Dead Again. Medieval Warming, Not So Much.

December 7, 2015

A study that is completely not surprising to paleo climate experts I have spoken to, underlines again the localized nature of the so-called “Medieval warming period”, an article of faith among the denierati.

Telegraph Voice:

The new study found the effects of the Medieval Warm Period did not extend to Greenland and other parts of the globe so climate was less important in their demise.

‘The concept is Eurocentric – that’s where the best-known observations were made.

“Conceiving the end of Norse Greenland as a case of maladaptation by an inflexible society in the face of climate change allows neither justice to their innovation nor appropriate lessons to be drawn from that completed experiment”, notes a recent study advancing such a multicausal understanding of the Viking departure.

A new study questions the popular notion that 10th-century Norse people were able to colonize Greenland because of a period of unusually warm weather.

Led by Erik the Red, Vikings first landed in south western Greenland after sailing from recently settled Iceland in around 985 AD. However, these colonies disappeared between about 1360 and 1460, leaving only ruins. The native Inuit remained, but Europeans did not re-inhabit Greenland until the 1700s. Thus, popular authors and some scientists have fixed on the idea that nice weather drew the settlers to Greenland, and bad weather froze and starved them.

Climate change is blamed for many things in history, but it seems that it can now be ruled out as an explanation for why the Vikings had abandoned their settlements in Greenland by the mid-15th Century after 400 years of valiant occupation.

Historians argued alongside climate change hostilities with the Inuit, a decline in ivory trade, soil erosion caused by cattle or a migration back to Europe to farms depopulated by the Black Plague played a role too.

Studying Beryllium 10 isotopes in boulders left in Greenland by 1,000 years of glacial movement, the researchers found the rocks were deposited by advancing glaciers between 975 and 1275 when the Norse had arrived and settled there.

“If the Vikings travelled to Greenland when it was cool, it is a stretch to say deteriorating climate drove them out”, Young pointed out.


“What’s novel here is both the new glaciological data from Greenland and the implications that has for the prevailing wisdom about the Norse colonization of Greenland and what it says, or doesn’t say, about Medieval climate”, says Michael Mann, a climatologist at Penn State University who has published extensively on temperature variations in the North Atlantic region both in the present and in past eras, but was not involved in the study. On the other hand, lake-bottom sediments from southwestern Greenland studied in 2011 by Lamont-Doherty paleoclimatologist William D’Andrea, suggest it might indeed have been warm when the Norse arrived, but that climate cooled starting in 1160, well before the Little Ice Age. Other studies of the region suggest a more complex picture.

With a population that peaked at about 5,000 individuals, they were the most westerly-living Europeans for several centuries until Columbus discovered America, but something happened in the 15th Century that led them to abandon their remote settlements in the West and then East of southern Greenland. The results from western Greenland and Baffin Island show there was no major fluctuation during the medieval warm period, with other records from sites closer to Viking settlements showing the same. Measurements of chemical isotopes within the rock suggest settlers in neighboring Greenland faced cold weather.

This coincided with the warm period across Europe.

Gifford Miller, a paleoclimatologist at the University of Colorado, called the paper “a coup de grace on the Medieval Warm Period”.

Astrid Ogilvie, a climate historian now based at Iceland’s Akureyri University, said the study “shows that the climate is clearly more complicated and variable than people earlier assumed”.

Columbia University:

The Greenlandic Vikings’ apogee coincided with the Medieval Warm Period (also known as the Medieval Climate Anomaly), generally dated from about 950-1250; their disappearance followed the onset of the Little Ice Age, which ran from about 1300-1850. Both periods are firmly documented in European and Icelandic historical records. Thus, popular authors and some scientists have fixed on the idea that nice weather drew the settlers to Greenland, and bad weather froze and starved them. But there are no early historical climate records from Greenland. Recently, historians have proposed more complex factors in addition to, or instead of, climate: hostilities with the Inuit, a decline in ivory trade, soil erosion caused by the Vikings’ imported cattle, or a migration back to Europe to farms depopulated by the Black Plague.

In the new study, the scientists sampled boulders left by advancing glaciers over the last 1,000-some years in southwest Greenland, and on neighboring Baffin Island, which the Norse may also have occupied, according to newly uncovered evidence.  Glacial advances during the Little Ice Age have wiped out most evidence of where the glaciers were during the Norse settlement. But Young and his colleagues were able to find traces of a few moraines—heaps of debris left at glaciers’ ends—that, by their layout, they could tell predated the Little Ice Age advances. Using newly precise methods of analyzing chemical isotopes in the rocks, they showed that these moraines had been deposited during the Viking occupation, and that the glaciers had neared or reached their later maximum Little Ice Age positions between 975 and 1275.  The strong implication: it was at least as cold when the Vikings arrived as when they left. “If the Vikings traveled to Greenland when it was cool, it’s a stretch to say deteriorating climate drove them out,” said Young.

The findings fit with other recently developed evidence that the effects of the Medieval Warm Period were not uniform; some places, including parts of central Eurasia and northwestern North America, may actually have cooled off.



2 Responses to “Dead Again. Medieval Warming, Not So Much.”

  1. dumboldguy Says:

    Spreading lies and misinformation about the Medieval Warm Period is most definitely an “article of faith” among the deniers, and it is, unfortunately, all too easy for the science illiterate to suck up and believe. Just as is “there has been no rise in global temperatures for 15 years”.

    Dumanoski in The End of the Long Summer discusses the thoughts of archaeologist Thomas McGovern re: the demise of the Greenland Colonies. McGovern blames it on a “cultural failure”. The Greenland colonies were always on the brink because the settlers tried to impose Norwegian and Scandinavian modes of agriculture and culture on the different situation in Greenland. That if they had imitated the Inuit when it got colder they might have survived.

    “Alternatives were at hand but were ignored because of cultural bias and fear of losing their European identity. Culture played a key role in the colony’s extinction”.

    Dumanoski also discusses the work of Paul Bohannon and his belief that cultural traditions can become cultural “traps” and collapse, and relates that to our situation today. I cannot recommend Dumanoski’s book too highly—-I’m just past halfway through it, and it approaches spell-binding in its insights.

  2. Well… maybe something from my country:
    Medieval climate warming reflected in the pollen and macrofossil record from urban archaeological sites in Gdańsk (N Poland), Święta-Musznicka (et al., 2015):
    “Fruit production by S. aloides is confirmed for the 6th, 8th, 9th and 13th century …” “Based on the recent observations, we may suggest rather mild winters in this area during the early medieval period, as frost is among the most important factors limiting survival of the Salvinia megaspores.” “The climate warming could be also among the important factors forcing the expansion of Stratiotes triggered by generative reproduction. Moreover, the archaeobotanical data confirm, that around 11th to 13th [!] century, in the ruderal plant communities developing on nutrient rich habitats, several relatively thermophilous species …” “Some of these species are archaeophytes of the Mediterranean [!] and Irano-Turanian [!] origin.” (Well, well…)

    Święta-Musznicka (2011): “Our results suggest that in the Vistula deltaic area the S. natans expansion in the Early Middle Ages (7th–8th century A.D.) was similarly stimulated by climate warming, while its subsequent decline was mainly due to climate cooling, especially during the Little Ice Age.”

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