Professor Sir Stephen Sparks explores an aspect of the Earth that has fascinated the human mind for centuries: volcanoes. He will examine the significance of volcanoes in an excursion into volcanology.

Huge volcanic eruptions are the only natural hazard apart from the impact of an asteroid that can cause a global catastrophe. In the short history of civilisation, a few thousand years, there have been few volcanic events that have had global effects. Much larger magnitude eruptions happened regularly when timescales of millions of years are considered. Such extreme eruptions perturb global climate for several years and can have severe environmental consequences. The modern world is uniquely vulnerable to very large volcanic events, making the study of their return periods, possible environmental effects and consequences a key goal of volcanology.

There are an estimated 800 million people living close enough to active volcanoes to be affected when they erupt. As well as casualties from volcanic eruptions there can be major economic losses and societal disruption, especially when communities must be evacuated. The eruption of Eyjafjallajökull volcano in Iceland in April-May 2010 did not kill anyone but disrupted the travel of millions of people and cost the airline industry billions of dollars. This highlighted the increasing vulnerability of modern globalised societies. New approaches to volcanic hazard assessment and risk management are emerging as more information is required to respond to volcanic emergencies – illustrated by approaches to some recent eruptions, such as the Soufriere Hills Volcano, Montserrat.

Volcanoes provide many natural resources from which society can benefit. Diamonds and most of the world’s copper are mined from eroded extinct volcanoes while many active volcanoes offer the possibility of extracting huge amounts of geothermal energy. The volcanic processes that transport diamonds to the Earth’s surface and enrich copper beneath volcanoes show how volcanoes can be a major energy and resource.

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