Sunday, 11 May 2014

Climate change: the ice age kind

The Thames and London Bridge in 1677
The Little Ice Age, from about 1317-1800, began with catastrophic floods, crop failure, and domestic animal deaths (which brought on economic depression), harsh winters—and starvation. Epidemics raged unchecked, and millions died in the bubonic plague outbreak in 1348-1350. Because so many laborers (peasants tied to the land, who owed service to their landlords) died, cathedral and castle building ground to a halt for years. 

Our ancestors survived conditions with considerably less resources than we have available. There was no central heating in their homes and shops, of course, and fuel (peat, coal, and wood) was just as expensive, or more so, as the fuels we consume today. Most people just couldn’t afford the luxury of warmth in winter. They didn’t often change clothes or bathe in cold weather when they’d have to haul and heat water. There are paintings from the Netherlands that show women standing in a wide, shallow bowl while washing their legs with a cloth. Lower-economic class families and their guests shared beds near a kitchen hearth, or shut themselves into heavy curtains or a cupboard bed to capture body heat. Portraits of well-to-do families show heavy velvets and furs on men and women. While that certainly shows status, the sheer weight of the clothing indicates that they were needed for warmth.

Family size burgeoned during the global temperature dip of the 16th and 17th centuries: maybe the long, freezing nights were not all that boring! It didn't hurt that the Puritans took the "Be fruitful and multiply" command from Creation very seriously.  

Of course our ancestors knew nothing about it, but they experienced the effects of a plunge in sunspot activity in the 1600s, which corresponded with the coldest years of the Little Ice Age. Specifically during Mary Dyer’s* lifetime, 1611-1660, it was the time of famines, waves of bubonic plague across Europe, the Thirty Years War, the Great Migration to America, the English Civil War, and the explosion of the slave trade to the Americas and Europe. 
Iceland surrounded by sea ice and icebergs, late 17th century

Iceland’s ports were ice-bound by miles, year-round for several years, and trade and passenger shipping from Europe was forced far south to avoid sea ice. On America’s east coast, there were harvest failures, starvation, epidemics of smallpox and yellow fever, and pest plagues. Boston Harbor's sea water froze over for more than a mile out, hard enough to walk on, for two weeks at a time. See "Boston snowpocalypses of 1638". 

The few passenger ships that made an Atlantic winter crossing had to ride at anchor in Massachusetts Bay until the harbors thawed and boats could ferry passengers to the docks. (And you know that those ships didn’t have central heating.)The weather was extreme in the summers, too: the hurricane that made landfall between Plymouth and Boston in 1635 is considered to be the strongest ever to hit New England, based on reports of tidal surge and millions of trees felled by the winds and tornadoes.

It seems that New England was the victim of a polar vortex in 1638 and many other  years.

 Journal of Governor John Winthrop—January 1638:

“About thirty persons of Boston going out in a fair day to Spectacle Island to cut wood, (the town being in great want thereof,) the next night the wind rose so high at N.E. with snow, and after at N.W. for two days, and then it froze so hard, as the bay was all frozen up, save a little channel. In this twelve of them gate to the Governor’s Garden [an island], and seven more were carried in the ice in a small skiff out at Broad Sound, and kept among Brewster’s Rocks, without food or fire, two days, and then the wind forbearing, they gate to Pull-in Point, to a little house there of Mr. Aspenwall’s. Three of them got home the next day over the ice, but their hands and feet frozen. Some lost their fingers and toes, and one died. The rest went from Spectacle Island to the main, but two of them fell into the ice, yet recovered again. In this extremity of weather, a small pinnace was cast away upon Long Island [in Boston Harbor] by Natascott, but the men were saved and came home upon the ice.” 

The Little Ice Age “peaked” in the years of the Great Migration from England to the American colonies, and during the English Civil Wars of the 1640s—the coldest years in many centuries. 

This graph shows the severity of winters in
Europe and North America from 1000-2000 AD.
The absolute coldest period was from 1600-1675.

When Mary Dyer was making a winter trip back to America after several years in England, her ship diverted to Barbados because of severe storms. From a letter written in Barbados on Feb 25, 1657:
“A ship came in hither, which was going to New England, but the storms were so violent that they were forced to come hither, [until] the winter there was nearly over. In this ship were two Friends, Anne Burden of Bristol, and one Mary Dyer from London; both lived in New England formerly, and were members cast out of their [Puritan] churches. Mary goes to her husband who lives upon Rhode Island...”  

London Frost Fair, 1684
Click to enlarge
In the winter of 1683-84, there was another period of extreme cold where the wide and shallow River Thames froze above the London Bridge. At that time, the bridge, which was dismantled in the 19th century, dammed most of the ice to the west, and the river froze solid. (Now, of course, there’s a deep and fast current contained between the embankments.) The novelty of the frozen river drew thousands of people to play and skate, and slide around, and of course, the more reckless broke bones or died of their injuries. Horses drew carts, tents were erected for food vendors, and whatever one bought for three pence on the shore cost four pence on the ice. With long, frozen winters with little heat and light, it must have been a very gloomy existence. So when the Frost Fairs set up on the frozen Thames, there was, in a relatively small area, entertainment, recreation, shopping, people-watching, and foods and beverages they wouldn’t consume on a daily basis (think of today’s deep-fried junk foods at fairs).  

 A NASA website says, 

“During the coldest part of the Little Ice Age, from 1645 to 1715, there is believed to have been a decrease in the total energy output from the Sun, as indicated by little or no sunspot activity. Known as the Maunder Minimum, astronomers of the time observed only about 50 sunspots for a 30-year period as opposed to a more typical 40-50,000 spots. The Sun normally shows signs of variability, such as its eleven-year sunspot cycle. Within that time, it goes from a minimum to a maximum period of activity represented by a peak in sunspots and flare activity.”

More from NASA: 

“Between the mid-1600s and the early 1700s the Earth’s surface temperatures in the Northern Hemisphere appear to have been at or near their lowest values of the last millennium. European winter temperatures over that time period were reduced by 1.8 to 2.7 degrees Fahrenheit (1-1.5 Celsius). This cool down is evident through derived temperature readings from tree rings and ice cores, and in historical temperature records, as gathered by the University of Massachusetts-Amherst and the University of Virginia.”

Could a Little Ice Age happen again? Scientists say that after the current sun cycle, we’re heading for a “grand minimum” in approximately 2020, that would last until about 2070 (don’t worry—be happy—we’ll be dead by then!). A May 2013 article says the slight cooling effect of the sun’s decreased radiation would only slow, but not stop, global warming. Yes, an ice age could happen again. But not one that we’ll ever see.

  Christy K Robinson is author of two biographical novels on William and *Mary Dyer, and a collection of her nonfiction research on the Dyers. In 1660, Mary Dyer was hanged for her civil disobedience over religious freedom, and her husband’s and friends’ efforts in that human right became a model for the United States Constitution’s Bill of Rights 130 years later. The books (and Kindle versions) are available on Amazon. CLICK HERE for the links.

No comments: