Tuesday, April 20, 2010

The long-term socioeconomic impact of the Eyjafjallajoekull (actually, Eyjafyoll) eruptions

First, let's deal with the name. According to the London Telegraph, the long name commonly used to refer to the Icelandic volcano that is causing so many travel problems in Europe is really the name for the glacier that covers the crater. The volcano itself is called Eyjafyoll (Ay-uh-fyotl).

As for the long name: "Eyja means island, fyalla or fyjoll means mountain, and jökull means glacier, so the name actually means the island mountain glacier," said Urdur Gunnarsdottir, of the Icelandic Foreign Office.

But now to the potential socioeconomic implications of the eruption.

An article I read this morning from Markman Capital Insight encouraged me to look at historical results of volcanic eruptions--not only of Eyjafyoll but of others.
  1. Notice that eruptions of Eyjafyoll have been associated (somewhat weakly, it seems) with eruptions of Katla, a much larger volcano about 25km east northeast of Eyjafyoll. According to The Economist, "two or three (depending on who’s counting) of the 23 eruptions of Katla over historical times (which in Iceland means the past 1,200 years or so) have been preceded by eruptions of Eyjafjallajokull."
    There is no geophysical evidence for a causal relationship between such eruptions — no indication that the two volcanoes share the same plumbing — and since Katla erupts more often than Eyjafjallajokull the effect could just be coincidence. . . . That said, Katla does seem to erupt on a semi-regular basis, with typical periods between eruptions of between 30 and 80 years. The last eruption was in 1918, which makes the next overdue.
    And if Katla blows, it could be big, indeed.
    When it comes to lava output, its eruptions can be 100 times larger than what is going on at Eyjafjallajokull. This would be far more disruptive for the people living in southern Iceland and could also do harm much further afield. A very large eruption, thought to be one of Katla’s, left ash all across northern Europe about 10,300 years ago. When explosive volcanic eruptions in Iceland and elsewhere in the Arctic are large enough to insert significant long-lasting hazes into the upper atmosphere they can change weather patterns around the world.
    . . . And that's the first major, long-lasting socioeconomic outcome we might want to consider.
  2. According to Dr. Andrew Hooper, an Assistant Professor of Geology at Delft University of Technology and an expert on monitoring deformation of Icelandic volcanoes,
    At the end of the last ice age, the rate of eruption in Iceland was some 30 times higher than historic rates. This is because the reduction in the ice load reduced the pressure in the mantle, leading to decompression melting there.

    Since the late 19th century the ice caps in Iceland have been shrinking yet further, due to changing climate. This will lead to additional magma generation, so we should expect more frequent and/or more voluminous eruptions in the future.
    And if that's the case, as The Economist article concludes,
    Iceland has other [volcanoe]s capable of even greater nastiness [than Eyjafjoll and Katla]. The eruption of Oraefajokull in 1362 may have been almost as large as that of the Philippines’ Mount Pinatubo in 1991, which was the largest eruption of the 20th century. The Laki eruption of 1783 sent poisonous gases far and wide across Europe. And there is evidence that some of the island’s volcanoes, especially those under the central ice cap, (which, other things being equal, will produce more dusty and explosive plumes if they break through) may be in cahoots, their average activity rising and falling in a cycle of about 130 years. On this analysis, the past few decades have been one of the quiet patches. It seems likely that the first 50 years of jet travel across the North Atlantic enjoyed, in historical terms, particularly clear skies.
    --Which, if we turn the logic around, means future international travel could be extremely difficult for quite some time.

    (By the way, apparently, volcanic ash has been of such a concern that there have been at least two international conferences on "Volcanic Ash and Aviation Safety." The second such conference was held back in June of 2004. "What's at risk from the 550 historically active volcanoes worldwide?" asks the cover page of the conference agenda.
    • Thousands of airline flights--more than 80 commercial aircraft unexpectedly encountered volcanic ash in flight and at airports.
    • Safety--hundreds of thousands of passengers
    • Billions in airline resources annually--costs of up to $80 million in repairs to a single aircraft
  3. I just quoted The Economist's minor reference to Laki. Let's take a closer look at what someone else has said about that particular eruption.

    This is from How an Icelandic volcano helped spark the French Revolution by Greg Neale, founding editor of BBC History Magazine, in The Guardian.
    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. . . .

    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".

    The British naturalist Gilbert White described that summer in his classic Natural History of Selborne as "an amazing and portentous one … the peculiar haze, or smokey fog, that prevailed for many weeks in this island, and in every part of Europe, and even beyond its limits, was a most extraordinary appearance, unlike anything known within the memory of man.

    "The sun, at noon, looked as blank as a clouded moon, and shed a rust-coloured ferruginous light on the ground, and floors of rooms; but was particularly lurid and blood-coloured at rising and setting. At the same time the heat was so intense that butchers' meat could hardly be eaten on the day after it was killed; and the flies swarmed so in the lanes and hedges that they rendered the horses half frantic … the country people began to look with a superstitious awe, at the red, louring aspect of the sun." . . .
    And having survived an unusually hot summer, the following winter was exceptionally cold. The Mississippi River is reported to have frozen at New Orleans!

    Keep moving and you've got Asian monsoons no longer operating as they do normally, a major famine in Egypt, economic upheaval across northern Europe. . . . Indeed, "food poverty was a major factor in the build-up to the French revolution of 1789."
  4. For just one more example of volcanic impact, consider the eruption of Krakatoa in the Sunda Strait back in 1883. I encourage you to read the entire article in Wikipedia. It gives you a good idea of the potential effects of a large volcanic eruption. (From an immediate, physiological perspective only, "The pressure wave generated by the colossal final explosion radiated from Krakatoa . . . was so powerful that it shattered the eardrums of sailors on ships in the Sunda Strait and caused a spike of more than two and half inches of mercury in pressure gauges attached to gasometers in the Jakarta gasworks, sending them off the scale. The pressure wave radiated across the globe and was recorded on barographs all over the world, which continued to register it up to 5 days after the explosion. Barograph recordings show that the shockwave from the final explosion reverberated around the globe 7 times in total.")

    But from a climatic perspective, "In the year following the eruption, average global temperatures fell by as much as 1.2 °C (2.2 °F). Weather patterns continued to be chaotic for years, and temperatures did not return to normal until 1888."

    Or, as Jon Markman commented in the article that originally inspired this one, Krakatoa "threw up so much ash that crops were devastated as far away as the United States. Appearing at a time when the U.S. economy was fragile anyway, it kicked off a financial panic and turned a recession into a brief depression."
Yes, indeed. Quoting historian John Murray: "Volcanic eruptions can have significant effects on weather patterns for from two to four years, which in turn have social and economic consequences. [And, as a result, w]e shouldn't discount their possible political impacts."


One final note. About the ash that is coming from Eyjafoll.

According to The Economist article:
Eyjafjallajokull is not a very big [volcano]. It is, however, particularly good at producing fine-grained ash — the sort of stuff that can hang in the air for days. . . .

The fineness of the ash is, says Thorvaldur Thordarson, an Icelandic volcanologist, unusual. Ash particles are normally in the 50-100 micron (0.05 to 0.1 millimetre) range. But at a site 50km east of the eruption, 24% of the ash falling to the ground was in the form of particles 10 microns or less in size. Studies of ash captured from the air show that for every one of the largest particles (about 300 microns) there are a million or more in the 2 micron range. So though the total volume of the eruption, put at about 0.14 cubic kilometres, is low, the amount of ash capable of travelling long distances is high.
Causes for this unbelievably fine grain:
  1. The viscosity of the lava from which the ash is made. (Higher viscosity means gases are trapped more completely within the lava. When they are finally released, they go with a bang - producing a finer grain.)

  2. The fact that the eruption is occurring under water/under ice means the steam generated by the eruption itself also contributes to forceful explosive forces further pulverizing the ash and yielding finer dust.
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