Talk:Medieval Warm Period

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Archive of talk through May 2005

Contents

[edit] Rm graph: why

SEW added the hand-drawn graph. I removed it. As a useful graph for MWP studies, its very poor, indeed quite misleading. It hasonly historical interest.If it belongs anywhere it belongs...on MWP and LIA in IPCC reports. Oh look, its there already. William M. Connolley 09:55:05, 2005-09-03 (UTC).

http://www.atmos.washington.edu/2001Q2/211/groupE/maya_files/image003.jpg

What have you got against the image? Care to explain how exactly Greenland was green in the Medieval period when, according to your lot, it was colder than now?

You are the one 'misleading' by essentially deleting an important period from history. Never let facts get in the way of the Global Warming Religion. Mixino1 13:22, 26 January 2007 (UTC)

What I've got against the image is explained in MWP and LIA in IPCC reports, with refs. The graph is a sourceless schematic that has been obsolete for years and shouldn't be used. Its also not a freely usable image. As to greenland, etc, thats quite another matter William M. Connolley 13:36, 26 January 2007 (UTC)
Your only interest is in keeping the facts from the public. Like many pages on Wikipedia, this one has a load of interferers making sure the facts are diluted and emaciated. I seriously fear for the environmental lobby's lasting effect on science being taken seriously. Obviously, for those that have sidelined climate change into a religion, the interests of science are no longer of any merit. I notice you refuse to answer the pertinent question - which is no more than I would have expected. Mixino1 02:21, 28 January 2007 (UTC)
I'm confused about the graph in this article. It makes it seem as if the MWP was actually colder then it is now. However, this article clearly states:
Results from a radiocarbon-dated box core show that SST was ~1°C cooler than today ~400 years ago (the Little Ice Age) and 1700 years ago, and ~1°C warmer than today 1000 years ago (the Medieval Warm Period).
This article was published in 1996 and temperature has risen a marginal amount since 1996. Clearly the MWP was warmer then it is now. Therefore, the graph that is show in this article is misleading/completely false. Codingmonkey 02:30, 8 April 2007 (UTC)
As Mr. Connolley pointed out below, the above article refers to the Sargasso Sea. Nevertheless, as I stated below, I would like Mr. Connolley's sources that demonstrate that global temperatures were lower in the MWP then they are today. Codingmonkey 15:44, 9 April 2007 (UTC)

[edit] 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)

[edit] anon skepicism

An anon (school board of calgary, it seems) added:

Some investigators believe that the medieval warming effect was global, and that average global temperatures between the 10th and 14th century were higher than at present, calling into question both the uniqueness of the present global warming trend and the origin of the present trend from human-generated greenhouse gases. That perspective was belittled in the 2001 IPCC report...

and other misc stuff. This is the standard misinterpretation, as is the vitiated bit. The refs added don't seem to useful and the syntax is poor, so if anyone wants them in, its up to you. William M. Connolley 19:22, 4 October 2005 (UTC).

A review of more than 200 climate studies led by researchers at the Harvard-Smithsonian Center for Astrophysics has determined that the 20th century is neither the warmest century nor the century with the most extreme weather of the past 1000 years. The review also confirmed that the Medieval Warm Period of 800 to 1300 A.D. and the Little Ice Age of 1300 to 1900 A.D. were worldwide phenomena not limited to the European and North American continents. http://cfa-www.harvard.edu/press/pr0310.html Mixino1 22:44, 29 January 2007 (UTC)
This is Soon & Baliunas, and was dodgy. See http://www.realclimate.org/index.php?p=11 #2, if interested. Which of course you aren't :-( William M. Connolley 22:52, 29 January 2007 (UTC)
Anything that quotes anything by Mann is now of no interest to me. He made a mistake. Fair enough. Everyone has made a calculation blunder at one point or another. However, he continues to treat science with contempt by claiming his mistake never happened. The whole basis of his EOS article is to defend his now disproven hockey stick. Anything that quotes him, therefore, is not worth screen space. This is one reason I find climate activists contemptible. They love ad hominem attacks by saying Dr. X or Prof. Y was once paid to investigate something by the oil industry - yet they don't see that Mann's failure to acknowledge his own error is many times worse.
I regard Mann as an untrustworthy witness for the above reason. Mixino1 02:09, 30 January 2007 (UTC)
"Dodgy" is charitable — the managing director of the journal's parent company ended up apologizing for having published the article. Raymond Arritt 22:57, 29 January 2007 (UTC)
Source? Mixino1 02:09, 30 January 2007 (UTC)
Right here. Raymond Arritt 02:43, 30 January 2007 (UTC)
So Mann, someone who has been thoroughly discredited for writing an article based on nonsense statistics and failing to admit it, writes a piece denouncing a paper that overstates its conclusions and this requires a mass of apologies? All this shows is the power of the green religion rather than the science. I have seen this kind of goading all too often. The BMJ published a perfectly valid article about passive smoking, only for the editor to have several thousands of pressure group emails and letters. Luckily the BMJ editor had bigger cahones and stuck to his guns. Consensus science, or to give it the correct title 'Mob' science, does not convince me. It is not of any scientific value .
Meet the sibling of Mob Science: Publication bias. Mixino1 03:17, 30 January 2007 (UTC)
Just to be sure - you are aware that Von Storch, who was one of the editors who quit - is one of the critiques of the Hockey-stick - right? --Kim D. Petersen 02:22, 31 January 2007 (UTC)
Quit or was pushed? You know exactly what I mean. Mixino1 20:27, 2 February 2007 (UTC)
You must not know the man. Nobody pushes von Storch around. Raymond Arritt 22:45, 2 February 2007 (UTC)

[edit] I'm confused

From the article:

"A radiocarbon-dated box core in the Sargasso Sea shows that sea surface temperature was approximately 1°C cooler than today approximately 400 years ago (the Little Ice Age) and 1700 years ago, and approximately 1°C warmer than today 1000 years ago (the Medieval Warm Period).[11] However, all the reconstructions, as shown above, appear to indicate that it was not."

What is this actually saying, in the context of the rest of the text? Doesn't the last sentence there just cancel everything else out?

Inspector Baynes 22:06, 16 October 2006 (UTC)

The last sentence is because global warming believers claim that old warming or cooling must have been local events, and there couldn't have been global warming events. (SEWilco 05:08, 17 October 2006 (UTC))
Its an odd sentence, I hope I didn't write it. To make sense, it would have to say "...it was not global" or somesuch. The easiest thing to do seems to be to remove it William M. Connolley 08:31, 17 October 2006 (UTC)

[edit] 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)

[edit] 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.' "

http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2006/11/05/nosplit/nwarm05.xml

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 (talk • contribs) 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." http://www.telegraph.co.uk/news/graphics/2006/11/12/warm-response3.pdf 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)

[edit] Hockey Stick Graph

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

http://www.geo.arizona.edu/Antevs/nats104/nhem_reconsml.gif

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 72.72.202.222 (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: http://www.uoguelph.ca/~rmckitri/research/WegmanReport.pdf. For those who want to know about this matter in short, refer to this document: http://www.uoguelph.ca/~rmckitri/research/APEC-hockey.pdf - 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 (http://www.nt.tuwien.ac.at/about-us/staff/bastian-knerr/) - 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

[edit] 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)

[edit] The graph is inaccurate

It shows that the current temperature is hotter than in the MWP. This is wrong. If Greenland was capable of supporting colonisation it must have been much warmer than it is today. I would like to see a better graph. SmokeyTheCat 07:55, 8 April 2007 (UTC)

It was, in fact, warmer. See here. I really think that the graph should be removed, it seems to go against the evidence. Codingmonkey 07:09, 9 April 2007 (UTC)
Being a perceptive chap I'm sure you noticed that you ref says in the Sargasso Sea not globally William M. Connolley 07:31, 9 April 2007 (UTC)
Good catch, I missed that. However, the Sargasso Sea does cover a large part of the North Atlantic Ocean. Nevertheless, since you say that global temperatures were lower in the MWP then present day global temperature, may I have the source? Codingmonkey 15:41, 9 April 2007 (UTC)
I removed the graph as we seem to have agreement that it was not accurate.  SmokeyTheCat  •TALK• 20:12, 19 August 2007 (UTC)
Not so fast, please. These are the best reconstructions we have available. Raymond Arritt 20:21, 19 August 2007 (UTC)
I still think that the graph is inaccurate and that seems to be the consensus here.  SmokeyTheCat  •TALK• 08:12, 23 August 2007 (UTC)
You are wrong William M. Connolley 08:28, 23 August 2007 (UTC)
Or, in more detail: The graph is sourced to a large number of reliable sources. Your personal opinion on Viking colonization is not. You might also want to look at entry in our GW FAQ. --Stephan Schulz 08:32, 23 August 2007 (UTC)

[edit] Box core

Could someone write a stub for box core and link to it? Thanks. —The preceding unsigned comment was added by 131.252.212.143 (talk) 08:24, 8 April 2007 (UTC).

I have restored the external link questioning the basis of the hocket 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 Globa warming articles. Peterlewis 16:10, 16 April 2007 (UTC)

[edit] 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)

[edit] 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: [1] and nothing links to that page [2]. 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)

[edit] Extent?

PW dislikes [3] although less extensively than they are today and uses http://www.winelandsofbritain.co.uk/lecture.htm as a source for this. But the map is clearly wrong; there are modern vineyards in Yorkshire [4]. 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
  • http://www.geocities.com/NapaValley/6630/ancient.html "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."
  • http://www.86counties.com/1-1-wine.html "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."
  • http://www.englishwineproducers.com/history.htm "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)

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

[edit] "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 [5]:
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)

[edit] 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 [6]. 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?" [7]). 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 ([8], 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 RealClimate.org 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 RealClimate.org 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 204.8.204.104 (talk) 20:46, 26 March 2008 (UTC)

[edit] 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)

[edit] 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)

[edit] 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 (http://www.winelandsofbritain.co.uk/lecture.htm) 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)

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

but i don't know how to do i citation. The reference is http://www.21stcenturysciencetech.com/Articles%202004/Winter2003-4/global_warming.pdf. Can someone add it for me, tell me how to do citations, or tell me where i can learn how to do them? 122.109.250.74 (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 123.208.29.163 (talk) 08:27, 15 May 2008 (UTC)