Talk:Climate change feedbacks

Some work done on the lead

I've just done some work on the lead:

• I used the table of content to come up with a summarised list of positive and negative feedbacks but it made me realised how poor some of the section headings, ordering and structure were. I've tried to make some quick changes (knowing that people already look at this article now for information) but I know this will require further work.
• I also tried to put them a bit more in order of "most important" to "least important". Please help if I got this wrong.
• Also, the information about the blackbody radiation is confusing. Femke had added: "it is typically not considered a feedback" whereas later in the main text we do list it under negative feedback and it says there: "It is called the Planck response, and sometimes considered a negative feedback". Here on the talk page, user InformationToKnowledge had quoted "Outgoing longwave radiation acts as the main major negative feedback, as hot things radiate more heat away". So I am confused now.
• Question: should we mention something about the lapse rate in the lead? Note: I have now moved that into a new section for things that can be either positive or negative. User:Sjsmith757 can you help further with the info on the lapse rate? EMsmile (talk) 22:06, 25 July 2023 (UTC)

@User:Bikesrcool or anyone else: could you help with cleaning up the content about blackbody radiation? Or has this already been sorted out? I see in the lead This blackbody radiation or Planck response has been identified as "the most fundamental feedback in the climate system" - do we need to provide both those terms or would one be sufficient? Are they the same thing? EMsmile (talk) 21:47, 23 January 2024 (UTC)

"Mathematical formulation" section

@Bikesrcool: WP:ONEDOWN is a general principle that I think editors in the climate change area intuitively follow, as we know we are communicating with the general public. Separately, I think the formulation itself is so similar to the early textual description, that a formulation doesn't really add anything more to the reader's knowledge. For these reasons, a "Mathematical formulation" section is not appropriate so early--and prominently--in the article. If it's retained in the article, I definitely think it should be moved down, before "See also" because all previous sections are meant for a lay audience and their likely concerns. I hope you'll consider these constructive remarks. —RCraig09 (talk) 04:54, 19 August 2023 (UTC)

Thanks for the constructive comment. The section has been moved to later for now. I feel the math is stripped down to a bare minimum while still succinctly linking the connected concepts of energy imbalance, forcings, and feedbacks. If placed earlier, the math complements the other introductory info in that sense, and would - in my opinion - be more logically situated before diving into the more gritty details of each individual component. Please also consider that highlighting a bit of low-level math can serve as a way of communicating the rigorous foundations of the science with the general public. Bikesrcool (talk) 15:40, 19 August 2023 (UTC)

@Bikesrcool: Thank you for being open minded. Discussions like recent ones at Talk:Greenhouse effect are in line with a community approach that the techy stuff should be placed lower in articles or in separate subsidiary articles. Generally, the presence of mathematical discussion might suggest credibility of the subject to the lay reader; however, a stripped-down version of the math that is just an alternative expression of the already-existing textual description, tends to suggest we are straining to "sell" a subject's credibility. (Conversely, going beyond the stripped-down version would be too techy for 99% of readers here.) In the present case, I think we've arrived at a good solution. —RCraig09 (talk) 15:57, 19 August 2023 (UTC)

I also have my doubts about this section. The formulae initially seem offputting but when reading through the section, I can see that they are very simple. Just putting the words into an equation. And then I wonder what's the point in even having them. I guess it's OK that they're so far down the article now but I would even be inclined to take the equations out and just leave the words (and in this case moving the section back towards the beginning again). I came to this article again because Bikesrcool was pondering over putting the same equations also at radiative forcing, see talk page there. EMsmile (talk) 21:43, 23 January 2024 (UTC)

Shouldn't the article title be "Climate change feedbacks", not "Climate change feedback"?

We aren't talking about a singular feedback. Even in our definitional sentence we begin by saying "Climate change feedbacks...". Sorry if this has been covered before, but it reads weird in the general climate change article as well, where climate forces are all plural except feedbacks. We have "aerosols", "clouds", "greenhouse gases", and then "climate change feedback". Any objection to doing a simple rename to this article? Efbrazil (talk) 15:49, 9 February 2024 (UTC)

• Agree. I'm OK either way, but the plural does inherently convey more information, instantly. —RCraig09 (talk) 21:48, 9 February 2024 (UTC)
• Strong support. I agree with you. EMsmile (talk) 14:31, 10 February 2024 (UTC)

Unclear sentence in the lead

Examples of some effects of global warming that can amplify (positive feedbacks) or reduce (negative feedbacks) global warming Observations and modeling studies indicate that there is a net positive feedback to Earth's current global warming.

I am trying to improve the reading ease of the lead but this sentence really baffles me, it seems messed up: These are arctic methane release from thawing permafrost, peat bogs and hydrates, abrupt increases in atmospheric methane, decomposition, peat decomposition, rainforest drying, forest fires, desertification. Seems like a messy list. Also, the paragraph in the lead about positive feedbacks (currently the second one) should line up better with the graphic on the right. I suggest to use the same ordering, and ensure the most important one is first (?). EMsmile (talk) 23:10, 15 March 2024 (UTC)

Update: this has been addressed in the meantime. EMsmile (talk) 21:09, 29 April 2024 (UTC)

References

Shouldn't the lead be changed to clarify that the total (net) feedback is negative when accounting for ALL feedbacks?

Quotation taken from top of page 978 AR6 WGI Chapter7 (and see table 7.10 at bottom of same page): "It is virtually certain that the net climate feedback is negative, primarily due to the Planck temperature response, indicating that climate acts to stabilize in response to radiative forcing imposed to the system. Supported by the level of confidence associated with the individual feedbacks, it is also virtually certain that the sum of the non-Planck feedbacks is positive. Based on Table 7.10 these climate feedbacks amplify the Planck temperature response by about 2.8 [1.9 to 5.9] times."

Likewise quoting from page 96 AR6 WGI Technical Summary (and see accompanying figure TS.17): "The combined effect of all known radiative feedbacks (physical, biogeophysical, and non-CO2 biogeochemical) is to amplify the base climate response (in the absence of feedbacks), also known as the Planck temperature response (virtually certain). Combining these feedbacks with the Planck response, the net climate feedback parameter is assessed to be –1.16 [–1.81 to –0.51] W m –2 °C –1 , which is slightly less negative than that inferred from the overall ECS assessment."

Could a simplified version of the Chapter 7 quotation replace the one now at the end of the lead?: It is virtually certain that the net climate feedback is currently negative and thus stabilizes climate over time, primarily due to Earth's blackbody radiation response. It is also virtually certain that the sum of all other feedbacks is positive and causes amplification of global warming. Bikesrcool (talk) 05:54, 14 April 2024 (UTC)

Could you make it more understandable for lay persons (given that it's the lead)? I don't really understand what is meant with "that the net climate feedback is currently negative" and "the sum of all other feedbacks". Perhaps you could be more explicit or give examples or use "in other words, xxx". Sometimes it even works to ask Chat-GPT how something could be said simpler. For example the first quote that you mentioned (p. 978) could be simplified as follows, Chat-GPT suggests "The overall effect of climate feedback is likely to be negative, mainly because of the Planck temperature response, meaning that the climate tends to stabilize when there's extra heat added to the system." I am not saying this is necessarily right or better, it's just something worth using for inspiration. Also given that the IPCC reports are not compatibly licenced so have to be paraphrased in any case. EMsmile (talk) 12:59, 14 April 2024 (UTC)

This is great input, thanks Bikesrcool! I tried to boil down that excellent synopsis on page 95 of AR6 WG1. As EMsmile says, best to avoid words like Planck response in the lead. Take a look and see if what I wrote works for you. Efbrazil (talk) 18:06, 14 April 2024 (UTC)

Ping to RCraig09, who has put in a lot of the content characterizing feedbacks as positive. Make sure you read that page of the IPCC report. The key point as I understand things is that feedbacks are net negative right now, but will become less negative as an effect of emissions continuing and/or time going by. Efbrazil (talk) 18:26, 14 April 2024 (UTC)

I don't think I provided the original motivation to even mention net positive vs. net negative feedback. I followed someone else's lead in even mentioning it, with my edit comment saying the content was added to avoid the inference expressed by another editor that positive and negative were balanced (I merely copied content from the lead text and placed it into the lead image caption; that particular sentence has just been deleted from the lead text.) The current lead image caption refers to AR5] (2014), which states on p. 82: "Therefore, there is high confidence that the net feedback is positive and the black body response of the climate to a forcing will therefore be amplified." I haven't studied AR6's apparent reversal of that conclusion—if they're talking about exactly the same issue. At this point, I think it wise to simply delete that sentence from the lead image caption until more knowledgeable editors have resolved the issue. —RCraig09 (talk) 19:21, 14 April 2024 (UTC)

Yeah, OK, let's go all the way to the top then and ask Femke :) Efbrazil (talk) 22:02, 14 April 2024 (UTC)

We should offer a consulting fee. :) —RCraig09 (talk) 22:18, 14 April 2024 (UTC)

With my mathematician's hat on: the Planck response is not a feedback in the mathematical sense. A feedback is the amplification of an initial response, and the Planck response is that initial response / reference system (https://www.atmos.albany.edu/daes/atmclasses/atm551/OtherReadingMaterials/Roe_AnnuRevEarth2009.pdf). So the AR6 was a bit sloppy in their wording; perhaps written by physicists rather than by mathematicians. We also repeat this misclassification in our lead. —Femke 🐦 (talk) 06:14, 15 April 2024 (UTC)

My recommendation is to defer to AR6 and the large body of supporting research which treats the generic Planck response and other Earth-specific feedbacks in a similar manner. To RCraig's comment: I understand there is no basic change between the technical conclusions of AR5 and AR6... just difference nuance/emphasis in the wording. To Femke's comment: Feedbacks can be talked about in different ways, that is why the math accompanying there scientific/physics definition is unavoidable and necessary to reign in other possible wanderings. The brief math formulation section of this article aligns IMO with the math/physics discussion of AR5, AR6, and the majority of other scientific literature that I've seen. These show that the Planck response is a feedback in the most fundamental mathematical sense as defined by the broader scientific community. As such, it is also often recognized to be a special response being ONLY a function of temperature. I am satisfied with the changes made by Efbrazil and RCraig to my post to this point and thank them. Bikesrcool (talk) 13:48, 15 April 2024 (UTC)

I'm not sure that's correct. AR6 usually talks about the Planck response, rather than the Planck feedback. In some graphs they have the Plack response plotted separately from the radiative feedbacks (for instance 7.20), implying that it's not a radiative feedback. They also state: "The combined effect of all known radiative feedbacks (physical, biogeophysical, and non-CO2 biogeochemical) is to amplify the base climate response, also known as the Planck temperature response (virtually certain)." Overall, they're a bit messy in their wording here. In literature on climate sensitivity (my former field), you often see the statement like "Without feedbacks, you'd have 1 degree of warming per doubling of CO2". That would be a non-sensical statement if the Planck response is considered a feedback. We could add the different perspectives to the article in footnotes, and use the more generic "Planck response" in our prose? —Femke 🐦 (talk) 15:29, 15 April 2024 (UTC)

What's interesting for the lead is whether the climate response to a linear increase in greenhouse gas emissions going forward is going to accelerate or decelerate, or whether the geographic locations of amplified warming will change at all. That means taking everything into account as much as possible- the carbon cycle, Planck response, and maybe even socioeconomic responses. Do we have something definitive on the holistic issue?

Whether the Planck response is defined as a feedback or not can go in the definition section along with whether the carbon cycle is considered a feedback. It sounds like we should both-sides those issues since there are references in either direction. However, for general interest on the topic, I think the right thing to do is mention everything, because the holistic picture is what matters in the end. Efbrazil (talk) 16:32, 15 April 2024 (UTC)

The carbon cycle is a feedback, it's just in a different categories of feedbacks than those we discuss when we talk about equilibrium climate sensitivity. Okay for me to change to Planck response? And write something about the Planck response sometimes being considered a feedback in a footnote? —Femke 🐦 (talk) 16:39, 15 April 2024 (UTC)

Obviously we'd love your help here, but I think the important thing we don't understand is the holistic effect. I'd love a paragraph in the lead saying "if GGE continue at their current rate, this is how the climate will change up to 2C, and this is what will happen up to 3C". I know that's a very difficult question to answer, which is why a lot of reports fall back to parsing individual components of the response instead of the overall response.

A lead that is instead focused on enumerating all possible feedbacks and saying what is or is not technically a feedback is a lot less interesting imho. As for the definitional issue, the carbon cycle is a "climate change feedback" if you are talking about the response to GGE, but if you are talking about feedbacks strictly in the context of given greenhouse gas levels (as AR4+ do with RCPs), then it is not. Efbrazil (talk) 16:52, 15 April 2024 (UTC)

Yeah, I agree definitions are not great in the lead. I think a footnote in the lead may work however. You think that's too much too? —Femke 🐦 (talk) 17:52, 15 April 2024 (UTC)

Sure, a footnote is good, plus probably some text in the definition and terminology section to back it up. Efbrazil (talk) 20:09, 15 April 2024 (UTC)

Also, it occurs to me that if feedbacks that included the Planck response as a feedback were net positive, then we could be talking about a runaway greenhouse effect, which nobody is predicting. Is that correct, or does a positive feedback value just mean warming would be amplified? Maybe a feedback value of over 1.0 = runaway greenhouse effect? The Internet is not helping with my blue sky questioning... Efbrazil (talk) 20:14, 15 April 2024 (UTC)

Yeah, I am also concerned about risk that a casual reader of the lead might associate a statement of net positive feedback with tipping or runaway. Whether the Planck response is properly classified as a feedback seems to me like a distraction in the bigger scope of the article, but I guess one could add a section acknowledging this nuance later down. Still when I think of perturbation theory, the two basic elements that I associate with it are just forcings and feedbacks... or forcings and responses. Thanks for all the great discussion of this topic. Bikesrcool (talk) 15:19, 16 April 2024 (UTC)

Good! I just did a fairly substantive edit pass on the last 3 paragraphs of the lead. Hopefully things are approaching OK. Efbrazil (talk) 17:43, 16 April 2024 (UTC)

I've just made some further tweaks to the lead to make it easier to understand. I hope I didn't change the meaning by mistake. There are still two sentences remaining which I find a bit hard to understand: Carbon cycle feedbacks are negative as carbon uptake increases when atmospheric concentrations increase. However, higher temperatures and saturation of carbon sinks will decrease that effect. (perhaps an example could help to clarify this? Sounds very abstract like this.).

And the lead length is a bit on the short side (344 words) but I guess that's OK as the overall article length is also short-ish (29 kB). EMsmile (talk) 21:09, 29 April 2024 (UTC)

It turns out that I never put this page on my watchlist, and had missed this discussion entirely. So, it's been quite a surprise for me when Efbrazil had reverted two paragraphs of my changes to the lead with the summary of: The last sentence was a clear run on sentence with bad readability. The Planck response is not a feedback and the IPCC explicitly says feedbacks will increase for the remainder of the century. Feedbacks are not "primarily estimated through models". The lead that was there was arrived at through extensive discussion- go slow on edits or open talk discussion please.

This is the comparison of the two versions.

Current wording

The reverted paragraphs

....The main positive feedback is that warming increases the amount of atmospheric water vapor, which is a powerful greenhouse gas.[5] Another positive feedback is the loss of reflective snow and ice cover. Positive carbon cycle feedbacks occur when organic matter burns or decays, releasing CO2 back into the atmosphere. Loss of organic matter can happen through rainforest drying, forest fires, and desertification. Methane can also be released into the atmosphere by thawing permafrost. The main cooling effect is called the Planck response, which comes from the Stefan–Boltzmann law. It states that the total energy radiated per unit surface area per unit time is directly proportional to the fourth power of the black body's temperature. The carbon cycle acts a negative feedback as it absorbs more than half of CO2 emissions every year. Atmospheric CO2 gets absorbed into rocks and into plants. It also gets dissolved in the ocean where it leads to ocean acidification. There are several types feedbacks: physical feedbacks, biological feedbacks and carbon cycle feedbacks. Calculations can give different results depending on the time frame and location that is used. Carbon cycle feedbacks are negative, which means that as atmospheric concentrations increase, carbon uptake also increases. However, higher temperatures and saturation of carbon sinks decrease that negative feedback effect. Overall feedbacks are expected to trend in a positive direction for the near future, though the Planck response will become increasingly negative as the planet warms.[6]: 94–95  There is no threat of a runaway greenhouse effect from current climate change.

....Feedbacks are generally divided into purely physical and partially biological (i.e. biogeophysical and biogeochemical.) The former include cloud feedback, ice-albedo feedback, Planck response feedback as well as the lapse rate and water vapor feedbacks. The latter mostly consist of feedbacks associated with the carbon sinks and the carbon cycle. Sometimes, feedbacks associated with the ice sheets are treated separately from either, because it takes multiple centuries before they become apparent, whereas the others have a substantial role within decades. Feedback strengths and relationships are primarily estimated through global climate models, with their estimates calibrated against observational data whenever possible. "Fine-scale" modelling devoted to specific processes also exists, and has been used more widely starting from 2010s. The overall sum of climate feedbacks is negative, meaning that they make the warming slower than it would be otherwise. It also means that runaway greenhouse effect effectively cannot occur due to anthropogenic climate change. This is largely because of the Planck rate negative feedback, which is several times larger than any other singular feedback. Additionally, the carbon cycle already absorbs a little over half of annual CO2 emissions, and its ability to do so scales almost in proportion to emissions. However, as the warming increases, it amplifies positive feedbacks - like the ice-albedo feedback and soil carbon feedback, or the various feedbacks which increase atmospheric methane concentrations - more than the negative ones, so the warming is slowed less than it would have been at a cooler initial state.

Now...

and the IPCC explicitly says feedbacks will increase for the remainder of the century. - Which is exactly what the last sentence was meant to say - the one which you concluded lacked readability.

The IPCC also explicitly says that the sum of all feedbacks is negative, yet as already pointed out by Bikesarecool above, this is not currently mentioned at all. And speaking of things which were explicitly mentioned by the IPCC...

Feedbacks are not "primarily estimated through models". - Wanna bet?

Up until AR5, process understanding and quantification of feedback mechanisms were based primarily on global climate models. Since AR5, the scientific community has undertaken a wealth of alternative approaches, including observational and fine-scale modelling approaches. - AR6, WG1, CH7, 967

The Planck response is not a feedback - and this is where the discussion above gets really confusing. So, Bikesarecool has already provided an IPCC quote where it is considered a feedback. If necessary, I can provide another. EDIT: There it is.

The Planck response represents the additional thermal or longwave (LW) emission to space arising from vertically uniform warming of the surface and the atmosphere. The Planck response αP, often called the Planck feedback, plays a fundamental stabilizing role in Earth’s climate and has a value that is strongly negative: a warmer planet radiates more energy to space. - AR6, WG1, CH7, 968

Yet, apparently, the discussion so far has opted to believe that the IPCC as a whole has made a mistake, based on...Femke's individual opinion and an Annual Reviews article from 2009? Sure, this here

It is also worth mentioning that what even counts as a feedback depends on the definition of the reference system. For example, the Stefan-Boltzman relation is often described as a negative climate feedback acting to regulate temperature anomalies. In fact, for a blackbody planet, which is the simplest imaginable reference system for the climate that is still meaningful, the Stefan-Boltzman relation is part of the reference system and therefore not a feedback at all. These are not semantic or esoteric issues—the quantitative intercomparison of different feedbacks can be done only when the reference system is defined and held constant

Is interesting. Should this, written by just one professor, be given credence over the wording of the world's premier scientific body, over a decade later? I doubt it. Moreover, here is something else from the earlier discussion: (quote template keeps bugging out here, for some reason.)

"Also, it occurs to me that if feedbacks that included the Planck response as a feedback were net positive, then we could be talking about a runaway greenhouse effect, which nobody is predicting. Is that correct, or does a positive feedback value just mean warming would be amplified? Maybe a feedback value of over 1.0 = runaway greenhouse effect?..."

I believe that (the bolded part) actually is the case? I would quote myself from a discussion we had here last year (now archived):

According to the leading expert on climate feedback loops and tipping points, Dr. Adam Armstrong McKay (the lead author of last year's Science assessment of tipping points):

"Outgoing longwave radiation acts as the main major negative feedback, as hot things radiate more heat away. Positive feedbacks do not inevitably lead to runaway warming, as negative feedbacks will eventually counter them – if there were no negative feedbacks Earth would have become as hot as Venus long ago."

So, it probably shouldn't matter given the opinion of the IPCC alone, but the lead author of this paper we cite very extensively, and almost certainly one of the top 5 experts on the subject worldwide, also happens to describe the Planck response/blackbody radiation as a feedback. Are we going to argue against this too? (Trivia: I think he and Femke might be at the same research institution, so there is conceivably a chance they could talk this over in person?) InformationToKnowledge (talk) 12:34, 15 May 2024 (UTC)

P.S. This isn't related to the reverted paragraphs, but I might as well address this matter now anyway:

What's interesting for the lead is whether the climate response to a linear increase in greenhouse gas emissions going forward is going to accelerate or decelerate, or whether the geographic locations of amplified warming will change at all. - I have already answered this question in the lead of Causes of climate change (which apparently wasn't read very closely by anyone here?)

The warming from the greenhouse effect has a logarithmic relationship with the concentration of greenhouse gases. This means that every additional fraction of CO₂ and the other greenhouse gases in the atmosphere has a slightly smaller warming effect than the fractions before it as the total concentration increases. However, only around half of CO₂ emissions continually reside in the atmosphere in the first place, as the other half is quickly absorbed by carbon sinks in the land and oceans.

As the warming from CO₂ increases, carbon sinks absorb a smaller fraction of total emissions, while the "fast" climate change feedbacks amplify greenhouse gas warming. Thus, both effects are considered to each other out, and the warming from each unit of CO₂ emitted by humans increases temperature in linear proportion to the total amount of emissions.

This is based on the following IPCC paragraphs:

As cumulative emissions increase, weakening land and ocean carbon sinks increase the airborne fraction of CO2 emissions (see Figure 5.25), but each unit increase in atmospheric CO2 has a smaller effect on global temperature owing to the logarithmic relationship between CO2 and its radiative forcing (Matthews et al., 2009; Etminan et al., 2016). At high values of cumulative emissions, some models simulate less warming per unit CO2 emitted, suggesting that the saturation of CO2 radiative forcing becomes more important than the effect of weakened carbon sinks (Herrington and Zickfeld, 2014; Leduc et al., 2015). The behaviour of carbon sinks at high emissions levels remains uncertain, as models used to assess the limits of the TCRE show a large spread in net land carbon balance (Section 5.4.5), and most estimates did not include the effect of permafrost carbon feedbacks (Sections 5.5.1.2.3 and 5.4). The latter would tend to further increase the airborne fraction at high cumulative emissions levels, and could therefore extend the window of linearity to higher total amounts of emissions (MacDougall et al., 2015). Leduc et al. (2016) suggested further that a declining strength of snow and sea ice feedbacks in a warmer world would also contribute to a smaller TCRE at high amounts of cumulative emissions. However, Tokarska et al. (2016) suggested that a large decrease in TCRE for high cumulative emissions is only associated with some EMICs; in the four ESMs analysed in their study, the TCRE remained approximately constant up to 5000 PgC, owing to stronger declines in the efficiency of ocean heat uptake in ESMs compared to EMICs.

Overall, there is high agreement between multiple lines of evidence (robust evidence) resulting in high confidence that TCRE remains constant for the domain of increasing cumulative CO2 emissions until at least 1500 PgC, with medium confidence of it remaining constant up to 3000 PgC because of less agreement across available lines of evidence. - AR6, WG1, CH5, 746

TLDR; climate response will remain linear for the foreseeable future, and once it is no longer linear, it is more likely to decelerate rather than accelerate. InformationToKnowledge (talk) 12:37, 15 May 2024 (UTC)

P.P.S. For all of the fairly dense and arguably not-layman-relevant discussion that dominates our article on the greenhouse effect - with all its mentions of energy flux and top-of-the-atmosphere and what not - it does not seem to say anything about its logarithmic nature at all. Perhaps it is time to finally rectify this omission? If so, would we explain the logarithmic growth as a property caused by the Planck response (and correspondingly mention it here as well?), or is there some other factor? InformationToKnowledge (talk) 12:44, 15 May 2024 (UTC)

No objections, but I think that's a separate discussion best raised on that talk page there. Efbrazil (talk) 18:36, 15 May 2024 (UTC)

Thanks for opening this discussion. The comment reverting that edit area had to be very abbreviated as per comment lengths.

As for saying feedbacks are "primarily estimated through models": The issue is that's wording that climate deniers use. Their argument is that all this climate stuff is just apocalypic modeling by scientists wanting funding or fame and not a reflection of the real world. Think of the middle school education person encountering this article. We need to first establish the real world data and the physical grounding for all we're saying. It is fine to say that models built on top of those fundamentals are how we estimate feedback outcomes, but only later. So it's a minor issue, but I'd rather the lead focus on fundamentals.

As for the Planck response being a feedback: There are sources in the IPCC going either way on the issue, so we should not be stating that the Planck response is a feedback. Let me know if you disagree and I can dig up some IPCC talk that reflects the alternate view that backs what Femke said. The lead text that I reverted to split the difference to get to consensus. It talks about Planck response but never says it is a feedback, and I think we need to stick with that wording unless there is consensus to the contrary.

You do a great job as usual of highlighting the issues that caused the lead text that's there now to end fairly ambiguously about which direction feedbacks are headed. I am certainly happy with adding a well sourced summary sentence saying that climate response will remain linear for the foreseeable future. I was looking for something like that myself as you could tell in quoting me up above. Just make sure any claims you make are well sourced.

To be clear, my reverting your text wasn't about saying it was all wrong, only that I had certain disagreements. If you make changes more incrementally it's better for everyone, because that way each change can be reviewed in isolation. If there's a big pivot or issue you want to address then the talk page is a great place to do it. Efbrazil (talk) 18:33, 15 May 2024 (UTC)

Let me know if you disagree and I can dig up some IPCC talk that reflects the alternate view that backs what Femke said. - Please do. Having said that, this is secondary to the question at the top of this section - about the direction of the net sum of feedbacks. As you might have noticed, I included another prominent reference which says that the net feedback is negative, but I don't know if this is going to make a difference. If some editors here already find the IPCC text "ambiguous", would a single paper on top of it (even from Nature Geoscience) matter? Would 3, 5, or 10 more matter?

Having said that, I am also open to the argument that the only thing we really need to say in the lead is about the (lack of) direction in the net climate response to emissions (which doesn't mean that the rate of observed warming will stay linear, since a massive increase in emissions has already happened yet wouldn't be fully felt until the next couple of decades.) Would that also mean that we should use a similar wording in the lead here, at Causes of climate change, at greenhouse effect and perhaps in the lead of other related articles like climate sensitivity?

As for saying feedbacks are "primarily estimated through models": The issue is that's wording that climate deniers use. Hmm, my primary impression to date has been the opposite - stupid claims on various social media that "[feedback which has been known for many decades] isn't in the models and so there'll "actually" be this much more warming than what the IPCC says." I noticed that the individual feedback sub-sections already had little "This feedback is in the models" disclaimers (which I tried to rework into stronger and more specific sentences), so at least some editors are clearly aware of this issue. I wonder if anyone else wants to weigh in? InformationToKnowledge (talk) 02:43, 16 May 2024 (UTC)

A few references to consider. This text says that net feedbacks are heading in a positive direction:

IPCC AR6 WG1 Technical Summary 2021, p. 93: Feedback processes are expected to become more positive overall (more amplifying of global surface temperature changes) on multi-decadal time scales as the spatial pattern of surface warming evolves and global surface temperature increases.

Regarding whether the Planck response is a feedback, here is text that says Planck response is a base climate response and not a feedback (there are counterexamples as well):

IPCC AR6 WG1 Technical Summary 2021, p. 95: The combined effect of all known radiative feedbacks (physical, biogeophysical, and non-CO2 biogeochemical) is to amplify the base climate response (in the absence of feedbacks), also known as the Planck temperature response.

In general, Planck response is only mentioned very sparingly in the report. Whether it is considered a feedback impacts how to interpret the IPCC report and how to compose the lead. Does that page 93 text include Planck response when saying "more positive overall"? That's where the ambiguity comes in. Efbrazil (talk) 15:14, 16 May 2024 (UTC)

Excuuuuse me... Let's step back. Almost ~5000 words have been invested here, trying to un-ambiguate what is an ambiguous term. Maybe it would be best to avoid broad statements in the lead (about net positive vs net negative), and instead explain the ambiguity in a dedicated section lower in the article. —RCraig09 (talk) 16:21, 16 May 2024 (UTC)

That's the current state of the article, more or less. I think I2K is trying for clarity, which would be great. The easiest claim to make is that the IPCC is a hot mess when it comes to this issue. AR6 WG1 TS Page 93 has two declarative statements defining what a feedback is and they are completely at odds with each other. Efbrazil (talk) 19:31, 16 May 2024 (UTC)

I think there is no consensus in this discussion to remove the key statement about the net effect of feedbacks from the text of multiple articles. When there is disagreement we revert to the status quo ante. I don't think this article is neutral without this statement in the lead. Page 93 and 94 of the TS don't seem internally inconsistent. The net effect is mentioned implicitly on p93 one and explicilty on p94, in accordance with each other. —Femke 🐦 (talk) 18:43, 19 May 2024 (UTC)

Sorry, I had the page number wrong, it's page 95 of the TS, not page 93. The text there is confusing as it says the Planck response is not a feedback, but it is part of net feedbacks. Here's the word salad:

The combined effect of all known radiative feedbacks (physical, biogeophysical, and non-CO2 biogeochemical) is to amplify the base climate response (in the absence of feedbacks), also known as the Planck temperature response (virtually certain). Combining these feedbacks with the Planck response, the net climate feedback parameter is assessed to be –1.16 [–1.81 to –0.51] W m–2 °C–1, which is slightly less negative than that inferred from the overall ECS assessment. The combined water vapour and lapse rate feedback makes the largest single contribution to global warming, whereas the cloud feedback remains the largest contribution to overall uncertainty. Due to the state-dependence of feedbacks, as evidenced from paleoclimate observations and from models, the net feedback parameter will increase (become less negative) as global temperature increases. Furthermore, on long time scales the ice-sheet feedback parameter is very likely positive, promoting additional warming on millennial time scales as ice sheets come into equilibrium with the forcing.

The main point we could run with is that "the net feedback parameter will increase (become less negative) as global temperature increases". They explicitly say that includes Planck response. Efbrazil (talk) 22:05, 19 May 2024 (UTC)

Again, that was the exact purpose of the phrase you reverted as The last sentence was a clear run on sentence with bad readability.

You know, this one: However, as the warming increases, it amplifies positive feedbacks - like the ice-albedo feedback and soil carbon feedback, or the various feedbacks which increase atmospheric methane concentrations - more than the negative ones, so the warming is slowed less than it would have been at a cooler initial state.

OK, it probably was too complex and should have been split, but this is what it was meant to say (and while avoiding close paraphrasing.)

Anyway, here is something you should pay attention to. I have been in contact with Kevin Trenberth, a lead author of three IPCC reports, (you can double-check by asking @EMsmile) and he agrees that the net climate feedback is negative and it can only be considered positive when the Planck response is de-emphasized and moved into the background - which is an approach he dislikes.

Granted, this isn't very easy to summarize. After a couple of attempts, I got to a wording he thinks is "OK".

The overall sum of all climate feedbacks is negative, meaning that, for a warming climate, the warming is slower than it would be otherwise. This due to the strongly negative Planck radiative rate feedback, which is several times larger than any other singular feedback. In estimates where Planck rate response is described as part of the baseline climate system, the net sum of feedbacks is positive, but its stabilizing effect is still assumed implicitly.

You may think there is a way to improve this sentence structure, etc., but hopefully this settles the fundamental argument. InformationToKnowledge (talk) 12:26, 20 May 2024 (UTC)

Page 95 of the TS says that the Planck response is part of the climate feedback "parameter", which is also called the climate sensitivity parameter. It explicitly says this parameter is the sum of feedbacks and the Planck response. There is no contradiction there. It's just much easier to add these in an equation.

I object to the new text. Apart from calling something a feedback which the IPCC says isn't one, the word "otherwise" is describing a hypothetical with infinite warming. It doesn't make sense to compare it with that. I'm also not sure we should be using positive or negative here. There is no consistent Sign convention around the climate sensitivity/feedback parameter, even though the convention the IPCC use is more common. Better to describe the net effect as amplifying. —Femke 🐦 (talk) 16:10, 20 May 2024 (UTC)

I went through I2K's text again and tried to pull out some of the parts I think are good additions and also tried to factor in what femke is saying. Here is a cut at rewriting the last paragraph:

Calculating climate sensitivity requires accounting for the planck response, radiative feedbacks, and carbon cycle feedbacks. Overall, climate sensitivity is expected to increase in the near future, although there is no threat of a runaway greenhouse effect. Time frames and emission rates impact estimates. Feedbacks associated with ice sheets can take centuries, whereas the other feedbacks have a substantial role within decades. Carbon cycle feedbacks are negative in the short term because carbon uptake increases as atmospheric concentrations increase, but over the long term higher temperatures and carbon sink saturation are reducing that negative effect. Feedbacks can also result in localized differences, such as increased warming in locations with reduced snow and ice. Feedback strengths and relationships are estimated through global climate models, with their estimates calibrated against observational data whenever possible. Efbrazil (talk) 17:07, 20 May 2024 (UTC)

I'm mostly happy with this compromise. One thing: carbon feedbacks are climate system feedbacks. The grouping is usually physical vs carbon vs other biogeochemical. —Femke 🐦 (talk) 18:55, 20 May 2024 (UTC)

I changed the proposed text above to say "radiative feedbacks" instead of "climate system feedbacks"...Efbrazil (talk) 19:56, 20 May 2024 (UTC)

Change made. Since this is in the direction InformationToKnowledge wanted hopefully they can let it stick and maybe build on it. Efbrazil (talk) 16:46, 21 May 2024 (UTC)

OK, no, not really. I really didn't like that wording, particularly its sudden swerve into discussing climate sensitivity in terms that are confusing and of dubious accuracy. Then again, I didn't like the preceding wording either, but I simply had no idea what argument could possibly work after you have apparently decided that the IPCC is "is a hot mess when it comes to this issue" and disregarded the opinion of one of its past lead authors.

This week, I simply opted to contact the lead author of that chapter, Piers Forster. What he told me is that "If assessing feedbacks as a temperature change, you estimate the base temperature change with the Planck feedback then the other positive feedbacks amplify this". However, if feedbacks are assessed as differences in radiative forcing then the Planck temperature response is a feedback like any other. AR6 WG1 Chapter 7 estimates all the feedbacks in terms of radiative forcing differences, which is why it says that Planck response is a negative feedback.

Hopefully, we are not going to argue about the judgement of the lead author of the literal chapter on feedbacks. I have already applied its structure elsewhere in the article - same subheadings, adding radiative forcing values to every feedback sub-section, etc. With this subject clarified, I largely went back to my previous wording, although I did integrate some phrases from the Efbrazil's version (i.e. the explanation of how models and observations are used to estimate feedbacks.)

I made additional changes as well - simplified the explanation of the Planck feedback (how many readers want to see "fourth power" mentioned in the lead?), added the conspicuously missing cloud feedback, clarified that the main example of regional changes is the Arctic amplification, explained how CO₂ causes ocean acidification, etc.

I also removed the mention of chemical weathering (it is far too slow to have played any role in the changes to date) and desertification (there has been no net change to date and it's unclear if there will be in the future - I already quoted AR6 saying that in this discussion) to avoid providing them with disproportionate attention. InformationToKnowledge (talk) 11:45, 28 May 2024 (UTC)

The new lead is extremely long now. Can you bring it back to under 400 words? Agree that fourth power shouldn't be in the lead. —Femke 🐦 (talk) 16:11, 28 May 2024 (UTC)

Well, it's only 500. It probably looks extremely long because of the inaccessible rp style of citations and long words. The last paragraph is too long for useability. —Femke 🐦 (talk) 16:27, 28 May 2024 (UTC)

How about now? InformationToKnowledge (talk) 18:06, 28 May 2024 (UTC)

@Efbrazil Why do you keep weakening the phrasing in the lead about the ice sheet feedbacks? On page 967, WG1 Chapter 7 outright says Long-term feedbacks associated with ice sheets (Section 7.4.2.6) are relevant primarily after several centuries or more. "Primarily after" is a much stronger wording than "can take". InformationToKnowledge (talk) 19:31, 28 May 2024 (UTC)

We still don't have a citation for the sum of feedbacks being negative. The IPCC text says the opposite. If you want to use a different convention, you have to find a source that uses this convention. I would like to use the IPCC convention, and I don't believe there is a consensus against the IPCC here, so we should revert to status quo ante. —Femke 🐦 (talk) 19:56, 28 May 2024 (UTC)

I attempted to take an edit pass on what InformationToKnowledge wrote. I could go further but would need more time to do it and need to go now.

Regarding points above:

• @InformationToKnowledge: Saying when feedback effects become apparent is very different from saying when the feedbacks will have their primary effect.
• @Femke: The IPCC is declarative that feedbacks are net negative if the Planck response is included, saying "the net climate feedback parameter is assessed to be –1.16 [–1.81 to –0.51] W m–2 °C–1". It's also fairly obvious from this chart: https://www.ipcc.ch/report/ar6/wg1/downloads/figures/IPCC_AR6_WGI_TS_Figure_17.png Correct me if I'm wrong, but I think it all just boils down to a terminology debate as to whether the Planck response is a feedback. I'm neutral on the matter.

Efbrazil (talk) 20:38, 28 May 2024 (UTC)

The IPCC says that the feedback parameter, i.e. Planck + feedbacks, is negative (assuming you use their sign convention). The IPCC is also declarative that the net effect of the actual radiative feedbacks is amplifying in Chapter 7 (page 926). They say: The combined effect of all known radiative feedbacks (physical, biogeophysical, and non-CO2 biogeochemical) is to amplify the base climate response, also known as the Planck temperature response (virtually certain). If there is consensus among editors here to use a convention that Planck is a feedback, we need to use a different source than the IPCC, or only cite page 96, where they say something different to the rest of the report in the caption. All the other page numbers contradict what we now say. —Femke 🐦 (talk) 21:23, 28 May 2024 (UTC)

Would radiative feedbacks include land and ocean carbon response to increased CO2? The IPCC graphic describes that as the second largest negative feedback after Planck response. They separately call out land and ocean carbon response to climate, so I assume that would be the "radiative feedback", and that land and ocean carbon response to increased CO2 is not a radiative feedback.

Regardless, I think what people care about is the all inclusive "net climate feedback parameter". That's what impacts the important stuff, like climate sensitivity changes going forward and whether we could enter a runaway greenhouse effect. I'd be fine going back to not declaring what is or is not a feedback in the lead and instead defer that to the terminology section. Efbrazil (talk) 23:30, 28 May 2024 (UTC)

@Femke The IPCC is also declarative that the net effect of the actual radiative feedbacks is amplifying in Chapter 7 (page 926). Really?

Radiative feedbacks, particularly from clouds, are expected to become less negative (more amplifying) on multi-decadal time scales as the spatial pattern of surface warming evolves, leading to an ECS that is higher than was inferred in AR5 based on warming over the instrumental record. - Same page

They say - Yes, and Chapter 7's primary author already said that this text applies when feedbacks are treated as a modification of the base temperature change, but not when they are described as changes in radiative forcing. He also literally used the phrase "Planck feedback".

@Efbrazil Saying when feedback effects become apparent is very different from saying when the feedbacks will have their primary effect. - OK, then don't say "become apparent" (yes, I was the one who first used it) and write what their text actually intended to convey instead.

I also tried to make the lead consist of four paragraphs because according to @EMsmile, that should be the standard? However, I think the lead looks really good now with three (well done!), and I am not sure if there is anything important left for the fourth paragraph to cover. InformationToKnowledge (talk) 14:21, 29 May 2024 (UTC)

The guideline about lead length is MOS:LEADLENGTH. This article has roughly 4000 words, which means a lead of 2 to 3 paragraphs is recommended. I think we should go for 3 here. I'll disengage wrt to the actual discussion. It's all about convention and preference it seems. I prefer how we wrote in the old stable version, but I'm happy to move on elsewhere so that we don't waste more time. —Femke 🐦 (talk) 16:12, 29 May 2024 (UTC)

...I finished writing the fourth paragraph just before seeing this comment. The lead is still below 500 words, and I think the paragraph I added now contains important information. Maybe not so essential that it cannot be cut from the lead, but still fairly important.

And happy that we can at least move on from that argument!InformationToKnowledge (talk) 16:19, 29 May 2024 (UTC)

Thanks! I think we're getting close. I took an edit pass on that last paragraph and tried to fix up the text on ice sheet time frames. The connection between feedbacks and policy would be interesting to draw, and I expect it connects strongly on the issue of carbon offsets, but we weren't making those connections so I omitted the issue. It's not very interesting if the only real issue is the exact remaining carbon budget before hitting certain temperature levels. I do think that last paragraph is iffy in terms of importance as it's really just covering feedback uncertainty, and I don't know if that's worth an entire paragraph in the lead, although the areas of uncertainty are interesting in an academic context. Efbrazil (talk) 18:38, 29 May 2024 (UTC)

New lead graphic proposal

We could adapt this image to a compressed form that is good for smartphones / thumbnails: https://www.ipcc.ch/report/ar6/wg1/downloads/figures/IPCC_AR6_WGI_TS_Figure_17.png

Chart (b) of that image can be cut as the content is already represented in chart (a) and isn't very consequential. The naming is a torture though, so I'd rename the item from "Biophysical and non-CO2 biogeochemical" to the somewhat simpler "Non-CO2 biological".

It's annoying that they have "total" for climate system feedbacks but do not provide a total for carbon cycle feedbacks. I'd just leave out "total" as a result.

Charts (a) and (c) could then be combined as the x axis is the same.

Also, I'm not sure we should have the jargony "planck" in there, so maybe add a parenthetical explanation saying (thermal radiation).

Finally, there's the discussion up above that we should account for, namely that planck response is not technically a feedback and that the carbon cycle is part of the climate system. So that leaves something like this:

Title: Factors influencing climate sensitivity

Rows, where "Radiative feedbacks" and "Carbon cycle feedbacks" would just be headers with no data:

Planck (thermal radiation)

Radiative feedbacks

• Water vapor and lapse rate
• Surface albedo
• Clouds
• Non-CO2 biological

Carbon cycle feedbacks

• Land carbon response to CO2
• Ocean carbon response to CO2
• Land carbon response to climate
• Ocean carbon response to climate

Finally, for the X axis label, simply have 2 arrows pointing off center that say "Negative feedback" and "Positive feedback", like the top of the IPCC chart does. I don't see a point in articulating "Climate feedback parameter (WM-2 C-1)" and the numbers as those will mean nothing to people. The caption and graphic description can get into all that. The real point of the graphic is to highlight the major factors to consider. Efbrazil (talk) 23:33, 20 May 2024 (UTC)

July 2022+ feedbacks diagram

Oh, now I see. As I mentioned today on my User Talk Page, I'm willing to create charts of part (a) and of part (c) of TS-17 and can do so within days.

However, such a chart is much more techy than the July 2022+ conceptual diagram (at right) that's presently in the lead. The present diagram's common English language and color-coded areas are more readily understood by the lay audience for whose benefit this website exists. Quantification, bar charts, confidence intervals / error bars, and explanations of "feedback parameters" W/(m^2*°C) can go lower in the article, possibly as high as the /* Physical feedbacks */ section. Also, the controversy of whether Planck is truly considered a feedback, and the WP:SYNTH issue of combining (a) and (c) in the same diagram, further argues against such detailed quantitative portrayals in the introduction. —RCraig09 (talk) 03:58, 21 May 2024 (UTC)

I think the goal of the graphic should be "best of both". In particular, a new graphic could fix these issues with the current flowchart:

• The text is not legible on smartphone or thumbnail, which I think is critical for a lead image. That's all the vast majority of our users will ever see.
• Information is not presented visually to show the magnitude of the feedback, it's just arrows and text.
• Permafrost methane is a neglible factor, not even warranting a bar of its own on the IPCC chart, but it gets prominent placement in the flowchart.

There are some aspects of the flowchart that should be carried forward, such as removing jargon from labels and maybe keeping the arrows to "greenhouse gases" and "global warming" at the top. It will be an iterative process to get it right. I have a fuzzy vision for what it should look like and could take it on if you don't want to. It's possible it won't work out or people will complain about WP:SYNTH, but the final image should be much more grounded that what is there now. Efbrazil (talk) 16:26, 21 May 2024 (UTC)

• Even on my cheapo 2.5-inch wide iPhone screen, the flowchart text is readable, and definitely easy to read when held in landscape orientation.
• Text and arrows do show related concepts visually.
• Permafrost methane was included in flowchart because of wide coverage in sources; it seems to be shown in the second-from-bottom bar of the IPCC chart.

+ The main substantive issue is whether a lead image in a layman's encyclopedia should show concepts or detailed techy magnitudes. (Aside: the detailed magnitudes here have substantial error ranges that either confuse laymen or can make them question the science itself.)

+ I'll proceed with a first bar-chart version combining (a) and (c) minus Planck, hopefully finishing within 24 to 36 hours, strongly urging it is proper in the /* Physical feedbacks */ section but not the lead. —RCraig09 (talk) 17:34, 21 May 2024 (UTC)

If you're happy to do the work of the new graphic, I'm happy to step back and see what happens.

I just checked the existing graphic on iphone and the fonts are entirely illegible in the wikipedia app. The font size on page is about the same as the text in the image that says "amplify warming" and "reduce warming", so that should be the minimum font size for anything important in the image.

Please don't subtract planck, it's key to providing a good overview.

Please also keep an open mind about dumping the current image as you're doing the work. Seeing visually how important feedbacks are with real data matters. Efbrazil (talk) 18:49, 21 May 2024 (UTC)

20240522 Climate change feedbacks

— Version 1 is uploaded 22 May. The different processes are all very techy and need external explanation, making it unsuitable for a lead graphic in a layman's encyclopedia article. I've de-emphasized the confidence intervals for a similar reason.
— Graphically, I can now see how I could compress the actual chart area horizontally a bit (the large blue and read areas), so the font-height-to-image-width ratio is larger (see ), though that would make the graphic occupy more vertical space in articles for a predetermined pixel width. Since that change involves a non-trivial amount of work, I will wait until any substantive issues are resolved.
— I've just downloaded the Wikipedia app. The above flowchart is definitely readable in landscape orientation on my 2.5x4-inch screen, even moreso if the viewers spread their fingertips. —RCraig09 (talk) 16:03, 22 May 2024 (UTC)

It's a start, but you seem dead set against replacing the lead graphic. I think we are talking past each other at this point. I have no no idea how you are getting visible text on a smartphone. Pinch zoom doesn't work in the app until you tap into the image, for what it's worth. The larger point is that all that shouldn't be required for a lead image. I'll see if I can get something that I think would work as a lead image, and I'll screenshot my iphone so the issue with the current graphic is more clear. If you can't see the problems with what we have now then you can't fix them. Efbrazil (talk) 18:19, 22 May 2024 (UTC)

Since "xxx feedback" is an abstraction, it's difficult to conceive a suitable lead image that doesn't depend on words, which represent concepts. You've mentioned that "real data" is important; however it's important to scientists and geeks but not to laymen on first exposure to the concept. (Placing techy terms in a larger font doesn't make them easier to understand.) Separately, font-size-compared-to-article-text-size is aspirational and not a rule, so a 2022 flowchart that has colored groups of feedback types instantly conveys the basic concept; for the genuinely curious to click and finger-spread to magnify small-but-legible details is not an unreasonable ~burden. I'd be interested in hearing creative new ideas, but a conceptual flowchart's cause-and-effect relations seems the go-to solution. A quantitative tech-jargon bar chart can be presented and explained lower in the article. —RCraig09 (talk) 20:14, 22 May 2024 (UTC)

+ A major change to the bar chart would be to narrow the width of the chart area, and increase the height of each bar so that two rows of larger text would be associated with each bar. This change would increase the vertical space occupied in the article, however. —RCraig09 (talk) 20:20, 22 May 2024 (UTC)

Yeah, those are all good points. Two rows of text could help to dejargonize, although the IPCC categorization is less than helpful. Why did they have to group water vapor with lapse rate in particular? They don't seem related and are complicated to explain separately, much less together.

I like how the flowchart lists out greenhouse gases and global warming separately and shows feedbacks going back into those two blocks separately. One other way to think of all this is to consider updating the flowchart to be better and reflect the IPCC data. For instance:

1. The overall flowchart color is wrong; it should be blue since you are including planck effect as a negative feedback. Blue is true both for greenhouse gases and global warming.
2. The list of greenhouse gases in the greenhouse gases box should probably be cut. That would allow the top two blocks to be the same width and font, lowering the visual noise and overall word count.
3. It's weird having positive feedbacks on the left and negative feedbacks on the right, they should flip.
4. Since gases are spelled out next to the feedback arrows pointing to "Greenhouse gases", it seems that radiative effects feeding back into "Global warming" should also be spelled out. Planck causes "energy radiated into space", and albedo change causes "more energy absorbed". That would also allow all feedback descriptions to be 2 lines tall instead of having a few that are 3 lines tall.
5. IPCC data could possibly be visually represented in each feedback you list. I don't have a clear idea for this, but you already have a center line that is perfect for a bar chart, and your feedback descriptions could become labels.
6. As per the IPCC, it seems like methane release should be replaced with "carbon response to climate" which would aggregate the last two IPCC bars. That's less intuitive to communicate, but methane release from permafrost is really a rounding error effect.
7. As per the IPCC, carbon response to increased CO2 should probably be split into land and ocean, not plants and ocean (since much plant life in the ocean is a major sink).
8. So that font sizes for feedbacks can be larger maybe look to extend the image height and put positive and negative feedbacks in separate row areas instead of side by side.

Efbrazil (talk) 21:45, 24 May 2024 (UTC)

July 2022+ feedbacks diagram

20240522 Climate change feedbacks.svg (ver1 May 22, ver2 May 29)

1. I don't grok the color criticism. Red tends to warm and blue tends to cool. What is the meaning of "blue is true"?
2. There's value in listing the GHGs, esp. when it isn't clear that the gas legends now in the feedback paths are in fact GHGs, and N2O would be missing altogether. Also, widening the GHG block as suggested, would make it impossible to fit the GHG names in the feedback paths.
3. ? I wasn't aware of left-right standards for feedback loops. ~All feedback diagrams I've ever seen have blocks oriented horizontally with feedbacks returning from right to left—which we don't do here because of text readability. Do you remember {} that was superseded?
4. Now, the language is simple English sentences for laymen. To add verbal text to feedback paths actually makes readers figure those things out instead of just reading English sentences as now. And 2 vs 3 lines is 100% stylistic.
5. ? Combining a flowchart and a bar chart? I have no clue what that complication would even look like, or how laymen would view it.
6. "Carbon response to climate" is impenetrably techy language. The flowchart (if that's what you're still talking about) presents readily understood concepts. Separately, "Land/Ocean carbon response to climate" are already in the bar chart that's suitable lower in article; combining two bars would constitute iffy SYNthetic calculations.
7. Is it even accurate that land^{(="dirt" to the laymen)} absorbs CO2? "Land"="dirt" actually excludes plants. And plants-in-the-ocean don't become sinks until after the ocean first absorbs CO2, so "Oceans remove CO2..." is more inclusive.
8. Putting + and - feedbacks vertically above each other would alter the + vs - symmetry about the descending centerline, and would increase the flowchart's vertical space in articles by ~33%, in addition to the increased height resulting from using larger fonts.

—RCraig09 (talk) 04:33, 25 May 2024 (UTC)

1. Blue is true as net global warming feedback and net greenhouse gas feedback are both negative according to the IPCC.
2. I would not widen the GHG block, I'd collapse the Global warming block to match the GHG block.
3. Left / right would be if you want to add data to the items, as per the Climate feedbacks chart
4. Yes, keep simple english
5. OK, I'll take a crack at it. Have been busy the last few days, hopefully can get to it this week.
6. Agreed, that's a tension to figure out. I don't have a good resolution in mind yet.
7. Land absorbs CO₂ in the form of mineral weathering. Good point about plants absorbing CO2 from the ocean. Regardless, the point is to follow the IPCC breakdown rather than making something up.
8. All true, but it's what you're doing in the climate feedbacks graphic up above. I'll need to play around graphically to figure out what makes sense.

Efbrazil (talk) 18:51, 28 May 2024 (UTC)

I plan to expand the bar chart vertically per the last paragraph of my 20:20 22 May #8 in my 04:33 post. Re 5 and 8, it sounds like you're planning to combine a flowchart and bar chart, which would blow a lot of minds; you may want to do a hand drawing before investing serious time. —RCraig09 (talk) 20:22, 28 May 2024 (UTC)

Version 2 of bar chart is now uploaded (29 May), with a vertically oriented aspect ratio to make it easier to read legend text. But the legends are still too techy for a lead image. I've boldly insert the chart into the /* Physical feedbacks */ section, hoping cognoscenti here will refine the caption. —RCraig09 (talk) 22:48, 29 May 2024 (UTC)

Yeah, a lot of the legends seem unchanged from the AR6 graphic this was based on. I would prefer to change the following:

• "Thermal radiation" (does not tell much of anything on its own) -> "Heat/Infrared loss to space" (similar to what is already on the flowchart"
• "Clouds" -> "Cloud cover change" (I don't want anyone to assume that clouds themselves have a heating effect, and while longer, this wording makes it clear)
• "Land carbon response to CO₂" -> I think to a lot of people it's just going to look like "Carbon responds to carbon? What?" So, "Land biosphere response CO₂" would be preferable, IMO.
• "Ocean carbon response to CO₂" -> Just ditch the word carbon, IMO.
• "* "Land/ocean carbon response to climate" -> Change "climate" for "warming" in both. And as above, replace "carbon" with "biosphere" for land, and take it out entirely from the ocean.

Another thing: shouldn't the flowchart - - have the arrowheads going in the other direction on the blue side? Carbon dioxide is going from the pool of greenhouse gases and into plants and the ocean. Similarly, negative feedbacks effectively take warming away, so the arrowhead going into the Planck rate box would make sense. InformationToKnowledge (talk) 18:59, 30 May 2024 (UTC)

I'll wait for Efbrazil and others to opine re changing the bar chart's legends from in the IPCC reference. Separately: the arrows in the flowchart are in the correct direction since they emphasize feedback paths.

PS – I'm planning to switch left and right in the flowchart so red (positive feedbacks) are on the right per Efbrazil's suggestion to comport the flowchart with the bar chart. —04:00, 31 May 2024 (UTC)  Done Version 12 uploaded. —RCraig09 (talk) 06:12, 31 May 2024 (UTC)

That's better, but I now notice that the entire left half should be shaded blue then. Right now, blue shading cuts off right below the "global warming" box, so the red colour occupies more space, visually implying that the positive feedbacks are more dominant. As we all know now, it should be the opposite, if anything. So, either the entire left half is blue, or a third colour is used to shade the top part of the background on both sides.

I have also spotted further inaccuracies with the text:

Snow cover loss and ice shelf melt - A reminder of what an ice shelf actually is. On a global scale, the surface area of all ice shelves is absolutely tiny, and I never saw any paper bother to single them out for any radiative effect. Presumably you meant to write ice sheet, but that is also incorrect, since practically all the melting to date had occurred on their margins - Greenland's surface did get darker, but not enough for a meaningful global impact. Virtually all the albedo feedback to date is from the sea ice loss followed by snow cover. As a bonus, writing Snow cover and sea ice decline should allow you to reduce it to two lines, not three. (Planck box staying at three will visually highlight its importance.)

Thawing permafrost releases methane into the air - Permafrost emits a lot more CO₂ than methane - by an order of magnitude or thereabouts. It is only the difference in GWP which (probably) makes warming from methane larger - and even then, it's a 70%/30% ratio at most. I am guessing you decided to omit CO₂ emissions from positive feedbacks because they are far outweighed by absorption? (In which case, this could still warrant a small * note at the bottom.)

Even so, there is the fact that tropical wetlands almost certainly release far more methane altogether, and it is only the fact that they are better modelled already (and that you can't show exploded craters and bubbling ponds with them) which causes permafrost to receive more attention. Perhaps the better wording would be Thawing permafrost and warming wetlands release methane? (Warming permafrost and wetlands release methane if you can't fit it into two lines otherwise.) I think we can trust our readers to fill in the blanks and not have to specify "in the air" on this one.

Lastly, if we are ranking feedbacks in the order of importance, then water vapor should be first, and cloud feedback should be next, with ice-albedo following and permafrost, etc. last. IMO, a succint way to describe it would be Clouds become thinner and reflect less sunlight. To balance it, the negative feedback side could describe lapse rate as more heat is lost at higher altitudes. This shouldn't add too much space to the graphic, and will make it far more accurate. InformationToKnowledge (talk) 11:28, 31 May 2024 (UTC)

July 2022+ feedbacks diagram

20240522 Climate change feedbacks.svg (ver1 May 22, ver2 May 29)

Alrighty then! Some excellent suggestions have been implemented in flowchart Version 13 (31 May 2024). The only substantive exception is that the flowchart shows feedback concepts rather than the more complex ranking. 20:24, 31 May 2024 (UTC)     + Important observations about ranking can be included in textual captions. —RCraig09 (talk) 20:26, 31 May 2024 (UTC)

If you have further suggestions, it's best to provide a concise suggestion, almost like a formal edit request. Reasoning can be appended. —RCraig09 (talk) 01:54, 1 June 2024 (UTC)

Fair enough. This version is already a significant improvement as well!

My main suggestion would be to at least experiment with a four-point list version. That is, add lapse rate to the left and clouds on the right. (Suggested wording in the last paragraph of my previous version.) You can upload that as a separate file so that the 3-point and 4-point versions can be compared side by side.

Another comment would be to add soil to the wetlands and permafrost somehow. If that forces the box to expand to three lines, perhaps ice-albedo can be simplified to two? InformationToKnowledge (talk) 17:31, 1 June 2024 (UTC)

It seems that "lapse rate" is a techy detail of how a feedback occurs rather than constituting a feedback on par with the other readily understandable feedbacks shown. And "clouds" seem to be a part of water vapor that's already on the right. Shortening the present language to "albedo" just to save space is a step away from the common language our readers need. Adding "soil" to wetlands/thermafrost as a positive feedback is at odds with soil that has just been added to "plants and soil" on the negative feedback side. Generally speaking, this intro graphic focuses on concepts rather than rankings and exhaustive completeness, and I'm disinclined to spend hours "experimenting" (it's a text-edit SVG file, not a bloated file generated by a glossy commercial editor). —RCraig09 (talk) 20:23, 1 June 2024 (UTC)

Efbrazil 6 June 2024

2022 version

To the right is a preliminary cut at merging the graphics. I didn't do the work to get it looking ready to go live, but figured this is good starting point to gather feedback. A few notes on the decisions I made in putting it together:

1. Fonts are legible on smartphone and will approximate look of wikipedia after I touch them up
2. Feedback from more CO₂ in air does not require global warming, that's separate and so is at top
3. Feedback bars specify where lost CO2 and heat is going, which I think helps with understanding
4. Positive feedbacks are sorted in order of magnitude
5. Wording attempts to avoid jargon and split the difference in complexity between the IPCC chart and the feedback chart Craig made
6. Size of bars and contents are based on the IPCC source, although it is simplified. While I understand people may complain about the simplifications, I think it is better to base an intro graphic like this on real data.

Efbrazil (talk) 16:36, 6 June 2024 (UTC)

Bravo! This concept deserves the Palme d'Or for graphics. The important change I'd make is to group the blue boxes below the Global Warming box, so the feedbacks are, well, fed back as in the 2022 version.^{Re #2: I thought CO2 increased as a result of GW, through wildfires etc. -- not sure that plants absorb more CO2 just because there's more of it.} Also, that new grouping would allow light blue and light red "background rectangles" to visually distinguish opposing factors appropriately. It's initially paradoxical to cite plants at both the top and bottom, both negative and positive; I don't know if "CC affects plants" is dominant, often-cited or even accurate overall. I'd use the 2022 flowcharts's factors and feedbacks as a starting point, though choice of factors is endless arguable. —RCraig09 (talk) 22:43, 6 June 2024 (UTC)

Thanks Craig! Very glad you like it!

Regarding CO2 feedbacks, there are really 2. There's the CO2 response to more CO2 in the air, which is a strongly negative feedback and the first feedback listed above. It's what the IPCC carbon feedback chart calls "Land response to more CO2" and "Ocean response to more CO2" (which I aggregated). That's not part of global warming, it's simply an artifact of more CO2 in the air (the planet has consistently absorbed a steady percentage of annual emissions, instead of a fixed amount of emissions, which has been very helpful in limiting climate change). On the flip side, the positive feedback is that global warming is reducing the ability of the planet to absorb CO2, which is the last feedback in the version of the chart I created, and that's the one that includes wildfires, drought, and so on. Make sense?

I'm not sure what you mean by "group the blue boxes". Did you mean moving the "More CO2 absorbed" label down? I want that directly beneath emissions and above global warming, for the reasoning above.

These are the changes I made:

1. Colors of the arrow lines now match the feedback direction (red or blue). I figure that along with the side bar descriptors with a color along with the bar chart colors is hopefully enough. I can't add a light blue / light red background like in your graphic because the grouping is no longer a tidy left side vs right side.
2. I updated the last label to be clear about biomass loss, which is the main impact as I understand things to CO2 levels from climate change. If you think that's a bit too far from source let me know, I could scale back to something more like the IPCC label.

Let me know what you think, and thanks again for the encouragement! Efbrazil (talk) 23:45, 7 June 2024 (UTC)

Yep, by "group the blue boxes" I just meant to have a light-blue background rectangle like the 2022 flowchart, but if you're certain of the relative strengths of processes and connections of pathways I won't pursue a formal presentation issue at the expense of a substantive scientific conclusion. Bottomline: I'm OK with the combination bar chart / flowchart, though I caution against WP:SYNTH and would await expert comment. (Aside: I think some of the terms are unfriendly, like "thermal radiation" and "biomass". Some of the issue can be resolved with careful captioning, but there's no guarantee other users will adopt the same careful captioning when they use the graphic.) Separately, though there seems to be some progress (questionable) at Wikimedia re SVG text rendering issues (see https://phabricator.wikimedia.org/T97233), I think it's still safer to use "CO2" in regular text rather than using subscripts/superscripts. —RCraig09 (talk) 02:10, 8 June 2024 (UTC)

Good point on thermal radiation. It's the term we use elsewhere, but it's always well explained when we do. I think "more heat radiated" is fine as an alternative. Including that tweak and making another pass on the text resulted in these changes:

1. Thermal radiation from a warmer planet --> More heat radiated from a warmer planet
2. More water vapor in warmer air absorbs thermal radiation --> Water vapor (a greenhouse gas) increases as air warms
3. Changes to cloud cover traps more thermal radiation --> Changes to cloud cover traps more radiated heat
4. Biomass loss due to impacts like wildfires releases CO2 --> Lost plant life and warmer oceans limit CO2 absorption

I also did the post processing necessary to go live, including font fixes and joining all phrases for easy localization. I think this is far enough along that I went ahead and replaced the lead graphic with this. If anyone has further thoughts they can chime in here hopefully. Efbrazil (talk) 17:53, 8 June 2024 (UTC)

Excellent job on the techy-->English translation. Tiny note: "Changes...traps" is a singular/plural mismatch. I don't see any problems with text spacing. For future reference: note there is a https://commons.wikimedia.org/wiki/File:Test.svg to experiment and test; it goes away after a while. —RCraig09 (talk) 18:06, 8 June 2024 (UTC)

I agree that the graphic is looking great. Well done! With this improvement, I also decided that this page appears to have gotten fairly close to its potential, and nominated it for GA. Let's see how it's going to go. InformationToKnowledge (talk) 18:33, 8 June 2024 (UTC)

Thanks all! Traps --> Trap in the graphic. I'll use that test graphic location in the future. As you can see in the image history wikimedia was messing with me by not honoring white space at the beginning and end of tspans and text tags, so I ended up using dx="10" on tspans to add relative spacing to the text on the left. Efbrazil (talk) 18:58, 9 June 2024 (UTC)

Addressing the issue of what is a climate change feedback in the definition section

I believe we need to say what qualifies as a climate change feedback in the definition section. After all, we just burned through a lot of time discussing that exact issue up above on this talk page, and it seems critical to define the scope of climate change feedbacks in an article on climate change feedbacks. Here is what I added to the beginning of the definition section, which is my best attempt to condense the discussion above:

Climate change feedbacks are only sometimes defined to include the Planck response, which defines how much more thermal radiation warmer objects emit. The Planck response is included when calculating the net feedback parameter that determines climate sensitivity. However, it can also be excluded in the context of climate science as it is considered to be an intrinsic aspect of warming rather than a response to it. To be precise it is best to qualify climate change feedbacks as net feedbacks or to speak of net feedback categories, which are the Planck response, radiative feedbacks, and carbon cycle feedbacks.

InformationToKnowledge reverted it with this comment: Not an improvement. I doubt this will make sense to readers who have not read the talk page, and it doesn't make sense to feature this early in the article. Either place a shorter version in the Planck section itself, or omit it entirely.

I disagree strongly on the placement issue. We are in the definition section and this is critical for defining the topic of the article. I can see the argument that this might be hard for someone new to understand at first, but I think it is best to be precise here at the expense of accessibility. Perhaps someone can come up with better wording. Anyone else care to comment, particularly RCraig09 and Femke? Efbrazil (talk) 18:08, 14 June 2024 (UTC)

References

I agree that the article should mention how the Planck response can be included or excluded, and the first three sentences capture this succinctly (and, to seriously readers, understandably). The first three sentences aren't overly techy for this technical subject. However, my forehead scrunched a bit when I saw the words "it is best to..." in an encyclopedia, and the fourth and final sentence is not clear to me, at least without wikilinks for the three listed categories. I'm undecided whether the article should briefly explain the second and third listed categories at that specific point, either in text or in an informational footnote. —RCraig09 (talk) 20:43, 14 June 2024 (UTC)

Yeah, good point. Here is a rewording that eliminates that last, awkward bit:

Climate change feedbacks are only sometimes defined to include the Planck response, which specifies how much more thermal radiation an object emits as it gets warmer. In climate science the Planck response can be treated as an intrinsic part of warming that is separate from radiative feedbacks and carbon cycle feedbacks. However, the Planck response is included when calculating the net feedback parameter that determines climate sensitivity.

Does that work for you InformationToKnowledge? Efbrazil (talk) 21:41, 14 June 2024 (UTC)

on the 21:41 post, but suggesting: add wikilinks to radiative feedbacks and carbon cycle and omit unnecessary "the net feedback parameter that determines". —RCraig09 (talk) 17:31, 15 June 2024 (UTC)

That all works for me / done! Efbrazil (talk) 19:53, 15 June 2024 (UTC)

Sentence in lead about physical feedbacks is difficult to read

I find this sentence too difficult to read. It contains an enumeration of 4 things. Why not split it into two? I mean this sentence: Physical feedbacks include increased water vapor from evaporation, altered cloud distribution, decreased surface reflectivity as snow and ice cover diminishes, and an amplification of the rate at which atmospheric temperature falls with rising altitude.. My proposal was two sentences each with two feedbacks: Physical feedbacks include increased water vapor from evaporation as well as altered cloud distribution. Another two physical feedbacks are decreased surface reflectivity (albedo) as snow and ice cover diminishes, and an amplification of the rate at which atmospheric temperature falls with rising altitude.. I think this is a valid way of splitting a long sentence in two. Efbrazil reverted this with the explanation "To split a sentence you must have separate subjects for each sentence.". I don't think this is true. Who says so? I've seen long sentences with long enumerations split in similar ways before. - Can you think of other ways of making this sentence easier to read? EMsmile (talk) 21:58, 17 June 2024 (UTC)

Alternative proposal (first sentence has 3 items, second sentence just one; they are linked with "additionally"): Physical feedbacks include increased water vapor from evaporation, altered cloud distribution, and decreased surface reflectivity as snow and ice cover diminish. Additionally, there is an amplification of the rate at which atmospheric temperature falls with rising altitude. EMsmile (talk) 21:58, 17 June 2024 (UTC)

I agree with Efbrazil: a well-ordered list of four items separated by commas reads more smoothly. The 2+2 and 3+1 alternatives read choppy, break up the flow, and are another attempt to elevate formal rules against how substantive content is encountered as a well-ordered list of comparable-importance items. —RCraig09 (talk) 22:31, 17 June 2024 (UTC)

I think you are identifying a valid issue, but fixes require understanding the content and making sense of it so that you can help the reader digest the content. Breaking up a list into 2 sentences and then joining them with something like "additionally" or "another" makes the problem worse. The list remains just as long, and now you are forcing the reader to digest extra words and breaks that are meaningless.

Let's consider how to digest the content for the reader. One way to break things down is that we are covering water vapor through three of the items, so maybe they could be combined. We also aren't helping the user understand why lapse rate matters, but instead are just throwing in the definition of lapse rate and saying that's a feedback. So we could split the content around water vapor and be less pedantic about lapse rate. That would leave us with something like this:

Physical feedbacks include decreased surface reflectivity as snow and ice cover diminish plus increases to atmospheric water vapor. Water vapor is a powerful greenhouse gas and combines with feedback changes in how clouds and temperatures vary by altitude. Efbrazil (talk) 15:35, 18 June 2024 (UTC)

I agree that conceptual understanding should govern over empty rules that lack context. However, the 15:35 proposed language structure perplexes me: "diminish plus" seems like a run-on connective phrase, and "feedback changes" is unclear whether changes is a noun or a verb. Even after reading several times, I'm unsure what either sentence means. The particular language would have to be worked on in order to improve over a simple-though-long 4-item list. —RCraig09 (talk) 16:23, 18 June 2024 (UTC)

Good points Craig. Below is a cut that tries to address those issues. Note that our current text is not only tough to digest it's also kind of incorrect, as water vapor increases not just from increased evaporation, but also because warmer air holds more moisture. Also, the lapse rate changes are more complicated than simply saying that the temperature gradient increases, as changes vary by latitude, and the same applies to clouds. So I'm aiming for better accuracy here in addition to accessibility:

Physical feedbacks include decreased surface reflectivity (from diminished snow and ice cover) and increased water vapor in the atmosphere. Water vapor is not only a powerful greenhouse gas, it is also influences feedbacks in the atmospheric distribution of clouds and temperatures. Efbrazil (talk) 23:22, 18 June 2024 (UTC)

Now that hits the spot for clarity. I'd formally touch up the final sentence to be Water vapor is not only a powerful greenhouse gas in its own right, but it is also influences feedbacks in the atmospheric distribution of clouds and temperatures in the atmosphere. The final phrase invites further inquiry, but as an intro paragraph it seems good. —RCraig09 (talk) 02:42, 19 June 2024 (UTC)

Thanks to both of you for working on this! It's all pretty complex and not easy to explain to laypersons. My attempt at making it easier to read was way too simplistic, I see that more clearly now. I like the new proposal of wording, it makes it much clearer. Would you say it's OK to leave out the fourth physical feedback then which was "and an amplification of the rate at which atmospheric temperature falls with rising altitude" (this one might require an additional sentence to explain it better?)? EMsmile (talk) 08:48, 19 June 2024 (UTC)

Thanks for the encouragement! Lapse rate is covered by mentioning temperature variation in the atmosphere. The issue is too complicated to cover in detail in the lead. There is a wikilink to the topic and it is covered in the article.

I made the edit taking some of Craig's changes. I'm not crazy about the phrase "in its own right" as it reads to me like a personification, so I left that change out. Rights belong to people and animals. Also, the clouds wikilink now goes to the clouds feedback instead of just clouds. Efbrazil (talk) 15:03, 20 June 2024 (UTC)