I wasn’t aware of Blog Action Day until I read about it on Rebecca’s My Adventures in History. Though the day has already passed, I was intrigued by the subject for this year, climate change. Believe it or not, one of the most sublime moments of the Lewis & Clark Expedition was due to climate change.
First the moment, from the Journal of William Clark, November 6, 1804:
last night late we wer awoke by the Sergeant of the Guard to See a nothern light, which was light, but not red, and appeared to Darken and Some times nearly obscered, and divided, and many times appeared in light Streeks, and at other times a great Space light & containing floating Collomns which appeared opposite each other & retreat leaveing the lighter Space at no time of the Same appearence.
The Corps of Discovery, by this time getting settled at their winter camp near the Mandan villages in North Dakota, had just experienced the aurora borealis, or Northern Lights.
Now the explanation (and I would love to hear stories from anyone who has seen the aurora borealis in person — I never have):
Though there is still much to learn about the incredibly beautiful natural phenomenon known as the aurora borealis, we know today that it is caused by solar flares which interact with the earth’s magnetic field. The subatomic particles of the flare are directed in streams to the earth’s magnetic poles, appearing in the sky as colorful trembling arches and streaks in a variety of colors.
There are good indications that the aurora borealis may have been especially vivid during Lewis & Clark’s time. The reason is that they lived during a period of intense sunspot activity, solar wind, and solar storms — a period known to climatologists as the “Little Ice Age. ”
From about 1400 to about 1850, the climate of Europe and North America was much colder than it is today. This Little Ice Age was marked by erratic summers, short growing seasons, brutal winters and frequent, nasty storms. Though the cause of climate change is still imperfectly understood, the Little Ice Age is believed to have been caused by changes in the sun, especially sunspot activity, and variations in the magnetic field of the earth.
This weather was more than an inconvenience. There are countless ways in which it changed history. For example, in 1612, a terrible crop failure in Scotland led King James VI to allow Scottish farmers to resettle in Ireland’s Ulster, setting the stage for centuries of religious warfare. A tremendous storm in 1634 permanently altered the coastlines of Denmark, Germany, and Holland. In 1666, an unexpected heat wave led to London’s Great Plague and Great Fire. A 1703 gullywasher in England blew down the lighthouse at Plymouth, uprooted thousands of trees, wrecked countless ships, and took 8000 lives — more even than the Galveston Hurricane of 1900, the worst natural disaster ever suffered in the United States.
The Little Ice Age also had almost unimaginably profound effects on the settlement of North America. From about 800 to about 1250, the earth had undergone a mild, warm period that, not coincidentally, marked the era of Viking dominance of the seas. From their northerly realm, the Vikings explored the coast of North America and put down settlements; eventually their colony in Greenland grew to over 3000 people. But as the Little Ice Age set in, the Viking culture of seafaring was destroyed; much of the year, their ships were trapped at home. Their North American settlers were cut off and eventually lost completely. With the Vikings out of business, it fell to the more southerly European countries–Spain, Portugal, France, and England–to colonize the Americas.
In North America, old accounts show how much more severe the winters were for our colonial ancestors than they are today. Probably everyone has read about George Washington hauling his troops across the icy Delaware River, and marveled at the incredible cold endured by his troops at Valley Forge. In early America, rivers and coastlines routinely froze over in winter, meaning the fishing fleets had to stay home and travel was awful. Our ancestors really did have to walk to school through five feet of snow, and contend with snow drifts as high as 25 feet. In 1740, Boston Harbor froze over from December through April. One man even drove a sleigh across the ice from Cape Cod to New York City!
For Lewis and Clark as for millions of other people who lived during the Little Ice Age, the cold winters and erratic weather were just what they had to deal with on a yearly basis. But the winter at Fort Mandan was one for the record books (and William Clark was right there to record it). Clark’s thermometer, which is considered reliable, routinely reached -40. After a while, as Clark wrote, a temperature of -9 “was not considered cold.” Two of Clark’s journal entries give something of the flavor of what the Corps of Discovery experienced:
Dec. 7, 1804: Capt. Lewis took 15 men & went out join the Indians, who were at the time he got up, Killing the Buffalow on Horseback with arrows which they done with great dexterity … The Thermometer Stood this morning at 1 d. below 0. three men frost bit badly to day.
Jan. 10, 1805: last night was excessively Cold the Murkery this morning Stood at 40°. below 0 which is 72°. below the freesing point.
There’s some good further reading on this topic in The Winds of Change: Climate, Weather, and the Destruction of Civilizations by Eugene Linden (2006).