Among the topics covered by the April 11th 2015 issue of the Economist: the US presidential election, the Iran nuclear deal, terrorism in Kenya and Malaysia, and economic projections for the European Union.  It might be surprising, then, that the lead-in is an article on volcanoes and climate whose introductory setting is Indonesia in 1815.  That was the year Mount Tambora erupted.  The most powerful volcanic eruption of the past 500 years , Tambora released ash over a million square kilometers, and killed 60,000-120,000 people.  But the global impact was much more subtle.  By releasing sulfur dioxide into the atmosphere, particles reflected sunlight away from the earth, cooling and drying the planet:

The year after the eruption clothes froze to washing lines in the New England summer and glaciers surged down Alpine valleys at an alarming rate.  Countless thousands starved in China's Yunnan province and typhus spread across Europe.  Grain was in such short supply in Britain that the Corn Laws were suspended...And no one knew that the common cause of all these things was a ruined mountain in a far-off sea.

Volcanoes don't feature much in modern discourse about climate change, natural disasters, and societal resilience.  Perhaps they should.  While there is a direct risk to people and property from lava and ash, that risk is minimized by relatively sophisticated early warning systems.  The real danger may be the indirect impacts on the global environment.