By Tamie Dehler
TERRE HAUTE — In the past, I’ve written about how different religious movements and economic crises affected our ancestors. The same argument can be made for weather. What does weather have to do with genealogy? Perhaps more than we think.
In 1595, a minister named John King wrote, “Our years are turned upside down; our summers are no summers; our harvests are no harvests.” Something was happening to the earth which greatly affected our ancestors. The temperature was getting colder.
The Little Ice Age was a period of about 400 years in which the temperature of Europe and North America was colder than average. It started around 1450 and lasted until about 1850. It had it ups and downs within this long period with the coldest intervals being in the 1600s and the 1700s. Estimates are that the temperature was down by about 2 degrees Fahrenheit at the coldest points.
First let’s look at what was happening in this time period. Medieval Europe had enjoyed a warm period. It looks like the same was true for North America. This mild period of 1000-1400 allowed Norse explorers to settle Greenland. But beginning in the late 1300s, warm summers started becoming less dependable. By the mid-1400s things were worse. The tree line in the Alps gradually lowered as glaciers grew and advanced. This led to some of the higher alpine villages being covered and obliterated. The production of grapes, which was common in England, northern France, and Germany in Medieval times ceased. Fishermen reported large amounts of sea ice in the North Atlantic. Eskimoes were spotted kayaking off the cost of Scotland.
Winters were harsh and rivers and bays that had previously never frozen, did freeze up. This includes the Thames in England and New York harbor. The growing season became shorted by up to three weeks. Crop yields were inconsistent and low. This led to less livestock production and famine. Some farms and even villages were abandoned. People who were fighting to survive famine were even more vulnerable when the Black Death (bubonic plague) came along in about 1350. In Greenland, the Norse settlements died out due to a lack of food production by 1400.
In a time without thermometers and temperature record keeping, scientists have discovered and studied the Little Ice Age through different methods. Writers of the time described the harsh weather. Paintings of the period (especially from 1565 to 1665) depicted many winter scenes, and the painted skies showed significantly more cloud cover as the percentage of open sky decreased. Tree-rings and ice core samples taken back to this time show that trees were growing slowly and ice was mounting during these years.
What caused the Little Ice Age? There are several theories, but most say it was a combination of events. During this time there was a near absence of sunspot activity on the sun (this means the sun is emitting less energy and heat to the earth). Then, as more snow fell and glaciers enlarged, these white areas reflected the sun’s rays away from the earth causing increased cold. Another theory involves carbon dioxide, the greenhouse gas. As large populations in Europe died due to the plague, their farmlands and villages went back to forest. More trees means that more carbon dioxide was being taken out of the atmosphere (a good thing in 2009, but maybe not so good then), and this could have contributed to the cooling effect. Another factor could have been an increase in volcanic activity. Volcanoes spew their gasses and ash into the atmosphere and this, like industrial pollution, blocks the sun’s rays.
Next week we will discuss the year without a summer.
