Talk:Thwaites Glacier/GA1

GA Review

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Reviewer: Mike Christie (talk · contribs) 23:03, 16 July 2023 (UTC)

I'll review this. Mike Christie (talk - contribs - library) 23:03, 16 July 2023 (UTC)

Looking at sources first:

• What makes geographic.org a reliable source? It appears they're republishing National Geospatial-Intelligence Agency data, which itself is reliable, but the website is run by Information Technology Associates per the copyright notice, which is a private company. Is there evidence that geographic.org is treated as reliable by other sources? Or could we get this data directly from the agency?
• FN 34 is a broken link, which means I can't determine reliability. This is the link. Is it possible to find an archived copy of the link?
• The link to Eos in FN 36 goes to the wrong article.
• What makes climatetippingpoints.info a reliable source? It appears to be a blog. Is the author a subject matter expert?

-- Mike Christie (talk - contribs - library) 11:10, 17 July 2023 (UTC)

Thanks for doing this review!

• Looking more closely, both of those links essentially duplicate GNIS and ITGC citations which are already present. Removed.
• I did find an archived copy, but I really wasn't happy with that source. I had to do more searching and rewrite those sections considerably in the light of information found in more reliable sources.
• Added a quote to Eos reference to clarify that it is the right citation both times it's used in the article.

  Sorry, I wasn't clear. I fixed the issue I was referring to in this edit -- the link was going to the Greek goddess of dawn. Mike Christie (talk - contribs - library) 22:12, 19 July 2023 (UTC)

• Adam Armstrong McKay is a climate scientist and the lead author of the Science paper cited in the preceding citation. That paper is currently paywalled, and the paywall won't be lifted until September (since Science adopted rules making all articles OA 12 months after the initial publication), so the author's blog on his own work is the most convenient way of citing key figures from that paper. (Not to mention that the author's comments are meant to be easier to understand than the formal language of the paper itself.)

InformationToKnowledge (talk) 12:20, 19 July 2023 (UTC)

More comments:

• I think some editing is needed to comply with WP:LEAD, which requires that the lead be a summary of the body -- that is, everything in the lead is also in the body. The basic geographic information about the location of the glacier is only in the lead at the moment. Just changing the first section's title to "Glacier location and features" and adding the basic information there would probably be enough.
• FYI, it's not necessary to add citations in the lead. It's fine to do so if you want to (and some editors do it) but it's not required because everything in the lead has to be in the body too, and should be cited there.
• The sentence starting "Other Antarctic features ..." seems a bit off-topic.
• The research history you cover starts in 2001. There were plenty of papers about the glacier before then; of course there's no requirement to recount the entire research history related to the glacier, only the current state of research, but have you looked through these older papers to see if there's anything relevant? Good article status only requires broad coverage, not comprehensive coverage, so it's probably OK to stick with the more recent papers, but I thought I'd ask. I'll look through sources I have on hand too and see if I can find anything interesting.

I'm going to pause there and put this review on hold to let you respond to the above points, and will pick up again once those are settled. Mike Christie (talk - contribs - library) 16:21, 17 July 2023 (UTC)

• Done.
• Well, this citation style what I have seen on every other climate change-related article I edited, so I followed it as well.

  It's fine; just wanted to make sure you were aware of the option. Mike Christie (talk - contribs - library) 22:37, 19 July 2023 (UTC)

• Moved to UW-Madison's page.
• Well, some of those papers (i.e. Mercer and Hughes papers from circa 1970s) are already mentioned in the previous sections, such as "Importance". My intention was that "Research" would focus specifically on the studies which had taken place after it became accepted that the glacier is highly vulnerable (since that is essentially the only reason anyone writes about it today) but I suppose this section title might be too vague for that. Perhaps another title would fit more? I.e. "Research into glacier retreat"? "Study of glacier's vulnerabilities"? Something like that?

  I think it's OK as it stands -- so long as you're aware of the research that's been done and don't think anything more needs to be mentioned. I can certainly understand that research only sped up when the importance of the glacier was recognized. Mike Christie (talk - contribs - library) 22:37, 19 July 2023 (UTC)

InformationToKnowledge (talk) 12:36, 19 July 2023 (UTC)

Have struck everything above, and left a couple of notes. I'll continue with the review either tonight or tomorrow. Mike Christie (talk - contribs - library) 22:37, 19 July 2023 (UTC)

Second pass

Reading through again. I'm copyediting a bit as I go; please revert if I screw anything up.

• "This immense size means that the repeated ice calving events at the glacier's marine terminus - the point where grounding line is in contact with water": I don't follow this. I thought the shelf prevented calving at the glacier's terminus; calving happens at the edge of the shelf.
  • The ice shelf only covers the east of the glacier. The reference makes it clear those calving events occur in the west, enabled by the loss of the original ice tongue. Perhaps the sentence could be clarified to reflect this, but it might look awkward to mention the ice shelf and the ice tongue in passing right before explaining them properly.

    OK, but the point of the sentence is just the enormous mass that's being shed. Can we bypass the question the "marine terminus" raises in my mind and perhaps other readers' minds by making it just "This immense size means that when ice calves from the glacier, it sheds enormous mass"? A separate point: I don't think it's clear anywhere in the subsections of the "Location and features" section that the western side of the glacier calves at the grounding line and has no shelf. The image File:Miles_2020_Thwaites_tongue_shelf.png is unclear -- is this just the eastern half of the GL? I assumed the black area was open water implying the GL is not a calving front anywhere on this image, at least. Mike Christie (talk - contribs - library) 18:24, 31 July 2023 (UTC)

    After I found another image and rewrote some of the section, I think that this point is now much clearer than it was before, and there is no need to remove the mention of a marine terminus. InformationToKnowledge (talk) 10:35, 1 August 2023 (UTC)

    That's a helpful map, and I agree we don't need to drop mention of the marine terminus now. Mike Christie (talk - contribs - library) 12:30, 4 August 2023 (UTC)

• The image in the infobox says "Thwaites glacier", but since it shows open water, surely that's the ice shelf?
  • See above. The source, NASA, captions this image "Thwaites Glacier", so we are only following their lead.

    OK; I'll hold off on striking this until the point above is dealt with. Mike Christie (talk - contribs - library) 18:24, 31 July 2023 (UTC)

• Suggest explaining the acronyms in the ice tongue image, or else removing them from the image.
  • Done.
• The explanations of the various tongues is confusing. Here's what I think I understand:
  • Thwaites Glacier Tongue and Western Glacier Tongue refer to the same thing. This was a floating part of the glacier, which was present in 1947, had grown by 1967, and completely disappeared in 2016.
  • Thwaites Iceberg Tongue refers to a group of icebergs aground in the Amundsen sea, separated from the Thwaites Glacier Tongue, initially by 3 miles, but further away now. These were created by calving from the Thwaites Glacier Tongue, prior to (and after?) 1967.
  • Thwaites Glacier Ice Tongue is another group of icebergs broken away from the Thwaites Glacier Tongue, with the calving completed by 2012, and presumably having started after 1967 since the icebergs broken off before that formed the Thwaites Iceberg Tongue, not the Thwaites Glacier Ice Tongue.
    If this is all correct I have a few questions/suggestions.
  • If the grounding line is the dividing line between the glacier and the shelf, why is a floating section of ice referred to as part of the glacier? E.g. "was a narrow, floating part of the glacier".
    • Not quite: grounding line is the point at which glacier's weight is floating in the water, rather than being supported by the bedrock. See this article for an explanation. This means that the part of the glacier past the grounding line (such as the ice tongue) is not directly relevant to sea level rise, as its weight is already in water. However, it still helps to buttress ice on bedrock, much like the ice shelves: the difference between the two is that the ice shelves do not have an unbroken ice connection to the glacier itself.

      Struck. I wasn't aware of the difference in definition between "ice tongue" and "ice sheet", and that's not the fault of this article. If I can think of a way to clarify this without cluttering the article with too many inline definitions I will suggest it. Mike Christie (talk - contribs - library) 18:40, 31 July 2023 (UTC)

  • The image caption says "Thwaites Ice Tongue"; I think this should be "Thwaites Glacier Ice Tongue" if I have the definitions above correct.

    I think this is still an issue? Mike Christie (talk - contribs - library) 18:40, 31 July 2023 (UTC)

    It actually seems like I made a larger mistake by reading too much into the reference explaining the 2023 paper with the algorithm (formerly phys.org, now ESA). It appears it was the only one which really used that wording ("Thwaites Glacier Ice Tongue") and even then, it was largely interchangeable. Other references still use the same name even when describing how it broke up. I decided to remove this phrasing and changed section title to "Post-2010 break-up", since all recent sources agree on that. InformationToKnowledge (talk) 10:55, 1 August 2023 (UTC)

  • A map showing all of these together, along with some of the landmarks mentioned in the text such as Bear Peninsula, would be very helpful. I've spent some time trying to correlate visually the different images, particularly File:Miles 2020 Thwaites tongue shelf.png, File:Wolovick2023 Thwaites flows.jpeg, and File:Dotto 2022 PIB meltwater.png, and it's hard to do -- they don't overlap exactly, they're at different scales, they don't clearly delineate glacier and sea boundaries, and one uses different notation for latitude and longitude and has a different orientation. A single map that gives a simple geographic overview would help. I wouldn't fail this nomination if you can't come up with such a map, since the information is here, but it would really help readability and I think would be a must if you want to take this to featured level.
    • I understand your point about the maps, but scientific figures tend to be like that more often than not. I'll see if I can find something better, but I'm not hopeful.

      OK. I won't strike this but as I say I wouldn't require this for GA, and like you I'm not hopeful. Mike Christie (talk - contribs - library) 18:40, 31 July 2023 (UTC)

      I was able to find a satellite photo now. It's not perfect (it appears "flipped", since it has east on the left and west on the right) but it is a much better explanation of ice shelf vs. ice tongue and where the grounding line is, than anything else available, particularly in conjunction with the Miles 2020 graphic. InformationToKnowledge (talk) 10:59, 1 August 2023 (UTC)

• "In 2023, scientists from University of Bristol and University of Leeds had repurposed a machine learning algorithm normally used in microbiology to identify crevasses in Thwaites Glacier Ice Tongue and project how they may affect its stability." This sounds interesting but you're not citing any conclusions from this, and presumably this is too recent to have commentary from other scientists or for its predictions to be validated, so is it worth including?
  • Well, it's cutting-edge research. For now, they have simply demonstrated they can do it: more specific findings are bound to be in future papers 2-3 years away. We could remove this reference until the time they produce follow-up research, but this article isn't really suffering from the lack of space, so I don't think it's necessary.

    In addition, I looked at it again and found some notable details about the recent ice tongue retreat rates. Included them as well. InformationToKnowledge (talk) 11:01, 1 August 2023 (UTC)

• "seminal 1968 paper": cut "seminal", unless we have sources using similar language this is a bit dramatic.
  • The NASA source doesn't use this exact word, but it certainly seems to consider that paper as the root of current research into the glacier. Considering that it was published only a year after the glacier got its name in the first place, it's unlikely there was anything earlier. I am not firmly invested in that wording, but I am not yet convinced it is unjustified.
• "Overhead view of Thwaites Glacier, with arrows marking the warm water currents leading to its demise." Suggest "projected demise"; it's not dead yet ....
  • Done.
• "its strongly negative mass balance": is there numerical data for the mass balance that could be quoted?
  • Yes, the source mentioned mass balance. Added.

    Also found an update on more recent mass balance when going back to the ITGC reference. InformationToKnowledge (talk) 11:02, 1 August 2023 (UTC)

• "which was later attributed to the activity of subglacial lakes upstream of Thwaites": as written this implies these lakes were not under Thwaites, but that seems unlikely. Should this be "the activity of subglacial lakes upglacier"?
  • That was a typo: what [FN 60] said was "Finally, in the Amundsen Sea Embayment, West Antarctica, subglacial lake drainage events upstream on Thwaites Glacier may have caused a minor speedup of the glacier near the grounding line in 2013" - i.e. upstream of the Amundsen Sea and the grounding line. Corrected. This should also answer your reference spot check concerns.
• "with an estimated cost of $50 million across the entire research period": what's the intended research period?
  • The previous sentence says 5 years. The sources are a little contradictory on when it began: some say it was founded in 2017, but others that the research did not start until 2018. It's probably the latter, since we are now in 2023, and it doesn't seem like the project has been wound down yet. Then again, perhaps it will get extended anyway, or already has been. This is why I would rather not elaborate even more.

    Fair enough. Mike Christie (talk - contribs - library) 18:45, 31 July 2023 (UTC)

• "increasing its annual contribution to sea level rise from 4% to 5% in the near term": this is precise but a bit abstract. Can we phrase this in terms of sea level rise -- e.g. since sea level rise is 4 mm/year, if I remember correctly, this means Thwaites contribution to sea level rise will increase from 1.6 mm/decade to 2 mm/decade in the near term. We'd have to source the current sea level rise rate to do this, but I think it would make the effect more concrete for the reader.
  • I'll have to search more carefully for any figures like that. Found this source, but it is from 2018 and doesn't seem to explicitly consider near-term ice shelf loss. (Still seems worthy of inclusion, though.)

    Striking; I don't think I can fairly hold up GA status for this, since it's correct as written, but it would be nice to make it easier to grasp if you run across a source that allows you to do so. Mike Christie (talk - contribs - library) 18:47, 31 July 2023 (UTC)

  Well, I couldn't find a source saying this specifically, but I did add a note from ITGC that the 14-year sea level rise from Thwaites alone was 2.07 mm, which is probably the next best thing. Plus, I added the 30-year and 100-year projections from the 2018 paper above. InformationToKnowledge (talk) 11:09, 1 August 2023 (UTC)

• The three sentences starting "The lead of ITGC" seem a bit repetitive -- they say "This glaciologist said it was daunting; these ones said it worrisome, this one said it was going to happen soon. I think it would be better to make this more concise -- perhaps something like "These results have been described by glaciologists as "daunting" and "worrisome", Erin Pettit, an ITGC, said that Thwaites, along with the rest of the West Antarctic Ice Sheet ..." The details of exactly which glaciologists said the first two things can be left to the citations, I think; the point being made gets a bit diluted if we add that information to the sentence.
  • User:EMsmile has already edited that passage (and other parts of the article) a bit. Not sure if you already consider those changes sufficient.

    Still seems repetitive to me. Why do we need three separate statements about the gravity of the situation, all from the last couple of years? It's daunting, it's worrisome, it's going to happen soon. Citing all three sources isn't the problem, it's that the reader sees the same information three times, rather than one statement. Mike Christie (talk - contribs - library) 18:51, 31 July 2023 (UTC)

  Condensed. Instead of this, I used the 2014 paper cited later in the article a bit more, to clarify what the "rapid collapse" of the glacier means in scientific terms. InformationToKnowledge (talk) 11:10, 1 August 2023 (UTC)

• "after the warming passed 1 °C (1.8 °F) in recent years": it's best to avoid language like "recent" because it gets out of date. Can we make this "since <year>"?
  • Changed to "early 21st century".
• "volume of ice equivalent to 40 cm (15+1⁄2 in), rather than the 65 cm (25+1⁄2 in) contained in the full glacier": what do these measurements refer to? Obviously not the volume of ice in the glacier.
  • Clarified.

I'll look at the image licensing next and then do some spotchecks on the sources. Mike Christie (talk - contribs - library) 14:29, 21 July 2023 (UTC)

No image issues. Will do spotchecks next. Mike Christie (talk - contribs - library) 15:42, 21 July 2023 (UTC)

Spotchecks. Footnote numbers refer to this version.

• FN 21 cites "This is more than twice as large as all of the sea level rise which occurred between 1901 and 2018 (estimated at 15–25 cm (6–10 in)), though only a fraction of the total sea level rise which would be seen in the future, particularly under high warming." I can't find this in the source. I tried searching for 2018 and got nowhere, and I also couldn't find Thwaites. Assuming that the numbers are sourced, are you drawing this comparison yourself, or is the comparison made in the sources? If so I think this might be edging into synthesis of the sources -- see WP:SYNTH for the relevant policy.
  • Turns out I linked to the older IPCC report, so the figure wasn't there. Corrected. But yes, it's true that this comparison wasn't explicitly drawn in either source. I don't think it's remotely as egregious as the examples on WP:SYNTH page, but if you think it still needs to be removed, then I will do so.

    I think I'm OK on the SYNTH issue, and I see the total 1901-208 number in the source, but where does the future rise number come from? If it's from another page in the same source I would just add that to the citation. Mike Christie (talk - contribs - library) 19:01, 31 July 2023 (UTC)

Yes, page 21 shows just how much larger the future sea level rise can get. Noted that page number now. InformationToKnowledge (talk) 11:12, 1 August 2023 (UTC)

• FN 11 cites "If confirmed, this would mean that the melting of Thwaites Glacier can be expected to accelerate at a similar rate for the next century, regardless of whether ocean temperature keeps going up, or stops increasing at all." Verified.
• FNs 60 & 61 cite "In early 2013, a minor speedup of ice flow near the glacier grounding line was detected, which was later attributed to the activity of subglacial lakes upstream of Thwaites." I can see the second half of this in FN 61, but I can't find the relevant bit in FN 60 to support the first half -- can you point me at the right page?

-- Mike Christie (talk - contribs - library) 22:21, 21 July 2023 (UTC)

Alright, concerns about the images are a bit thorny, but I have addressed the rest.

InformationToKnowledge (talk) 19:16, 30 July 2023 (UTC)

Everything has now been addressed; passing. Congratulations! Mike Christie (talk - contribs - library) 12:42, 4 August 2023 (UTC)

Excellent! So excited to have the first GA under my belt! InformationToKnowledge (talk) 16:10, 4 August 2023 (UTC)