicated to TCRE (which is different subject than ECS, as evidenced by a significant amount of research and publication on the subject over the past decade) which will be linked to the climate sensitivity article. This new article will partially follow the TCRE review paper by Matthews et al. 2018 [1] — Preceding unsigned comment added by AlexanderMacIsaac (talk • contribs) 04:45, 20 February 2018 (UTC)

I've now included a correct definition of TCRE. I think it is a matter of taste whether the articles should be merged. I think not, because they are often discussed in different contexts. Femke Nijsse (talk) 18:40, 30 March 2019 (UTC)
I'm assuming this is Transient climate response to cumulative carbon emissions. Ratio per unit? HLHJ (talk) 02:03, 25 February 2020 (UTC)

References

  1. ^ Matthews, H.D., et al. (2018). Focus on cumulative emissions, global carbon budgets and the implications for climate mitigation targets. Environmental Research Letters 13.1, http://iopscience.iop.org/article/10.1088/1748-9326/aa98c9

Bad prose?

I am really confused how this article passed the GA process without a significant overhaul of the prose: there are dozens of moments where the passive voice, and the relatively poor syntax of the sentences make the article very hard to understand. Some examples, just from the lead:

  • "Climate sensitivity is a measurement of how much warming is expected," -- who expects warming? Why are they expecting? Why are they asking that question?
    Improved?
  • "it is the globally averaged surface temperature change in response to the changes in radiative forcing, the difference between incoming and outgoing energy on Earth" -- what does it refer to? averaged is not really a easy to understand verb when not describing a number, and I am not sure how you can average "in response" to something... what is radiative forcing? what do you mean by "incoming and outgoing energy"?
    That sentence contains the actual definition of climate sensitivity, and I understand not everybody will be able to understand. I've added 'in technical terms' to the sentence, to make sure a more general public doesn't expect to understand the sentence in full. I see you've deleted the globally, so that there is not uncertainty whether the average of temperatures is taking over time, or over space. Before I change back, why did you want to delete that?
  • "In the context of global warming, different measures of climate sensitivity are used." -- by whom? Why does global warming have a context?
 Done
  • "The magnitude is likely between 1.5 and 4.5 °C." What do you mean by magnitude? who describes if its likely? Why isn't there a reference?
    Added a reference. The likely value is from the authority on climate change matters, the IPCC. I don't like introducing specific organisations in titles when their opinion is shared by the vast majority of scientists. Femke Nijsse (talk) 21:30, 21 February 2020 (UTC)
  • "The long timescales involved with ECS makes it arguably a less relevant measure for policy decisions around climate change." huh? This is a really confusing sentence.
    I don't understand why this is illogical. Policy is typically not done thinkign of the distant future. Femke Nijsse (talk) 21:30, 21 February 2020 (UTC)
  • "This is useful as a gauge for what temperature change can be expected over the current century. " -- guage is a complex metaphor not compatible with international english. useful for whom? Current century? Next 100 years? 80 years from now by 2300?

There is a lot of great information in this article, and that the overall structure is quite good -- but it certainly doesn't meet the "well written" criteria: its actually quite hard to understand from a lay audience perspective. @Stingray Trainer and Femkemilene:: I am really struggling with the prose, and the number of weird and abstract, hard to process sentences in the article, this page needs a serious copy-edit to be approachable for anyone not in the field. Sadads (talk) 01:52, 18 February 2020 (UTC)

Thanks for chiming in! I'll try to address some of your points, but I might later need some explanation of why things are difficult to understand. My scientists' brain can be a bit adled :P.
When I don't understand an article I often look at the Simple English one (although I don't remember any of us kids calling Margaret Thatcher a neoliberal after she took away our school milk) so I have written simple:Climate sensitivity. If I have added any scientific mistakes it would be great if someone could fix them or point them out at simple:Talk:Climate sensitivity
I hope I have not been too presumptuous and have requested a copy edit from the experts but suggested whoever does it asks first if they don't understand something themselves.Chidgk1 (talk) 16:07, 19 February 2020 (UTC)
@ Chidgk1: I had a quick look at your simple English article and didn't spot any mistakes
@ Sadads: I hope I've been able to clarify all of your points. Any more feedback? Femke Nijsse (talk) 21:30, 21 February 2020 (UTC)
@Femkemilene: Sorry for being so slow to respond -- its been a crazy couple weeks. As you saw, I started editing yesterday in the first couple sections: I think its feeling a lot better where its at now. The rest of the article has a lot of very hard to understand sentences. I will start dropping them here as I run into them. Hopefully you can correct the things I fix to make sure they are accurate -- I am trying my best to interpret what is implied by the articles. Sadads (talk) 15:49, 22 February 2020 (UTC)
Never worry about being slow :). Two more 'clarification needed' tags have been placed in the background section that I cannot place. Could you expand? Femke Nijsse (talk) 16:28, 22 February 2020 (UTC)
@HLHJ: is doing more of the good copyediting -- clarifying better than I have been. @Femkemilene: see the notes below for the specific tags. Sadads (talk) 13:54, 24 February 2020 (UTC)
Thanks, Sadads! I've been a bit dragonish and have added a fair amount of unsourced explanation, some of which may be superfluous. I have mainly edited for clarity. There is still an ontological problem in that the references to the varying timescales are a bit fuzzy, and terms may be tacitly limited to a single point, the effects of atmospheric CO2 levels double the preindustrial levels, or may be broader term for effects as a function of atmospheric CO2 concentration. Please let me know if anything I've written is unclear. HLHJ (talk) 04:16, 26 February 2020 (UTC)
@HLHJ and Femkemilene: This is feeling much more right than it was --- I am sure that there are plenty of improvement still, but at least the first couple sections are thoroughly readable and approachable by a broader audience, and most of the rest of the article doesn't get lost in the hard to read language -- it takes the time to explain assumptions about what the audience knows.
However, that we were able to do so many revisions with so little expertise on the topic, suggests to me that it should have gotten more peer feedback from @Stingray Trainer: and others during the Good Article process. The criteria for "the prose is clear, concise, and understandable to an appropriately broad audience;" means that you should be able to read it with limited or no context or assumption of literacies -- non-native speakers would have had a hell of a time reading the earlier version, and as someone with a graduate degree, and fluent in English I couldn't understand it as it passed during review.
Anyway, great job all at revising this so far -- I hope we can get all the citations and related improvement of the content so that it continues to hold up the GA criteria. Sadads (talk) 15:44, 29 February 2020 (UTC)

Further concerns

  • "In time-dependent estimates of climate sensitivity, the concept of the effective radiative forcing, which includes rapid adjustments in the stratosphere and the troposphere to the instantaneous radiative forcing, is usually used." -- not sure what this sentence means -- its very cryptic.
    I don't think it's strictly necessary to talk about this concept in this article. The sentence was also slightly wrong; we use effective radiative forcing for loads of things, not only for 'time-dependent estimates of climate sensitivity'. Removed.
  • "The radiative forcing caused by current levels of atmospheric CO2 is now over half of the forcing that would[clarification needed] occur if CO2 concentrations doubled" -- I am really confused about the way in which we describe doubling is there a time period? What do we mean by over half? Wouldn't it be logical that half of the forcing would be at half of the doubled CO2? There are a lot of assumptions here and each time I reread it I don't think I understand what you mean by the the sentence cause me to reread. Sadads (talk) 13:45, 24 February 2020 (UTC)"
  • "Over the same period,[clarification needed]" -- you don't describe a period in ^ quote. Sadads (talk) 13:47, 24 February 2020 (UTC)
  • "transient[clarification needed]" -- what does transient mean in this context? Transient suggests that something is vagrant and doesn't have a home....Sadads (talk) 13:48, 24 February 2020 (UTC)
  • "transient" means "remaining for only a brief time". Before asking what a word like "transient" or "magnitude" means, please take a moment to look it up in a dictionary. I have linked to definitions of those two words for you; there is a search box at the top of each Wiktionary page to look up additional words. There are many unclear sentences in this article, and I will work on copy-editing it, but asking basic questions about definitions of (admittedly, not the most common, but still reasonable to use in an encyclopedia) English words muddies the discussion. – Jonesey95 (talk) 15:37, 24 February 2020 (UTC)
  • @Jonesey95: instead of inferring "you must be so stupid, you didn't look in the dictionary" in reading my question, its worth trying to figure out why its confusing in this context. As we discovered in going back in forth on it the original author was trying to use a specific definition and because of how the sentence was written I didn't realize that. I am trying to wear the hat of a non-scientist, non-expert in the copyedits, which means I am challenging the language because I think the bulk of the readers of the article (now nearly 5000 pageviews a month), are probably not English native speakers and/or don't have college level science degrees. With my English master's degree hat on, I would never use transient as an adjective before that noun -- the adjectival uses case would only be related to clearly temporary noun objects in a sentence like "The transient band of nomads gathered their gear to travel". Sadads (talk) 22:59, 24 February 2020 (UTC)
  • As part of assuming good faith, please do not assume what I am inferring. As far as I can see, the word "transient" is used only as an adjective before nouns and noun phrases like "response" and "climate response", phrases that are defined at least twice in the article and placed in close contrast with phrases describing longer-term climate response, providing further context for readers about the meaning of the word "transient". I will work on copy-editing the article for additional clarity. Also, when you add a {{clarify}} tag, please fill in the |reason= parameter so that other editors can address the clarification that you feel is needed. Thanks. – Jonesey95 (talk) 23:37, 24 February 2020 (UTC)

Should "band sensitivity" be added?

11 minutes into this video the lecturer seems to say that ANY doubling would give an increase of about 4 W/m2

I would intuitively have thought that the second doubling would give a much bigger increase.

This video says it is due to the band sensitivity effect - so maybe that should be explained in the state dependence section?

Or perhaps not if it is out of date due to improved cloud modelling?

Chidgk1 (talk) 06:51, 21 February 2020 (UTC)

The lecturer is right. As greenhouse gases get more saturated in the atmosphere, adding more gets less effective. As this is about forcings and not feedbacks, clouds don't influence the process.
If we want to explain more about it, it should probably be put in the radiative forcing subsection of background.. I would like to keep that section simple, so my preference is not to include it in the article, unless we find a real easy explanation/analogy. Femke Nijsse (talk) 07:59, 21 February 2020 (UTC)


Comparison of the absorption spectra of CO2 and H2O
IR window. Click through to Commons and mouseover for vertical rulings
Chidgk1, the relevant physics background for this is infrared window, which could do with some work. Fluorescent radiant cooling exploits this atmospheric window, and is interesting.
This article currently concentrates almost entirely on sensitivities at CO2 levels of 560ppm. The article would benefit from adding graphs showing wider ranges of CO2 concentrations, including concentrations below 280ppm (based on models and paleoclimatology).
This is an important and rather technical topic, and hard to write and review. The article has a lot of trivial problems which should be removed by a good copyedit before the GA (such "impact of X.. to Y", difficult syntax, pronouns not agreeing with ancedents, capitalization errors, etc.). The article also has some deeper problems with being accessible and easily comprehensible. I regularly write articles with both these flaws; it's hard to spot your own errors and assumptions. I've gone over part of it and will try to work on it some more. HLHJ (talk) 07:00, 24 February 2020 (UTC)
Thanks for helping out! I've spent some time searching for a graph for state sensitivity or data to reproduce one. The only one I encountered was https://skepticalscience.com/print.php?n=1458 from a Hansen paper, and I don't believe it's freely available. The problems with copyedit will hopefully be tackled by the GOCE soon. Femke Nijsse (talk) 07:51, 24 February 2020 (UTC)
Most of the figures on that page are available under CC-BY here, but that top one is not. It might be in the supplementary material at http://dx.doi.org/10.1098/rsta.2012.0294, but I'm getting a 404. Actually, I can't find the published version of the paper it's taken from. I'll have a go at this. Separately, I remember seeing an IPCC summary graph plotting temperature rise against CO2 emissions, though I can't find it at the moment. HLHJ (talk) 03:08, 26 February 2020 (UTC)
Femke Nijsse, I've got permission to use it and uploaded it at File:Hansen_&_Sato,_Climate_Sensitivity_Estimated_From_Earth's_Climate_History_Figure_7.pdf and File:Hansen_&_Sato,_Climate_Sensitivity_Estimated_From_Earth's_Climate_History_Figure_7.png; once the OTRS goes through, I will make an SVG version. HLHJ (talk) 03:40, 5 March 2020 (UTC)
I've made an SVG version and added it, with a bit of content context. HLHJ (talk) 04:37, 6 March 2020 (UTC)

What should the short description be?

I think this is tricky because there seems to be more than one definition of "climate sensitivity" so should it include both?Chidgk1 (talk) 11:00, 21 February 2020 (UTC)

I'm not sure. The two most common definitions (TCR and ECS) are about doubling of CO2. ESS is sometimes defined for doubling as well, but can be used generally as well I believe. The climate sensitivity parameter, however, is any increase of forcing. Maybe stick to the more general definition? Femke Nijsse (talk) 22:22, 6 March 2020 (UTC)

Requested copy edit

A copy edit of this article was requested at Wikipedia:WikiProject Guild of Copy Editors/Requests on February 19. I accepted the request and worked on the citation templates and convert templates, but I decided to wait on a full copy edit while other improvements were discussed and implemented. The article has been improved significantly, and since it has been pretty quiet around here for a few days, I am going to begin a full copy edit of the article. Please bear with me and discuss here if I change something that you don't like; if you change it back right away, we will no doubt have edit conflicts, which are no fun for anyone.

I will post here if I have any questions and when I am done. Thanks for your patience. – Jonesey95 (talk) 18:13, 9 March 2020 (UTC)

Great! Thanks. I see some of my Dunglish being polished away. We now have two section with definitions however (measures of climate sensitivity & definitions), and possibly the most important words 'equilibrium climate sensitivity' disappeared from the lede. I think having those two terms (ECS/TCR) in the lede was better before. Femke Nijsse (talk) 20:16, 9 March 2020 (UTC)
Noted. I will revisit the lead after I get through the rest of the article. With long articles, I find it easiest to edit the lead after I have seen the whole text. – Jonesey95 (talk) 20:21, 9 March 2020 (UTC)
I have attempted a shorter version of the definitions in the lead. As with all leads, it is best to save the details for the full article, but if I have left out anything crucial, please modify as you see fit. – Jonesey95 (talk) 23:39, 9 March 2020 (UTC)

Feedback and questions from copy editor

Questions for talk page watchers:

  1. Was "Applications" the right title for the section immediately under "Background"? I changed this section heading and put the two sections in a more logical order, since radiative forcing is explained in one section and then referred to in the other.
  2. In general, are the section heading titles reasonable? I sometimes had trouble justifying the titles after reading the sections, but I didn't want to change all of them.
  3. I have commented out a section under "Contributors to climate sensitivity". Do we still need it? If so, it is not well explained. Maybe it belongs in a footnote or in a different part of the article.
  4. I did not find the section "Effective climate sensitivity" to be informative at all. I read the definition of it in the Annex III Glossary, and I was left similarly unenlightened about the meaning or usefulness of this measure. Do we need to include it? If so, we should provide at least one example of why we are mentioning it at all.
  5. Re Sensitivity to nature of the forcing: This section says that aerosols are "more effective" than CO2 at warming, but what does that mean? More effective per ton emitted into the atmosphere? This section needs a more thorough explanation of what it is trying to communicate.
  6. I have removed the block of text immediately below the heading "Estimating climate sensitivity"; it appeared to be redundant. If there is some nuance that I missed in that section, the ideas in it should probably be incorporated into another relevant section instead of being restored wholesale.
  7. I have left behind some {{clarify}} templates. Do whatever you like with them. If I am just missing a clearly stated point in a particular case, feel free to remove the corresponding template.
  8. James Hansen's estimate for climate sensitivity is provided, but I was unable to locate a source or a year for his number in the article. A citation should be provided.

More to come. – Jonesey95 (talk) 20:21, 9 March 2020 (UTC)

I have completed my copy edit. I put in a couple more {{clarify}} templates and maybe one or two other questions. I will watch this page for a while in case any of you have questions about my editing choices. If I made any clear errors, jump right in and fix them. If you think I made an error but you want my reasoning about a specific change, ask here, and I will attempt to explain my choices. Thanks for an informative article! – Jonesey95 (talk) 23:39, 9 March 2020 (UTC)
Jonesey95, I finished clarifying, rewriting and removing per all the tags in the article.
  1. I don't like the old title, but the newer one also didn't fit. I've changed it again, splitting the subsection into two.
  2. Yes? Which one do you think is the most akward?
  3. Yes, I believe this was an essential paragraph, but definitely in the wrong place. I put it in the merged 'measures of climate sensitivity' paragraph
  4. I've tried to clarify with introction and extra sentence. The eECS is the standard way of approximating ECS, so it is essential in my opinion. I agree I wrote it down horribly before.
  5. I've tried to make clear that this is per radiative forcing they cause.
  6. That's fair I think
  7. I think I solved most of them adequately.
  8. I've opted not to provide his 1984 paper. It would be five your after the Charney report that his paper got published, so I reckoned it would only cause confusion.
Thanks again for doing such a thorough copy-edit. I didn't really believe this article could be made this accesible. Undoubtedly, there are still things that can improve, but I'm happy with it now. Femke Nijsse (talk) 17:27, 14 March 2020 (UTC)

It may be more meaningful to readers to also include ECS for land and for water as well as just the mean

ECS and TCS can be confusing to general readers. The mean temperature is useful as an index of general warming, but the ECS for land is more relevant to people's experiences. These are available [1].

It may help to include a section which addresses this, and gives some typical values.

I have not yet examined the IPCC AR6 WG1 report to see if they say anything about these.

EcoQuant (talk) 22:15, 13 August 2021 (UTC)

Is this comment still relevant, User:Empirical bayesian and others? I see it hasn't been addressed in the last two years, not sure if it was overlooked or landed in the too difficult basket. (I don't understand this topic enough to respond to the comment) EMsmile (talk) 20:35, 20 September 2023 (UTC)

References

  1. ^ Schmittner, Andreas, Nathan M. Urban, Jeremy D. Shakun, Natalie M. Mahowald, Peter U. Clark, Patrick J. Bartlein, Alan C. Mix, and Antoni Rosell-Melé. "Climate sensitivity estimated from temperature reconstructions of the Last Glacial Maximum." Science 334, no. 6061 (2011): 1385-1388.

See also section?

I feel (but am not sure) that the two concepts climate risk and climate change scenario are somewhat related to climate sensitivity. As they were not yet mentioned in the main text, I put them under "See also" for now. Or perhaps I am mistaken and they have nothing to do with this? EMsmile (talk) 20:38, 20 September 2023 (UTC)

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