from Sunday Herald 18 April 2010
Volcanoes can change history. About 74,000 years ago, Mount Toba on the Indonesian island of Sumatra exploded with a violence unlike any other, releasing enough pulverised molten rock to make two Everests.
The huge dust clouds that surrounded the globe blocked out the sun and caused a prolonged “volcanic winter”, scientists say. This made life very tough for humankind’s Neanderthal ancestors, reducing them to no more than a few thousand breeding pairs and for ever altering their evolution.
Compared to this, last week’s eruption in Iceland was nothing. It was not a nuclear-scale explosion, more a light flick of ash from a cigarette. Yet such is the vulnerability of 21st century international air transport that its consequences have been startling, far reaching and hugely damaging - and they could get worse.
Air travel has ground to a halt for at least three days, with mass disruption now expected to continue into next week. Apart from a handful of flights on the west coast, the UK has been in total lock-down, stranding hundreds of thousands of passengers, dislocating businesses, and wrecking countless weddings, funerals, holidays, conferences and sporting fixtures.
Flights from America into Europe have dropped by two-thirds, and up to 17,000 flights a day have been cancelled within Europe. The airlines are losing at least £130 million a day, according to the International Air Transport Association, with companies like British Airways and Lufthansa facing losses of maybe £10 million a day.
There were fears yesterday that supermarkets could run short of perishable goods, freighted in by air, particularly if the disruption continues for several more days. Waitrose warned that supplies of fresh pineapple chunks from Ghana and baby sweet corn from Thailand had already been hit.
Britain’s main handling centre for perishable air freight at Heathrow in London has been at a standstill. If the no-fly ban is prolonged, it could begin to restrict supplies of asparagus, grapes, lettuce and pre-packed fruit salads.
Kenya’s lucrative market selling flowers abroad, which accounts for a fifth of all the country’s exports, has also suffered. According to the Kenya Flower Council, it was costing growers up to £1.3 million a day, and there were 500 tonnes of flowers waiting in cold storage at Nairobi airport.
Of course there are winners too, with train, coach and ferry companies all putting on extra services, and reporting large jumps in passengers. Eurostar said its trains to Paris and Brussels were “extremely busy” this weekend. P&O cross-channel ferries warned foot passengers it couldn’t accept any more bookings until Wednesday.
NorthLink, which runs ferries from Aberdeen to Shetland, put on an extra ferry yesterday. There had been “unprecedented last-minute demand for places”, said the company.
Eruption continues
Nobody, as far as is known, has so far died because of the volcanic ash spewing out of the Eyjafjallajökull volcano near Iceland’s south coast. But there are few signs that it is going to stop any time soon, suggesting that the travel chaos will persist.
“The volcano continues to erupt, in fact reports last night suggest that it’s more active than it previously was,” Paul Haskins, head of safety at the National Air Traffic Services (NATS) said yesterday.
“The ash is continuing to be emitted into the atmosphere and the weather conditions are blowing it down towards UK air space. So for safety reasons, we have had to apply the international contingency plans.”
Dr David Rothery, a earth scientist from the Open University, said that “a significant quantity” of ash was being ejected from the volcano yesterday morning. This suggested that fresh explosions were taking place in the crater.
Columns of smoke full of fine ash could be seen more than five kilometres high, and they were highly likely to be drawn into the high altitude winds bringing the ash into European airspace, he added. “While this situation and the present wind conditions persist, I think it unlikely that the restrictions placed by NATS on air traffic will be eased.”
The Met Office forecast that the weather conditions would not change quickly. "The latest information we have suggests the ash will remain over the UK for several days,” said professor Brian Golding, the office’s head of forecasting.
"We need a change of wind direction that stays changed for several days and there is no sign of that in the immediate future.”
Experts pointed out that the Eyjafjallajökull eruption was, in volcanic terms, relatively minor. “The Iceland eruption is, at least so far, a very small one and eruptions like this happen all the time,” said Jon Davidson, from the University of Durham.
The type of eruption and the weather had just conspired to make its impact so dramatic. “The only reason we are noticing this eruption is that the ash plume has been steered by atmospheric currents into our air space and is therefore disrupting air traffic,” he explained.
According to Davidson, anything that circulates air can be damaged by volcanic ash, including cars, trains and building ventilation systems. “The economic impact can be far reaching,” he said.
More eruptions in the future
If Eyjafjallajökull, or one of Iceland 34 other active volcanoes, had a major eruption, the consequences could be far worse. Volcanologists have argued that if the kind of eruption that occurred from Mount Laki in 1783 and 1784 happened now it would completely prevent aviation in the North Atlantic for months.
“Such a large eruption occurring today would have the potential to severely affect air travel at high northern latitudes for six months or more,” said Bill McGuire, from the Benfield Hazard Research Centre at University College London
“The last eruption of Eyjafjallajökull lasted more than 12 months. If this eruption has a similar duration then ash could periodically present a problem in UK air space for some time.”
Professor Steve Sparks, an environmental risk specialist at the University of Bristol, pointed out that the Laki eruption was huge compared to the current activity. He suggested that the crop failures and famines triggered by the eruption could have helped foment the French Revolution, which started in 1789.
The trouble is that such major eruptions may be more likely in the future. “Volcanic activity on Iceland appears to follow a periodicity of around 50 to 80 years,” said Thorvaldur Thordarson, a volcanologist at the University of Edinburgh.
“The increase in activity over the past 10 years suggests we might be entering a more active phase with more eruptions,” he told New Scientist magazine. The eruptions could be bigger, and the enhanced activity could last for 60 years or so.
This is supported by research from the University of Iceland showing that the island’s volcanoes have gone through cycles of low and high activity over the last 800 years. High volcanic activity is linked to earthquakes along the tectonic faults that split the area, which have also increased recently.
Occasionally, volcanoes can be ripped by massive explosions, like that at Mount Toba 74,000 years ago. Mount Pinatubo in the Philippines put 10 cubic kilometres of shattered rock into the air in 1991, causing the average global temperature to drop by half a degree centigrade.
The biggest eruption in recorded history may have been at Mount Tambora in Indonesia in 1815. It killed over 70,000 people, and led to an average drop in temperature up to 0.7 degrees centigrade.
1816 became know as the “year without summer”, damaging crops across the northern hemisphere. It was immortalised in Lord Byron’s poem Darkness: “The bright sun was extinguished, and the stars did wander darkling in the eternal space.”
The worst-case scenario now is a super-eruption in a heavily populated area, something that’s never been experienced before. “It would have devastating consequences,” said Dr Michael Branney, a volcanologist from the University of Leicester.
But the research is still in its infancy, so it is difficult to be specific about frequency or likelihood. Over the millennia, there are known to have have been a series of huge explosions in the area of Yellowstone park in the United States.
“There are numerous potentially very hazardous volcanoes around the world,” said Dr Branney. “The Taal caldera volcano in Luzon, in the Philippines, has a population of 12 million or so living on the deposits of the previous eruptions.”
Background: active volcanoes in Europe
There are about 40 active volcanos in Europe, 35 of which are in Iceland. As well as Eyjafjallajökull, which was spewing ash into the upper atmosphere last week, the two most famous are mounts Hekla and Katla, known as the ‘angry sisters’.
They all lie on the North Atlantic Ridge, an unstable geological area where the Eurasian and North American tectonic plates meet. Eruptions start when boiling liquid rock, deep under the ground, finds a weak point in the Earth’s crust and and bursts through.
Eyjafjallajökull started erupting 20 March, causing 500 local farmers to be evacuated and flights in Iceland to be cancelled. But then last Wednesday it erupted again, this time more violently.
The boiling rock, or magma, broke through under a glacier and rapidly melted the ice. It reacted explosively with the water to produce tiny particles of glass-like ash which were lofted high into the sky - just at the right height to clog up jet engines.
The last time Eyjafjallajökull erupted, it lasted for two years from December 1821 to January 1823. Hekla last erupted recently in 2000, resulting in a seven kilometre flow of lava and ash in the sky.
Katla’s last major eruption was in 1918, though it suffered a smaller eruption in the 1950s. Another of Iceland’s big volcanoes, Mount Grimsvotn, erupted in 1996 and again in 2004, when it dumped ash on Scandinavia.
Further back, eruptions at Grimsvotn and the neighbouring Mount Laki between 1783 and 1785 spread lava over 300 square kilometres, blotted out the sun and killed 9,000 people - a quarter of the population - by poisoning or famine.
There are also volcanoes under the sea off Iceland, which occasionally erupt and create new islands. This last happened in 1963, when the island of Surtsey appeared.
The most volcanically active European country outside Iceland is Italy, which is home to three well-known volcanoes. Stromboli, a small island off the north coast of Sicily known as the ‘lighthouse of the mediterranean’, has been continuously erupting for the last 20,000 years.
Mount Etna on Sicily has erupted at least six times times in the last ten years, most recently on 8 April. Mount Vesuvius, on the bay of Naples and the only volcano on mainland Europe, famously obliterated Pompeii in 79 AD, killing up to 25,000 people.
Vesuvius also had major eruptions in 1906, 1926, 1929, and 1944, though it has been quiet since then. It is regarded as one of the world’s most dangerous volcanoes because of its tendency to erupt explosively - and because it is surrounded by three million people.
There is also a big volcano off Greece, on the Santorini archipelago of islands in the Aegean Sea. It was the site of one of the largest volcanic eruptions in recorded history some 3,600 years ago.
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