Two hundred years ago, on the evening of April 5, 1815, a volcano known as Mount Tambora on an island in Indonesia began erupting. The explosion was heard 1,600 miles away. Even 800 miles away on Java, Stamford Raffles thought it was cannon fire. It kept erupting until April 10 when it exploded. William Klingaman and his son, Nicholas Klingaman, write in "The Year Without Summer":

Propelled by the force of the eruption, gray and black particles of ash, dust, and soot rose high into the atmosphere, some as high as twenty-five miles above the crumbling peak of the mountain, where the winds began to spread them in all directions. 
The eruption was the most powerful in recorded memory, 10 times more powerful than the more famous Krakatoa, a hundred times stronger than Mount St. Helens. Thousands died immediately from breathing the ash, or drinking the water; thousands more from starvation, totaling nearly 90,000 deaths in Indonesia. But that was just the beginning. The Klingamans write:
In addition to millions of tons of ash, the force of the eruption threw 55 million tons of sulfur-dioxide gas more than twenty miles into the air, into the stratosphere. There, the sulfur dioxide rapidly combined with readily available hydroxide gas — which, in liquid form, is commonly known as hydrogen peroxide — to form more than 100 million tons of sulfuric acid. 
The cloud spread around the world and caused global temperatures to drop 2 degrees Celsius, or about 3 degrees Fahrenheit. That doesn’t sound like much of a change, but in fact, it’s a massive change, and it caused the Year Without Summer in 1816, and it stayed abnormally cool for almost a decade. Crops failed, people starved and rioted, diseases ran rampant, rivers froze. April was cruel; A snowstorm started on April 12 that buried Quebec City in four feet of snow. That was just the start. In August, Thomas Jefferson wrote: “We have had the most extraordinary year of drought and cold ever known in the history of America.”

Three degrees. That's all it took to starve thousands, cause migrations that moved tens of thousands from New England to the Midwest and cause riots and revolution in Europe. Drought dried out the forests and fires raged across the Northeast. Three degrees. Think about that the next time someone says that climate change isn’t a big deal.

Laufmaschine

Put on pedals and you have a bike. (Photo: Public Domain)

At least one good thing came out of this climate disaster: The bicycle. A commenter on TreeHugger tells us:

Baron Karl von Drais needed a means of inspecting his tree stands that did not rely on horses. Horses and draft animals were also the victims of the "Year without Summer" as they could not be fed in the great numbers that had been used. Drais discovered that by placing wheels in a line on a frame one could balance through dynamic steering. Thus a narrow vehicle capable of maneuvering on his lands-the Laufsmaschine became the immediate precurser of the bicycle.

Lloyd Alter ( @lloydalter ) writes about smart (and dumb) tech with a side of design and a dash of boomer angst.