Guest post from Von Rudolf Kipp
Originally in German here, with some portions translated to English using the Google translator below.
[update–translation provided by poster EWCZ ~ ctm]
Google translator is largely imperfect, but to read the Google translation in English go here.
If anyone wishes to do a personal translation for the entire article, please leave a note in comments and I will replace it. Of great interest is the global graphic below, which shows that the MWP is a worldwide event, not just limited to portions of the Northern Hemisphere.
“ “Who controls the past controls the future: who controls the present controls the past.” – George Orwell, 1984
We live in an age of superlatives. When you turn on the TV nowadays, you get offered the choice of best films, the greatest hits or the dumbest opening lines of all time. And even with a detergent it is long ago not sufficient when it washes whiter than white. Again, the constant sale appeal to the consumer can be maintained only if the product is billed as “The best thing ever.”
Naturally, also the reporting on climate change must follow this trend. Therefore the upcoming conference in Copenhagen is optionally about the salvation of mankind, of whole ecosystems, or for those who like it even more bombastic, the salvation of the planet. To achieve this, we continue to learn, enormous changes in our economic and financial system are needed. Production companies and countries should put on bureaucratic manacles to control their CO2 emissions. Best with the help of worldwide dedicated government-like organizations.
What is the purpose of all this? You suspect or know it already. We are experiencing a warming, which has not existed in the history of mankind, or even in the history of the earth. And as a result we will experience the greatest disasters of all time. Honestly!
Medieval Warm Period thesis contradicts the unprecedented warming
However, one must mention that, already the first half of the statement, that about the unprecedented warming, elicits significant question marks in many climate scientists and even at many historians. Wasn’t there something like the medieval warm period? And in the opinion of many scientists, wasn’t it warmer during this period than today?
The idea of a medieval warm period was formulated for the first time in 1965 by the English climatologist Hubert H. Lamb [1]. Lamb, who founded the UK Climate Research Unit (CRU) in 1971, saw the peak of the warming period from 1000 to 1300, i.e. in the High Middle Ages. He estimated that temperatures then were 1-2 ° C above the normal period of 1931-1960. In the high North, it was even up to 4 degrees warmer. The regular voyages of the Vikings between Iceland and Greenland were rarely hindered by ice, and many burial places of the Vikings in Greenland still lie in the permafrost.
Glaciers were smaller than today
Also the global retreat of glaciers that occurred in the period between about 900 to 1300 [2] speaks for the existence of the Medieval Warm Period. An interesting detail is that many glaciers pulling back since 1850 reveal plant remnants from the Middle Ages, which is a clear proof that the extent of the glaciers at that time was lower than today [3].
Furthermore, historical traditions show evidence of unusual warmth at this time. Years around 1180 brought the warmest winter decade ever known. In January 1186/87, the trees were in bloom near Strasbourg. And even earlier you come across a longer heat phase, roughly between 1021 and 1040. The summer of 1130 was so dry that you could wade through the river Rhine. In 1135, the Danube flow was so low that people could cross it on foot. This fact has been exploited to create foundation stones for the bridge in Regensburg this year [4].
Clear evidence of the warm phase of the Middle Ages can also be found in the limits of crop cultivation. The treeline in the Alps climbed to 2000 meters, higher than current levels are [5]. Winery was possible in Germany at the Rhine and Mosel up to 200 meters above the present limits, in Pomerania, East Prussia, England and southern Scotland, and in southern Norway, therefore, much farther north than is the case today [6]. On the basis of pollen record there is evidence that during the Middle Ages, right up to Trondheim in Norway, wheat was grown and until nearly the 70th parallel/latitude barley was cultivated[4]. In many parts of the UK arable land reached heights that were never reached again later.
Also in Asia historical sources report that the margin of cultivation of citrus fruits was never as far north as in the 13th century. Accordingly, it must have been warmer at the time about 1 ° C than today [7].
Archeology and history confirm interglacial
Insects can also be used as historical markers for climate. The cold sensitive beetle Heterogaster urticae was detected during the Roman Optimum and during the Norman High Middle Age in York. Despite the warming of the 20th century, this beetle is found today only in sunny locations in the south of England [8].
During the medieval climate optimum, the population of Europe reached hitherto unknown highs. Many cities were founded at this very time with high-altitude valleys, high pastures and cultivated areas, which were at the beginning of the Little Ice Age again largely abandoned [9].
The Middle Ages was the era of high culture of the Vikings. In this period their expansion occurred into present-day Russia and the settlement of Iceland, Greenland and parts of Canada and Newfoundland. In Greenland even cereals were grown about this time.. With the end of the Medieval Warm Period the heyday of the Vikings ended. The settlements in Greenland had to be abandoned as well as in the home country of Norway, during this time, many northern communities located at higher altitudes [10]. The history of the Vikings also corresponds very well to the temperature reconstructions from Greenland, which were carried out using ice cores. According to the reconstructions, Greenland was at the time of the Vikings at least one degree warmer than in the modern warming period [11].
Climate scientists want to eliminate contradictions
Until about the mid-90s of last century the Medieval Warm Period was for climate researchers an undisputed fact. Therefore in the first progress report of the IPCC from 1990 on page 202, there was the graphics 7c [12], in which the Medieval Warm Period was portrayed as clearly warmer than the present. However, the existence of this warm period became quickly a thorn in the side for the scientists responsible. When in 12th century without human influence the climate has been even warmer than at the height of industrialization, why should the current warming have non-natural causes?
Thus, the Medieval Warm Period was soon declared an odious affair. Meanwhile, an e-mail is legendary, which was sent to a U.S. climate researcher David Deming [13] in 1995. This scientist published an article in the prestigious journal Science in which he had presented research on climate change in North America based on cores [14].
With this publication, he was immediately known among climate researchers, and some of them obviously thought that he was toeing their line [13, 15]:
“With the publication of the article in Science, I gained significant credibility in the community of scientists working on climate change. They thought I would be one of them, someone who would pervert science in the service of social and political causes. So one of them dropped his guard. An important person working in the field of climate change and global warming sent me an astonishing email with the words: ‘We must get rid of the Medieval Warm Period’. ”
Meanwhile, the climate machinery for the eradication of the Medieval Warm Period has already started. In 1995, the English climatologist Keith Briffa published in the journal Nature a study with sensational results. According to his studies of tree rings in the Siberian Polar-Ural, there had never been a Medieval Warm Period and the 20th century, suddenly appeared as the warmest of the last 1000 years [16]. The real breakthrough was the thesis of 20th Century experience as the warmest of the millennium, but not until three years later, and that with the release of Michael Mann’s infamous Hockeystick [17, 18].
Warm period is extinguished
In this diagram that became the icon of human-induced global warming in the 3rd IPCC Assessment Report, the Medieval Warm Period has now been completely eradicated. However, this curve was quickly under attack, mainly because the Canadian mathematician Steven McIntyre had serious doubts about the correctness of the representation and those pursued with the meticulousness of an auditor [19]. McIntyre showed not only that Mann had used an algorithm that resulted in 90 percent of the cases to a hockey stick, but found also serious errors in the selection of the data and the location of places, as well as the use of incorrect data [20].
Of course, the Mann’s gang could not let these allegations unanswered. In response, Realclimate.com was founded, a name intended to suggest the truth, but somehow reminiscent of the Real Ghostbusters, a poorly made copy of the genuine, which in contrast to the original only pretends to be the right thing. This webpage was henceforth used for accusations and slanders against the non-“believers” [21]. It took also increasingly care not to call McIntyre, in the meantime identified as the main enemy, by his name.
Following the publication of Michel Mann’s hockey stick and the criticism, whole series of further studies was published to demonstrate that the results of Mann’s actually represented the real temperatures over the last 1000 years. The highpoint of the debate was the forced disclosure of the raw data from tree ring studies long held under lock and key, which served as one of the principal witnesses for the correctness of the thesis of the unusually warm 20th century. It turned out that clearly the data were selected intently to get the desired result [22].
Conflicting data
Regardless of the debate over the proper or improper use of proxy data like tree rings to determine the temperature history, mainstream climate researchers, however, are still struggling with a whole series of problems. What was with all the archaeological data, the records of weather events in church records and historical facts, which clearly documented that in the Middle Ages, there was an unusually warm period? Quite simply, the attempts to refute these arguments were made based on claims that all these phenomena indeed existed, but only as geographically limited events [23]. If the Middle Ages was warmer somewhere than today, then maybe it was only in England, the Alps, Greenland or North America. Globally, however, as shown in the many hockey stick charts, it has been colder than at the end of the 20th century.
If one, however, provides an overview of the literature on the subject of Medieval Warm Period, which has been published in recent years, there will be a completely different picture. There are now quite a number of studies from around the world, showing all one thing. And indeed, that the High Middle Ages were warmer than today. An excellent overview can be found on the website CO2 Science, which has set up a whole section for studies of this kind [24]. There are now 765 different scientists from 453 research institutes listed that have worked on the medieval warm period. A small portion of these studies is shown in the figure below [Click 25] (by the graph, you get a larger image where you can select individual work).
This survey shows one thing quite clearly. At the time of the Middle Ages, that is, from 1000 to 1300 it was almost everywhere in the world warmer than today. There have been periods of warming, that exceeded 0.6 degree Celsius rise in temperature in the 20th century and totally without the man-made increased emissions of the supposed “climate killer” of CO2. The statements, that there has not been any Medieval Warm Period, or it was merely a localized phenomenon, can safely be regarded as untenable.
It is therefore not surprising that there are influences on the climate, which can by far exceed the CO2 as a driver of climate variability. This hypothesis is massively supported by the observations made during the last 10 years. Finally, we have been experiencing no increase since 2002, the temperatures have dropped slightly [26]. And that even though the emissions of CO2 from fossil fuels in exactly the same period increased to previously unmatched dimensions.
Google translation in English of the full article is here.
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If no one else has offered yet (I didn’t read all of the comments), I may be able to translate this, but it will take a little time. I studied German and even lived in Hamburg briefly, but it’s been a while, and some of the words used in the article are not that common.
A small nit to pick.
Moderator — might want to consider changing “phenonmenon” in title to phenomenon.
[Thanx, done. ~dbs, mod.]
Of interest in the Penn State investigation of Michael Mann is the Academic Integrity Policy of the College of Earth and Mineral Sciences, which begins with:
++++++++++++++++++++++++++++++++++++++++++++++++
Academic integrity is the pursuit of scholarly activity in an open, honest and responsible manner. Academic integrity is a basic guiding principle for all academic activity in the College. All students should act with personal integrity, respect other students’ dignity, rights and property, and help create and maintain an environment in which all can succeed through the fruits of their efforts.
Academic integrity includes a commitment not to engage in or tolerate acts of falsification, misrepresentation, or deception. Such acts of dishonesty violate the fundamental ethical principles of the EMS community and compromise the worth of work completed by others.
To protect the rights and maintain the trust of honest students and support appropriate behavior, EMS faculty will regularly communicate high standards of integrity and reinforce them by taking reasonable steps to anticipate and prevent acts of dishonesty in all assignments. At the beginning of each course, the instructor will provide students with a statement clarifying the application of EMS academic integrity policies to that course.
++++++++++++++++++++++++++++++++++++++++++++++++
The full statement is at:
http://www.ems.psu.edu/current_undergrad_students/academics/integrity_policy
Note the links at the end. The policy seems to be intended for students. Perhaps there are other policies for professors and staff.
This quote: Furthermore, historical traditions, are evidence of unusual warmth at this time. Years brought the 1180s the warmest decade ever known winter. In January 1186/87, the trees were in bloom, near Strasbourg. And earlier you come across a longer heat phase, roughly between 1021 and 1040th The summer of 1130 was so dry that you could wade through the river Rhine. In 1135, the Danube took so little water that they could cross on foot. This fact has been exploited to create this year, the foundation stone for the bridge from Regensburg to [4].”
Nothing like actual history to tell the story.
The MWP…is a roaring lion that is next to impossible…to get rid of.
GRRRRRRRRRRR!
Chris
Norfolk, VA, USA
I think if you look carefully at the data presented on this figure, then it tends to support the basic conclusion of Mann and others, namely that to the extent that different records tend to show a warm period sometime in the range of 800-1400 A.D., these periods tend to be asynchronous.
Wardrobe / sensor drift malfunction.
Maybe it’s time to revisit this.
http://wattsupwiththat.com/2009/02/18/nsidc-satellite-sea-ice-sensor-has-catastrophic-failure-data-faulty-for-the-last-45-days/
I have now manged to have the full article translated to English. I am sure, that it is still far away from perfect, so it would be nice if you could report mistakes, badly used idioms etc in the comments section on my blog.
The Medieval Warm Period – a global phenomenon. Unprecedented warming or unprecedented data manipulation?
On the global MWP, see Loehle and McCulloch (EE 2008), linked at http://www.econ.ohio-state.edu/jhm/AGW/Loehle/.
Well Leopardi in 1800’s talks about warming period, seasons that lost its mind refering something that Magalotti wrote in 1683 : See chapter XXXIX http://www.leopardi.it/pensieri.php
” La quale immaginazione è così fondata, che quel medesimo appunto che affermano i nostri vecchi a noi, affermavano i vecchi, per non dir più, già un secolo e mezzo addietro, ai contemporanei del Magalotti, il quale nelle Lettere familiari scriveva: “egli è pur certo che l’ordine antico delle stagioni par che vada pervertendosi. Qui in Italia è voce e querela comune, che i mezzi tempi non vi son più; e in questo smarrimento di confini, non vi è dubbio che il freddo acquista terreno. Io ho udito dire a mio padre, che in sua gioventù, a Roma, la mattina di pasqua di resurrezione, ognuno si rivestiva da state. Adesso chi non ha bisogno d’impegnar la camiciuola, vi so dire che si guarda molto bene di non alleggerirsi della minima cosa di quelle ch’ei portava nel cuor dell’inverno”. Ouesto scriveva il Magalotti in data del 1683. L’Italia sarebbe più fredda oramai che la Groenlandia, se da quell’anno a questo, fosse venuta continuamente raffreddandosi a quella proporzione che si raccontava allora.
È quasi soverchio l’aggiungere che il raffreddamento continuo che si dice aver luogo per cagioni intrinseche nella massa terrestre, non ha interesse alcuno col presente proposito, essendo cosa, per la sua lentezza, non sensibile in decine di secoli, non che in pochi anni.”
A translation here:
http://omniclimate.wordpress.com/2008/02/26/leopardi-1832-onclimate-change/
Now about the image above extrapolating such a small number of data measurements to evidence worlwide medieval Warming period is a stretch.
Al Gore won his Nobel on the basis of a total fraud.
Fitting.
http://wattsupwiththat.com/2009/11/28/how-the-trick-was-pulled-off/#more-13328
… shows “The LFD curve indicates low-frequency density changes produced by processing the original data in a manner designed to preserve long-timescale temperature signals (Briffa et al., 1998c).” I would imagine this is what should be most useful in looking at the MWP and LIA ?
I extracted the LFD curve here:
http://uploader.polorix.net//files/1585/briffa3%20mod.jpg
The LIA is apparent and with temperatures falling after a 1940 high.
Now this graph looks very different to Briffra 2000:
http://www.climateaudit.org/?p=693
What is going on here ?
In 793 some ships came to the eastern shoreline of Northumberland, at a monastery on Lindisfarne (Holy island). The men, danes as they were called, had stayed in the near waters of Scotland, and attacked the monastery by way of ship after winter. In the document recording the attack the date January 8 is written. This is generally regarded as the beginning of the Viking age.
However, scholars are saying that this date must be wrong because attacks like these weren’t possible in wintertime. They favour June 8 as the right date. Why are they changing the date? Because they think it was too cold for an attack.
But there are some facts that may contradict these scholar’s theory. Januari 6 is a date of great weight in the catholic church. It’s the day on which the three kings were supposed to have reached Bethlehem to see the newborn baby Jesus (the day of Epiphany). All over the christian world of the middle ages this day was a day when much wealth poured into churches and monastaries. Attackers such as the danes were of course aware of this and they could have waited two days until the festivals were over and done. Many of the danes of this time were actually christians, albeit arian or orthodox christians, so they could have gathered information about the festivities when visiting the monastery.
Another fact is that the late 8th century is recorded as having very mild winters in England and Scotland with little or no ice as well as not much snow so staying in Scotland over Winter must have been a somewhat easy task for these sailors. After all, many attacks from the goths some 500 years earlier came in wintertime.
My point with this comment is that this story from the early middle ages shows that is was warmer back then. Who in their right mind would set out in an open boat in early January today?
BTW, the term Viking age could very well be replaced with early middle ages. No one in those days from Scandinavia wouldn’t even have known what that word meant in the 8th, 9th and 10th centuries. The first time the word viking is recorded is in english (old english wicing) and then used as a word for people from other nations living in the english towns (old english wic = town, related to latin villa and vicus, meaning village). When talking about raids, invasions from the people of Scandinavia the english had the word dane (old english dene, plural for old danish dan).
The modern meaning is from a revival of the old norse word vikingr, which means scoundrels, crooks living in towns.
Joel Shore (19:14:53) :
to the extent that different records tend to show a warm period sometime in the range of 800-1400 A.D., these periods tend to be asynchronous.
Meanwhile, the Mann and CRU reconstructions don’t show anything at all.
Alan:
“This page looks at the leaked CRU emails in terms of the Medieval Warm Period:”
Thank you Alan. Very good link. Possibly it desevers it’s own thread.
I’m glad to see history getting out. CO2 Science has a lot of information on the MWP, on all continents. http://www.co2science.org/data/mwp/mwpp.php
I have a translation to more readable English for you. Send me your email address and I’ll send the rest(with hyperlinks but without the pictures. Here is what will fit in this section:
Unprecedented Warming or unprecedented data manipulation?
“Who controls the past controls the future: who controls the present controls the past.” – George Orwell, 1984
We live in a time of superlatives. If one turns on the TV, one is offered the choice of the best films; the greatest hits or the dumbest opening lines of all time. And even with laundry soap, it is no longer good enough that it can wash whiter than white. Even here the desire to purchase can be aroused in the end user only when the product is praised as ‘The greatest of all time’.
The state of reporting on Climate Change must naturally follow this same trend. At the upcoming Copenhagen conference, one can choose reports about the salvation of mankind or of complete ecosystems or, if one prefers something a bit more bombastic, the entire planet. To achieve this, we learn further that massive changes to our economic and financial systems are necessary. Productive enterprises and countries should be fettered with bureaucratic chains in order to be able to control their CO2 emissions. Preferably with a worldwide government-like organization regierungsähnlichen Organisation. created just for that purpose.
Why this great need? You suspect or know it already. We are experiencing a warming such as has never occurred in the history of mankind or even in the history of the earth. And as a result, we are about to experience the greatest catastrophe of all time. … Really!
The Medieval Warm Period contradicts the thesis of an unprecedented warming.
However, one must mention that the first half of the title which refers to warming such as has never before existed, raises clear questionmarks for several climate scientists as well as for many historians. Was there not once something such as the medieval warm period? And was it not, in the opinion of many researchers, warmer then than it is today?
The idea of a medieval warm period was first formulated in 1965 by the English climatologist, Hubert H Lamb[1]. Lamb, who in 1971 founded the British Climate Research Unit (CRU), saw the high point of the warm period between 1000 and 1300 AD i.e. in the High Middle Ages. He estimated that the temperature then was 1-2 C higher than the normal period defined as 1931-1960. In the far North, it was even as much as 4C warmer. The regular voyages of the Vikings between Iceland and Greenland was scarcely hinder by drift ice and many burial places of Vikings in Greenland are now found in the Permafrost.
Glaciers were smaller than today.
Likewise the existence of the Medieval warm period is also attested by the worldwide retreat of glaciers for the period between about 900 and 1300 [2]. An interesting detail is also that many glaciers which have been retreating since 1850, release plant remains from the middle ages which is a clear proof that the extent of the glaciers then was less than it is today.[3]
Also historical traditions point to unusual warmth in this time. The decade of the 1180’s provided the warmest winters ever known. In January 1186/87, the trees of Strasbourg were in bloom. Earlier there was a longer heat phase between approximately 1021 and 1040. The summer of 1130 was so dry that one could wade through the Rhine river. In the year 1135, the Danube had so little water that one could cross on foot. This circumstance was used in that year to lay the foundation for the stone bridge at Regensburg.[4]
Clear evidence for the warm phase of the high middle ages is also found in the limits of crop cultivation. The treeline in the Alps rose to 2000 meters which is higher than the current level.
Wine cultivation was possible in Germany in the Rhine and Mosel valleys up to 200 meters over the present limits as well as in Pomerania, East Prussia, England, Southern Scotland and in southern Norway, therefore much farther north than is the case today.[6] Pollen findings demonstrate that during the Middle ages wheat was cultivated in Norway as far north as Trondheim and barley was cultivated to nearly the 70th latitude[4]. In many parts of Great Britain, the amount of arable land reached levels that have never again been achieved.
Also in Asia, historical sources report that the limit of citrus cultivation have never been as far north as it was in the 13th century. Accordingly it must have been about 1 C warmer then than it is today.[7]
Archeaology and history confirm the warm period.
Insects can also be used as historical climate markers. The cold-sensitive beetle Heterogaster urticae can be identified archaeologically in York during the Roman optimum and during the Norman High Middle Ages. Despite the warming of the 20th century, this beetle can today only be found in sunny locations of southern England. [8]
During the medieval Climate Optimum, the population of Europe reached hitherto unknown levels. Many cities were founded in this time including those originating in high mountain valleys and meadows which at the beginning of the little ice age had to be abandoned. [9]
The middle ages were the time of high culture for the Vikings. In this period they expanded into present day Russia and settled Iceland, Greenland as well as parts of Canada and Newfoundland. In Greenland at this time cereal crops could be grown. With the end of the Medieval warm period came also the end of the Viking Bloodtime (heydey). The settlements in Greenland were abandoned and even in the homeland Norway, many of the more northern or higher altitude settlements were left. [10] The history of the Vikings is also in good agreement with the reconstructed temperature record derived from Ice cores. Accordingly, it was at least a degree warmer in Greenland during the time of the Vikings than it is during the modern warming period.[11].
Climate Scientists wish to eliminate contradictions.
Until the mid-90’s in the last century, among climate researchers, the Medieval warm period was an undisputed fact. So in the first progress report of the IPCC from 1990, the figure 7c was found on page 202 [12]. In this figure, the Medieval Warm Period is clearly shown as warmer than the present. However the existence of this warm period quickly became a thorn in the side of the responsible scientists. If in the 12th century without human influence, it was even warmer than at the high point of industrialization, why should the current warming have non-natural causes?
So the Medieval warm period was soon declared a ‘verdammenswerten’ (worthy to be completely damned) opportunity. Meanwhile legendary is the email, which the American Climate researcher David Deming [13] received in 1995. He had in that year published in the renowned magazine Science, his investigation of climate change in North America via cores (Bohrkernen)[14]. With this publication, he at once became known among climate researchers, many of whom apparently assumed that he was in line with them. [13.15]:
„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. So 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.’“
Thus the Climate-Maschinerie (machination) was already started for the eradication of the Medieval Warm Period. In 1995, the English climatologist Keith Briffa published in the magazine Nature a study with sensational results. According to his investigations of tree rings in Siberian ‘Polar-Ural’, the medieval warm period never occurred and the 20th century suddenly appeared as the warmest of the last 1000 years. The thesis that the 20th century was the warmest of the millennium experienced its real breakthrough however three years later with the publication of Michael Mann’s infamous hockeystick [17,18].
Warm Period is erased.
In this diagram that the Icon’s of anthropogenic Global Warming presented in the 3rd IPCC progress report, the Medieval Warm period was now completely eradicated. However this curve quickly came under attack, mostly because the Canadian mathematician Steven McIntyre had great doubt on the correctness of the representation and went after it with the meticulousness of an auditor [19]. McIntyre showed not only that Mann had used an algorithm that 90% of the cases led to a hockeystick, but also showed more serious errors in the selection of data and the
assignment of locations as well as the use of erroneous data [20].
Naturally, the clique around Mann, the so-called Hockey-Team, could not allow this reproof to stand. In reaction, the site Realclimate.com was founded, a name which should suggest the Truth but somehow reminds one of the Real Ghostbusters [cartoon version of the movie], i.e. a poorly made copy of the Original that in contrast to the original only pretends to represent the Richtige [correctness]. These pages were used from this time on to launch accusations and defamations against non-‘rechtgaeubige’ [right believers][21], Whereby care was increasingly taken, as much as possible not to mention McIntyre (the main enemy) by name.
In consequence of the publication of Michael Mann’s Hockey Stick and the critique thereof, there arose row-wise studies that should have shown that the results of Mann truely represent the actual temperature course of the last 1000 years. A preliminary high point of the debate was the forced disclosure of the long locked raw data from tree-ring studies which had served as a principal witness for the correctness of the thesis of unusual warming in the 20th century. It was thereby established that clearly data had knowingly been selected, in order to come to the desired result.[22]
Contradictory data
Independent of the discussion over the correct or incorrect use of proxy data such as tree rings for the determination of temperature history, the Mainstream-Climateresearchers had to battle a whole series of problems. What was to be done with all the archaeological data, the mentions of weather events in church books and historical facts, that very clearly showed an unusually warm period existed in the middle ages? Quite simply, one attempted to craft the argument that yes, all these phenomena had occured however, they are all exclusively regionally isolated events.[23]. When somewhere during the middle ages it is supposed to have been warmer than the present, then perhaps in England, the Alps, Greenland or North America. Globally however, it would be certain at that time, as the many hockeystick diagrams show, that it had been colder than at the end of the 20th century.
When one however generates an overview of the literature on the subject of the Medieval Warm Period, that have been published in recent years, a completley different picture arises. There are a large number of studies from all around the world that all show the same thing: that at the time of the high middle ages, it was warmer than today. An excellent overview can be found on the internet site CO2-Science, which has created an entire section for studies of this kind.[24]. There one can count 765 different scientist from 435 research institutions whose work has fleshed out the Medieval Warm period. A small portion of these studies is represented in the following picture[25] (by clicking on the graphic, you will obtain an enlarged image from which individual studies can be chosen.)
This survey makes it completely clear, At the time of the High Middle ages, between 1000 and 1300 it was almost everywhere around the world, warmer than today. There have been phases of warming that still exceed the 0.6 C temperature rise of the 20th century. and that completely without any anthropogenic influence of increased emission of the putative ‘climatekiller’ CO2. The statement, that the Medieval Warm period either did not occur or was only a locally limited phenomenon, can safely be considered as untenable.
It is therefore truer that there are other factors that influence climate that widely exceed the
ability of CO2 as a driver of climate variability. This thesis is further massiveley supported by the observations of the last 10 years. Finally since this time we have experienced no more temperature increase and since 2002, the temperature has even fallen slightly. And that despite the increase in CO2 levels to all-time levels by the emission of CO2 from fossil fuels in exactly the same time frame.
Sources:
(Same as original)
Thanks for doing the fine translation, Rudolf.
Joel Shore (19:14:53) :
“I think if you look carefully at the data presented on this figure, then it tends to support the basic conclusion of Mann and others, namely that to the extent that different records tend to show a warm period sometime in the range of 800-1400 A.D., these periods tend to be asynchronous.”
Joel, there are many types of proxies here, and many of the non tree ring proxies tend to have very bad dating characteristics. So if you see lake sediment dating as showing events at a different time than tree ring dating, that doesn’t mean that it was. But as I look at these graphs I still see a majority of them having an MWP that was warmer than today somewhere between 900 and 1100.
Also take a look at the global, non tree ring proxy that Loehle and McCulloch did. It’s linked about three posts below yours.
Calgary does not pay for such a non existant service. I was with you for a while…
Oh dear, this is just too unfortunate. I was interested by this link, had a look at the image and then (as a true sceptic ought to do) started clicking on the data. And I’m ashamed by the fraudulent use of data that’s gone on here.
First of all, some of the papers cited (with graphs displayed) perfectly disprove the concept of a global MWP, for example
http://pages.science-skeptical.de/MWP/Dansgaard-1975.html
in which the authors make the point that there is a correlation offset in temperatures of ~250 years between England and Greenland (see, for example, fig. 3 in this paper). What this means is that a ~200-300 year period of slightly warmer temperatures (an anomaly of about 0.6 degrees C) in Greenland was over around 1000AD, around the starting point for slightly warmer temperatures in England (an anomaly of about 0.4 degrees C) for 200-300 years. This timing in Greenland is also supported by
http://pages.science-skeptical.de/MWP/Johnsen-2001.html
Unfortunately, 1000AD is about the time Europe may have just been *starting* to become a little warmer, as suggested by
http://pages.science-skeptical.de/MWP/Sicre-2008.html
and
http://pages.science-skeptical.de/MWP/Grudd-2008.html
— in other words, whilst both Greenland and Europe seem to have had a 200-300 year period of slightly warmer temperatures, the timing for these don’t overlap and thereby disprove the concept of a global-wide MWP.
In support of this notion, there’s absolutely no evidence of an MWP in Ellesmere Island, right by Greenland, as shown here:
http://pages.science-skeptical.de/MWP/Cook-2009.html
(where the letters “MWP” are over a period of variation no warmer than the data preceeding it for 3000 years — see fig. 9 in that paper).
The basic problem with this little collection of proxy data, as far as I can tell, is that the compilers have deliberately sought out any little spike in the graphs at any time around 1000AD +/- 500 years. A big “MWP” is then placed over the spike, irrespective of the variable noise in the proxy data, the magnitude of the spike, or even whether, in fact, the timing correlates with the MWP in Europe. This isn’t science, where an attempt is made to prove the null hypothesis; rather, this is delusion, where every attempt is made to prove the actual hypothesis and all evidence to the contrary is swept away.
(It’s worth noting, incidentally, the magnitude of some of the temperature rises that have been labelled “MWP” — most appear to be between 0.5 to 1 degree C. And this raises an important point — if you accept that temperature and climate were *noticeably* different in Europe during the MWP with a total warming of less than 1 degree C, what do you think a rise of 2-6 degrees will be like?)
“Hockey stick” – the “Piltdown man of our time”?
I don’t understand what the MWP has to do with AGW, since it occurred in an era when there was no AGW. AGW is about one thing and one thing only: what will happen to the Earth’s climate system in response to a sharp and sustained change in the composition of the atmosphere?
There has never been a global high-tech civilization on Earth before the present one, so it is rather pointless to try and understand the impact of our current industrial civilization by studying mechanisms and events that have nothing to do with it.
Anders L. (23:57:49) :
AGW is about one thing and one thing only: what will happen to the Earth’s climate system in response to a sharp and sustained change in the composition of the atmosphere?
Au contraire — AGW posits that the Earth has *never* been warmer than it is today solely due to the increase in manmade CO2, so it must ignore the evidence of periods when it *has* been warmer. Showing that evidence knocks the pins out from under the AGW argument.
There has never been a global high-tech civilization on Earth before the present one, so it is rather pointless to try and understand the impact of our current industrial civilization by studying mechanisms and events that have nothing to do with it.
That’s like saying there were never any gliders capable of supporting the weight of a man before Otto Lilienthal’s inventions, so it is therefore pointless to study the mechanisms an albatross uses to soar for hundreds of miles.
>>I don’t understand what the MWP has to do with
>>AGW, since it occurred in an era when there was
>>no AGW.
That is the whole point Anders.
If it was warmer back in the Medieval period, when there was no fossil fuel burning of any significance, then the recent warming of the Earth may well be natural too. Plus, Gore, et al, cannot claim that this recent warming to be utterly unique, as a method of scaring people.
The MWP is a problem for the AGWs, and so it had to be manipulated out of the arguments.
And this is why the recent Yamal cooling was such a problem (Hide the Decline). If Yamal trees cannot show our recent warming (if there was any), then how can they be used as evidence to eradicate the MWP??
Quite a problem, really.
.
Geo,
This is very well put, and is exactly what awoke me to the fact that the figures might be fudged:
“Having said that, there is no question in my mind that “attacking” the MWP is the largest strategic error the Warmists have made. . . .for the simple reason that there are a lot more amateur historians than amateur scientists in the world, and that one thing did more to damage their ability to get by with “appeals to authority” in more minds than any thing else they could have done. If they were diddling what we did understand, there was no reason to feel confident that they weren’t diddling what we didn’t understand. . .”