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How an Icelandic volcano helped spark the French Revolution

Profound effects of eight-month eruption in 1783 caused chaos from US to Egypt, say experts
Greg Neale
guardian.co.uk, Thursday 15 April 2010 18.11 BST

Just over 200 years ago an Icelandic volcano erupted with catastrophic consequences for weather, agriculture and transport across the northern hemisphere – and helped trigger the French revolution.

The Laki volcanic fissure in southern Iceland erupted over an eight-month period from 8 June 1783 to February 1784, spewing lava and poisonous gases that devastated the island's agriculture, killing much of the livestock. It is estimated that perhapsa quarter of Iceland's population died through the ensuing famine.

Then, as now, there were more wide-ranging impacts. In Norway, the Netherlands, the British Isles, France, Germany, Italy, Spain, in North America and even Egypt, the Laki eruption had its consequences, as the haze of dust and sulphur particles thrown up by the volcano was carried over much of the northern hemisphere.

Ships moored up in many ports, effectively fogbound. Crops were affected as the fall-out from the continuing eruption coincided with an abnormally hot summer. A clergyman, the Rev Sir John Cullum, wrote to the Royal Society that barley crops "became brown and withered … as did the leaves of the oats; the rye had the appearance of being mildewed"....

Across the Atlantic, Benjamin Franklin wrote of "a constant fog over all Europe, and a great part of North America".

The disruption to weather patterns meant the ensuing winter was unusually harsh, with consequent spring flooding claiming more lives. In America the Mississippi reportedly froze at New Orleans.

The eruption is now thought to have disrupted the Asian monsoon cycle, [and] prompting famine in Egypt. Environmental historians have also pointed to the disruption caused to the economies of northern Europe, where food poverty was a major factor in the build-up to the French revolution of 1789...