The Year There Was No Summer

On April 10, 1815, Mount Tambora on Sumbawa, in what is now Indonesia, erupted with a force estimated at roughly 100 cubic kilometers of ash and rock. It is the largest volcanic eruption in recorded history. The mountain lost a third of its height. The caldera it left is six kilometers across.

The ash took a year to spread around the globe and drop the Earth's average temperature by about half a degree Celsius. In Europe and North America, 1816 came to be known as the Year Without a Summer — or, to New England farmhands, 'Eighteen Hundred and Froze to Death.'

Frost killed crops in June. Hay prices in New Hampshire tripled. Oats, the main fuel for working horses, failed across the northern United States; some farmers slaughtered their teams because they could not feed them. In Switzerland, floods and famine drove hundreds of thousands onto the roads. At a rented villa on Lake Geneva that summer, trapped indoors by weeks of storms, Mary Shelley, Percy Shelley, and Lord Byron held the ghost-story challenge that produced Frankenstein and the first English-language vampire novel.

Chinese provincial records note dead water buffalo in Yunnan, where the rice crop froze twice. The Indian monsoon broke, and a cholera outbreak in Bengal — previously regional — pushed out along disrupted trade routes into the first global pandemic of the disease.

Karl Drais, a forest official in Baden, was left with a country full of dead horses and a practical problem. His proposed solution — a two-wheeled wooden running machine, patented in 1817 — is the direct ancestor of the bicycle.