Talk:Sea level rise

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Maximum possible sea level

I came to this page with the question: if all of the ice on earth was to melt, how much would sea level change. There is a lot of really great information on this page, but if my question is answered I was unable to find that answer. There is a lot of "if this" and "depending on that" and speculation and guesswork, but it seems like mine is a fairly simple and straightforward question. Hopefully someone knowledgeable can correct this omission or if it is there, make it somehow more obvious. Please don't consider this as a nasty criticism so much as a way to make a good page even better. FatBear1 (talk) 04:04, 26 September 2023 (UTC)[reply]

I came across a sentence in the ice sheet article which said it would be 58 m. See here: https://en.wikipedia.org/wiki/Ice_sheet#Antarctic_ice_sheet If it's not already in the sea level rise article, it could be added, I guess. Would you like to give that a go? - Oh wait, I see we have this sentence already: "The available fossil fuel on Earth is enough to ultimately melt the entire Antarctic ice sheet, causing about 58 m (190 ft) of sea level rise." Should we make it clearer / more prominent, perhaps also mention it in the lead? EMsmile (talk) 07:24, 26 September 2023 (UTC)[reply]
Thank you. I actually did see that 58 meters in this article, but found it ambiguous as it pertains to the question of all ice on earth melting. Should we assume that the last ice on earth will melt off of Antarctica with the final sea level 58 meters above current level? That might be reasonable, but a novice like me doesn't know that. Or does it mean that the melting of Antarctic ice will contribute 58 meters to sea level increase, but that other ice sheets will make their own contribution?
This is a well researched high quality article and even if I do learn the final answer, I'm not sure I could make the changes in a quality way. I'm not being lazy or a coward. I've written and modified many Wikipedia articles that I did know something about or which needed someone to get them started. If the answer does become clear to me and nobody else will make the change, I will attempt it. But someone here probably already knows the answer and can do a better job of it than I can. FatBear1 (talk) 16:29, 26 September 2023 (UTC)[reply]
I happened to come across some more content about this in the climate apocalypse article. There it was written like this: As temperatures increase, glaciers and ice sheets melt and the ocean expands which causes a rise in sea levels. Sea levels have risen by about 23 cm since 1880 and are currently rising at around 3.2 mm each year.[1] It is difficult to predict amounts of sea-level rise over the next century, although the ice sheets are melting earlier than predicted which makes a high-end scenario of 2 metres of sea-level rise by 2100 increasingly plausible.[2] If the entire Greenland ice sheet were to melt, the world's oceans could rise by more than 6 metres.[3] In the past, at times when the Earth has been 6°C above the pre-industrial baseline, sea levels were 20 metres higher than today.[4] If all the ice on land and at the poles melted, sea levels would rise by more than 65 metres.[3] EMsmile (talk) 08:25, 18 October 2023 (UTC)[reply]

References

  1. ^ "Sea level rise, explained". National Geographic. 2019-02-19. Retrieved 2020-01-02.
  2. ^ "Sea Level Rise Will Flood Hundreds of Cities in the Near Future". National Geographic News. 2017-07-12. Retrieved 2020-01-02.
  3. ^ a b "Global Catastrophic Risks 2018" (PDF). Issuu. Retrieved 2019-12-21.
  4. ^ Climate Change: What Happens If The World Warms Up By 5°C?, retrieved 2019-12-20

Spring back

While I was here and reading about the ice sheets it occurred to me: 10,000 feet of ice resting on Greenland is really heavy and is significantly depressing a large piece of the earth's crust. When that ice melts, the crust will spring back upwards. This is a well understood process when glaciers recede, but I think it will be significant in the case of such a large ice sheet as Greenland (or Antarctica). That upward springing land will displace water and will cause additional sea level rise around the world. I'm curious if anyone has figured out how to estimate that and how much they think it will be. FatBear1 (talk) 04:04, 26 September 2023 (UTC)[reply]

Ocean Heat Content Rise Graphic

More recent graphic

Showing a dead link at {79}. There are more up to date graphics out there and the link has migrated to ? How about changing out the graphic and link to a newer version. GeoSample (talk) 16:55, 26 October 2023 (UTC)[reply]

I hope you agree that the graphic at right is a good replacement. —RCraig09 (talk) 17:08, 26 October 2023 (UTC)[reply]

Arguments against causes of sea level rise

i noticed that arguments against the causes of sea level rise are not provided. For the sake of a balanced article, it would be better to add objections to the listed causes, especially man-made causes 105.113.105.228 (talk) 09:22, 22 November 2023 (UTC)[reply]

Like which ones? With reliable sources please. EMsmile (talk) 09:53, 22 November 2023 (UTC)[reply]

Readability edits and taking out older content?

I'm going to be working in the coming weeks on the Sea level rise article with a view to making it more readable. (This is part of the research communications project that deals with SDG 13 (action on climate change) administered by Stockholm Environment Institute (SEI) and funded by the Swedish government research council for sustainable development Formas. I've noted the discussion here and in the preceding sections about length. So I'll also try and shorten it, including the lead. I'll do this from a readability rather than substance perspective. So feel free to reverse any deletions that you think remove important material. Comments welcome.Jonathanlynn (talk) 11:02, 10 January 2024 (UTC)[reply]
Further to this I've now edited the Observations and Projections sections. I’ve removed some of the material from the “Projections for the 21st century” subsection concerning the reaction to the previous (2013-14) IPCC report AR5. (These are the 2017 University of Melbourne study and the 2017 fourth US national climate assessment. Also the very number-heavy discussion of studies  contrasting with Jim Hansen’s 2016 paper.) This material seems less relevant now that we have the IPCC’s SROCC and AR6 providing an up-to-date assessment of all research. It also struck me as too technical for the article. In the Post 2100 sea level rise subsection I removed the 17-83% range from some of the ranges.
This does reduce length, but editors who disagree may wish to revert the changes.Jonathanlynn (talk) 13:38, 10 January 2024 (UTC)[reply]
Thanks for the edits. Agree this page should contain the most current and immediately applicable information, but I do feel there is merit to keeping the old information elsewhere, perhaps Climate model#History. I do wonder if there is merit to a standalone article on the history of sea level rise predictions, alone or together with other climate change-related predictions [1][2], but that's a much longer term step. CMD (talk) 02:29, 11 January 2024 (UTC)[reply]
Interesting question. For now, I've put the text blocks of the older predictions back in at the very end of the article - awaiting consensus on talk page whether this should be deleted completely or moved elsewhere for archiving purposes? @Jonathanlynn: where these the only two text blocks that you cut out? EMsmile (talk) 12:10, 12 January 2024 (UTC)[reply]
I don't think that was a good idea. Firstly, my impression was that the main issue happened to be with the size of the entire article, so removing material from one section only to place it in another does not really help. Secondly, those predictions aren't really "old" at all when compared to a typical citation in a climate change paper - let alone to the 2000s (and sometimes older still) research which is still cited on its own across far too many articles here. In fact, implying that extensive analytical work as recent as 2020 is something which already needs to be "archived" is really counterproductive in my view.
Now that I am more-or-less done with updating the three ice sheet articles, I decided to simplify the section in a different way, by mentioning the AR5 and AR6 predictions next to each other, and simply mentioning fewer details about the other projections beyond how they differ from the IPCC.
I have also tightened up the parts on both of the Antarctica ice sheets, again based on the work I have been doing. InformationToKnowledge (talk) 20:10, 13 January 2024 (UTC)[reply]
That sounds like a good solution. (I didn't plan for my new "archive section" to stay for long; it was more of a "parking spot" to put those text block back in which User:Jonthanlynn had taken out. If you found a way of condensing this info without losing content then all the better. Thanks!). EMsmile (talk) 21:46, 14 January 2024 (UTC)[reply]
Coming back to the discussions here and elsewhere about length, it seems to me the simplest solution would be to remove the bulk of the very long "Regional impacts" subsection in "Impacts" to a separate article. A much shorter section with a highlight for each region could be retained in this main article to provide readers with immediate regional information and links to where to find more. Jonathanlynn (talk) 15:17, 2 February 2024 (UTC)[reply]
(To be clear I'm not proposing to do that myself and will edit that section for readability as part of my overall work on the whole article.) Jonathanlynn (talk) 15:20, 2 February 2024 (UTC)[reply]
Well, it's a fair suggestion, but the issue is the same as it was before - a sub-article just for the regional projections will likely languish with very low views and few updates and not be very useful. Moving much of the information to the specific regional pages is more reasonable, but the problem is in their poor state.
Most notably, the largest part of Regional impacts is the Asia section, yet Climate change in Asia does not actually exist - that link redirects you to a fairly poor two-paragraph summary in the actual Asia article, and then it suggests you either go to (yes, a link to a category as a "Further information" link or to other subarticles, most of which also do not exist (Climate change in Southeast Asia and Central Asia links just lead you to single paragraphs in those articles, "Climate change in East Asia" is a disambig for "Climate change in East Asian country" pages and "Climate change in North Asia" is a redirect to Climate change in Russia). It seems like if we want to move content out of here, actually creating Climate change in Asia would be a necessary prerequisite. Africa and Europe sections could also do with moves, and Climate change in Africa/ Climate change in Europe at least exist, though both are fairly bloated messes.
TLDR; Someone eventually needs to step up on those regional articles in general and the Asia article in particular. InformationToKnowledge (talk) 15:48, 2 February 2024 (UTC)[reply]
Predictably, that "someone" ended up being me. Grumbling aside, we finally do have Climate change in Asia article, so there finally was a space for many of the details in this article!
While I was at it, I did something similar with the Africa section (it helped that Climate change in Africa got better somewhat, though it is still really not great). Now, this article is finally below 10k words for the first time in forever! Amongst the other things, this also means that a key hurdle to nominating this for FA is gone. InformationToKnowledge (talk) 09:14, 8 May 2024 (UTC)[reply]

Suggestion to cull content on WAIS

I've just made a bold edit and suggestion: let's cut this one and move it to West Antarctic Ice Sheet if it's not already there (pinging User:InformationToKnowledge as they have recently worked and updated the West Antarctic Ice Sheet: is it OK to condense the WAIS content here a bit and point people to the other article for more info?. I think this is a bit too detailed here, using only primary sources, for this high level article that is already very long: 

++++++++++

Marine ice cliff instability, a related phenomenon observed in geological records but which has not yet been directly observed, occurs when ice cliffs with heights greater than 100 m (330 ft) collapse under their own weight once they are no longer buttressed by ice shelves. This is thought to create a self-sustaining retreat, where, after an ice cliff collapses, further ice behind it is to the same instability, creating rapid loss of ice on a larger scale than has ever been previously observed. However, this theory is controversial, has never been directly observed by humans, and is only supported by geological records.[1] Recent research has highlighted the importance of glacial geometry in preventing or contributing to marine ice cliff instability.[2] EMsmile (talk) 17:39, 28 April 2024 (UTC)[reply]

References

  1. ^ Wise, Matthew G.; Dowdeswell, Julian A.; Jakobsson, Martin; Larter, Robert D. (October 2017). "Evidence of marine ice-cliff instability in Pine Island Bay from iceberg-keel plough marks" (PDF). Nature. 550 (7677): 506–510. doi:10.1038/nature24458. ISSN 0028-0836. Archived from the original (PDF) on 6 May 2020.
  2. ^ Perkins, Sid (June 17, 2021). "Collapse may not always be inevitable for marine ice cliffs". ScienceNews. Retrieved 9 January 2023.

EMsmile (talk) 17:39, 28 April 2024 (UTC)[reply]

Well, I had a mention of this process before, but it was then expanded to this size by @Curlsstars:, who clearly feels strongly about it. The thing is, it really is potentially hugely important, and is the main reason why some projections are so much higher than the IPCC median. However, it is also really uncertain: Curlsstars' edits seem to assume that the one paleoclimate study from West Antarctica is adequate proof, but not even the two modellers who invented the hypothesis think that way!
So, I ultimately decided to add a couple of paragraphs to briefly summarize the hypothesis, the reasons it's controversial and the suggested way of resolving the question (outside of seeing it directly, obviously, which would hopefully not happen.) To compensate, enough material was condensed to still keep this within 10k words. After all, now that two new graphics show how much certain projections exceed the IPCC and we explain the reason why, we no longer need to devote as much space to certain primary projections. InformationToKnowledge (talk) 16:59, 1 June 2024 (UTC)[reply]
Seems good! I'm mostly trying to improve references, particularly access to live/archived links, and adhere content to those references cited, and so was applying that approach more than familiarity with knowledge of the science. If it seemed agendized, I apologize, as I'm generally less neutral in my offsite writing than is good practice for Wikipedia. Appreciation for the nuance expressed in these sections, it has greatly improved the article, and would have been beyond me to contribute. Curlsstars (talk) 16:43, 3 June 2024 (UTC)[reply]
@Curlsstars Great, I am glad that we have an agreement and ultimately improved this article a lot!
One last thing: I should say that we are actually not usually supposed to add URL links to journal citations. See Help:Citation Style 1: It is not necessary to specify a URL to a link identical to a link also produced by an identifier. The |url= parameter (or |title-link=) can then be used for providing a direct deep link to the corresponding document or a convenience link to a resource that would not otherwise be obviously accessible.
Essentially, what that means is that we only use |url= when the article is paywalled but there is a pdf of it available elsewhere, such as whiterose or the like. Otherwise, URL does the exact same thing as DOI and is therefore unnecessary. I realized this a while back, after I noticed that the citation bots have actually been removing URLs from the journal references I added earlier (while adding bibcodes, pmcs and the like.) If you ask on the talk page there, I'm sure they'll tell you the same.
You are not the only one who makes this mistake, to be fair: I noticed @RCraig09 has been doing the same thing (in addition to his non-standard refname style which just tends to take up excessive space for no real gain.) InformationToKnowledge (talk) 06:43, 8 June 2024 (UTC)[reply]
@InformationToKnowledge: Do you think there is a single "standard" for a WP:REFNAME? —RCraig09 (talk) 17:07, 8 June 2024 (UTC)[reply]
There isn't, but there is a consistent academic citation style - "FirstAuthorLastNameYear" - which is immediately recognizable by just about anyone who had ever looked at a paper. It is also a style which other editors tend to use naturally, not just me. (Well, they can go further and add "et al/others" or 2nd author's last name for 2-author papers - all of which is how proper academic citation is meant to function, but generally only eats up space in refnames only us can see.)
Your style is not something I have seen any other editor use, and it results in large refnames with typically excessive detail (there is almost never a need to specify date down to the day). Your decision to use journal title instead of the author last name is not a good idea, IMO - not only does it create longer and less readable refnames, but when a paper is by a prominent author, or when the same scientist authored multiple papers but in different journals, that fact is more important to highlight in the refname than the specific journal. InformationToKnowledge (talk) 18:08, 8 June 2024 (UTC)[reply]

Can we update/replace File:Sea_level_rise_projections_for_the_21st_century.png?

- an editor-created graphic from 2013, whose creator has not been active since 2016.

Needless to say, it is really dated nowadays. It doesn't look very well either, as it is monochrome and very pale, to the point it's blown up to a disproportionate size in the article just to make it readable.

The question is: do we want to have someone like @RCraig09 create something similar but with the modern projections, or just ditch it outright in favour of an existing compatibly licensed graphic from one of those other studies? InformationToKnowledge (talk) 04:30, 26 May 2024 (UTC)[reply]

I remember it was a long time before I encountered a good graphic or data for long-term sea level rise for . If someone knows of a good source summarizing other sources' predictions, that is the kind of chart I could generate. Finding a source is the main task. —RCraig09 (talk) 04:40, 26 May 2024 (UTC)[reply]
a good source summarizing other sources' predictions So, the IPCC? I get what you mean, and after thinking I would never find it, I think this here is exactly what you are looking for. Recent (2022), comprehensive (82 projections) and reasonably easy to understand once you get what they mean by "families". (In fact, I'll probably end up rewriting at least one paragraph based on its explanations.)
It is also CC-BY, so in theory, we could just use this figure directly. I know you would say it's "too techy", but consider what is currently in place. To me, the main issue would be explaining all the acronyms (perhaps write our own explanations for the coloured lines in the massive empty space in the lower-right corner of the graphic, and leave the rest in place?) Once we deal with this, it should already be a huge improvement over the current graphic.
We could also use this graphic and/or this graphic, both of which are very recent and CC-BY. I don't think the first graphic is superior to the 2022 one, but the second one could be really helpful for explaining how sea level rise consists of four main aspects. We could also then move another graphic or two to the lead - if Climate change has multiple images in the lead, why shouldn't this article? InformationToKnowledge (talk) 06:22, 26 May 2024 (UTC)[reply]
Actually, I can't see including any of the three suggested charts in a layman's encyclopedia. "families, based on similarities in methods and data"? "Combining families and thresholds leads to three categories,"? They look like inclusions in a doctoral thesis. A good inclusion criterion on Wikipedia would follow from asking: What clear "takeaway" would a layman discover in looking at a chart? Here, the immediate solution is simply to remove the outdated chart. A related issue is that skeptics would look upon "82 projections" as proof that "scientists don't agree". —RCraig09 (talk) 00:30, 27 May 2024 (UTC)[reply]
As I said, to me the main issue was with the original labels being unclear for non-academics, and luckily the CC-BY license does not prevent us from trying to address that. Further, the original section on "Projections" was already not very approachable with its fairly long-winded (and mostly unreferenced!) explanations of terms like "semi-empirical". That is where the 2022 paper ended up very relevant.
I decided to be bold this time, as I really think the article is looking so much better with the new images now, and it is better-referenced as well. InformationToKnowledge (talk) 17:52, 28 May 2024 (UTC)[reply]
It seems you've replaced the friendly and understandable with the indecipherably techy . Can you imagine such a chart being included in Britannica? Remember our audience includes butchers and bakers and candlestick makers with whom we're trying to communicate, and not doctoral advisors whom we're trying to impress. —RCraig09 (talk) 20:37, 28 May 2024 (UTC)[reply]
But I haven't? That chart of yours is where it always was, over at Sea level rise#Post-2100 sea level rise. The chart I added is several paragraphs beneath it.
And I don't see how "there are four groups of two lines and they all go up over time - lines on the right always go up by more" is a hard message to grasp for anyone. The original graphic did have the issue of its acronyms being too hard for many readers to guess (not long ago, I would not have known that "TE" is thermal expansion either.) Now that I wrote all of them out in full, that issue is gone. InformationToKnowledge (talk) 13:27, 29 May 2024 (UTC)[reply]
Sorry I missed ; I must have been looking at a completely different article in a different tab.
Though they may be good for a technical review article, I'm finding and definitely too complex for laymen and too needlessly detailed for communicating the concepts described in their captions. The captions help a lot, but most readers will squint at the graphics and scratch their heads and move on—defeating the purpose of having a graphic rather than narrative text alone. And is ~somewhat overly complex, and misleading because of different vertical scales in left vs right columns. Generally speaking, rather than starting out by finding an interesting techy graphic and captioning what it teaches scientists, it would be better to start with an encyclopedia-level concept and then finding/creating a graphic that visually communicates that concept; that's what's difficult. —RCraig09 (talk) 17:33, 29 May 2024 (UTC)[reply]
Thanks for reminding me of the vertical scale difference for - I now added that to its caption.
And I think we can apply the converse of "not every reader has a tertiary degree" - not every reader is a "layman" either. Given how many graphics this article has, it's fine if a couple of them are more complex than the others - particularly if they are present next to paragraphs which already explain the more theoretical content which "butchers, bakers and candlestick makers" would likely skip over either way. (Since presumably, such people don't need the specifics of what melts where to increase abstract-sounding global sea level to the nearest cm - the impacts of what gets flooded where is what would matter to them, and those parts have very approachable illustrations.) InformationToKnowledge (talk) 17:09, 1 June 2024 (UTC)[reply]
P.S. Speaking of graphics - would you consider tweaking your  ? I have recently promoted Ice to GA, and this graphic is likely to appear on the front page soon as part of a DYK. This forced me to look at it closely and I think some colours are too faint and similar to each other. Most notably, I think you need to make the difference between Arctic melt, Antarctic melt and Ice shelf calving much, much stronger visually - I suspect a lot of the readers would not even spot that faint Antarctic line at the top, and would instead assume that the big faint blue line is the Antarctic and the small faint blue line is the Arctic, rather than Ice Shelf Calving.
Grounded ice sections could also do with more distinct colours (shades for the two ice sheets are way too similar), but since they are at least of a similar size recently, this isn't as much a priority as addressing the sea ice colours. InformationToKnowledge (talk) 17:16, 1 June 2024 (UTC)[reply]
Version 3 of is uploaded (1 June 2024). It's clearer, though it won't win graphics awards without starting from scratch.
Separately, to my knowledge there is no converse to WP:ONEDOWN on Wikipedia. In practice we can test the limits of understandability—if the added complexity adds to informative takeaways of non-pedantic knowledge rather than abstruse or puzzle-worthy data. —RCraig09 (talk) 19:50, 1 June 2024 (UTC)[reply]

Excessive cites and complexity in the lead

Great to see recent improvement to the article reflecting a balance between RCraig09's eye for accessibility & 'typical reader’' friendly approach, against I2K's outstanding scholarship. I thought maybe we could go a little further in simplifying the first para for the benefit of the less educated reader, and edited accordingly. Per not wanting to get in the way of editors who might be putting in the hard work to take this to FA, no objection to my edit being fully reverted without discussion, if it's not seen as an improvement. Except, it would be good not to put back the bit about polar glaciers, as including that sort of nonsense so prominently discredits our credibility and serves pro polluter interests. FeydHuxtable (talk) 22:09, 7 June 2024 (UTC)[reply]

I undid that revision; polar glacier is a term used by Britannica and there is also this Nature headline - and that's just from a cursory search. Think about it; how is it inaccurate to say that Thwaites Glacier is a polar glacier? Greenland's glaciers like Helheim might be a bit further away from the geographic pole, but according to the explicit definition supplied by Britannica, they would count as well. Not commenting on readability/citation count, since other editors are more focused on that anyway. InformationToKnowledge (talk) 06:33, 8 June 2024 (UTC)[reply]
I think the readability was improved, even though the new text was 't quite grammatically correct. For instance, there was a sentence starting with while, which didn't have a subclasses. —Femke 🐦 (talk) 06:48, 8 June 2024 (UTC)[reply]
@ I2K: No issue with the undo of my edit, though would have nice to see a follow up deleting "polar glaciers" or replacing with 'icesheets'. But the polar defence is unexpected. I thought I was quite clear that part of the lede is nonsense?
To clarify, no one's suggesting "polar glacier" isn't a valid term, or that Greenland's features can't be called polar on latitudinal grounds! The salient point is that polar glaciers suffer very little melting. As per your Britanica link: A polar glacier is defined as one that is below the freezing temperature throughout its mass for the entire year How can melt from perma-frozen Glaciers account for 23% of SLR? The nature headline is Geoengineer polar glaciers to slow sea-level rise. Hopefully you'll later agree it's amusing you picked out two of the best possible sources to prove why the 'polar glaciers' part of the lede is nonsensical.
While "polar glaciers" is self evident nonsense in this context, if one checks the source, it's also blatant false WP:OR and misrepresentation. Even in the abstract is says: Ocean thermal expansion, glaciers, Greenland and Antarctica contribute 42 %, 21 %, 15 % and 8 % to the global mean sea level This clearly say's glaciers contribution is 21% , not a total of 44% split between temperate & polar types. It's even more obvious if you read the body of the paper that it treats the Greenland icesheet as seperate from glaciers - e.g. "total land ice mass loss (from glaciers, Greenland and Antarctica)" On this note, the word temperate should ideally be removed from the lede too, some of the 21% will be from sub-polar glacier melt not temperate alone. Still, at least the 'temperate' WP:OR isn't obviously false at first glance even without consulting the source.
I understand you're optimistic on the outlook at a civilisational level, but even the most sanguine analyses accept climate change is already causing hardship in vulnerable parts of the world, and threatens to do so with even more severity in the near future. So it's not really on to respond to another editors' concerns about pro-polluter nonsense by doubling down with a "cursory search". Especially when we're talking about the first para of the lede, the only part of the article many readers will read. If you only have time for a cursory look, then on a topic as important as this, it may be best just not to say anything at all, rather than waste other editors time with half baked argument? Let me try to put this in a more helpful way. Having a fine mind is like possessing a high tier sports car. It's great, but at more risk of crash than a regular car if not driven carefully. I used to see this often with my 180 IQ X . When she got passionate about something, she could articulate half a dozen cogent lines of argument with astonishing speed. But they'd each include a tiny error, like Lord Keynes says "starting with a mistake, a remorseless logician can end up in bedlam.". This kind of thing can be advoided by not rushing to act or argue in the heat of passion, instead taking ones time to sympathetically look at the others point of view. Sometimes the super-genius can learn something from the layman. :-) Anyways, we're well into the discuss part of BRD, so it would be good if you could remove the nonsense WP:OR yourself or approve for others to make the edit? (Unless I've missed something in my analyses of course.) FeydHuxtable (talk) 09:44, 8 June 2024 (UTC)[reply]
Feyd: please focus on content, not on the contributor. We're all trying to improve the article and mistakes happen. You're correct about polar glaciers: the current lead is incorrect. Most of the loss on the poles comes from the ice sheets themselves. —Femke 🐦 (talk) 09:51, 8 June 2024 (UTC)[reply]
The edit in question seems to be this one. I'm not sure about the "Sea level rise is happening around the world" wording, but the general principle of dialing down on the stats/numbers in the opening paragraph seems a good one. CMD (talk) 10:20, 8 June 2024 (UTC)[reply]
Yes, can we please spend less time on drawing inferences from editing patterns and more time on double-checking what we think we know?
So, first and foremost, I would like to note how we got to that wording in the lead in the first place. I did not have anything to do with it: my edits to the lead on 16 July 2023 had that sentence at Human-caused climate change is predominantly the cause: between 1993 and 2018, thermal expansion of water contributed 42% to sea level rise (SLR); melting of temperate glaciers contributed 21%; Greenland contributed 15%; and Antarctica contributed 8%.
Then, though, @Jonathanlynn embarked on several rounds of well-intentioned simplification of this article. So, in August 2023, he changed it to say Melting temperate glaciers accounted for 21%, with Greenland accounting for 15% and Antarctica 8%. Then, this February, he changed it again to Melting temperate glaciers accounted for 21%. Within this, Greenland accounted for 15% and Antarctica 8%. - incorrectly stating that all the glacier loss occurs on the poles and that ice sheets consist of temperate glaciers! Unfortunately, neither me nor anybody else watching the page recognized the issue at the time. Thus, it was actually a significant improvement when an IP editor got us to this "polar glaciers" wording two weeks later, on February 19.
So, if you want to restore the wording which was in my July 2023 edit, or something similar, I would not object. Having said that, I would like to explain why I was not opposed to the previous wording either.
As per your Britanica link: A polar glacier is defined as one that is below the freezing temperature throughout its mass for the entire year How can melt from perma-frozen Glaciers account for 23% of SLR? The nature headline is Geoengineer polar glaciers to slow sea-level rise. - So...are you suggesting that Thwaites Glacier isn't melting? And yes, the Nature article most definitely refers to Thwaites, Pine Island and Greenland's Jakobshavn - see the version archived before the paywall went up. Possibly the most relevant quote:
The Jakobshavn glacier in western Greenland is one of the fastest-moving ice masses on Earth. It contributes more to sea-level rise than any other glacier in the Northern Hemisphere. Ice loss from Jakobshavn explains around 4% of twentieth-century sea-level rise, or about 0.06 millimetres per year. Jakobshavn is retreating at its front. Relatively warm water from the Atlantic is flowing over a shallow sill (300 metres deep) and eating away at the glacier’s base.
Now...
Most of the loss on the poles comes from the ice sheets themselves. - What do you mean by "ice sheets themselves?" Because, it's undeniable that literally all the ice loss from Antarctica is from the coastal glaciers.
Here is an article which explains it the best:
Greenland and Antarctica are gaining ice inland, but still losing it overall
Ice all around the coast of Greenland thinned drastically, due to warmer summer temperatures (SN: 9/18/19). But the most severe thinning happened on Greenland’s outlet glaciers, which are like “a whole bunch of little fingers that spread out into the ocean,” Gardner says. Where the tips of these glacial fingers poke out from between cold fjords and meet warmer ocean water, that water erodes the ice, causing the glaciers to flow out faster and thin inland. Greenland’s southern Kangerdlugssuaq and Jakobshavn glaciers have thinned most rapidly — by 4 to 6 meters of ice thickness per year. In Antarctica, warmer seawater not only melts glaciers, but it also melts the extensions of the ice sheet that float on the ocean, called ice shelves, which surround the continent.
Even in Greenland, where the ice sheet itself does melt seasonally, the glaciers are still responsible for between half of the losses
The remaining 1,938 ± 541 billion tonnes (49.7 per cent) of ice loss was due to increased glacier dynamical imbalance, which rose from 46 ± 37 billion tonnes per year in the 1990s to 87 ± 25 billion tonnes per year since then.
Or even two-thirds.
The mass loss is controlled at 66.8% by glacier dynamics (9.1 mm) and 34.8% by SMB (4.6 mm).
So, all the ice loss from Antarctica and at least half the loss from Greenland is from the coastal glaciers. Considering this, I didn't think Feyd's wording - Close to half of sea level rise results from thermal expansion of sea water, with melting glaciers and ice sheets the other main cause. - was good, and I really didn't like the decision to strip references from the first paragraph and only from the first paragraph, so I reverted it. InformationToKnowledge (talk) 11:22, 8 June 2024 (UTC)[reply]
Apologies I2K for how I've approached this. In the OP I wrote "no objection to my edit being fully reverted without discussion, if it's not seen as an improvement" exactly because I didn't want to waste your valuble time. I'm in awe of how much quality improvements you make to our articles.
It was just the polar thing I had a strong view on as that did & still does seem incorrect. The Nature article is about possibly artifically creating polar glaciers as a solution to SLR - which does rather suggest they can't be causing 23% of the problem. While the Nature article does indeed refer to Thwaites Glacier, it does not define Thwaites as a polar glacier. Thwaites is not a polar glacier in the salient sense here, exactly because it is melting like you say. As per our own definition  : The ice of a polar glacier is always below the freezing threshold from the surface to its base, although the surface snowpack may experience seasonal melting. As I think we all agree, the contribution of said snow melt is trivial - essentially polar glaciers do not melt, so can't contribute significantly to SLR. Indeed, they can even help mitigate it. Again, I'm sorry that some element of my wording here may have made the point harder to grasp than it should be. All your other points make sense I2K, I still prefer less or no cites in the lede, but it's fully valid to think otherwise. FeydHuxtable (talk) 11:59, 8 June 2024 (UTC)[reply]
There are multiple definitions of polar glacier it seems. Either it's a glacier at the pole, or a glacier below the freezing threshold. We should just stick to the source, and not talk about polar glaciers.
Apologies for saying a majority of ice melt comes from the ice sheets without verifying. On a skim, I can't find out if your sources say it's ice loss via glaciers (drainage) or only of the glaciers themselves. —Femke 🐦 (talk) 12:36, 8 June 2024 (UTC)[reply]
Indeed. As John Hicks said about definitions: "bad tools that break in our hands". Though as you'll know better than most, certain conversations cannot be productively had without definitonal clarity. Its the thermal state definition thats more common, at least in relevent literature, as per I2K's Britanica source. The current incorrect lede even sets the reader's expectations along those lines with the wiki link for temperate glacier. I guess part of my error was in assuming normally very sharp editors would not need an explanation of the various senses in which 'polar' is wrong.
I believe the source is saying the proportions are: Thermal expansion: 42% | Glacier melt: 21% | Ice-sheet melt (Greenland + Antarctica): 23% . With the other 14% coming from the net of snow mass change, variation in atmospheric water vapour, terrestrial water storage flows, permafrost melt, and potentially other unidentified factors. FeydHuxtable (talk) 13:48, 8 June 2024 (UTC)[reply]
After reading the entire source, it's not quite correct to say 23% comes from ice sheet melt. The 15% Greenland + 8% Antarcica figures are mostly from melting ice-sheets, but also to a small extent due to Greenland & Antarcica glaciers. (WCRP didn't want to seperate out the peripheal glacier contribution to Greenland & Antarcica figures, due to measurment limitations.)
It's probably non optimal to have wording too close to the source( Ocean thermal expansion, glaciers, Greenland and Antarctica contribute 42 %, 21 %, 15 % and 8 % to the global mean sea level ), as if we don't specificy what we mean by Greenland and Antarctica, the reader could see that as question begging. I guess that's part of why we had the good faith miss-representation from the IP. But defo TMI to fully specify in the first para of lede, and would be slightly false WP:OR to replace "polar glaciers" with "ice-sheets". So I'm just going to sum up 21 + 15 + 8 & present as melt from ice-sheets & glaciers. This also has the virtue of slightly simplifying the lede. FeydHuxtable (talk) 17:45, 9 June 2024 (UTC)[reply]
Sounds good :) —Femke 🐦 (talk) 18:39, 9 June 2024 (UTC)[reply]

Condense lead and main text?

How does everyone feel about the length of the lead and main text? Both are a bit on the long side (lead length is 646 words, article length is 61 kB). The biggest section is the one on causes, in particular the sub-section on West Antarctica. Personally, I think that bringing the size down to say 58 kB would be a worthwhile goal, and perhaps 500 words for the lead. Just wondering. EMsmile (talk) 13:46, 22 June 2024 (UTC)[reply]

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