Talk:African humid period/GA1

GA Review

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Reviewer: Jens Lallensack (talk · contribs) 10:26, 10 March 2019 (UTC)

Will start reading soon, but I may take a while, as it is a long article! --Jens Lallensack (talk) 10:26, 10 March 2019 (UTC)

@Jens Lallensack: Thanks. Yes, this is the longest article I've ever written. Jo-Jo Eumerus (talk, contributions) 10:58, 10 March 2019 (UTC)

I'm sorry that I didn't get far yet. Here is the first bunch of points:

• It involved changes in Earth's orbit around the Sun, changes in vegetation and dust in the Sahara that altered the African monsoon, the disappearance of much of the Sahara desert which was replaced by grassy vegetation, trees and lakes and the settlement of the former desert by various animals and humans, who survived as hunter-gatherers. – You do not differentiate between causes and effects, why? I would have expected that both are treated separately.

  There is kind of a sorting with the cause being first and the effects second. First part is the ultimate cause, second part the feedback effects, third the actual changes and fourth their ramifications. Jo-Jo Eumerus (talk, contributions) 20:56, 16 March 2019 (UTC)

  Yes, but that sould be reflected in the wording, not only the order. I can only give suggestions, depends on you what you make of it. --Jens Lallensack (talk) 16:44, 24 March 2019 (UTC)

  Well, I do think that the "interesting" bits needs to stay in, as otherwise a reader unfamiliar with the topic has no idea that there is more to this than a technical article on a climate anomaly thousands of years ago. That necessarily restricts how much of it can be rewritten. Part of the point of a lead section is to hook a reader in to the article. Jo-Jo Eumerus (talk, contributions) 07:17, 25 March 2019 (UTC)

  I did not mean to remove something, I merely see a prose issue. What about "It was caused by changes in Earth's orbit around the Sun, and involved changes in vegetation …"? --Jens Lallensack (talk) 02:58, 25 April 2019 (UTC)

  Maybe I got it - check my edit to the lead section. Jo-Jo Eumerus (talk, contributions) 06:22, 25 April 2019 (UTC)

• who survived as hunter-gatherers. – why not simply "were hunter-gatherers"? Was the environment especially hostile that we need the word "survive"?

  Yeah, that wasn't intended. Changed. Jo-Jo Eumerus (talk, contributions) 20:56, 16 March 2019 (UTC)

• It has had profound effects on present-day Africa – as only culture stuff is listed, maybe specify with "present-day African culture"? As Ancient Egypt and the Golden Age myths impacted not only Africa, maybe you can even skip the "present-day Africa"?

  My concern with "present-day African culture" is that it's a bit too specific IMO, in terms of timespan. I think that Ancient Egypt should still be considered "Africa". As for the Golden Age myths ... I dunno how to formulate this. Jo-Jo Eumerus (talk, contributions) 20:56, 16 March 2019 (UTC)

• and had extensive dune fields, many lakes and rivers such – think you need a ";" here instead of the ",". With the latter, it reads like a listing, which misleads the reader.

  Remedied this. Jo-Jo Eumerus (talk, contributions) 20:56, 16 March 2019 (UTC)

• The African humid period commenced about 14,600–14,500 years ago at the end of Heinrich event 1 and concomitant to the Bølling-Allerød warming, rivers and lakes such as Lake Chad formed or expanded – not especially good with English grammar, but shouldn't this sentence start with "As the African humid period …", or alternatively "with rivers and lakes"?

  Does it work better with a ";" here than a ","? Jo-Jo Eumerus (talk, contributions) 20:56, 16 March 2019 (UTC)

• but the end of the African humid period came about 6,000–5,000 years ago during the Piora Oscillation cold period when the Sahara occupied its present position. – I would start a new sentence here.

  So done. Jo-Jo Eumerus (talk, contributions) 20:56, 16 March 2019 (UTC)

• such as these in the Cave of Swimmers – "such as those"?

  Done. Jo-Jo Eumerus (talk, contributions) 20:56, 16 March 2019 (UTC)

• which shifted the season during which Earth is closest to the Sun towards Northern Hemisphere summer during the early Holocene – a bit concoluted, lot of stuff put togehter here, not so easy to read. Why not moving the "during the early Holocene" to the sentence "The African humid period commenced …"? Would be more helpful there.

  Er, the Bølling-Allerød occurred during the late Pleistocene; the AHP was already set in when the Holocene started. Would it help to cut "Northern Hemisphere"? Jo-Jo Eumerus (talk, contributions) 20:56, 16 March 2019 (UTC)

• This was not enough to make the Sahara disappear – Suggest "This alone was not enough" for clarity. Otherwise one would assume that it means that the Sahara did not disappear completely.

  Added. Jo-Jo Eumerus (talk, contributions) 20:56, 16 March 2019 (UTC)

• Suggest to link or explain petroglyphs

  Linked. Jo-Jo Eumerus (talk, contributions) 20:56, 16 March 2019 (UTC)

• The terms "Léopoldvillien"[19] and Ogolien [fr] has been applied – have been

  Fixed. Jo-Jo Eumerus (talk, contributions) 20:56, 16 March 2019 (UTC)

• The terms "Léopoldvillien"[19] and Ogolien [fr] has been applied to the dry period in the last glacial maximum. – These terms are not mentioned again, so I wonder why they are relevant here? Reducing complexity would make it easier for readers.

  That section discusses the terminology, so indicating that it's called that way seems pertinent even if they aren't discussed again. Not entirely sure though. Jo-Jo Eumerus (talk, contributions) 20:56, 16 March 2019 (UTC)

• You use a mixture between American and British English.

  Sorry, but I don't know much about which is which in many circumstances. Jo-Jo Eumerus (talk, contributions) 20:56, 16 March 2019 (UTC)

• lake development in Tibesti and Jebel Marra mountains – do we need to have a "the" inserted here?

  Yes, added. Jo-Jo Eumerus (talk, contributions) 20:56, 16 March 2019 (UTC)

• In addition to drought, glaciers were active in the Bale and Semien Mountains of Ethiopia during the last glacial maximum – I'm confused about the "in addition". To what do drought + glaciers add up? Hostility? What does it want to tell us?

  Changed to "finally". Jo-Jo Eumerus (talk, contributions) 20:56, 16 March 2019 (UTC)

--Jens Lallensack (talk) 17:43, 16 March 2019 (UTC)

@Jens Lallensack:Well, it is a long article, as you said. This doesn't need to be done urgently. Jo-Jo Eumerus (talk, contributions) 20:56, 16 March 2019 (UTC)

• Due to the phenomenon called precession – this is wordy but does not explain anything; I also would not call it a "phenomenon", as it is more of a condition?

  I've shortened this; I am not sure if we want to explain what precession is in this article. Jo-Jo Eumerus (talk, contributions) 07:17, 25 March 2019 (UTC)

• This effect was strengthened by the increased summer insolation thus leading to a stronger monsoon that also reached farther north. – This, and the whole paragraph, is basically a repetition of what was already said. Suggest to merge it with the preceding paragraph.

  See, I was thinking the preceding paragraph was a description of how Earth's orbit changed, while this one is about the effects thereof. Jo-Jo Eumerus (talk, contributions) 07:17, 25 March 2019 (UTC)

• Obliquity and precession are among the foremost Milankovich cycles – these are not cycles, these are effects resulting in the cycles.

  Fixed. Jo-Jo Eumerus (talk, contributions) 07:17, 25 March 2019 (UTC)

• the ITCZ – I would really spell this out, makes it more accessible.

  Done, should it also be changed on every mention? Jo-Jo Eumerus (talk, contributions) 07:17, 25 March 2019 (UTC)

• correlate to changes – correlate "with"?

  Changed. Jo-Jo Eumerus (talk, contributions) 07:17, 25 March 2019 (UTC)

• Contrarily, northward transport of moisture during autumn and spring directed by throughs close to Northern Africa has also been proposed to explain the increased precipitation and its underestimation by climate models. – I don't get this

  Rewrote this a bit, does it work better now? Jo-Jo Eumerus (talk, contributions) 07:17, 25 March 2019 (UTC)

• increased water supply from montane region may have assisted – "regions"?

  Fixed. Jo-Jo Eumerus (talk, contributions) 07:17, 25 March 2019 (UTC)

• the atmospheric boundary layer. and – why the dot?

  Typo, removed. Jo-Jo Eumerus (talk, contributions) 07:17, 25 March 2019 (UTC)

• according to Kuhlmann et al. and Hoffman et al. – Maybe delete, as you do not name authorities in other sections?

  Sure, done. Jo-Jo Eumerus (talk, contributions) 07:17, 25 March 2019 (UTC)

• brown or yellow vegetation communities – what is this, can you link/explain?

  Oddly, neither the first source nor the source that source refers to explain this. I am guessing that it refers to the colour of the plants, though - not sure how to clarify. Jo-Jo Eumerus (talk, contributions) 07:17, 25 March 2019 (UTC)

• Pollen data often showing a dominance of grasses over humid tropics trees. – "show"?

  Fixed. Jo-Jo Eumerus (talk, contributions) 07:17, 25 March 2019 (UTC)

• Nevertheless, the Sahara did not become entirely homogeneous – too imprecise, maybe "climate of the Sahara"?

  Specified. Jo-Jo Eumerus (talk, contributions) 07:17, 25 March 2019 (UTC)

• its pollen in sediment core – "cores"

  Done. Jo-Jo Eumerus (talk, contributions) 07:17, 25 March 2019 (UTC)

• Earlier humid periods in the Sahara may have allowed species to cross the now-desert. – This means that the Holocene humid period did not?

  Not as far as we know; the thinking might be that all species exchanges happened in the earlier humid periods and that the Holocene AHP didn't add anything. Jo-Jo Eumerus (talk, contributions) 07:17, 25 March 2019 (UTC)

• A reduction in open grasslands caused by the African humid period may explain a population bottleneck in cheetahs at the start of the humid period – So they did not move northwards? I thought there was a lot of grass land during the period?

  This is going to be tough. This source believes that there may have been less grassland during the AHP. Other sources say it expanded. Seems like at first it may have shrunk; the source does not specify but I made a small change. Jo-Jo Eumerus (talk, contributions) 07:17, 25 March 2019 (UTC)

• both in Egypt and both feature archeological sites – "featuring"?

  Done, not sure if "feature" works as well however. Jo-Jo Eumerus (talk, contributions) 07:17, 25 March 2019 (UTC)

• the rivers were often connected between each other – "with each other"?

  "With" sounds a bit too strong for this context, as they weren't tributaries apparently. Jo-Jo Eumerus (talk, contributions) 07:17, 25 March 2019 (UTC)

• the rivers were often connected between each other through alluvial fans – Could you check if this should say "alluvial plains"?

  Checked, it says "alluvial fans". Jo-Jo Eumerus (talk, contributions) 07:17, 25 March 2019 (UTC)

• Some rivers discharging through Bay of Arguin – add "the"

  Done. Jo-Jo Eumerus (talk, contributions) 07:17, 25 March 2019 (UTC)

• and later pastoralists, – suggest "and, later, pastorialists"

  Done. Jo-Jo Eumerus (talk, contributions) 07:17, 25 March 2019 (UTC)

• as well as in Uan Tabu and Takarkori rock shelter both also in the Acacus Mountains – needs a comma?

  Done. Jo-Jo Eumerus (talk, contributions) 07:17, 25 March 2019 (UTC)

• hence it is also known as "aqualithic" – what is "it" referring to, the whole humid period? --Jens Lallensack (talk) 16:44, 24 March 2019 (UTC)

  Specified. Jo-Jo Eumerus (talk, contributions) 07:17, 25 March 2019 (UTC)

@Jens Lallensack:Thanks. Due to time constraints, I'll reply tomorrow. Jo-Jo Eumerus (talk, contributions) 21:14, 24 March 2019 (UTC)

@Jens Lallensack: OK, now actioned these issues. Jo-Jo Eumerus (talk, contributions) 07:17, 25 March 2019 (UTC)

@Jens Lallensack: CC'ing you about this conversation on the "implications for future climate change" section as William M. Connolley flagged a couple of problems there. I think I solved one of them but I am not so sure on the other. Jo-Jo Eumerus (talk, contributions) 16:27, 12 April 2019 (UTC)

I have currently no opinion here, I did not reach that section yet. --Jens Lallensack (talk) 02:58, 25 April 2019 (UTC)

• Waters from the Nile filled depressions like the Fayum Depression – dot missing

Done. Jo-Jo Eumerus (talk, contributions) 06:22, 25 April 2019 (UTC)

• relative to that of the White Nile – dot missing

Done. Jo-Jo Eumerus (talk, contributions) 06:22, 25 April 2019 (UTC)

• This overflowing large was filled with freshwater – what is a "large"?

Added. Jo-Jo Eumerus (talk, contributions) 06:22, 25 April 2019 (UTC)

• The African humid period ended about 6,000-5,000 years ago around 5,500 years before present and after a vegetation decline sand claimed the Sahara which became barren, accompanied by increases in dust export from the now-desert and from dried up lakes. – Long, complicated sentence that is hard to read.

I've cut that sentence up a bit. Jo-Jo Eumerus (talk, contributions) 06:22, 25 April 2019 (UTC)

• in a more protracted fashion, Distinct – full stop here?

Yes, done. Jo-Jo Eumerus (talk, contributions) 06:22, 25 April 2019 (UTC)

• two different insolation thresholds. – very technical language. Should be explained in language comprehensible to non-scientists.

Rewrote this a bit but it's not going to be easy to find an alternative to "insolation"/"irradiation". Jo-Jo Eumerus (talk, contributions) 06:22, 25 April 2019 (UTC)

• Increased autocorrelation – Again; translate into comprehensible language?

That's a tough one. Even I had to look up "autocorrelation" and it's apparently not something that's easily "translated" as each definition I've seen is just as technically worded; I've stripped it out for the time being. Jo-Jo Eumerus (talk, contributions) 06:22, 25 April 2019 (UTC)

• calibrated years ago – can this be explained at first mention?

Added a link at first mention. Jo-Jo Eumerus (talk, contributions) 06:22, 25 April 2019 (UTC)

• radiocarbon years ago – ditto

Added a link here as well. Jo-Jo Eumerus (talk, contributions) 06:22, 25 April 2019 (UTC)

• The now dried out basin was now exposed – two "now" mean different times here? Confusing.

Removed one "now". Jo-Jo Eumerus (talk, contributions) 06:22, 25 April 2019 (UTC)

• which blew dust out of the dried basin and is the single largest source of dust in the world. this change in tense seems to make no sense.

Changed this. Jo-Jo Eumerus (talk, contributions) 06:22, 25 April 2019 (UTC)

• A 4.2 kiloyear event is recorded in dust records and the Mediterranean and might – I don't understand.

Rewritten this a little; is it clearer now. Jo-Jo Eumerus (talk, contributions) 06:22, 25 April 2019 (UTC)

• If you wish to submit this to FAC in the future, I would seriously shorten it beforehand. It became too long for a single article. That is ok for becoming GA. --Jens Lallensack (talk) 02:58, 25 April 2019 (UTC)

  @Jens Lallensack: Thanks. Replied and addressed the comments. Regarding a potential FAC, according to Wikipedia:Featured articles/By length it would actually only be the thirty-longest FA if it were to pass at the current length ... but I see the point that such a super long thing is hard to review especially as it might become even longer in the future as more science about this is written. Jo-Jo Eumerus (talk, contributions) 06:22, 25 April 2019 (UTC)

It always depends on the article, whether excessive length is warranted for the topic or not. The last article I witnessed to fail at FAC just because of length was National Front (UK), which is much shorther than this one. --Jens Lallensack (talk) 21:21, 21 May 2019 (UTC)

• @Jens Lallensack:Eh, I'll see about this next Christmas, when the next big update (with papers published in 2019) is due. Jo-Jo Eumerus (talk, contributions) 21:50, 21 May 2019 (UTC)

• The end of the humid period appears to reflect the changes in insolation during the Holocene[78] with a progressive decrease thereof leading to decreased insolation gradients between Earth's hemispheres[470] but appears to have been much more abrupt than the insolation changes. – Sentence is very long and difficult to read. I don't understand the last part "but appears to have been much more abrupt than the insolation changes" – this reads to me like "the decrease of insulation was more abrupt than the insolation changes", which makes no sense.

  I've split it up a bit. Jo-Jo Eumerus (talk, contributions) 21:50, 21 May 2019 (UTC)

• the ITCZ – suggest to spell it out.

  Spelled it out everywhere. Jo-Jo Eumerus (talk, contributions) 21:50, 21 May 2019 (UTC)

• There might be differences between plants at higher versus these at lower latitudes, – perhaps just "differences between plants at higher and lower latitudes"?

  Yes, done. Jo-Jo Eumerus (talk, contributions) 21:50, 21 May 2019 (UTC)

• Decreases in polar insolation through altered cosmic ray fluxes … – remainder of the sentence does not seem complete, as it becomes a list without connections.

  That's because it is part of the list. Jo-Jo Eumerus (talk, contributions) 21:50, 21 May 2019 (UTC)

  I mean "thus stronger" does not connect well to the preceding part of the sentence. Needs slight reformulation I would say. --Jens Lallensack (talk) 17:55, 23 May 2019 (UTC)

  Did a small rewrite there. Jo-Jo Eumerus (talk, contributions) 19:03, 23 May 2019 (UTC)

• Additional feedback processes may have included the drying of soils and loss of vegetation after decreased rainfall[100] would led to wind-driven deflation of the soils. – "which would led"? --Jens Lallensack (talk) 21:21, 21 May 2019 (UTC)

  Remedied. Jo-Jo Eumerus (talk, contributions) 21:50, 21 May 2019 (UTC)

• including large-scale deforestation and for iron production during the Iron Age. – "and" is a word too much?

  Yes; removed it. Jo-Jo Eumerus (talk, contributions) 19:03, 23 May 2019 (UTC)

• Similar changes have been observed on the Adamawa Plateau[484] (Cameroon[466]) – Did you cite [466] just to source the fact that the Plateau is in Cameroon? This is not necessary.

  Aye, because the page of the source that discusses "Adamawa Plateau" does not mention that it is in Cameroon. Jo-Jo Eumerus (talk, contributions) 19:03, 23 May 2019 (UTC)

• between human expansion in Cameroon and environmental degradation – "Degradation" is always something negative. "Change" would be neutral (a desert is also an environment!). If humans had no influence, than we should use "change" imho. "Degradation" thus implies that humans had an influence, which is precisely what the sentence questiones (no correlation). Thus use "change"?

  I dunno, the sources that discuss the AHP often use "degradation" to refer to the desertification/drying. Jo-Jo Eumerus (talk, contributions) 19:03, 23 May 2019 (UTC)

• Climate-mediated feedbacks may have increased the fallout in East Africa – Too much technical speach I would argue. What kind of fallout?

  Replaced with "impact" and expanded a bit. Jo-Jo Eumerus (talk, contributions) 19:03, 23 May 2019 (UTC)

• In the Sudanian and Sahelian savannah on the other hand human activity seems to have had little impact – "on the other hand" indicates that human activity had an impact elsewhere. But no evidence for this was provided in the preceding sentences (just one study that did not find a correlation, and some facts without explicit interpretation in this direction).

  This is somewhat complex. Basically, there is an open controversy about how much human activity impacted on the environment in Central Africa and that controversy is not settled. Elsewhere on the other hand evidence for human impact is much more scant. The source cited for this statement is summarizing other research articles. Jo-Jo Eumerus (talk, contributions) 19:03, 23 May 2019 (UTC)

• Claussen et al. – I was told we should avoid "et al." in Wikipedia, as it is too technical. --Jens Lallensack (talk) 18:12, 23 May 2019 (UTC)

  I suggest "and colleagues" instead of et al. --Jens Lallensack (talk) 19:43, 23 May 2019 (UTC)

  @Kens Lallensack: Done. Jo-Jo Eumerus (talk, contributions) 19:47, 23 May 2019 (UTC)

  @Jens Lallensack: Jo-Jo Eumerus (talk, contributions) 19:48, 23 May 2019 (UTC)

  Hrm, would it work better to spell the names out? Jo-Jo Eumerus (talk, contributions) 19:03, 23 May 2019 (UTC)

• @Jens Lallensack: Jo-Jo Eumerus (talk, contributions) 19:03, 23 May 2019 (UTC)

• Such human migrations towards more hospitable conditions along rivers and the development of irrigation also took place along the Euphrates River, Tigris River and Indus River, leading to the development of the Sumerian and Harappan civilizations. – Sumer started 6500 years ago, before the end of the humid period and much earlier than the Harappan civilization? Furthermore, I think the info that the Harappan civilization used irrigation is outdated, see here for a summary: [1]

  I dunno. Sumer suggests that the society there started a few millennia later, or at least the urban aspects. Also, the Arabian AHP might not have ended at the same time as the Africa one. I am guessing this is just the problem with linking two separate events with an uncertain chronology but I don't recall seeing any sources that explicitly rule out a connection between climate drying and the onset of Mesopotamian civilization. Regarding the Harappan civilization, is that study the last word on the irrigation question? The source in the article is from one year later and says The increasingly arid conditions at the end of the African Humid Period forced human agropastoral societies to improve their organization in order to optimize natural resources, in particular freshwater supplies (7). As a result of growing demographic pressure in an environment that was again becoming hostile, Neolithic communities were forced to concentrate in river valleys and to develop irrigation systems. These complex transformations help explain the rise of the Egyptian, Sumerian, and Harappan civilizations that flourished along major rivers such as the Nile, Euphrates, Tigris, and Indus. Jo-Jo Eumerus (talk, contributions) 09:57, 30 May 2019 (UTC)

  I think so, the paper cites other works supporting the lack of irrigation. But should be checked in any case. --Jens Lallensack (talk) 12:46, 30 May 2019 (UTC)

  @Jens Lallensack: Hmmm. Well, the article here probably should still say that the end of the AHP is linked to the onset of the Harappan civilization. I am not sure how to separate the "irrigation" aspect; maybe say "often with irrigation" rather than just "irrigation"? Jo-Jo Eumerus (talk, contributions) 13:52, 30 May 2019 (UTC)

  Yes, formulating it a bit less definitive should do the trick! --Jens Lallensack (talk) 13:56, 30 May 2019 (UTC)

• the development of elites the increased presence of human – misses a ","?

  Yes, added it. Jo-Jo Eumerus (talk, contributions) 09:57, 30 May 2019 (UTC)

• desert i.e. a – also misses two ","?

  Also added. Jo-Jo Eumerus (talk, contributions) 09:57, 30 May 2019 (UTC)

• occurs through different methods – I guess you mean "mechanisms"?

  Yes, changed that. Jo-Jo Eumerus (talk, contributions) 09:57, 30 May 2019 (UTC)

• That's all, finally. I'm relieved to got this done! --Jens Lallensack (talk) 09:24, 30 May 2019 (UTC)

  Thanks for the review Jens Lallensack. Jo-Jo Eumerus (talk, contributions) 09:57, 30 May 2019 (UTC)

• The article is promoted now. Congratulations! For further improvement, I would strongly suggest to find ways to shorten this article, moving text into sub-articles and such. --Jens Lallensack (talk) 14:02, 30 May 2019 (UTC)