domingo, 25 de septiembre de 2011

EcoAlert - Iceland's Laki Volcano may be Poised for a Massive Historic Eruption

Flickr-2772596793-imageWhat if one of the largest volcanic eruptions in recent history happened today? A new study suggests that a blast akin to the Laki eruption that devastated Iceland in the 1780s would waft noxious gases southwestward and kill tens of thousands of people in Europe. And in a modern world that is intimately connected by air traffic and international trade, economic activity across much of Europe, including the production and import of food, could plummet. At least four Laki-sized eruptions have occurred in Iceland in the past 1,150 years.
From June of 1783 until February of 1784, the Laki volcano in south-central Iceland erupted, spewing an estimated 122 million metric tons of sulfur dioxide gas into the sky — a volume slightly higher than human industrial activity today produces in the course of a year, according to Anja Schmidt, an atmospheric scientist at the University of Leeds reported online in the Proceedings of the National Academy of Sciences.

Two years after the Laki eruption, approximately 10,000 Icelanders died  --about one-fifth of the population, along with nearly three-quarters of the island’s livestock. Parish records in England reveal that in the summer of 1783, when the event began, death rates were between 10 percent and 20 percent above normal.

The Netherlands, Sweden, and Italy reported episodes of decreased visibility, respiratory difficulties, and increased mortality associated with the eruption. According to one study, an estimated 23,000 people died from exposure to the volcanic aerosols in Britain alone.

To assess how such an eruption might affect the densely populated Europe of today, Schmidt created a computer simulation using weather models to estimate where sulfur dioxide emissions from an 8-month-long eruption that began in June would effect. They also estimated the resulting increases in the concentrations of airborne particles smaller than 2.5 micrometers across, the size of aerosols that are most easily drawn into human lungs and that cause cardiopulmonary distress. They also used modern medical data to estimate how many people those aerosols would kill.

In the first 3 months after the hypothetical eruption began, the average aerosol concentration over Europe would increase by 120 percent. The number of days during the eruption in which aerosol concentrations exceed air-quality standards would rise to 74, when a normal period that length typically includes only 38. Not surprisingly, the air would become thickest with dangerous particles in areas downwind of the eruption, such as Iceland and northwestern Europe, where aerosol concentrations would more than triple. But aerosol concentrations in southern Europe would also increase dramatically, rising by 60 percent.

In the year after the hypothetical eruption commences, the increased air pollution swept from Iceland to Europe would cause massive amounts of heart and lung disease, killing an estimated 142,000 people. Fewer than half that number of Europeans die from seasonal flu each year.

Image credit:  Ulrich Latzenhofer on Flickr

Image: Laki volcanic region, Iceland. (R.M.C. Lopes/NASA)
ScienceNOW &

The Daily Galaxy

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