I've seen lots of speculation about this, but very little in the way of hard data. I would be most interested in a brief overview of this phenomenon- Is it fact? What are the dates? What was the general global impact? When did a warming trend begin? Anything you care to share would be great.

Thanks-

I just watched a program about the lost Viking colony in Greenland. Their best scientific explaination for their disappearance is this mini ice-age. According to the program, they beliveved it was during the late 15th and early 16th century.
The name of the program was Secrets of the Dead. It had some fascinating information about Viking culture of that time period. The most interesting was how religion may have played a role in their downfall.

Starting in the middle (i haven't really looked at the previous chapter yet), lets take as accepted that 1100-1300 was quite toasty, at least in Northern Europe.

Apparently, things started getting bad in the Arctic regions first, with growth of ice starting around 1200. By 1350, things were getting pretty bad in Greenland, ships needed to change course between Europe and Greenland due to ice, and the West Settlement (Vesterbygd) was destroyed by disease or something. Iceland was also struck suddenly by cold around 1200, which got worse until around 1300, and there were later cold 'spells' from 1580-1700.

Europe first started seeing effects in the 13th cent, in the form of nasty storms with huge floods, especially along the North Sea. Loss of life at some of these floods were upwards of 100,000 dead (estimated). In England, the ports of Ravenspur and Dunwich were gradually lost to storms. Large flood events were recordeed in 1421, 1446, 1570, 1240, and 1362. The most storms occurred in the early 15th cent and late 17th cent. These types of storms are common when there is either a rise in sea level or when a colder Arctic region messes with stuff. Blown sand was also a problem, with ports and towns on sandy coasts (denmark, Brittany to the Hebrides) getting totally covered with massive dunes. Around 1400, a port in Wales, Harlech, was eaten by a line of giant dunes.

Cooling began in Europe starting around 1300, and it looks like a gentle downward curve, which heads down until the mid 15th cent. This was accompanied with very wet summers around 1313-1321, which occurred after a spell of warm, dry summers from 1284-1311. This was when there were nasty famines, disease epidemics among both people and livestock. In western Europe, the rest of the 14th cent was highly variable, with the 1320s, 1330s, and 1380s having warm, dry summers (rather droughtish), and the rest of the time (esp the 1360s) with wet summers. Eastern Europe seems to have had an excess of dry, warm weather, with lots of drought. The 1430's had a spell of very harsh winters in central and western Europe, as well as 1407-8 and 1422-3. The ice allowed traffic to cross the Baltic, and possibly also the North sea from Norway to Denmark.

The alteration in climate affected agriculture, with the destruction of northern vinyards, a southward retreat of corn production, and depopulation of villages. There are some numbers here on village desertion that I can quote if you are interested. Most desertions in England took places between 1430-1485, "which coincides with a fairly well-documented time of frequent cold winters and wretched summers, the latter particularly in the 1450s and later 1460s". Norway was the worst hit, and also Denmark. Wheat, which requires a hotter summer than other cereals, declined in favor of barley and oats, and rye. "there were many places where cereal growing ceased to be profitable and was given up in favor of sheep rearing to meet the increasing demand for wool."

In southern europe, there is little evidence of severe effects from 1420 to 1480.

Looking at some of the charts, it seems as tho the climate bottomed out in the mid 15th, and then in the late 15th there was an upswing, followed by a relatively pleasant period from 1500-1550, probably similar to the early 18th cent. But around 1550, there was a sharp change, followed by the coldest period since the last ice age, 10k years ago. And hence, stuff like Bruegel's "Hunters in the Snow" (1565). The late 17th cent was apparently pretty nasty.

This sort of data comes from:
Annals, chronicles, audited account books, other similar documents
river flood levels
tree rings
lake bed sediments
ice sheets
glacier movements
isotope measurements on tree rings and sediments
pollen analysis
insect populations
grain prices

And a note from me-
realize also that a temperature change (climactically) does not necessarily mean that every day (or even every year) was X degrees colder. Most temperature avergae changes (recently) are on the order of 1 or 2 degrees C at most. But it can mean different overall weather patterns, like if New England were to switch from a pattern where cold Canadian air was sucked down here to one where wet, warm Gulf of Mexico air was predominant.