Talk:Sea level rise/Archive 6

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Antarctica intro

The section on Antarctica states, "The Antarctic ice sheet mass balance is affected by snowfall accumulations, and ice discharge along the periphery. Under the influence of global warming, melt at the base of the ice sheet increases. Simultaneously, the capacity of the atmosphere to carry precipitation increases with temperature so that precipitation, in the form of snowfall, increases. Furthermore, the additional snowfall causes increased ice flow which leads to further loss of ice" - this is the conclusion from a 2012 reference, however, the paragraph is too vague, because it does not mention regional trends, article statements are too bold. prokaryotes (talk) 17:11, 15 January 2019 (UTC)

I will check the new source you've provided and see what needs updating. I'm not really keen on including regional trends as it seems too detailed to me, but if overview sources on SLR mention it, I will go along with those of course. Femkemilene (talk) 11:12, 16 January 2019 (UTC)

Melt at the base, snowfall, and ice discharge is varying regional, and also most of the mass loss is from water melting as I understand, unless there is a large breakup? And "..additional snowfall causes increased ice flow..", seems suspect, once you account for the natural mass changes of calving and snow accumulation. Maybe we just use newer studies (or a meta study?), and migrate mass balance changes to the mechanism section? prokaryotes (talk) 14:24, 16 January 2019 (UTC)

I've now been able to look in detail to the news article [1] and the new Rignot paper [2] which you have cited.

You stated that

1. Article statements are too bold. I think that you mean (please confirm)
   1. Statement on snowfall which increases with warming? AND
   2. The consequence of this: Additional snowfall causing increased ice flow"

      I'm not familiar with any study that contradicts this. It is consistent with simple ice dynamics modelling and models.. More mass on top of ice makes it flow faster... The cited study says: [3] "The underlying mechanism is simple and very robust"

2. (in the article) However, a 2019 study found no increases in snowfall accumulation in the interior of Antarctica.

   I don't think the statement is completely correct, as snowfall does seem to have increased over a longer period; the past 200 years (see the article from 2018: [4]). Models (f.i. the 2012 study) seem more consistent; when warming reaches the southern polar region, snowfall increases. The new article is based on one of the three techniques of measuring the mass balance, a study assessing all three is consistent with no recent increase in snowfall: [5].

3. (in the article) However, a 2019 study concluded that East Antarctica is also losing significant amounts of ice mass, the researcher Eric Rignot told CNN, "I did not expect the cumulative contribution of East Antarctica melt to be so large, melting is taking place in the most vulnerable parts of Antarctica...parts that hold the potential for multiple meters of sea level rise in the coming century or two."

   This contradicts with an earlier statement in the article: The East Antarctic Ice Sheet does not contribute much and scientists are not able to determine whether it gains or loses mass. Here I'm more keen to trust the meta-analysis that came out last years because it uses a variety of techniques.

Could you confirm that this is what you meant? Are you now convinced about snowfall causing more ice flow? We could change the sentence about snowfall accumulation to something like: While snowfall has increased over the last 200 years, in recent decades (1979-2017) is has remained fairly stable. Would you agree with that? Is it sufficiently relevant? It is okay if I remove the sentence on East Antarctica losing mass till this in confirmed by other techniques OR independent scientist form a consensus on the accuracy of this new article? Femkemilene (talk) 12:53, 20 January 2019 (UTC)

What i meant is that I find the notion that snowfall automatically increases ice flow could be better explained. Is this linear under an equilibrium ice sheet state, otherwise there wouldn't be an ice sheet. And warming and snowfall and ocean temperature, and sea ice, appear to be connected, which is also not very clear, since more recent years show a sea ice decline, and no increase of snowfall accumulation. Maybe I should rather say the present part we discuss here is too simplistic. Also it is possibly better to make a more definite distinction between interior and basins. prokaryotes (talk) 16:03, 20 January 2019 (UTC)

Explaining the mechanisms behind increased ice flow with increased precipitation seem off topic here and confusing to the 14-18 year audience I now keep in mind. This article is about sea level rise, not about ice sheet dynamics. We just summarize those things of ice sheet dynamics that are relevant for SLR. (To answer your question; ice flow could be exponentially increasing with snowfall but still be smaller than the additional snowfall, linear/exponential doesn't tell you about absolute numbers and how they balance). Feel free to edit ice sheet dynamics to add these details that are still being researched.

4. I don't see what distinction should be made between interior and (interior) basins. Why do we need to explicitly define them and where does it lead to confusion. What are concrete changes you would like to make.

I would appreciate it if you answer questions before raising new topics and that when you raise a new topic, you make clear what concrete change you would like to make. Could you stick to the numbering? Femkemilene (talk) 17:21, 20 January 2019 (UTC)

Notice that I can not read your numbering when editing which is a little confusing. 1) I would mention something along these lines, "Its annual net input of mass from snowfall is 2,100 Gt (gigatons = 109 tons), excluding ice shelves, equivalent to a 5.8-mm fluctuation in global sea level (2). In a state of mass equilibrium, accumulation of snowfall in the interior should balance surface ablation (wind transport and sublimation) and ice discharge along the periphery into the Southern Ocean." https://www.pnas.org/content/early/2019/01/08/1812883116#ref-6 2) Yes, this is in regards to more recent findings. 3) Only because somewhere else it is written contradicting, doesn't make it per se wrong. I am now done in offering my critical input here, I will maybe come back to this at a later time, I am not here to argue with you, just sharing my impression, one of the few who comment here at all. prokaryotes (talk) 17:57, 20 January 2019 (UTC)

Thanks for your clear answers :). (1) A statement similar to this one is already present in the introduction of the contributions sector (2) I will make the introduction sentence covering (1) more clear, stating explicitly that wind transport and melt are also part of the balance. (3) It doesn't make it completely wrong, but neither completely correct. The study said no increase over last decades, which CNN (or you?) translated to no increase at all..

I appreciate you commenting, but just trying to find a communication method that works for both of us and just encouraging you to keep your error rate low (everybody makes mistakes of course). Femkemilene (talk) 19:16, 20 January 2019 (UTC)

Re, you wrote, no increase over last decades, or no increase at all? Per the study, "Recent observations have shown that the ice sheet is losing mass along the periphery due the enhanced flow of its glaciers, at a rate that has been increasing over time, while there is no long-term trend change in snowfall accumulation in the interior" - "We find that the Antarctic Ice Sheet has been out of balance with snowfall accumulation the entire period of study, including in East Antarctica." prokaryotes (talk) 19:28, 20 January 2019 (UTC)

(edit conflict) Fair enough, the original authors were not precise in their statement either. The three studies referenced started in 1980, 1992 and 2003, so I wouldn't have used the words long-term here. Femkemilene (talk) 19:54, 20 January 2019 (UTC)

Re, you asked "It is okay if I remove the sentence on East Antarctica losing mass till this in confirmed by other techniques OR independent scientist form a consensus on the accuracy of this new article?" - Per NASA 2018 study, "East Antarctica has the potential to reshape coastlines around the world through sea level rise, but scientists have long considered it more stable than its neighbor, West Antarctica. Now, new detailed NASA maps of ice velocity and elevation show that a group of glaciers spanning one-eighth of East Antarctica’s coast have begun to lose ice over the past decade, hinting at widespread changes in the ocean." https://climate.nasa.gov/news/2832/more-glaciers-in-east-antarctica-are-waking-up/ I think it would be wrong to not mention it, since there is more research from others, ie in regards to Totten Glacier. This is pretty much consensus conclusion now. prokaryotes (talk) 19:51, 20 January 2019 (UTC)

I disagree with the statement that it's pretty much consensus. Both the NASA study (covering 1/8) and the Rignot study use the 'contributions' methodology I think (described in Rignot), while satellite methodology is pointing towards a possible increase in mass [6]. The NASA study is also in agreement with the satellite study, which states: "The approximate state of balance of the wider EAIS suggests that the reported dynamic thinning of the Totten and Cook glaciers85,86 has been offset by accumulation gains elsewhere87." Concretely, I think it is fair to include the study but not as the ultimate truth. So adding possibly before East Antarctica under the Antarctica subheading and summarizing study in East Antarctica subsubsection.Femkemilene (talk) 20:15, 20 January 2019 (UTC)

I did not read the IMBIE study, but it appears we talk here about apples and oranges, individual glaciers vs the entire ice sheet? Other studies with different measurements see for instance, 2015 https://www.nature.com/articles/ngeo2388 prokaryotes (talk) 20:26, 20 January 2019 (UTC)

Rignot and IMBIE are both about the entirety of Antarctica and mention East Antarctica separately, that's comparing apples with apples. Our current article states that Totten is experiencing accelerated growth, and we agree on that. What we do not agree on is what to include about East Antarctica as a whole. I think it is too early to definitely say it is losing mass as these studies don't fully agree. Femkemilene (talk) 20:32, 20 January 2019 (UTC)

Btw Rignot is also part of IMBIE and the cite you mention for your argument found mass gains in North East Antarctica, partly due to a 2009 snowfall anomaly. Rignot 2019, NASA 2018, or Greenbaum 2015 found Totten Glacier is losing mass, with the trend more so in recent years, and it seems fastest acceleration are now glaciers from Vincennes Bay.prokaryotes (talk) 20:47, 20 January 2019 (UTC)

Yes, as I said before we and all of our sources agree on Totten, and the loss of Totten's ice is already in the text. I'm just saying that when we have two conflicting studies on the WHOLE of antarctica, we can't side with just the latest one, especially since they use different techniques. Femkemilene (talk) 20:57, 20 January 2019 (UTC)

We don't have to side at all, we add the follow up conclusion. prokaryotes (talk) 21:18, 20 January 2019 (UTC)

I felt that by giving more space to this new study (including the long soundbite from the interview), we were choosing sides. Do you agree with the current version? Femkemilene (talk) 12:17, 21 January 2019 (UTC)

Good edits, though a) i feel that mention of Ocean changes affecting mostly the already discussed regions is missing. Something like this, "A group of four glaciers in an area of East Antarctica called Vincennes Bay, west of the massive Totten Glacier, have lowered their surface height by about 9 feet since 2008, hinting at widespread changes in the ocean." It could be added 1:1 since it is public domain released. b) Instead of the last sentence, "This is possibly compensated by accumulation gains in other parts of Antarctica." I would write, "This was at least until recently compensated by snowfall accumulations, especially in Northern parts of the continent. c) for some reason I cannot read the IMBIE study today (yesterday I had access), they also mention "We find large variations in and among model estimates of surface mass balance and glacial isostatic adjustment for East Antarctica, with its average rate of mass gain over the period 1992–2017 (5 ± 46 billion tonnes per year) being the least certain." Thus, it is a bit unclear how this really compares to the new Rignot study, and if the article currently correctly reflects these different mechanisms, and if we here correctly differentiate between model estimates, and observational conclusions. prokaryotes (talk) 16:24, 21 January 2019 (UTC)

Will answer more of your message later. If you don't have access to a university VPN, it is a shame that only illegal sites such as Sci-Hub exist to get access to publicly paid-for research with publishers making insane profits. Femkemilene (talk) 16:51, 21 January 2019 (UTC)

The the PDF at the AGU URL is open access, so it should be accessible. If not, the PDFs of this and many other papers are available online at Michiel van den Broeke Polar Meteorology, Utrecht University, Recent snowfall anomalies in Dronning Maud Land, East Antarctica, in a historical and future climate perspective. Paul H. (talk) 17:57, 21 January 2019 (UTC)

@P Thanks for structuring your answer in way that makes it easy to reply :) a) I think you can guess my response here now :P. I'd like to article to be about the main points of SLR, preferable with as little numbers as possible. Having read the article, I don't think this particular news article is sufficiently relevant on a global scale to SLR. Depending on the unknown topography, it might be an important region, it might not be. Let's mention this only when sources on GMSL mention it. b) I think (with my tired head) you mean to say here that first it was compansated and later it wasn't anymore. With the two contradicting studies covering a similar I don't think we can say that with certainty. (c) Rereading both studies in more detail again. The Rignot study compares itself with the IMBIE-2 analysis:

Our mass balance numbers are within errors of the IMBIE-2 multisensor assessment for the years 1992–2017 (10) for West Antarctica (−83.7 ± 8 Gt/y versus −94 ± 27 Gt/y) and the Peninsula (−28.3 ± 1 Gt/y versus −20 ± 15 Gt/y), but our overall losses are higher for Antarctica (168.9 ± 5 Gt/y for 1992–2017 versus 109 ± 56 Gt/y) because we report a loss for East Antarctica (−57.0 ± 2 Gt/y) versus a gain with a large uncertainty in the IMBIE-2 assessment (+5 ± 46 Gt/y) (Table 1). Our estimate is affected by uncertainties in ice thickness and SMB but the errors are low when estimating decadal trends. Improved SMB models and additional ice thickness data in East Antarctica would further reduce uncertainties.

I hadn't seen how low their own estimate of uncertainty is; quite impressive. The gravimetry measurements (green in fig1 of IMBIE) seem to indicate something else, so as long as these two independent techniques are not reconciled both studies should get equal space. I will keep an eye on further developments. Both studies use a combination of some observations with some modelling. Femkemilene (talk) 20:53, 21 January 2019 (UTC)

Re importance please watch this 2018 AGU talk, they point out how the potential attribution of this region amounts to 29 m slr equivalent. prokaryotes (talk) 21:53, 21 January 2019 (UTC)

A dedicated mechanism section?

The mechanism section is not a section described in any of our major sources. We have a section contributions in which we describe the mechanisms at play per contribution, so I see no value to deviate from our sources. Femkemilene (talk) 15:44, 16 January 2019 (UTC)

The possibility of rapid dynamic response to environmental change as a mechanism of rapid sea-level rise is a long-standing idea in glaciology (Mercer, 1978; Thomas and Bentley, 1978) Is the National Academy of Sciences one of our sources? https://www.nap.edu/read/13389/chapter/5#47 prokaryotes (talk) 16:44, 16 January 2019 (UTC)

I agree with Femkemilene, that an effective lean mean article would be better organized the way she proposes. NewsAndEventsGuy (talk) 17:33, 16 January 2019 (UTC)

Add Mechanisms into one place vote

The article had a mechanism section at least in 2018. I find it confusing to have content about mechanisms in many places, such as the section on contributions. The latest IPCC AR5 goes into details about mechanism, section 13.4.3.2 Dynamical Change, noting,"Observations suggest three main mechanisms by which climate change can affect the dynamics of ice flow in Greenland (Sections 4.4.3 and 4.4.4): by directly affecting ice loss (outflow) through the calving of icebergs and marine melt from marine-terminating outlet glaciers; by altering basal sliding through the interaction of surface melt water with the glacier bed; and indirectly through the interaction between SMB and ice flow. We assess the consequences of each of these processes."

• Yes Since the IPCC dedicates a section to explaining mechanism (at least for Greenland) the argument we don't have a source for this, is void. Thus, I vote to flash out the main mechanisms for sea level rise in a dedicated section, in regards to sea level and dynamic changes, additional moving newer results there, ie. sea-ice interactions. prokaryotes (talk) 18:17, 16 January 2019 (UTC)

I was made to understood talk pages shouldn't have votes, but move towards consensus with argumentation. Reading subsubsections 4.4.3 and 4.4.4 it is very clear that IPCC puts mechanisms of ice melt under a section heading of contributions (specifically: Projected Contributions to Global Mean Sea Level). I really don't understand what you would put under a section heading of contributions, if not also the mechanisms involved in those contributions. We agree that mechanisms should be put in one place, but I see no reason to deviate from IPCC and not put them under the contribution section. Similarly, the NCA also does not make some weird distinction between a 'contribution' section and a 'mechanisms' section, but instead have one heading with "12.2: Physical Factors Contributing to Sea Level Rise". In terms of newer result, please don't put out of proportion attention to them. We are not a newspaper and typically don't need quotes unless they have historical significance. Femkemilene (talk) 21:27, 16 January 2019 (UTC)

From WP:POLL, "When polls are used, they should ordinarily be considered a means to help in determining consensus.." Can you agree that we add a sub-section under contributions, instead of adding mechanisms in different places? The quote was an example to highlight the significance by our sources, since that was your main concern above. This discussion here is about putting mechanisms leading to sea level rise into one place. :To be more precise, since you agree above to add mechanisms into one place, can we agree to add the mechanism stuff into a sub-section under contributions (like the IPCC does)? Adding parts in different sub-sections of the contribution section is not what I would call one place. prokaryotes (talk) 22:35, 16 January 2019 (UTC)

Also we could name the section Dynamic changes, it would include the parts on thermal expansion, regional effects for isostatic rebound or subsidence, sea-ice interactions, for mass balance etc. prokaryotes (talk) 23:03, 16 January 2019 (UTC)

See WP:NOTVOTE NewsAndEventsGuy (talk) 23:03, 16 January 2019 (UTC)

Before I reply, I will try to summarize your three proposals, because they are as yet unclear to me. Do you want to following changes?

1. Have all mechanisms in one section and thereby merging the sections contributions and regional sea level
2. Change the name of the contribution section to dynamical changes OR change the (sub)section title mechanisms to dynamical changes.
3. (least clear to me) change subsectioning under the 'contributions' section, with at least one section 'dynamics' and possibly other sections as well.

I will reply assuming that my interpretation of your text is correct.

1. I think it is useful to separate regional sea level mechanisms and global sea level contributions. A point could be made that the regional sea level rise comes immediately after global contributions. However, the IPCC has a similar ordening as we currently have. First contributions (current & past separated), then GMSL projections, then regional SLR.
2. Dynamical changes are basically changes in flow (per definition). I do not know which section you would like to rename, but both are linguistically incorrect. Thermal expansion, subsidence, sea-ice interactions and mass balance are NOT dynamical changes (look at section 4.4.3: they only put machanisms impacting ice flow under the subsubheading 'dynamical changes')
3. This is not clear to me, but I feel strongly we should follow the IPCC in our subsections for the contribution section. Collect all mechanisms in an orderly fashion under the right subsection. Femkemilene (talk) 09:48, 17 January 2019 (UTC)

How a report is structured is usually not the blueprint for an article. The IPCC AR5 Chapter 13 on Sea Level is = Contribution section - Dynamic changes section (which is mostly about process mechanisms in relation to mass balance). So I do not understand your argument that this sorting is "linguistically incorrect", since you cite the same IPCC chapter I assume.

There are three ways to in cooperate this here a) Contribution section - Antarctica - Dynamic changes (or processes, or mechanisms at play...), then the same for Greenland and so on. b) Or, to have one such section which then lists Antarctica, Greenland, Glaciers. For the tectonic effects, and thermal expansion we do not really need this. c) as it is now, mention processes together with contribution - to make no distinction, which makes navigating, reading of processes more difficult. prokaryotes (talk) 13:36, 17 January 2019 (UTC)

Every inch a marathon. Let's back up. I am frustrated at the talk talk talk and still not being clear what P wants either. So to back up, F attempted to summarize P's proposal in three steps, saying

1. Have all mechanisms in one section and thereby merging the sections contributions and regional sea level

2. Change the name of the contribution section to dynamical changes OR change the (sub)section title mechanisms to dynamical changes.

3. (least clear to me) change subsectioning under the 'contributions' section, with at least one section 'dynamics' and possibly other sections as well.

It would help us all, P, if you simply focused and said "yes that's right" or "no, change this word and add this nuance". So for pity's sake let's just focus on the big picture summation without rehashing rearguing redefending reexplaining readvocating.... For right now, I'd simply like to know if F accurately summarized the big picture for your desired changes? Once we have all agreed on the statement of the proposal, then we can make progress discussing its pros and cons. NewsAndEventsGuy (talk) 14:07, 17 January 2019 (UTC)

(edit conflict) We are slowly getting there I see :). I do think that how different reports are structured is the only blueprint we have. Again, P misrepresents the IPCC report. Their section is Contributions - Greenland/Antarctica - Dynamical changes (and other subsubsection on surface mass balance)

Ps proposed sorting was incorrect because you proposed previously to put non-dynamical changes (f.i. thermal expansion) under a section of dynamical changes, a thing IPCC has not done.

Ps assertion that the dynamical changes section is mostly about processes in relation to the mass balance is also incorrect. Only 1/3 of the section is about the relationship between SBM and dynamical changes. The previous section is about the mechanisms around surface mass balance.

P still hasnt given me an answer to the questions what distinction you see between 'dynamics' (by which you seem to mean physical mechanisms) and contributions. I will again summarize my understanding (please do confirm) what you mean here to propose a way forward. Your definition of contributions is the number of cm SLR attached to these contributions. I think we might be able to organize the subsection and subsubsections under the contributions heading more clear, in line with your solution (a). We can first describe numbers and then mechanisms. To prevent 4 layers of sections and ugly short subsubsubsections, I propose we do not introduce a new level of headings for this.

I'm not in favour of putting all mechanisms under one heading within the section contributions (b). The dominant mechanisms over Greenland (with the temperature-height feedback dominant) is quite different from the dominant mechanism in Antarctica. Femkemilene (talk) 14:27, 17 January 2019 (UTC)

Is this a good place to use an WP:Embedded list?

A number of different geophysical processes can contribute to sea level rise. As explained in subsequent sections of this article, some have a more immediate or larger effect than others, and examples include

1 blah blah cite

2 In Greenland, blay slay cite

3 In Timbuktu, goo boo cite

Lean mean ruthlessly compact and short, with each being developed elsewhere in this article and for some this article might develop the thought in WP:SUMMARY while spinning off the long details to a sub article.

I am not advocating this approach, only suggesting it for consideration as a way forward

NewsAndEventsGuy (talk) 14:50, 17 January 2019 (UTC)

For clarification I suggest to exactly match the sorting of the IPCC report, so when I wrote Contribution section - Dynamic changes section, this should apply to each region (Antarctica, Greenland etc.). Initially I created the Mechanism section as a main section, to avoid too many sub-sections under the Contribution section. I don't think that focusing on details is very goal orientated, while the IPCC does not sort thermal expansion as a dynamic change, it clearly is one according to thermodynamics. The Dynamic sections are concerning mass balance in relation to melting processes, if you think otherwise fine, there is no need to discuss this detail.

On the one hand you refer to the IPCC report with the sub sections titled Dynamic changes, and use it as a blueprint, on the other hand you don't want to have these distinctions here, so you opt to keep the article as is, rather then to have additional sub sections for mechanisms, processes, dynamic changes (whatever you want to call it). We are now done sorting out opinions. You want to keep it as is now, with maybe some fine tuning, I want extra headings, or a dedicated section for this. So we are basically at the same point as initially. If someone has questions, again i refer to the IPCC report style of sorting/structuring, make it like there, make a distinction for better readability and navigation purposes. prokaryotes (talk) 15:03, 17 January 2019 (UTC)

Before we can continue this discussion, we should agree on a definition for dynamical. Within meteorology and oceanography the terms dynamical and thermodynamical are used in contrast with each other. See for instance all results in this google search: [7]. Simplified, this is the definition we use: [8]. The IPCC is correct in not sorting thermal expansion under dynamical changes. Femkemilene (talk) 15:59, 17 January 2019 (UTC)

The IPCC is discussing dynamic and thermodynamic processes under the heading called Dynamic changes, since they involve thermo-mechanical coupling. The IPCC thermal expansion section simply likely stands on its own since it is more predictable, I would assume. The IPCC report is using Dynamic changes interchangeably, unrelated to a constraint definition. prokaryotes (talk) 16:41, 17 January 2019 (UTC)

Can you confirm you understand the difference between the two? Of course, thermodynamical and dynamical processes can interact. I don't understand what predictability has to do with using the correct terminology. What do you mean by constraint definition? Femkemilene (talk) 17:00, 17 January 2019 (UTC)

Yes, the section heading does not present the definitions you cited. We discuss now the naming of the proposed section, which may be better discussed separately. To avoid any confusion we could it simply name Processes. prokaryotes (talk) 17:10, 17 January 2019 (UTC)

Also, ocean heat uptake has been recently linked to dynamic effects, see A recent increase in global wave power as a consequence of oceanic warming. So I guess the next IPCC report may very well include dynamical changes for this section as well. prokaryotes (talk) 17:16, 17 January 2019 (UTC)

If we include a new subsubsubheading, Processes, Physical processes or mechanisms would capture all processes you are referring to. I'm happy we've reached consensus on the meaning of dynamics. You have not given me an answer to my question what other things than physical processes you would like under the section heading Contribution. Is it the numbers of past and potential sea level rise? The IPCC has three subsections under their future contributions section for Greenland and Antarctica, ALL dealing with quantifying and describing physical processes. What else do you expect under contributions? Femkemilene (talk) 08:46, 19 January 2019 (UTC)

@P I think we can agree on the fact that the current structure of the article is quite bad: we have two different sections dealing with the physics (contributions & a small mechanisms section). Would it be okay if I merge the two, even if you think separating the two completely is better (I'm still not entirely clear what will be left over under contributions)? We have to choose either of our options and mine requires only tweaks while yours requires a difficult separation. Femkemilene (talk) 10:22, 24 January 2019 (UTC)

Yes, merge them. Thanks. prokaryotes (talk) 11:43, 24 January 2019 (UTC)

Thanks. Femkemilene (talk) 12:16, 24 January 2019 (UTC)

World Meteorological Organisation's "state of the global climate in 2018"

Some of the findings reported therein are likely relevant to the article and should probably be noted. See:

• https://www.independent.co.uk/environment/climate-change-sea-levels-rise-flood-malnutrition-un-report-a8844156.html
• https://public.wmo.int/en/media/press-release/state-of-climate-2018-shows-accelerating-climate-change-impacts
• https://library.wmo.int/index.php?lvl=notice_display&id=20799

Zazpot (talk) 22:45, 28 March 2019 (UTC)

21st century projections - first paragraph - treatment of ice sheet uncertainty

I'd like to float a rewrite for the first paragraph under "21st century projections". IPCC did not really provide an upper limit to projections and the main hedge (as in prior reports) was ice sheet dynamics. (For more background see this RealClimate 2013 blog post). To try to convey this in a smooth way, lets kick around something like this proposed substitute text (with citation polishing after we have consensus on the text)

In its fifth assessment report (2013) the Intergovernmental Panel on Climate Change (IPCC) said that it is "virtually certain that sea level will continue to rise during the 21st century and beyond." (REF IPCC AR5 WG1 Chap 13 pg 1205) For the 21st century, IPCC projected likely minimum sea level rise for different levels of greenhouse gas emissions. These 2013 projections only include factors for which there was scientific consensus and explicitly omit the possibility of marine ice sheet instability. (REF IPCC AR5 WG2 TS pg 63 Box TS.6) If countries make rapid cuts to emissions (the RCP2.6 scenario), IPCC projects that the known contributors will likely raise sea levels by 26–55 cm (10–22 in), and by 52–98 cm (20–39 in) for very high emissions (the RCP8.5 scenario). IPCC assessed its projections as "likely", meaning they have 67% confidence in these numbers, and they offer the following caution:

Although improved understanding has allowed the projection of a likely range of sea level rise during the 21st century, it has not been possible to quantify a very likely range or give an upper bound to future rise. The potential collapse of ice shelves, as observed on the Antarctic Peninsula (Rignot et al., 2004; Scambos et al., 2004; Rott et al., 2011), could lead to a larger 21st century rise of up to several tenths of a metre.

— IPCC AR5 WG1

Your comments? NewsAndEventsGuy (talk) 20:24, 30 July 2019 (UTC)

I've tried to keep the discussion of IPCC concise, as it's quite out of date already. This September, a new IPCC report on the cryoshpere and SLR will come out. Before that, I don't object to this addition, but please don't put much effort till the new report is out. Femke Nijsse (talk) 22:23, 30 July 2019 (UTC)

Great, I don't pay attention to things in the pipeline. I'll just paste this in and it can be sliced and diced whenever b whomever. NewsAndEventsGuy (talk) 22:55, 30 July 2019 (UTC)

refs for this thread

References

Projections

I don't claim the "Map of the Earth with a long-term 6-metre (20 ft) sea level rise" is completely incorrect and it states some of its limitation ("uniform distribution, actual sea level rise will vary regionally") but it has some glaring problems that make me question if it adds any informative value to the article.

The amount of red color seems to increase more by the length of the coastline under each pixel than the land area that would be inundated. If there is a lot of skerries, islands, bays or peninsulas within a pixel the area will glow bright red and makes it look lake it would become completely deluged. Norway for example has large areas in the north marked with red although those areas are very mountaineous and having peaks rising almost straight up from the sea. See for example this Google Streetview from Norway. Everything visible is marked with red in the map. Also, not taking glacial rebound into account adds another problem because it is countering the sea level rise around that area with about 100% margin at the moment. — Preceding unsigned comment added by 85.23.42.147 (talk) 21:05, 22 September 2019 (UTC)

Good point, I'll have a look at it later, and will try to find a replacement map! Maybe the new IPCC report tomorrow will give some inspiration. I might try and collect a few 'close-ups' of certain vulnerable regions in the world. A collection of maps of Bangladesh, Netherlands, Florida and Kiribati for instance. Femke Nijsse (talk) 21:14, 22 September 2019 (UTC)

Projections in the lede and elsewhere

Here's the second paragraph of the lede as currently written:

For example, in 2007 the Intergovernmental Panel on Climate Change (IPCC) projected a high end estimate of 60 cm (2 ft) through 2099,[6] but their 2014 report raised the high-end estimate to about 90 cm (3 ft).[7] A number of later studies have concluded that a global sea level rise of 200 to 270 cm (6.6 to 8.9 ft) this century is "physically plausible".[8][3][9] A conservative estimate of the long-term projections is that each Celsius degree of temperature rise triggers a sea level rise of approximately 2.3 meters (4.2 ft/degree Fahrenheit) over a period of two millennia (2,000 years): an example of climate inertia.[2]

The century-end projections used here are the high-end estimates and the most extreme "physically plausible" projection. In the apparent interest of providing balance, the paragraph then switches to providing a low-end estimate, but it is projected over the next 2000 years rather than only to century's end. In the interest of giving users the most accurate information possible (in a consistent way), shouldn't the lede provide in all cases: (1) the point estimate, which is the single best estimate, or (2) the upper and lower confidence limit on the projections, or preferably (3) the point estimate & the CLs?

Ditto for the "Projections for the 21st century" section. Why are some paragraphs written to provide an estimate of "up to ..." or "as much as ..." or "physically possible", whereas others do in fact provide the point estimates and/or CLs (not just the most alarming plausible value)? Is there an objective reason for providing the most alarming as opposed to the least alarming plausible values here?

Should these sections be rewritten to be more informative, unbiased, and consistent? Bueller 007 (talk) 23:41, 16 August 2020 (UTC)

Effects of dams in the 1970son sea-level rise

Perhaps someone can weave the following sources into the article. Apparently during the 1970s, peak dam construction slowed sea-level rise drastically. As researcher Thomas Frederikse put it, "We impounded so much freshwater, humanity nearly brought sea level rise to a halt."

• Jet Propulsion Laboratory (2020-08-23). "NASA Research Reveals the True Causes of Sea Level Rise Since 1900". SciTechDaily. Retrieved 2020-08-24.
• Frederikse, Thomas; Landerer, Felix; Caron, Lambert; Adhikari, Surendra; et al. (2020-08-19). "The causes of sea-level rise since 1900". Nature. 584 (7821). Springer Science and Business Media LLC: 393–397. doi:10.1038/s41586-020-2591-3. ISSN 0028-0836.

Peaceray (talk) 19:28, 24 August 2020 (UTC)

Really unfortunate wording

In case any of the page's owners care: The lede sentence "Between 1900 and 2016, the sea level rose by 16–21 cm (6.3–8.3 in) on average.[3]")\ makes it sound like sea level has risen 7 inches every year for over a century - i.e. over 70 feet. NASA says that about 7 inches is the TOTAL rise in that time frame, not the average. https://climate.nasa.gov/news/3012/nasa-led-study-reveals-the-causes-of-sea-level-rise-since-1900/
If you mean something esoteric like "averaged out over the entire surface of the earth", you really need to explain it. In the absence of a qualifier, people will reasonably assume "on average" refers to "Between 1900 and 2016" (the most logical antecedent). 2603:3023:39F:B800:BC71:CBAC:1966:3810 (talk) 10:16, 11 December 2020 (UTC)

Good catch! Reworded. Femke Nijsse (talk) 10:43, 11 December 2020 (UTC)

What is a "melt anomaly"?

I tried googling, but can't find anything. Thy, SvenAERTS (talk) 13:24, 4 February 2021 (UTC)

It's a difference with respect to a reference period. Removed it, as the caption is understandable without it. Femke Nijsse (talk) 13:28, 4 February 2021 (UTC)

Other ideas

Can some sections about coral dying due to ocean acidification and the "Third Pole" of the world (Tibet) melting be added? Also, I found something named floodmap.net while failing to find an interactive topographic map. It might warrant some reference. — Preceding unsigned comment added by 173.64.101.203 (talk) 22:18, 21 February 2021 (UTC)

Acidification is really an entirely separate thing. It is mentioned in the main climate change article as it obviously is a product of greenhouse gas emissions, but it's an entirely separate effect from sea level rise. Floodmap is pretty fun but is a paid commercial product so including it here would be iffy, particularly if it is just rendering government supplied data. --Efbrazil (talk) 03:30, 22 February 2021 (UTC)

Ocean or oceans and related discussions

This might seem like an academic discussion but this article (like many others) uses ocean (singular) and oceans (plural) interchangeably. I am currently involved in a discussion about the three articles Ocean, Sea and World ocean. I feel that I need more eyes and brains to contribute to that brainstorming. Recently it has been discussed to change the wording in the ocean article mostly to oceans, and this could affect this "sea level rise" article as well. Anyhow, please contribute to the discussion here. Also let me know what you think about ocean versus oceans here. Or leave an opinion here. My own opinion is that ocean (singular) is fine when talking about sea level rise, rather than oceans. And that ocean and oceans is used interchangeably these days. But would be interested to know how others feel. EMsmile (talk) 03:40, 4 March 2021 (UTC)

Could we settle on just one image for the lead?

I would prefer if we could settle on just one image for the lead. Currently we have three. As per WP:MOSLEAD: "It is also common for the lead image to be representative because it provides a visual association for the topic, and allow readers to quickly assess if they have arrived at the right page". I think the first image might be the best one, as it's not overly complicated. The caption should probably include which year this graph is current for. EMsmile (talk) 02:17, 10 March 2021 (UTC)

I have changed it now to just one image for the lead. EMsmile (talk) 14:23, 29 April 2021 (UTC)

Short description

Hi @Femkemilene! Per WP:SDFORMAT, we should be aiming for a target length of 40 characters or less. The current description is 87 characters, more than twice over that. I'll defer to your expertise about what word might be more appropriate than "ecological", but I don't think this is a page where it's necessary to go over the limit. Please keep in mind that short descriptions are intended to help with disambiguation, not to be a full mini-definition of the subject. Cheers, {{u|Sdkb}} ^talk 20:14, 11 June 2021 (UTC)

I had hoped my revert would lead to an explanation of what short descriptions are about :). FYI, ecological is about life, not about the environment in general. FemkeMilene (talk) 21:04, 11 June 2021 (UTC)

Remove "further reading" list?

I suggest to remove the "further reading" list. If there is anything really important in there, it should be included as an in-line citation. EMsmile (talk) 14:25, 29 April 2021 (UTC)

Further reading usually proves to be helpful for readers...

Further readings can help in providing pdf and books more precisely.

Would like to know your thoughts regarding this..? Me - Disha, India (talk) 12:30, 31 May 2021 (UTC)

Strong oppose The Further reading is a standard section, albeit optional. As the MOS:FURTHER guide states, The Further reading section should not duplicate the content of the External links section, and should normally not duplicate the content of the References section, [...].

As the Wikipedia:Further reading essay explains The Further reading section of an article contains a bulleted list of a reasonable number of works that a reader may consult for additional and more detailed coverage of the subject. I would advise all to read this essay, as many of the points it makes explain the reasons for maintaining a Further reading section in addition to the References & External links section.

The proposing editor has not stated reasons for removing this standard section that directs readers to relevant articles that offer further detail that is beyond the scope of the article. Peaceray (talk) 15:51, 31 May 2021 (UTC)

Most Wikipedia articles don't have a "further reading" section (like the essay states) and for good reason. Such a list is difficult to select fairly (given the huge number of publications nowadays) and to maintain. For example, looking at the current list, are you sure that they are all so relevant? Many of them are really old which for a dynamic topic like "sea level rise" is a problem. Also, the essay that you mentioned states "Preference is normally given to works that cover the whole subject of the article rather than a specific aspect of the subject, and to works whose contents are entirely about the subject of the article, rather than only partly." For most of the publications currently listed under "Further reading", this is not the case. Instead, they cover only small aspects of the overall topic. Some of them are not freely available which would make them inaccessible to many readers of this Wikipedia article anyhow. - Looking at the current list, do you think that ALL of them should really stay? Could we compromise by culling it down to the most suitable ones? EMsmile (talk) 16:01, 31 May 2021 (UTC)

I think that winnowing the list down to the more general citations would be good. After all, WP:Further reading also links to {{Further reading cleanup}}, a template that states Please ensure that only a reasonable number of balanced, topical, reliable, and notable further reading suggestions are given; removing less relevant or redundant publications with the same point of view where appropriate. Peaceray (talk) 17:09, 31 May 2021 (UTC)

I am more of the opinion of EMsmile on this one: the current list is not very current, and very mixed -- the problem with Further reading in Science articles is that the science changes so quickly, that it quickly becomes outdated or irrelevant. If we don't have a good reason to cite those works, I think we should cut them. Sadads (talk) 17:39, 31 May 2021 (UTC)

Happy with cutting it. I winnowed it down for the GA nomination years ago iirc, but did not really update it much. FemkeMilene (talk) 17:41, 31 May 2021 (UTC)

Sounds good to me. Peaceray, ls there one in this list that you say needs to be kept in particular? I have crossed out the ones which I think quite clearly are not worth keeping in this list (this is not to say that they couldn't be used as in-line citations):

• Byravan, Sujatha; Rajan, Sudhir Chella (14 April 2011). "The Ethical Implications of Sea-Level Rise Due to Climate Change". Ethics & International Affairs. 24 (3): 239–260. doi:10.1111/j.1747-7093.2010.00266.x. S2CID 145462401.

*Menefee, Samuel Pyeatt (1991). "'Half Seas Over': The Impact of Sea Level Rise on International Law and Policy". UCLA Journal of Environmental Law and Policy. 9 (2). * Warrick, R.A.; Provost, C.L.; Meier, M.F.; Oerlemans, J.; Woodworth, P.L. (1996). "Changes in sea level". In Houghton, John Theodore (ed.). Climate Change 1995: The Science of Climate Change. Cambridge, UK: Cambridge University Press. pp. 359–405. ISBN 978-0-521-56436-6. *Church, J. A.; Gregory, J. M.; Huybrechts, P.; Kuhn, M.; Lambeck, K.; Nhuan, M. T.; Qin, D.; Woodworth, P. L. (2001). "Changes in Sea Level". In Houghton, J.T; Ding, Y.; Griggs, D.J.; Noguer, M.; Van der Linden, P.J.; Dai, X.; Maskell, K.; Johnson, C.A. (eds.). Climate Change 2001: The Scientific Basis: Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel. pp. 640–694. hdl:10013/epic.15081.d001. * National Snow and Ice Data Center (February 19, 2018), "Contribution of the Cryosphere to Changes in Sea Level". Accessed October 7, 2018 * Maumoon Abdul Gayoom. "Address by his Excellency Mr. Maumoon Abdul Gahoom, President of the Republic of Maldives, at the nineteenth special session of the United Nations General Assembly for the purpose of an overall review and appraisal of the implementation of agenda 21 – June 24, 1997". Archived from the original on June 13, 2006. Retrieved 2006-01-06.

• Pilkey, O.H.; Young, R (2009). The Rising Sea. Shearwater. ISBN 978-1-59726-191-3.

*Douglas, Bruce C. (July 1995). "Global sea level change: Determination and interpretation". Reviews of Geophysics. 33 (S2): 1425–1432. Bibcode:1995RvGeo..33.1425D. doi:10.1029/95RG00355. *Williams, Angela (October 2008). "Turning the Tide: Recognizing Climate Change Refugees in International Law". Law & Policy. 30 (4): 502–529. doi:10.1111/j.1467-9930.2008.00290.x. S2CID 154078944.

• "Why does sea level rise threaten marine ecosystems?". Marine Conservation Institute. Retrieved 2018-10-07.
• Horton, Benjamin P.; Khan, Nicole S.; Cahill, Niamh; Lee, Janice S. H.; Shaw, Timothy A.; Garner, Andra J.; Kemp, Andrew C.; Engelhart, Simon E.; Rahmstorf, Stefan (2020). "Estimating global mean sea-level rise and its uncertainties by 2100 and 2300 from an expert survey". NPJ Climate and Atmospheric Science. 3 (1). doi:10.1038/s41612-020-0121-5. ISSN 2397-3722.

EMsmile (talk) 03:38, 1 June 2021 (UTC)

As this discussion seemed to have come to an end (didn't see a reply from Peaceray?), I have now culled the "further reading" list down to just three items. Do we even need those three? I am not too sure. EMsmile (talk) 13:17, 13 June 2021 (UTC)

Melting glaciers and rising coastal waters between 1900-2017

What were the changes between 1800-1917 and 1700-1817? 140.82.139.100 (talk) 02:08, 6 January 2022 (UTC)

The following text block about sea level rise was recently deleted at effects of climate change

The following text block about sea level rise was recently deleted at effects of climate change by User:Chidgk1. It's been replaced with an excerpt from this article. I am just wondering if there was any content in this text block that would be worth salvaging? Probably not but I just thought I'd ask.

Historical sea level reconstruction and projections up to 2100 published in 2017 by the U.S. Global Change Research Program

The IPCC's Special Report on the Ocean and Cryosphere concluded that global mean sea level rose by 0.16 metres between 1901 and 2016. The rate of sea level rise since the industrial revolution in the 19th century has been larger than the rate during the previous two thousand years.

Global sea level rise is accelerating, rising 2.5 times faster between 2006 and 2016 than it did during the 20th century. Two main factors contribute to the rise. The first is thermal expansion: as ocean water warms, it expands. The second is from the melting of land-based ice in glaciers and ice sheets due to global warming. Prior to 2007, thermal expansion was the largest component in these projections, contributing 70–75% of sea level rise. As the impact of global warming has accelerated, melting from glaciers and ice sheets has become the main contributor.

Even if emission of greenhouse gases stops overnight, sea level rise will continue for centuries to come. In 2015, a study by Professor James Hansen of Columbia University and 16 other climate scientists said a sea level rise of three metres could be a reality by the end of the century. Another study by scientists at the Royal Netherlands Meteorological Institute in 2017 using updated projections of Antarctic mass loss and a revised statistical method also concluded that, although it was a low probability, a three-metre rise was possible. Rising sea levels will put hundreds of millions of people at risk in low-lying coastal areas in countries such as China, Bangladesh, India and Vietnam. EMsmile (talk) 09:04, 9 February 2022 (UTC)

References

Move content from "Effects of climate change on oceans"?

I am just trying to reduce overlap for related articles: In the article Effects of climate change on oceans there is a section on sea level rise. I have now added an excerpt there but there is more content about sea level rise at that article which I would be inclined to move to here instead. I have not yet checked if it's good content and up to date. What do you think? Please check here and scroll below the excerpt part. EMsmile (talk) 04:23, 18 August 2021 (UTC)

A quick glance at that article shows content that doesn't meet GA criteria with respect to MOS, up-to-dateness and neutrality (very focussed on the US). You'd probably have to almost start from scratch. At places, it reads like an essay. FemkeMilene (talk) 17:22, 18 August 2021 (UTC)

Thanks for your assessment, Femkemilene, much appreciated. How about this approach: I first try to weed out what reads like essay like material and then I move the rest of it (especially anything US focused) to Climate change in the United States. In the end, only the excerpt of "sea level rise" would then stay behind in the article Effects of climate change on oceans#Sea level rise. I usually try not to delete big chunks of text (I guess I am a WP:inclusionist) but tend to move text blocks to the more specialised sub-sub-articles where they might add value. However, with some of the climate change stuff this might be problematic as a text block that was written 10-15 years ago might be well and truly out of date by now... EMsmile (talk) 00:13, 19 August 2021 (UTC)

Update: I have now done the changes to Effects of climate change on oceans#Sea level rise that I had outlined above. The article Effects of climate change on oceans still needs further work but I'll discuss that on the article's own talk page. EMsmile (talk) 09:37, 9 February 2022 (UTC)

Should this article be in American or in British English?

I noticed that a mix of spellings are used in this article, e.g. centimeters (American) and centimetres (English). I tried to figure out what the dominant language version is so far for this article but am not sure. The consensus is to be consistent and to not change from one language version to the other without reason. What would you say is currently the dominant version for this article? If nobody minds, then I would suggest to set is as British English. No particular reason other than that many articles in the the WikiProject Climate Change are in British English, such as climate change. Let's reach consensus on either version and then stick with it? EMsmile (talk) 09:36, 9 May 2022 (UTC)

I agree to use British English Goneri Le Cozannet (talk) 08:36, 17 May 2022 (UTC)

Inconsistent units of length

The article is peppered with inconsistent units or length, including millimetres, centimetres, inches, feet, etc. This is really messy and makes it unnecessarily inconvenient to compare numbers. It really should be cleaned up by standardising on units, to present information in a scientific and literate way. E.g. mms (the SI unit) could be used throughout and inches could be appended in parentheses. 86.143.2.1 (talk) 08:36, 31 July 2021 (UTC)

I agree with you. I think it should be mostly centimeters and every now and again it also gets converted to inches. I don't think it's necessary to show the inches value each time (see also discussion at climate change article about Celcius and Fahrenheit...: https://en.wikipedia.org/wiki/Talk:Climate_change/Archive_90#Sentence_addition_to_the_lede_for_Americans_and_Fahrenheit EMsmile (talk) 09:32, 9 May 2022 (UTC)

Typically, IPCC reports use SI units. Imperial unites can be added for information between parenthesis if needed. Goneri Le Cozannet (talk) 08:40, 17 May 2022 (UTC)

Past Changes section

This section could be improved by explaining sea-level changes at different geological timescales and the causes since the mid-pliocene using, e.g., the sea level section of the Paleoclimate report of the 5th Assessment report . Goneri Le Cozannet (talk) 08:32, 17 May 2022 (UTC)

What do we even mean by "past changes"? I think this is unclear for a novice reader. "Past" could be thousands of years ago or it could be in the last 20 years. I presume we mean that time period that was not yet affected by greenhouse gas emissions? Maybe we change the section heading to "Sea level changes prior to anthropogenic influences" or "Changes prior to 1850" or "Changes in pre-historic times"? EMsmile (talk) 09:00, 17 May 2022 (UTC)

Having thought about it a bit more, I have moved that section to the end of the article, added links to other articles and changed the section title. There are other articles that deal with the sea level rise that was thousands of years ago: Past sea level, Sea level § Change, and Marine transgression (and others?). So I don't think we should add much content about it here. Is there anything in particular in that IPCC report that should be briefly mentioned? It would be good to provide that source at least once in this section. EMsmile (talk) 09:51, 17 May 2022 (UTC)

References

Proposed new ordering of the sections

I've just changed around the ordering of the sections. I think the order should be: what is it (current and predicted), what is causing it, how is it measured, what are the knock-on effects, how can we adapt to it, how could we prevent it or slow it down. While doing so, I felt that the section "what is it" was somehow lacking so I copied something from the lead. The "what is it" section should just state how much the sea level has risen so far since around 1850. We should make sure that we don't have content in the lead that is not in the main text (the lead is meant to be a summary of the article). EMsmile (talk) 10:30, 17 May 2022 (UTC)

We could consider the following article structure:

1. Past sea-level changes

1.1 Sea-level changes over geological timescales // short subsection linking to the main article on paleo sea-level changes

1.2 Contemporary sea-level changes

1.2.1 Measurements (satellite and tide gauge)

1.2.2 Observations

1.2.3 Regional variations

2. Causes of global sea-level rise

2.1 Ocean heating

2.2 Mountain glaciers

2.3 Greenland

2.4 Antarctica

2.5 Land water

2.6 Other contributions (the sea ice section seems not very convincing to me: the main effect of melting ice shelves would be accelerated Mass loss upstream in Antarctica, which would be much greater than 4cm - I would remove this)

3. Causes of regional variations

// is there any article in Wikipedia on this? If not, this could be a section here with the following items:

3.1 Non uniform ocean warming

3.2 Gravitational, Rotational and Deformational effects

4. Future sea-level rise

4.1 Projections for the 21st century (global and regional implications & effects (e.g., subsidence))

4.2 Long term sea-level rise

5. Impacts (formerly: effects)

I would support reorganizing as follows:

- 5.1 Coastal communities (incl. communities living along open coasts, delta & estuaries, and islands); refering to the Cross Chapter paper on Cities and settlement by the sea and the small island chapter

- 5.2 Economic impacts;

- 5.3 Ecosystems

6. Solutions

Short statement about synergies with mitigation

I would support organising as follows, refering to the Cross Chapter Box on Sea-level rise in AR6 :

- 6.1 Adaptation and mitigation

- 6.2 Adaptation options

- 6.3 Timing of adaptation

- 6.4 Governance of adaptation (incl. institutional regulation, adaptation funding,

- 6.5 Synergies and trade off with Sustainable development goals Goneri Le Cozannet (talk) 12:15, 17 May 2022 (UTC)

This looks like a reasonable outline to me. There is a key reference to add https://doi.org/10.1007/s10712-019-09525-z that gets at way more detail in terminology. I'd suggest mitigation being separate from adaptation (i.e., split 6.1 into two). Baylorfk (talk) 15:39, 26 May 2022 (UTC)

References

Thanks for this. I find it still a bit confusing to speak of "Contemporary sea-level changes". Is the baseline for that the year 1850? Or later? Also, I think the section on future sea level rise should be located directly after the section on the observed current/contemporary see level rise. I would still move the section "Sea-level changes over geological timescales" to the very end because the article is clearly about the more recent sea level rise so that information about the geological timescales should not take up prime position as the first thing that people see. EMsmile (talk) 11:09, 18 May 2022 (UTC)

Thank you.

In general we contextualize contemporary sea-level rise with sea level changes over geological timescales. This seems more logical to me, but there is no strict rule regarding how to present this. So I am fine with this.

Similarly, I find it difficult to present sea level projections before explaining the causes of observed sea level rise, but this might be because I am used to read always the same type of outlines in reports. Goneri Le Cozannet (talk) 17:09, 19 May 2022 (UTC)

I have removed the 'prevention' section, which was about ways to mitigate climate change and is out of the scope of this article. Goneri Le Cozannet (talk) 17:14, 19 May 2022 (UTC)

I see you've put the section back in and I've just renamed it to "Methods for slowing down sea level rise" with a reference to the AR6 WG2 Chapter 3. Thanks. EMsmile (talk) 14:13, 24 May 2022 (UTC)

Clarify that change is non-linear

If you zoom in on certain decades (like 1990-2010) observed changes are relatively linear (and there are oscillations with a period of a few years that make change harder to spot by eye). But zooming out, change is decidedly geometric since 1980s-era measurements started, and acceleration is both well-measured and reasonably well understood (e.g., where a majority of change comes from ice sheet melting, changes in albedo provide positive feedback).

The article should more clearly show the non-linear changes. Currently in a number of places it implies a linear progression and features data averaging annual changes over the past ~3 decades. We might find sources that clearly show that for a given scenario (say RCP 4.5 or 8.5) most of the SRL in the 21st century will come about in the last decade or two. (and may still be accelerating at that point). – SJ + 01:18, 4 July 2022 (UTC)

Section on prevention?

I think it would be good to have a section heading called "prevention". With most broad topics there are headings such as "components", "problems", "approaches", "policies", "costs" and also "prevention" etc. As a layperson I would look for "so how could sea level rise be prevented?". The sentence about that has now been moved to be inside of the adaptation section. But that's not where I would look for it in the TOC. Previously we had called it "Methods for slowing down sea level rise". I can see your point, User:Femkemilene, that that wasn't ideal (although I don't regard it as POV?). But perhaps a better solution could be found. That fact that it is NOT reversible might come to a shock to some but is an important piece of information. EMsmile (talk) 21:53, 21 June 2022 (UTC)

Can you give me a source that would support that? Some form of overview source about SLR that has mitigation separate from projections/adaptations. I've read quite a lot on the topic, and I don't think that's how sources cover it: they mention the most high-level (much/little mitigation), without going into details. Femke (talk) 16:36, 22 June 2022 (UTC)

I don't think any of the similar articles have such a structure either: tropical cyclones and climate change, climate change and gender, Climate change and children just three examples (the one counter-example climate change and poverty was just some pro-nuclear POV pushing, now replaced with excerpt).

Will be on wikibreak for a week. Femke (talk) 16:42, 22 June 2022 (UTC)

I've thought about this further and would like to suggest this: we rename the section to "Adaptation and prevention" or "Prevention and adaptation". In this case there could be some short sentences about preventing a faster rise and the fact that it's irreversible for thousands of years. I think this matches with the IPCC sixth report (Working Group II) which has a "Cross-Chapter Box SLR: Sea Level Rise" starting on page 3-125 which has the following subheadings: Current impacts of sea level rise, Projected risks to coastal communities, Infrastructure and ecosystems, and lastly "Solutions, opportunities and limits to adaptation". That section starts with "The ability to adapt to current coastal impacts, to cope with future coastal risks, and to prevent further acceleration of SLR beyond 2050 depends on immediate mitigation and adapt".

The section could also include a sentence along the lines of this news item from the Independent: Continued sea level rise ‘irreversible’ for centuries, says landmark UN climate report or this one from The Guardian We can’t stop rising sea levels, but we still have a chance to slow them down. or this one from National Geographic: Sea level will rise for centuries. We can control how much and how fast..

So far, the term "irreversible" appears only twice in the Wikipedia article but not very clearly: A study published in 2017 concluded that Greenland's peripheral glaciers and ice caps crossed an irreversible tipping point around 1997, and will continue to melt and Crossing such tipping points would mean that ice-sheet changes are potentially irreversible: a decrease to pre-industrial temperatures may not stabilize the ice sheet once the tipping point has been crossed. EMsmile (talk) 20:46, 22 June 2022 (UTC)

So in summary, I think information about reversible/irreversible and slowing SLR down is WP:DUE and should be visible in the TOC, hence my proposal to have a section heading called "Prevention and adaptation". EMsmile (talk) 20:46, 22 June 2022 (UTC)

Enjoy aour wikibreak. :-) EMsmile (talk) 20:46, 22 June 2022 (UTC)

I think you're right we don't talk sufficiently explicitly about mitigation. Our text (projections) is structured like: they said it was bad 15 years ago, they said it was worse 8 years ago, but it's actually superbad. I've tweaked the lead to emphasise SLR at different values of global warming instead, but it needs to be tweaked further. SLR at different mitigation levels belongs primarily in the projections section, but can be mentioned in the adaptation section as well.

I prefer to talk about irreversibility / tipping pionts in the causes section, as each cause has different threshold behaviour. Again, a mention in the adaptation section can't hurt. Femke (talk) 14:28, 2 July 2022 (UTC)

I think that's good, thanks for that. I think this kind of content (how mitigation affects sea level rise) should also become visible and accessible through the table of content. Some people might like to jump directly to that topic. Hence my suggestion above to rename the section to "Adaptation and prevention" or "Prevention and adaptation". Having just adaptation on its own as a section title seems too fatalistic to me. Note also, as I wrote above, the section heading in the IPCC report is "Solutions, opportunities and limits to adaptation". EMsmile (talk) 09:15, 4 July 2022 (UTC)

That IPCC subsection is almost completely about adaptation solutions, adaptation opportunities, and limits to adaptation, so I'm not sure why you believe this is an argument to talk about mitigation here. The adaptation section is not a logical place to put something about mitigation in.

I've been thinking about how to put mitigation in a subheading in the projections section, but I couldn't come up with a good structure there either. Splitting it in terms of short-term, 2100, post 2100 seems the most logical to me. If you split it into low-emissions future / high-emissions future you're going to separeta estimations from one institution too far apart. (F.i. you will have paragraphs separating RCP2.6 vs RCP8.5). Femke (talk) 15:56, 4 July 2022 (UTC)

Well, I looked at the IPCC report because you wrote "Can you give me a source that would support that?". The IPCC report cross-sector chapter on SLR seems to think adaptation and mitigation together; I found several sentences along those lines. Personally, I would also prefer to talk about mitigation in a separate section to adaptation (and make it visible in the TOC) but when my proposal to do so was reverted, I felt putting it together with the adaptation section might be a good compromise. Here are some statements from the IPCC report along those lines:

• The challenge can be addressed by mitigation of climate change and coastal adaptation.
• Risks from SLR are very likely to increase by one order of magnitude well before 2100 without adaptation and mitigation action as agreed by parties to the Paris Agreement (very high confidence).
• The ability to adapt to current coastal impacts, to cope with future coastal risks, and to prevent further acceleration of SLR beyond 2050 depends on immediate mitigation and adaptation actions (very high confidence).
• Reducing the acceleration of SLR beyond 2050 will only be achieved with fast and profound mitigation of climate change
• Large-scale relocation has immense cultural, political, social and economic costs, and equity implications, which can be reduced by fast implementation of climate mitigation and adaptation policies.'' EMsmile (talk) 09:34, 5 July 2022 (UTC)

Yes, that IPCC section mentions mitigation a few times, but it's about adaptation conditional on mitigation. Which is different from talking about adaptation + mitigation on the same level, which a subheading like yours would imply.

I've tweaked the lede to emphasise mitigation even more in the lede (in the projections paragraph). Femke (talk) 19:37, 7 July 2022 (UTC)

I think the lead reads now quite well, thanks. Much better than before. But if IPCC talk about adaptation being "conditional" on mitigation then why don't we explain that as well in our adaptation section? Also, I am surprised that the term "mitigation" appears only 4 times overall and is not wikilinked on any of those occasions. The only wikilink to climate change mitigation is behind the wording "cutting CO2 emissions" once in the text. Are we purposefully trying to avoid to use the word "mitigation"? Wouldn't it be important to familiarise readers with this term, or are you saying it should consistently be avoided and replaced with "cutting CO2 emissions" or with "emission scenarios"? Just wondering. Apart from that, the article climate change mitigation needs a lot of work itself. Hoping to help tackle that in the next few months sometime. EMsmile (talk) 08:53, 8 July 2022 (UTC)

We have one small paragraph about mitigation in adaptation now. I think one big omission is the concepts of limits to adaptation: with too little mitigation, it'll just be impossible to adapt in some cases. @Goneri Le Cozannet: may be able to help us here. (I'm not going to edit outside of my field until I'm recoverd).

About mitigation, I slightly dislike the word and find it difficult to put it in natural-sounding sentences. That may be my lack of wordsmithing ability. When introducing jargon, you always have to either explain (leading to more ugly sentences), or teach by incorporating it well into the prose so that people learn from context (requires large brain from editors). Femke (talk) 16:14, 8 July 2022 (UTC)

References

Suggestion to convert to long references style

I'd like to convert this article to long ref style to make it more consistent, easier to move content from one article to another, easier for newcomers. Also the long ref style works better when articles use excerpts from other articles. Does anyone object? I've just today made this conversion at ocean heat content, too. EMsmile (talk) 11:45, 20 October 2022 (UTC)

The long-style is already the default in the article. No need to post on talk to tidy up the single citations that's in a different style. Femke (talk) 16:13, 20 October 2022 (UTC)

OK, thanks. I've made the changes now. It was actually quite fast because many of the publications given under "sources" were actually not used/linked anymore. So perhaps left over from earlier versions (?). Unless I didn't look right but I am pretty sure I did it correctly. EMsmile (talk) 22:52, 20 October 2022 (UTC)

If I added them, I probably used them as 'general references', used to determine the structure and weight of sections. It's a common practise on nlwiki, but not on enwiki, and this is the first article I wrote after switching to enwiki. Happy to see them removed in that case too, as the article has been updated a lot since. Femke (alt) (talk) 11:28, 21 October 2022 (UTC)

Ah I see. Is that similar to the "Further reading" section which some English Wikipedia articles have? (I tend to be critical of "further reading" as it's often outdated, too long, or generally messy). EMsmile (talk) 11:44, 21 October 2022 (UTC)

No, further reading sections are about sources that aren't used. General references are sources that are used more significantly than inline references, informing tone, weight and structure. They are even allowed to replace inline cites for some statements, but that is not best practise on enwiki. Femke (alt) (talk) 11:48, 21 October 2022 (UTC)

Proposal to change the very first sentence

The very first sentence of the article is currently like this "Tide gauge measurements show that the current global sea level rise began at the start of the 20th century." I suggest to change it to either: "The current global sea level rise began at the start of the 20th century. This observation is based on tide gauge measurements." or put the info about "tide gauge" in brackets at the end of the sentence or even omit it. I think it's not a critical piece of information that it would need to be the very first thing that a layperson reader sees. Non experts won't know what a "tide gauge" even is (it wasn't even wikilinked until now). The details of the measurements can come a little later. It's also not a word that non-English native speakers would be very familiar with. EMsmile (talk) 08:49, 8 July 2022 (UTC)

I agree, and was planning on changing that. The evidence for SLR in that period comes from geological proxies as well as tide gauge anyway. I'm not sure whether the body supports the time frame (start of the 20th century). There are some complications with disentangling the SLR after the little ice age and due to global warming, but that can be a separate edit. Femke (talk) 16:01, 8 July 2022 (UTC)

Coming back to this discussion from July: I am just looking at this again while doing work on the effects of climate change on oceans article. It currently has a para on sea level rise plus an excerpt (first para of this article) and I am trying to figure out if that is OK or if I should use only the excerpt or no excerpt. I find the first sentence and first paragraph of the lead not very readable somehow. What's the verdict regarding those American units? Do we have to have them in the lead, or perhaps only in the main text in some strategic places but not everywhere? EMsmile (talk) 11:42, 21 October 2022 (UTC)

Maybe this could be a suitable first sentence: Since about 1900, the sea level has risen worldwide at an average rate of 1–2 mm/yr (the global average sea level was about 15–25 cm higher in 2018 compared to 1900).. This is the one I've just created at effects of climate change on oceans#Sea level rise. EMsmile (talk) 11:48, 21 October 2022 (UTC)

I think putting SLR in mm/yr gives the impression it's insignificant. This also duplicates information. I'd say something like: "Globally, sea levels are rising due to human-caused climate change" Femke (talk) 17:34, 21 October 2022 (UTC)

Yes, that's a good first sentence. Later in the lead we could use the mm/yr figure. Perhaps it sounds like a small change but it is what it is. Also, it's a useful figure when talking about how the pace of SLR is changing now. In the effects of climate change on oceans article we wrote it like this Since about 1900, the sea level has risen worldwide at an average rate of 1–2 mm/yr (the global average sea level was about 15–25 cm higher in 2018 compared to 1900). [...] The rise is due to the net flux of heat into the surface of the land and oceans. The pace of sea level rise is now increasing: The sea level rose by about 4 mm per year from 2006 to 2018. And directly after that we talk about why that is a problem for humans. I think this ought to be already in the first para of sea level rise, too. Here it only comes in the third paragraph. We could e.g. swap the second with the third paragraph. And I'd be inclined to take out some of the American units to increase readability. Would this be feasible? Perhaps leave them only in 2 places, once for the mm figure and once for the cm figure? At the moment, the unit conversion is in 8 places in the lead which makes for very cumbersome reading. EMsmile (talk) 23:24, 21 October 2022 (UTC)

There was a previous consensus not to convert mm into US units, as they use that unit too (I was told). Happy for less emphasis on numbers in the first paragraph.

Not interested in improving the prose quality of that article, but I've taken out the two sentences not supported by the source. I don't know if these sentences came from experts, or from you, but the source did not support all of the text preceding it. Within scientific literature, it's common to not cite everything. In that sense, the sourcing is often better on Wikipedia than in peer-reviewed literature. Femke (talk) 09:01, 22 October 2022 (UTC)

Ah, that's great that they also use mm in the US! That makes it a bit easier. And thanks for removing these two sentences This finding is based on many studies of coastal tide gauge records. The rise is due to the net flux of heat into the surface of the land and oceans. from the effects of climate change on oceans. They weren't added by me but are older and had somehow "survived" our recent review and improvement efforts of that article. EMsmile (talk) 09:47, 22 October 2022 (UTC)

I've changed the first sentence now to Globally, sea levels are now rising due to human-caused climate change, and this current global sea level rise (SLR) began at the start of the 20th century. (or is this too long, or should some key figures already be in the first sentence?). I had planned for more consensus to emerge before editing the lead but I see that User:InformationToKnowledge has dived in and has been bold so then I thought I might as well make this change, too, given that I first talked about it here on the talk page on 8 July. EMsmile (talk) 22:26, 26 October 2022 (UTC)

Thanks! What part of the body supports the current second half of the sentence? Can't find it easily. If unsupported, we could leave it out.

Have you ever done WP:REDEX? It's a great set of exercises to write shorter and clearer sentences without losing any information, by avoiding redundancy. Femke (alt) (talk) 11:37, 27 October 2022 (UTC)

The second part of the sentence is only there because it was there before "Tide gauge measurements show that the current global sea level rise began at the start of the 20th century." But thinking about it now, it needs to be changed because that 1900 figure is probably just a "definition thing" because we have the tide gauge measurements since then. Probably SLR was there before then as well. Maybe we could explain it like this (not in the first sentence but later) "Contemporary SLR is defined as the change in sea level relative to the reference point of the year 1900"? EMsmile (talk) 11:52, 27 October 2022 (UTC)

and thanks for the tip on WP:REDEX. Looks great, and I really need it! Most of us academics are probably suffering from "long & complicated sentence syndrome"! I do try to keep them shorter, also for the benefit of non-native English speakers or those who are translating English articles into other languages. So if REDEX can help me get better at it, that's great! EMsmile (talk) 11:52, 27 October 2022 (UTC)

References

Causes and timelines are in-scope

Contrary to User:Femke's reversion [[9]], causes and timeline are not "out of scope". Certainly, attributing cause to only climate change is a WP:NOV violation. Michaelmalak (talk) 18:12, 19 December 2022 (UTC)

Hi Michaelmalak, you might have overlooked the hatnote of this article which clearly states: "This article is about the current and projected rise in the world's average sea level associated with climate change. For sea level rise in general, see Marine transgression. Therefore your edits are out of scope of this article but could fit at Marine transgression. I agree with Femke's reversal of your edit (and had earlier reverted it something similar by another user myself). EMsmile (talk) 18:57, 19 December 2022 (UTC)

Correction: Femke did *not* revert any change of mine. I don't know who 74.71.129.103 is. Please do not accuse me of breaking Wikipedia etiquette of repeatedly submitting the same edit.

I did overlook the hatnote. It would seem, then, that other parts of this article are in violation of that hatnote. For example, "This is caused by both unsustainable extraction of groundwater", which is not related to climate change.

I propose that Marine transgression be merged into this article, and that this article cover all causes of sea level rise: anthropogenic climate change, non-anthropogenic climate change, anthropogenic non-climate-change and non-anthropogenic non-climate-change. Michaelmalak (talk) 19:34, 19 December 2022 (UTC)

There is an enormous body of literature on current SLR, so merging non-anthropogenic sea level variations in here would lead to a topic that is much too broad.

You're right however that the scope of this article is not easy to define definitely. I'd would follow the hatnote, but note other causes too, as long as they are in an appropriate location. F.i. note if there are natural variations of SLR on top of the anthropogenic signal. —Femke 🐦 (talk) 19:49, 19 December 2022 (UTC)

Sorry about that, I've corrected my earlier comment now to say that the IP address user who edit just before you was not you. EMsmile (talk) 19:51, 19 December 2022 (UTC)

Apart from that sentence about groundwater extraction (which mentions a related issue which is OK, I think) where else does the article deviate from its hatnote focus? EMsmile (talk) 19:51, 19 December 2022 (UTC)

It's indeed interesting that Marine transgression is rather short. I could image that adding a section about "changes in the geologic past" could perhaps be added at the end of the sea level rise article (and its scope be broadened), similar to how we have done it at ocean acidification and carbon dioxide in Earth's atmosphere: they both focus on the current trends but have a section on "geologic past" at the end. Or we could maybe change the article title to Current sea level rise. Or Sea level rise since 1900 (like retreat of glaciers since 1850). But I could also imagine that those editors who have worked on the sea level rise article for longer might not think it's a good idea. Could be an interesting discussion to have? (or maybe it was already discussed in the past, haven't looked through the talk page archive yet) [I wrote this before seeing Femke's 19:49 edit, it was written in parallel] EMsmile (talk) 19:51, 19 December 2022 (UTC)

The article was called current sea level rise before, with a separate future sea level rise article. It was merged as most parts of that article overlapped (causes, areas at risk). To me, current sea level rise feels like an unnatural way of describing what most people simply call sea level rise. —Femke 🐦 (talk) 19:57, 19 December 2022 (UTC)

Which is the Wikipedia article that contains non-anthropogenic sea level variations (i.e. those in the geologic past)? The one called Marine transgression is very short, so that can't be the main place where that content is located? EMsmile (talk) 10:04, 20 December 2022 (UTC)

Is the image in the lead ideal?

Global sea level change since 1992, which has risen 10.1 centimeters (3.98 inches).

I am wondering if the current lead image is all that ideal (edit: the image that was used in the lead until 9 Jan 22 is now shown in the right side as the first image of this section). Why do we need an animation/video here, what value does it add? I find it a bit distracting. If the animation is showing something important that I missed then perhaps this could be clarified in the caption. Also the graph starts at 1992. Wouldn't it be better to have one that starts much earlier, maybe starting 1901? Maybe this chart ("Historical sea level reconstruction and projections up to 2100") that is currently further down would be more suitable for the lead (or is it too complex?). EMsmile (talk) 10:51, 19 December 2022 (UTC)

References

EMsmile (talk) 10:51, 19 December 2022 (UTC)

Pre-1990s SLR was relatively slow, and the current graphic covers most of the SLR increase in detail showing more precise changes within each year. Yes, the history-and-projections graphic is too detailed and techy for a lead image. You may want to check for more possibilities at Category:Sea level rise at Commons, though most charts there seem to be outdated: —RCraig09 (talk) 17:53, 19 December 2022 (UTC)

If Pre-1990s rise was slow then this would be great to visualise in a graph: slow rise first, faster rise now. How about this image, it goes until 2021 (but also only starts at 1993)

NASA-Satellite-sea-level-rise-observations

. I don't understand with the current image what the animation is supposed to tell us. EMsmile (talk) 19:15, 19 December 2022 (UTC)

Or how about this one which starts at 1880 (Sea Level Change 1880 to 2015):

Sea Level Change 1880 to 2015

EMsmile (talk) 19:54, 19 December 2022 (UTC)

The image that we currently have in the lead (with the rotating Earth animation) has very even, symmetrical fluctuations, they look similar to the annual cycles of CO2 in the atmosphere, but I assume this is an artefact? The other two graphs that I have proposed here have more irregular fluctuations which to me are likely more accurate. Does anyone object to me replacing the existing image in the lead with one of the two that I have proposed here (see on the right)? EMsmile (talk) 10:07, 20 December 2022 (UTC)

It's not our place to judge to judge the NASA graphic less accurate. But of the two graphics you favor, I prefer the one with the longer timeframe. —RCraig09 (talk) 18:41, 20 December 2022 (UTC)

I don't understand what you meant with "It's not our place to judge the NASA graphic less accurate"? It was an honest question, trying to understand why those variations look so regular and whether these are regular annual variations, just like we have those annual variations in CO2 in the atmosphere due to the Northern hemisphere summer/winter fluctuations. Please excuse my ignorance, maybe it's a stupid question. Either way I find it surprising that that NASA graph looks so "regular" whereas the other two that I have put here look less regular (and hence more real to me). Perhaps someone knows the reason for this? - I would be happy with the second graphic ("Sea Level Change 1880 to 2015"). Will wait a few more days to see if anyone objects or has a better one. EMsmile (talk) 12:21, 21 December 2022 (UTC)

I've changed the image of the lead now as per the earlier discussion. EMsmile (talk) 09:57, 9 January 2023 (UTC)

Article length

@InformationToKnowledge: while I very much appreciate your updates and expansions, the article now stands at 12,771 words / 77k readable prose, which is about 4000 words longer than the ideal "maximum" (WP:TOOBIG). Would you be willing to condense the article as well as expand? For instance, the lead needs to be around 500 words, and should not contain unique information. Alternatively, we could split and have an article about projections. —Femke 🐦 (talk) 17:40, 8 January 2023 (UTC)

Well, I condensed what I could and while I didn't attempt the lead (yet), I think there's quite a substantial improvement already. Though, because I also tried doing the automated unit conversion everywhere, it had naturally added extra "words" and may have masked a lot of the condensions to prosesize tool. What do you think?

I would also appreciate it a lot if you could help provide guidance on my talk page about a semi-related matter.InformationToKnowledge (talk) 07:03, 9 January 2023 (UTC)

I agree with Femke that the article is getting a bit too long; I think moving some content into a sub-article would indeed be a good solution. I find the section on "Regional examples" doesn't gel really well as it goes into other related topics like the impacts and how people cope with sea level rise in various countries. Should it perhaps be moved into a sub-article? - (and I've commented on the semi-related matter on your talk page, InformationToKnowledge.) EMsmile (talk) 12:08, 9 January 2023 (UTC)

Thank you for leaving those comments!

And I would disagree here. I think we all understand that the split-off subsections (whether on projections or regional impacts) would inherently receive much less traffic than if they were part of the main article, and I don't think sacrifice is warranted here. I am biased for sure, but I think that after my recent condensing, the current range of projections achieves the following:

a) introduces our readers to IPCC projections and explains the assumptions they were based on.

b) gives an overview of the most notable dissenting estimates and their reasoning.

c) explains the post-2100 evolution of sea level rise in a way which I think is essential. When there is only year 2050-2100 figures on one side and year 4000-12000 figures on the other, it's easy to be at loss about the post-2100 rates, and so the 2150-2300 figures are crucial for helping to fill in this gap.

Likewise, I think that the regional sections are really, really important at explaining this issue. As valuable as it is to explain the range of SLR numbers, at the end of the day they are still numbers, and they can be quite abstract to people. To me, regional sections make the issue far more concrete, as (almost) no matter where a reader lives, they can now picture how the places they know well will be affected in a few decades. If anything, I would rather condense the preceding sections (Impacts, Ecosystems and Adaptation) a bit. I didn't touch them during the earlier revisions as the other sections were more problematic, but on second thoughts, there are quite a lot of rather vague and repeating sentences and phrasings there, which can be condensed without any real harm. I.e. the first four sentences of the "Impacts" section.

Current and future sea level rise is set to have a number of impacts, particularly on coastal systems. Such impacts include higher and more frequent high-tide and storm-surge flooding, increased coastal erosion, inhibition of primary production processes, more extensive coastal inundation, changes in surface water quality and groundwater characteristics. This is projected in turn to increase loss of property and coastal habitats, increased flood risk and potential loss of life, loss of non-monetary cultural resources and values, impacts on agriculture and aquaculture through decline in soil and water quality, and loss of tourism, recreation, and transportation functions. Many of these impacts are detrimental.

They are indeed! Nobody would have understood that they are detrimental if we didn't have that sentence there!

More than a few other examples like that, but I am not going to list them: I'll just condense those sections when I have the time on the weekend.

Finally, while I understand why those recommended word counts exist, I think it's one of those cases where an exception can be made. In the archived discussion on WikiProject:Countries, a point was made that country articles virtually always exceed recommended sizes as it is. I checked for myself, and that is indeed the case.

France: Prose text 133 kB (21112 words).

Mexico: Prose text 123 kB (19432 words).

South Korea: Prose text 98 kB (15845 words).

To my knowledge, nobody is planning to split off enough material from those and other country pages until they meet the 8k word/60 kB standard. Compared to them, the current 73 kB size of this article (which I can probably condense into 60s) is still lean, and I would argue that this topic is as important as that of the country articles, so it's reasonable to allow extra length if it would help to display relevant information where it would actually be seen. InformationToKnowledge (talk) 09:14, 10 January 2023 (UTC)

Your knowledge is wrong. Country article do not "virtually always exceed recommended sizes". They are prone to bloat, because people think everything should go on the main page and not subpages. However, the bloated ones are poor articles (see the ones you linked). There are country articles that meet Wikipedia guidelines, which have had their material written in an appropriate WP:SUMMARYSTYLE, and they are the good quality articles. CMD (talk) 09:51, 10 January 2023 (UTC)

In addition to CMD's comment, technical articles are recommended to be shorter per WP:CANYOUREADTHIS. This is to make sure its still digestible for the average reader. —Femke 🐦 (talk) 18:18, 11 January 2023 (UTC)

I agree. If the main climate change article can manage to stay within the recommendation (53 kB (8250 words)), then any sub-article on climate change should be able to manage as well. Femke: what's your suggestion for potential to move parts of it into a sub-article? You said "Alternatively, we could split and have an article about projections". That would be the content that is currently in the section "projections"? Or maybe just the sub-section "Post-21st-century sea level rise"? And I still think there is room for condensing in the section on "Regional examples" (if not moving that to a sub-section). EMsmile (talk) 08:36, 12 January 2023 (UTC)

After the second round of extensive condensation, I was able to shave off another 5 kB, and the article is now down to 11,367 words/68 kB prose text. Climate change article is certainly smaller that, though, as it is broader yet, in some ways, shallower, with smaller and less detailed sections on average. Now the question is what to sacrifice from this article if we want to make it even smaller. InformationToKnowledge (talk) 16:13, 13 January 2023 (UTC)

Nicely done :). There are quite a few examples of primary sources that I would start with, for instance: "On the other hand, a 2017 paper led by the University of Melbourne researcher Alexander Nauels presented consistently higher SLR estimates than the AR5 after combining the respective Shared Socioeconomic Pathways (successor to RCPs) with their extended ice sheet processes modelling. SSP1-2.6 (RCP 2.6 equivalent) had the median 52 cm (20+1⁄2 in) with a range of 34–75 cm (13+1⁄2–29+1⁄2 in), SSP2-4.5 the median of 75 cm (29+1⁄2 in) and a range of 47–113 cm (18+1⁄2–44+1⁄2 in) and the RCP 8.5 equivalent had a median of 132 cm (4 ft 4 in) and a range of 95–189 cm (37+1⁄2–74+1⁄2 in). The upper end of that estimate would mean rapid sea level rise of up to 19 mm (3⁄4 in) per year by the end of the century"

In general, the text of Wikipedia should mainly consist of things that are in WP:Wikivoice. We don't report on papers, but we state facts as much as possible, using assessments and reviews. —Femke 🐦 (talk) 17:26, 13 January 2023 (UTC)

11,139 words now. I attempted to simplify that particular passage rather than to remove it entirely, as I still think it has sufficient notability to stay in some form.

If anything, I would agree with EMsmile that there's an opportunity to trim (but not remove!) the regional sections I added - at least the first two on Africa and Asia, which are currently disproportionately larger than the rest. However, I would not do that without migrating such detail to the corresponding regional/continental climate change pages. Sadly, they are in a considerably worse state than this page, so cleaning them up would be a prerequisite for that. InformationToKnowledge (talk) 08:30, 14 January 2023 (UTC)

Do you mean: move some of that content to climate change in Africa and to which other article? This might work (although the "climate change in Africa" article has rather low pageviews). EMsmile (talk) 16:52, 15 January 2023 (UTC)

Well, while it felt good to transpose the table on change in African floodplains & the list of Roman ruins/other coastal landmarks and Ramsar wetlands from AR6 to the article, I suspect that to an average person reading this page, it's just not very meaningful, and this information would be more useful to the people who would read climate change in Africa. In fact, a lot of the Ramsar/landmark articles are either stubs or outright redlinks, so they provide relatively little information to a general reader of this page. If anything, there's probably more of a chance that editors already following an article on Africa would be motivated to create/expand those articles after seeing them there. The issue is how to work these impacts of sea level rise into the canvas of that (already reasonably lengthy) article.

With the "Asia" section, the table on Bangladesh districts would almost certainly look better in climate change in Bangladesh. Some of the more complex details about economic impacts of sea level could probably be moved to a page on Climate change in Asia...except that it doesn't exist: there's only a redirect to the short climate section of Asia article. Recreating that (and the various issues in the "climate change in Africa" article) would most likely have to take precedence before this page can be condensed further. InformationToKnowledge (talk) 06:46, 18 January 2023 (UTC)