Tuesday, April 14, 2015

Volcanic Eruptions Endanger World Systems

This graphic is from an interesting article in the current issue of The Economist. It suggests that, while there are many factors that determine climate such as El Nino/La Nina, the huge volcanic eruption in the 13th century is implicated in the Little Ice Age.
Mount Tambora....., a volcano on the Indonesian island of Sumbawa, was once similar in stature to Mont Blanc or Mount Rainier. But in April 1815 it blew its top off in spectacular fashion. On the 10th and 11th it sent molten rock more than 40 kilometres into the sky in the most powerful eruption of the past 500 years. The umbrella of ash spread out over a million square kilometres; in its shadow day was as night. Billions of tonnes of dust, gas, rock and ash scoured the mountain’s flanks in pyroclastic flows, hitting the surrounding sea hard enough to set off deadly tsunamis; the wave that hit eastern Java, 500km away, two hours later was still two metres high when it did so. The dying mountain’s roar was heard 2,000km away. Ships saw floating islands of pumice in the surrounding seas for years........ 
The year after the eruption clothes froze to washing lines in the New England summer and glaciers surged down Alpine valleys at an alarming rate. Countless thousands starved in China’s Yunnan province and typhus spread across Europe. Grain was in such short supply in Britain that the Corn Laws were suspended and a poetic coterie succumbing to cabin fever on the shores of Lake Geneva dreamed up nightmares that would haunt the imagination for centuries to come. And no one knew that the common cause of all these things was a ruined mountain in a far-off sea.
The article goes on to suggest that while huge volcanic eruptions such as those described above are rare, they almost certainly will reappear. The global food system is now more global, and if food production is disrupted on one continent, production on other continents might help make up the shortfall; indeed, if production in the northern or southern hemisphere is disrupted, the shortfall might be partially made up on the other. Still, more greenhouses and hydroponic production capacity might be advisable.

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