The Tambora eruption of 1815
At seven in the evening on April 10, 1815, the Tambora volcano on Sumbawa Island in Indonesia unleashed a ferocious eruption of molten rock and flame. The blast swallowed the town in searing heat and ash, killing thousands and earning a place in history as the largest volcanic eruption by magma volume documented to date. Experts estimate the eruption expelled well over 160 cubic kilometers of molten rock, underscoring the extraordinary scale of this event compared with other eruptions in recorded memory.
Because so much material was hurled into the atmosphere, Tambora is described as a colossal eruption on the Volcanic Explosivity Index scale. Such events occur only once in many centuries, with only a handful of truly apocalyptic eruptions surpassing them by ejecta volume of more than a thousand cubic kilometers. A notable comparison is the Taupo eruption in New Zealand around 26,000 years ago.
The Tambora explosion sent a towering column of flame more than 20 kilometers high and could be heard as far as 2,000 kilometers away. It surpassed the power of Krakatoa, the infamous eruption that struck the same archipelago six decades later.
To help readers frame the event, the eruption of the Cumbre Vieja vent on La Palma in 2021 is far less intense by thousands of times compared with Tambora. In contrast, Vesuvius in 79 CE released about one cubic kilometer of material, roughly a hundred times smaller than Tambora’s output, and around 2,300 people died in that ancient eruption.
100,000 dead immediately
Historian Willem D’Arcy Wood notes that close to 100,000 people perished in the immediate aftermath of Tambora. The investigation into this dramatic chapter of history, including the book Tambora: The Explosion That Changed the World, helps illuminate the scale of the catastrophe and the rapid, devastating human toll.
Tambora’s effects extended well beyond Sumbawa. The eruption devastated local vegetation and triggered a chain reaction of hunger and disease as resources became scarce, with consequences rippling through neighboring islands and beyond across the Indonesian archipelago.
The mountain, once towering above 4,000 meters, shed much of its mass, altering the landscape. Ash and debris formed airborne layers that drifted toward the sea rather than building a delta, and tsunamis generated by the eruption battered coastal regions, including the Moluccas, causing further loss of life.
The Year Without Summer
The sulfur-rich cloud lifted by Tambora rose into the upper atmosphere, creating a persistent haze that lingered over Europe through the summer of 1815. The period earned its infamous nickname because sunlight dimmed and global temperatures cooled noticeably. The lingering climate shift triggered widespread crop failures and food shortages from Asia to the Americas and across Europe.
Willem D’Arcy Wood describes a prolonged phase of climate instability, noting that the cooling persisted for about three years as weather patterns shifted dramatically. This cooling contributed to famines and hardship across many regions, shaping agricultural output and economic conditions worldwide.
The social and economic fallout extended into Europe’s agricultural heartlands. Harvests fell dramatically in late 1816, with yields much lower than usual. The Netherlands faced storms that ruined crops, while France reported extensive flooding of arable land. Food prices spiked as supply lagged behind demand. In several regions, grape harvests were delayed or diminished, and successive cold years produced widespread crop losses.
As the crisis deepened, large-scale migration grew. People from Britain, Scotland, Scandinavia, Germany, and Switzerland sought better prospects in the Americas, while others moved within Europe or toward distant lands in search of opportunity. Epidemic conditions swept across regions, adding complexity to the public health landscape with outbreaks testing the resilience of communities already grappling with hunger.
Beyond hunger and disease, the social fabric of Europe strained under pressure. Grain and bread prices surged, beggars and petty thieves became more common, and rural communities faced months of economic distress. In some places, market collapses and halted agricultural activity compounded the hardship while authorities strove to stabilize food supplies and livelihoods.
As the epochal crisis unfolded, the broad human impact emerged as one of the century’s defining chapters. Many faced displacement, poverty, and health challenges that would shape demographic and economic trends for years to come. The episode stands as a stark reminder of how a single geological event can cascade into global consequences, altering societies, economies, and culture.
The monumental human drama
The episode fills historians with a stark sense of scale: the immediate toll was immense, and the aftereffects touched populations across continents. In addition to direct deaths, ensuing famines and disease outbreaks contributed to a dramatic shift in population dynamics and social structures. The broader narrative includes subsequent cholera outbreaks that amplified mortality and hardship in parts of the world.
March 1815 marked a world on the cusp of upheaval, with Napoleon attempting to reassert control in France. Military campaigns, coupled with famines and social unrest, complicated efforts to rebuild postwar Europe. The long, dreary, rainy summer of 1815 inspired literary works during a time of confinement and uncertainty. Mary Shelley drafted what would become a landmark novel while at Lake Geneva, and Lord Byron produced the poem Darkness, reflecting a world plunged into gloom.
The wider climatic anomaly that followed Tambora did not respect borders. The sky darkened, stars appeared dimmer, and a subdued solar glow cast a chill across the Northern Hemisphere. The lasting impact on daily life was profound and long-lasting, shaping diets, economies, and cultural expression for years to come.
Contemporary historical scholarship compiles the broad record of Tambora’s effects and their consequences on global history, emphasizing how the eruption reshaped not only the environment but also the social and political order of early nineteenth-century societies.