Earlier quoted context omitted.
I would like you to answer my questions concerning "how you came across this paper, and what about it lead you to conclude it was a more accurate source of information". You haven't done that. Obviously I am not suggesting what you think I did, as I've already answered your question by saying "we've improved our understanding of the temperature records" since 25 and 50 years ago, respectively. I don't think you are d…
I don't need to answer how I came across some source. That's irrelevant. If you have conflicting sources of information, I'll gladly purview them, but don't be condescending or patronizing. It's super counter-productive. We still don't understand what caused D-O events, but we know one thing for sure: CO2 was an independent variable in those events. Warming occurred in times when CO2 concentrations were decreasing. W…
But the other half of my question was, "what about it lead you to conclude it was a more accurate source of information" than the xkcd comic and its sources. Is that question also patronizing?
You write "If you have conflicting sources of information, I'll gladly purview them".
I already pointed out how your references conflict with the references given in the xkcd comic. You replied "I don't know why there's differences between these sources and the one you are quoting."
Is that your definition of gladly purviewing conflicting references?
What is the point of your new references? They seem to have no bearing on the topic of why you think Nurtaev and Nurtaev is a more accurate source of information than the xkcd comic and its references.
I therefore cannot help but think that you are pulling off a "Gish Gallop" - https://en.wikipedia.org/wiki/Gish_gallop - which "focuses on overwhelming an opponent with as many arguments as possible, without regard for accuracy or strength of the arguments"
I'll give just two examples why I think your references have little bearing on the topic. You cite Quansheng et al., though with a mutilated set of names which shows a bad copy and paste.
The warm period in China was mentioned already in the Wikipedia link I gave already, in the sentence before the one I quoted. The longer quote is:
"likely[1] related to other warming events in other regions during that time, including China[2] and other areas,[3][4] lasting from c. 950 to c. 1250.[5] Other regions were colder, such as the tropical Pacific. Averaged global mean temperatures have been calculated to be similar to early-mid 20th century warming."
If you "gladly purview" conflicting sources, then the Wikipedia article I mentioned was already a conflicting source to the Nurtaev and Nurtaev graph. (Note that neither the Wikipedia article nor Nurtaev and Nurtaev were primary sources for the relevant information.)
If you want something from the literature, Jin, C., Liu, J., Wang, B., Wang, Z., & Yan, M. (2018). A Centennial Episode of Weak East Asian Summer Monsoon in the Midst of the Medieval Warming. Paleoceanography and Paleoclimatology. doi:10.1029/2017pa003264 link the warming in China to "the low solar radiation during that period, which leads to a prevailing El Nino-like Indo-Pacific cooling with a strong cooling center occurring in the equatorial western Pacific."
This is in accord with the Wikipedia reference, meaning that if you are serious about looking at your sources then you would have read the IPCC notes that the warming signals of the Medieval Warming Period lacked global consistency, and should more properly be called Medieval Climate Anomaly.
So you need to show global effects. Which I think you tried to do by pointing to "evidence of Medieval Warm Period in Antarctica (offset by about 150 years from Northern hemisphere's warming period)"
However, 1) the authors of that paper describe it in the abstract as "Southern Hemisphere Medieval Warming–like period?", including the question mark, which hardly justifies the strength of your final conclusion, 2) the paper doesn't actually present evidence for a Medieval Warm Period in Antarctica, but rather shows that their evidence is not incompatible with the MPW-like proposal of Goosse et al., and 3) with a 150 year delay (as estimated from numerical simulation) we aren't talking about a global warming period. The Gosse paper points out the warmest time in the Antarctic seems to be around 1250–1450, which is after the MWP in the Northern Hemisphere, making it an example of how the Nurtaev and Nurtaev paper, which depends on older and less complete data sources, must be modified to reduce the temperature swings to better reflect global conditions.
That is, they emphatically do not "all indicate a strong [globally synchronized multi-decadal] Medieval Warm Period just as warm as today". They instead indicate many regional warmings. While at the same time they support my claim that Nurtaev and Nurtaev is not as accurate as the xkcd comic.
Hence, if you believe those papers are accurate, why do you think that the chart in Nurtaev and Nurtaev was more accurate than the one from xkcd?