The Year Without a Summer

The Year Without a Summer

The winter of 1815—16 was no different from any pervious winter in southern Canada and the northeastern United States. Spring's arrival was normal; by April birds had returned from their wintering grounds and flowers had given color to the brown earth. But this was to become a most famous year, because it was the year without a summer.

April is often a cold month in the northeastern United States and southern Canada, but by May of 1816 the temperature still had not risen, and people became concerned. Morning after morning frost covered the ground as winter hung on.

On June 5 cold winds lashed the area, followed by a heavy snowstorm that covered the countryside with nine to twelve inches of snow. Freshly shorn sheep froze to death. The corn crop failed, and only the hardiest grains and vegetables survived. On June 6, at the inauguration of Governor William Plumber of New Hampshire, it was so cold, as one witness recalled, that "our teeth chattered in our heads, and our hands and feet were benumbed."

Weird weather continued into August with early morning temperatures always in the low thirties. On a few afternoons that were warm, people gamely tried to plant crops, only to have them destroyed by frost and snow. A killing frost occurred in mid—September; the new winter was slightly early, and it was to be unusually severe.

The spring and summer of 1817 returned to normal, and the weather has been predictable ever since. What caused the year of no summer? Many theories were proposed, but none even came close to the truth. A few scholars of the day suggested that an outbreak of sunspots had caused the chill.

The scholars of 1816 had no way of determining the actual cause of the extended winter, but the crackpots of the day presented explanations without hesitation. One outstanding theory of the prophets of doom was that it had been caused by Benjamin Franklin. Several proponents of this hypothesis were able to explain exactly why. The most commonly believed theory was that the hot interior of the earth releases heat into the atmosphere but that because of Franklin's newly invented lightning rods, which were being installed all over the country, the earth's process of releasing heat into the atmosphere had been interrupted. This resulted in cooling of the air, and the summer season of 1816 was missed entirely.

Not all thinkers of the day accepted that theory, but a runner—up explanation also blamed Ben Franklin. Its followers were firmly committed to the idea that, since lightning is heat, it must follow that the lightning rods had taken the heat from the air — hence, no summer!

It seems ironic that as early as 1784 Benjamin Franklin had shrewdly speculated that dust from volcanic eruptions could affect climates by blocking out sunlight. He had made a connection between a constant "dry fog" in the atmosphere and the unusually cold winter of 1783—84. And he was right.

After many years of speculation and research, scientists now know the cause of the year without a summer. The event took place a year before and half a world away, in the Dutch East Indies. On the night of April 5, 1815, Mount Tambora, located on the island of Sumbawa, erupted with a force unmatched in recorded history. This gigantic eruption was even more powerful than the famous explosion of Krakatau that was to occur sixty—eight years later.

Tambora ejected over twenty—five cubic miles of debris that blasted nearly a mile off the top of the 13,000—foot volcano. It carpeted islands hundreds of miles away with layers of volcanic ash well over a foot thick. The fine dust rose so high into the stratosphere that it encircled the world for years to come. The net effect was to screen out sunlight and cause a drop in temperature, especially in New England and Canada.

The volcanic dust in the atmosphere affected other parts of the world as well as North America. In fact the chill was almost worldwide. Crop failures in Western Europe caused widespread famine, and many people starved to death. In Switzerland people were reduced to eating Iceland moss and cats, and food riots broke out in France. Had this unseasonal drop in temperature continued for a few more years, continental ice sheets would have started to form and the earth could have slid into a new Ice Age.

A number of scientists predict that such wintry summers could occur again. Nature's volcanism and human industrial activity have caused a steady buildup of dust in the atmosphere over the last few decades. If this trend continues for about a century, it could produce an effect opposite to that of the greenhouse. World temperatures would be lowered significantly and an age of ice would return.

From the book: 
Our Fascinating Earth