Via The Guardian, thoughts on the 200th anniversary of the great eruption of Tambora in Indonesia: Are we ready for the next volcanic catastrophe? Excerpt:
On 5 April 1815, a titanic explosion hurled a cloud of ash to a height of more than 30km. Violent, but short-lived, the blast lasted just two hours, after which the volcano returned to a state of brooding menace.
According to the lieutenant governor, Thomas Stamford (later Sir Stamford) Bingley Raffles, to whom volcanologists are indebted for his accounts of the eruption, the detonation was so loud that it was mistaken across Java for cannon fire, causing consternation among the British troops, which had ousted the Dutch and French forces just a few years earlier.
But the blast was small beer in comparison with what followed. After five days of relative calm, the climactic phase of the eruption began with a colossal explosion that launched a towering column of ash to the edge of space.
For four or five days, utter blackness reigned across the island as the hurricane blasts of hot ash and scalding gas – known as pyroclastic flows – scoured the flanks of the volcano of everything and everyone, and drifts of ash metres thick entombed what few signs of life remained.
When the explosions ceased and the darkness finally lifted, the view revealed was a vision of Tolkien’s Mordor; a grey landscape within which nothing lived or moved. The top 500m of the volcano was gone, blasted into smithereens, and replaced by a 6km-wide maw from which steam spiralled skywards.
Communities on the flanks of the volcano had vanished, along with the lives of around 12,000 men, women and children. These, perhaps, were the lucky ones, as a further 60,000 survivors of the eruption succumbed slowly and agonisingly to famine or disease.
But the consequences were not confined to this Indonesian backwater. The explosion was heard 2,600km away in Sumatra, while giant rafts of floating pumice – some kilometres in length – clogged shipping routes for years. The 50 cubic kilometres or so of ash ejected over the course of the eruption returned to earth in the following days and weeks, leaving a thick covering as far away as Borneo, 500km to the north.
In addition to the ash, an estimated 200 million tonnes of microscopic sulphur particles pumped into the stratosphere, spread outwards from Sumbawa to form a giant aerosol veil that enclosed the planet and acted as a block to incoming sunlight.
The consequences for the developed societies of the northern hemisphere were dire. A dry, sulphurous, fog draped itself across the landscape of eastern North America, causing temperatures to plunge and bringing unprecedented summer cold. In New York State, snow fell in June, while the bitter cold and killing frosts wiped out crops and halved the length of the growing season across much of the region.
On the other side of the Atlantic, Europe saw summer temperatures down by 2C compared to the average for the decade; the unseasonal cold accompanied by incessant rains and – into the following winter – by unusually powerful storms. Analysis of climate records reveals that 1816, the so-called “year without a summer”, was the second coldest in the northern hemisphere of the past six centuries.
The alleged cultural implications of this “volcano weather” for Europe are somewhat whimsical. The brilliant, gas-charged, sunsets have been declared by some to have provided the inspiration for some of JMW Turner’s more flamboyant skies. In a similar vein, the damp and gloom of the 1816 summer has been charged with setting the scene for both Lord Byron’s grim vision Darkness, and Mary Shelley’s gothic novel Frankenstein.
For the less well-to-do of Europe, however, the Tambora eruption brought nothing less than hunger, disease and death. Widespread harvest failure resulted in the most serious famine for more than a hundred years, doubling the price of grain and spawning bread riots and widespread civil unrest.
Such was the degree of breakdown of food supply that economic historian John Post has called the episode “the last, great subsistence crisis in the western world”. Malnourished and weakened, the starving succumbed rapidly to disease, with typhus in particular rife. Many tens of thousands are thought to have died across the continent, including more than 40,000 in Ireland alone.
Click through to read some informed speculation on how we might handle such an eruption today. Eric Klemetti's Eruptions blog discusses just how big the eruption was. In 2013 I wrote a review in The Tyee of a book about the impact of Tambora.