The Icelandic eruption is obviously of great interest to students as part of their hazards studies for Unit 1 (and possibly unit 4). There is no shortage of films, maps, articles etc in the newspapers covering this story. For instance:
BBC - good for overall analysis of the physical event at http://news.bbc.co.uk/1/hi/uk/8625813.stm
and a running commentary at http://news.bbc.co.uk/1/hi/uk/8626765.stm
FT - good for economic impacts  (including airline share price falls) at http://www.ft.com/cms/s/0/eba8c76e-4983-11df-9060-00144feab49a.html
Guardian - good overview of many geographical themes, including http://www.guardian.co.uk/world/2010/apr/15/iceland-volcano-eruption-evacuated and http://www.guardian.co.uk/travel/2010/apr/16/iceland-volcano-tour-operator-tourism

Key themes to explore with a class to help them link their understanding of this specific event with their Unit 1 studies could include:

1. Categorising the type of hazard. A geophysical event – occurring at a constructive plate boundary - has led to enormous quantities of ash being added to the atmosphere by the Eyjafjallajokull volcano; however, the ash cloud, or plume, has been spread by atmospheric processes so its is partly meteorological in nature too. Interestingly, Iceland itself has not really suffered. (This is similar to what happens with tall industrial chimneys – pollution is carried away from the factory to pollute other areas but not the actual polluter!)
2. Thinking about the distribution pattern. Following on from the point above, it is the westerly upper air circulation (of which the fast moving jet stream belt forms a part) that has determined which areas are being adversely effected by the dust cloud. The scale of the event is planetary-wide - the dust is travelling 1000s of kms.
3. The disaster equation. For an event of this scale, the disaster potential is higher than it would have been during the last eruption of Eyjafjallajokull in 1821 This is because the widespread use of jet airplanes has greatly increased western society's vulnerability. The dust is in the upper atmosphere and would not impact on our lives were it not for the fact that we now routinely travel through this region whenever we fly. Aeroplanes are vulnerable to the ash (if it enters their engines) and must be grounded while the ash is overhead. The economic impacts are, as a result, enormous. The costs to business, tourism etc are really adding up. Some British rock bands have even had to cancel their international tours! Also worth noting that past events of this type have sometimes led to fatalities due to the poisonous nature of the gas. “The  eruption at Laki in Iceland in 1783 could be an awful precedent. That emitted an estimated 120m tonnes of sulphur dioxide and a vast quantity of extremely fine dust, which caused a persistent haze across western Europe for many months – and is estimated to have killed tens of thousands of people through respiratory and other illness.” (FT, 16 April)

Probably the most important thing to remember if using this as a case study in an exam is to make sure you can be specific about the nature of the economic impacts that the event has brought to the UK – highlighting the vulnerability of aeroplanes and the industries that rely upon them.

Thank Simon - this is great.

Was supposed to be touching down at Heathrow just about now but am stranded, ironically, in volcano-studded Japan... I am living the vulnerability of jet airplanes bit of the disaster equation if you like (incidentally the economic impact will be very positive for airport hotels!)

The last eruption of Eyjafjallajokull, in 1821 you mention, lasted for a year so it might be quicker for me getting a less vulnerable ship home?

Jon

Jon Wolton, you appear to be trapped in a geography case study. When will you be able to come home?

Here are some more teaching ideas based around the eruption, showing just how synoptic the themes are.

Unit 1. (Global networks.) 16 April 10. "Thousands stranded after trip plans dashed." 16 April 10. Clouds of volcanic ash brought travel chaos to Europe as airports across the continent closed, leaving planes grounded and thousands of travellers stranded. People are seeking alternative routes via rail and sea.  This story links with the other part of Unit 1, Going Global, and not just World at risk. The reason? Like the credit crunch two years ago, we have seen apparently ‘unstoppable’ globalisation become seriously challenged. Students could read through this article (treating it as if it is part (a) for an essay question), and then write a mini-essay titled “Explain how the growth and functioning of global networks can be affected by physical factors.’  It’s a tough title, to be sure – but they can structure it into two main parts [firstly, growth – think about the distances between continents that have to be overcome with undersea cables, etc; secondly, functioning – write a short account of the ash cloud’s impact on transport networks]. Mark out of 10.
http://www.ft.com/cms/s/0/adeb179a-48ef-11df-8af4-00144feab49a.html

Unit 1. "Iceland volcano causes fall in carbon emissions as eruption grounds aircraft." 19 April 10. Another nice Unit 1 link here – this time to the causes of climate change. As the Icelandic volcano Eyjafjallajokull continues to pump ash into the sky, experts have been considering whether the ash cloud can be expected to have any impact on the planet's climate. It seems unlikely that the eruption is large enough to significantly reduce temperatures  by reflecting solar radiation. However, the flight ban has stopped emissions of an estimated 2.8m tonnes of CO2. Although the volcano is emitting CO2 itself, the net impact on global CO2 levels will still be a lowering of the rate of increase, because of the mass grounding of flights.  Volcanoes produce about 200m tonnes of carbon dioxide every year. Students could legitimately use all of these ideas in a write-up of the following 4-mark section A question: Explain how volcanic activity can impact on Earth’s climate.
http://www.guardian.co.uk/environment/2010/apr/19/eyjafjallajokull-volcano-climate-carbon-emissions

Unit 1. (Geological Hazards/Climate Change.) "Scientists call for research on climate link to geological hazards" 19 April 10. Experts say suggestions that climate change could trigger more volcanoes and earthquakes are speculative, but there is enough evidence to take the threat seriously. It has been suggested that there should be further research into whether more volcanoes, earthquakes, landslides and tsunamis are triggered by rising global temperatures. Experts say global warming could affect geological hazards such as earthquakes because of the way it can move large amounts of mass around on the Earth's surface. Melting glaciers and rising sea levels shift the distribution of huge amounts of water, which releases and increase pressures on the Earth’s crust. A fascinating piece, showing interesting overlap between geo-phys and hydro-met hazards.
http://www.guardian.co.uk/environment/2010/apr/19/climate-change-geological-hazards