The start of the Ontake-san eruption, September 27, 2014.

Yesterday’s news out of Japan was the unexpected eruption of a volcano. Hikers – some of them weekend strollers taking pictures of fall colours – were overtaken when the sleeping volcano expelled its nasty breath. Witnesses said that they thought the explosion was thunder. The idea that the quiet mountain might be active was a remote thought. But ash soon piled a metre deep. And at least 30 people are dead.

Volcanic ash at Ontake, Japan.

The central Japan volcano, Ontake-san, is the second highest in the country. The 3,000-metre mountain was calm enough to encourage hundreds of weekend walkers to enjoy the trek along trails and up concrete steps to the rim of the mountain. But the volcano’s sudden expulsion of ash created a mad scramble to get off the volcano. Dozens of hikers near the top were overcome by the ash. On Sunday, the rescue operation involved more than 500 troops, police officers and firefighters who searched for injured survivors and whisked them away by helicopter.

This unexpected tragedy was localized – one puff of ash on one mountain in one country. It will not have environmental consequences around the globe. It is hard to imagine that any volcano can affect weather a hemisphere away, but such things have happened.

Nearly two hundred years ago (in April, 1815), the largest eruption in at least 10,000 years did change the world’s climate. Millions of tonnes of ash were expelled from the Indonesian volcano Tambora. Its ashes encircled the globe, causing havoc by shading and cooling the planet. The dust was suspended in the sky for months, concentrated in a cloud drifting over North America where it created “The Year without a Summer” in 1816. In the United States, late spring frosts killed crops.

For weeks, the sky was shrouded by a red fog, making daylight dark. Ice was reported on Pennsylvania rivers and lakes in July and August. Crop failures inflated food prices. Corn increased from 12 cents a bushel to nearly a dollar. Temperatures dropped to minus thirty in New York City that winter. Directly due to the big chill, Vermont’s population dropped by 15,000 people (substantial in those days). Among those who left Vermont were the family of Joseph Smith, who moved from Sharon, Vermont, to Palmyra, New York. Had his family never moved, Smith would not have found the golden tablets buried near Palmyra, the tablets would have gone untranslated, the Book of Mormon would not exist, and today’s 15 million Mormons would all be Southern Baptists. Prompting us to think that perhaps the god Elohim left his home planet Kolob just long enough to visit Earth, explode the volcano, change the climate, and put the Smith family on the road. Might have been easier for him to have just planted the tablets in Vermont.

Built on a rainy day out of volcanic ashes.

The Tambora ash cloud drifted onwards to Europe, resulting in disaster for wheat, oats, and potato crops. Riots and looting broke out as desperate people pillaged grain houses. The veil of ash continued to block the sun. There were famines in Wales, failed monsoons in China, an ice-dam break in Switzerland. In June 1816, non-stop rainfall forced Mary Shelley, John William Polidori, and their friends to stay indoors for much of their Swiss holiday. To pass time, they had a contest to see who could write the scariest story. Shelley wrote Frankenstein and Lord Byron wrote “A Fragment”, which Polidori later used as his inspiration for The Vampyre — a precursor to Dracula. All of this was the result of a single volcanic eruption in Indonesia — and the boredom of a group of storm-stayed young people.

Can anything good come from a volcano? Other than stories like Frankenstein and Dracula? Well, volcanic ash, rich in potassium, helps farms do well on the slopes of volcanoes. Near Pompeii, pumice from volcanoes was used as paving stones. Islands grow from the sea (think Hawaii). But far more importantly, the Earth’s environment was originally shaped by volcanoes. Life as we know it would not exist, except for belching volcanic gases that saturated the atmosphere with carbon dioxide, leading to plants which, in turn, converted most of that CO2 into O2.

However, Japan’s Ontake-san (-san means both honourable and mountain, depending on context) is unlikely to either change the climate or inspire horror literature. It will probably remain a local tragedy, a sad and somber time for the friends and families of the casual weekend hikers who were overcome by one brief puff of ash from one of Earth’s many unremarkable volcanoes.