Mount Tambora

"Tambora: The Eruption That Changed the World" by Gillen D'Arcy Wood explores the 1815 eruption of Indonesia's Mount Tambora that caused widespread climate change for three years. (NASA, Wikimedia Commons photo)

In Ireland, families huddled together and died by the thousands, killed by typhus and starvation. In the agriculturally rich province of Yunnan, China, some parents sold children for a mouthful of rice. In the delta of the Bay of Bengal, cholera killed without warning and then traveled the globe for decades. At Monticello in the United States, Thomas Jefferson wondered how he would ever escape his burden of debt as frosty summer mornings killed his crops.


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That there was something desperately amiss with the weather in the summer of 1816 was apparent to the literary party summering near Geneva, Switzerland. It was Geneva's coldest summer since record keeping began, its gloom interrupted only by violent storms. Mary Shelley created Frankenstein under its doleful influence, and its bleak face appears in several poems by Lord Byron, including "Darkness," inspired by a day in June when daylight fled.

I had a dream, which was not all a dream.

The bright sun was extinguish'd, and the stars

Did wander darkling in the eternal space,

Rayless, and pathless, and the icy earth

Swung blind and blackening in the moonless air …

In "Tambora: The Eruption That Changed the World," Gillen D'Arcy Wood weaves a story that Shelley and Byron could not have told, because they could not have known it. Behind the killing weather and the noonday dark was the largest volcanic eruption in recorded history. Mount Tambora, on the Indonesian island of Sumbawa, is one of a necklace of volcanoes studding the seismically active "Ring of Fire," which extends from the tip of South America, up the western coast of two continents, across the Bering Strait from Alaska, and then back south through Japan, Indonesia and New Zealand.

The account of Tambora's 1815 eruption is global climate change in an eyedropper. This single event changed global temperatures, tampered with the ocean circulation patterns that drive weather, and created conditions favorable to epidemics that took decades to resolve. It upended economies and uprooted millions. It is an object lesson of what today's atmospheric carbon buildup may yield.

Wood, a professor at the University of Illinois at Urbana-Champaign, doesn't shy from the parallels between what we face today and Tambora's disruption, but the book is no polemic. Our climate, instead, serves as a backdrop. The warning is clear: The climate aftermath of Tambora lasted only three years, the disease and desperation it birthed stretched out far longer; there is no sign that we'll get off so easily or so quickly. His telling of this single climate incident gives body to all the abstraction in today's statistics about atmospheric carbon, and brings any warnings down to human scale: the crowds of beggars in France, the food riots in Germany, New England schoolchildren caught barefoot in a June snowstorm.

The disaster is immediate and brutal on Sumbawa. Nearly 200 years ago, at around 7 p.m. on April 10, 1815, three columns of fire roared up from Tambora's twin peaks in a blast heard hundreds of miles away. Torrents of hot wet ash fell like rain, followed by a hail of pumice stone. Hot molten rivers, some 16 feet high, flowed from its twin peaks, eventually extending over a 348-mile area. Hurricane-force winds uprooted trees, forests and villages turned to ash, and finally the volcano's conic shell imploded and Tambora sank, nearly a mile of its height gone, leaving a 4-mile-wide caldera, or crater. Two days of darkness settled over the entire region as the ash cloud extended some 373 miles high.

Tambora's ultimately global reach is testament to its size and eruptive force, Wood explains. Volcanic material must penetrate the stratosphere to have such an impact. Tambora's ejecta punctured it by more than 25 miles and then spread more than 600,000 square miles, "an aerosol umbrella six times the size of Mount Pinatubo's 1991 cloud," Wood writes.

The heavier material quickly fell back to earth with the rain, but water vapor, sulfur molecules, fluorine gas and the finest ash particles underwent chemical changes that led to a 100-megaton sulfate aerosol layer.

And here's where the real trouble begins. In 18 months, this layer passed over both poles, leaving a signature read today in polar ice cores. As this "global veil" encircles the planet, it bounces solar radiation back into space while allowing the earth's heat to escape. The results are depressed temperatures around the world — lower by as much as 5-6 degrees Fahrenheit in some regions, although barely changing others. While much of Europe and the Eastern United States suffered through drastic climate impact, neither Russia nor the United States west of the Appalachian Mountains were affected.

Wood makes compelling use of literature as a stand-in for the voiceless throngs crushed in this disaster. Along with Byron and Mary Shelley — constant companions in this narrative of events — there is Irish writer William Carleton, poet John Keats, Percy Bysshe Shelley, and briefly Samuel Taylor Coleridge, who called the summer of 1816 "this end of the world weather."

These voices are essential, Wood explains. "In the aftermath of a mega-disaster such as Tambora, the paucity of victim narratives itself tells us something both of the scale of the cataclysm and who bore the brunt of it: the poor and illiterate peasant millions of the early nineteenth-century world."

But nowhere is the poet's voice more affecting than in the story of Tambora's devastating march through the once rich, temperate agricultural province of Yunnan in southwest China. The poet is Li Yuyang, and unlike the poets of England, he had no shield against the disaster's effects; he was crushed by them. Li Yuyang had been a scholar, hoping to make his way in the Confucian meritocracy, when his family's bankruptcy forced him to return home and take to the land.

His poetry has not before appeared in English. It combines stark observation of the collapse around him with wrenching personal details. In the poem "A Sigh for Autumn Rain," he writes of a downpour so steady that homes are destroyed.

People rush from falling houses in their thousands …