Tambora the volcano that changed the world: two hundred years ago, the eruption of a volcano in present-day Indonesia caused a three-year climate crisis that threw the world into chaos and changed history in ways big and small.

• Author: Wood, Gillen D'Arcy
• Position: TIMES PAST 1815

Americans in New England shivered through summer snowstorms. In Europe, starving families drank the blood of their cows to survive. In Asia, a new strain of cholera gripped India and began making its way around the world, ultimately causing millions of deaths.

No one knew it at the time, but these and other global calamities that began happening in 1815 were all traceable to a single unlikely source: the eruption of a volcano named Mount Tambora in present-day Indonesia.

In its immediate aftermath, the Tambora eruption-200 years ago last spring--wiped out 100,000 people on the region's islands, giving it the sinister distinction of the deadliest volcanic eruption in history. But it's Tambora's second life--as a planet-cooling aerosol cloud--that had far more dire effects on the world. Those climate changes, which disrupted societies everywhere, led to famine, disease outbreaks, and mass migrations. At the same time, Tambora also inspired new ideas in some artists, helping to spawn, for example, two of literature's most famous monsters (see box, p. 21). Today, Tambora stands as a reminder that environmental changes can have sweeping--and unanticipated--effects.

The 'Ring of Fire'

Part of the Ring of Fire--a horseshoe-shaped string of roughly 450 volcanoes surrounding the Pacific Ocean (see map)--Indonesia is accustomed to angry volcanic eruptions. More than 75 percent of the world's active volcanoes sit along the Ring of Fire, which includes parts of South America, North America, Japan, and Southeast Asia. But the force of Mount Tambora's eruption and its scale of destruction was something that neither Indonesia, nor the rest of the world, had ever seen.

At 14,000 feet above sea level, one of the tallest peaks in the Indonesian archipelago, Tambora had been mostly dormant for 1,000 years. But deep inside its volcanic chamber, churning magma, heat, and pressure had been building for 5,000 years and was ready for release. The first eruption, a relatively small one, came on April 5,1815. Then, on April 10, when the volcano had seemingly calmed, the big one hit.

At 7 p.m., a massive plume of volcanic gas and rock shot miles into the sky, decapitating Tambora's peak. Waves of lava spilled down the mountain into the sea, and trees flew like toothpicks in the volcanic whirlwind. Within an hour, tens of thousands of people on the Indonesian island of Sumbawa were dead. Tsunamis crashed into neighboring islands, and the volcanic plume cast a pall of darkness across all of Southeast Asia for a week. Birds fell silent, stunned by the absent sun.

Cholera & Opium

The force of the eruption propelled the massive plume beyond the atmosphere and into the cold, dry stratosphere, eventually forming a giant stream of sulfate aerosols long enough to encircle the globe. In a matter of weeks, the stratospheric cloud circled the Earth at the Equator, causing spectacular sunsets-- splashes of orange, purple, and red--that influenced the works of artists like J.M.W. Turner, a renowned British landscape painter. The cloud then traveled on a multiyear, slow-motion journey toward the North and South poles, wrapping the Earth in a veil of volcanic dust that blocked much of the sun. Across the globe, temperatures plummeted, killing crops, spawning and spreading disease, and throwing the world into chaos.

For three years following Tambora's eruption, to be alive almost anywhere in the world meant to be hungry. People in New England nicknamed 1816 "The Year Without a Summer," or "Eighteen-Hundred-and-Froze-to-Death." Germans called 1817 "The Year of the Beggar."

The changed weather systems made it possible for certain diseases to thrive. In India, from 1816 to 1817, Tambora's eruption disrupted and delayed the Indian monsoon--the largest, most dynamic weather system in the world. The impact of severe drought followed by floods in the Calcutta region altered the ecology of the Bay of Bengal, breeding a new strain of cholera that spread across the world. By 1832, when it reached the U.S., the death toll worldwide stood in the millions.

Tambora's weather havoc is also responsible for the rise of the opium trade in China. Cold temperatures and rain devastated rice crops from 1816 to 1818 in southwest China, sinking the population of Yunnan into a devastating famine that killed thousands. A poet named Li Yuyang described the suffering in his village: "Outside, the starved corpses pile high / While in her room the young mother / Waits upon her child's death."

But even more consequential in the long term was the response from Yunnan farmers: To ensure their own survival...