Talk:Medieval Warm Period/Archive 1

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Early talk

Steve, thanks for starting this article. I just put it on my to-do list today, and -- voila! -- it appears.

The period is also called the Medieval Climate Optimum, and I'm not sure if all sides in the global warming controversy admit its existence. It flies in the face of IPCC claims that the 1990s were the warmest decade of the millenium.

By the way, welcome to Wikipedia! -- User:Ed Poor

Thanks, Ed! I discovered Wikipedia just a week or so ago, and I'm hooked. As if I need something like this in my life eating up what little time I have. :) The welcomes I've gotten from the old hands here has been great.

All of my knowledge of the MWP comes from the Web. I'm aware that a couple of years ago someone came out with a book or paper or something asserting that the MWP was at most a localized phenomenon, and it seems to have gotten a great deal of publicity precisely for the reason you mention. I've also seen at least one rebuttal of that person's rebuttal of the MWP.

When/if I get around to filling out this article ... or perhaps if you should undertake it ... we need to include something on the MWP controversy.

Personally, I like knowing that there may have been a fairly recent time when things were even warmer than they are now. Being from the Deep South, I'm finding even North Carolina too frigid for my blood. Bring on global warming! :)

-- Steve User:SteveSmith

(William M. Connolley 21:48, 15 Nov 2004 (UTC)) See:

Dr. C., do you mind if I mention the fact that the IPCC had initially accepted the MWP? Then you can explain what made them change their mind. Deal? --user:Ed Poor (deep or sour) 22:06, Nov 15, 2004 (UTC)

(William M. Connolley 23:01, 15 Nov 2004 (UTC)) It would be a really good idea if you knew what you were talking about, though. You can't rely on the Idso's, sadly. If you really care (and you seem to) you can find the TAR on the web. The SAR, 1992 and 1990 aren't, but they wouldn't set you back much from abebooks. About $10 apiece [1]. You won't, of course, because you can't be bothered.
Well, then there is a dispute in the scientific community about whether the Idso's can be relied upon. Dr. C on the BAS says they are unreliable (may I quote you as an authority in the article?). --user:Ed Poor (deep or sour) 15:06, Nov 16, 2004 (UTC)
(William M. Connolley 17:23, 16 Nov 2004 (UTC)) The issue is facts. Stop trying to turn it into personalities. This page here is about MWP, not for arguing about IPCC. Go read the MWP and LIA in IPCC reports if you want to argue that. Though you will, of course, be crippled because *you have never bothered to read the IPCC reports*. You insist on relying on second hand sources, even though the IPCC reports can be had for a few dollars. No, you cnnot quote me as an authority.
Since William says this page is about the MWP, I have removed all reference to modern warming trends since, according to him, they have no place here.--JonGwynne 23:13, 9 Feb 2005 (UTC)

WMC playing partisan games again

I am particularly amused by his repeated attempts to remove references to the cooling trend in the 20th century - presumably because it doesn't conform to his prejudices. Tsk, tsk William, this isn't how a scientist is supposed to behave.--JonGwynne 20:00, 6 Feb 2005 (UTC)

(William M. Connolley 21:48, 6 Feb 2005 (UTC)) As we all know, the mid-century cooling is perfectly explained by GCMs (sulphate cooling plus natural var) and thus amounts to a *confirmation* of climate models and GW theory. So no, I have no objections to the existence of the mild cooling trend.

Then why do you keep deleting it?--JonGwynne 23:23, 6 Feb 2005 (UTC)
Sorry, Revert-Boy, but you're not allowed to remove relevant information just because you don't like what it says. Oh yeah, and see how I can restore the integrity of the article without resorting to petulant reversion? Perhaps you might learn from this example, but you'll forgive my I hope if I don't hold my breath...--JonGwynne 12:54, 7 Feb 2005 (UTC)
(William M. Connolley 14:20, 7 Feb 2005 (UTC)) You are lying. You have simply reverted the article but failed to mark your revert as such.
Once again you're the liar. A trained monkey could use the comparison tool and see that my recent edits are all significantly different. Why is this beyond your capabilities? I know you're smarter than a trained monkey, why can't you do it? Is is that you can't? Maybe it is that you just won't. You're obviously not stupid or blind. What's the problem? OK, I'll make you happy. I'll revert it.--JonGwynne 00:12, 8 Feb 2005 (UTC)
(William M. Connolley 21:11, 8 Feb 2005 (UTC)) Making cosmetic changes that are substantive reverts are still reverts.
I don't make "cosmetic changes". I sometimes rewrite things, but that is a different matter. Let me see if I understand this, you know that my different edits are different and yet you insisit on dishonestly referring to them as revert anyway? Hmmm, that makes you a liar. But then I've known that for some time. It just puzzles me that keep at it even after having been revealed as such. A better man would have apologized and undertaken not to repeat the mendacious behavior.

Removed blatant and senseless personal attack by User:smithsmith Vsmith 02:21, 24 January 2006 (UTC)

Time for civility

(William M. Connolley 15:20, 17 Feb 2005 (UTC)) I've removed (twice now) a personal attack by JG on this talk page, under the [[2]] rules.

I think its time for a campaign for civility on this pages, and respect for the NPA rules. Obviously, this won't work if it simply degenerates into a revert war between me and JG - so I would ask other editors to help out.

I have no interest in censoring peoples opinions, or indeed or preventing us criticising others views, but it is time (long past time) that the rules on doing this in a civilised manner were enforced.

Sorry William, you don't get to remove other people's statements from this record. Comment on them or not as you like, but you aren't entitled to remove or edit them. You should have learned your lesson on the MC discussion board. --JonGwynne 15:01, 17 Feb 2005 (UTC)

In the meantime, William is again resorting to lies. He claims I reverted when it is perfectly clear that the material I put in place was new. Since he is too lazy to show the comparison (and for the convenience of those who'd like to check it themselves), here is the link: Proof of Williams continuing campaign of lies --JonGwynne 15:14, 17 Feb 2005 (UTC)

Definitely time for civility. And yes, we can edit out your rude and disparaging comments for civility see here. And if you persist in your namecalling: Personal attacks are not allowed on Wikipedia. Although users can of course ignore them, repeat offenders can be reported to the administration and temporarily or permanently banned. This has happened in some cases of users who frequently insulted other users, even though they also had made valid contributions. [3] --Vsmith 18:16, 17 Feb 2005 (UTC)
The page to which you refer when you talk about editing other people's remarks carefully announced in its header that it is "not currently policy". As regards William's mendacity, how would you suggest I describe it? There aren't that many synonyms for the word "liar". However, I'll make you a deal: if you come up with one, I'll consider using it. Is that fair? My understanding of the wikipedia policy is to address situations where one user is calling another one names like "scumbag" or "asshole" or something like that. I don't see that it should exclude objective, factual descriptions. That is why I feel entitled to use words like "liar" or "hypocrite" when they are used as literal descriptions rather than insults. I realize that these comments may annoy the people whose behavior is being described but I believe it is counterproductive for the rest of us to sit by and allow their objectionable behavior to continue without comment. This would tend, in my view, to encourage such behavior rather than discouraging it as I believe should be the case.--JonGwynne 18:48, 17 Feb 2005 (UTC)
p.s. speaking of hypocrisy, it is pretty rich to hear WMC complaining about lack of civility when he makes statements like "It would be a really good idea if you knew what you were talking about, though" from his comments to Ed above.--JonGwynne 18:48, 17 Feb 2005 (UTC)
Jon, I don't know where you learned manners, but, in civil discussions calling someone a liar and a hypocrite are definitely insulting and non-civil and are in no way: objective, factual descriptions. How about: "I disagree with your interpretations for the following reasons:" as a replacement for "liar". Your rude comments appear to be designed to instigate a negative response rather than to come to any mutual understanding of each other's point of view or to any resolution to the disagreement and therefore are counter-productive.
Also Jon, I have tried to be civil with you and in response you call me a "vandal" when I disagree with you. I consider that an insult and quite uncivil. Civility means respectful comments, not just avoiding vulgarities and profanity as your comments above seem to indicate your interpretation to be.
Civility also includes fair, honest and descriptive edit summaries. Ideally we work here in an environment of trust; and deceptive edit summaries spoil that trust. I have learned from experience with you that I cannot trust your edit summaries, as you seem to have an aversion to honestly summarizing your edits. Trust must be earned and it is critical to civil discourse. -Vsmith 01:43, 18 Feb 2005 (UTC)

"Liar. (noun) One who tells lies". That's an objective, factual description. If a liar takes offense at being called a liar, that is the liar's problem, not the person reporting the lie. So is "hypocrite. (noun) a person given to acting according to a double-standard. i.e. a person who complains about behavior in others that they demonstrate themselves". Again, I can't be worried about the feelings of hypocrites. If they object to being called hypocrites, they can stop being hypocrites. Simple. Sorry but, "I disagree with your interpretations for the following reasons:" isn't an accurate alternative for "liar". It doesn't mean the same thing. If you want to offer me a valid subsitution, it needs to capture the elements of describing the willful or negligent expression of a falsehood.--JonGwynne 00:53, 21 Feb 2005 (UTC)
I use the word "vandal" or "vandalism" to describe the wanton destruction of someone else's work with no valid reason. For example, the repeated and pointless abuse of the table of greenhouse gasses. There is simply no excuse for it. There is no factual disagreement, it is simply a list of gasses as produced by the IPCC. To remove gasses from that list arbitrarily and/or to render the table unreadable by certain web browsers is simple vandalism. If someone doesn't like being called a vandal, they should stop committing vandalism. I don't call someone a vandal because they disagree with me, I do it when they commit vandalism. Though, to be fair, I don't always do it. Sometimes I give them the benefit of the doubt, if there is one.--JonGwynne 00:53, 21 Feb 2005 (UTC)
You complaint about edit summaries is puzzling. The edit summary is a comment field only. If you want to see what changes have been made, use the comparison tool. That's what it is there for.--JonGwynne 00:53, 21 Feb 2005 (UTC)
As far as respectful comments go. I show people exactly the same level of respect they show me. I proceed on the assumption that people deal with me as they would have me deal with them. If they don't like how I interact with them, they should take a long look at how they're acting toward me. Since you're so keen on respectful comments, I wonder if you'll chastize William for calling me a degenerate. I wonder if you'll hold him to the same standard you're trying to hold me. Hmmm, this will be an interesting test of your character. Will you show your objectivity and admonish William? We'll see...--JonGwynne 00:53, 21 Feb 2005 (UTC)

Discussion of IPCC Reports belongs in the section marked IPCC reports

On what basis would anyone argue otherwise? --JonGwynne 18:36, 16 May 2005 (UTC)

(William M. Connolley 20:30, 16 May 2005 (UTC)) Discussion of whether the periods were global or not isn't restricted to the IPCC, and implying so is POV pushing. In this (as in other things) the IPCC is merely summarising the published research.
The source of the claim is an IPCC report, ergo the section in which it it properly discussed is the one called "IPCC Reports". Whether or not they are summarizing other people's research is beside the point in this case. --JonGwynne 06:29, 19 May 2005 (UTC)
(William M. Connolley 17:47, 19 May 2005 (UTC)) Which succintly condemns you out of your own mouth. That you don't even understand why just indicates why you shouldn't be trying to edit science articles.
So now WMC is claiming the IPCC is transparently passing through reports from scientists? The IPCC no longer forms a consensus, it just is listing stuff, thus only the scientific reports matter? So you can just delete mention of the IPCC? (SEWilco 18:43, 19 May 2005 (UTC))
(chuckle) Maybe WMC is the one who shouldn't be editing science articles since he dosn't seem to fully grasp the role of the IPCC. --JonGwynne 18:42, 23 May 2005 (UTC)
(William M. Connolley 19:27, 19 May 2005 (UTC)) I've always been claiming that IPCC accurately reports the balance of the science, and to that extent is transparent. Didn't you realise? But no, deleting IPCC would not make sense, since they do perform a valuable role in doing the summarising.
You statement is inherently contradictory. Either the IPCC is transparent or it isn't. It can't be both. Seesh... and you claim *I'm* the one who doesn't "get it"?


Stuff from a quick look at grapes, not including English grape business being affected by a wedding. (see "New Wine into Old Bottles")[4] (SEWilco 06:42, 20 May 2005 (UTC))

Temporary injunction

Copied here from Wikipedia:Requests for arbitration/William M. Connolley and Cortonin#Temporary injunction:

Since revert wars between the Cortonin and William M. Connolley have continued through this arbitration, both users are hereby barred from reverting any article related to climate change more than once per 24 hour period. Each and every revert (partial or full) needs to be backed up on the relevant talk page with reliable sources (such as peer reviewed journals/works, where appropriate). Administrators can regard failure to abide by this ruling as a violation of the WP:3RR and act accordingly. Recent reverts by Cortonin [5] [6] [7] [8] [9] by William M. Connolley [10] [11] [12] [13] [14] Additional reverts by others involved in these revert wars may result in them joining this case.

--mav 22:50, 23 May 2005 (UTC)

Rv to WMC

(William M. Connolley 15:31, 25 May 2005 (UTC)) I've reverted to WMC. JG made huge reversions, under the deliberately misleading edit summary of "Various edits, grammar correction, fixing of spacing and formatting". Remember folks, JG regularly uses misleading edit summaries - you need to check what he has done, and not believe the summaries.

So: JG removed:

Initial research on the MWP and LIA was largely done in Europe, where the phenomenon was most obvious and clearly documented. It was initially believed that the temperature changes were global. However, recently this view has been questioned (Bradley and Jones, 1993; Hughes and Diaz, 1994; Crowley and Lowery, 2000). The 2001 IPCC report summarises this research, and concludes: "…current evidence does not support globally synchronous periods of anomalous cold or warmth over this timeframe, and the conventional terms of 'Little Ice Age' and 'Medieval Warm Period' appear to have limited utility in describing trends in hemispheric or global mean temperature changes in past centuries" [15].

down into a section called IPCC reports. This is wrong: its not IPCC research, its just that the IPCC is the most convenient way for most people to find it.

I was disappointed to see SEW editing on top of this distortion by JG. SEW has previously accepted that JGs change is inappropriate: it would seem that his conversionis rather half-hearted and his skeptic side breaks out given an excuse. The Jones and Mann para is also highly relevant, and belongs in the intro.

I had already moved Jones and Mann to the intro, in the "editing on top" which you saw. Odd that agreeing with you is a disagreement. As you say the IPCC is not as important as the research, I'll remove the contentious references to IPCC. (SEWilco 18:01, 26 May 2005 (UTC))

(William M. Connolley 19:59, 26 May 2005 (UTC)) I've reverted, of course. Why are you doing this? In detail:

Globality of MWP

  • The globality or otherwise of the MWP is important. It belongs in the intro. Shuffling it down is POV.
It is a minority view that its effects were not global. I'm pretty sure previous versions had different phrasing in the intro to reduce its globality, or maybe that was in LIA. I'll do it again here. (SEWilco 21:02, 26 May 2005 (UTC))
(William M. Connolley 16:16, 27 May 2005 (UTC)) Who says its a minority view? You? Which reference? Come on, you're making this up as you go along. I think its actually the majority view, and definitely deserves being in the intro.
As the article says, "recently this view has been questioned", because the majority view was questioned. The IPCC link only gives a few references about the MWP. For that matter, the IPCC gives warming in eastern China as an example of lack of a global MWP because western China did not also warm; hardly surprising as, western China is the different climate of the Tibetan Plateau and is next door to the Siberian High. The lack of warming in the warm tropics is hardly surprising, as warming has the greatest effect closer to the poles (or so I've been hearing). And researchers are still referring to the MWP. (SEWilco 18:02, 27 May 2005 (UTC))
(William M. Connolley 18:27, 27 May 2005 (UTC)) You are defending the indefensible. Quite possibly the article wording should be revised - "recently" is rather vague, and its been questionned for quite a while now (the first ref is from 1993 after all). So, to be clear, you have no real idea whether its a minority view or not. You have no refs for it, only inference based on *my* phrasing. If you're going to lean on my authority so heavily, please don't cherry-pick.

The evidence points to a global effect during the Medieval Warm Period, Connelley. You should know that being that you are a climate scientist. Evidence has been gathered from North America which supports the globality of it.

Identification of MWP

  • The Jones and Mann quote doesn't belong in the climate events section.
    Jones and Mann (2004) note that most paleoclimatologists developing regionally specific climate reconstructions of past centuries conventionally label their coldest interval as "LIA" and their warmest interval as the "MWP". Others follow the convention and when a significant climate event is found in the "LIA" or "MWP" time frames, associate their events to the period. Some "MWP" events are thus wet events or cold events, particularly in central Antarctica where climate patterns opposite to the North Atlantic area have been noticed.
Doesn't it describe how climate researchers associate events to the MWP? It seemed to fit right in as an intro to the various events. (SEWilco 21:02, 26 May 2005 (UTC))


  • Removing the words "IPCC" whilst linking to them is inexplicable.
You've said the researchers are important, not the IPCC. We often mention information and link to supporting material. (SEWilco 21:02, 26 May 2005 (UTC))

Rv: why

(William M. Connolley 21:00, 28 May 2005 (UTC)) I've restored the globality bit to the intro, since its obviously important: starting with Bradley and Jones, 1993 (or at least that the first easily findable one: it could well be earlier: if I wasn't wasting my time on this I could be looking it up...). SEWs moving of it (at least according to his most recent excuse) was the word "recently"; since that was my word, I've removed it, and bingo! Away goes his excuse, since Bradley and Jones, 1993 is clearly not "recent".

Ditto the Jones and Mann (2004) observation that people tend to call the coldest bit LIA and the warmest the MWP. This explains why MWP/LIA dates are so variable, and why people carelessly attribute famies to the LIA even when they fall within the MWP time period.


(William M. Connolley 18:53, 8 Jun 2005 (UTC)) JG wrote:

though not as extensively as during the MWP

for grape growing. The evidence - the links on the page - say otherwise:

At the time of the compilation of the Domesday Survey in the late eleventh century, vineyards were recorded in 46 places in southern England, from East Anglia through to modern-day Somerset. By the time King Henry VIIIth ascended the throne there were 139 sizeable vineyards in England and Wales - 11 of them owned by the Crown, 67 by noble families and 52 by the church.

whereas lists 400 current vineyards. Furthermore, Henry VIII was born in 1491 which is well out of the MWP. This is yet another example of adjusting the MWP/LIA evidence to fit preconceptions.

Rv'ing JG

JG removed:

although less extensively than they are today [16] (however, factors other than climate strongly influence the commercial success of vineyards; and the time of greatest extent of mediaeval vineyards falls outside the MWP)

with the bizarre comment Remove speculation and irrelevant/unsupported editorializing. The comment is supported; its not speculation. What it is is something that upsets JGs POV, and as a dedicated POV-pusher he doesn't like that.

He also removed: It has been argued a better name would be the Medieval Climatic Anomaly.. It would be more polite to inquire, on the talk page, if this can be supported, rather than implotely removing it. It can, of course, be supported [17].

Happily, it looks like JG is about to be banned soon [18] so we won't have to suffer him much longer.

What fresh nonsense is this? --JonGwynne 08:34, 26 Jun 2005 (UTC)
JG got a reference in Science? Well. (SEWilco 03:41, 26 Jun 2005 (UTC))
Oops, wrong ref, nonetheless he's been banned anyway. William M. Connolley 19:50, 26 Jun 2005 (UTC).

End of the MWP

Folks, I've changed mentions of the end of the MWP to be vague on dates, being no more specific than "14th century". This is because what year the MWP ended depends on what criteria you use to define it and where you're measuring; certainly it was still warm most places in 1270 and Northern Europe was in cold winters and short summers by 1350, but points anywhere in between are matters of scholarly opinion ... and the scholars don't agree. More discussion on the LIA discussion page. Jberkus 05:11, 11 September 2005 (UTC)

making wine vs. growing grapes in Alaska

Hi! In the 'Climate events/North Atlantic region' section of the article, there is this first sentence:

" During the MWP wine grapes were grown in Europe as far north as southern Britain[4][5][6] although less extensively than they are today[7] (however, factors other than climate strongly influence the commercial success of vineyards, for example wine is made in Alaska today; and the time of greatest extent of medieval vineyards falls outside the MWP). "

I would dispute the phrase, "..for example, wine is made in Alaska today.." since there are no grape vineyards in Alaska. Wine made in Alaska is made from many locally grown things including wild berries or dandelions, but any grape juice would have to be imported. The fact that wine is made in Alaska today doesn't have any bearing on the commercial success of vineyards, since there aren't any up here. Marty gla 23:11, 9 January 2007 (UTC)

The current global warming period

did not begin in the 19th century. From 1945-75 global temperature fell. So much so that scientists of that time were predicting a new Ice Age. I deleted a line to that effect. SmokeyTheCat 22:04, 13 March 2007 (UTC)

Box core

Could someone write a stub for box core and link to it? Thanks. —The preceding unsigned comment was added by (talk) 08:24, 8 April 2007 (UTC).

I have restored the external link questioning the basis of the hockey stick graph. Since it is in this article, then you need a counter-balance to keep the whole article NPOV, despite what Connolly thinks. I notice he refers to his own blog as a main ref in the Global warming articles. Peterlewis 16:10, 16 April 2007 (UTC)

Viking expansion and climate

Watching a program (Mega Disaster: Mega Freeze on the History Channel) that mentions the Medieval Warm Period and the Little Ice Age they point out the drastic effects on Viking civilization throughout Vineland, Greenland, and Iceland. Do you think such effects are worthy of mention here or should be regulated to the viking pages? --Wowaconia 07:15, 21 May 2007 (UTC)

That effect is usually overblown a bit - the Little Ice Age probably had an influence on the Viking colonies, but so had shifting politics and interests (with Norman England and the Crusades, the focus of European interest shifted from the North). We have a bit of information on this topic here, though not in encyclopedic form. It would certainly be interesting if we find some better sources than a TV program (and then one with a title that could be from Marvel Comics ;-). --Stephan Schulz 08:37, 21 May 2007 (UTC)
The Viking colonisation of Greenland and North America is well attested by archaeological evidence and the historic record of the Norse sagas. Warming of the climate allowed tree growth in Greenland, and crop growth to support the Vikings. Ice-free waters also led them to colonise Newfoundland and maybe further south in Vinland. Peterlewis 08:51, 12 July 2007 (UTC)

Unnecessary Reversions

I have just put back a website from the Universty of Southern California, which gives a fair summary of evidence without any politcal bias. If this is so old (and the refs do not support the assertion), why is it still extant? Is ths yet another example of plitical c ensorship by the global doomsters? I appreciate that they want to delete counter-evidence to their position, but Wiki must keep a NPOV. The Medeval warm phase is supported by a great deal of clear evidence. Anybody heard of George Orwell??? Peterlewis 15:15, 12 July 2007 (UTC)

The data on that website is older than 1990 - and none of the links on the page works. That indicates to me that this is an old artifact, which just hasn't been deleted. And if i check with google - only one page links to it: [19] and nothing links to that page [20]. So i'm deleting it again. --Kim D. Petersen 16:49, 12 July 2007 (UTC)
Please see WP:EL#Links normally to be avoided - point #1+2 --Kim D. Petersen 16:55, 12 July 2007 (UTC)
You should check your facts: the webpage is later than 2003 judging by the dates of papers and links etc. All the links work on my computer, so you should check your computer before rushing to delete good summaries. The wiki advice does of course not cover POV and bias by editors. Peterlewis 17:54, 12 July 2007 (UTC)
While some of it is newer than 1990 (although i didn't find anything older than 1999) - the links at the top of the page are completely dead (404 not found). And nothing still links to it.
The page is not acceptable - since the first 2-3 screen pages are so misleading as to even contradict the conclusions at the bottom of the page (). I don't know what the purpose of this page was - but i suspect that it was a lecture, where an oral explanation is supposed to be overlaid. The first graph on the page is from the first/second IPCC report - and is a sketch of how temperature variations during the last 1000 years was thought to be. It has been completely outdated with the various proxy reconstructions. --Kim D. Petersen 18:57, 12 July 2007 (UTC)


PW dislikes [21] although less extensively than they are today and uses as a source for this. But the map is clearly wrong; there are modern vineyards in Yorkshire [22]. Etc. William M. Connolley 13:04, 5 September 2007 (UTC)

WC has misinterpreted my edits as well as misspelling my initials. Cites are required for including stuff, not deleting false information. There are two errors. (a) "although less extensively than they are today[8]". Now, reading this, you might think that ref [8] would say that the medieval vineyards were less extensive than todays. But it says nothing of the sort. It says there are about 400 vineyards today. In fact there were about 1,300 vineyards in England in the 11th - 12th century (Oxford Companion to Wine). (b) The second error is "the time of greatest extent of medieval vineyards falls outside the MWP". Again the Oxford companion says the peak was 11th - 12th century, in the MWP. Paul Matthews 13:02, 6 September 2007 (UTC)
apologies for getting your initials wrong - corrected. But you said *extensive* - not *numerous*. Modern ones are clearly more extensive. You don't defned deleting "however, factors other than climate strongly influence the commercial success of vineyards" - do you accept that this should stay? As for the peak - will have to look at that William M. Connolley 13:56, 6 September 2007 (UTC)

Ok, I will stop calling you WC :). You still need to justify "modern ones are clearly more extensive" if you think that is true, which it isn't. There were medieval vineyards in Yorkshire too (same source). Selley didnt include these (ancient or modern) in his Winelands of Britain map - I guess his lines are an approximation omitting outliers. Regarding the peak, we have

  • The Oxford Companion which says the golden age was 11th-12th century
  • "The Doomsday Book of William the Conqueror records that at the end of the 11th century there were 28 producing vineyards in Norman England. These vineyards prospered over the next 300 years, and England developed into an important center of European winemaking."
  • "British wine-making thrived during the Medieval Warming, failed during the Little Ice Age (1300 to 1850), and began to make a comeback in the 1950s, after major world temperature surges between 1850-70 and 1920-40. The uncertain quality of today's British wine grapes indicates that Britain still isn't as warm now as during the Roman and Medieval Warmings."
  • "Although the Dissolution of the Monasteries in 1536 is often cited as being the single event that destroyed winegrowing and winemaking in England, it would appear that by this time, many monasteries had given up."

But it turns out that the "other factors" is partly true according to some sources that talk of alliances with France making it easier to get better wine from there! But Selley says the main factor was climate: "Had the decline in viticulture during the 15th - 19th centuries been due to factors other than climate then the geographic limits of viticulture should have remained unchanged. The restriction of vineyards to southeast England suggests that the ebb and flow of viticulture across Britain is climatically controlled." Paul Matthews 18:32, 6 September 2007 (UTC)

Can't say I like the current compromise, which probably means its fair. I'm sure I knew a good source for the "greatest extent" stuff but since I can't find it now I'll leave that. As to other factors: it seems pretty obvious that ability to ship the stuff to and fro would strongly affect whether you bothered grow it in situ or not. But without a good source I won't press that.
In fact that section is a bit weird: in that its headed Climatic events but then starts off with vineyards without any justication of their climate-relatedness William M. Connolley 20:21, 6 September 2007 (UTC)
So did the British start growing wine because the climate was so good, or because they had no source for the wine needed for the Eucharist? Lars T. (talk) 01:54, 23 February 2009 (UTC)

The current wording is not supported by the cites, so it will have to be more neutral. --Skyemoor 01:46, 14 September 2007 (UTC)

"climate events"

The "climate events" section appears to be overly anecdotal. Why mention 1 core from the sargasso sea, for example? There are lots of cores about.

Also "The Vikings took advantage of ice-free seas to colonize Greenland..." if true, the "climate event" is the ice-free sea. Is there any evidence for that (then link it). As it stands we have a societal event being used as a proxy of unknown value for a climate event William M. Connolley 08:25, 14 September 2007 (UTC)

Yes it needs a ref, also as you say the title 'climate events' is wrong. The section is really about evidence for the existence of the MWP, so I've changed the title. Also the previous section is poor - where is this 'initial research'? In other words, who claimed that the MWP was a global event? Paul Matthews 14:58, 14 September 2007 (UTC)
Sorry, but if you read the section, you will notice that it discusses a number of different indicators, several of which refute the idea of a global MWP. I'm reverting that part. --Stephan Schulz 15:07, 14 September 2007 (UTC)
Please be more constructive. We are supposed to be improving the article. As William points out above, the title 'climate events' makes non sense. It is more about proxy temperature indicators. If there are things that disagree with a global MWP they can go in the criticism section. And that section needs rewriting too - surely nobody, not even you and William, thinks the MWP didnt happen at all? The MWP shows up very clearly in the composite of graphs at the top of the page. Paul Matthews 17:19, 14 September 2007 (UTC)
The current consensus seems to be that the MWP was somewhat overrated as a single, global period. If you look at various proxies, many researchers label a MWP, but very often the time periods do not match. I do agree that there probably was mild overall warming, that was more extensive in the northern hemisphere, and that was quite variable in other parts of the world. We must find a way of clarifying that not every individual research paper finding an MWP signal is evidence for a strong, global MWP. --Stephan Schulz 17:57, 14 September 2007 (UTC)
Yes I know all this. But the article says it never took place according NOAA, which is just stupid. I have changed that. I tried to change the stupid title 'criticism' as well (criticism of what?) but that just got reverted. Paul Matthews 16:38, 17 September 2007 (UTC)
Now Skyemoor has reinserted the false statement that the NOAA say there is no evidence the MWP took place. Paul Matthews 13:53, 19 September 2007 (UTC)
From the reference [23]:
The idea of a global or hemispheric "Medieval Warm Period" that was warmer than today however, has turned out to be incorrect.
So its not a "false statement". --Kim D. Petersen 15:00, 19 September 2007 (UTC)
I don't much like that section and am in sympathy with PM. Firstly, its not NOAA research (at least the ref isn't) isn't just a general exposition for the public. Second the grammar of the sentence in question is poor. And as PM points out the title is odd. I would suggest merging that section into the intro (the ref there would satisfy the cn in the intro) William M. Connolley 15:07, 19 September 2007 (UTC)
I agree that the wording/grammar is dicey. And have no opinion on the section title or where it should be. --Kim D. Petersen 15:14, 19 September 2007 (UTC)

Energy and Environment

On what basis do certain editors contend that this is an unreliable source? Iceage77 (talk) 23:07, 19 November 2007 (UTC)

On the basis that it is not in any recognized science citation index, in extremely few libraries, and that it has been criticized as unreliable even by some of its own authors, and is, in general, crap. See Energy and Environment for some of the gory details. --Stephan Schulz (talk) 23:12, 19 November 2007 (UTC)
So papers which cast doubt on AGW are rejected by "mainstream" journals, forced to publish in E & E, then dismissed on the basis of a rather thin ad hominem argument. Given the obvious censorship inherent in this process, it's hardly surprising that so many are sceptical of the "consensus". Iceage77 (talk) 23:40, 19 November 2007 (UTC)
Getting a paper rejected is normal - most top journals publish less than 10% of submitted papers. And the criterion is the quality and significance of the work - which gives papers deviating from the mainstream a bonus. Nobody is forced to publish in E&E, and an E&E paper has no value even by publish or perish criteria. --Stephan Schulz (talk) 23:48, 19 November 2007 (UTC)
None of Stephans argument was ad hom William M. Connolley (talk) 23:52, 19 November 2007 (UTC)
Of course it is. If it's published in E & E, it has no value. This is the very definition of ad hom. Proper scientific criticism is going on at CA [24]. Iceage77 (talk) 00:10, 20 November 2007 (UTC)
But Stephan didn't say If it's published in E & E, it has no value. He said On the basis that it is not in any recognized science citation index... and various other things that you could have read yourself had you bothered to. What is the point in asking questions if you won't bother read the answers? William M. Connolley (talk) 09:29, 20 November 2007 (UTC)
Stephan clearly said "an E&E paper has no value" so it's you that is not reading the answers. The fact remains that this paper meets all the requirements of WP:V. Iceage77 (talk) 11:15, 20 November 2007 (UTC)
Oh dear William M. Connolley (talk) 12:00, 20 November 2007 (UTC)
Iceage, the paper has no value as a CV item for the purposes of tenure and other academic credentials. I am not familiar with this journal but in the areas that I do research (not climate related at all), there are numerous journals that allow publishing of ideas and research results that are not reviewed. This is extremely useful for inventions that the inventor does not want patented, nor does he think it will pass review (or maybe it's not significant enough for more substantial publication). The author can then publish in these journals to record it as "previously published" in case someone down the road tries to use the same invention. There are no standards for inclusion. --DHeyward (talk) 15:35, 20 November 2007 (UTC)
That said, is the author of the piece an expert in this field? Wikipedia has been using blogs as reliable sources for climate so I don't see how this is any different. The author is named so it might be inclusionable on that basis. --DHeyward (talk) 15:35, 20 November 2007 (UTC)
E&E has a nominal review process, however, it has an academic reputation as being extremely lax and lop-sided in handling it. Also, the editor in chief is quite open in saying that she publishes papers to suit her own political agenda ("I'm following my political agenda -- a bit, anyway. But isn't that the right of the editor?" [25]). I don't know if that is an acceptable standard in the social sciences, but it is not in the natural sciences. Of course, that does not imply that the paper is necessarily bad, but it implies that it is not published in a WP:RS. Loehle's paper has previously been rejected from GRL ([26], comment 6), so that's an independent reason to be skeptical. --Stephan Schulz (talk) 17:41, 20 November 2007 (UTC)
We accept non-reviewed blogs as reliable sources if the blogs are by experts. Non-reviewed blogs are even less reliable than rejected papers or papers accepted to marginal journals. The only question is whether the author is an expert. I don't mind upping the standard of reliable sources, but that would mean that web sites such as would not qualify as a reliable source. I don't think anyone wants to do that so the standard for this source (which is the author Loehle) is the same as the standard for which is the author is an expert. --DHeyward (talk) 20:41, 20 November 2007 (UTC)
I agree in part. A WP:SPS can be reliable if the author is a recognized expert writing in his field of expertise. A rejected paper, however, is not more reliable than a blog - rejection does not necessarily mean a paper is bad, but it certainly does not confer any extra authority to the paper. So it boils down to the question wether Craig Loehle is a reliable expert. --Stephan Schulz (talk) 21:04, 20 November 2007 (UTC)
I agree that the question is whether Loehle is a reliable expert. However I would twist your statement around: I would not convey any more authority to a blog, which has not been submitted for anything, than a "rejected" paper. For example, if Loehle is an expert and he chose to self-publish his results on his blog, rather than submit it for peer review, it wouldn't have more authority because it hasn't been rejected. He's either an expert and cited as such or he's not, but if we are going to allow WP:SPS sources, it's the whole Faustian bargain and published papers by experts, whether self-published or not, are citable. --DHeyward (talk) 22:26, 20 November 2007 (UTC)
I couldn't find a CV for Loehle on the web so it's hard to say. As best I can tell, he is a mathematical ecologist who only recently begun working in paleoclimate and reconstructions. He's published a couple of papers on that general topic but isn't nearly of the same prominence as RealClimate contributors such as Gavin Schmidt, Michael Mann, Ray Pierrehumbert, and Stefan Rahmstorf who are widely recognized as leading scientists in their fields. Raymond Arritt (talk) 22:44, 20 November 2007 (UTC)

Iceage77 wrote:

So papers which cast doubt on AGW are rejected by "mainstream" journals, forced to publish in E & E, then dismissed on the basis of a rather thin ad hominem argument. Given the obvious censorship inherent in this process, it's hardly surprising that so many are sceptical of the "consensus".

Are papers being rejected unfairly because they reach conclusions that deviate from what most scientists assume is true and not because of bad science? Are there any sources that make this case? If so, then that would be a topic for the global warming controversy page.

But I'm very skeptical of this because then you would expect that many scientists would complain about that. It is quite common for authors of unfairly rejected papers to vent their anger on their homepage or in updated preprints, see e.g. here, or here (page 3 and further). Count Iblis (talk) 18:37, 22 November 2007 (UTC)

I'm a skeptic and I view E&E as crap. It is not held by standard grad school libraries. It does not have good peer review. And some of the articles, regardless even of skeptic versus believer are just poor quality in terms of footnotes, style, care taken in reading literature, etc. There are so, so, so MANY normal journals, that anyone who wants to write controversial (well done) analyses can get them published in the real literature. E&E is for lazy slackers. —Preceding unsigned comment added by (talk) 20:46, 26 March 2008 (UTC)

What is the NOAA?

It is referred to in section one but not identified. SmokeyTheCat  •TALK• 10:31, 22 November 2007 (UTC)

Typing it into the search box would have lead you to our article on the National Oceanic and Atmospheric Administration. I've included the link. --Stephan Schulz (talk) 19:56, 22 November 2007 (UTC)

MWP is understated

The IPCC has a vested interest in understating the MWP as it is involved in it's usual scaremongering but the truth is that grapes were grown in many places in Southern England ( it's too cold for that now ) and Greenland was green (hence the name) ie. arable land wheras now it's covered in an ice sheet. So it stands to reason that it was much warmer than it is now. During this long warm period London wasn't flooded, the North Polar ice-cap didn't melt nor did polar bears become extinct.  SmokeyTheCat  •TALK• 10:31, 22 November 2007 (UTC)

  • I don't know where your opinion about the IPCC comes from, but it is not shared by the scientific community, which has repeatedly lauded its work in formal statements by many of its most prestigious institutions. See scientific opinion on climate change.
  • Wine is now grown in England farther north than ever in recorded history, including the MWP. However, wine growing is heavily influenced by cultural influences (e.g. the demand for mess wine for Christian ceremonies) and economic realities (both easy access to foreign wine and EU subventions), and is hence a lousy climate proxy.
  • Greenland (a propaganda term invented by Eric the Red) is still green in all the same places.
--Stephan Schulz (talk) 10:57, 22 November 2007 (UTC)
I cannot believe that Stephan is still trying to spread this false information about English wine. As discussed at length by me above, there is plenty of data showing far more vineyards in medieval times than now, and just as far north (and that is despite improved grape varieties and farming methods). Furthermore there is evidence from Selley's work ( that the decline was climatic. Paul Matthews (talk) 14:43, 22 November 2007 (UTC)
I don't think your sources are particularly reliable. But lets see if we can find some common ground here. Do you agree that a) wine is grown "in many locations ins Southern England" today (i.e. it's not "to cold for it now") and b) than the extend of wine growing depends on many things in addition to climate and that it hence is a lousy climate proxy? --Stephan Schulz (talk) 14:53, 22 November 2007 (UTC)
You dont think the Oxford companion to wine is a reliable source? What is your source for "Wine is now grown in England farther north than ever in recorded history"? (a) Yes, reasonable wine is grown in southern England and a small amount of lousy wine is even produced in the middle and north of England (b) Yes, there are other factors, as discussed above, but I wouldnt say it was a lousy proxy - its still better than tree-rings :) Paul Matthews (talk) 14:22, 23 November 2007 (UTC)
OK, good - we're agreed STC is wrong about grapes. I would argue that he is also wrong about Greenland William M. Connolley (talk) 14:39, 23 November 2007 (UTC)
I would think that the "Oxford Companion to Wine" is a reasonably good popular book on wine. I don't think that it is a reliable source on the exact details of medieval English viticulture, no. I don't think it claims to be, and I would suggest that a poetic term like "golden age" is open to serious interpretation - does it refer to quality, quantity, spread, market share (compared to imported wine), market share (compared to competing drinks like beer), tax revenue, or a mixture of those and/or other factors? --Stephan Schulz (talk) 14:47, 23 November 2007 (UTC)
You obviously havent read it and so have no idea what you are talking about - it's a serious volume not a popular book, with further references. And you still havent given a reference for your false "ever in recorded history" remark, where did that come from? It sounds worthy of Mann! But all this is not really relevant to any changes in the article. Paul Matthews 18:06, 4 December 2007 (UTC)
Believe the fashionable hysteria about human-caused global warming if you choose. No-one has refuted the three points I made at the beginning of this section.  SmokeyTheCat  •TALK• 18:18, 18 July 2008 (UTC)
I am a layman, and the quote in the article essentially says that the IPCC has effective dismissed the Little Ice Age and the Medieval Warm Period as local rather than global; it also states that the records obtained from tree rings, ice cores and lake deposits show that the temperature in those times was colder. Now, are these samples uniformly distributed over the globe? One cannot have ice cores from the tropics, and the tropical forests are prone to deforestation so that 1000-year-old trees are not numerous; hence, such records will be necessarily more from the colder regions, and will produce a skewed result. I am eager to know how IPCC handled this issue and arrived at its conclusion. Gopalan evr (talk) 03:50, 14 September 2008 (UTC)
I'd be surprised if the IPCC report doesn't have a pic of where the proxies are. You are correct that they are very uneven; there are (I think) no tropical tree rings, but thats because tropical trees don't do rings, not because of deforestatin William M. Connolley (talk) 20:37, 14 September 2008 (UTC)

I've got a refference for it being world-wide

but i don't know how to do i citation. The reference is Can someone add it for me, tell me how to do citations, or tell me where i can learn how to do them? (talk) 08:59, 11 May 2008 (UTC)

LaRouche movement publications are unreliable sources per arbcom. --Kim D. Petersen (talk) 09:41, 11 May 2008 (UTC)

I think the article contridicts itself, it says evidence has showen the warm period to be only in Europe and then mentions drought in California & Africa as well as warmer tempreture in Japan, and also Vikings taking advantage of the warmer weatehr to populate Vinland and Russia? Is there anywhere in the northern hemisphere left??! Perhaps it was a northern hemisphere warm period. According to this article the only place where there is evidence the warm period did not occur is antartica, yet the article states that the warm period is believed to be isolated to Europe. Strange —Preceding unsigned comment added by (talk) 08:27, 15 May 2008 (UTC)


The article says that NOAA pooh-poohs the idea of a MWP: "(NOAA) states that the "idea of a global or hemispheric 'Medieval Warm Period' that was warmer than today however, has turned out to be incorrect".
But over at UCAR (which ought to be at least as likely to know), as of 2007 ( the The Medieval Warm Period (950-1100 AD) still exists.
Do I smell the stench of politics in this science article?
Consider further that the "Mayan Collapse" happened at the same time as MWP, and that the MC has been recently attributed to drought. Anyone out there still objective enough to fix these discrepencies? Twang (talk) 21:14, 22 June 2008 (UTC)

Well, from that very page you link to: "The Medieval Warm Period was a time of warm climate in Europe" (emphasis mine). I'm not particularly familiar with Mayan history, but according to our article on the Classic Maya collapse, droughts in Yucatan coincide with cold temperatures in Europe. Also, the collapse was more or less complete the end of the 9th century, i.e. before the MWP starts. --Stephan Schulz (talk) 21:41, 22 June 2008 (UTC)

I think inserting black line representing instrumental measurements into the spaghetti graph of reconstructions is highly misleading, because there is a divergence between the two - almost all proxy reconstructions show cooling or flat trend for last 30 years while temperature measurements show warming. The reason for this discrepancy is not clear, but you cannot have it both ways: either you believe instrumental record in which case you cannot mix it with proxy reconstructions, or you believe reconstructions, in which case you must reconsider instrumental data. Instead this apples and oranges mixture, you should use proxy data until 2008. If you don't have proxy updates since 1980 (as most of reconstructions do not have them) you should remove misleading instrumental graph. The only purpose of that graph is to strengthen impression of "unprecedented" warming in XX century. Once you remove it and insert only proxy data to make apples to apples "spaghetti", that impression dramatically weakens. IPCC uses trick with inserting instrumental data as propagandistic tool. Wikipedia should have NPOV.

Apart from that you should include in the spaghetti new reconstruction by Leohle (2007).--Ivanorte (talk) 18:02, 24 July 2008 (UTC)

Its being done this way, because thats the way reliable sources do it. For instance the NAS and the IPCC (as well as several science papers). Your assertions of the IPCC using "tricks" certainly do not give an impression of NPOV btw. --Kim D. Petersen (talk) 12:19, 25 July 2008 (UTC)

Link to Loehle reconstruction is here: Article is published in journal Energy and Environment. Please correct spaghetti graph by including Loehle reconstruction. --Ivanorte (talk) 08:46, 25 July 2008 (UTC)

Energy and Environment is not a reliable source. See many other discussions, as well as the E&E article itself. --Kim D. Petersen (talk) 12:17, 25 July 2008 (UTC)

But, Real Climate blog is reliable source?!--Ivanorte (talk) 17:58, 28 July 2008 (UTC) How did you explain mixing apples and oranges, proxy reconstructions with instruemntal measurements to strenghten impression of "unprecedented warming" but as a trick? IPCC is not neutral, honest or reliable source of information, even less practices (see eg. hockey stick fiasco, lead author of paleo working group promoting his own flawed study), so reffering to them as a precedent is weak argument. But, apart from that what is justification for inserting instrumental graph? If we take into account divergence problem, that inserting is pretty misleading.--Ivanorte (talk) 18:12, 28 July 2008 (UTC)

"Unusually" Warm Climate

The lede uses the term "unusually", though there is no basis or context for this term ("unusual" compared to what?). Please provide basis or it will be removed. --Skyemoor (talk) 18:17, 3 October 2008 (UTC)

Geographical extent

Why does the intro say that MWP was only "in the North Atlantic region," while further down it mentions Antarctic ice cores? Is it:

  • clearly only in Europe or North Atlantic; or,
  • asserted by some scientists to be only in Europe or North Atlantic, while other scientists (in peer-reviewed scientific journals) say the opposite; or,
  • clearly worldwide

Is there is scientific debate about the extent? If so, shouldn't we describe the debate? And indicate its existence?

Is there no scientific debate? If there is none, should we mention non-scientific debate? Who's debating this, if it's not scientists? --Uncle Ed (talk) 17:18, 11 December 2008 (UTC)

Take a look at the references called out in the article, for example;
--Skyemoor (talk) 18:19, 11 December 2008 (UTC)

Why were references to 5 scientific publications cut out of this section? Greyweather (talk) 10:12, 19 June 2009 (UTC)

Diff? William M. Connolley (talk) 10:26, 19 June 2009 (UTC)
The ones you cut out on June 11th. What made you remove them but not the other entries in this section? Greyweather (talk) 02:30, 20 June 2009 (UTC)

Bad refernces....

I don't see how wiki can cite the NOAA website opinion piece on MWP when it is neither endorsed by NOAA (see the disclaimer) not give scientific justification for its conclusions. Especially at such length and with an unidentified author. This is surely heresay? (talk) 16:52, 12 March 2009 (UTC)

Of course it is "endorsed by NOAA" - they wrote it. The disclaimer refers to "links to web pages which are not part of the NCDC web family". And the authors are, of course, given in painstaking detail at [27]. --Stephan Schulz (talk) 17:27, 12 March 2009 (UTC)

NewScientist: "Natural mechanism for medieval warming discovered"

From NewScientist: "Natural mechanism for medieval warming discovered". (02 April 2009).

This appears significant and important new research on the so-called "MWP".. I'd try adding to the article, but probably someone who is better versed in the science could do a better job. Green Cardamom (talk) 00:33, 4 April 2009 (UTC)


[28] is probably meaningless without knowing what they mean by CWP William M. Connolley (talk) 15:01, 11 June 2009 (UTC)

A better graph

Would anyone mind if I replaced the misleading temperature graph with have at present with this more accurate one?

File:Whatwarming.jpg (Source IPCC 1990)

 SmokeyTheCat  •TALK• 00:15, 3 March 2009 (UTC)

Question: WhatFile.txt? --Stephan Schulz (talk) 00:18, 3 March 2009 (UTC)
Sorry I was just uploading it.  SmokeyTheCat  •TALK• 00:20, 3 March 2009 (UTC)
Yes, I would mind if you replace a large ensemble of recent climate reconstructions with a 20 year old schematic with unclear copyright status. --Stephan Schulz (talk) 00:26, 3 March 2009 (UTC)
....which represents Central England temperatures[29][30] - and not global.... --Kim D. Petersen (talk) 02:08, 3 March 2009 (UTC)
Well I won't cause a fuss. England is not in a climate bubble so it seems a fair sample. Anyway, I don't have an axe to grind. If we're all still here in 20 years time all the present global warming hysteria will be long forgotten and laughed at, just as we laugh at the predictions of a new ice age which were all the rage in the 1970s. It's no skin off my nose. Having just endured the coldest Winter in 20 years the whole thesis is looking distinctly pear-shaped now. SmokeyTheCat  •TALK• 11:20, 3 March 2009 (UTC)
Thanks for this opinion. It displays very well just how deep your understanding of the domain is. --Stephan Schulz (talk) 11:55, 3 March 2009 (UTC)

The graph at the beginning of this article should be removed as the black hockey stick line ending with the astrix 2004 clearly represents the totaly discredited Yamal treemometer. As per Steve McIntyre Sun Spot —Preceding unsigned comment added by (talk) 02:57, 21 October 2009 (UTC)

Cold climate grapes

I'm sorry - but the reference doesn't state that Sweden only produces cold climate grapes, quite the opposite in fact - it states that most (ie. not all) are cold-climate grapes. And the 50° is for cold-climate grapes. The text inserted is complete original research. --Kim D. Petersen (talk) 20:09, 20 May 2009 (UTC)

Add: The new insertion about whether its climate or because of the grapes, jumps to conclusions not supported in the reference. (just an addition here to the above: Riesling is one of the cold-climate grape that the article is talking about, and that is the grape that is recommended up to 50°) --Kim D. Petersen (talk) 20:11, 20 May 2009 (UTC)
The vinyard from which the photo's in the article comes, Wannborg Vingård.[31] Produces amongst other grapes Rondo, Léon Millot, Regent, Solaris, Orion. As well as Merlot, Pinot Noir and Chardonnay, all of which aren't exactly "cold climate grapes". So can we stop this WP:OR now?

--Kim D. Petersen (talk) 20:24, 20 May 2009 (UTC)

I checked your source, you missed some important information. They grow only the hardiest cold climate grapes, but have, in the past, experimented with other cold climate grapes (yes they are [32] - just less hardy varieties) like Merlot, Pinot Noir, Chardonnay, Riesling etc. (talk) 11:21, 21 May 2009 (UTC)
One of very few commercial Wine Yards in this northern region. We are experimenting with nearly 40 different kinds of grapes to find out who are best suited for our cold climate. Our main species are Rondo, Leon Millot, Regent, Solaris, Orion. But we also grew some well known grapes with good result as Merlot, Pinot Noir, Chardonnay, Riesling etc.
For those still sceptical - please check the memberlist of the Svenska Vinodlara [33] (Swedish Viticulture) - for most members the grapes produced, and the area cultivated, is listed. Riesling, Merlot, Chardonney etc. are all amongst them. --Kim D. Petersen (talk) 20:30, 20 May 2009 (UTC)

Sorry, I edited the article before checking here first. But I think the whole section on the Gotland grape should be removed, as it is misleading. Grapes have been grown in Britain also for many years, but Britain, nor Gotland, is a "wine growing region". There were vinyards in Britain in the 18th and 19th century. The problem is that the climate was not suitable for good wine, not that you can't grow grapes there.

The section on Gotland should probably be removed, as it is misleading and doesn't really make a point. The northernmost wine growing region is widely considered to be northern Germany, not Sweden. This might change with the climate, and if you can find an article that states the climate might alter this that fact then great, but it currently doesn't include Gotland. Antistar (talk) 22:16, 20 May 2009 (UTC)

This is not correct. Ireland, United Kingdom, Belgium, Poland, the Netherlands, Denmark and Sweden have been in the EU wine-growing region A (c), at least since in 2000[34][35], and thus can (and do) produce commercial wines at least from that time on (Denmark was added in 2000). They btw. all produce good wine. Denmark (my region) has a marginal production - but it still manages to produce international winning wines [36], as does the UK. --Kim D. Petersen (talk) 23:12, 20 May 2009 (UTC)
I'll btw. be adding some of these references, but will not right now - since i'm at 3RR. Btw. strangely enough you missed the english-wine growing reference in the article - England produces quite a lot of good wine... --Kim D. Petersen (talk) 23:16, 20 May 2009 (UTC)

Maybe you should slow down and read before rushing to "correct" me. How could I "miss" the English wine growing reference, when I write "grapes have been grown in Britain also for many years". If you slow down and try to understand what I am writing, you will realise that I accept that wine grapes are grown in many regions north of Germany, but nowhere north of the 50 is considered a "wine growing region". This is because the vineyards may be able to succeed there, but the produce is not considered good enough quality and/or the risk of a killer winter is too high to make them a reliable region.

Climate change is obviously making some regions more capable of growing good, reliable crops, but so are hardier "cold climate" hybrids, soil technology, etc. Seriously you can't be thinking that climate change alone could have shifted the latitudinal limit as much as 7 degrees north already?

For whatever reasons, be it climate, necessity, whimsy or what have you, Britain was a relatively significant wine producer in the 14th century. Today it is so minor that it isn't even considered to be a wine producing region (yes the EU recognises that it has vineyards, but the EU would recognise any region that produces one bottle because it has to).

The latitudinal limit is considered to be 50, and this is a well known fact (it is even stated as such in the Gotland article). Even if that is changing, or has changed, in recent years, the fact is that for many centuries it has been considered to be 50, yet in the 14th century Britain (which is beyond this limit) was a significant wine producing region. That is evidence, although not conclusive, that the climate in the 14th century was at least warmer than it has been until recently. (talk) 11:08, 21 May 2009 (UTC)

but nowhere north of the 50 is considered a "wine growing region" - by you, perhaps. yet in the 14th century Britain (which is beyond this limit) was a significant wine producing region - for the obvious reason: production was marginal, but viable because of transport difficulties. It doesn't provide any meaningful climate information. Comparison of your arbitrary 50 limit with the 14C is meaningless William M. Connolley (talk) 11:12, 21 May 2009 (UTC)
Maybe that is true, do you have a source for your claim? I know that before the 14th century there were contracts made for hundreds of thousands of liters of wine to be delivered to London, so I can't imagine transport was that difficult. Sometimes war with France would cause problems, but there were other regions to import from, and intermediate traders like the Dutch to buy from.
BTW, it's not "my" limit, it is one that is accepted as fact by vitners globally. This fact is not from my head, but even stated in the original linked article. I can find many, many more articles which back this up. Given its wide acceptance, it's hardly "meaningless", as this is a guideline developed over centuries of wine growing. (talk) 11:27, 21 May 2009 (UTC)
Well, the reading part is mutual it seems. "nowhere north of the 50 is considered a "wine growing region" is contradicted by the references (see EU wine regions), as well as reality 5 of Germany's 13 wine regions lie above 50° (Ahr (wine region),Mittelrhein (wine region),Rheingau (wine region),Saale-Unstrut,Saxony (wine region)) and you counter that by "but the EU would recognise any region that produces one bottle because it has to" is 100% incorrect, if you had read the references posted here, you would have noticed that (amongst others) Denmark had lobbied for more than 10 years to be allowed to produce commercial wines, if finally got that acceptance in 2000, the EU doesn't have to do anything (thats yet more WP:OR).
Your comments on quality and that it should be based only on hybrids is (again) contradicted by the references. As far as i can see the whole of EU wine growing zone A should not be able to produce wine then.
Finally when you are saying "considered a "wine growing region", "good enough quality" and "reliable", you should establish that England in the MWP adhered to these descriptions - can you do that? Otherwise the argument is moot, since the context here is "During the MWP wine grapes were grown in Europe as far north as southern Britain" not "During the MWP reliable good quality wines where produced as far north, as in the then well known and recognized wine region of Southern Britain". --Kim D. Petersen (talk) 12:14, 21 May 2009 (UTC)

I find it amusing and disturbing that I receive an edit war warning when I simply restored comments that someone removed without reason. The entire section on growing grapes in Gotland is questionable at best in an article on the Medieval Warming Period. The cited reference is poor, it's a news report on people growing grapes in Sweden. It is not a scientific report making any commentary on the relative warmth of the region today vs. the past. Attempts to do original research and suggest that the existence of vineyards in Sweden "proves" something about climate change is against wiki policy. I think most would have no objection to a statement that some grapes are now being grown in Sweden but whether this is because of stronger efforts being made to grow wine in a non-traditional region or because of a warming in the region is unknown. It is NOT known according to the cited reference and to suggest otherwise is against wiki policy on no original research, to remove an edit that says it is not known is vandalism or pov. Either the section should be removed entirely or it should be stated in an npov way. The original reference is a freelance writer's story on growing wine in Sweden and drawing conclusions one way or another from it in an article on the Medieval Warming Period seems unlikely to satisfy policy on quality. BobKawanaka (talk) 13:28, 21 May 2009 (UTC)

Thats rather a lot of strawmen: A) No one here is trying to prove anything. Its a simple comparison. MWP: Wine England Now: Wine: England+other places. B) "Traditional" is irrelevant here - England then wasn't "traditional" either. C) Noone is trying to say anything other than that vinyards now exist as northernly as Sweden. --Kim D. Petersen (talk) 13:35, 21 May 2009 (UTC)
I find it hilarious that you think that "The entire section on growing grapes in Gotland is questionable at best" but that of growing grapes in Britain is not. Obviously grapes are a poor indicator of climate, and the whole section should be thrown out as off-topic OR. Lars T. (talk) 21:04, 21 May 2009 (UTC)
See: google search on "Viticulture as a climate proxy. The reason for the interest in England, the MWP and wine, is (iirc) H.H. Lamb and the temperature reconstruction of Central England. (as well as several sceptics using the argument "England used to grow wine - now it can't" --Kim D. Petersen (talk) 21:52, 21 May 2009 (UTC)
See Werder, Brandenburg#Viticulture — Sorry, but when you can grow wine near Berlin during the "Little Ice Age", growing of grapes (without any information on quality) is a useless climate proxy. Time to tell us about the actual wines. Lars T. (talk) 00:55, 22 May 2009 (UTC)
Not really. The trouble with the comments so far, is that the poster has taken the 50° argument as valid (and more than a guide), the more "real" limit is the 12°C-22°C (±) growing season isotherm (which is more important than the annual average temp.). Viticulture is limited by more than just latitude - soil, mesoclimate and of course grape are all important. What you've noticed here would be a good proxy (if they have good records of harvests) to climate in Werder. --Kim D. Petersen (talk) 01:07, 22 May 2009 (UTC)
London#Climate vs. Berlin#Climate — Southern Britain should be better suited to grow wine than Brandenburg. And why exactly do you want detailed harvest records of Werder when all we know that during the MWP "wine was grown as far north as southern Britain"? Lars T. (talk) 19:19, 23 May 2009 (UTC)

In order for this comparison to be meaningful in this context, we need to have references which show not only A) that grapes are now grown as far north as Gotland and northern Britain but also B) that it was not possible to grow grapes in these places during the MWP. My understanding is that it was historically possible to grow grapes in Sweden, but it was not economic to do so versus importing products from France and elsewhere. Happy to be corrected, but for the moment the grape thing is unverified content and thus doesn't belong here. Gnomatic (talk) 09:10, 10 October 2009 (UTC)

I think you miss the point. The argument was never "its warmer today, look how far north we can grow grapes", it always was "wine is a lousy climate proxy, and growing grapes in Yorkshire does not tell us anything useful about temperatures". I'm fine with the whole paragraph gone. --Stephan Schulz (talk) 10:28, 10 October 2009 (UTC)

Medieval warming Graph

The graph is a compilation of a number of datasets around a mean. What mean was used for each of the data sets? Are the means different for each dataset? Since these are comparative, the mean (and offsets of each dataset) is somewhat important for a relative comparison. I didn't see a citation for the methodology of the overlay. --DHeyward (talk) 23:03, 20 November 2007 (UTC)

According to Robert's page, "each reconstruction was adjusted so that its mean matched the mean of the instrumental record during the period of overlap." Raymond Arritt (talk) 23:10, 20 November 2007 (UTC)
Get an up to date graph, this hockey stick stuck in 2004 is ridiculous and an embarrassment to wikipedia. Don't you wiki censors know how ludicrous this graph is ? —Preceding unsigned comment added by (talk) 03:27, 29 October 2009 (UTC)

Reconstruct Temperature, Graph

The graph at the beginning of this article should be removed as the black hockey stick line ending with the astrix 2004 clearly represents the totaly discredited Yamal treemometer. As per Steve McIntyre Sun Spot —Preceding unsigned comment added by (talk) 02:46, 21 October 2009 (UTC)

If you perform the distinctly tricky procedure of clicking on the graph and reading the caption - hard, I know - you can discover that the black line is the instrumental data. It seems that you are "lacking in clue" William M. Connolley (talk) 07:19, 21 October 2009 (UTC)
Yes, not the place for a protracted discussion. But something has always bothered me about that graph and that's the statement "The single, unsmoothed annual value for 2004 is also shown for comparison" ... it would be better not to include an unsmoothed point (from 5 years ago) and even it is included "for comparison" it should not be connected by black line to the rest of the series. It should be a single point. I don't believe I've read the caption incorrectly. HarmonicSeries (talk) 14:55, 21 October 2009 (UTC)
Get an up to date graph, this hockey stick stuck in 2004 is ridiculous and an embarrassment to wikipedia. Don't you wiki censors know how ludicrous this graph is ? —Preceding unsigned comment added by (talk) 03:22, 29 October 2009 (UTC)
Actually, it's stuck in 2000 or earlier for most of the reconstructions. The instrumental temperature record is updated frequently, but, as you might have notices, this article is about the middle ages. Has someone invented a time machine and gone back to change the climate in 1231? --Stephan Schulz (talk) 09:13, 29 October 2009 (UTC)

Scientists told to keep quiet about the Medieval Warm Period

Next, the UN abolished the medieval warm period (the global warming at the end of the First Millennium AD). In 1995, David Deming, a geoscientist at the University of Oklahoma, had written an article reconstructing 150 years of North American temperatures from borehole data. He later wrote: "With the publication of the article in Science, I gained significant credibility in the community of scientists working on climate change. They thought I was one of them, someone who would pervert science in the service of social and political causes. One of them let his guard down. A major person working in the area of climate change and global warming sent me an astonishing email that said: 'We have to get rid of the Medieval Warm Period.' "

Mixino1 13:33, 26 January 2007 (UTC)

You should know better than to trust stuff in the telegraph. But you may want to read MWP and LIA in IPCC reports William M. Connolley 11:36, 28 January 2007 (UTC)
You mean the same IPCC that 'got rid' of the Medieval Warm Period? As Professor Edward Wegman puts it "the work has been sufficiently politicized that this community can hardly reassess their public positions without losing credibility." Mixino1 16:40, 29 January 2007 (UTC)
Sorry - I've corrected the redlink. You might try reading it, if you're interested in the subject. There is no quesstion of "trusting" the IPCC in this respect - just finding out what happened. And as for Wegman - why do you think he is unbiased? William M. Connolley 17:54, 29 January 2007 (UTC)
I do not believe Wegman to be biased. Why should he be? Everything he stated was verifiably correct and sound statistical commentary. I can tell that in a professional capacity.
I actually fully believed the anthropogenic global warming claims until I looked at the evidence myself. I was honestly shocked to the core when I began to look at the evidence. Mann et al is a lowpoint in science. Even if you take Mann's work out of the equation now, it is clear that all graphs and models are designed to replicate the hockey stick. The damage is done.
Look at the history of Greenland. People lived and farmed there in the Medieval Warm Period. They could not have done that if it was colder than it is now. Despite this, climate scientists continue to only believe the graphs that show that it was colder than now. That belief goes against common sense.
To be honest, I am not sure if you actually believe what you are saying. Mixino1 19:01, 29 January 2007 (UTC)
I don't know if you believe what you're saying. Why should Wegman be biased? Because he was selected by Inhofe, perhaps? You won't attempt to assert that Inhofe is unbiased, will you? If your problems are with the statistics of MBH, then feel free to trow that study away and only use the other ones which show... pretty well exactly the same during the MWP (though they differ during the LIA). As fr Greenland... you are aware that these records are not just for Greenland, but for the whole hemisphere. A warm Gr and cool elsewhere is perfectly possible. —The preceding unsigned comment was added by William M. Connolley (talkcontribs) 19:29, 29 January 2007 (UTC).
Sorry, forgetting to sign. Anyway, we started with the Torygraph piece. Which contains The UN's second assessment report, in 1996, showed a 1,000-year graph demonstrating that temperature in the Middle Ages was warmer than today. This is false, and is why I referred you to MWP and LIA in IPCC reports which demonstrates that falsehood. Are you, I wonder, prepared to admit that the Telegraph is wrong in this? William M. Connolley 19:32, 29 January 2007 (UTC)
Here is what he said: "The graph from the 1996 UN report is not available online. I found it in a document from Professor McKitrick, one of the two Canadian scientists who first exposed the falsity of the graph." Mixino1 22:43, 29 January 2007 (UTC)

Sigh. I buess you're not going to read that page, no matter how much it explains your confusion. Hey ho William M. Connolley 22:48, 29 January 2007 (UTC)

You say Wegman is biased but you have produced no evidence that he is other than he was selected by some politician that might be. Has it never crossed your mind that McKitrick and McIntyre had actually discredited the piece anyway - and that any statistician would have said the same as Wegman unless he/she was extremely biased? By the time Wegman was involved, the errors were known and the (mis)calculations had been verified over and over. It seems more bizarre to me that Wegman even had to be involved given the wealth of information supplied by McKitrick and McIntyre that confirmed that the methodology was flawed. Mixino1 02:45, 30 January 2007 (UTC)
I'm confused as to why the two of you are arguing whether he is biased or not. Perhaps Mr. Connolley, who is refuting the claims made by Wagman, can produce evidence to the contrary. Instead of making personal attacks on the person, produce evidence. Who cares how bias the person is if they have the facts correct. Codingmonkey 02:17, 8 April 2007 (UTC), totally excluding a common viewpoint is bannable if carried out to extreme, the viewpoint can be moved to a different section or article if needed, eg controversy. IF a large minority percentage of the population's viewpoint is completely editted out then article is no longer neutral. —Preceding unsigned comment added by (talk) 14:10, 26 November 2009 (UTC)

RFC: renaming of article according to WP:STYLE?

[RfC tag deleted]

I contest the changes — either it should actually go according to the MoS: medieval warm period (or Medieval warm period for the title), or (better) it should stay Medieval Warm Period as it is used almost consistently throughout literature. Lars T. (talk) 23:23, 28 October 2009 (UTC)

  • It denotes a singular event and hence is a proper name. Medieval Warm Period it is - not only due to the MOS, but due to plain English language. --Stephan Schulz (talk) 22:49, 29 October 2009 (UTC)
    • Both Medieval Warm Period and medieval warm period are used in the literature; the capitalization of "Warm" is strange. It should be moved to one of Lars' two suggestions; from his comment and Stephan's, returning it to its fully-capitalized state is the current preference. Awickert (talk) 00:10, 30 October 2009 (UTC)
  • I agree with Awickert, particularly that capitalizing "Warm" but not "period" is strange. --Tryptofish (talk) 16:53, 30 October 2009 (UTC)
  • This doesn't need a RfC. Just fix it. -Atmoz (talk) 17:26, 30 October 2009 (UTC)
  • The name of an article which has been around for some time should not have been tweaked in the first place. The article is a well-established one and the Rfc should have come before any changes were made. I don't feel confident in the renaming mechanics. Perhaps Avalik would be so kind as to change it back? BobKawanaka (talk) 18:00, 30 October 2009 (UTC)

Moved to the fully capitalized version. --Stephan Schulz (talk) 20:05, 30 October 2009 (UTC)

Hockey Stick Graph

What's with the Hockey Stick graph? That graph is at least 50 years out of date.

This one's more accurate. It shows the little ice age in all its glory but doesn't quite show how warm the medivel warm period is. —The preceding unsigned comment was added by (talk) 21:47, 31 January 2007 (UTC).

Your picture is of the original hockey-stick (notice the caption: Mann et al. (1999)) - while the picture on the page contains several reconstructions, most of them newer. --Kim D. Petersen 01:00, 1 February 2007 (UTC)

The hockey stick graph is based on two papers by Mann [MBH98, MBH99] that have been proven to rely on very poor mathematics and infact being just wrong. There is nothing like a hockey stick graph (at least not in the data sets MBH used). Two scientists (McIntyre and McKitrick) tried to reconstruct the figure and found serious mistakes in the original work by Mann. These mistakes have been published [MM03, MM05a, MM05b] and meanwhile credited among the scientific community especially in the wake of the Wegmann report: For those who want to know about this matter in short, refer to this document: - McKitrick explains in short and reasonably how they came to start digging and what they found. Contact me if you have doubts about my intentions ( - As I believed that there's 'evidence' for this graph showing the global warming caused by humanity, it hit me quite hard to find out my beliefs were based on really poor use of the Principal Component Analysis (that's the fundament of this hockey stick graph). Besides I can do some maths.

Original (flawed) work by MBH: [MBH98] Mann, Michael E., Bradley, Raymond E., and Hughes, Malcolm K. (1998) “Global-scale temperature patterns and climate forcing over the past six centuries,” Nature, 392, 779-787. [MBH99] Mann, Michael E., Bradley, Raymond S., and Hughes, Malcolm K. (1999) “Northern hemisphere temperatures during the past millennium: Inferences, uncertainties, and limitations,” Geophysical Research Letters, 26(6), 759-762.

All mistakes of MBH and their effect on the data/hockey stick by MM: [MM03] McIntyre, Stephen and McKitrick, Ross (2003) “Corrections to the Mann et al. (1998) proxy data base and Northern hemispheric average temperature series,” Energy and Environment, 14, 751-771. [MM05a] McIntyre, Stephen and McKitrick, Ross (2005a) “The M&M critique of MBH98 Northern hemisphere climate index: Update and implications,” Energy and Environment, 16(1), 69-100. [MM05b] McIntyre, Stephen and McKitrick, Ross (2005b) “Hockey sticks, principal components, and spurious significance,” Geophysical Research Letters, 32, L03710, doi: 10.1029/2004GL021750

The Graph was created using software that fraudulently removed data that showed was contrary to the "Researcher's" agenda.

An example of this Agenda can be seen in the Work of Wiki Editor Stephan Schulz protecting falsified data in this article —Preceding unsigned comment added by AardvarkAvacado (talkcontribs) 21:25, 24 November 2009 (UTC)

In the light of the recent revelations of 'scientists' lying about global warming the hocky stick graph makes the entire page look suspect.It need to be removed.

Incidently I've noticed that all wiki pages are biased in favor of man-made global warming, removing key facts and presenting all information as if there were no doubt that global warming is caused by man made carbon emissions. —Preceding unsigned comment added by (talk) 06:25, 14 December 2009 (UTC)

English wine again, updates proposed

I offer this as a new section, since several sections already have discussed this,but a while ago.

"During the MWP wine grapes were grown in Europe as far north as southern Britain"

seems either too much or too little, and some of its references are a bit out of date and/or dominated by much better ones. I can think of 3 actions:

1) One could just delete that sentence.

2) OR one could at least fix/enhance the references.

I'd suggest that 7. "The History of English Wine..." and "8. Making Wine in a Changing World" are far less extensive sources than Richard Selley's "The Winelands of Britain: Past, Present, & Prospective", 2nd Edition, 2008, using his website: That's certainly worth adding.

It isn't perfectly up-to-date, and the overall map is inherently imprecise, but if one really wants to understand the history of wine in Britain from a geological+climate view, that's a 113-page book written by a serious geologist/oenophile. He suggested the creation of the Denbies vineyard, now the largest in the UK. As the grapes march North, they generally skip the Midlands, and Selley explains why (soils, especially). Selley doesn't try to show all the Abbeys and such, in part, I think, because it's hard to compare an Abbey (which would grow grapes if at all possible, regardless of the resulting wine quality) with a serious commercial operation that thinks it can sell wine competitively. Put another way, the mere existence of a vineyards is a very fuzzy proxy, as is a total count of vineyards at any point in time. The modern non-existence of an old vineyard is often due to development or local objections, examples of which Selley mentions. Anyway, it's seems odd to discuss English grapes and climate without mentioning this book at all.

Jancis Robinson's "The Oxford Campanion to Wine", Third Edition, 2006 [mentioned earlier] certainly deserves a reference, especially to pp. 178-181 (Climate) and pp. 252-254 (England), although of course these few pages don't go into the depth that Selley does.

Finally, "10. The Vineyards of England and Wales" is OK, but, looks much more comprehensive, although it can take some checking (Google & GoogleEarth) to see how far along they really are. Some are serious operations, some look like hobbies, and some are serious, but newly planted. One finds for example, that Acomb Grange, voracious rabbits devoured their newly-planted vines.

3) OR one could rewrite it into a few sentences, adding Seeley, Robinson, and references.

As is well-covered by Robinson, Selley, or Gavin Schmidt references, vineyard location is an imprecise proxy. Hence, if one is going to mention English wine at all, I'd suggest something like:

Viniculture has been practiced in England from Roman times. The location and extent of vineyards support an English temperature pattern of warm (Roman), cool (Dark Ages), warm (Medieval), cool (Little Ice Age), warm (current). Vineyard location alone are not necessarily good proxies of average English temperatures, given the many confounding factors. Vineyards are rapidly moving North, already as far as North Yorkshire (Bolton Castle, for eaxmple). These locations may not prove that current temperature exceeds that of Medieval times, but they support the reverse even less. [references as discussed above]

In support of the above:

Talking vaguely about medieval vineyards in Yorkshire doesn't really help much.

Yorkshire is split into South Yorkshire, West Yorkshire, and North Yorkshire (the largest piece). As a whole, Yorkshire has a North-South distance of ~90 miles, or about 25% of England's total. In addition, while Abbey wineries were found around York itself (elevation ~50-100 feet), there's at least one new modern vineyard (Bolton Castle) 25 miles further North and 500 feet higher, and at least 4 other vineyards North of York. West Yorkshire is North of South Yorkshire and mostly South of North Yorkshire, and York itself (where there were medieval vineyards) is in the South of North Yorkshire.

There seem to be another 4 elsewhere in Yorkshire as a whole (Acomb Grange, Leventhorpe, Summerhouse, Holmfirth), but I found 5 North of York:

A) Bolton Castle (North Yorkshire): 54deg19'20.18"N [the furthest North, and ~600 foot elevation] which says: "Although historically there would not have been a vineyard this far north, the one recently established in the lee of the castle is stocked with a modern hybrid, frost hardy and early ripening variety of red grape, Vitis Vinifera x Vitis Amurensis. In time, this small vineyard should produce up to 1000 bottles of wine a year."

And says:

"The grounds were archaeologically surveyed and gardens recreated along medieval lines, including a herb garden, a rose garden, a maze, bowling green and a vineyard - the vineyard being the only feature that would not have existed here in medieval times, although people had grown, or attempted to grow, vines in this country as long ago as the Romans."

Of course, they may or may not be correct about the non-existence of vineyard that far North - many vineyards are claimed to be the Northernmost. Also, the castle was started in 1350, which might have been late, but they do seem to have a solid history of the place.

B) Helmsley Walled Garden (North Yorkshire), 54deg14'40.53N C) Mount Pleasant (Lancashire), 54deg6'33.56"N D) Ryedale (North Yorkshire), 54deg3'44.62"N E) Yorkshire Heart (North Yorkshire), 54deg00'01.87"N

We've driven within a few miles of all of these at one time or another. Since many of these are newly-planted, it looks like a meaningful 2010 or 2011 Yorkshire Wine Tour may be at least possible. It won't be Napa, but the mere existence of such is interesting. JohnMashey (talk) 03:51, 2 February 2009 (UTC)

I think the focus here should be to elucidate to new readers rather than merely debunk the claims of a few partisan hacks. The MWP probably was warmer than now in Europe; you and WMC seem to be trying to imply that no conceivable evidence could suggest it was. But the IPCC's position is only that the MWP was "a local event", not that it didn't exist at all. Okay, so if it was a "local event", there were places on the globe where the temperature was unusually warm at the time. Where were those places? England and Europe in general were among them. You can admit this without denying the consensus. You can even admit we have some evidence it was warmer then than now in that location without denying the consensus. Like this chart from The Oxford Companion to Wine's entry on Climate Change (2nd edition, published 1999, scanned by me):
--Blogjack (talk) 15:41, 3 February 2009 (UTC)

As I've posted elsewhere, I personally don't care whether it was warmer or not, or where, during the MWP, since that has exactly zero influence on the future. I don't know how you get the "no inconceivable evidence" from me - I think you may be projecting your own strong views onto others. I just want to get an accurate, up-to-date, and unconfusing statement about British vineyards, or get rid of it.

My comments were directed specifically to the one sentence about grapes in Britain, which of course is *not* the European continent [cooler summers, warmer winters, usually].

If you want to open a separate section about grapes & temperatures on the continent, for others to argue about, that might be useful. I did take a quick look at Pfister(1988) from Third Oxford, but it didn't yield any firm conclusions about Britain. It's 20 years' old, and when it says there were vineyards in the MWP, that doesn't help much when there are vineyards today in the same areas.

However, I'd suggest a more serious discussion than posting a low-quality, unattributed chart from the Second Oxford book (1999). I couldn't find that chart in my Third edition (2006). I rather doubt it would make it into Wikipedia without the proper reference to the original paper, especially given the many ambiguities. If it has indeed disappeared from the current Edition, one might ask why, and a vague chart with little documentation is unlikely to be viewed as an authoritative reconstruction by anyone serious.

If you look at the chart carefully, it says "relative to the average for the first half of the 20th century." The horizontal line in that chart marked 0 is for the average of ~1900-1950. The "Central England Temperature Series" is the longest instrumental temperature record. I downloaded the Monthly Mean data from, and I found the average yearly CET was 9.41C for 1901-1950, 10.39 for 1999-2008 (not 1998), and 7 of the latter 10 years were above 10.41 (and as a group average 10.52). The CET anomaly of the last decade (which is *not* necessarily the same as the Europe anomaly) is ~1C above the 1901-1950 range, or for the hottest 7 years, 1.1. Assuming June-Sept wine-growing season, it's about .9C. Given that the chart has no error-bars, and no indication of the reconstruction method, these numbers are are hard to distinguish from the 1.2-1.3 there.

"Average temperature" is not the same as "vine growing season temperature", and the latter is not simply-defined as a set of months. Practical vineyard locations are not only determined by summer temperatures, but by avoidance of frost at wrong time, i.e., the entire temperature distribution matters, it has almost certainly changed [winters and especially nights warming faster than summers/days], and there are arguments (Keenan, 2007) about the reliability of using harvest dates as proxies for summer warmth.

One cannot draw any strong conclusions from all this, especially when comparing with a poorly-understood, error-bar-less chart that may or may not apply to Britain. All this is why I said, "Vineyard location alone...even less." (talk) 04:07, 4 February 2009 (UTC)

I'm only objecting to the "...even less" sentence. I agree that one cannot draw strong conclusions from all this. The balance of the evidence from vineyards is ambiguous. It does suggest it was roughly as warm then as now but does not allow us to conclude which was warmer. So why not just say that? Why pick specific parts that slightly favor your side so you can sneak in a less/more claim, however carefully worded? (Evidence in the other direction includes the sheer number of british vineyards then versus now - over 1300 by the end of the 12th century - and the fact that they managed to be so productive and reach such an extent as they did without the benefit of modern "frost-hardy hybrids".)
My local library doesn't have the OCtW 3rd edition or I would have used that. A major source for the second edition on these subjects seems to have been "John Gladstones" who wrote a book called "Viticulture and Environment" (ISBN 1875130128). One can order it for $66 here, but I haven't:  :--Blogjack (talk) 17:48, 4 February 2009 (UTC)

Grape Varieties

Has no-one considered the concept of grape varieties? New strains of grapes are created all the time. Eg the Bacchus grape that is commonly grown (because it can be grown in colder climates) in the UK has only been available for general cultivation since the 70s. I would propose that viticulture is a bad proxy as the Romans didn't have access to varieties such as the Bacchus grape. The climate changes but so does mankind's ability to cultivate.

Another aspect to consider is the demand for grapes. A change in culture could increase a demand for grapes hence an incentive to breed and plant different strains. Of course I'm being speculative here but wine popularity has generally been on the increase in the UK in the last few decades. More demand means more opportunity and incentive for farmers to experiment with grapes as a crop.

What do you think? TheJoff (talk) 02:36, 2 December 2009 (UTC)

If anything, demand has been much reduced, at least relative to population and supply. In Roman and medieval times, there was a strong cultural (Mediterranean culture revolved around it) and religious (for last supper rites) demand for wine, but wine import was very limited and expensive. Nowadays, you can buy a bottle of Chilean or Romanian wine for a Euro or Pound in Britain . But yes, the whole point of the section is to point out that viticulture is indeed a bad climate proxy. --Stephan Schulz (talk) 08:32, 2 December 2009 (UTC)