How neat to have a reference to the Journal of the Georgian Geophysical Society. I so rarely get to see Georgian script, like in the subsequent paper by ბ. ნურტაევი and ლ. ნურტაევი (last page on the document).
What makes it odd, however, is that the chart you mentioned is an uncited reprint of a chart made by noted global warming denialist David Archibald. See https://wattsupwiththat.com/2011/02/12/david-archibald-on-cl... . You'll note that this paper by Nurtaev and Nurtaev uses a low quality image paste, so almost certainly did not generate it themselves.
Also odd is the source citations, from Dansgaard (1969) and Schönwiese (1995). You'll note that those are 1) not stated in the references, and 2) they are very old, at 50 and nearly 25 years, respectively.
Compare that to the citations in the xkcd comic, which are to 2012 and 2013.
This is important because we've improved our understanding of the temperature records. The xkcd comic notes "Medieval warm period in Europe and some northern regions (too regional to affect the global average much)" and Wikipedia's entry for the Medieval Warm Period comments "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"
While the chart in Nurtaev and Nurtaev says there is a distinct global warming during that period.
How odd that they use information which is so out of date.
How odd that the paper promotes a solar model which has long been demonstrated to be wrong - and mostly only lives among the fringe group of global warming denialists.
How odd that you decided to post a link to this paper, instead of the source material, and argued that it was more accurate when it appears to be less.
Could you describe how you came across this paper, and what about it lead you to conclude it was a more accurate source of information?
Are you suggesting that studies or papers which have been published more recently are automatically more correct? I think that's an incredulous statement and suggests a recency bias in your line of thinking.
Dansgaard was the guy who discovered that isotopes in ice cores could be used to measure past climates.
In particular, when we are discussing climatic events from 300, 1000, and many millennia ago, these events have ice core records that have not changed. And unless you have evidence of Dansgaard's faulty measurements of said isotopes, you've got to accept this as scientific fact:
The climate has warmed as much as 8 degrees Celsius in less than 40 years in the prehistoric past.
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 denying that fact, just like I don't think you are suggesting that that older sources of information are automatically more correct than more recent ones.
I'm asking why you believe the publication you pointed to is more accurate than the xkcd comic.
What's the point of bringing up the Dansgaard–Oeschger events? The most recent D-O event was about 11,500 years ago, while the chart in Nurtaev and Nurtaev only goes back to 11,000 years ago.
Plus, if you believe the smoothing in Nurtaev and Nurtaev is valid then you must surely believe the smoothing in the xkcd comic is valid.
If you don't like the smoothing in the xkcd comic, the relevant source - cited as Marcott et al. (2013) - is "A Reconstruction of Regional and Global Temperature for the Past 11,300 Years", in Science, available from http://content.csbs.utah.edu/~mli/Economics%207004/Marcott_G... . You'll note it cites Oeschger, and describes the 73 globally distributed records used, and several different methods used to estimate the global temperature anomaly, along with associated errors.
How did Nurtaev and Nurtaev come up with their graph, that being a paper which you suggest is a good source for scientific argument? Which temperature records were used? How was the curve fitting done? What are the estimated errors?
Quite clearly at least one of them is wrong as Nurtaev and Nurtaev give a 0.5C global temperature rise above baseline during the "Medieval warm period", while Marcott et al. show it at about baseline, with a 0.5C temperature rise being above the uncertainty band.
How did you decide that the Marcott et al. paper (and hence xkcd) is less likely to be correct than Nurtaev and Nurtaev?
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. We know that during these events, global temperatures bounced as much as 8 degrees Celsius in as little as a few dozen years, indicating that rapid climate change is naturally possible. We can speculate that whatever natural forcing caused those changes to occur could potentially occur at any time.
I'm going to show you several sources (that are not Nurtaev) that indicate swings of 4+ degrees Celsius in the past 10,000 years and that bears some level of investigation. I don't know why there's differences between these sources and the one you are quoting.
Peta J. Mudie, Andre Rochon & Elisabeth Levac (2005) Decadal-scale sea ice changes in the Canadian Arctic and their impacts on humans during the past 4,000 years, Environmental Archaeology, 10:2, 113-126, DOI: 10.1179/env.2005.10.2.113 https://doi.org/10.1179/env.2005.10.2.113
Loehle, C. (2007). A 2000-Year Global Temperature Reconstruction Based on Non-Treering Proxies. Energy & Environment, 18(7), 1049–1058. https://doi.org/10.1260/095830507782616797 (shows past 2000 years including Medieval Warming Period and Little Ice Age with much greater perturbations than indicated by Marcott et al.)
Quansheng GeHaolong LiuXiang MaJingyun ZhengZhixin Hao (2017). Characteristics of temperature change in China over the last 2000 years and spatial patterns of dryness/wetness during cold and warm periods. Advances in Atmospheric Sciences. August 2017, Volume 34, Issue 8, pp 941–951. https://link.springer.com/article/10.1007%2Fs00376-017-6238-...
^^ shows Medieval Warm Period just as warm today "as data show records for the periods AD 981–1100 and AD 1201–70 are comparable to the present"
Holocene volcanic history as recorded in the sulfate stratigraphy of theEuropean Project for Ice Coring in Antarctica Dome C (EDC96)ice core. Holocene volcanic history as recorded in the sulfate stratigraphy of theEuropean Project for Ice Coring in Antarctica Dome C (EDC96)ice coreE. Castellano,1S. Becagli,1M. Hansson,2M. Hutterli,3J. R. Petit,4M. R. Rampino,5M. Severi,1J. P. Steffensen,6R. Traversi,1and R. Udisti. https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/200...
^^ evidence of Medieval Warm Period in Antarctica (offset by about 150 years from Northern hemisphere's warming period)
Yi, S., Saito, Y., Chen, Z. et al. Geosci J (2006) 10: 17. https://doi.org/10.1007/BF02910329 Palynological study on vegetation and climatic change in the subaqueous Changjiang (Yangtze River) delta, China, during the past about 1600 years.
^^ Research indicating 1-2 degrees Celsius warmer in China during Medieval Warming Period.
So the research above depends on both ice cores and tree rings, analyzed completely independently of each other in completely different regions around the world. They all indicate a strong Medieval Warm Period just as warm as today and a strong Little Ice Age, probably 1-2 degrees colder than today, in just the past 1000 years.
Okay, don't answer how you came across an article in the Journal of the Georgian Geophysical Society.
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?
What makes it odd, however, is that the chart you mentioned is an uncited reprint of a chart made by noted global warming denialist David Archibald. See https://wattsupwiththat.com/2011/02/12/david-archibald-on-cl... . You'll note that this paper by Nurtaev and Nurtaev uses a low quality image paste, so almost certainly did not generate it themselves.
Also odd is the source citations, from Dansgaard (1969) and Schönwiese (1995). You'll note that those are 1) not stated in the references, and 2) they are very old, at 50 and nearly 25 years, respectively.
Compare that to the citations in the xkcd comic, which are to 2012 and 2013.
This is important because we've improved our understanding of the temperature records. The xkcd comic notes "Medieval warm period in Europe and some northern regions (too regional to affect the global average much)" and Wikipedia's entry for the Medieval Warm Period comments "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"
While the chart in Nurtaev and Nurtaev says there is a distinct global warming during that period.
How odd that they use information which is so out of date.
How odd that the paper promotes a solar model which has long been demonstrated to be wrong - and mostly only lives among the fringe group of global warming denialists.
How odd that you decided to post a link to this paper, instead of the source material, and argued that it was more accurate when it appears to be less.
Could you describe how you came across this paper, and what about it lead you to conclude it was a more accurate source of information?