Talk:Ice sheet

Antarctic warming

I have undone the addition on Antarctic warming by Phanly. This is for two reasons. Firstly, at present it does not fit into the page well. The Antarctic ice sheet includes the west antarctic ice sheet so a new section is confusing. This is a more general page on ice sheets and it is not at its current state useful to add this sort of detail. Phanly has added this same text to several articles, some where it fits better. Secondly the quality of the addition is poor. The citations/references have no style and need a large amount of work and all four of them (added multiple times and not joined) reference the same study by Eric Steig but in different ways including his biog and a blog. As good as this study is, it is no good throwing in 4 references to try to make it look like some sort of wide consensus when it is really one study. I am not against this addition in wikipedia. In fact I spent some time on the Antarctic Ice Sheet page improving the referencing that Phanly had added. Polargeo (talk) 08:58, 28 January 2009 (UTC)

Thanks Polargeo. I have followed your criticisms and inserted a simple single sentence and copied the Nature reference you greatly improved. Cheers dinghy (talk) 05:27, 30 January 2009 (UTC)

never know the secret

Changed link

I changed the link for "the Weichselian ice sheet". It was previously pointed at http://en.wikipedia.org/wiki/Wisconsin_glaciation which seemed to me to be a mistake. Bj norge (talk) 18:33, 13 June 2011 (UTC)

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how can the thickness of an ice shield be measured ?

(in some cases by drilling ;-)

here https://www.nature.com/articles/nclimate2161

footnote 9: repeat stereo satellite imagery

footnote 27 (1997) : satellite radar interferometry

what exactly is it ? How exact are the data obtained with these methods ?

I hope there is an expert ( m / f / d ) who can add a section to the article. thanks in advance ! --Präziser (talk) 05:57, 15 June 2022 (UTC)

That would indeed be good to add some information on that. You don't need to be an expert either, just have to know how to read the scientific literature on this. :-) I don't have time at the moment, otherwise I would do it. Perhaps there is information about it in the Antarctic ice sheet or Greenland ice sheet articles? Pinging User:InformationToKnowledge, perhaps they know this topic off hand. EMsmile (talk) 21:40, 20 December 2023 (UTC)

Overhaul (December 2023)

I've just reworked this article and have replaced a lot of the content with excerpts. That's because this is a fast moving topic (due to climate change...) and the bulk of the detail sits in the articles on Antarctic ice sheet and Greenland ice sheet. So I think excerpts are the ideal solution here for this article. It's really just an overview article about the two ice sheets on Earth. EMsmile (talk) 21:43, 20 December 2023 (UTC)

One thing to ponder over: should the content about geologic timescales be added to the main text (currently it's only in the lead)? Normally the lead is meant to summarise the content of the main text. EMsmile (talk) 21:43, 20 December 2023 (UTC)

I guess that since you have already excerpted the articles on the current ice sheets, providing excerpts from the articles about historical ice sheets would be reasonable.

As an aside: I see that there are now some contradictions between Greenland ice sheet after my recent edits and the excerpted section on GrIS from effects of climate change. The tricky part is that the latter is based on the 2019 SROCC, which wasn't really featured in the GrIS article at any point. Though the GrIS article now includes a lot of information from newer sources (information, which should be moved to the excerpt as well), I really need to think on how to work at least some of those references to SROCC into the article too, since it remains an important signpost in climate science.

Going back to directly double-check the accuracy of information cited to SROCC and even AR6 might be necessary: i.e. I have some doubts that "The Greenland ice sheet loss is mainly driven by melt from the top. Antarctic ice loss is driven by warm ocean water melting the outlet glaciers." is an accurate summary of what AR6 actually said, since two major papers on Greenland published 1-3 years before AR6 concluded that surface melt is responsible for no more than 33-51%, with outlet glaciers causing the rest. InformationToKnowledge (talk) 14:25, 21 December 2023 (UTC)

Regarding the geologic timescales I have now added two excerpts for that. Is "geologic timescales" the best wording? I've seen also "Ancient Earth" and "pre-history" but personally I think I like "geologic timescales" the best. Could also be convinced otherwise though.

Regarding the details from different reports: this would be useful/important to document and reconcile but I can imagine that it can be quite fiddly / detective work. Would be good to have additional people to help with that, maybe even experts in the field who have all that knowledge at their fingertips. EMsmile (talk) 10:38, 22 December 2023 (UTC)

Merges and reorganization (April 2024)

So, following another talk page discussion, I have first merged the article on marine ice sheet instability into the article called ice-sheet dynamics, and then I merged the material from that article here. After all, this article isn't too large and receives about 10X daily views than those two (~200 here vs. 10-20 for either of those), so all the truly valuable information should be present here. I have also done my best to clean up and reorganize this article after merge, but there are limits to what I could achieve today.

In particular, I suspect that more-or-less the entirety of "Subglacial processes" section is going to be impenetrable to most readers. I am sure it can be condensed a lot, but I cannot think of a way right now. Moreover, it now seems like a lot of the material in that section is not actually specific to ice sheets, and should probably be in one of the glacier-related articles instead? (Either Glacier itself, or, if that article is too large and cannot be condensed, a cleaned-up and probably renamed version of glacier mass balance. Unless there is a better third option.) I am really interested in what @Puddlesofmilk thinks about this. InformationToKnowledge (talk) 12:17, 6 April 2024 (UTC)

P.S. I removed the excerpt from Effects of climate change @EMsmile added earlier, as it really just said the same thing as the final paragraphs of excerpts from the three ice sheet articles, but in much less detail. I have also combined "Definition" (really just a single IPCC quote) with a subsequent section and expanded the part on ice sheets' carbon cycle into a separate section. InformationToKnowledge (talk) 12:21, 6 April 2024 (UTC)

Thanks for that. However, could we please re-insert the "definition" section? I think it's a nice, easily understandable way for lay person readers to find out what an ice sheet is. Starting the main text with "dynamics" is scary for lay persons. And it doesn't matter if the definition is already provided in the lead, as the lead is meant to be a summary of the article.

This is what the definition section looked like (yes, it was short, but is that really a problem? Perhaps there are other definitions or nuances that could be added later):

"=== Definition === An ice sheet is "an ice body originating on land that covers an area of continental size, generally defined as covering >50,000 km² , and that has formed over thousands of years through accumulation and compaction of snow"." EMsmile (talk) 20:39, 7 April 2024 (UTC)

I decided to write an expanded version and call it Overview. I think the result is pretty good, as it immediately makes our readers appreciate their scale.

I also took out a lot of the material I merged from ice-sheet dynamics earlier, as it didn't really have a whole lot to do with ice sheets specifically, so I just moved those paragraphs to Glacier instead. I really like how it went, because it seems like both articles are now fairly balanced in terms of size, scope and coverage. For the first time, I feel that this article would be a plausible GA candidate. We would probably want to get the articles it excerpts from to GA first, to be on the safe side, but otherwise, I don't think there would be many obstacles left. InformationToKnowledge (talk) 09:35, 10 April 2024 (UTC)

That's good, thanks. But do we really need this info so prominently and detailed early on in the article (seems Global North centric and like trivia to me)?: A notable 20th century example occurred early in World War II, when a Lockheed P-38 Lightning fighter plane crashed in Greenland. It was recovered in 1992, but by then, it had been buried under 268 ft (81+¹⁄₂ m) of ice which formed over those ~50 years, and was given the nickname Glacier Girl. EMsmile (talk) 09:03, 17 April 2024 (UTC)

If a Global South nation was ever so unlucky as to lose some of its people and aircraft over an ice sheet, I would have been very open to including that detail. As it is, this example is a great way of explaining how the ice sheets got so thick, and how this process is still occurring even in the recent decades, in terms which are immediately relatable. InformationToKnowledge (talk) 06:37, 18 April 2024 (UTC)

yes, maybe, but then it would be better to write it in more general terms. And this part in my opinion is trivia and doesn't belong: "and was given the nickname Glacier Girl" (the link to the other article could be made in a different way). Anyway, minor detail. EMsmile (talk) 07:53, 18 April 2024 (UTC)

I've changed it now a little bit to be like this: This process of ice sheet growth is still occurring nowadays, as can be clearly seen in an example that occurred in World War II. A Lockheed P-38 Lightning fighter plane crashed in Greenland in 1942. It was only recovered 50 years later. By then, it had been buried under 81 m (268 feet) of ice which had formed over that time period.

One thing I wonder: is or was that ice sheet growth linear? So if the plane had been buried for another 50 years would it then have been buried 162 m deep? And I am assuming the ice sheet growth is slowing down or reversing due to climate change? I think the example adds a bit of confusion - at least for me... Could we perhaps add a clarification on that? (the info is probably buried under the section on ice sheet dynamics but as the example of the plane is provided, I think it would help to spell it out better).

Maybe something like "ice sheet thickness growth is not linear and xxx". ?? EMsmile (talk) 08:05, 18 April 2024 (UTC)

References

Lead needs further work

You probably know this but just putting it here so that it's not forgotten: The lead needs more content now, post-merge, to summarise the new section on "dynamics". It's also too short. I think it should be 450 to 500 words long, and summarise each of the main sections as best as possible. EMsmile (talk) 20:44, 7 April 2024 (UTC)

I've now copied two paragraphs from the main text to the lead to explain a bit about the dynamics but this lead needs further work by someone who knows and understands ice sheets far better than I do. EMsmile (talk) 11:56, 20 June 2024 (UTC)