Talk:Climate sensitivity

Did you know
I'm quite confident the article will pass the GA nomination (or in the worst case, the next one), so will start preparing for a WP:Did you know.
 * 1) ... that climate scientist can estimate climate sensitivity to carbon dioxide by studying how much climate changed in Earth's past.

Please leave a comment if you'd like a different fact or a rewording.

Potential sources

 * List of related papers
 * Informal discussion by expert

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.

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)

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)

Background section?
I am always a bit wary when I see a section in any of our climate change articles that is called "Background". I feel that a "background" section could become too big - where to start and where to stop - and overlap or be repetitive with other articles. In this case here, is "background" really the ideal title? Perhaps rather call it "Fundamentals", "Theoretical basis", "Rationale" or something like that? EMsmile (talk) 20:40, 20 September 2023 (UTC)


 * Update: I've changed it now to "Fundamentals". EMsmile (talk) 10:30, 2 April 2024 (UTC)

Readability issues with the lead
I came here to make some quick improvements to the readability of the lead. However, as the article is a GA article, I hesitate to jump straight in. Is anyone who was involved in the earlier GA review still here and open to readability improvements? Currently the entire third paragraph and almost the entire first paragraph lights up in dark red with the readability tool. Also, I find the caption for the image in the lead is rather long and complicated. Pinging User:Jonesey95 and User:Femke. - I am happy to give it a go but don't want to step on anyone's toes (and might also not get it perfectly right on the first go as it's not my area of expertise). EMsmile (talk) 12:51, 22 March 2024 (UTC)
 * You're not stepping on my toes. Many of the changes since my copy edits in 2020 are clear improvements; some of them make me wince a bit that I missed them. – Jonesey95 (talk) 13:28, 22 March 2024 (UTC)
 * Feel free to step in here. I've rephrased the 3rd paragraph. The sentences are still long, but they should be much clearer now. If in doubt about whether your suggestions change the meaning, feel free to ping me again. —Femke 🐦 (talk) 16:26, 22 March 2024 (UTC)
 * OK, thank you to both of you for your quick replies. I'll do some cautious editing for readability tomorrow or otherwise when I get back from holidays in a week from now. Thanks for working on the 3rd paragraph, too. The readability tool now shows a light red instead of a dark red for the first sentence of the 3rd para. So that's progress. Of course this readability tool is not the "be all and end all" but overall I find it very useful. It "punishes" multi-syllable words though, so with the 5-syllable word "sensitivity" it won't be easy to get the reading ease score up. EMsmile (talk) 21:54, 22 March 2024 (UTC)
 * I've done a bit of work on the reading ease and the structure of this article (see details in my edit summaries). I hope everything is correct. I'll add some questions below in separate sections. EMsmile (talk) 10:30, 2 April 2024 (UTC)
 * However, the last sentence of the lead still has a low readability score but I don't know how to improve on that: Estimates of climate sensitivity are calculated by several methods: by looking directly at temperature and greenhouse gas concentrations since the Industrial Revolution (so around 1750 onwards), by using indirect measurements from the Earth's distant past, and by using climate models to simulate the climate. EMsmile (talk) 10:38, 2 April 2024 (UTC)
 * That shows that these readability tools should not be blindly believed. The sentence is easy to parse. —Femke 🐦 (talk) 16:11, 2 April 2024 (UTC)
 * It's fairly easy to understand, yes, but someone trained in science communication could probably improve it further. Anyhow, happy to live with it like this. - I find the tool a wonderful helper just to point out those sentences that are (potentially) difficult to understand. EMsmile (talk) 08:17, 4 April 2024 (UTC)

Is "doubling" integral to the definition?
I see the wording of "doubling" mentioned a few times, e.g. in the first sentence of the lead, as if it's part of the definition. However, the IPCC definition does not include "doubling". Are there different trains of thought here? Do we need to emphasise the "doubling" aspect by having it in the first sentence of the lead? If so, this should be clarified in the "definition" section. EMsmile (talk) 10:32, 2 April 2024 (UTC)


 * Yes, it is. Look at any definition of any type of climate sensitivity and you will see a doubling as part of it. —Femke 🐦 (talk) 16:11, 2 April 2024 (UTC)
 * The IPCC definition does not include "doubling" though? And why should it. Doubling is just an arbitrary figure. Also, why did you remove the whole section on definition that I had added (here)? It is not duplicated content. I think a section on "definition" is important and should be in a place where the reader can easily access it. At the moment it is hidden in other sections. It's mentioned in the lead but not in the main text. EMsmile (talk) 09:32, 3 April 2024 (UTC)
 * Here is the content that you removed (I would agree to removing the second definition if you think it's not good but the IPCC definition is useful, in my opinion):
 * === Definition ===
 * The IPCC Sixth Assessment Report defines climate sensitivity as follows: "The change in the surface temperature in response to a change in the atmospheric carbon dioxide (CO2) concentration or other radiative forcing." It further distinguishes between (see below for more details):
 * Earth system sensitivity
 * Effective equilibrium climate sensitivity
 * Equilibrium climate sensitivity (ECS)
 * Transient climate response (TCR)
 * Transient climate response to cumulative emissions (TCRE)
 * Another definition of climate sensitivity is as follows: climate sensitivity is the average change in global mean surface temperature in response to a radiative forcing, which drives a difference between Earth's incoming and outgoing energy.
 * EMsmile (talk) 09:32, 3 April 2024 (UTC)
 * EMsmile (talk) 09:32, 3 April 2024 (UTC)
 * All the types of climate sensitivities by the IPCC use the doubling, as does the Met Office definition, the NASA definition, the Carbonbrief explainer.. that's simply what this is. —Femke 🐦 (talk) 16:48, 3 April 2024 (UTC)
 * Sorry if I am slow on this but so the IPCC def of sensitivity does not include doubling ("The change in the surface temperature in response to a change in the atmospheric carbon dioxide (CO2) concentration or other radiative forcing.") but the def of the individual types of sensitivity does include doubling? EMsmile (talk) 22:04, 3 April 2024 (UTC)

Question about main headings
There are two main level headings that for me don't make sense as main level headings: "Sensitivity to nature of forcing" and "State dependence". Could we move them to be within either "Fundamentals" or "Measures"? I don't understand how they fit into this article otherwise. The other main level headings are quite clear. We have now:
 * Fundamentals
 * Contributors
 * Measures
 * Estimates
 * Methods of estimation EMsmile (talk) 10:35, 2 April 2024 (UTC)


 * Well, neither are a type of climate sensitivity (which is renamed into measures), and neither are fundamental concepts to climate sensitivity. Not that fundamentals is a good section heading (it's too vague). I've renamed contributors, as that word usually refers to humans who contribute, not to things. —Femke 🐦 (talk) 16:28, 2 April 2024 (UTC)
 * It's still not clear to me what those two sections are doing there as main level headings. Would prefer more generic main level headings, like the other ones are. The current TOC structure is now (in bold the two that don't fit well in my opinion):

As a lay person it is fairly intuitive to know what is under "estimates" or "methods". But what is under "state dependence"? Unclear. EMsmile (talk) 09:35, 3 April 2024 (UTC)
 * Fundamentals
 * Factors that determine sensitivity
 * Measures (should this rather be "types"?)
 * Sensitivity to nature of forcing
 *  State dependence
 * Estimates
 * Methods of estimation


 * Does "dependence on Climate state" help? Sensitivity to nature of forcing is clear to me. I don't expect a pure lay audience to this article, given it's a theoretical concept within climate science. —Femke 🐦 (talk) 16:51, 3 April 2024 (UTC)
 * True but the concept of climate sensitivity is up and coming. So if at all possible we might as well try to make it lay person friendly by ensuring that at least the main level headings are understandable. I am a lay person on this topic and I struggle with these two main section headings (the others are fine).
 * I find it also odd that these two sections are actually very short compared to the other main level sections - this can sometimes indicate that something is not quite right with the structure.
 * "Sensitivity to nature of forcing" is not clear to me (and by the way, that section consists of just one long paragraph; should be broken in two somewhere).
 * Can you maybe think of a generic section heading that both these sections could fall under? This might help with clarity. Perhaps "Factors that determine sensitivity", or "Factors that sensitivity depends on", or "Boundary conditions"? Again, my apologies for not grasping this better. EMsmile (talk) 22:18, 3 April 2024 (UTC)

Factors that determine sensitivity: hidden comment
At the end of the section that is now called "factors that determine sensitivity" there is a hidden comment as follows:

"Do we need this section? If so, why? It seems to be out of place with the rest of the article >> Although the term "climate sensitivity" is usually used for the sensitivity to radiative forcing caused by rising atmospheric, it is a general property of the climate system. Other things can cause a radiative imbalance. Climate sensitivity is the change in surface air temperature per unit change in radiative forcing, and the climate sensitivity parameter is therefore expressed in units of °C/(W/m2). The measure is approximately the same, whatever the reason for the radiative forcing (such as from greenhouse gases or solar variation). When climate sensitivity is expressed as the temperature change for a level of atmospheric double the pre-industrial level, its units are degrees Celsius (°C)."

I don't know when it was added and by whom. Is there something we ought to do to address this? EMsmile (talk) 09:41, 3 April 2024 (UTC) EMsmile (talk) 09:41, 3 April 2024 (UTC)

Mentioning IPCC explicitly or not?
Hi Femke, I used to mention IPCC explicitly quite often but was told by you not to (see here discussion from 2 years ago). This made sence to me and ever since then, I have mentioned IPCC only sparingly (like in a section on definition of a term). But now my edit to remove the IPCC mention was reverted by you here. With the justification "restore IPCC in-text. Scientists say is much weaker than a consensus statement".

Does that mean you no longer avoid the explicit IPCC mentions? I think lay persons have no clue what IPCC is so it might be better to use different wording. Like "The scientific consensus in 2022 is xxx". (rather than "scientists say" and rather than "The IPCC literature assessment estimates" or "The ocean heat uptake estimated by the IPCC AR5 as" or "The IPCC Sixth Assessment Report (AR6) stated that there is high confidence that"). EMsmile (talk) 09:49, 3 April 2024 (UTC)


 * Don't cite the IPCC inline when you're dealing with facts (ice is melting, temperature has risen 1.2 degrees, i.e. most of the time). Do cite them when they make an assessment. Avoid "scientists say", as it's vague. —Femke 🐦 (talk) 16:43, 3 April 2024 (UTC)
 * How about “scientists agree” or “scientists generally agree” or “most scientists agree” in some places where we would like a simpler word than “consensus” Chidgk1 (talk) 18:11, 3 April 2024 (UTC)
 * That's WP:weaselly. And probably also not quite accurate, as each scientist will have their own best estimate of ECS. —Femke 🐦 (talk) 18:21, 3 April 2024 (UTC)
 * I am not too sure what the difference between "facts" and "assessments" is here. The amount of ice melting is an assessment but also a fact (or estimated fact), isn't it? When does an assessment become a "fact".
 * Also, do you agree that these sentences are not overly lay-person friendly?: "The IPCC literature assessment estimates" or "The ocean heat uptake estimated by the IPCC AR5 as" or "The IPCC Sixth Assessment Report (AR6) stated that there is high confidence that". The topic of "climate sensitivity" should be up and coming so I think we would do a better service to our readers if we make it layperson friendly.
 * So instead of "The IPCC literature assessment estimates that the TCR likely lies between xxx", how about "Current estimates found that the TCR likely lies between xxx".
 * And instead of "The IPCC Sixth Assessment Report (AR6) stated that there is high confidence that ECS is within the range of...", how about: "In 2022 the ECS was found to be within the range of" (in my opinion, these are facts; it's a fact that the estimates are xxx). An estimate (or "best estimate") is still a fact. EMsmile (talk) 22:01, 3 April 2024 (UTC)

The study about 7-14 degree temperature rise if CO2 level is doubled
I have published in the section "Using data from Earth's past" the next text:

"In 2024, a group of scientists used sediments from the Pacific Ocean for checking the climate sensitivity to CO2 concentration, and found that a doubling of the amount of CO2 in the atmosphere could cause an increase in temperature of 7-14 degrees."

This is the link.

https://www.sciencedaily.com/releases/2024/06/240624125500.htm

It was deleted as "single study of a small area".

https://en.wikipedia.org/w/index.php?title=Climate_sensitivity&oldid=prev&diff=1233134102

I do not think it is correct. I am not sure that the others studies in this section are bigger. Also I think that considering the importance of the issue even if you think that it is still express a minority view in the scientific community, you can not ingnore it. You can write like "These findings contrast sharply with the 2.3 to 4.5 degrees predicted by the Intergovernmental Panel on Climate Change (IPCC)" like did Earth.com when it wrote about it:

https://www.earth.com/news/atmospheric-co2-could-push-temperatures-much-higher-than-expected/

But I think you can not ignore it.

Especially as many scientists are consistently plaign that the warming is going faster than their models. This can explain it. If for example after the appearence of this study other scientists have said " that is false we do not agree" than it will be other thing. But I do not see an overall negative reaction to this study.

Except this study used more exact methode than previouse studies at least this is what is written in the earth.com:

" Invaluable resource for the study

The researchers used a 45-year-old drill core from the Pacific Ocean floor to gather their data. The core preserved organic matter due to the lack of oxygen, making it an invaluable source for studying historical climate conditions. “I realized that this core is very attractive for researchers, because the ocean floor at that spot has had oxygen-free conditions for many millions of years,” said senior author Jaap Sinninghe Damsté, a scientist at NIOZ and professor of organic geochemistry at Utrecht. The experts were able to construct a unique time series of CO2 levels over the past 15 million years from a single location, a feat that had not been achieved before.

They used the TEX86 method to determine past seawater temperatures, a technique developed at NIOZ 20 years ago that analyzes the chemical composition of archaea membrane lipids. Additionally, they developed a new method to estimate past atmospheric CO2 concentrations using the chemical signatures of chlorophyll and cholesterol from algae. This approach is the first to use cholesterol for quantitative CO2 estimates and to apply chlorophyll data to this time period. "

So I think it should be mentioned. If you want, you can add that this is not what the IPCC think, that it is a small study and so on. Alexander Sauda/אלכסנדר סעודה (talk) 12:53, 8 July 2024 (UTC)


 * The more extreme a statement is, the higher quality the source must be. This is quite an extreme statement, so a single primary study is not suited to this. WP:SCIRS gives more information. So much is published on this topic that we don't need to rely on primary sources really. They're are a few old primary sources in the article now that can be deleted instead. —Femke 🐦 (talk) 16:19, 8 July 2024 (UTC)