Talk:Carbon dioxide in Earth's atmosphere/Archive 2

Image used in the lead
I have just swapped two images within the article so that we now have an image in the lead that shows changes in CO2 concentrations over time, whereas the previous one just showed data for 2011 and was actually taking up a large amount of space for not showing very much. I think it's important to see if we agree on this aspect: do we think that this article should be mainly about changes to CO2 concentration in the atmosphere over time (long term and short term), or do we see it as an article that should be quite separate from anything to do with climate change and should just talk about the fundamentals of why CO2 is in the atmosphere in the first place and things like that. Personally, I think we might have many readers coming to this article wanting to know about why CO2 concentrations are going up and what it means. So we should give them that information. If not then we should point them to another main article if that is what we prefer. This is related to my discussion points about the structure above. EMsmile (talk) 15:01, 26 November 2021 (UTC)
 * Image look fine to me. Re text can't this article do both? I mean text from sections like "Drivers of ancient-Earth CO2 concentration" could be fitted into your new structure I guess? Chidgk1 (talk) 08:29, 29 November 2021 (UTC)
 * Hi Chidgk1: Coming back to this conversation from a year ago. I've now chosen the image on the right for the lead (Mauna Loa CO2 monthly mean concentration.svg). It's a clear image but it does only show the more recent data - which I think is justifiable, and I've added in the caption the explanation about the situation in the geologic past. I just think if we chose an image that shows the CO2 concentrations going back millions of years, this will obscure the point of the recent increase and the human influence on that. I've also changed the ordering of the article accordingly. I'll also write about that in the other section of the talk page just now. EMsmile (talk) 11:02, 9 December 2022 (UTC)
 * (the previously used image for the lead is the second one on the right (Phanerozoic Carbon Dioxide.png) which I find too complex for the lead image and not showing clearly our current problem of rapid CO2 rise.) EMsmile (talk) 11:02, 9 December 2022 (UTC)
 * If someone wants to propose an image that goes back say 1,000 or 10,000 years that might also be a good solution. EMsmile (talk) 11:02, 9 December 2022 (UTC)

Removed content about Bern model
I've removed the following content about the Bern model as I judged it as being too detailed for this article: "A detailed model has been developed by Fortunat Joos in Bern and colleagues, called the Bern model. A simpler model based on it gives the fraction of remaining in the atmosphere as a function of the number of years after it is emitted into the atmosphere:


 * $$f(t)=0.217+0.338\exp(-t/18.51)+0.259\exp(-t/172.9)+0.186\exp(-t/1.186)$$

According to this model, 21.7% of the carbon dioxide released into the air stays there forever, but of course this is not true if carbon-containing material is removed from the cycle (and stored) in ways that are not operative at present (artificial sequestration)." EMsmile (talk) 12:49, 15 December 2022 (UTC) EMsmile (talk) 12:49, 15 December 2022 (UTC)

Suggestions for a modified structure
I recently had an in-depth discussion with an external expert about this article. It was with Pierre Friedlingstein from the University of Exeter (one of his publications is cited in the article). This review work took part in the context of this project. When we discussed the article we felt that at first glance, the article looked good. But when looking more closely, we feel that the article does not provide a narrative and guidance to the reader, but simply adds sentence after sentence of facts and figures, so that and one can hardly read it before feeling completely lost. Pierre suggested that the article structure and ordering could be changed and be made similar to the structure of the IPCC six assessment report, Working Group 1, Chapter 5 (here). EMsmile (talk) 14:43, 26 November 2021 (UTC)
 * So the structure could then be like this (very roughly): Pre-historical data, historical data (i.e. 1850 onwards), climate variability and budgets (emissions compared to sinks), future predictions (this would include content from the report's section 5.4 "Biogeochemical feedbacks", impacts on carbon cycles. However, in each section we would have to carefully think what kind of content is needed, given that there are existing other articles which cover related content, such as greenhouse gas emissions, global carbon cycle, climate change mitigation, climate change, greenhouse effect. EMsmile (talk) 14:43, 26 November 2021 (UTC)
 * One has to wonder whether an article called carbon dioxide in Earth's atmosphere should be very narrow and just talk about ppm of CO2, or broader and explain how the CO2 got there, what the consequences are, what could be done about it and so forth. Where exactly in the myriad of other climate change Wikipedia articles should this article fit? Narrow or broad? I would suggest perhaps "broad", but at a superficial level and refer to sub-articles whereever possible (maybe even use quite a few excerpts). What do you all think? EMsmile (talk) 14:43, 26 November 2021 (UTC)
 * Seems very good to me - go for it Chidgk1 (talk) 08:24, 29 November 2021 (UTC)
 * I'd like to move this along but worry that I am biting off more than I can chew. I think I need some help and guidance, or collaborators. The article is potentially very important (around 600 pageviews per day), so it would be good to get it into better shape. EMsmile (talk) 13:09, 14 January 2022 (UTC)
 * In finally found the time to come back to this article. I've done a bit of restructuring yesterday. I think the new structure works better, it is arranged a bit similar to the one on ocean acidification, i.e. in this order:

Current observations about CO2 and future trends Measurement techniques Causes for the current rise Role in greenhouse effect (keep it short) Role in carbon cycle (keep it short) Effects of current increase Proposed solutions (keep it extremely short) Concentrations in the geologic past Note the main difference to the structure before is probably that I have moved the information on the geologic past to the end of the article. I think this works better: first the present and future. Then at the end the geologic past. I do think that the interest of the majority of our readers would be in "what is happening now? why? what does it mean?". Only a small portion of readers (including climate change deniers?? (just a wild guess)) are more interested in what happened millions of years ago. I am even wondering if the content about the geologic past would be better off in a spin off article called Carbon dioxide in Earth's atmosphere in the geologic past? EMsmile (talk) 11:28, 9 December 2022 (UTC)
 * I've done more work on this article. The new structure is now like this:

1 Current concentration and future trends 2 Measurement techniques 3 Causes of the current increase 4 Roles in various natural processes on Earth 5 Effects of current increase 6 Approaches for reducing CO2 concentrations 7 Concentrations in the geologic past
 * Does anyone have any comments on this? EMsmile (talk) 10:51, 16 December 2022 (UTC)

Removed content about far future
I removed the below because it has been tagged for a long time as needing a better source:

"In billion-year timescales, it is predicted that plant, and therefore animal, life on land will die off altogether, since by that time most of the remaining carbon in the atmosphere will be sequestered underground, and natural releases of by radioactivity-driven tectonic activity will have continued to slow down.  The loss of plant life would also result in the eventual loss of oxygen. Some microbes are capable of photosynthesis at concentrations of  of a few parts per million and so the last life forms would probably disappear finally due to the rising temperatures and loss of the atmosphere when the sun becomes a red giant some four billion years from now. " Chidgk1 (talk) 16:38, 16 December 2022 (UTC)
 * I agree with that removal. I guess the paragraph could perhaps be moved to Future of the Earth (if it's not already there). EMsmile (talk) 23:00, 16 December 2022 (UTC)

Removed content about possibly higher 10,000 - 7,000 years ago
I removed the below as based only on a 20 year old primary source:

possibly higher 10,000 - 7,000 years ago
Based on an analysis of fossil leaves, Wagner et al. argued that atmospheric concentrations during the last 7,000–10,000 year period were significantly higher than 300 ppm and contained substantial variations that may be correlated to climate variations. Others have disputed such claims, suggesting they are more likely to reflect calibration problems than actual changes in. Relevant to this dispute is the observation that Greenland ice cores often report higher and more variable values than similar measurements in Antarctica. However, the groups responsible for such measurements (e.g. H.J. Smith et al. ) believe the variations in Greenland cores result from in situ decomposition of calcium carbonate dust found in the ice. When dust concentrations in Greenland cores are low, as they nearly always are in Antarctic cores, the researchers report good agreement between measurements of Antarctic and Greenland concentrations. Chidgk1 (talk) 18:10, 16 December 2022 (UTC)


 * You're probably right in removing this but it might be worth asking a content expert to take a look at it and tell us if it's WP:DUE and/or if it fits better into some other sub-article. Does anyone have access to a content expert? EMsmile (talk) 23:03, 16 December 2022 (UTC)

Parts per million and level
The lead qualifies parts per million by saying "(ppm, on a molar basis)". The section "Concentrations in the geologic past" refers to "a mixing ratio of 10−4 (100 parts per million by volume)". What is meant by mixing ratio - ?concentration?, and the statement of ppm by volume apparently contradicts the lead. Except that, I think I am correct in saying that ppm by volume and ppm by mole fraction are the same thing, and if so, the different qualifications are irrelevant and just lead to confusion. I am a biologist, not a physicist, so can anyone with a physics background please confirm this?. Secondly, in multiple places, the word "level" is used instead of concentration. Can we please use consistent terminology throughout the article? It is, after all a science article. Plant surfer 12:48, 17 December 2022 (UTC)


 * I have moved “ The concentration is expressed as "parts per million" (ppm, on a molar basis). “ down as I think it is too much detail for the lead. Hope someone else can solve your points. Chidgk1 (talk) 17:37, 17 December 2022 (UTC)
 * Replaced uncited definition of ppm with a cited one Chidgk1 (talk) 17:47, 17 December 2022 (UTC)
 * Removed “mixing ratio” as sentence is about methane not CO2 directly Chidgk1 (talk) 17:58, 17 December 2022 (UTC)
 * I’ll leave someone else to comment about whether “level” and “concentration” should be standardized Chidgk1 (talk) 18:01, 17 December 2022 (UTC)
 * Hi User:Plantsurfer and User:Chidgk1, thank you for coming to this article and helping with it. I was starting to feel a bit "lonely" here, just talking to myself so I am glad that you've showed up. This should be quite an important article and important to get right. so thanks! EMsmile (talk) 11:03, 19 December 2022 (UTC)
 * I've also wondered about "concentration" versus "level" in the past but was told they're synonyms, is that correct? See a short previous discussion on the talk page of the climate change article here: https://en.wikipedia.org/wiki/Talk:Climate_change/Archive_87#Usage_of_the_words_%22CO2_concentrations%22%3F . So I am not sure if "level" is meant to be easier to understand for lay persons than "concentration". It is a shorter word. I have a mild preference for "concentration". One could even ponder if the article title should be changed to "Carbon dioxide concentration in Earth's atmosphere" (but perhaps too long then). EMsmile (talk) 11:03, 19 December 2022 (UTC)
 * I don't intend to obsess about the use of level. It is certainly not a synonym of concentration. My point is that it can be used in the sense of "sea level" to indicate a horizontal plane, or to mean a position on a scale. So in the former case, if we were to discuss concentrations at different altitudes in the atmosphere, level would become ambiguous. If used in latter sense, it is always necessary to specify what kind of scale the level is on, i.e. height, temperature, velocity, mass, partial pressure etc.  Plant surfer  14:02, 19 December 2022 (UTC)
 * It seems to me that in "common language", level and concentration are used interchangeably, like "the level of CO2 in the atmosphere is rising". See how it's used at climate change. But I am not really sure, and could also be convinced otherwise. Perhaps ask also at the talk page of climate change? That talk page is always quite active and often good responses are offered there. EMsmile (talk) 14:45, 19 December 2022 (UTC)

‰ Is right?
Can somebody check this? 0.04‰ 421 ppm, 421*100/1000000 = 0.0421% not 0.0421‰

~ Spark 23 (talk) 16:15, 29 April 2023 (UTC)
 * you are correct: 421 ppm = 0.421 parts per thousand = 0.0421 percent  Plant surfer  16:31, 29 April 2023 (UTC)
 * @Klokonmr surprised you even have that on your keyboard - corrected Chidgk1 (talk) 16:33, 29 April 2023 (UTC)

Some remaining questions in my mind
I have some remaining questions, after I had done the reworking of the article in December last year (see comments above on this talk page). I had asked them to a content expert who had helped me in the past but no answer yet so I am putting them here in the hope that they can be addressed by someone in future:

My question to you today: could you please take another look at the new article now and tell me what you think? In particular what do you think of the new structure? Note that this article is only one of many climate change articles on Wikipedia, and therefore should not go into too much detail about adjacent topics, like the carbon cycle, photosynthesis, greenhouse gas emissions (in general) or the carbon budget. But it should provide a good overview and point people to the right sub-articles where needed. It should pull everything about CO2 concentrations in the atmosphere together in a concise manner. Some specific questions:
 * 1) What do you think of the new (current) structure?
 * 2) I am actually still wondering how I could introduce the connection to the carbon budget topic better.
 * 3) I think there might also still be some paragraphs in the article that are outdated or tangential and that could be cut. (e.g. is this section still up to date?: https://en.wikipedia.org/wiki/Carbon_dioxide_in_Earth%27s_atmosphere#Analytical_methods_to_investigate_sources_of_CO2)
 * 4) Also, have I missed out any key pieces of information from the technical summary of the WG I report?
 * 5) And have I identified the direct effects correctly by saying: Direct effects of increasing CO2 concentrations in the atmosphere include: increasing temperatures on land and in oceans, ocean acidification and a CO2 fertilization effect on plants and crops.
 * 6) For the indirect effects, I am pointing people to the article effects of climate change - that should suffice, right? EMsmile (talk) 12:43, 11 May 2023 (UTC)