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. The ash released by volcanoes disrupts supply chains dependent on air transportation, as the Eyjafjallajokull eruption in Iceland demonstrated in 2010 when air travel bans led to $1.7 billion in losses for the airline industry alone. The climate change caused by a large eruption would be far-ranging and hard to predict. Models suggest a general cooling of the planet would also decrease precipitation in areas like the Amazon, India, and China, populous regions dependent on regional food production.
In my recent article on droughts, floods, and wildfires, I talk about the challenge of proactive disaster planning when risks accumulate gradually. In the case of volcanoes, the vulnerability of nearby populations can be reduced by developing warning systems and evacuation routes, and there are a wealth of resources and research available for communities to do so.
Reducing the global economy's vulnerability to the ash cloud and subsequent cooling and drying of the planet is a much harder task. Cooperation between governments would help, and the arbitrary nature of volcanic climate impacts would justify an egalitarian global response plan. But there isn't an intergovernmental body or legal instrument designed to address volcanic eruptions at the present time. And unlike natural disasters that have extreme and immediate impacts (like floods and earthquakes that elicit generous international relief), the planetary cooling and drying caused by a volcanic eruption would develop slowly (like droughts, which receive little international relief). It would also be difficult to make definitive causal links between an eruption and its effects, such as a subsequent decline in crop yields two years later.
Countries should start thinking about an international or intergovernmental large volcanic eruption response plan to address these issues. The odds of a large volcanic eruption on the scale of Tambora in 1815 are small but not insignificant. Given the global and disruptive impacts that kind of eruption would have, it's worth thinking about ways to increase resilience to volcanoes. Proactive planning would be a good start.
4/20/15 Update: The International Business Times reports on a study led by the European Science Foundation that echoes my call for an international response plan. The researchers are concerned that low-probability, high-impact natural disasters receive insufficient attention from the public because we lack experience with them. A framework for monitoring, building resilience, and responding to these disasters is sorely needed. The most troubling potential disaster? Volcanoes. Money quotes:
Among geohazards (volcanic eruptions, earthquakes, tsunamis, landslides, floods, droughts, and bolides), large volcanic eruptions pose the most severe threat.
An informed global governance system capable of responding to emerging global threats and coordinating measures to increase preparedness and general resilience with the goal of reducing the global disaster risk (is needed).
The International Charter on Space and Major Disasters should be extended to cover cases of emerging threats for early warning purposes prior to the occurrence of a disaster.