Talk:Medieval Warm Period

Winemaking
We seem to have lost the old arguments that winemaking in medieval times proved the MWP, but a useful source covers the 2017 situation: Maybe worth citing. . . dave souza, talk 18:41, 20 May 2017 (UTC)

Well we should note that the commonly cited claim that the Romans grew vineyards in England and that this is not possible today would be a surprise to the thriving British wine industry which has circa 700 vineyards as far North as Yorkshire and over 140 commercial wine producers! 213.205.194.181 (talk) —Preceding undated comment added 19:26, 16 June 2019 (UTC)


 * Apparently studies of the Medieval Warm Period are now considered "off-message", as the findings must should a permanently cold period followed by warmth following industrialisation. However the Renaissance of the 12th century was helped along by warmer weather.78.16.91.213 (talk) 09:28, 19 August 2019 (UTC)
 * Note: No one has suggested that there was "a permanently cold period followed by warmth following industrialisation". This misrepresents the discussion completely, which is: was the MWP a global event or not.  The very considerable empirical evidence seems to suggest that it wasn't. BobBadg (talk) 13:24, 8 August 2023 (UTC)
 * Also the use of weasel words "off-topic" is implying, pretty blatantly, that research is biased to find some answers and suppress others. It would be more honest to say "I am a climate change denialist" and have no belief in the objectivity of science". BobBadg (talk) 13:31, 8 August 2023 (UTC)

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Improvements
I remember this article as being pretty good, i came back to it as part of a project and i find that it has been blasted into a mishmash of quotes such as 'evidence does not support globally synchronous periods...' seriously? including these quotes does not help, they need to be paraphased in simpler terms; intermingled with an attempt to expand the article to cover a worldwide view with no real research to support any such attempt. It is fairly obvious that this is a mostly European weather event (its in the IPCC reports), but it has been half-dragged into some climate/global warming debate, to the detriment of article quality. also the graph used in no way illustrates the topic, it merely serves to show how hot we are now globally with confusing lines that make it hard to see whats going on, compare this to the chart that has been left on the talk page, more specific to greenland (which is also not really illustrative). note how greenland was much hotter during this climate/long-term weather event, whereas global warming has not affected greenland as much (because global warming is a pervasive global event rather than a localised pattern. there is no doubt that greenland was hotter, but the world was colder). a more suitable graph would be for a longer time period, with smoothing adjustments, covering European average yearly temperature. this is separate to the issue of whether 'climate change' is real or not, this article is supposed to be neutral. i wont go into the details of the debate but basically this article can show the data without being biased, but is not currently succeeding. i propose to remove and disallow all references and mentions of climate change or events after 1900 from this article completely. instead write the article based on comparison to prior events, and perhaps a bit on the affects it had on winemaking/northern trade/culture/greenland could be added. A Guy into Books (talk) 22:14, 13 August 2017 (UTC)

There's a couple largely unreferenced broad claims in here that should be refined and sourced. At the beginning, "Modern knowledge of the Medieval Warm Period is uncertain, especially for the period prior to c. 1600 for which there is limited climate data." No source, in addition to the claim just not being intuitive scientifically (why wouldn't we have data in that gap). Similar issue in the next sentence, "It is thought that between c. 950 and c. 1100 was the Northern Hemisphere's warmest period since the Roman Warm Period." Needs some follow up and citation there.

Secondly, the discussion is a bit biased towards discussion of North America and leaves the other continents largely bare of info. There may be a weighted distribution of research on this period in other places, but nonetheless this section can be expanded.

Nrchristman (talk) 00:43, 30 September 2017 (UTC)

Well basically this was written by Americans, most the research is American, and the research on this topic is so insanely contradictory (even from the same reports) that writing anything is difficult. There is not as much climate data for pre 1600, because it is harder to find trees, ice etc to extract the data from that have remained untouched from that period. It is generally known that this event did not effect most of the world, only Europe and North America. The lack of references is because this contentious topic is often hijacked by climate change deniers and global warming doom activists alternately. each claiming each others work is fringe BS. Dysklyver 14:54, 30 September 2017 (UTC)

Source for timing not synchronous

 * | access-date=11 August 2019}} discusses three studies, including one covering this topic. The first reference is shown below, can add others on request. . . dave souza, talk 10:47, 19 August 2019 (UTC)
 * – don't have access, but Johnson is clear that it's on-topic. . . dave souza, talk 10:47, 19 August 2019 (UTC)

Disputed: Misquote from AR6?
The page claims that "In August 2021, the 6th IPCC report indicated that global temperature was 4°C– 10°C warmer during the MCO than 1850-1900.[21]". This is in direct contradiction to the figure at the top of the page, which shows more like a 0.1° difference. Therefore I am pretty sure that this new statement about AR6 is completely wrong. Unfortunately, the citation is only to AR6, and since that is nearly 4000 pages long, I can't search for where this 4-10°C number is supposed to come from. I suggest deleting this! 85.4.149.121 (talk) 16:39, 6 September 2021 (UTC)Martin


 * I was looking for the same thing. Can anyone provide a more specific citation here, or edit the page to reflect that a more specific citation is needed? Gralgrathor (talk) 14:14, 15 September 2021 (UTC)

I actually found the quote, and the reason for the totally wrong number. AR6 uses a lot of abbreviations, one of which is MCO, which is defined as "Miocene climatic optimum**(MCO)" on page 2-11 (or 440 of the pdf) of the technical report. This is "16.9-14.7 Ma" ago, so millions of years ago. In contrast, "Mid-Holocene (MH)", "6.5-5.5ka" ago is where "Middle of the present interglacial when the CO2 concentration was similar to the onset of the industrial era, but the orbital configuration led to warming and shifts in the hydrological cycle, especially NH monsoons. Approximate time during the current interglacial and before the onset of major industrial activities when GMST was highest." (still on page 440 of the pdf). On page 462 of the pdf (or page number 2-33) there is the statement "AR5 did not assess the GMST for the MCO. Reconstructions based on data from multiple study sites include estimates of about 4℃ (uncertainty range not specified; You et al., 2009) and 5°C–10℃ (2 standard error range; Goldner et al., 2014) warmer than 1850–1900. Together, these studies indicate that GMST was 4°C–10°C warmer during the MCO (medium confidence)." The author of the disputed misquote must have taken MCO to refer to medieval climate optimum rather than miocene climate optimum. Having found this, I will delete the erroneous information from the article! Oops, can't, someone already did 4 days ago! Martin


 * Thanks for finding the source of confusion. I rm'd the text William M. Connolley (talk) 18:45, 21 September 2021 (UTC)


 * Mea culpa, thanks for fixing it. Forich (talk) 15:27, 18 October 2021 (UTC)
 * Don't worry I forgive you :-) William M. Connolley (talk) 16:38, 18 October 2021 (UTC)