The myth of Europe’s Little Ice Age

[NickB79]

http://www.voxeu.org/article/myth-europe-s-little-ice-age

The Little Ice Age is generally seen as a major event in European history. Analysing a variety of recent weather reconstructions, this column finds that European weather appears constant from the Middle Ages until 1900, and that events like the freezing of the Thames and the disappearance of English vineyards have simpler explanations than changing climate. It appears instead that the European Little Ice Age is a statistical artefact, where the standard climatological practice of smoothing what turn out to be white noise data prior to analysis gives the spurious appearance of irregular oscillation – a Slutsky Effect.

If true, this would be mind-blowing.

[enlightenment]

1. I wonder if the

people who owned the frozen vineyards and the people who set up the ice fairs on the Thames considered it a statistical artefact? Or the Arctic people who had to start hunting seals because the whales couldn't reach the frozen Arctic ocean? Or the farmers in Norway who had to watch glacial ice cover their homes and land?

The simpler explanation is that it was bloody cold - statistical evidence or not.

[caraher]

3. Did you read the article?

They do address some of these kinds of points:

The freezing of the Thames – which for most people is the most salient fact about the Little Ice Age – was caused by Old London Bridge, whose twenty arches effectively acted as a dam, creating a large pool of still water that froze twelve times between 1660 and 1815.

Tidal stretches of the river have not frozen since the bridge was replaced with five-arched one in 1831 – even during 1963, which was the third coldest winter since records begin in 1660 (after 1684 and 1740).

Grape growing in England was uncommon in the eleventh century – a lot of confusion stems from mistaking the word vivarium (fish pond) for vinarium (vineyard) – and disappeared entirely after Bordeaux passed to the English crown in 1152, suggesting that comparative advantage may have played a larger role than climate.

Similarly, the decline of wheat and rye cultivation in Norway from the 13th century may owe more to lower German cereal prices than temperature change.

[enlightenment]

4. I read the article.

There is a whole lot of "may" in the author's text - something "may" have been caused by . . .

The only certainty they present is the Thames, (and that isn't new - hell, the idea of the bridge being relevant to the freezing was mooted two years ago in the Daily Mail, of all places). The river froze over twenty times between the 14th and 19th centuries - and every single time it did, it was cold. Very cold.

Are you arguing with the fact that it was colder than was usual? First hand accounts suit me better:

In the year 1742, in the middle of August, his Majesty’s representative and the judge went to observe the areas which had been destroyed by the glacier. A measurement was made from the glacier to the nearest house, and this distance was then 200 feet. On the same day next year, 1743, the glacier had not only moved forward these 200 feet, but it also increased in width and had pushed away the houses and tumbled them around. The ice had also plowed up large amounts of soil and gravel and large rocks and crushed these rocks into small pieces which are still visible. The owner of the farm had to leave his house in a great hurry to try to find another place to stay. His farm, named Nigard, was destroyed together with all its fertile land, and the glacier had also approached other areas during the following years. The farm Bjerkehougen lost cultivated land so that only the houses were left, and it is not possible to live there any more. However, we have noted that the ice has retreated since 1748 but only very slowly. In addition to the destroyed arable land the glacier is also harmful because it produces cold winds so that rime on the ground is not unusual during the summer.

pubs.usgs.gov/pp/p1386e/norway.pdf

The Domesday book establishes the presence of 46 vineyards in England. Most of them were new plantings. They did not "disappear entirely" for quite a long time after 1152 - William of Malmesbury mentions wine from Glastonbury in the 12th century and Rabelais mentions English wine in the 15th century. What is more interesting than the evidence for its continued production is the evidence of when it stopped - with writers of he 17th-19th century commenting on the change in climate (it got colder).


Look, the article is interesting, but it relies too heavily on statistical analysis to be taken seriously. Unless you're a statistician and give all your faith to charts and graphs. I prefer a more rounded set of evidences from a variety of sources.

[caraher]

5. OK

I asked because it wasn't clear whether you'd seen their remarks on the Thames and wine making.

I think to some degree you and the authors are talking at cross-purposes. Their main point is statistical in nature (i.e. is there evidence that there is anything beyond random fluctuation behind the cold years) and doesn't deny that there were indeed some extremely cold years. Explaining in detail events commonly associated with the Little Ice Age isn't their aim, and establishing that the cold years within that span need no explanation beyond chance doesn't imply that the cold did not have important effects (which is more your focus, defending that causal link). Nevertheless, the question will arise, "If this was "normal" why did these events happen?" and they are pointing out that cold weather is not the only factor involved in many of these - and in some cases those other factors may be more significant than most people tend to think.

I'll add that I don't really know whether even their statistical point is correct. I just thought there was potentially more to it than your previous response gave credit for.

[enlightenment]

6. Ok.

If I am understanding you correctly, you are saying that the authors are disputing the idea of a "little ice age" as an event, which seems like an odd focus on terminology alone.

I'm not sure how important it is to say, "there was a span of particularly cold weather that created conditions for xxx events" versus "there was a span of particularly cold weather that we refer to as a "little ice age" . . ."

As far as their pointing out that the weather wasn't the only factor involved; in that I'm afraid they did a poor job, which is really what set me off. It is poor scholarship to opine that there were other influences and then preface those influences with "may have" - because if they "may have" had an influence, they might also "may not have" had any influence at all.

Hoofbeats suggesting horses, not zebras - if a glacier eats a farm in Norway during a period of colder than normal weather, it is reasonable to assume that the reason the farmer stopped selling corn is because of the larger than usual glacier - not falling corn prices.

[Demeter]

2. The myth of data reconstruction, more likely

I wouldn't hang a dog on the evidence