Talk:4.2-kiloyear event

Naming of the article
I find the title "4.2 kiloyear event" rather odd. It seems that in the literature it is more commonly called the "Holocene Climate Change". I find 1900+ hits for HCC and not a single one for "4.2 kiloyear event". I would not mind seeing it changed. The other point is that "Holocene Climate Change" more accurately describes what this is about. --AnnekeBart (talk) 21:21, 24 March 2011 (UTC)


 * I don't find any evidence in literature for the name "Holocene Climate Change". Remember, the Holocene is a fairly long period, and there have been a number of abrupt climatic changes ("events"), not only this one. So actually the name "Holocene Climate Change" would be pretty much ambiguous.
 * "4.2 ka event" (or variants) is actually commonly used name for this event, see for a recent example. --bender235 (talk) 23:20, 24 March 2011 (UTC)


 * "Holocene Climate Change" is used, , and in many more books and articles See Google Book Search. But I see your point that the term refers to several changes that took place over a long period of time. The 4200 BP event being one of the last ones. I retract my suggestion :-). Thanks for the feedback. --AnnekeBart (talk) 02:19, 25 March 2011 (UTC)


 * As far as I can see, "Holocene Climate Change" refers to the broad climate change from Pleistocene to Holocene, not a specific event within the Holocene period. --bender235 (talk) 02:53, 25 March 2011 (UTC)


 * I agree with you. Still think the terminology is odd. Will it be called the 4.3 kiloyear BP event 100 years from now? But that is not our problem :-) You mentioned it's called the 4.2 KY BP event in the literature, so that's our only choice for now. --AnnekeBart (talk) 13:10, 25 March 2011 (UTC)


 * Before Present means 1950. It probably still will in 2100. --bender235 (talk) 14:14, 25 March 2011 (UTC)


 * Ah, I'm being too literal I see. Thanks. --AnnekeBart (talk) 16:09, 25 March 2011 (UTC)
 * Before continuing to irritate people with ambiguous jargons, please name this in our standard, correct, normal, and unambiguous calender date of 2.25 ka cal BC, or, because it is not as narrow as suggested by this date, "the middle of the 23rd century BC". Thank you.2003:DD:F19:5A2B:89E1:2FBD:BED6:ECB8 (talk) 05:42, 24 October 2018 (UTC)
 * Further, regarding the Greenland temperature diagram, the assessment is correct, however, there is no "THE", but many more ice cores with around six interpretations, each of which differing somewhat against the others.2003:DD:F19:5A2B:89E1:2FBD:BED6:ECB8 (talk) 05:42, 24 October 2018 (UTC)

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The global map
The global map taken from Wang et al. (2016) paper is wrongly described. The error was made in the paper itself. The caption both in the paper and in Wikipedia says "The hatched areas were affected by drought or dust storms, and the dotted areas by wet conditions or flooding.". However, it is obvious that the areas of the greatest droughts in this period of time such as Egypt or Akkadian Empire (in Mesopotamia) are marked wrongly as flood areas. Also the very paper states that "In China, records from mountain glaciers and lacustrine sediments document the occurrence of drought in the north and flooding in the south at around the same time" which is reverse of what is shown on the map, as described. Friendly Neighbour (talk) 20:35, 23 November 2019 (UTC)
 * You're probably right! It would be nice to have another reference though (another map?) in order to back-up the change in caption... पाटलिपुत्र Pat   (talk) 20:46, 23 November 2019 (UTC)


 * I provided it on the Talk page of the 4.2event article. Friendly Neighbour (talk) 19:19, 30 November 2019 (UTC)
 * ? Can you give a link? पाटलिपुत्र Pat   (talk) 19:23, 30 November 2019 (UTC)
 * I did but than I screwed up. Here it is:
 * https://ars.els-cdn.com/content/image/1-s2.0-S027737911731003X-gr1.jpg
 * It is a direct link to Figure 1 of a paper which is beyond the paywall (I have access to it). The paper is Railsback L.B. et al., 2018, The timing, two-pulsed nature, and variable climatic expression of the 4.2 ka event: A review and new high-resolution stalagmite data from Namibia, Quat. Sci. Rev., 185, 78-90, https://doi.org/10.1016/j.quascirev.2018.02.015
 * The map is not so beautiful as the one we use (just red and blue dots for dry and wet anomalies) but it everywhere it has the dots they show the inverse of what "or" map does.
 * Friendly Neighbour (talk) 19:26, 30 November 2019 (UTC)
 * Thanks! All of this makes sense, and I'm glad you could find a good source to back up your remark! Since I'm the one who initially added the source and the map, I'm OK if you remove the current reference and rework the caption with your set of references. Based on that, I will add a note on the map at Commons reflecting what we have said. Thank you for your vigilance! पाटलिपुत्र Pat   (talk) 19:45, 30 November 2019 (UTC)
 * I am not sure how to do that. It would be dimple to replace "hatched" and "dotted" but we need to explain this. Should a second sentence be added, stating that the original caption had the markings reversed basing on (citations)? Correct? Friendly Neighbour (talk) 20:01, 30 November 2019 (UTC)
 * Another problem is that the name of the image file itself has the same error. Should we change that as well? Friendly Neighbour (talk) 20:05, 30 November 2019 (UTC)
 * OK, I'll do it, no problem. Thanks again! पाटलिपुत्र Pat   (talk) 20:14, 30 November 2019 (UTC)
 * Done, and thanks again. The name of the map will be corrected in the next few hours. पाटलिपुत्र Pat   (talk) 20:27, 30 November 2019 (UTC)

GISP2 Greenland temperature reconstruction
There has been a brief back and forth over this graph in the last couple of days. Could I remind you of Bold-Revert-Discuss -- so instead of replacing and re-removing it with only Edit summaries as explanation, perhaps we could work out here what the issues are and seek consensus. FrankP (talk) 20:00, 16 December 2019 (UTC)


 * My explanation in the original edit was clear: "Remove Greenland Gisp2 ice core graph because no citation is given for the GISP2 being related to the 4.2ka event. And GISP2 data is known to be problematic. https://www.carbonbrief.org/factcheck-what-greenland-ice-cores-say-about-past-and-present-climate-change".
 * The reverters explanation that he doesn't "believe" my citation is not a valid argument.
 * The inclusion of the graph is original research, the description "4.2-kiloyear event has no prominent signal in the Gisp2 ice core that has an onset at 4.2 ka BP." is not supported by any citation.
 * As my cite explains, the original GISP2 data is 20 years old, we now have better, newer, more comprehensive data available then GISP2. The original GISP2 data is mainly used today by those pushing an anti-climate change agenda to confuse people. PermanentE (talk) 22:55, 16 December 2019 (UTC)


 * Thanks PermanentE, I see what you're saying, haven't heard yet from the user who reverted, but let's not WP:RUSH. From what I see, the source you cite (CarbonBrief) is reliable, but then the inserted graph cites its datasource as NOAA, so that's good too. Also, the article you've quoted is warning about a graph which is not the same as the one we have here under discussion, if I've got this right. Even if both graphs might be based on GISP2 data. But then the GISP2 core seems (even according to your source) to be an appropriate source for data on the relevant time-period. Is this perhaps just a bit of a misunderstanding? Please correct me if I'm working on any wrong assumptions. FrankP (talk) 20:38, 17 December 2019 (UTC)


 * Your source for "GISP2 data is known to be problematic" is low quality; and in this case, wrong. People have mis-used it (as your source documents) but that's an entirely different matter William M. Connolley (talk) 20:41, 17 December 2019 (UTC)


 * Hi William M. Connolley, could you elaborate on that, I'm not sure I can disentangle the points you are making. FrankP (talk) 21:02, 17 December 2019 (UTC)
 * I'm puzzled by your puzzlement. Which bit didn't you understand? (a) Carbonbrief is not a good source for scientific info; (b) the problems noted in the CB article are irrelevant to this discussion; (c) something else William M. Connolley (talk) 15:20, 20 December 2019 (UTC)
 * Thanks for your reply. It's ok, I'm always puzzled by my puzzlement!
 * When you said "low quality", I was not sure if you meant in respect of this particular issue or generally as a scientific source -- you seem to have clarified that you meant it generally. I disagree, I think it is a good source (albeit journalistic rather than academic) for climate issues. But now that that is identified we can check into it further.
 * I think I agree with you that this CB article is not directly relevant, especially because (as I pointed out) the graph in question here is not the graph they are talking about there.
 * Yes there is something else. Not really about what you said, just something I want to say. I can't regard GISP2 data as problematic in itself -- data is just there, providing information, but in itself is neutral. It can only be interpretations of the data that might be problematic. FrankP (talk) 16:40, 20 December 2019 (UTC)
 * It is the same graph, or the same data. As the CB article explains it has been recreated several times as it travels across the web. The Wikipedia version seems to be taken from the 4th graph in the climate-sceptic blog linked by the CB article here https://foresight.org/some-historical-perspective/PermanentE (talk)
 * I've added a "citation needed" tag to the image caption referring to the factual claim contained therein. Is it possible someone could source an image using more recent ice-core data? FrankP (talk) 09:56, 20 December 2019 (UTC)
 * Not ending ... Correct is that the cooling/draught-event ca. 2200-1900 cal BC is not visible in all Greenland ice cores, in particular not in the Alley et al. (2003) GISP-2 version. It is, however, visible in my smoothing (15y) of the NGRIP_20y del18-O data, available from the University of Copenhagen web page. It is also suggested by the significant decline of the tree lines, documented, e.g., at the alpine Kauner-Glacier (Nussbaum et al. 2009). Both data are combined in the Holm Archaeoclimate of the Holocene graph, published in the wikipedia article "Holocene" (2021, NOT the one immediately appearing here!) - if not vandalized.HJHolm (talk) 08:59, 4 December 2021 (UTC)